Acute alcohol effects on contextual memory BOLD response: differences based on fragmentary blackout history.

BACKGROUND: Contextual memory, or memory for source details, is an important aspect of episodic memory and has been implicated in alcohol-induced fragmentary blackouts (FBs). Little is known, however, about how neural functioning during contextual memory processes may differ between individuals with and without a history of FB. This study examined whether neural activation during a contextual memory task differed by history of FB and acute alcohol consumption.
METHODS: Twenty-four matched individuals with (FB+; n = 12) and without (FB-; n = 12) a history of FBs were recruited from a longitudinal study of alcohol use and behavioral risks and completed a laboratory beverage challenge followed by 2 functional magnetic resonance imaging (fMRI) sessions under no alcohol and alcohol (breath alcohol concentration = 0.08%) conditions. Task performance and brain hemodynamic activity during a block design contextual memory task were examined across 48 fMRI sessions.
RESULTS: Groups demonstrated no differences in performance on the contextual memory task, yet exhibited different brain response patterns after alcohol intoxication. A significant FB group by beverage interaction emerged in bilateral dorsolateral prefrontal cortex and posterior parietal cortex with FB- individuals showing greater blood oxygenation level-dependent response after alcohol exposure (p < 0.05).
CONCLUSIONS: Alcohol had differential effects on neural activity for FB+ and FB- individuals during recollection of contextual information, perhaps suggesting a neurobiological mechanism associated with alcohol-induced FB.