Pineal lesion produces bilateral visual and auditory inattention in the rat.

Unilateral lesions in such brain regions as medial frontal cortex and superior colliculus produce polysensory neglect contralateral to the lesion. Since the pineal gland is an unpaired brain structure, both electrophysiologically and hormonally responsive to visual and auditory stimulation, it may modulate bilateral sensory attention mechanisms. Long-Evans male rats were given pineal or sham lesions and were tested behaviourally. Sensory assessment revealed that in comparison to sham animals rats with pineal lesion exhibited unilateral visual and auditory neglect to stimuli presented on either side of the body. Animals with pineal lesions were more likely than sham-lesioned animals to demonstrate visual allesthesis and, compared to sham-lesioned rats, showed extinction on the left side to bilateral simultaneous visual stimulation. This is the first report that midline neuroendocrine damage can produce bilateral sensory inattention.