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Summary Working memory storage and decision-making computations: shared microcircuit mechanisms in a local cortical (e.g. prefrontal, parietal, premotor) area. Coherent fast oscillation may be a common signature of the engagement of strongly recurrent network dynamics. Detection of threshold-crossing: a mode of communication between brain areas, for gating information flow or selecting a motor action. Reward-gated Hebbian plasticity in a decision network: a cellular basis of flexible sensori-motor mapping.
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Wang TINS 2001Wang et al PNAS 2004 Wang Neuron 2002
400ms
Lorente de Nó’s reverberatory circuit
Levitt et al 1993Kritzer and Goldman-Rakic 1995Pucak et al 1996
Summary
• Working memory storage and decision-making computations: shared microcircuit mechanisms in a local cortical (e.g. prefrontal, parietal, premotor) area. Coherent fast oscillation may be a common signature of the engagement of strongly recurrent network dynamics.
• Detection of threshold-crossing: a mode of communication between brain areas, for gating information flow or selecting a motor action.
• Reward-gated Hebbian plasticity in a decision network: a cellular basis of flexible sensori-motor mapping.
Probabilistic decision-making in a visual motion two-alternative forced choice task
W Newsome
Roitman and Shadlen 2002
• 2-population excitatory and inhibitory neurons (integrate-and-fire or conductance-based Hodgkin-Huxley neurons)
• Biologically realistic synaptic kinetics (AMPA, NMDA and GABAA)
• Structured network connectivity
Brunel & Wang JCNS2001
Wang Neuron 2002
Dynamical stability and NMDA/AMPA
ratio at the recurrent synapses
C D RWang J Neurosci 1999
Compte, Brunel, Goldman-Rakic,Wang Cereb Cortex 2000
Brunel and Wang J Neurophysiol 2003
• 2-population excitatory and inhibitory neurons (integrate-and-fire or conductance-based neurons)
• Biologically realistic synaptic kinetics (AMPA, NMDA and GABAA)
• Structured network connectivity
Brunel & Wang JCNS2001
Wang Neuron 2002
MT output
Reaction Time Simulations
Model
Data
Data by J Roitman, J Ditterich and M Shadlen
Reaction time decreases with increasing coherence Weber's Law
Scale-invariance of the reaction time distributions
c’=51.2%c’=0%
Integrate-and-Decide (diffusion) ModelJ Schall (Nature Rev Neurosci 2001)
But how is threshold-crossing readout by downstream neurons?
Flexible sensori-motor association
(with Stefano Fusi)
Flexible Sensori-motor Association
(Asaad, Rainer and Miller Neuron 1998, Wise and Murray TINS 2000)
Locus and biophysical basis of reward-gated synaptic plasticity?
Summary
• Working memory storage and decision-making computations: shared microcircuit mechanisms in a local cortical (e.g. prefrontal, parietal, premotor) area. Coherent fast oscillation may be a common signature of the engagement of strongly recurrent network dynamics.
• Detection of threshold-crossing: a mode of communication between brain areas, for gating information flow or selecting a motor action.
• Reward-gated Hebbian plasticity in a decision network: a cellular basis of flexible sensori-motor mapping.
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