January 22, 2024 • 50 mins
What aspects of the brain differ between autistic people and non-autistic people? Do these brain differences lead to things like synesthesia in autistic people? Synesthesia is when your senses or perceptions overlap, like when you think of a number and see waves of red or some other colour. Or when you can feel in your own body the sensations and physical pain of another, just by looking at them!
In this episode, I also talk about ableist perspectives in autism research, secondary autism, neurons, glial cells, early brain development, mirror-touch synesthesia as the basis of deep empathy, and much more!
Watch this episode on YouTube.
If you'd like to know more about topics discussed in this episode, check out:
"What Is Synaptic Pruning?" by Jacquelyn Cafasso
"Astroglia in Autism Spectrum Disorder" by Kinga Gzielo and Agnieszka Nikiforuk
"Regional Differences in Synaptogenesis in Human Cerebral Cortex" by Peter Huttenlocher and Arun Dabholkar
"Microglia in the Pathogenesis of Autism Spectrum Disorders" by Ryuta Koyama and Yuji Ikegaya
"Astrocytes and Microglia and Their Potential Link With Autism Spectrum Disorders" by Francesco Petrelli et al.
"Balancing Excitation and Inhibition in the Autistic Brain" by Charlotte Pretzsch and Dorothea Floris
"Synaptic Growth, Synesthesia and Savant Abilities" by Martin Silvertant
"Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons" by Stephen D. Skaper et al.
"Lack of Neuron 'Pruning' May Be Behind Many Brain-Related Conditions" by Clare Wilson
"Microglia and Astrocytes Underlie Neuroinflammation and Synaptic Susceptibility in Autism Spectrum Disorder" by Yue Xiong et al.
Episode outro music: "It's Too Much" by Kristen Hovet
Theme music: "Everything Feels New" by Evgeny Bardyuzha.
All episodes written and produced by Kristen Hovet.
Send in your questions or thoughts via audio or video recording for a chance to be featured on the show! Email your audio or video clips to otherautism@gmail.com through WeTransfer.
Buy me a coffee!
Buy The Other Autism merch. Use code FREESHIP for free shipping on orders over $75 USD!
The views, opinions, and experiences shared by guests on this podcast are their own and do not necessarily reflect those of the host or production team. The content is intended for informational purposes only and should not be taken as medical or professional advice. Please consult with a qualifi
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Kristen Hovet (00:00):
Hey everyone, my name is Kristen Hovet.
Welcome back to The OtherAutism podcast.
Today we're talking aboutneural pruning and how it
differs in the brains ofautistics versus the brains of
neurotypicals.
I'll also discuss synesthesia.
I don't know if I'm saying thatright.
I'm saying it.
I think I tried getting GoogleTranslate to help me and I'm
(00:23):
still not saying it right.
So, actually, speaking ofGoogle Translate, I think she's
going to help me in this episode, so I'm going to need her here.
One sec, okay, synesthesia.
Synesthesia, yeah, where onesensory or cognitive pathway
activates a second or maybe eventhird sensory or cognitive
(00:46):
pathway.
But before we get into all ofthat, I wanted to say sorry for
the long gap of time betweenthis episode today and the last
one in November.
So a lot has happened betweenNovember and today, which is
January 21st.
I did have an interview linedup for December and we had to
(01:08):
cancel it last minute and thenholiday rush began, so I didn't
have time to set up somethingelse.
And there's other reasons too.
I probably could have fitsomething in there if I was at
my usual healthy, energized kindof self.
So I finished my Master ofHealth Studies degree with a
(01:32):
major in health research inDecember, then went away for a
while for the holidays, then Igot sick a few times and now I'm
back.
So my degree, as some of youknow, took three years to
complete.
I was considered a full timeMaster's student and I was also
working for most of that workingfull time at the same time.
(01:55):
It would have taken me fouryears in the program I was in,
but I did have some Master'slevel classes under my belt from
before I had cancer, before Iwas diagnosed with cancer, when
I was still pursuing a Master'sin counseling psychology.
I got to use those classestowards my degree, thankfully.
(02:16):
Anyway, the last three yearshave been a lot.
It's been a lot of really goodthings and a lot of very
challenging things.
Also,so while I was in school and
working, I went through the endof an almost 12 year long
relationship that upendedeverything, including, I mean,
(02:39):
that has an impact on your self-concept.
It has an impact on how youspend your time and it leads to
a sort of having to likereadjust everything, your
schedule, how you spend yourfree time.
It impacts everything.
So I went through the end ofthat and, about a year and a
(03:01):
half after that, the beginningof an amazing new relationship.
I also worked through griefrelated to the loss of my
brother and the loss of a friend.
Not to mention, I moved twicein the past two years alone.
And then, when I moved to mycurrent place here, I got
(03:22):
evacuated from fires this pastsummer, so that was literally
like a couple months after Imoved.
It's like, now you have to runaway from fire and you have to
stay out of your house for aweek, and I was lucky that I had
a place to stay, because noteveryone was so fortunate and
some people lost their homes.
That was terrifying and I sortof just kept trucking along.
(03:48):
I got back home and just kindof almost tried to forget that
that all had happened, becauseit was just like, really like,
really, you're gonna, this isgonna be what's happening right
now.
So anyway, on top of all of that, there was significant work
related stress that I've beendealing with off and on, I would
say, for a long time, and Ienjoy my work, but there are
(04:11):
some stressful elements.
And I think all of it justfinally caught up with me.
I have a lot of things in placeto sort of like deal with
impacts of stress and deal withimpacts of challenging life
events happening, but it's likeall of those, those resources
(04:33):
and things I have in place werenot enough, I don't think, and
it all just kind of caught upand I was just blindsided by the
after effects, all of a sudden.
I found myself pretty burnt out, despite, like I said, so many
good things going on and so manyelements that bring resilience
(04:56):
to my life, like, I thinkinternal elements and also
support system outside of myself.
I also have, like I stick to apretty clear routine, a pretty
strict sleep schedule, all thesethings that I know to help
myself.
It was just not enough and whathappened was like I've
(05:17):
experienced burnout before,which I did talk about,
ironically, last couple episodesago.
I was talking about burnout.
If you heard that one, you knowthat I've experienced burnout
before, and this one was like itcame up very, very slowly and
then it just knocked me off myfeet.
What happened was I was able toevery day, get through the
(05:39):
workday, do my work, concentrateon work, and after that, when I
would normally do some errandsand then work on a podcast or do
something like that, I couldn'tdo anything else for the rest
of the day other than washingdishes and vacuuming and then
playing with my cat and thenwatching TV.
(06:01):
Like I really, I had zeroenergy for anything more,
unfortunately, and there were somany things I wanted to do with
the podcast and so many emailsI wanted to respond to and I
just.
I appreciate that several ofyou took the time to check in
and I fairly confidently can sayI'm back.
(06:25):
I don't know if I'm going to beable to keep up the two or
three episodes a month.
We'll see.
Ideally, as I've said before, Iwould love to have The Other
Autism be my full-time job.
That is my dream.
Unfortunately, I'm not quiteclose there yet.
I don't know if a lot of youknow, but to be part of the
(06:48):
bigger advertising groups or toget in on the bigger advertising
that podcasts do, you have tohave 10,000 listens per episode,
to even sign up for a lot ofthose.
Actually, most of them havesome very strict guidelines like
that and I'm not quite thereyet for that many per episode.
(07:13):
But that's my goal to get thereand to be able to give you more
content, more interviews, anddo a lot of other things.
It's my goal, my dream, to beable to do that.
I felt like this was asignificant stumbling block this
past couple months and I reallydon't want it to happen again.
(07:35):
I can't promise that it won't,but I don't foresee all the
things that happened in the lastfew years happening ever again
to me.
Knock on wood.
But I don't foresee all ofthose things happening again or
happening in such quicksuccession, one after the other,
(07:57):
the way that they have.
I could have chosen an easiersubject for myself, in the face
of burnout especially, but onceI started reading about it, I
knew I had to do this episodeand I knew it had to be the
first one of 2024.
The topics I'm going to covertoday are, as I said, not easy.
For that reason, I'm going totry to take it slow and break
(08:19):
things down without getting toodeeply into the weeds or the
unnecessary details.
I think it's important, too,since the research is still
underway in this area, to keepthings a bit high level, and
what I mean by high level hereis that I'll try to stick to
more general summaries asopposed to getting into the
(08:40):
minute biological, neurologicaldetails.
I also wanted to mention that Iwas a bit disturbed while I was
reading the research on theseneurological, brain-based
aspects of autism.
I found that the language usedin a lot, not all, but a lot of
the content was quite in linewith the deficit model of autism
(09:00):
and a lot of it seemed focusedon like oh, if we understand
these neurological differencesin autistic brains, then one day
we might be able to fix them.
