Temporal discrimination learning in abstinent chronic alcoholics

Background: Converging evidence from varied experimental paradigms has demonstrated that the cerebellum is involved in the timing of learned behavior. Given the documented neurological changes secondary to chronic alcoholism, particularly cerebellar degeneration, the ability of recovered chronic alcoholics to learn a temporal discrimination was assessed by using delayed eyeblink classical conditioning. Methods: Twelve abstinent alcoholic participants and 12 matched control participants were randomly presented 2 clearly discriminable tone conditioned stimuli that were individually paired with 2 different interstimulus intervals. Results: The data revealed a significant alteration in the abstinent alcoholics' peak latency measure at the long interstimulus intervals and an overall impairment in their level of acquisition of conditioned responses. No group differences in extinction were observed. Conclusions: It was speculated that cerebellar cortical atrophy caused by years of alcohol abuse resulted in the peak latency alteration and that atrophy extending into deep cerebellar nuclei caused the overall impairment in conditioned response acquisition.