title: Functional dissociation within the entorhinal cortex for memory retrieval of an association between temporally discontiguous stimuli.
abstract: Anatomical connectivity and single neuron coding suggest a segregation of information representation within lateral (LEC) and medial (MEC) portions of the entorhinal cortex, a brain region serving as the primary input/output of the hippocampus and maintaining widespread connections to many association cortices. The present study aimed to expand this idea by examining whether these two subregions differentially contribute to memory retrieval for an association between temporally discontiguous stimuli. We found that reversible inactivation of the LEC, but not the MEC, severely impaired the retrieval of the recently and remotely acquired memory in rat trace eyeblink conditioning, in which a stimulus-free interval was interposed between the conditioned and unconditioned stimulus. Conversely, inactivation of the LEC had no effect on retrieval in delay eyeblink conditioning, where two stimuli were presented without an interval. Therefore, the LEC, but not the MEC, plays a long-lasting role in the retrieval of a memory for an association between temporally discontiguous stimuli.
authors.affiliation: Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Morrissey
authors.forename: Geith
authors.initials: G
authors.lastname: Maal-Bared
authors.forename: Sinead
authors.initials: S
authors.lastname: Brady
authors.forename: Kaori
authors.initials: K
authors.lastname: Takehara-Nishiuchi
mesh_terms: D000161:Acoustic Stimulation / Q000009:adverse effects; D000704:Analysis of Variance; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology*; D003215:Conditioning, Eyelid / Q000187:drug effects / Q000502:physiology*; D004576:Electromyography; D004597:Electroshock / Q000009:adverse effects; D018728:Entorhinal Cortex / Q000502:physiology*; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D008297:Male; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology*; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D013997:Time Factors
chemical_list: D058785:GABA-A Receptor Agonists; D009118:Muscimol