I just want to say that's soagainst what I stand for.
It's so against what almosteveryone active in the
neurodiversity space stands for.
(09:21):
I don't support the search fortreatments or cures for autism.
I don't support researchers orresearch that claim in any way
to have autism eradication astheir goal.
But at the same time I need toreport on the research and I
find myself often having to makedo with what's there.
I think that's the case for alot of areas, not just autism
(09:43):
research.
The research on theseparticular topics is quite
different from other autismresearch I've been reading
lately, which has been quite abit more neurodiversity
affirming and where the writersand researchers worked hard to
challenge ableism witheverything they did, starting
from the actual research and theresearch questions and even the
(10:06):
composition of the researchteam, to the writing of their
research publications andconveying of their study results
.
So a lot of that research, notthe research I read for this
episode, but the other researchI'm talking about, I did notice
that a lot of their researchteams had autistic academics and
(10:27):
researchers or autistic clientsthat were part of the research
team.
I will say it was dishearteningto kind of feel like, with a lot
of the research I read for thisepisode in particular, I was
going back in time or readingregressive stances from those
who clearly hadn't worked toensure they're following current
best practice when it comes towriting about and researching
(10:50):
autism and autistic people.
It's unfortunate that theydon't seem to realize just how
many people they're alienatingwith their word choice and the
perspectives they're taking orallowing themselves to
uncritically fall into.
I guess the equivalent might bea study where they're
(11:11):
researching differences in thebrains of gay or queer people
versus the brains of straight ornon queer people and in
addition to objectively studyingthese differences, they oddly
also take a stance that beingqueer is not ideal or even that
there could one day be a cure orbrain based fix for being gay.
Now, that sounds obviouslyhorrible and absurd, right?
(11:34):
Well, it's also horrible andabsurd for it to be 2024 and
researchers and other expertsstill talking this way about
autism and being autistic, likeassuming we all want to be cured
or assuming that we wantinterventions that get rid of
our sorry, getting worked uphere and trying to destroy my
(11:55):
equipment.
Some people have challenged mebehind the scenes when I talk
this way, when I talk about thisstuff.
They say well, you'redismissing the autistic people
who suffer greatly because oftheir autism and who might want
some kind of intervention totake autistic symptoms or traits
away.
While I think my stance andresponse is still evolving,
(12:16):
especially in the way Iarticulate it, I will say that I
think that autistic people whowant a cure or intervention that
theoretically could take theirtraits away or greatly reduce
them have likely internalized avery negative, deficit based
view of autism.
I mean, it makes sense if yougrow up being told in both
(12:40):
direct and indirect waysconstantly that autistic traits
are inferior or undesirable andyou've never challenged these
perspectives for yourself orbeen able to, heck yes, you're
going to hold these sameperspectives.
Secondly, they likely haveco-occurring conditions, such as
(13:00):
intellectual disability orphysical disabilities that are
impacting them the most.
These folks typically havewhat's called a syndromic form
of autism, where the autism issecondary to a wider syndrome,
such as fragile X syndrome.
Some even question if it'saccurate to call these folks
(13:22):
autistic, because it's like theautism very much, it's
considered like secondary autism.
The autistic traits are not themain factor, are not the main
focus of the disorder.
So it might not even beaccurate to call those folks
autistic.
Someone with Rett syndrome orfragile X, are they autistic?
(13:45):
The jury, I think, is still outand I think more people are
raising the question like arethey?
I don't know if they'reautistic, should we be calling
them?
Should we be lumping them inwith the autistic community?
Because, as it stands, syndromicforms of autism account for
less than a quarter of theautistic population.
Non-syndromic autism, it's much, much more common, accounting
(14:10):
for over 75% of the autisticpopulation.
I think I've read higher, like80-85%.
To say it in another way, ifyou were to talk about cures for
the syndromic forms of autism,it would be targeting the
underlying factors leading totheir broader medical condition,
such as the genetic variants ormutations behind Rett syndrome,
(14:34):
R-E-T-T syndrome.
Autism or autistic traits thatcome with these syndromes are,
as I said before, consideredsecondary.
So why, I ask, are thesesyndromic forms of autism very
often treated as the predominantexperience of autistic people.
I don't discount theirexperiences or that their
(14:58):
medical challenges are moresevere, generally speaking, when
compared to non-syndromicautism.
But I want to make it clear aswell that we're talking about
very different conditions andvery vastly different
experiences.
I can say with confidence thatthe majority of autistic people
(15:21):
do not want you to even comenear them with any talk of cures
or autism interventions oranything of the sort.
So please think twice beforeassuming this is what we want or
assuming you know what's bestfor us.
We have the ability and theagency to speak for ourselves.
(15:44):
Shocking right?
No! Will all autistic peopleagree with the stance I've just
conveyed here?
Absolutely not.
I'm level one autistic with thenon-syndromic diagnosis of
autism and I'm one person.
So I definitely don't speak forothers on the spectrum and I
(16:05):
don't claim to even try to speakfor anyone else.
There's going to besimilarities, of course, like
there is with any human group,but I don't claim to be a voice
for the entire autisticpopulation, not even close.
Some people in our communitymight have zero problems with
deficit-based language anddeficit framing of autism.
(16:27):
Even my own language maintainssome of the deficit sort of
framing or talk, for example,when I use the word diagnosis or
when I say things like when Igot diagnosed as autistic.
It's very hard to talk aboutautism or autistic experience
without using at least some ofthis terminology.
(16:47):
I've talked about this atlength, but I think it's
important to continue to talkabout, especially as the
language has been and ischanging and continues to do so.
In my university, my degreeprogram, I found myself teaching
instructors and other students,even those who were quite up to
(17:11):
date in knowledge of the DSM,knowledge of psychology,
psychiatry, even those who claimknowledge of neurodevelopmental
conditions, were using thewrong language.
And I found myself having, theywanted evidence for why I kept
calling autistic people autisticinstead of saying person or
(17:33):
people with autism.
Part of what I studied and partof what I wrote about for
papers and even my lastmanuscript, my final manuscript,
had to do with autism-relatedtopics.
Instead of just being able toconcentrate on the research I
was doing and the work I wasdoing, I had to stop and
constantly explain myself.
(17:53):
Obviously, I don't think myclassmates and my instructors
were doing that on purpose, butit was exhausting.
They' d ask a question, they'dtry to challenge me, even though
they knew I was autistic,they'd challenge why I was using
that language and how it wasn'tappropriate.
I would give them things toread and they would still
(18:17):
clearly not go and read it andcontinue to challenge me.
I found myself having to dothat continually, over and over
and over again over the pastthree years.
I just found myself having tobe that person who has to teach
everyone about,almost the entire autistic
community prefers identity-firstlanguage instead of
(18:39):
person-first.
Why is it?
How many times do we have tosay that?
Do we have?
I don't know what it is withautistic folks being just like.
If I had a heart condition andI was trying to teach someone
about an aspect of the heartcondition, I wouldn't get this
(19:01):
much pushback.
It was disheartening,especially after seeing how much
work had been done withanti-racist sort of work and all
the EDI, equity, diversity,inclusion work that's going on
on campuses these days, to seethat neurodiversity, autistic
(19:22):
topics are kind of way down onthe list for most organizations.
I know for a fact that I'm notalone in having to be that
person who's like actually wedon't use that terminology
anymore and we haven't forliterally decades, so catch up,
(19:43):
please, it's not hard.
Anyway, that's sort of an aside, but I just had to share that.
To just say one more thingabout language, autism
scholarship has a long, longhistory of being firmly rooted
in the medical model.
All of the language that we useto talk about autism and
(20:05):
autistic people literally arosefrom the medical model.
The language surrounding autismwas born in that model and in
that world, that mindset.
So, it's going to be a process.
At the same time, thechallenging of the language, the
(20:26):
challenging of the medicalmodel, is really not that new.
It's relatively new, but I meanlike it started in the 60s and
the 70s.
And here we are and I'm stillhaving to make a case for why I,
an autistic person, am callingmyself autistic.
It's annoying.
(20:49):
That was a very long way tointroduce this topic and I think
it's time to talk about neuralpruning, neural N-E-U-R-A-L
pruning, and how that mightrelate to autism.
So any discussion about neuralpruning needs to start with talk
(21:10):
about the nervous system.
While there are several types ofcells in the nervous system,
there are two main cell types: neurons and glial cells. (21:16):
undefined
G-L-I-A-L, glial.
Neurons are the transmittingcells, or can be thought of as
conducting cells.
In the brain alone, there are86 billion neurons.
(21:37):
These neurons conduct or passinformation or signals to each
other, while glial cells can bethought of as, at least in part,
the connective tissue of thenervous system.
Glial cells are non-conductiveand provide structural and
nutritional support for theneurons.
