Modeling the role of the frontal lobes in sequential performance. II. Classification of sequences.
    An avalanche model of motor sequence encoding, presented in a previous article (Bapi & Levine, 1994), is extended.  The model is designed to reproduce data showing that monkeys with frontal lobe damage can learn an invariant sequence of movements if it is rewarded, but cannot learn to perform any one of several variations on a sequence if all are rewarded.  In this article, we add to our previous network for sequence encoding an extra module that classifies these temporal sequences and groups them together based on reward.  This module is based on a simplified version of ARTMAP (Carpenter, Grossberg, & Reynolds, 1992).  The network's behavior reproduces data of Brody and Pribram (1978) showing that frontally damaged monkeys can perform a flexible sequence task if they limit their performance to some of the possible variations on the sequence.  Analogies are drawn between the classifier layer and the frontal lobes, and between the avalanche module and part of the basal ganglia.