Neuroimaging studies have demonstrated reduction of hippocampal volume in alcoholics compared with control subjects (Agartz et al 1999; Laakso et al 2000; Pfefferbaum and Sullivan 2002; Bleich, Sperling, et al 2003; Bleich, Wilhelm, et al 2003). One MRI study measured volumes of the HP in late-onset alcoholics (Type 1) and violent early-onset alcoholics (Type 2) compared with nonalcoholic controls. The right, but not left, HP was significantly smaller in both alcoholic groups. While there was no correlation between the hippocampal volumes with age in the control subjects, there was tendency towards decreased volumes with aging and also with the duration of alcoholism in the Type 1 alcoholic subjects (Laakso et al 2000). Activity in the right HP decreased the more remote the autobiographical memories; the gradient of this decrease spanned decades. (Eleanor et al 2003). This suggested that the right HP remains active for memories that are 5 or even 10 years old, and likewise for memories 30 years old, albeit to a much lesser degree.