They also include the immunecells of the nervous system, but
(22:01):
neurons will be our main focushere.
Importantly, the spaces betweenneurons, where information is
exchanged in the form ofsubstances called
neurotransmitters, are calledsynapses.
While we typically think of thebrain when we talk about
neurons, there are also synapsesbetween neurons and muscle
(22:21):
cells and neurons and glandcells.
Without these synapses, therewould be no information exchange
from one neuron to the next.
During a certain period of earlybrain development, from several
weeks after conception toaround eight months after birth,
there is a period of veryintense, very rapid synaptic
(22:43):
overgrowth, which is adorablyreferred to as exuberant
synaptogenesis.
Synaptogenesis here simplymeans the formation of synapses
between neurons.
There's kind of an explosion ofthese synapses, way more than
is necessary.
While synapses form throughouta person's life, they don't form
(23:08):
nearly as quickly orexuberantly as they do in this
critical period of earlydevelopment.
Then, around two years of age,something interesting happens,
and that is a period of rapidsynaptic pruning begins.
During synaptic pruning,synapses that are not used, or
(23:29):
not used very much, are simplydestroyed or removed.
It's thought that this is thebody's way of making sure that
brain function is efficient orstreamlined as we learn
increasingly more complicatedinformation and skills.
More efficient brain functionwould also mean faster brain
(23:50):
function.
The end result is a brain withboth fewer synapses, of course,
and fewer connections betweenbrain cells and brain regions.
Also, while very early synapticpruning shortly after birth is
thought to be influenced mainlyby genetics, a bit later on it's
mainly influenced by ourexperiences.
(24:12):
So the brain of a toddler who'sgetting read to a lot and who
has a lot of enrichingexperiences with toys that help
them learn and parents who arevery engaged in helping the
child learn and experience newthings, their brains are going
to be very different.
(24:32):
Their synapses are going to bevery different than a child who
lives in the opposite kind ofexperience or environment as
that.
The brain's going to prune verydifferently depending on their
experiences.
As Jacquelyn Cafasso says in anarticle for Healthline quote
(24:53):
whether or not a synapse ispruned is influenced by the
experiences a developing childhas with the world around them.
End quote.
Google (25:06):
Once the brain forms a synapse, it can either be
strengthened or weakened.
This depends on how often thesynapse is used.
In other words, the processfollows the use it or lose it
principle.
Synapses that are more activeare strengthened and synapses
that are less active areweakened and, ultimately, pruned
(25:26):
.
Kristen Hovet (25:28):
End quote.
I hope you got that, so it'sthe use it or lose it principle.
Also, she says synapse s weird.
Google (25:35):
Once the brain forms a synapse.
Kristen Hovet (25:38):
Synapse?
I guess I say synapse theBritish way, synapse, synapse,
weird.
Anyway, a significant body ofresearch has shown a link
between certain gene variantsrelated to synapses and synaptic
function and autism, and agrowing body of research has
(26:00):
appeared to confirm, somethrough postmortem studies, that
autistic individuals have moresynapses than their non-autistic
peers.
In other words, autisticindividuals' brains experience
reduced synaptic pruning.
At least that's what theresearch appears to be showing.
This means we have moreconnections between brain cells
(26:23):
and between various brainregions.
We have a whole whack ofexuberant synapses that refuse
to go gentle into that goodnight, to borrow a line from
poet Dylan Thomas.
Google (26:40):
This under pruning theory, may help explain some of
the common symptoms of autism,like oversensitivity to noise,
light, and social experiences,as well as epileptic seizures.
If there are too many synapsesfiring at once, a person with
autism will likely experience anoverload of noise.
Kristen Hovet (26:59):
End quote.
So our autistic brains retainquite a lot of extra or what a
lot of the research papers Iread call redundant connections
between neurons and brainregions.
But this word redundant soundsquite judgy to me and comes from
(27:22):
comparing said connections tothe fewer connections in the
non-autistic brain.
So obviously the research isbased on assumptions that the
neurotypical brain is the rightbrain, the proper brain, the
healthy brain, the brain that weshould all aspire to be.
But I think we need all thebrains.
(27:46):
I think we need all theautistic brains and the
non-autistic brains and we needto stop comparing everything to
the non-autistic brain, self,way, et cetera.
It's quite likely that thereduced synaptic pruning and the
resulting extra brainconnections explain why it
(28:08):
sometimes feels to me like Ineed to wait for signals to pass
through a literal tangle ofcognitive networks and also why
my brain sometimes feels on firewith all of the electrical
signals zooming around.
If you did a scan of my brainduring these moments, it would
probably look like it wasliterally on fire.
(28:31):
If this is all true, our brainsare working harder and messages
in our brains need to gothrough more channels, which
takes longer.
There's more processing to bedone.
Some have theorized that thisslower processing underlies our
tendency to think deeply, to bequote unquote intense, to think
(28:56):
outside the box, and to be moreinclined to take in a lot of
details, favoring details overbigger picture perspectives.
As Martin Silvertant states inan article for Embrace Autism,
the, quote, increasedcommunication between neurons
and particular pathways can leadto amazing abilities.
(29:19):
End quote.
For example, being an autisticsavant is likely linked with a
bunch of synapses that didn'tever get pruned away.
Also, synesthesia, known to bevery common in brains with
reduced synaptic pruning andvery common in autistics and
other neurodivergent individuals, is likely directly related to
(29:43):
increased brain connectivity.
Synesthesia is defined as aphenomenon where the activation
of one sensory or cognitivepathway triggers the activation
of one or more additionalsensory and or cognitive
pathways.
A person with synesthesia mightexperience colors when
(30:03):
listening to music, or theymight experience certain tastes
or smells when readingparticular words.
While only about 4% of thegeneral population experiences
synesthesia, almost a quarter ofthe autistic population does.
This percentage might actuallybe higher as the research grows
(30:26):
in this area.
It's very common for anautistic person to not even
realize they have synesthesia.
They might not know there'sanything different about their
experience and the way theyexperience reality, and so they
may assume that everyone has thesame experiences that we now
know to be synesthesia.
(30:46):
This is certainly the case withme, in that I thought everyone
has an explosion of sensory orcognitive experiences as a
result of specific perceptionsor thoughts.
Let me explain, because that allsounds pretty abstract.
But first, more lip gloss.
My lips are getting dry.
I don't know about you, but I'mone of those autistics that
(31:09):
always has to have something onmy lips and lotion on my hands.
I cannot handle dry hands.
I know that there's I haveautistic friends who are the
opposite.
They can't stand sticky lotionon their hands.
I don't like sticky lotion, butI need my hands moisturized at
all times, or I'm like I can'ttouch anything, my hands are dry
(31:29):
! I don't like dry lips either.
It's like I just get reallydistracted and all I think about
is hands! Or Lips.
So synesthesia.
I have mirror touch synesthesia, to give one example, which is
when you feel the same orsimilar sensations as another
person.
So if I see someone get hit inthe stomach, I'll literally feel
(31:53):
pain or a jolting sensation inmy own stomach.
This type of synesthesia, thismirror touch synesthesia, has
been associated with really highlevels of empathy compared to
the general population.
It might be that people who aredescribed as empaths simply
have mirror touch synesthesia,basically a bunch of extra
(32:17):
synaptic connections in thesomatosensory and mirror neuron
areas of their brain.
I also have misophonia, whichsome think is a form of
synesthesia.
Misophonia is when youexperience negative emotions or
states, such as a state of majorannoyance or the negative
(32:39):
emotions of anger, fear and ordisgust, when you hear certain
sounds or like certain words orsounds made in certain
frequencies.
So with me, when I hear peopleblowing in that raspberry sound,
like I can't even do it, it'sso, making that sputtery
spitting sound with their mouths, my brain just like feels like
(33:04):
someone's gripped it from theinside and is sort of like
rubbing it with steel wool orsomething.
I don't know how else todescribe it, and I feel like
this kind of, I guess, disgustwould be close to what I feel,
the same kind of likeheebie-jeebie feeling that some
(33:26):
people get with the nails onchalkboard thing.
So it's intensely unpleasantand like I just, if I'm around
other people and it happens, Ican sort of usually suppress my
response, my reaction, but I'mfeeling it and it's very
(33:46):
unpleasant.
I don't like it at all.
Like I literally can't make thesound to show you or play you
the sound because I edit my ownpodcast episodes.
I'd have to hear that back andI just I don't want to do that
to myself right now.
I don't want to put myselfthrough that.
It's not fun.
The other type of synesthesiathat I didn't even know was
synesthesia until I did thereading for this episode, it's
(34:09):
called number form synesthesia.
It's like a spatial form ofsynesthesia where you have like
a spatial sense of numbers orlike, as opposed to abstract.
