Learning and integration of rewarding and aversive stimuli in the rat lateral hypothalamus

Single neuron activity was recorded in the lateral hypothalamus (LHA) and lateral preoptic-anterior hypothalamic area (IPOA-AHA) of the rat during discrimination learning of cue tones that predicted glucose or intracranial self-stimulation as rewarding stimuli, or electric shock or tail pinch as aversive stimuli, using identical behavior, licking. Rewarding and aversive stimuli had opposite effects on the same LHA neurons, but had the same effects on IPOA-AHA neurons. Neurons in the LHA that differentiated between reward and aversion acquired discrimination of the respective cue tones, while IPOA-AHA neurons responded in the same way to cue tones whether they preceded reward or aversion. The results suggest reward- and aversion-related integrative functions in the LHA and arousal or attentional functions in the IPOA-AHA.