Elsevier

Brain Research

Volume 167, Issue 1, 4 May 1979, Pages 129-138
Brain Research

Separation of associative from non-associative short latency changes in medial geniculate and inferior colliculus during differential conditioning and reversal in rats

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Abstract

Results obtained in a recent experiment in this laboratory drew attention to the possible contribution of subtle non-associative processes to changes in the early latency unit responses obtained in MGB and IC of the rat during the learning of a differential appetitive conditioning task. An important possible source of such non-associative effects was shown to arise from differences in the interval between a previous food pellet presentation and the following CS+ or CS−. To determine whether previously reported changes in MGB and IC were due to associative processes or to non-associative ones, the present experiments were carried out using a counterbalanced stimulus presentation schedule which placed the CS+ and CS− at the same average time following a previous food pellet. Criteria adopted for characterizing a change as associative required that the response to the CS+ be enhanced relative to that to the CS− throughout repeated reversal sessions.

The results obtained support previous findings of early latency associative changes in MGB, and are consistent with the idea that such changes are most likely to occur in the medial division of this nucleus. The findings in the IC thus far do not support the notion that this nucleus participates in this process. However, in view of the complex structure of the IC and the fact that not all of its subdivisions were sampled, these negative findings must be viewed with caution. The results also support the view that the anatomical distribution of neurons participating in the elaboration of associative changes may be more restricted than that of neurons participating in non-associative ones.

References (42)

  • SteriadeM. et al.

    Some synaptic inputs and ascending projections of lateralis posterior thalamic neurons

    Brain Research

    (1977)
  • SteriadeM. et al.

    Reticular influences on lateralis posterior thalamic neurons

    Brain Research

    (1977)
  • WidenL. et al.

    Effects of corticipetal and corticofugal impulses upon single elements of the dorsolateral geniculate nucleus

    Exp. Neurol.

    (1960)
  • AsheJ.H. et al.

    Mesencephalic multiple unit activity during acquisition of conditioned pupillary dilation

    Brain Res. Bull.

    (1978)
  • BirtD. et al.

    Effects of bilateral auditory cortex ablation on behavior and unit activity in rat inferior colliculus during differential conditioning

    J. Neurophysiol.

    (1978)
  • BuchwaldJ.S. et al.

    Response plasticity in cochlear nucleus of decerebrate cats during acoustic habituation procedures

    J. Neurophysiol.

    (1972)
  • DesmedtJ.E. et al.

    Suppression of acoustic input by thalamic stimulation

  • DesmedtJ.E. et al.

    Corticofugal projections from temporal lobe in cat and their possible role in acoustic discrimination

    J. Physiol. (Lond.)

    (1959)
  • DisterhoftJ.F. et al.

    Differential development of conditioned unit changes in thalamus and cortex of rat

    J. Neurophysiol.

    (1972)
  • DisterhoftJ.F. et al.

    Trial sequence of changed unit activity in auditory system of alert rat during conditioned response acquisiton and extinction

    J. Neurophysiol.

    (1976)
  • GabrielM.

    Short-latency discriminative unit response: Engram or bias?

    Physiol. Psychol.

    (1976)
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    This work was supported by U.S.P.H.S. Grant MH 16978.

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