transcript of episode 32: EMOTIONAL FISH FOOD, 21st October 2022

[🎶 INTRO: "Spring Swing" by Dee Yan-Kee 🎶]

welcome to the error bar: broadcasting longer than 14 UK prime ministers

in this episode: how the largest part of the brain gets emotional, why older adults don't get emotion, how goldfish can swim 70cm for food & free energy forever!

here is the brain news on the 21st October 2022:

[🎶 BIG BEN BONGS 🎶]

THE BRAIN'S LITTLE BRAIN IS EMOTIONAL

in recent episodes, the error bar has been a grumpy old academic, slumped in a dirty armchair, biting statistical chunks out of the brain science papers that appear in the grubby news media.

but in this episode, an impressive amount of brain scanning work has been spun into a clear, simple story with a singular, powerful result: the cerebellum - an important part of the brain involved in everything - is involved in viewing & memory of emotional pictures.

eleven scientists from Basel in Switzerland put one thousand four hundred & eighteen people aged 18 to 35 in a brain scanner & asked them to view, rate - & later to remember - a series of positive, neutral or negative images. this enormous pile of brain & behavioural data were analysed to answer two simple questions: do people remember emotional material better than neutral material? & is the cerebellum involved?

the answers were yes & yes. these 1418 brain scans showed that a part of the cerebellum which looks like a worm - the vermis - was involved in a network of brain areas that responded to the emotional stimuli.

[🎶 INTERLUDE 🎶]

does the brain's own little brain do emotion?

yes.

for years there have been arguments between those who think the cerebellum is only involved in controlling bodily movements & those who think it does more than that. the cerebellum definitely does do movement, but as it contains about two-thirds of all the brain cells in the human nervous system, we should really not be surprised to find out that the cerebellum does a lot more.

an old colleague of mine is obsessed with the cerebellum & with computational theories of how it works & what it does. one of my favourite ways that he explained it to me was that the rest of the brain's job is to filter-out & select the information that is relevant for whatever job you are doing now. it sends the filtered information to the cerebellum which gets the job done. then it sends feedback to the rest of the brain about how it went & what to do next.

to use a political analogy from the UK, the rest of the brain is the 650 elected members of the houses of parliament who have ideas, set policy & bear ultimate responsibility for the decisions & for the narrative. the cerebellum is the 512 thousand civil servants who implement the policy, monitor its effects on the world & tell the rest of the brain how well it went down.

& if you disabuse yourself of the dogma that the cerebellum is only for movement, you may see that anything that we are doing - thinking, feeling, remembering, emoting - can be understood in the same way.

& this latest paper hammers another cold, hard, statistically-unbendable nail into the coffin of the cerebellum-only-does-movement world view.

conclusion

[ ...clapping... ]

sources

the science was by Fastenrath et al. 2022: Proceedings of the National Academy of Sciences of the United States of America; reported in The Independent by Vishwam Sankaran on 10/Oct/22


[🎶 BIG BEN BONGS 🎶]

EMOTIONAL HEARING DECLINES WITH AGE

the Daily Mail explains why 'grandparents don't understand jokes' according to a study which did not involve grandparents or jokes.

instead, the researchers gave a group of people of about 22 years old & another group of people about 68 years old a series of nonsense sentences. the sentences had been spoken by an actor & were supposed to sound emotional - happy, sad, angry, disgusted, fearful, pleasantly surprised or neutral. after hearing each nonsense sentence, the volunteers indicated which of the seven possible emotions were being expressed.

there was also some brain recording & brain stimulation going on, but the Daily Mail & the authors focused mostly on the finding that older adults were worse at discriminating which emotion was being acted out in the nonsense speech sounds. some emotions were also harder to discriminate than others.

[🎶 INTERLUDE 🎶]

are older people worse at discriminating emotion?

maybe.

the study is relatively straight-forward, the authors have collected lots of data & the conclusion that older adults are worse at something than younger adults is perhaps not surprising. but the error bar wants to say this:

first, older adults were just worse in general than younger adults. we don't know if this is specific to the particular groups of adults they were recruiting, for example young university students versus a community sample of older adults.

second, we also don't know that this is specific to emotional discrimination, since no other tasks were included in the study - perhaps the older adults just had worse hearing? hearing was not tested, but everyone at least reported having no problems.

third, while the newspaper & the authors both make specific conclusions about differences between the groups in individual emotions, for example about happy versus sad or angry, the data does not support this - in the jargon there was 'no statistical interaction between age & emotion'. further, any differences between emotions could also be due to the single actor who voiced the speech being better at conveying some emotions than others.

fourth, the brain imaging data suggest that the younger participants were doing something quite differently to the older adults. immediately before the speech stimuli were presented, the young adults' data look very clear, but the older adults look less clear. & this suggests differences in how the young adults were preparing to listen to the sounds, during the so-called fixation period before the speech was presented.

fifth, the brain imaging data - using electroencephalography, or EEG - are rather vague with respect to what, exactly, was being measured. EEG is known for its ability to distinguish what's going on at different times in the brain. the timing information is really important. the researchers analysed two time periods of information, from 180 to 280 milliseconds & from 280 to 400 milliseconds after the speech began. so all these data are from the first half a second of the speech that was being listened to. but, according to a previous paper - & not reported by the current one - the sentences were an average of two to three seconds long. so the brain imaging data, therefore, relate only to the onset of the sounds & likely not their emotional content.

sixth, both of the brain stimulation experiments did not have any effect. the error bar celebrates the reporting of negative brain stimulation results.

conclusion

this paper provides no evidence that older adults are worse than younger adults at emotional speech processing; nor that the brain areas or signals studied play any role in emotional speech processing. no jokes were told.

sources

the science was by Maltezou-Papastylianou et al. 2022: Public Library of Science ONE; reported in The Daily Mail by @xanthaleatham on 19/Oct/22


[🎶 BIG BEN BONGS 🎶]

GOLDFISH LEARN TO SWIM 70CM FOR FOOD

goldfish learn to swim 70cm for food.

[...]

[...]

that's it. that's the story.

[🎶 INTERLUDE 🎶]

do goldfish learn to swim 70cm for food?

yes.

[...]

[...]

conclusion

find out more next episode

sources

the science was by Sibeaux et al. 2022: Proceedings of the Royal Society of London, B: Biological Sciences; reported in The Daily Mail by Victoria Allen on 12/Oct/22, & The Times by @rhysblakely on 12/Oct/22


and the brain in brief...

[🎶 BIG BEN BONGS 🎶]

'KING PONG

producing an unpopular brain science news podcast takes a lot of work & there has to be some editorial selection of which news stories to cover. in the last few weeks, lots of media has got excited about the neurons in a dish that were trained to play the game 'pong'. so the error bar investigated.

i read the abstract of the paper as far as the words 'free energy principle' & then vomited.

for listeners interested in the story, i recommend some of the discussion on pubpeer.com & twitter.

conclusion

pong

sources

the science was by Kagan et al. 2022: Neuron; reported in The Guardian by @ToryShepherd on 12/Oct/22


[🎶 OUTRO: "Cosmopolitan - Margarita - Bellini"by Dee Yan-Kee 🎶]

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