PhD Research

Precision neuromodulation is a powerful tool for interrogating brain circuits and the multitude of functions that they support. Although the specific neural substrates and coordinated patterns of activity that give rise to these functions are increasingly understood, considerably less is known about the neurophysiological consequences of stimulating the brain directly. This is especially true concerning recent efforts toward developing a neural prosthesis for episodic memory—although specific patterns of neural activity have been linked to different episodic memory processes, brain stimulation for memory enhancement has nonetheless yielded highly heterogeneous effects.

The goal of my PhD research was to characterize the diverse, multiscale repertoire of neural dynamics evoked by direct electrical stimulation—spanning the level of individual neurons to distributed brain networks. Leveraging intracranial electroencephalography recordings and various forms of direct electrical stimulation, I transiently perturbed endogenous neural activity and characterized evoked responses at the micro-, meso-, and macroscale. Our findings provided unambiguous evidence that direct electrical stimulation may exert widespread modulatory effects spanning multiple scales—manipulating the firing rates of individual neurons, influencing the power of regional low-frequency oscillations, and triggering evoked potentials that propagate throughout the brain with a traveling-wave-like motif.