Gamma and Alpha Band Power Capture Multiple Mechanisms of Variability in Memory Encoding

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Jacqueline Kim¹ (jsk422@cornell.edu), Adam Broitman², Khena Swallow¹; ¹Cornell University, ²University of Pennsylvania

Variability in attention can influence memory encoding over short time scales (e.g., orienting to sudden changes in the environment), or across more extended periods (e.g., sustaining attention to a task, dividing attention across multiple tasks). However, the neural mechanisms underlying the interaction between episodic encoding and temporal changes in attention remain poorly understood. We investigated changes in scalp EEG spectral power as attention varied across multiple time scales. Participants memorized lists of words presented with colored squares and then performed free recall after a brief delay. Some participants memorized the words as a single task, and others pressed a button for a pre-specified square color (target detection task). We observed greater gamma band power (30-100 Hz) early relative to later in lists and prior to the appearance of words that were successfully encoded during single-task and target trials, but not distractor trials. Furthermore, alpha band power (8-13 Hz) increased as more list items were presented and decreased following the presentation of target trials in the dual-task condition, particularly when the coinciding word was later successfully recalled. Spectral power in the gamma and alpha frequency bands may capture discrete neural mechanisms by which variability in attention over time impacts memory encoding.

Topic Area: LONG-TERM MEMORY: Episodic