Learning Reward Uncertainty in the Basal Ganglia
Fig 4
Effects of dopamine (DA) on action selection between safe and risky options.
Circles denote different neural populations: black circle corresponds to the neural population in cortex selective for the current state, green circle corresponds to dopaminergic neurons, and blue and orange circles correspond to the striatal neurons selective for two different actions. The circles receiving inputs via connections Gi and Ni correspond to D1 and D2 neurons. Arrows and lines ending with circles denote connections with excitatory and inhibitory effect respectively. The top panel illustrates a situation of high tonic level of DA, where the D2 neurons are inhibited (indicated by bleak color), while the bottom panel corresponds to low DA, where the D1 neurons are inhibited.