Numbers are almost like aliteral map of numbers in your
brain, that kind of like appearin your mind as though your
(34:32):
perception or awareness is kindof focused into the middle of
the map that it's sort ofgenerating and other numbers
span to the left and to theright, into the distance and air
quotes, of course, on distancebecause it's in your mind, but
whatever, it's really hard toexplain.
(34:52):
So let's say, if I'm asked tothink about the year 1980,
numbers to the left are olderthan 1980, with the year like
1900 being more to the left thanlike the year 1940, which would
be like more here right.
(35:13):
1980, of course in the center,because I've been asked to think
about 1980 and numbers to theright being closer to now and
then spanning into the futurefurther right.
So it's like this very specificspatial orientation and it's
like almost literally every timeI'm asked to think about or I
need to think about a number.
(35:33):
I hope it makes sense and I'mwondering if you experienced
that, like does anyone else?
What's your synesthesia?
I think there's like 80 someodd kinds and they're still,
there's only been research kindof focused on a few, but more
research is being done, so it'spretty exciting.
Like many people withsynesthesia, we didn't, like I
(35:54):
said, know that our experiencesare different than others.
Like why would we know that?
Like if, unless it's somethingthat specifically talked about
quite early on in our lives.
We don't start learning aboutit until we're talking about
something related to synesthesiaand people react with shock or
confusion or even fear, likereally, what?
(36:16):
That's weird! That's so weird!I think the most shocking to me
personally was realizing thatmost people don't feel
sensations that mirror orreflect what others feel.
It's such a common experiencefor me and it's so core to my
experience of the world, ofothers, that I can't believe
(36:39):
that it isn't like human defaultmode.
I'm trying to understand howothers understand, because for
me it's like a physical thing.
I can understand, I canempathize, and I can feel what
you're feeling, because Iliterally feel what you're
feeling.
If you're describing it, if youare showing that you're feeling
(37:02):
something, let's say likeyou're doing this because your
shoulder hurts, so my shoulderwill start to feel weird or pain
.
Sometimes it's like what Iwould call a queasy sensation
that is like radiating from myshoulder.
Again, I know from talking toothers that this sounds very
(37:24):
strange and weird, but for manyof you, you'll be like yeah,
yeah, of course, obviously duh,like,
that's what I experience, too,and I know for some people this
mirror touch synesthesiaspecifically, is so strong that
it's almost hard to be aroundpeople because you're not only
(37:46):
feeling your own feels butyou're feeling the other
people's literal feels at thesame time and that's exhausting.
It's exhausting to feeleveryone's feels and I would say
mine is strong, but not strongto that degree.
I mean I do have to spend a lotof time on my own.
(38:07):
Maybe a lot of it is to do withthe mirror touch thing, but
because I think a lot of ithappens without me being
immediately aware, because it'sso, like I said, it's so core to
my experience of others that Idon't think I necessarily always
know that it's happening whenit's happening.
(38:27):
I kind of have to like take astep back and go what's this,
what's going on?
Oh yeah, this is my sensationand this here, that's your
sensation and I'm feeling it.
So it's, now my brain is goingoff into all these different
thoughts about how autisticfolks are impacted by these
(38:51):
various types of synesthesia andhow that is so core to what we
call, what some call symptoms,what I prefer to call traits,
autistic traits, that, um, yeah.
So to sum up this section onsynaptic pruning and synesthesia
(39:11):
, I really like Silvert ant'swords that with reduced synaptic
pruning, quote, society gainsan autistic person person in a
smaller number of cases, peoplewith synesthesia, and in rare
cases, a savant, end quote.
I really like that because it'ssort of a positive way of
(39:32):
seeing this and it's not like,oh darn, you have so many darn
synapses.
Ya poor thing, ya have billionsof synapses.
What ya gonna do?
It's like you are you in partbecause of all your lovely,
exuberant synapses and all thebeautiful brain fires that your
(39:58):
brain ignites and keeps theflame every single day.
That is awesome, that isbeautiful.
I like that.
I like that slant on it asopposed to.
I think I especially like itbecause I've had to read all the
very disappointing research onlike yeah, we know these changes
(40:20):
exist now, so maybe one day wecan develop a neurologically
based cure or intervention andjust zap, zap, zap.
No, thank you, I'm done withthat research for a while.
I don't want to read anythinglike that for a good long while
and I said I wasn't going to getinto the weeds and details.
(40:40):
But dang it.
Glial cells are interesting, andmicroglial microglia in
particular might be behind a lotof the differences in synaptic
pruning that are seen betweenautistic and non-autistic brains
.
So I can't help myself.
I'll talk a bit about it here.
But for any of you who areinterested in reading more about
(41:03):
microglia and autism, I'llinclude some interesting
articles in the show notes.
It includes work about glialcells called astrocytes, which
are beautiful.
As their name describes, astro,they're kind of like star
shaped and, of course, well, notof course, I'm looking it up on
my Merriam- Webster dictionaryapp.
(41:24):
Astro combining form fromastron, which means star,
borrowed from Greek, soastrocytes are these beautiful
star shaped cells in the brain.
And anyway, I'm going to stopthere before I go on another
tangent.
(41:45):
Microglial cells, or microglia,are the most abundant immune
cells in the central nervoussystem and they have the ability
to carry out phagocytosis, anamazing word.
Phagocytosis means that theycan eat, quote unquote eat, or
engulf dead cells or damagedcell components or parts that
(42:08):
form when the brain'sexperiencing inflammation, for
example.
Some of the components thatmicroglia can engulf include
weak or inactive synapses.
Hello, synaptic pruning.
This means that microglialcells need to be activated to
clear out underused or unusedsynapses in the developing brain
(42:31):
.
It could be that autisticbrains have differently
programmed, differentlybehaving, or differently shaped
or activated microglia,resulting in a different balance
between neuronal excitation orfiring, and neuronal inhibition
or ceasing to fire, whencompared to non-autistic brains.
(42:56):
The increased excitation theoryholds that autistic brains will
experience more excitation,more connectivity in key regions
of the brain, and this theoryis in part supported by the
known high rate of co-occurrencebetween autism and epilepsy and
(43:17):
autism and seizure disorders.
Neuronal hyperactivity orhyperexcitability underlie
epilepsy and seizures, sothere's a lot of overlap there.
Some research has shown thatsome autistic brains have an
increase in brain cell activityin some brain regions, while
(43:40):
having a decrease in brain cellactivity in other regions.
This balance of neuronalexcitation and inhibition seems
to vary from one autistic personto the next, so it could be
that the only thing we might beable to say for sure at this
point in time is that autisticbrains are characterized by
(44:01):
marked differences in thebalance of excitation and
inhibition of neurons comparedto non-autistic brains, and that
we also have more synapses.
That seems pretty clear.
However, more research isneeded to really determine the
details of these differences.
That is where I'd like to end,because I feel like I could just
(44:23):
keep talking.
I really like this topic and Ido want to hear from you.
Synesthesia is a very new wordin my vocabulary.
I have known about it for acouple years now, but it was
like a huge epiphany when Ifirst learned about it and when
I learned that it's not the norm.
(44:45):
I also see colors withdifferent numbers and I thought
that that was because of how Ilearned to count.
We had this like penny systemwhere pennies, circles were
drawn with pennies, and that'swhy they called it the penny
system.
So they would have these chartsshowing the numbers and they
would take a penny and drawcircles over the numbers, so
like the number two had twocircles, so you'd have this like
(45:09):
image in your brain, at least Idid very much, like the number
two always has two dots and eachnumber has a color.
And I don't know if that's mybrain doing synesthesia stuff or
if it's because when I learnedthe numbers, they were on these
colored charts and they werealmost permanently attached to
the wall in elementary school,and so I'm not sure if my brain
(45:31):
is just applying the colors ofthat chart or if I literally, if
it's a synesthesia thing.
Like I can't think of certainnumbers without also feeling,
sensing a color to go with it.
And I just thought that thatwas normal.
Like how else would I knowunless, like there's so many
(45:52):
things that we think and feeland process that we don't ever
talk about and that they almostcome out accidentally.
And you might be talking aboutit one day and someone goes, huh
, no, that's not what Iexperience, or whatever, and so
you learn about it in theseweird moments and then to find
out later it has a name.
(46:13):
So I'm not, I'm not weird.
Likethis is something that is normal
for our community.
Some of it's very beautiful,like I saw someone on social
media who's autistic, who yougive them your name and they
come up with like this beautiful, like they have this beautiful
almost like rainbow in theirhead of different colors, that
(46:35):
matches each person's name, orlike with a predominant color.
So I think my name has purplein it.
Yay, I love purple! But forthat person, like for another
person, it might be a totallydifferent color scheme, but I
just think that's beautiful, tolike have this parade of colors
that come along with language,like that's beautiful.
