You are cordially invited to the following PhD. Thesis Defense Seminar by Bilal Orkan OLCAY.

Title: ON THE CHARACTERIZATION OF MOTOR IMAGERY FUNCTIONS BASED ON SYSTEMATIC TIMING ORGANIZATION OF THE HUMAN BRAIN

Date & Time: Monday, July 12th, 2021, 11:00

Abstract: The main objective of this thesis is to analyze the timing organization of the brain. It is known that brain adapts its localized and also the reciprocal operations for each different cognitive task adaptively. This flexibility of the brain has attracted considerable interest in neuroscience discipline. However, due to the dynamically changing and nonlinear nature of the brain, identification of the timing adaptation property of the brain is remains as an unresolved problem. Our main aim is to capture and use the timing organization of brain for motor imagery activity characterization, by considering timing adaptation of brain, despite the recent BCI methods, consistent activity characterization may become possible. To that end, first, we propose motor imagery activity characterization method that captures the activity-specific time lag between EEG signals. These time lags are then used for recognizing the motor imagery functions of interest. Thereafter, we develop our strategy and propose another method that captures the timings of activity-specific short-lived synchronization between EEG signals. These two methods use channel synchronization for characterization that requires relatively long computation time. To solve this problem, we propose two methods that characterize task-related brain activities by capturing the timings of the activity-specific entropies of EEG signals. In order to show the efficacy of the proposed methods in this thesis, we use online available BCI datasets. The performance results stress that considering the timing organization of the brain is crucial for accurate characterization of cognitive activity, more importantly, it may solve the inconsistency of BCI performance obtained from different subjects.