Thread by @eglerean

Soon starting Em. Prof. Riita Hari (Aalto University) @aivoAALTO :
"How to react fast with a slow brain".

Live stream at this link: connect.funet.fi/neuroscience/
Live tweeting under #brainandmind hashtag.

I once again have high expectations from this talk!

Introduction about Riitta Hari by @hovatta with the long list of achievements that I will not mention here for lack of space. :) #brainandmind

RH: "is the brain fast or slow? it seems to be a bit of both" #brainandmind

RH: "quoting @RodolfoLlinas "We know about the brain almost everything, except how it works""

RH: "Neuroscience suffers tunnel vision unless continuous with ethology, ecology, and evolution" Ted Bullocck, Science 1984 #brainandmind

RH: "Triumph of connectome" lots of excitement to map connections of different brain regions and see which parts of the brain are active #brainandmind

RH "static pictures are not helpful though..." #brainandmind
(note, that's why I love GIFs!)

RH "Time scales of the brain" the top influences the bottom and viceversa although the time scales of the brain are at a limited range ncbi.nlm.nih.gov/pubmed/20392277

RH is now talking about multiple time scales from sound delays for localization ( < ms) to slow mood changes (>s)

Reaction time depends on alternatives Merkel 1885. #brainandmind

RH: but what about football?? The goalkeeper has to anticipate, there is not enough time to react

RH is now talking about time to cortex pnas.org/content/100/5/…

RH "multisensory asynchrony is tolerated up to 200-300 ms" or "sluggish perceptions" e.g. by mismatching binaural left-right clicks.

RH: "So is the brain slow or fast?" fastest myelinated fibers are at 100m/s (360km/h), slow unmyelinated 0.5 m/s (1.8 km/h) #brainandmind

(personal note, it is very complicated to think at the temporal scales of the brain, there was an interesting figure from this recent review by @spornslab and @DaniSBassett that remakes and extend the original picture on types of neuroimaging methods ncbi.nlm.nih.gov/pubmed/28230844)

RH is talking about tradeoffs btw fiber speed and density now. There are so many references that I can't keep up #brainandmind

RH: "fibers can be dense or fast, not at the same time" #brainandmind

RH: "brain rhythms and frequencies in different animals" #brainandmind
ncbi.nlm.nih.gov/pmc/articles/P…

Commenting the same article by Buzsaki on how the rhythmic activity seem to be independent to brain size (weight)

RH: "we are bundles of habits" talking about prior knowledge. Again illusions illusions!! #brainandmind

RH: "DO NOT READ THIS TEXT" (I can feel Gödel smiling in his grave) #brainandmind

RH: "the brain is not only reactive: stimuli and tasks change brain's metabolism very little" which reminds me of this nice paper by Mennes ncbi.nlm.nih.gov/pubmed/22298730 and this by @TheColeLab ncbi.nlm.nih.gov/pmc/articles/P… on how similar the networks are at task and rest

RH talking about compression like video compression where we store only the changes of pixels, rather than all the pixels. "predictive coding" #brainandmind

RH "predictions improve. Surprises decrease" #brainandmind

RH citing cell.com/trends/cogniti…

RH "we react to deviations from expectations" (similar slide from last year's #brainTC)

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#brainandmind

RH: "reacting fast: some tricks -> inhibiting improper movements" Cerebellum and basal ganglia (as well as the whole brain) play important role in inhibition #brainandmind

And now time sequences! #brainandmind

Classic figure from Thorpe 2001 Science

RH "but is it really a 1 way system?" Well no! #brainandmind

Another classic picture from Felleman von Essen 1991 #brainandmind

There is lots of feedback since just looking at the signals seems not to give a simple sequential pattern #brainandmind

Same input different percept. Work from pnas.org/content/105/51… #brainandmind

RH "early visual cortices are already spotting these very tiny differences" #brainandmind

RH citing Dehaene Neuron 2011 "if subliminal processing, only feed forward, otherwise feedback is needed" ncbi.nlm.nih.gov/pubmed/21521609 #brainandmind

AMPA (feed forward, fast) NMDA (feedback, slow) #brainandmind

why is conversation so easy "humans are designed for dialogues, not monologues" ncbi.nlm.nih.gov/pubmed/14697397 #brainandmind

RH on turn taking (preparation for utterances) is universal and fast sciencedirect.com/science/articl… #brainandmind

RH: "social interaction is complicated" ... but goes surprisingly effortlessly. "we thought that communication is ping pong playing sending and receiving, but no!" #brainandmind

RH "communication is more like three legged walk" the two runners with one leg tied with each other. #brainandmind

RH "and the body of course" #brainandmind
(selfless plug to our study on body maps: pnas.org/content/111/2/… )

RH:"so how can we catch a scene so fast?" Rich experience is an illusion because humans are so strongly foveal animals."people are looking at the world at a fixation at a time and then followed by saccade suppression: how can we get such a rich feeling of the env?" #brainandmind

RH "many of us have ignored the peripheral retina" #brainandmind
cvcl.mit.edu/Papers/OlivaTo…

RH "summary statistics gives enough info for zombi type behaviour" #brainandmind

RH "retina itself has two speeds, what comes from perif retina reaches the brain earlier" cell.com/cell/pdf/S0092… #brainandmind

RH: "so what can we learn by studying the brain with non invasive methods?" could a neuroscientist understand a microprocessor? journals.plos.org/ploscompbiol/a… by @KordingLab @stochastician

RH "and can a biologist fix a radio?" cell.com/cancer-cell/ab… (another classic!)

RH making the audience smiling with the classic paper from link above.

RH: "people should go back to the original literature form 100s years ago to understand the radio"

RH concluding "how to react fast with a slow brain?" "if you want a better answer, ask a better question" #brainandmind

Talk is over

(it was so difficult to keep up with all the citations, I have missed at least 30%... for sure @aivoAALTO is too fast)

Questions on how to merge and combine all the multiple levels. RH "there are many opinions, some physicists think that everything can be explained by lower levels" (personal note: and the search for universality and free scale loved by (some) physicists) #brainandmind

Q: what do we miss as biologists? do we miss something we don't understand? (e.g. collaborators from other fields). RH: "we are missing behaviour very badly". (my note: I COULDN'T AGREE MORE SORRY FOR SCREAMING)

RH citing this paper ncbi.nlm.nih.gov/pmc/articles/P… on behaviour in mice and reducing it into units

RH stating also the importance of studying the environment as well as circadian rhythms and the physical laws (as in how we move in space) #brainandmind

Q: why do we have two hemisphere? Kai Kaila: we are bilateral animals and so the crossing (left right crossing of major tracts to get integration)

KK: "the quote of Llinas is misleading, does it makes sense to ask if we understand how the brain works?" RH: the idea of RL is to provoke of course, we would need some framework not just more data (personal note: yes! #bigdata is not going to save you dear scientists)

Q: vision and aural system are so different when it comes to temporal scales (I cannot write down the question because I did not understand it, sorry, no offence :))

That’s it! Great success!!! #brainandmind

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