The Acute Impact of Ethanol on Cognitive Performance in Rhesus Macaques

Abstract

Decreased cognitive control over prepotent responses has been hypothesized to contribute to ethanol-induced behavioral disinhibition. However, the effects of ethanol on specific cognitive domains associated with decision making have not been extensively studied. We examined the impact of acute ethanol administration on cognitive performance of nonhuman primates. Studies were conducted using 0.2, 0.5, and 1 g/kg intravenous ethanol in rhesus macaques performing touch screen-based tasks examining stimulus discrimination, stimulus reversal, and stimulus response performance. The impact on attentional processing was also evaluated. Ethanol reduced the accuracy of reversal performance marginally at 0.2 g/kg and significantly at 0.5 g/kg. This effect was selective given an absence of impairment on the stimulus discrimination and stimulus response tasks at these doses. Performance on stimulus discrimination was impaired at 1.0 g/kg, which prevented determination of reversal performance. Analysis of post-error response times demonstrated that error processing was impaired at both 0.2 and 0.5 g/kg. Ethanol also increased the number of omissions and delayed responses on an attentional task, suggesting more frequent attentional lapses. These data demonstrate that cognitive function mediated by specific prefrontal cortical brain regions is particularly sensitive to ethanol and suggest specific cognitive mechanisms that may underlie harmful decisions made at low doses of ethanol.

Effects of chronic intermittent ethanol exposure on orbitofrontal and medial prefrontal cortex-dependent behaviors in mice.

“…Results of the present study show that, in contrast to its effects on set-shifting, CIE exposure induced deficits in reversal learning that are similar to that reported for human alcoholics (Fortier et al, 2008; Fortier et al, 2009), primates (Jedema et al, 2010) and rodents (Brown et al, 2007; Obernier et al, 2002; Ripley et al, 2003; Thomas et al, 2004; Wainwright et al, 1990). That is, performance during reversal learning was significantly impaired following short-term abstinence from alcohol exposure, as CIE mice required more trials, made more errors and performed worse relative to simple discrimination (baseline) than controls.…”

Chronic Intermittent Ethanol Exposure Enhances the Excitability and Synaptic Plasticity of Lateral Orbitofrontal Cortex Neurons and Induces a Tolerance to the Acute Inhibitory Actions of Ethanol

“…Acute exposure to ethanol disrupts reversal learning in monkeys (Jedema et al, 2011) and rats (Brown et al, 2007), and suppresses electrophysiological activity of lOFC neurons in mice (Badanich et al, 2013). Previous studies in our laboratory also demonstrate that mice exposed chronically to ethanol show impaired performance on a reversal learning task (Badanich et al, 2011) shown to require the lOFC (Bissonette et al, 2008).…”

On the Globality of Motor Suppression: Unexpected Events and Their Influence on Behavior and Cognition

“…In addition to manual responses, PES occurs after erroneous saccades (Endrass et al, 2007), and after responses made with the feet. PES is also observed across age-groups (Brooker and Buss, 2014; Friedman et al, 2009) and species (Jedema et al, 2011; Narayanan and Laubach, 2008). Theories of PES can be coarsely grouped into ‘adaptive’ theories, proposing that PES is aimed at improving ongoing behavior, and ‘maladaptive’ theories, proposing that PES signifies behavioral impairment caused by an error (for detailed reviews, see Danielmeier and Ullsperger, 2011; Ullsperger et al, 2014).…”