Poster A75, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Detecting neural correlates of autobiographical memory for recent and remote memories through high-resolution fMRI
Farah Naaz1, Lindsay K. Knight1, Brooke N. Siers1, Brendan E. Depue1; 1University of Louisville
There is ongoing debate on the degree of involvement of the hippocampus in recollection of memories. Research suggests increasingly diffuse activation of representations leading to independence from hippocampal processes as memories age; while other researchers theorize that recollection never becomes independent of the hippocampus, but instead may show migration corresponding to the long axis (anterior-posterior). Different theories also suggest that the degree and spatial extent of hippocampal activation is dependent on spatial information. Therefore, it is critical to explore differences in hippocampal activation manipulating both age and spatial content of memory. The current study explores this issue by using autobiographical memories for objects and locations from three time periods: early, teen years, and recent. Twenty participants were scanned using high-resolution functional scans (1.5x1.5x1.5mm). Participants generated 30 unique cues and various ratings for these memories one day before the scan. Results indicate a common trend across types of memories and time periods. Objects and locations activated similar regions of the hippocampus and parahippocampal gyrus, however, the degree of activation was significantly greater for location memories. Similarly, increasing age led to decreased activation in the hippocampus and parahippocampal gyrus in a linear manner. The degree of activation corresponding to manipulations of age can be allocated to self-reported aspects of these memories: recent memories are less difficult to retrieve, were reported to be more vivid, important, and frequently recalled. The current study suggests that the hippocampus appears to always be recruited in recollection, however the level activation varies as a function of age.
Topic Area: LONG-TERM MEMORY: Episodic