Lateralization of the Morris water maze task was examined by injecting 5 ng of tetrodotoxin (TTX) into one dorsal hippocampus (HPC) of chronically cannulated rats (n = 20). The task, acquired (A) during unilateral HPC block, was retrieved (R) during TTX blockade of the ipsi- (I) or contralateral (C) HPC. Escape latencies (in seconds) at 3 levels of acquisition and in the first 4-trial block of I or C retrieval suggest lateralization was absent after the first block (A = 49, I = 40, C = 44), partial after training to an efficient search strategy (A = 6, I = 9, C = 14), and complete after overtraining to goal-directed escape (A = 4, I = 4, C = 12), as further indicated by comparisons of A vs. R behavior and probe trials. The analyses also indicate that (a) HPC contributes to the acquisition but is unnecessary for retrieval of the procedural engram, (b) overtrained learning with one HPC or intact brain is similar, and (c) there is no left-right hemispheric specialization for place learning.

Institute of Physiology Academy of Sciences of Czech Republic Prague

Citace poskytuje Crossref.org

MK-801 Impairs Cognitive Coordination on a Rotating Arena (Carousel) and Contextual Specificity of Hippocampal Immediate-Early Gene Expression in a Rat Model of Psychosis

Stress-induced out-of-context activation of memory

Behavioral evidence that segregation and representation are dissociable hippocampal functions

Place cells and place navigation