The effects of radiofrequency lesion or transection of the fimbria- fornix on latent inhibition in the rat

B. Pouzet, C. L. Veenman, B. K. Yee, J. Feldon*, I. Weiner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Latent inhibition consists of a decrement in conditioning to a stimulus as a result of its prior non-reinforced pre-exposure. Based on evidence pointing to the involvement of the hippocampus and the nucleus accumbens in latent inhibition disruption, it has been proposed that latent inhibition depends on the integrity of the subicular input to the nucleus accumbens. Since fibers originating in the subiculum and destined for the nucleus accumbens run through the fimbria-fornix, we assessed the effects of radiofrequency lesion or transection of the fimbria-fornix, on latent inhibition. The effectiveness of both lesions was demonstrated by the total disappearance of acetylcholinesterase staining in the hippocampus and of retrogradely labeled cells in the hippocampus/subiculum following the injection of the retrograde tracer biotin-dextran amine into the shell subregion of the nucleus accumbens. Likewise, in accord with previously documented behavioral effects of lesions to the hippocampus and related structures, both lesions increased spontaneous activity and disrupted performance in Morris water maze, and the radiofrequency lesion facilitated the acquisition of two-way active avoidance. In spite of the above, latent inhibition remained unaffected by both fimbria-fornix lesions, indicating that the critical projections subserving latent inhibition are not those traversing the fimbria-fornix from the hippocampus/subiculum to the nucleus accumbens. The implications of these results for the neural circuitry of latent inhibition and the latent inhibition model of schizophrenia are discussed.

Original languageEnglish
Pages (from-to)1355-1368
Number of pages14
JournalNeuroscience
Volume91
Issue number4
DOIs
StatePublished - Jul 1999

Funding

FundersFunder number
Swiss Federal Institute of Technology, Zurich
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung

    Keywords

    • Fimbria-fornix lesion
    • Latent inhibition
    • Morris water maze
    • Schizophrenia
    • Two-way active avoidance

    Fingerprint

    Dive into the research topics of 'The effects of radiofrequency lesion or transection of the fimbria- fornix on latent inhibition in the rat'. Together they form a unique fingerprint.

    Cite this