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 GABA

A)

• 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 GABA

A)

• 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) Model

J 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.