Exaggerated avoidance of novel stimulation in rats partially recovered from central norepinephrine damage

Rats in which central norepinephrine lesions are made with 6-OHDA and a recovery period allowed show a behavioral syndrome distinct from controls, from rats with more extensive norepinephrine damage (lesioned with 6-OHDA, allowed to recover, and relesioned), and from rats with general depletion of serotonin (chronic PCPA). These rats administered central 6-OHDA injections and then allowed a recovery period rear less in open field than all other groups and are characterized by an exaggerated avoidance of novel visual stimulation in light onset and light escape tests. It is proposed that this reflects the hyperresponsivity of partially repaired, supersensitive norepinephrine circuitry to novel or intense stimulation.