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SUMMARY:BMI Progress Reports 2020 // Prof. Gerstner's Lab - Chiara Gastald
 i: How can shared concept cells encode associations?
DTSTART:20201104T121500
DTEND:20201104T130000
DTSTAMP:20260407T030043Z
UID:bc8c77f8e679349f137516698abf7bde48daa2dbb9c3fc058f5af9ce
CATEGORIES:Conferences - Seminars
DESCRIPTION:Chiara Gastaldi\, Laboratory of Computational Neuroscience\, B
 MI\nExperimental evidence suggests that memories of concepts such as 'the 
 actress Jennifer Aniston' or 'the Sidney opera house' are stored in the Me
 dium Temporal Lobe [1\,2]. Each concept is represented by a sparse cell as
 sembly ('memory engram') so that only a small fraction of neurons respond 
 to a concept such as 'the Sidney Opera House'.   Associations between di
 fferent concepts  ('Jennifer Aniston in the Sidney Opera House' ) are re
 lated to shared concept cells: assemblies representing two arbitrary conce
 pts share less than 1% of neurons\, whereas assemblies representing previo
 usly associated concepts (e.g.\, you have often seen Jennifer Aniston in t
 he Sidney Opera house) share up to 4-5% of neurons in the Medial Temporal 
 Lobe [3].  Associations between concepts can also be probed by free recal
 l of words. Theoretical studies suggest that shared neurons between memory
  engrams are fundamental for the generation of sequences of words during f
 ree recall [4].\nI will present a modeling study of associative memory usi
 ng attractor neural networks.  I demonstrate that correlations between me
 mory engrams induced by shared concept cells modify the memory recall proc
 ess and provide a robust way to encode associations between pairs of conce
 pts. Moreover\, I will show that the free recall of a chain of concepts is
  possible in very sparse attractor networks only if engrams are correlated
 .  Our model provides a possible explanation of how association are store
 d in highly sparse networks (such as the Medial Temporal Lobe) and how cor
 related memories are recalled in the form of association chains. \n[1] Q
 uiroga\, R. Quian\, et al. "Invariant visual representation by single neur
 ons in the human brain." Nature 435.7045 (2005): 1102-1107.\n[2] Ison\,
  Matias J.\, and Rodrigo Quian Quiroga. "Selectivity and invariance for vi
 sual object perception." Front Biosci 13 (2008): 4889-4903.\n[3]  De Fa
 lco\, Emanuela\, et al. "Long-term coding of personal and universal associ
 ations underlying the memory web in the human brain." Nature communicatio
 ns 7.1 (2016): 1-11.\n[4] Naim\, Michelangelo\, et al. "Fundamental law 
 of memory recall." Physical Review Letters 124.1 (2020): 018101.\n 
LOCATION:Online https://epfl.zoom.us/meeting/register/tJIvceqhqjMpGtGHWZQ7
 gmu96_V8MXMdgpnX
STATUS:CONFIRMED
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