(46:57):
I have it with numbers andthey're kind of not exciting
colors and like it's primarycolors, which makes me think
it's just from elementary schooldays.
But anyway, I'd love to hearyour experience of synesthesia.
I don't know if I'm saying itright again.
Like, help me Google.
Synesthesia.
What is it in Romanian?
Google (47:20):
Sinestezie.
Kristen Hovet (47:22):
Nice.
Norwegian! Synestesi.
I like that one.
Okay, well, that's all I havefor you today.
Speaker 3 (47:43):
Thank you so much for being here.
Until next time, bye.
Hey everyone, my name is Kristen Hovet.
Welcome back to The OtherAutism podcast.
Today we're talking aboutneural pruning and how it
differs in the brains ofautistics versus the brains of
neurotypicals.
I'll also discuss synesthesia.
I don't know if I'm saying thatright.
I'm saying it.
I think I tried getting GoogleTranslate to help me and I'm
(00:23):
still not saying it right.
So, actually, speaking ofGoogle Translate, I think she's
going to help me in this episode, so I'm going to need her here.
One sec, okay, synesthesia.
Synesthesia, yeah, where onesensory or cognitive pathway
activates a second or maybe eventhird sensory or cognitive
(00:46):
pathway.
But before we get into all ofthat, I wanted to say sorry for
the long gap of time betweenthis episode today and the last
one in November.
So a lot has happened betweenNovember and today, which is
January 21st.
I did have an interview linedup for December and we had to
(01:08):
cancel it last minute and thenholiday rush began, so I didn't
have time to set up somethingelse.
And there's other reasons too.
I probably could have fitsomething in there if I was at
my usual healthy, energized kindof self.
So I finished my Master ofHealth Studies degree with a
(01:32):
major in health research inDecember, then went away for a
while for the holidays, then Igot sick a few times and now I'm
back.
So my degree, as some of youknow, took three years to
complete.
I was considered a full timeMaster's student and I was also
working for most of that workingfull time at the same time.
(01:55):
It would have taken me fouryears in the program I was in,
but I did have some Master'slevel classes under my belt from
before I had cancer, before Iwas diagnosed with cancer, when
I was still pursuing a Master'sin counseling psychology.
I got to use those classestowards my degree, thankfully.
(02:16):
Anyway, the last three yearshave been a lot.
It's been a lot of really goodthings and a lot of very
challenging things.
Also,so while I was in school and
working, I went through the endof an almost 12 year long
relationship that upendedeverything, including, I mean,
(02:39):
that has an impact on your self-concept.
It has an impact on how youspend your time and it leads to
a sort of having to likereadjust everything, your
schedule, how you spend yourfree time.
It impacts everything.
So I went through the end ofthat and, about a year and a
(03:01):
half after that, the beginningof an amazing new relationship.
I also worked through griefrelated to the loss of my
brother and the loss of a friend.
Not to mention, I moved twicein the past two years alone.
And then, when I moved to mycurrent place here, I got
(03:22):
evacuated from fires this pastsummer, so that was literally
like a couple months after Imoved.
It's like, now you have to runaway from fire and you have to
stay out of your house for aweek, and I was lucky that I had
a place to stay, because noteveryone was so fortunate and
some people lost their homes.
That was terrifying and I sortof just kept trucking along.
(03:48):
I got back home and just kindof almost tried to forget that
that all had happened, becauseit was just like, really like,
really, you're gonna, this isgonna be what's happening right
now.
So anyway, on top of all of that, there was significant work
related stress that I've beendealing with off and on, I would
say, for a long time, and Ienjoy my work, but there are
(04:11):
some stressful elements.
And I think all of it justfinally caught up with me.
I have a lot of things in placeto sort of like deal with
impacts of stress and deal withimpacts of challenging life
events happening, but it's likeall of those, those resources
(04:33):
and things I have in place werenot enough, I don't think, and
it all just kind of caught upand I was just blindsided by the
after effects, all of a sudden.
I found myself pretty burnt out, despite, like I said, so many
good things going on and so manyelements that bring resilience
(04:56):
to my life, like, I thinkinternal elements and also
support system outside of myself.
I also have, like I stick to apretty clear routine, a pretty
strict sleep schedule, all thesethings that I know to help
myself.
It was just not enough and whathappened was like I've
(05:17):
experienced burnout before,which I did talk about,
ironically, last couple episodesago.
I was talking about burnout.
If you heard that one, you knowthat I've experienced burnout
before, and this one was like itcame up very, very slowly and
then it just knocked me off myfeet.
What happened was I was able toevery day, get through the
(05:39):
workday, do my work, concentrateon work, and after that, when I
would normally do some errandsand then work on a podcast or do
something like that, I couldn'tdo anything else for the rest
of the day other than washingdishes and vacuuming and then
playing with my cat and thenwatching TV.
(06:01):
Like I really, I had zeroenergy for anything more,
unfortunately, and there were somany things I wanted to do with
the podcast and so many emailsI wanted to respond to and I
just.
I appreciate that several ofyou took the time to check in
and I fairly confidently can sayI'm back.
(06:25):
I don't know if I'm going to beable to keep up the two or
three episodes a month.
We'll see.
Ideally, as I've said before, Iwould love to have The Other
Autism be my full-time job.
That is my dream.
Unfortunately, I'm not quiteclose there yet.
I don't know if a lot of youknow, but to be part of the
(06:48):
bigger advertising groups or toget in on the bigger advertising
that podcasts do, you have tohave 10,000 listens per episode,
to even sign up for a lot ofthose.
Actually, most of them havesome very strict guidelines like
that and I'm not quite thereyet for that many per episode.
(07:13):
But that's my goal to get thereand to be able to give you more
content, more interviews, anddo a lot of other things.
It's my goal, my dream, to beable to do that.
I felt like this was asignificant stumbling block this
past couple months and I reallydon't want it to happen again.
(07:35):
I can't promise that it won't,but I don't foresee all the
things that happened in the lastfew years happening ever again
to me.
Knock on wood.
But I don't foresee all ofthose things happening again or
happening in such quicksuccession, one after the other,
(07:57):
the way that they have.
I could have chosen an easiersubject for myself, in the face
of burnout especially, but onceI started reading about it, I
knew I had to do this episodeand I knew it had to be the
first one of 2024.
The topics I'm going to covertoday are, as I said, not easy.
For that reason, I'm going totry to take it slow and break
(08:19):
things down without getting toodeeply into the weeds or the
unnecessary details.
I think it's important, too,since the research is still
underway in this area, to keepthings a bit high level, and
what I mean by high level hereis that I'll try to stick to
more general summaries asopposed to getting into the
(08:40):
minute biological, neurologicaldetails.
I also wanted to mention that Iwas a bit disturbed while I was
reading the research on theseneurological, brain-based
aspects of autism.
I found that the language usedin a lot, not all, but a lot of
the content was quite in linewith the deficit model of autism
(09:00):
and a lot of it seemed focusedon like oh, if we understand
these neurological differencesin autistic brains, then one day
we might be able to fix them.
I just want to say that's soagainst what I stand for.
It's so against what almosteveryone active in the
neurodiversity space stands for.
(09:21):
I don't support the search fortreatments or cures for autism.
I don't support researchers orresearch that claim in any way
to have autism eradication astheir goal.
But at the same time I need toreport on the research and I
find myself often having to makedo with what's there.
I think that's the case for alot of areas, not just autism
(09:43):
research.
The research on theseparticular topics is quite
different from other autismresearch I've been reading
lately, which has been quite abit more neurodiversity
affirming and where the writersand researchers worked hard to
challenge ableism witheverything they did, starting
from the actual research and theresearch questions and even the
(10:06):
composition of the researchteam, to the writing of their
research publications andconveying of their study results
.
So a lot of that research, notthe research I read for this
episode, but the other researchI'm talking about, I did notice
that a lot of their researchteams had autistic academics and
(10:27):
researchers or autistic clientsthat were part of the research
team.
I will say it was dishearteningto kind of feel like, with a lot
of the research I read for thisepisode in particular, I was
going back in time or readingregressive stances from those
who clearly hadn't worked toensure they're following current
best practice when it comes towriting about and researching
(10:50):
autism and autistic people.
It's unfortunate that theydon't seem to realize just how
many people they're alienatingwith their word choice and the
perspectives they're taking orallowing themselves to
uncritically fall into.
I guess the equivalent might bea study where they're
(11:11):
researching differences in thebrains of gay or queer people
versus the brains of straight ornon queer people and in
addition to objectively studyingthese differences, they oddly
also take a stance that beingqueer is not ideal or even that
there could one day be a cure orbrain based fix for being gay.
Now, that sounds obviouslyhorrible and absurd, right?
