PhD Student Zeinab Esmaeilpour presents her second exam - Friday April 2, 2021

Zeinab Esmaeilpour, a PhD student in the lab of Dr. Marom Bikson will present her defense of her research proposal on Friday, April 2, 2021 at 3pm. A copy of her abstract is below. If you would like to attend, please contact Zeinab at zesmaei000@citymail.cuny.edu for the Zoom meeting ID.

Abstract

Understanding the cellular mechanism of direct current (DC) and kilohertz (kHz) electrical stimulation is of broad interest in neuromodulation in both invasive and noninvasive methods. More specifically there is large mismatch between enthusiasm to for clinical applications of the methods and understanding of DC and kHz mechanism of action. In the case of kilohertz stimulation, there is a well-established and validated low pass filtering characteristics of neuronal membrane. This feature attenuates sensitivity of nervous system to any waveforms with high frequency components. On the contrary, kilohertz stimulation has revolutionized spinal cord stimulation and even generated promising results in transcranial stimulation.

Effects DC stimulation have been studied in neuronal depolarization/hyperpolarization, synaptic plasticity and neuronal network modulation. Recent evidence suggests that DC stimulation can induce polarity dependent water exchange across blood brain barrier (BBB) in cell culture experiments through a mechanism called electroosmosis. Modulating water exchange rate across BBB is of broad interest in neurological disease such as dementia, Alzheimer’s, and stroke where brain clearance system is disrupted. Investigating effect of electrical stimulation on water exchange across BBB can potentially lead to therapeutic pathways.

This dissertation provides the first direct in vitro evidence on acute effects kilohertz electrical stimulation in central nervous system using both unmodulated and Amplitude-modulated waveforms. While supported by membrane characteristic of neurons, we uncovered that using low kilohertz stimulation diminishes the sensitivity of hippocampal neurons to electrical stimulation. Moreover, using Amplitude-Modulated waveform can generate a different pattern of modulation and even higher sensitivity to stimulation. However, required electric field in this case is significantly higher than low frequency stimulation methods such as tACS. We plan to study effect of direct current stimulation on water exchange rate across blood brain barrier (BBB) as new avenue of mechanism for electrical stimulation. We will investigate whether tDCS can increase water exchange rate and blood flow in healthy population using and advanced MR imaging technique.