Depolarization, in the context of Computational Neuroscience, refers to a change in a neuron’s membrane potential that makes it less negative (more positive) compared to the resting potential. This process is crucial for the initiation and propagation of electrical signals in neurons.
Process for Action Potential Generation
Before depolarization occurs, a neuron is at its resting membrane potential, typically around -70 millivolts (mV). When a neuron receives a stimulus, such as a neurotransmitter binding to its receptors, it can lead to the opening of ion channels in the neuron’s membrane. This allows positively charged ions (like sodium ions, Na+) to flow into the cell.
Once the influx of positive ions reaches a certain threshold (usually around -55 mV), it triggers an action potential. During an action potential, the membrane potential rapidly rises and becomes positive, often reaching around +30 mV. This rapid change is due to the opening of additional sodium channels, allowing more Na+ ions to enter the cell.