Excitation and inhibition

Neurons can be broadly classified into two functional types, excitatory and inhibitory, based on their neurotransmitters. The balance between excitation and inhibition in the brain is a fundamental principle of neural circuit function.⁵ It refers to the dynamic equilibrium between excitatory signals, which increase the likelihood of neuronal firing (mainly mediated by glutamate), and inhibitory signals, which decrease that likelihood (primarily mediated by GABA).⁵ Maintenance of the excitation–inhibition balance of the brain is crucial for its functioning.⁵ Indeed, many neurological and psychiatric disorders can involve a disruption to the excitation–inhibition balance, including epilepsy, and schizophrenia.⁵