Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Health Science

Faculty/School

Faculty of Science

First Advisor

Nicolas Rouleau

Advisor Role

Thesis supervisor

Second Advisor

Nirosha J. Murugan

Third Advisor

Bruce McKay

Abstract

Endogenous brain rhythms guide neural communication and plasticity, raising the question of whether weak, temporally structured electromagnetic fields (EMFs) that mimic these rhythms can modulate neuronal activity in a targeted, biomimetic manner. This thesis investigates whether patterned EMFs designed to reflect the temporal structure of hippocampal long-term potentiation (LTP) are more effective at inducing neural plasticity than conventional sinusoidal fields or no stimulation at all. Cortical neurons cultured from postnatal rats were exposed to patterned EMFs for 30 minutes and assessed across three distinct experimental domains. In Chapter 2, microelectrode array (MEA) recordings revealed that the LTP-patterned field significantly increased burst spiking and evoked response amplitudes, effects abolished by NMDA receptor antagonism, indicating involvement of canonical plasticity pathways. Chapter 3 examined immediate early gene expression following stimulation. While several plasticity associated genes showed no change, c-jun expression was selectively elevated in the LTP field group, suggesting that brief but synchronous activity may selectively initiate certain transcriptional programs. In Chapter 4, we used immunofluorescence to quantify synaptic remodeling, showing increased colocalization of PSD-95 and synaptophysin in neurons exposed to the LTP pattern, consistent with enhanced synaptogenesis. Collectively, these findings demonstrate that low-intensity EMFs patterned on physiological firing can enhance functional, molecular, and structural correlates of synaptic plasticity more effectively than non-biological waveforms. This supports a resonance-based model of neuromodulation in which neurons respond not only to field strength but to the temporal information embedded in the stimulation itself. These results offer a new approach to brain stimulation that may have clinical applications in neural repair, learning, and memory enhancement.

Convocation Year

2025

Convocation Season

Fall

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