Int. J. Environ. Res. Public Health 2009, 6, 2007-2027; doi:10.3390/ijerph6072007 OPEN ACCESS International Journal of Environmental Research and Public Health ISSN 1660-4601 www.mdpi.com/journal/ijerph Article Silent Trace Eliminates Differential Eyeblink Learning in Abstinent Alcoholics Catherine Brawn Fortier 1,2,*, Arkadiy L. Maksimovskiy 1, Jonathan R. Venne 1, Ginette LaFleche 3 and Regina E. McGlinchey 1,2 1 Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System; Boston, MA, USA; E-Mails: amaksim@heartbrain.com (A.L.M.); jvenne@heartbrain.com (J.R.V.) 2 Department of Psychiatry, Harvard Medical School; Boston, MA, USA; E-Mail: Regina_McGlinchey@hms.harvard.edu 3 Memory Disorders Research Center (MDRC), Boston University School of Medicine & VA Boston Healthcare System; Boston, MA, USA; E-Mail: glafleche@bu.edu * Author to whom correspondence should be addressed; E-Mail: Catherine_Fortier@hms.harvard.edu; Tel.: +1-857-364-4361 Received: 19 June 2009 / Accepted: 10 July 2009 / Published: 20 July 2009 Abstract: Chronic alcoholism has profound effects on the brain, including volume reductions in regions critical for eyeblink classical conditioning (EBCC). The current study challenged abstinent alcoholics using delay (n = 20) and trace (n = 17) discrimination/reversal EBCC. Comparisons revealed a significant difference between delay and trace conditioning performance during reversal (t (35) = 2.08, p < 0.05). The difference between the two tasks for discrimination was not significant (p = 0.44). These data support the notion that alcoholics are increasingly impaired in the complex task of reversing a previously learned discrimination when a silent trace interval is introduced. Alcoholics’ impairment in flexibly altering learned associations may be central to their continued addiction. Keywords: alcohol; eyeblink classical conditioning; learning; discrimination; reversal