What effect does GABA have on neural activity?

GABA, or gamma-aminobutyric acid, is the primary inhibitory neurotransmitter in the central nervous system. Its main role is to reduce neuronal excitability throughout the nervous system. When GABA binds to its receptors on neurons, it leads to an influx of chloride ions into the cell, causing hyperpolarization. This process makes it more difficult for the neuron to fire an action potential, effectively stabilizing neural activity by preventing excessive stimulation.

In contrast to the other options, which suggest an increase in activity, arousal, or enhancement, GABA functions to dampen excessive signal transmission, thus promoting a balanced and stable internal environment in the brain. This stabilizing effect is crucial for regulating mood, anxiety, and various cognitive functions, helping to maintain homeostasis within the nervous system.