Format

Send to

Choose Destination
Hippocampus. 2016 Nov;26(11):1393-1413. doi: 10.1002/hipo.22615. Epub 2016 Jul 22.

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

Author information

1
School of Psychology, Cardiff University, 70 Park Place, Cardiff, Wales, CF10 3AT, United Kingdom. KinnavaneL@cardiff.ac.uk.
2
School of Psychology, Cardiff University, 70 Park Place, Cardiff, Wales, CF10 3AT, United Kingdom.

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.

KEYWORDS:

entorhinal cortex; hippocampus; nucleus reuniens; prefrontal cortex; recognition memory

PMID:
27398938
PMCID:
PMC5082501
DOI:
10.1002/hipo.22615
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center