Poster D42, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Oscillatory Synchrony within the Hippocampal-Thalamo-Prefrontal Circuit of the Rat During Spatial Working Memory-Guided Decision Making
Andrew Garcia1, Amy Griffin1; 1University of Delaware
Spatial working memory-guided behavior in the rodent has been shown to be supported by oscillatory synchrony between the hippocampus and the medial prefrontal cortex (mPFC). However, anatomical connections between hippocampus and mPFC are limited to a monosynaptic pathway extending from hippocampus to mPFC. The nucleus reuniens (RE) of ventral-midline thalamus is not only reciprocally connected with both hippocampus and mPFC, but has also been shown to be necessary for spatial WM-guided behavior and hippocampal-mPFC synchrony. To further explore the contributions of RE to oscillatory synchrony within the hippocampal-mPFC circuit, we recorded local field potentials from hippocampus, mPFC, and RE during the delayed nonmatch-to-position task which requires encoding trial-specific information during the sample phase, maintenance across a delay period, and retrieval-guided decision-making during the choice phase. In line with previous reports, we observed higher hippocampal-mPFC theta coherence during the choice phase compared to the sample phase (O’Neill et al., 2013). Coherence between RE and mPFC showed increases in the delta/theta frequency range also specific to the choice phase. Furthermore, these choice phase-specific increases in synchrony were not observed when animals performed the task poorly. Although coherence between RE and hippocampus showed peaks at theta, they were similar in magnitude for sample and choice. Examination of cross-frequency interactions between theta phase and gamma amplitude within RE and between HC and mPFC also showed increases for the choice phase compared to the sample phase. These choice phase-specific oscillatory interactions suggest that distinct patterns of oscillatory synchrony are related to successful sWM-guided behavior.
Topic Area: EXECUTIVE PROCESSES: Working memory