(11:34):
Well, it's also horrible andabsurd for it to be 2024 and
researchers and other expertsstill talking this way about
autism and being autistic, likeassuming we all want to be cured
or assuming that we wantinterventions that get rid of
our sorry, getting worked uphere and trying to destroy my
(11:55):
equipment.
Some people have challenged mebehind the scenes when I talk
this way, when I talk about thisstuff.
They say well, you'redismissing the autistic people
who suffer greatly because oftheir autism and who might want
some kind of intervention totake autistic symptoms or traits
away.
While I think my stance andresponse is still evolving,
(12:16):
especially in the way Iarticulate it, I will say that I
think that autistic people whowant a cure or intervention that
theoretically could take theirtraits away or greatly reduce
them have likely internalized avery negative, deficit based
view of autism.
I mean, it makes sense if yougrow up being told in both
(12:40):
direct and indirect waysconstantly that autistic traits
are inferior or undesirable andyou've never challenged these
perspectives for yourself orbeen able to, heck yes, you're
going to hold these sameperspectives.
Secondly, they likely haveco-occurring conditions, such as
(13:00):
intellectual disability orphysical disabilities that are
impacting them the most.
These folks typically havewhat's called a syndromic form
of autism, where the autism issecondary to a wider syndrome,
such as fragile X syndrome.
Some even question if it'saccurate to call these folks
(13:22):
autistic, because it's like theautism very much, it's
considered like secondary autism.
The autistic traits are not themain factor, are not the main
focus of the disorder.
So it might not even beaccurate to call those folks
autistic.
Someone with Rett syndrome orfragile X, are they autistic?
(13:45):
The jury, I think, is still outand I think more people are
raising the question like arethey?
I don't know if they'reautistic, should we be calling
them?
Should we be lumping them inwith the autistic community?
Because, as it stands, syndromicforms of autism account for
less than a quarter of theautistic population.
Non-syndromic autism, it's much, much more common, accounting
(14:10):
for over 75% of the autisticpopulation.
I think I've read higher, like80-85%.
To say it in another way, ifyou were to talk about cures for
the syndromic forms of autism,it would be targeting the
underlying factors leading totheir broader medical condition,
such as the genetic variants ormutations behind Rett syndrome,
(14:34):
R-E-T-T syndrome.
Autism or autistic traits thatcome with these syndromes are,
as I said before, consideredsecondary.
So why, I ask, are thesesyndromic forms of autism very
often treated as the predominantexperience of autistic people.
I don't discount theirexperiences or that their
(14:58):
medical challenges are moresevere, generally speaking, when
compared to non-syndromicautism.
But I want to make it clear aswell that we're talking about
very different conditions andvery vastly different
experiences.
I can say with confidence thatthe majority of autistic people
(15:21):
do not want you to even comenear them with any talk of cures
or autism interventions oranything of the sort.
So please think twice beforeassuming this is what we want or
assuming you know what's bestfor us.
We have the ability and theagency to speak for ourselves.
(15:44):
Shocking right?
No! Will all autistic peopleagree with the stance I've just
conveyed here?
Absolutely not.
I'm level one autistic with thenon-syndromic diagnosis of
autism and I'm one person.
So I definitely don't speak forothers on the spectrum and I
(16:05):
don't claim to even try to speakfor anyone else.
There's going to besimilarities, of course, like
there is with any human group,but I don't claim to be a voice
for the entire autisticpopulation, not even close.
Some people in our communitymight have zero problems with
deficit-based language anddeficit framing of autism.
(16:27):
Even my own language maintainssome of the deficit sort of
framing or talk, for example,when I use the word diagnosis or
when I say things like when Igot diagnosed as autistic.
It's very hard to talk aboutautism or autistic experience
without using at least some ofthis terminology.
(16:47):
I've talked about this atlength, but I think it's
important to continue to talkabout, especially as the
language has been and ischanging and continues to do so.
In my university, my degreeprogram, I found myself teaching
instructors and other students,even those who were quite up to
(17:11):
date in knowledge of the DSM,knowledge of psychology,
psychiatry, even those who claimknowledge of neurodevelopmental
conditions, were using thewrong language.
And I found myself having, theywanted evidence for why I kept
calling autistic people autisticinstead of saying person or
(17:33):
people with autism.
Part of what I studied and partof what I wrote about for
papers and even my lastmanuscript, my final manuscript,
had to do with autism-relatedtopics.
Instead of just being able toconcentrate on the research I
was doing and the work I wasdoing, I had to stop and
constantly explain myself.
(17:53):
Obviously, I don't think myclassmates and my instructors
were doing that on purpose, butit was exhausting.
They' d ask a question, they'dtry to challenge me, even though
they knew I was autistic,they'd challenge why I was using
that language and how it wasn'tappropriate.
I would give them things toread and they would still
(18:17):
clearly not go and read it andcontinue to challenge me.
I found myself having to dothat continually, over and over
and over again over the pastthree years.
I just found myself having tobe that person who has to teach
everyone about,almost the entire autistic
community prefers identity-firstlanguage instead of
(18:39):
person-first.
Why is it?
How many times do we have tosay that?
Do we have?
I don't know what it is withautistic folks being just like.
If I had a heart condition andI was trying to teach someone
about an aspect of the heartcondition, I wouldn't get this
(19:01):
much pushback.
It was disheartening,especially after seeing how much
work had been done withanti-racist sort of work and all
the EDI, equity, diversity,inclusion work that's going on
on campuses these days, to seethat neurodiversity, autistic
(19:22):
topics are kind of way down onthe list for most organizations.
I know for a fact that I'm notalone in having to be that
person who's like actually wedon't use that terminology
anymore and we haven't forliterally decades, so catch up,
(19:43):
please, it's not hard.
Anyway, that's sort of an aside, but I just had to share that.
To just say one more thingabout language, autism
scholarship has a long, longhistory of being firmly rooted
in the medical model.
All of the language that we useto talk about autism and
(20:05):
autistic people literally arosefrom the medical model.
The language surrounding autismwas born in that model and in
that world, that mindset.
So, it's going to be a process.
At the same time, thechallenging of the language, the
(20:26):
challenging of the medicalmodel, is really not that new.
It's relatively new, but I meanlike it started in the 60s and
the 70s.
And here we are and I'm stillhaving to make a case for why I,
an autistic person, am callingmyself autistic.
It's annoying.
(20:49):
That was a very long way tointroduce this topic and I think
it's time to talk about neuralpruning, neural N-E-U-R-A-L
pruning, and how that mightrelate to autism.
So any discussion about neuralpruning needs to start with talk
(21:10):
about the nervous system.
While there are several types ofcells in the nervous system,
there are two main cell types: neurons and glial cells. (21:16):
undefined
G-L-I-A-L, glial.
Neurons are the transmittingcells, or can be thought of as
conducting cells.
In the brain alone, there are86 billion neurons.
(21:37):
These neurons conduct or passinformation or signals to each
other, while glial cells can bethought of as, at least in part,
the connective tissue of thenervous system.
Glial cells are non-conductiveand provide structural and
nutritional support for theneurons.
They also include the immunecells of the nervous system, but
(22:01):
neurons will be our main focushere.
Importantly, the spaces betweenneurons, where information is
exchanged in the form ofsubstances called
neurotransmitters, are calledsynapses.
While we typically think of thebrain when we talk about
neurons, there are also synapsesbetween neurons and muscle
(22:21):
cells and neurons and glandcells.
Without these synapses, therewould be no information exchange
from one neuron to the next.
During a certain period of earlybrain development, from several
weeks after conception toaround eight months after birth,
there is a period of veryintense, very rapid synaptic
(22:43):
overgrowth, which is adorablyreferred to as exuberant
synaptogenesis.
Synaptogenesis here simplymeans the formation of synapses
between neurons.
There's kind of an explosion ofthese synapses, way more than
is necessary.
While synapses form throughouta person's life, they don't form
(23:08):
nearly as quickly orexuberantly as they do in this
critical period of earlydevelopment.
Then, around two years of age,something interesting happens,
and that is a period of rapidsynaptic pruning begins.
During synaptic pruning,synapses that are not used, or
(23:29):
not used very much, are simplydestroyed or removed.
It's thought that this is thebody's way of making sure that
brain function is efficient orstreamlined as we learn
increasingly more complicatedinformation and skills.
More efficient brain functionwould also mean faster brain
(23:50):
function.
The end result is a brain withboth fewer synapses, of course,
and fewer connections betweenbrain cells and brain regions.
Also, while very early synapticpruning shortly after birth is
thought to be influenced mainlyby genetics, a bit later on it's
mainly influenced by ourexperiences.
(24:12):
So the brain of a toddler who'sgetting read to a lot and who
has a lot of enrichingexperiences with toys that help
them learn and parents who arevery engaged in helping the
child learn and experience newthings, their brains are going
to be very different.
