Cortical excitability refers to the level of responsiveness or activity of neurons in the cerebral cortex, which is the outer layer of the brain responsible for higher cognitive functions. Researchers in this area study how factors such as neurotransmitters, electrical stimulation, and neuromodulation techniques can influence the excitability of cortical neurons. Understanding cortical excitability can provide insights into various neurological and psychiatric conditions, as well as inform the development of treatments such as brain stimulation therapies for disorders like depression, epilepsy, and stroke rehabilitation.