Theories / hormones

James-Lange theory - emotions arise from our awareness of our specific bodily responses to emotion-arousing stimuli 

Cannon-Bard theory - emotion arousing stimuli trigger our bodily responses and simultaneous subjective experience 

Schachter-Singer theory - our experience of emotion depends on two factors: general arousal and a conscious cognitive label

leptin - tells the brain that sufficient fat stores exist, thus signaling satisfaction

ghrelin - secreted by empty stomach, signals to brain “I’m hungry”

PYY - hormone to say “I’m not hungry”

orexin  - triggers hunger, secreted by hypothalamus