Which group of nerve cells releases galanin and GABA to suppress arousal systems?

The ventrolateral preoptic nucleus (VLPO) plays a crucial role in regulating sleep and arousal. This specific group of nerve cells is essential for promoting sleep by releasing the neurotransmitters galanin and GABA (gamma-aminobutyric acid). These neurotransmitters work by inhibiting wake-promoting neurons in various parts of the brain, ultimately suppressing arousal systems.

GABA is known for its inhibitory effects, contributing to reduced neuronal excitability, while galanin also has a role in modulating synaptic transmission. By releasing these neurotransmitters, the VLPO actively promotes sleep and helps facilitate a transition from wakefulness to sleep, providing a balance in the regulatory systems of arousal and rest.

In this context, the other options represent different brain structures with distinct roles. The lateral hypothalamic area (LHA) is more involved in promoting wakefulness and arousal. The ventral tegmental area (VTA) is significant in the reward system and influences arousal through dopaminergic pathways. The suprachiasmatic nucleus (SCN) is primarily known for its role in regulating circadian rhythms rather than directly suppressing arousal. Therefore, the VLPO's function in releasing galanin and