Poster A84, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Hippocampus is necessarily involved in recollection memory precision
Aneesha S Nilakantan1, Donna J Bridge1, John A Walker1, Stephen A VanHaerents1, Joel L Voss1; 1Northwestern University Feinberg School of Medicine
Episodic recollection depends critically on the hippocampus. Recollection is often measured with source memory tests in which participants are asked to recall the context in which an object was studied. However, even when recollection is successful (e.g., “I parked my car at the museum”), the quality of information and details recollected vary (e.g., “I parked my car at the museum on the left on the fourth floor”). Most studies explore memory success but do not consider the varying amounts of detail (memory precision) recalled. The neural processes and the role of the hippocampus in recollection precision relative to success are unclear. Because diminished hippocampal integrity has been associated with recollection impairments, we assessed precision in healthy aging and following unilateral mesial temporal lobe (including hippocampus) resection. 18 young adults (18-35 years-old), 18 older adults (65-80 years-old) and 9 resection patients (31-51 years-old) participated in an associative object-location memory study, designed to segregate memory success from memory precision. Distance error was modeled for each group, resulting in a group-specific recollection threshold. Success was defined as trials with error below this threshold. Within successfully recollected trials, precision was defined as the mean distance error. Recollection success was relatively well matched among groups (with a difference for resection patients versus young adults at p=0.045). However, relative to young adults recollection precision was significantly impaired for older adults (p<0.001) and resection patients (p=0.002). Reductions in recollection precision for older adults and hippocampal resection patients provide evidence that the hippocampus necessarily contributes to memory precision.
Topic Area: LONG-TERM MEMORY: Episodic