Wang TINS 2001 Wang Neuron 2002 n integrated microcircuit model of working memory and decision makin
Apr 01, 2015
Wang TINS 2001 Wang Neuron 2002
An integrated microcircuit model of working memory and decision making
Lorente de Nó’s reverberatory circuit
Roitman and Shadlen 2002
Roitman and Shadlen 2002
Reaction Time Task
• 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
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
Integrate-and-Decide (diffusion) Model
R Ratcliff (Psychol Rev 1978)J Schall (Nature Rev Neurosci 2001)Mazurek et al (Cereb Cortex 2003)
Kong-Fatt Wong
c’=6.4%
c’=51.2% c’=100%
D Munoz and R Wurtz
Fixation
Target
A bursty neuron in superior colliculus
But how is threshold-crossing readout by downstream neurons?
Bistability: hard threshold detection
Chung-Chuan Lo
Feedback Inhibition: Bursting
A Large-scale Network Model of Decision-Making
Cortex
Caudate
SNr
SC
LIP Network
SC Network
Threshold can be effectively modulated by the cortico-striatal synaptic pathway
Adjusting the threshold to optimize rewards: Speed-accuracy tradeoff
Optimal threshold should be adjustable according tothe distribution of coherence levels in the environment
End