Abstract

What is the contribution of the hippocampal dependent declarative memory system to on-line processing of reference in discourse? WELL ESTABLISHED are the contributions of hippocampus to the formation of new enduring (long-term) memories (Ranganath, 2010; Squire, 1992), and its contributions to relational binding and representational flexibility (Eichenbaum & Cohen, 2001). EMERGING RESEARCH shows that hippocampus additionally contributes to on-line processing, even across minimal delays. Evidence from hippocampal imaging in healthy participants, and behavioral evidence from patients with bilateral hippocampal damage show:- Activation of hippocampus in healthy participants for relational learning over short delays (Hannula & Ranganath, 2008), and during retrieval of items from working memory (Öztekin, McElree, Staresina, & Davachi, 2008).- Degradation of relational representations in patients with bilateral hippocampal lesions over short delays (Hannula, Tranel, & Cohen, 2006) and in the processing of simple stimuli over short delays (Warren, et al. 2010). THE PRESENT RESEARCH examines contributions of hippocampus to discourse:- Our initial findings (Kurczek, Brown-Schmidt, & Duff, 2013) revealed profound deficits in ability of hippocampal amnesic participants to recruit discourse information from one sentence to resolve a pronoun in the subsequent sentence: Mickey is playing the violin for Donald as the sun is shining overhead. He is wearing a yellow bracelet…- Modeled after previous research with healthy participants (Arnold, et al., 2000), we found that unlike healthy matched comparison participants, patients with hippocampal amnesia did not show a significant preference to interpret the pronoun as referring to the 1st-mentioned referent.- Here we ask whether the discourse representation is ENTIRELY LOST in amnesia, or whether it is present, but WEAKENED.