Hippocampal oscillatory signatures of spatial working memory processes during a novel visuo-tactile working memory dependent-conditional discrimination task
Date
2017
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Publisher
University of Delaware
Abstract
Spatial working memory is defined as the encoding, maintenance and retrieval of relevant information to guide goal-oriented navigation. The hippocampus has long been known to be a critical brain region in spatial working memory processes. Oscillatory synchrony between the hippocampus and disparate brain structures critical for SWM has also been heavily researched. What has not been explored are the intrahippocampal oscillatory network dynamics specific to the encoding, maintenance and retrieval processes of spatial working memory. In the present study, in vivo electrophysiological local field potential recordings from the dorsal hippocampus in rats were conducted as they performed two tasks; Conditional Discrimination Standard Task and Working Memory Dependent Conditional Discrimination Task (CDWM). These two tasks differ solely in their working memory demand, such that the Conditional Discrimination Standard task is working memory independent and the latter task is dependent upon working memory for successful performance while both utilize removable inserts which serve as cues for the reward contingency. A threshold was set for “good” performance at 75% correct, dividing all of the recorded sessions of both tasks into two categories based on performance (good vs. poor). This novel dual task allows for a more accurate comparison of hippocampal network dynamics specific to spatial working memory and moreover, to specific working memory processes since the working memory variant task can be broken into distinct encoding (cued) and retrieval (uncued) phases
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Keywords
Biological sciences, Hippocampus, Oscillations, Spatial working memory