Four-dimensional Mapping of Visuospatial Memory
Abstract number :
1.028
Submission category :
1. Basic Mechanisms / 1C. Electrophysiology/High frequency oscillations
Year :
2022
Submission ID :
2204202
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:23 AM
Authors :
Riyo Ueda, MD, PhD, – Wayne State University; Takumi Mitsuhashi, MD, PhD – Wayne State University; Kazuki Sakakura, MD – Wayne State University; Yu Kitazawa, MD, PhD – Wayne State University; Masaki Sonoda, MD, PhD – Wayne State University; Eishi Asano, MD, PhD – Wayne State University
Rationale: To determine the dynamics of intracranially-recorded high-gamma and alpha modulations underlying visuospatial working memory, and to assess the effect of memory loads on task-related neural dynamics.
Methods: Ten patients with drug-resistant focal epilepsy were assigned to play a Lumosity cognitive training game: ‘Memory Matrix’ during intracranial EEG recording. In each trial, a given patient was presented a grid of tiles on an iPad for 2 seconds (i.e., input period); thereby, three or more tiles within each grid were painted in blue. After the disappearance of paints (i.e., output period), patients needed to tap on the tiles painted before (Figure 1). This game was designed to increase or reduce the number of painted tiles (i.e., memory load) in a trial immediately after a correct or incorrect response, respectively. Each patient played five sessions, each of which included 12 trials. A group-level movie atlas visualized the dynamics of high-gamma (70-110 Hz) and alpha (8-12 Hz) modulations during gameplay. The mixed model analysis determined the factors independently associated with high-gamma and alpha amplitudes at a given epoch.
Results: Increased memory loads were associated with high-gamma augmentation in the medial occipital region for 200 ms post-tile appearance and disappearance. Increased memory loads were associated with high-gamma augmentation in the entorhinal region at 600-800 ms post-tile appearance. Conversely, increased memory loads were associated with high-gamma attenuation and alpha augmentation in extensive areas, including superior-temporal and inferior-frontal gyri, during the entire input and output periods.
Conclusions: High-gamma augmentation in the medial occipital and entorhinal regions may reflect neural engagement required for the visuospatial memory encoding process. Alpha augmentation coupled with high-gamma attenuation in the frontal-temporal networks enhanced in higher memory-load trials may reflect suppression of cortical function unnecessary for working memory encoding.
Funding: NIH grant NS64033 (to E. Asano)
Basic Mechanisms