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SUMMARY:Predictions and errors are distinctly represented across V1 layers
  - Ivan Tomic
DTSTART:20240904T130000Z
DTEND:20240904T140000Z
UID:TALK220693@talks.cam.ac.uk
CONTACT:Adam Triabhall
DESCRIPTION:This week we will discuss and debate a very recent paper by Th
 omas and colleagues\, published in Current Biology (2024).\n\nAbstract: 
 “Popular accounts of mind and brain propose that the brain continuously 
 forms predictions about future sensory inputs and combines predictions wit
 h inputs to determine what we perceive. Under “predictive processing” 
 schemes\, such integration is supported by the hierarchical organization o
 f the cortex\, whereby feedback connections communicate predictions from h
 igher-level deep layers to agranular (superficial and deep) lower-level la
 yers. Predictions are compared with input to compute the “prediction err
 or\,” which is transmitted up the hierarchy from superficial layers of l
 ower cortical regions to the middle layers of higher areas\, to update hig
 her-level predictions until errors are reconciled. In the primary visual c
 ortex (V1)\, predictions have thereby been proposed to influence represent
 ations in deep layers while error signals may be computed in superficial l
 ayers. Despite the framework’s popularity\, there is little evidence for
  these functional distinctions because\, to our knowledge\, unexpected sen
 sory events have not previously been presented in human laminar paradigms 
 to contrast against expected events. To this end\, this 7T fMRI study cont
 rasted V1 responses to expected (75% likely) and unexpected (25%) Gabor or
 ientations. Multivariate decoding analyses revealed an interaction between
  expectation and layer\, such that expected events could be decoded with c
 omparable accuracy across layers\, while unexpected events could only be d
 ecoded in superficial laminae. Although these results are in line with the
 se accounts that have been popular for decades\, such distinctions have no
 t previously been demonstrated in humans. We discuss how both prediction a
 nd error processes may operate together to shape our unitary perceptual ex
 periences” (Thomas et al.\, 2024).\n\nReference: Thomas\, E. R.\, Haarsm
 a\, J.\, Nicholson\, J.\, Yon\, D.\, Kok\, P.\, & Press\, C. (2024). Predi
 ctions and errors are distinctly represented across V1 layers. Current Bio
 logy\, 34(10)\, 2265-2271.e4. https://doi.org/10.1016/j.cub.2024.04.036
LOCATION:https://cam-ac-uk.zoom.us/j/92612577704?pwd=MUtqMjVQdXNmUTVIYjRkM
 G1NUW9GZz09
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