Detecting and discriminating novel objects: The impact of perirhinal cortex disconnection on hippocampal activity patterns

Lisa Kinnavane, Eman Amin, Cristian M Olarte-Sánchez, John P Aggleton

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Perirhinal cortex provides object-based information and novelty/familiarity information for the hippocampus. The necessity of these inputs was tested by comparing hippocampal c-fos expression in rats with or without perirhinal lesions. These rats either discriminated novel from familiar objects (Novel-Familiar) or explored pairs of novel objects (Novel-Novel). Despite impairing Novel-Familiar discriminations, the perirhinal lesions did not affect novelty detection, as measured by overall object exploration levels (Novel-Novel condition). The perirhinal lesions also largely spared a characteristic network of linked c-fos expression associated with novel stimuli (entorhinal cortex→CA3→distal CA1→proximal subiculum). The findings show: I) that perirhinal lesions preserve behavioral sensitivity to novelty, whilst still impairing the spontaneous ability to discriminate novel from familiar objects, II) that the distinctive patterns of hippocampal c-fos activity promoted by novel stimuli do not require perirhinal inputs, III) that entorhinal Fos counts (layers II and III) increase for novelty discriminations, IV) that hippocampal c-fos networks reflect proximal-distal connectivity differences, and V) that discriminating novelty creates different pathway interactions from merely detecting novelty, pointing to top-down effects that help guide object selection. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.

Original languageEnglish
Pages (from-to)1393-1413
Number of pages21
JournalHippocampus
Volume26
Issue number11
DOIs
Publication statusPublished - Nov 2016

Keywords

  • Analysis of Variance
  • Animals
  • Cell Count
  • Discrimination, Psychological/physiology
  • Exploratory Behavior/physiology
  • Hippocampus/anatomy & histology
  • Maze Learning/physiology
  • Neural Pathways/physiology
  • Oncogene Proteins v-fos/metabolism
  • Perirhinal Cortex/injuries
  • Rats
  • Recognition, Psychology/physiology

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