Coupled effects of channels and synaptic dynamics in stochastic modelling of healthy and Parkinson's-disease-affected brains

TL;DR

This paper investigates how stochastic influences, including random inputs and refractory periods, affect neuronal activity in the subthalamic nucleus, providing insights into Parkinson's disease mechanisms and treatment effects like deep brain stimulation.

Contribution

It introduces a stochastic model of STN neuron dynamics considering channels and synaptic effects, highlighting their coupled impact on healthy and Parkinsonian brains.

Findings

Random inputs significantly alter spike train irregularity.

Refractory periods influence neuronal response variability.

Stochastic effects are crucial in understanding PD neuron behavior.

Abstract

Our brain is a complex information processing network in which the nervous system receives information from the environment to quickly react to incoming events or learns from experience to sharp our memory. In the nervous system, the brain states translate collective activities of neurons interconnected via synaptic connections. In this paper, we study coupled effects of channels and synaptic dynamics under the stochastic influence of healthy brain cells with applications to Parkinson's disease (PD). In particular, we investigate the effects of random inputs in a subthalamic nucleus (STN) cell membrane potential model. The STN bursting phenomena and parkinsonian hypokinetic motor symptoms are closely connected, as electrical and chemical maneuvers modulating STN bursts are sufficient to ameliorate or mimic parkinsonian motor deficits. Deep brain stimulation (DBS) of the STN is an important surgical technique used in the treatment to improve PD symptoms. Our numerical results show that the random inputs strongly affect the spiking activities of the STN neuron not only in the case of healthy cells but also in the case of PD cells in the presence of DBS treatment. Specifically, the existence of a random refractory period together with random input current in the system may substantially influence an increased irregularity of spike trains of the output neurons.