Purkinje cell activity during classical conditioning with different conditional stimuli explains central tenet of Rescorla–Wagner model [corrected]

Proc Natl Acad Sci U S A. 2015 Nov 10;112(45):14060-5. doi: 10.1073/pnas.1516986112. Epub 2015 Oct 26.

Abstract

A central tenet of Rescorla and Wagner's model of associative learning is that the reinforcement value of a paired trial diminishes as the associative strength between the presented stimuli increases. Despite its fundamental importance to behavioral sciences, the neural mechanisms underlying the model have not been fully explored. Here, we present findings that, taken together, can explain why a stronger association leads to a reduced reinforcement value, within the context of eyeblink conditioning. Specifically, we show that learned pause responses in Purkinje cells, which trigger adaptively timed conditioned eyeblinks, suppress the unconditional stimulus (US) signal in a graded manner. Furthermore, by examining how Purkinje cells respond to two distinct conditional stimuli and to a compound stimulus, we provide evidence that could potentially help explain the somewhat counterintuitive overexpectation phenomenon, which was derived from the Rescorla-Wagner model.

Keywords: Rescorla–Wagner model; climbing fibers; eyeblink conditioning; inferior olive; nucleo-olivary pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Association Learning / physiology*
  • Blinking / physiology
  • Conditioning, Classical / physiology*
  • Extinction, Psychological
  • Humans
  • Models, Psychological*
  • Purkinje Cells / physiology*
  • Reinforcement, Psychology*