The Role of Rhythmic Brain Activity in Long Term Memory Retrieval

34 pages. A thesis presented to the Department of Psychology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Arts, Spring 2015.This study aims to elucidate the relationship between Working Memory (WM) and Long Term Memory (LTM) on a neurological basis. In WM tasks, it has been well documented that the alpha frequency signal (8-12 Hz) occurs at the onset of the stimulus. This study seeks to answer whether or not a similar neural pattern exists during a LTM task when the subject retrieves spatial information and holds it in mind. Additionally, when does this signal occur? I predicted that the alpha signal would reoccur upon retrieval of the spatial stimuli thus revealing a re-representation into working memory. To get at these hypotheses, participants (N=27) participated in a LTM task over the course of two days. Day 1 involved the studying of various objects’ spatial location on a circular array. On day 2, participants were tested on the items and their brain activity recorded. Results revealed that the alpha signal (8-12 hz) indeed did occur upon retrieval of the spatial representation from LTM. The signal occurred at approx. 600 ms and was sustained through the remainder of the trial. These findings suggest that Spatial Working Memory and holding spatial info in mind retrieved from Long Term Memory rely on the same neural mechanism