Poster B70, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Hippocampal-Thalamic Contributions to Associative Memory.
Kirk T. Geier1, Rosanna K. Olsen1,2; 1Rotman Research Institute, 2University of Toronto
Damage to anterodorsal thalamic subregions in rodents and humans can result in memory impairments or even amnesia (Aggleton et al., 2011). fMRI can determine the extent to which these thalamic subregions are involved in different memory processes. To our knowledge, only one previous fMRI study has specifically examined thalamic subregion activity during associative memory (Pergola et al., 2013). The current study uses fMRI (n=28) with concurrent eye-tracking to test the involvement of medial temporal lobe (MTL) and thalamic structures during associative memory (task adapted from Hannula and Ranganath, 2009). Face-scene pairs are encoded during the study phase and then during test trials, a studied scene appears and prompts the participant to retrieve the associated face and hold it in mind. After a brief delay, the scene reappears and participants select among three studied faces the face previously associated with the scene. Faces which were previously associated with the current scene (called “match” faces) were visually sampled significantly more than lure faces, even during incorrect trials, replicating previous results. However, we failed to observe heightened signal in the MTL associated with disproportionate viewing of match faces. During the delay phase (following the scene retrieval cue), significant activations were observed (p<0.05 FDR corrected) within the thalamus, dorsal striatum and ventral visual processing stream. These initial results, however, indicated activity in the thalamic subregions was not strongly associated with memory performance. Further research is thus needed to determine the exact contributions of thalamic subregions along with the MTL to distinct types of memory.
Topic Area: LONG-TERM MEMORY: Episodic