Anterior thalamic discriminative neuronal responses enhanced during learning in rabbits with subicular and cingulate cortical lesions.

The neuronal discharge that develops in the anterior ventral thalamic nucleus (AVN) in response to a task-relevant stimulus during learning is enhanced in rabbits with damage in the cingulate and subicular (hippocampal) cortical areas that project to this nucleus. These results indicate that the corticothalamic projections limit the anterior thalamic response but they do not appear to contribute causally to its development. Thus, the discriminative neuronal response is owed to interactions that occur wholly within the subcortical domain of the AVN. The production of this neural code for significant stimuli may be the principal function of the AVN. The enhanced thalamic discharges may be a neural cause of behavioral hyperactivity in animals and amnesia in humans with hippocampal damage.