transcript of episode 26: FINDING THE CLITORIS, 11th March 2022
welcome to the error bar: bursting brain science news bubbles
in this episode: how to find the clitoris, how covid shrinks some very important parts of the brain & the canadian brain disease that isn't. still.
here is the brain news on the 11th March 2022:
[🎶 BIG BEN BONGS 🎶]
THE CLITORIS HAS BEEN FOUND
in a rare case of an open-access scientific paper about sex being missed by all the news media, the female clitoris has, at last, been found.
the general anatomy of the brain is not a mystery & has been known about for centuries. in the 1920s to 1950s, the specific anatomy of the brain areas that respond to touch on the body were systematically mapped. there's an area for touch on the hand - i study that one - another for the foot, another for the face.
but the genitals have not been mapped precisely. well, i say genitals, but of course, following international women's day, i mean the clitoris. the penis was properly mapped - with non-arousing stroking of the penile shaft inside the brain scanner - as long ago as 2005, but the first studies of the clitoris came six years later. see what i did there?
the new study asked 25 women to go into a brain scanner with a vibrating dome & 25 minutes to themselves. with a punishing 32 repetitions of 10 seconds of the dome vibrating under their mons pubis, plus another 320 seconds vibrating their hand, science was finally able to find the clitoris in the brain.
the clitoris is, aptly, underneath a fold in the uppermost part of the brain's main & important sensory area - the postcentral gyrus. no great surprises really, apart from that it's not in the place where the penis was located, way back in the 20th century.
[🎶 INTERLUDE 🎶]
has the clitoris been found?
this study & its results are clear & simple - in those women for whom the experiment worked, the area of the brain activated by the clitoral stimulation, as well as the area for the hand stimulation, were neat & precisely-located on the brain. so, job done, right?
well, no. error bar nerds wouldn't be getting their money's worth if i didn't raise a few problems, so here they are.
first, 25 women were recruited for the study - & presumably scanned - but no information other than 'it didn't work' was provided for 5 of them. what happened to those 5? did they not find their own clitoris? did the brain not activate? was it a statistical problem? nothing is given, & that's a problem.
second, a further conclusion of the study was that the self-reported frequency of sexual activity was related to the thickness of the clitoral area on the left side of the brain, but not the right side. this relationship was found only after the analysis included several other factors, for example age, years of sexual activity & whole-brain thickness. it would be good if the authors had reported the analysis without these additional factors, just to be sure.
it also seems that in this extra analysis two additional women's data were excluded. but again - & troublingly - no details are given about these removals. given that this weak, post-hoc relationship was found on only one side of the brain & only after accounting for some other things, i think we can ignore the relationship between brain thickness & sexual activity.
this clear and simple brain imaging study has indeed found the clitoris, but why shroud the results in mystery by excluding 5 & then 7 of the participants in different analyses. some deeper probing is required.
the science was by Knop et al. 2022: Journal of Neuroscience;
[🎶 BIG BEN BONGS 🎶]
COVID SHRINKS BRAIN
in a study echoed across lots of news media this week, the Guardian reports that brain scientists from Oxford found that even mild cases of COVID shrinks the brain & damages its tissue.
[before i continue, an editorial note: the error bar has not cover COVID stories so far, to avoid the inevitable trolling, but this one was too prominent to ignore.]
the study relied on the UK's BioBank - a long term research study that has scanned the brains & tested the minds & bodies of thousands of people. in this specific study, 785 typically-healthy older adults' brains were scanned twice. the first scan was done before COVID arrived, the second was done an average of 38 months later, which was, coincidentally, four & a half months after infection with COVID in about half of the people.
the scans revealed that the overall brain size decreased more in those who had COVID & that some brain areas linked to smell & taste showed larger & specific decreases in brain size.
perhaps most significant is that these decreases in brain volume were observable even though the volunteers had mostly had mild symptoms, & the differences remained when 15 more severe cases were excluded.
[🎶 INTERLUDE 🎶]
does covid shrink the brain?
yes, it seems so.
but don't believe all the headlines - it's not as bad as it might sound.
first, the study covered a very wide age-range of participants - from 51 to 80 years - but there was much less 'brain shrinkage' in the youngest participants. because of the way the data are presented, it looks like there is a continuous & larger decrease in brain size as age increases from 56 to 76, but this depends partly on the authors using a 10-year 'sliding window' to average the data. that means the 56-year-old data includes 51 to 61 year-olds. so it might be that only those over 65 show brain shrinkage - it's not quite clear.
second, it's not the whole brain that is shrinking, but rather several important parts of the brain related, arguably, to smell & taste. & some brain areas or signals seemed to *increase* in size too. so it's not a simple story, but overall there seem to be clear differences between the groups.
third, although every bit of brain is important & COVID-related brain loss seems to accelerate with age, these are still relatively small changes, occurring in people with only mild illness. the changes may largely reflect what happens when you lose your sense of smell & taste.
this important study shows that, on average, the oldest participants' brains were more affected by covid than the youngest. some brain areas & signals got bigger, some smaller. overall, there was a small decrease in brain size after covid.
and the brain in brief...
[🎶 BIG BEN BONGS 🎶]
NEW CANADA BRAIN DISEASE NOT NEW
regular listeners will recall that the error bar was amongst the first in the UK to break the news of a worrying new neurological disease in Canada. the cases in Spring 2021 were all clustered around New Brunswick, as we reported in Episode 9.
in episode 21, the error bar boldly updated its listening nerds with news of the controversy that the cluster of disease may - in fact - just be a cluster of mis-diagnoses made by a single neurologist.
in yet ANOTHER UK EXCLUSIVE - i mean, the Washington Post got there first - the error bar can confirm that, yes, this whole story was an error. rather than 48 cases & 10 deaths being due to a new neurological disease, at least 41 of them were other diseases. these include:
"Alzheimerâ€™s disease, Lewy body dementia, Parkinsonâ€™s disease, post-concussion syndrome, cancer and paranoid schizophrenia."
perhaps these cases - all real, serious, neurological diseases - were complicated by COVID, lockdown & social isolation.
stay tuned for updates
it's closing time at the error bar, but do drop in next time for more brain news, fact-checking & neuro-opinions. take care.
the error bar was devised & produced by Dr Nick Holmes from University of Birmingham's School of Sport, Exercise and Rehabilitation Sciences. the music by Dee Yan-Kee is available from the free music archive. find us at the error bar dot com, on twitter at bar error, or email talk at the error bar dot com.ε