Higher nervous activity in cats with midpontine pretrigeminal transections.

In cats with midpontine pretrigeminal transections, orientation reflexes to visual stimuli consist only of vertical eye movements, pupillary dilation, and electroencephalographic arousal. Extinction of the orientation reflex by repetition of the photic stimulus is easily obtained; the reflex partially recovers after a few minutes of rest. By using as reinforcement stimulation of hypothalamus producing pupillary dilation and EEG arousal, conditioned responses to a visual stimulus may be obtained. The cat with midpontine pretrigeminal transection can be used as convenient preparation for the study of the orientation and conditioned reflexes.