Working memory, executive processes and the effects of alcohol on Go/No-Golearning: testing a model of behavioral regulation and impulsivity

Rationale: Impulsivity is associated with increased risk for alcoholism. Al cohol also may increase impulsive behavior, although little is known about the processes underlying this effect. Objectives: This study tested a model proposing that the executive processes of working memory (WM) and conditio nal associative learning (CAL) modulate behavioral inhibition. Subjects had either a positive (FHP) or a negative (FHN) family history of alcoholism. Hypotheses were that alcohol would increase Go/No-Go impulsive responding b ut only in subjects with low working memory capacity (low-WM), low-GAL abil ity, or FHP for alcoholism. The model also predicted that WM and CAL modula te inhibitory responses to contingency reversal on a Go/No-Go task. Methods : A Go/No-Go learning task with a midway contingency reversal was administe red to 71 FHP and 78 FHN subjects when sober and after drinking one of two moderate doses of alcohol. WM (digits backward) and CAL (conditional spatia l association task) were also assessed when sober. Results: Alcohol resulte d in more false alarms but only in low-WM subjects. Both WM and CAL modulat ed learning to inhibit behavior after contingency reversal, suggesting sepa rate modulation mechanisms for WM and GAL. Subjects with low-capacity WM an d subjects with low-capacity CAL ability had more difficulty learning respo nse inhibition after contingency reversal. FHPs and FHNs did not differ in their response to alcohol. Conclusions: The results support our model of th e modulatory role of WM and CAL in the ongoing regulation of behavioral inh ibitory systems. The results also suggest that individuals with low capacit y WM are more susceptible to alcohol's effect of increasing impulsive behav ior, suggesting that alcohol reduces the capacity of working memory to modu late response inhibition.