Dynamic Network Decoding of Working Memory Based on Electrophysiological Signals of Human Brain

The human brain consists of various parts, each with its own specific role in directing behaviors. Even simple tasks involve the coordinated activities of multiple brain regions. Cognitive activities, in general, rely on the ability to retain and adaptively manipulate information. This crucial capability is often attributed to Working Memory (WM). The current study aimed to gain a deeper insight into the neural mechanism of WM and understood how the neural activities were coordinated across brain regions. To achieve this objective, the invasively recorded electrophysiological activities from Medial Temporal (MT) cortex using high number of electrodes were analyzed. The human subjects did a verbal working memory task including three phases: encoding, maintenance and retrieval. Graphs of brain networks were generated using the Phase Locking Value (PLV), a functional connectivity metric, across six conventional frequency bands. In conclusion, a noteworthy observation was made regarding the reinforcement of a majority of brain connections during maintenance. Beta oscillations between the posterior and anterior hippocampus showed increased synchrony during maintenance of WM. This finding opens up the possibility of formulating a hypothesis regarding the flow of information between different brain regions during the maintenance state.