A Model of the Effects of Scopolamine on Human Memory Performance

  • Bradley P. Wyble
  • Michael E. Hasselmo


The effects of scopolamine on human memory function are simulated in a network model of the hippocampal formation, incorporating simplified simulations of neurons and synaptic connections. In this model, the dentate gyrus, CAI and CA3 maintain sparse representations of list items and their associated context allowing simulation of recognition and free recall. Blockade of cholinergic effects within this computational representation models the effects of scopolamine. This blockade of cholinergie effects impairs the encoding of new input patterns (as measured by delayed free recall), but not retrieval of previously learned patterns. Additionally, this cholinergic blockade has no significant effect on recognition tasks. The model also accomodates qualitative aspects of both the List Strength Effect and the List Length Effect.


Free Recall Entorhinal Cortex Sparse Representation List Length Attractor Dynamic 
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Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Bradley P. Wyble
    • 1
  • Michael E. Hasselmo
    • 1
  1. 1.Department of PsychologyHarvard UniversityCambridgeUSA

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