Location
MC 6460
Candidate
Maxwell Yue | Applied Mathematics, University of Waterloo
Title
Acetylcholine Modulates Hippocampal Theta Oscillations via Regulation of the H-Current
Abstract
Recent experimental evidence shows that muscarinic acetylcholine receptor (mAChR) activation upregulates the h-current in hippocampal pyramidal neurons, inducing subthreshold resonance at theta frequencies. Here, we investigate how acetylcholine (ACh)-mediated h-current modulation affects neuronal resonance, from the single-neuron level in both subthreshold and spiking regimes to the network level, providing insight into how cholinergic modulation may cascade from subthreshold resonance to theta oscillations in neural circuits.
Using established conductance-based neuron models, we represent cholinergic modulation as an increase in the maximal h-current conductance. Bifurcation analysis shows that mAChR activation induces a Bogdanov-Takens bifurcation, switching neurons from type I to type II excitability. To characterize subthreshold resonance, we compute impedance profiles from linearized model simulations with sinusoidal inputs, revealing that the induced resonance is largely independent of the bifurcation structure and the local dynamics near the resting-state equilibrium. We further investigate resonance in the spiking regime by applying sinusoidal currents with suprathreshold amplitude . Building on these single-neuron findings, we aim to examine how ACh-induced h-current upregulation influences resonance and synchronization at the network level.