Effects of Alcohol on Performance on a Distraction Task During Simulated Driving

Autor: Kathryn C Ruopp, Allyssa J. Allen, Shashwath A. Meda, Robert S. Astur, Vince D. Calhoun, Godfrey D. Pearlson, Pawel Skudlarski
Rok vydání: 2009
Předmět:
Zdroj: Alcoholism: Clinical and Experimental Research. 33:617-625
ISSN: 1530-0277
0145-6008
Popis: A comprehensive analysis of traffic accidents involving alcohol showed that accidents were more likely to occur when drivers with a high blood alcohol concentration (BAC) were performing a secondary task shortly before the accident; alcohol exacerbated the negative effects of such distraction (Brewer and Sandow, 1980). However, the brain mechanisms underlying this phenomenon have not been thoroughly studied. The use of virtual reality driving paired with a secondary attention task during a functional magnetic resonance imaging (fMRI) scan, as was used in this study, may help elucidate the neural mechanisms behind this observation. Visual oddball (VO) paradigms are often used to measure attention. The “classic” format of a VO task consists of stimuli presented visually to a subject at a constant interval. The stimuli are either standard stimuli (occurring frequently) or target stimuli (occurring infrequently); subjects respond when the target stimuli appear (Ardekani et al., 2002). The VO task used in this study is similar to the classic format, except that it was performed while subjects drove in a naturalistic custom built simulator. Previous fMRI studies using VO tasks have identified many regions of brain activation while attending to target stimuli. Most consistently, studies have reported activations in the bilateral supramarginal gyri (Ardekani et al., 2002; Brazdil et al., 2007; Clark et al., 2000; Kiehl and Liddle, 2001; Linden et al., 1999; Mccarthy et al., 1997; Menon et al., 1997; Rangaswamy et al., 2004; Yoshiura et al., 1999) and anterior cingulate cortex (Ardekani et al., 2002; Brazdil et al., 2007; Clark et al., 2000; Crottaz-Herbette and Menon, 2006; Fichtenholtz et al., 2004; Kiehl and Liddle, 2001; Linden et al., 1999; Mccarthy et al., 1997). Activations are also reported in the thalamus (Ardekani et al., 2002; Benar et al., 2007; Clark et al., 2000; Linden et al., 1999;Menon et al., 1997; Rangaswamy et al., 2004; Yoshiura et al., 1999), insula (Ardekani et al., 2002; Benar et al., 2007; Rangaswamy et al., 2004), and inconsistently among, cerebellum (Brazdil et al., 2007; Clark et al., 2000), prefrontal cortex (Brazdil et al., 2007; Corbetta et al., 1991), and hippocampus (Crottaz-Herbette et al., 2005). Although there is no clear consensus in previous fMRI studies as to which brain areas are activated by VO tasks, certain areas were noted in most studies. These areas include the bilateral supramarginal gyri and the anterior cingulate cortex, 2 regions that are commonly linked to attention, with the supramarginal gyrus more specifically linked to spatial orientation (Lacquaniti et al., 1997). Although this study did not use a “classic” VO paradigm, the above mentioned previous research provided the basis for brain areas we looked at in our analysis. To our knowledge, no prior study has examined the effects of alcohol intoxication on functional and behavioral performance of the VO task. However, a few studies have measured alcohol effects on the P300 component (Colrain et al., 1993; Zuzewicz, 1981; Rohrbaugh et al., 1987, Wester et al., 2007), the endogenous component of evoked potential previously shown to be linked with the cerebral information processing neural mechanisms (Pritchard, 1981) of the visual evoked potential. Electrophysiologically, these studies showed increased P300 latency with increased alcohol dosage, while behaviorally showing reaction time (RT) increases with increased alcohol dosage but no significant change in errors (Colrain et al., 1993; Rohrbaugh et al., 1987). In addition, a recent study (Wester et al., 2008) examined the effects of a secondary task during simulated driving and found no differences in errors, but increases in RT. Also, Fillmore and Selst Van (2002) found increased RT, with increased alcohol dose, in a dual-task performance under alcohol challenge. In addition, there have been studies on effects of acute alcohol intoxication on divided attention (Schreckenberger et al., 2004; Schulte et al., 2001). Similar to the studies on VO distraction tasks, Schulte et al. (2001) showed slower RTs with increased intoxication. Schreckenberger et al. (2004) also showed activations in bilateral striatum and frontal cortex, with deactivations in the occipital cortex. The purpose of this study was to examine the neural correlates of acute alcohol effects on driving performance under divided attention conditions. Functionally, based on previous findings in the above-mentioned P300 studies, we hypothesized that there would be dose-related activation decreases in all variables measured (oddball vs. standard, oddballs only, and standards only), in brain areas previously shown to activate during VO tasks. We particularly expect to find this pattern in regions that are involved with attentional processes such as the anterior cingulate cortex, which is specifically involved in error detection (Bush et al., 2000). Also, we expected to find the same activation patterns in additional brain regions not identified in the “classic” VO tasks, such as those found by Schreckenberger et al. (2004) as our paradigm involved additional complex processing skills (e.g., driving, divided attention). Behaviorally, based on the previous literature, we predicted increased RT during VO performance, following the same linear trend as the functional data. Because the VO task was not the primary task in our paradigm, we predicted increasing errors with increasing alcohol dose although previous literature (Colrain et al., 1993; Rohrbaugh et al., 1987) reports the contrary outcome. In addition, we predicted an increase in driving errors shortly after target stimulus presentation as compared to standard stimuli.
Databáze: OpenAIRE
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