Modeling some effects of
frontal lobe damage: Novelty and perseveration.
Neural networks are presented which simulate some behavioral
effects of frontal lobe damage. On some cognitive tasks, frontal
lesions cause perseveration of formerly rewarding choices of action.
On other tasks, frontal lesions cause approach to objects just because
they are novel. Both effects can be explained by weakening of signals
between sensory and reinforcement loci. The networks that reproduce these
data incorporate neural design principles developed for other purposes
by Grossberg and his co-workers. These design principles include
adaptive resonance between two layers of sensory processing; attentional
gating of synapses between layers; and competition among gated dipoles
containing on-units and off-units.