Figure 1.

(A) Neural architecture consisting of an input area, a Decremental area, a cholinergic neuromodulatory system (MS/VDB), a Modulated input area, and an action selection area. Every neural area had two neurons responding to different input cues. Between different neural areas, these neurons were connected through “one-to-one” synaptic projections. The dashed lines represent inhibitory projections. An action was selected if the activity of a neuron in the Action selection area was above a certain threshold (0.5), otherwise a random choice was made. (B) Description of a trial. During each trial, the model was presented with two cues simultaneously for 10 time-steps (observation period). At the tenth time-step, the model made a selection. Once a cue was chosen, the model was presented with the selected cue for an additional 10 time-steps (action period).