Deciphering the brainstem, hippocampal and whole-brain dynamics by neuronal-ensemble event signatures

Abstract

Intracortically-recorded brain signals display a rich variety of such transient activities: brief, recurring episodes of deflection or oscillatory activities that reflect cooperative neural circuit mechanisms. These network patterns of activity, also called neural events, span multiple spatio-temporal scales, and are believed to be basic computing elements during cognitive processes such as learning and off-line memory consolidation. However, both the large-scale and microscopic-scale cooperative mechanisms associated with these episodes remain poorly understood. This knowledge gap arises partly due to methodological limitations of existing experimental approaches, specifically in measuring simultaneous micro- and macroscopic aspects of neuronal activity in the brain. Therefore, this dissertation sought to study the relationship between ongoing spontaneous neural events in the hippocampus, brainstem and thalamic structures at micro-, meso- and macroscopic scales by combining data from intracortical recordings, multi-compartmental network models, and functional magnetic resonance imaging (fMRI).