(24:32):
Their synapses are going to bevery different than a child who
lives in the opposite kind ofexperience or environment as
that.
The brain's going to prune verydifferently depending on their
experiences.
As Jacquelyn Cafasso says in anarticle for Healthline quote
(24:53):
whether or not a synapse ispruned is influenced by the
experiences a developing childhas with the world around them.
End quote.
Google (25:06):
Once the brain forms a synapse, it can either be
strengthened or weakened.
This depends on how often thesynapse is used.
In other words, the processfollows the use it or lose it
principle.
Synapses that are more activeare strengthened and synapses
that are less active areweakened and, ultimately, pruned
(25:26):
.
Kristen Hovet (25:28):
End quote.
I hope you got that, so it'sthe use it or lose it principle.
Also, she says synapse s weird.
Google (25:35):
Once the brain forms a synapse.
Kristen Hovet (25:38):
Synapse?
I guess I say synapse theBritish way, synapse, synapse,
weird.
Anyway, a significant body ofresearch has shown a link
between certain gene variantsrelated to synapses and synaptic
function and autism, and agrowing body of research has
(26:00):
appeared to confirm, somethrough postmortem studies, that
autistic individuals have moresynapses than their non-autistic
peers.
In other words, autisticindividuals' brains experience
reduced synaptic pruning.
At least that's what theresearch appears to be showing.
This means we have moreconnections between brain cells
(26:23):
and between various brainregions.
We have a whole whack ofexuberant synapses that refuse
to go gentle into that goodnight, to borrow a line from
poet Dylan Thomas.
Google (26:40):
This under pruning theory, may help explain some of
the common symptoms of autism,like oversensitivity to noise,
light, and social experiences,as well as epileptic seizures.
If there are too many synapsesfiring at once, a person with
autism will likely experience anoverload of noise.
Kristen Hovet (26:59):
End quote.
So our autistic brains retainquite a lot of extra or what a
lot of the research papers Iread call redundant connections
between neurons and brainregions.
But this word redundant soundsquite judgy to me and comes from
(27:22):
comparing said connections tothe fewer connections in the
non-autistic brain.
So obviously the research isbased on assumptions that the
neurotypical brain is the rightbrain, the proper brain, the
healthy brain, the brain that weshould all aspire to be.
But I think we need all thebrains.
(27:46):
I think we need all theautistic brains and the
non-autistic brains and we needto stop comparing everything to
the non-autistic brain, self,way, et cetera.
It's quite likely that thereduced synaptic pruning and the
resulting extra brainconnections explain why it
(28:08):
sometimes feels to me like Ineed to wait for signals to pass
through a literal tangle ofcognitive networks and also why
my brain sometimes feels on firewith all of the electrical
signals zooming around.
If you did a scan of my brainduring these moments, it would
probably look like it wasliterally on fire.
(28:31):
If this is all true, our brainsare working harder and messages
in our brains need to gothrough more channels, which
takes longer.
There's more processing to bedone.
Some have theorized that thisslower processing underlies our
tendency to think deeply, to bequote unquote intense, to think
(28:56):
outside the box, and to be moreinclined to take in a lot of
details, favoring details overbigger picture perspectives.
As Martin Silvertant states inan article for Embrace Autism,
the, quote, increasedcommunication between neurons
and particular pathways can leadto amazing abilities.
(29:19):
End quote.
For example, being an autisticsavant is likely linked with a
bunch of synapses that didn'tever get pruned away.
Also, synesthesia, known to bevery common in brains with
reduced synaptic pruning andvery common in autistics and
other neurodivergent individuals, is likely directly related to
(29:43):
increased brain connectivity.
Synesthesia is defined as aphenomenon where the activation
of one sensory or cognitivepathway triggers the activation
of one or more additionalsensory and or cognitive
pathways.
A person with synesthesia mightexperience colors when
(30:03):
listening to music, or theymight experience certain tastes
or smells when readingparticular words.
While only about 4% of thegeneral population experiences
synesthesia, almost a quarter ofthe autistic population does.
This percentage might actuallybe higher as the research grows
(30:26):
in this area.
It's very common for anautistic person to not even
realize they have synesthesia.
They might not know there'sanything different about their
experience and the way theyexperience reality, and so they
may assume that everyone has thesame experiences that we now
know to be synesthesia.
(30:46):
This is certainly the case withme, in that I thought everyone
has an explosion of sensory orcognitive experiences as a
result of specific perceptionsor thoughts.
Let me explain, because that allsounds pretty abstract.
But first, more lip gloss.
My lips are getting dry.
I don't know about you, but I'mone of those autistics that
(31:09):
always has to have something onmy lips and lotion on my hands.
I cannot handle dry hands.
I know that there's I haveautistic friends who are the
opposite.
They can't stand sticky lotionon their hands.
I don't like sticky lotion, butI need my hands moisturized at
all times, or I'm like I can'ttouch anything, my hands are dry
(31:29):
! I don't like dry lips either.
It's like I just get reallydistracted and all I think about
is hands! Or Lips.
So synesthesia.
I have mirror touch synesthesia, to give one example, which is
when you feel the same orsimilar sensations as another
person.
So if I see someone get hit inthe stomach, I'll literally feel
(31:53):
pain or a jolting sensation inmy own stomach.
This type of synesthesia, thismirror touch synesthesia, has
been associated with really highlevels of empathy compared to
the general population.
It might be that people who aredescribed as empaths simply
have mirror touch synesthesia,basically a bunch of extra
(32:17):
synaptic connections in thesomatosensory and mirror neuron
areas of their brain.
I also have misophonia, whichsome think is a form of
synesthesia.
Misophonia is when youexperience negative emotions or
states, such as a state of majorannoyance or the negative
(32:39):
emotions of anger, fear and ordisgust, when you hear certain
sounds or like certain words orsounds made in certain
frequencies.
So with me, when I hear peopleblowing in that raspberry sound,
like I can't even do it, it'sso, making that sputtery
spitting sound with their mouths, my brain just like feels like
(33:04):
someone's gripped it from theinside and is sort of like
rubbing it with steel wool orsomething.
I don't know how else todescribe it, and I feel like
this kind of, I guess, disgustwould be close to what I feel,
the same kind of likeheebie-jeebie feeling that some
(33:26):
people get with the nails onchalkboard thing.
So it's intensely unpleasantand like I just, if I'm around
other people and it happens, Ican sort of usually suppress my
response, my reaction, but I'mfeeling it and it's very
(33:46):
unpleasant.
I don't like it at all.
Like I literally can't make thesound to show you or play you
the sound because I edit my ownpodcast episodes.
I'd have to hear that back andI just I don't want to do that
to myself right now.
I don't want to put myselfthrough that.
It's not fun.
The other type of synesthesiathat I didn't even know was
synesthesia until I did thereading for this episode, it's
(34:09):
called number form synesthesia.
It's like a spatial form ofsynesthesia where you have like
a spatial sense of numbers orlike, as opposed to abstract.
Numbers are almost like aliteral map of numbers in your
brain, that kind of like appearin your mind as though your
(34:32):
perception or awareness is kindof focused into the middle of
the map that it's sort ofgenerating and other numbers
span to the left and to theright, into the distance and air
quotes, of course, on distancebecause it's in your mind, but
whatever, it's really hard toexplain.
(34:52):
So let's say, if I'm asked tothink about the year 1980,
numbers to the left are olderthan 1980, with the year like
1900 being more to the left thanlike the year 1940, which would
be like more here right.
(35:13):
1980, of course in the center,because I've been asked to think
about 1980 and numbers to theright being closer to now and
then spanning into the futurefurther right.
So it's like this very specificspatial orientation and it's
like almost literally every timeI'm asked to think about or I
need to think about a number.
(35:33):
I hope it makes sense and I'mwondering if you experienced
that, like does anyone else?
What's your synesthesia?
I think there's like 80 someodd kinds and they're still,
there's only been research kindof focused on a few, but more
research is being done, so it'spretty exciting.
Like many people withsynesthesia, we didn't, like I
(35:54):
said, know that our experiencesare different than others.
Like why would we know that?
Like if, unless it's somethingthat specifically talked about
quite early on in our lives.
We don't start learning aboutit until we're talking about
something related to synesthesiaand people react with shock or
confusion or even fear, likereally, what?
(36:16):
That's weird! That's so weird!I think the most shocking to me
personally was realizing thatmost people don't feel
sensations that mirror orreflect what others feel.
It's such a common experiencefor me and it's so core to my
experience of the world, ofothers, that I can't believe
(36:39):
that it isn't like human defaultmode.
I'm trying to understand howothers understand, because for
me it's like a physical thing.
I can understand, I canempathize, and I can feel what
you're feeling, because Iliterally feel what you're
feeling.
