Nervous system ↗Cues create predictions
Sight, smell, time, place, memory, availability, and learned associations can drive attention and preparatory neural, salivary, gastric, and endocrine responses.
BRAIN & NERVES / 06
Eating is sensed,
learned, and regulated.
Appetite is not controlled by one “hunger hormone.” Sensory prediction, gut mechanics, vagal input, circulating nutrients and peptides, hypothalamic and hindbrain circuits, reward learning, sleep, stress, and food environment converge.
Mouth and gut report arrival
Taste, texture, swallowing, gastric stretch, intestinal nutrients, osmolality, and irritation generate neural and hormonal feedback.
Vagal afferents reach hindbrain
Gut and portal signals travel through vagal pathways toward the nucleus tractus solitarius, where they integrate with humoral inputs and descending context.
Peptides shape meal termination
CCK, GLP-1, PYY, ghrelin, insulin, and other signals act through peripheral and central routes with different timing and functions.
Hypothalamic circuits integrate
Arcuate and connected networks include AgRP/NPY and POMC-related populations that respond to hormones, nutrients, neural input, and energy state.
Adiposity signals add context
Leptin and insulin convey aspects of stored and recent energy context, but common obesity cannot be reduced to simple hormone deficiency or “willpower.”
Reward changes food value
Mesolimbic, cortical, amygdala, hippocampal, and hypothalamic networks learn cue value, effort, novelty, habit, and consequence.
Behavior closes the loop
Sleep, stress, medicines, movement, social context, food access, meal composition, and prior learning alter intake and the signals produced by eating.