Cortical evoked potentials are largely produced by which of the following mechanisms?

Cortical evoked potentials primarily arise from excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) within the cortical neurons. These potentials reflect the summation of synaptic inputs that the cortical neurons receive in response to sensory stimuli or electrical stimulation. When an excitatory neurotransmitter binds to its receptor on a postsynaptic neuron, it results in depolarization, contributing to EPSPs. Inhibitory neurotransmitters can similarly modulate neuronal activity, resulting in IPSPs, which can counteract or refine the excitatory signals.

The generation of cortical evoked potentials reflects the collective activity of these synaptic inputs rather than action potentials propagating along axons or other mechanisms such as high-energy magnetic fields. Therefore, understanding the role of EPSPs and IPSPs is crucial in interpreting cortical evoked potential responses during neurophysiological monitoring.