Hippocampal contributions to discourse processing: Findings from Amnesia
Brown-Schmidt, S., Kurczek, J., & Duff, M.C. (2014, March). Hippocampal contributions to discourse processing: Findings from amnesia.Poster presentation at the 26th Annual CUNY Conference on Human Sentence Processing, Columbia, SC.
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...
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- 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.
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- HereweaskwhetherthediscourserepresentationisENTIRELYLOSTinamnesia, or whether it is present, but WEAKENED.