If you're describing it, if youare showing that you're feeling
(37:02):
something, let's say likeyou're doing this because your
shoulder hurts, so my shoulderwill start to feel weird or pain
.
Sometimes it's like what Iwould call a queasy sensation
that is like radiating from myshoulder.
Again, I know from talking toothers that this sounds very
(37:24):
strange and weird, but for manyof you, you'll be like yeah,
yeah, of course, obviously duh,like,
that's what I experience, too,and I know for some people this
mirror touch synesthesiaspecifically, is so strong that
it's almost hard to be aroundpeople because you're not only
(37:46):
feeling your own feels butyou're feeling the other
people's literal feels at thesame time and that's exhausting.
It's exhausting to feeleveryone's feels and I would say
mine is strong, but not strongto that degree.
I mean I do have to spend a lotof time on my own.
(38:07):
Maybe a lot of it is to do withthe mirror touch thing, but
because I think a lot of ithappens without me being
immediately aware, because it'sso, like I said, it's so core to
my experience of others that Idon't think I necessarily always
know that it's happening whenit's happening.
(38:27):
I kind of have to like take astep back and go what's this,
what's going on?
Oh yeah, this is my sensationand this here, that's your
sensation and I'm feeling it.
So it's, now my brain is goingoff into all these different
thoughts about how autisticfolks are impacted by these
(38:51):
various types of synesthesia andhow that is so core to what we
call, what some call symptoms,what I prefer to call traits,
autistic traits, that, um, yeah.
So to sum up this section onsynaptic pruning and synesthesia
(39:11):
, I really like Silvert ant'swords that with reduced synaptic
pruning, quote, society gainsan autistic person person in a
smaller number of cases, peoplewith synesthesia, and in rare
cases, a savant, end quote.
I really like that because it'ssort of a positive way of
(39:32):
seeing this and it's not like,oh darn, you have so many darn
synapses.
Ya poor thing, ya have billionsof synapses.
What ya gonna do?
It's like you are you in partbecause of all your lovely,
exuberant synapses and all thebeautiful brain fires that your
(39:58):
brain ignites and keeps theflame every single day.
That is awesome, that isbeautiful.
I like that.
I like that slant on it asopposed to.
I think I especially like itbecause I've had to read all the
very disappointing research onlike yeah, we know these changes
(40:20):
exist now, so maybe one day wecan develop a neurologically
based cure or intervention andjust zap, zap, zap.
No, thank you, I'm done withthat research for a while.
I don't want to read anythinglike that for a good long while
and I said I wasn't going to getinto the weeds and details.
(40:40):
But dang it.
Glial cells are interesting, andmicroglial microglia in
particular might be behind a lotof the differences in synaptic
pruning that are seen betweenautistic and non-autistic brains
.
So I can't help myself.
I'll talk a bit about it here.
But for any of you who areinterested in reading more about
(41:03):
microglia and autism, I'llinclude some interesting
articles in the show notes.
It includes work about glialcells called astrocytes, which
are beautiful.
As their name describes, astro,they're kind of like star
shaped and, of course, well, notof course, I'm looking it up on
my Merriam- Webster dictionaryapp.
(41:24):
Astro combining form fromastron, which means star,
borrowed from Greek, soastrocytes are these beautiful
star shaped cells in the brain.
And anyway, I'm going to stopthere before I go on another
tangent.
(41:45):
Microglial cells, or microglia,are the most abundant immune
cells in the central nervoussystem and they have the ability
to carry out phagocytosis, anamazing word.
Phagocytosis means that theycan eat, quote unquote eat, or
engulf dead cells or damagedcell components or parts that
(42:08):
form when the brain'sexperiencing inflammation, for
example.
Some of the components thatmicroglia can engulf include
weak or inactive synapses.
Hello, synaptic pruning.
This means that microglialcells need to be activated to
clear out underused or unusedsynapses in the developing brain
(42:31):
.
It could be that autisticbrains have differently
programmed, differentlybehaving, or differently shaped
or activated microglia,resulting in a different balance
between neuronal excitation orfiring, and neuronal inhibition
or ceasing to fire, whencompared to non-autistic brains.
(42:56):
The increased excitation theoryholds that autistic brains will
experience more excitation,more connectivity in key regions
of the brain, and this theoryis in part supported by the
known high rate of co-occurrencebetween autism and epilepsy and
(43:17):
autism and seizure disorders.
Neuronal hyperactivity orhyperexcitability underlie
epilepsy and seizures, sothere's a lot of overlap there.
Some research has shown thatsome autistic brains have an
increase in brain cell activityin some brain regions, while
(43:40):
having a decrease in brain cellactivity in other regions.
This balance of neuronalexcitation and inhibition seems
to vary from one autistic personto the next, so it could be
that the only thing we might beable to say for sure at this
point in time is that autisticbrains are characterized by
(44:01):
marked differences in thebalance of excitation and
inhibition of neurons comparedto non-autistic brains, and that
we also have more synapses.
That seems pretty clear.
However, more research isneeded to really determine the
details of these differences.
That is where I'd like to end,because I feel like I could just
(44:23):
keep talking.
I really like this topic and Ido want to hear from you.
Synesthesia is a very new wordin my vocabulary.
I have known about it for acouple years now, but it was
like a huge epiphany when Ifirst learned about it and when
I learned that it's not the norm.
(44:45):
I also see colors withdifferent numbers and I thought
that that was because of how Ilearned to count.
We had this like penny systemwhere pennies, circles were
drawn with pennies, and that'swhy they called it the penny
system.
So they would have these chartsshowing the numbers and they
would take a penny and drawcircles over the numbers, so
like the number two had twocircles, so you'd have this like
(45:09):
image in your brain, at least Idid very much, like the number
two always has two dots and eachnumber has a color.
And I don't know if that's mybrain doing synesthesia stuff or
if it's because when I learnedthe numbers, they were on these
colored charts and they werealmost permanently attached to
the wall in elementary school,and so I'm not sure if my brain
(45:31):
is just applying the colors ofthat chart or if I literally, if
it's a synesthesia thing.
Like I can't think of certainnumbers without also feeling,
sensing a color to go with it.
And I just thought that thatwas normal.
Like how else would I knowunless, like there's so many
(45:52):
things that we think and feeland process that we don't ever
talk about and that they almostcome out accidentally.
And you might be talking aboutit one day and someone goes, huh
, no, that's not what Iexperience, or whatever, and so
you learn about it in theseweird moments and then to find
out later it has a name.
(46:13):
So I'm not, I'm not weird.
Likethis is something that is normal
for our community.
Some of it's very beautiful,like I saw someone on social
media who's autistic, who yougive them your name and they
come up with like this beautiful, like they have this beautiful
almost like rainbow in theirhead of different colors, that
(46:35):
matches each person's name, orlike with a predominant color.
So I think my name has purplein it.
Yay, I love purple! But forthat person, like for another
person, it might be a totallydifferent color scheme, but I
just think that's beautiful, tolike have this parade of colors
that come along with language,like that's beautiful.
(46:57):
I have it with numbers andthey're kind of not exciting
colors and like it's primarycolors, which makes me think
it's just from elementary schooldays.
But anyway, I'd love to hearyour experience of synesthesia.
I don't know if I'm saying itright again.
Like, help me Google.
Synesthesia.
What is it in Romanian?
Google (47:20):
Sinestezie.
Kristen Hovet (47:22):
Nice.
Norwegian! Synestesi.
I like that one.
Okay, well, that's all I havefor you today.
Speaker 3 (47:43):
Thank you so much for being here.
Until next time, bye.
Popular Podcasts
Bookmarked by Reese's Book Club
Welcome to Bookmarked by Reese’s Book Club — the podcast where great stories, bold women, and irresistible conversations collide! Hosted by award-winning journalist Danielle Robay, each week new episodes balance thoughtful literary insight with the fervor of buzzy book trends, pop culture and more. Bookmarked brings together celebrities, tastemakers, influencers and authors from Reese's Book Club and beyond to share stories that transcend the page. Pull up a chair. You’re not just listening — you’re part of the conversation.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
On Purpose with Jay Shetty
I’m Jay Shetty host of On Purpose the worlds #1 Mental Health podcast and I’m so grateful you found us. I started this podcast 5 years ago to invite you into conversations and workshops that are designed to help make you happier, healthier and more healed. I believe that when you (yes you) feel seen, heard and understood you’re able to deal with relationship struggles, work challenges and life’s ups and downs with more ease and grace. I interview experts, celebrities, thought leaders and athletes so that we can grow our mindset, build better habits and uncover a side of them we’ve never seen before. New episodes every Monday and Friday. Your support means the world to me and I don’t take it for granted — click the follow button and leave a review to help us spread the love with On Purpose. I can’t wait for you to listen to your first or 500th episode!