The medial dorsal thalamic nucleus and the medial prefrontal cortex of the rat function together to support associative recognition and recency but not item recognition

Laura Cross, Malcolm W. Brown, John P. Aggleton, E. Clea Warburton*

*Corresponding author for this work

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

58 Citations (Scopus)

Abstract

In humans recognition memory deficits, a typical feature of diencephalic amnesia, have been tentatively linked to mediodorsal thalamic nucleus (MD) damage. Animal studies have occasionally investigated the role of the MD in single-item recognition, but have not systematically analyzed its involvement in other recognition memory processes. In Experiment 1 rats with bilateral excitotoxic lesions in the MD or the medial prefrontal cortex (mPFC) were tested in tasks that assessed single-item recognition (novel object preference), associative recognition memory (object-in-place), and recency discrimination (recency memory task). Experiment 2 examined the functional importance of the interactions between the MD and mPFC using disconnection techniques. Unilateral excitotoxic lesions were placed in both the MD and the mPFC in either the same (MD + mPFC Ipsi) or opposite hemispheres (MD + mPFC Contra group). Bilateral lesions in the MD or mPFC impaired object-in-place and recency memory tasks, but had no effect on novel object preference. In Experiment 2 the MD + mPFC Contra group was significantly impaired in the object-in-place and recency memory tasks compared with the MD + mPFC Ipsi group, but novel object preference was intact. Thus, connections between the MD and mPFC are critical for recognition memory when the discriminations involve associative or recency information. However, the rodent MD is not necessary for single-item recognition memory.

Original languageEnglish
Pages (from-to)41-50
Number of pages10
JournalLearning and Memory
Volume20
Issue number1
DOIs
Publication statusPublished - Jan 2013

Keywords

  • MEDIODORSAL NUCLEUS
  • NEUROTOXIC LESIONS
  • PERIRHINAL CORTEX
  • OBJECT RECOGNITION
  • FORNIX TRANSECTION
  • TEMPORAL-ORDER
  • MACAQUE MONKEYS
  • MEMORY
  • AMNESIA
  • ORGANIZATION

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