Attentional control of associative learning—A possible role of the central cholinergic system

BRAIN RESEARCH 1202 (2008)43–53

Wolfgang M. Pauli⁎, Randall C. O'Reilly
Department of Psychology, Muenzinger Psychology Building, University of Colorado Boulder, 345 UCB, Boulder, CO 80309-0345, USA

Accepted 9 June 2007
Available online 2 August 2007

Abstract:
How does attention interact with learning? Kruschke [Kruschke, J.K. (2001). Toward a unifiedModel of Attention in Associative Learning. J. Math. Psychol. 45, 812–863.] proposed a model(EXIT) that captures Mackintosh's [Mackintosh, N.J. (1975). A theory of attention: Variationsin the associability of stimuli with reinforcement. Psychological Review, 82(4), 276–298.]framework for attentional modulation of associative learning. We developed acomputational model that showed analogous interactions between selective attentionand associative learning, but is significantly simplified and, in contrast to EXIT, is motivatedby neurophysiological findings. Competition among input representations in the internalrepresentation layer, which increases the contrast between stimuli, is critical for simulatingthese interactions in human behavior. Furthermore, this competition is modulated in a waythat might be consistent with the phasic activation of the central cholinergic system, whichmodulates activity in sensory cortices. Specifically, phasic increases in acetylcholine cancause increased excitability of both pyramidal excitatory neurons in cortical layers II/III andcortical GABAergic inhibitory interneurons targeting the same pyramidal neurons. Theseeffects result in increased attentional contrast in our model. This model thus represents aninitial attempt to link human attentional learning data with underlying neural substrates.