Liuting Zou

1 Introduction Key neuromodulatory systems—dopamine (DA), serotonin (5-HT), acetylcholine (ACh), and norepinephrine (NE)—orchestrate behavioral states and underlie synaptic plasticity during learning and decision-making [1-4]. Each system supports a unique set of processes: DA in reward and motivation, 5-HT in mood and homeostasis, ACh in attention and memory, and NE in alertness and arousal [1-4].

Abstract Active avoidance is a type of instrumental behavior that requires an organism actively to engage in specific actions to avoid or escape from a potentially aversive stimulus and is crucial for the survival and well-being of organisms. It requires a widely distributed, hard-wired neural circuits spanning multiple brain regions, including the amygdala and thalamus. However, less is known about whether and how the hypothalamus encodes and controls active avoidance learning.