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PRODID:-//Memento EPFL//
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SUMMARY:Spike-Timing Theory of Working Memory
DTSTART:20101122T141500
DTSTAMP:20260603T020500Z
UID:e69239ac5ccabab1d5aeab9735a75581451def20c436c2f51a3b581c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Eugene IZHIKEVICH\, Chairman and CEO of the Brain Corporation\
 nWorking memory (WM) is the part of the brain's memory system that provide
 s temporary storage and manipulation of information necessary for cognitio
 n. Although WM has limited capacity at any given time\, it has vast memory
  content in the sense that it acts on the brain's nearly infinite repertoi
 re of lifetime long-term memories. Using simulations\, we show that large 
 memory content and WM functionality emerge spontaneously if we take the sp
 ike-timing nature of neuronal processing into account. Here\, memories are
  represented by extensively overlapping groups of neurons that exhibit ste
 reotypical time-locked spatiotemporal spike-timing patterns\, called polyc
 hronous patterns\; and synapses forming such polychronous neuronal groups 
 (PNGs) are subject to associative synaptic plasticity in the form of both 
 long-term and short-term spike-timing dependent plasticity. While long-ter
 m potentiation is essential in PNG formation\, we show how short-term plas
 ticity can temporarily strengthen the synapses of selected PNGs and lead t
 o an increase in the spontaneous reactivation rate of these PNGs. This inc
 reased reactivation rate\, consistent with in vivo recordings during WM ta
 sks\, results in high interspike interval variability and irregular\, yet 
 systematically changing\, elevated firing rate profiles within the neurons
  of the selected PNGs. Additionally\, our theory explains the relationship
  between such slowly changing firing rates and precisely timed spikes\, an
 d it reveals a novel relationship between WM and the perception of time on
  the order of seconds.
LOCATION:CO 123
STATUS:CONFIRMED
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