Alcohol effects on inhibitory control of attention: distinguishing between intentional and automatic mechanisms

Examining the Impact of Simultaneous Alcohol and Cannabis Use on Alcohol Consumption and Consequences: Protocol for an Observational Ambulatory Assessment Study in Young Adults

BACKGROUND

There is significant conflicting evidence as to how using cannabis while drinking alcohol (ie, simultaneous alcohol and cannabis use) impacts alcohol volume consumed, patterns of drinking, and alcohol-related consequences. The impact of simultaneous use on drinking outcomes may be influenced by several within-person (eg, contextual) and between-person (individual) factors.

OBJECTIVE

This study was designed to examine naturalistic patterns of alcohol and cannabis use to understand how simultaneous use may impact drinking outcomes. The primary aims were to understand the following: (1) if simultaneous use is associated with increased alcohol consumption and riskier patterns of drinking, (2) if simultaneous use leads to increased alcohol consequences, and (3) how contextual circumstances moderate the impact of simultaneous use on consumption and consequences.

METHODS

Data collection involves a 28-day ambulatory assessment protocol in which a sample of non-treatment-seeking young adults who report simultaneous use of alcohol and cannabis complete ecological momentary assessments (random, event-contingent, and time-contingent surveys) of alcohol and cannabis use, contexts, motives, and consequences on their personal smartphones while continuously wearing an alcohol biosensor bracelet. Participants also complete a baseline assessment, brief internet-based check-in on day 14, and a final session on day 28. Community-based recruitment strategies (eg, social media and flyers) were used to enroll 95 participants to obtain a target sample of 80, accounting for attrition.

RESULTS

Recruitment and data collection began in May 2021 and continued through June 2024. Initial results for primary aims are expected in October 2024. As of March 2024, the project had recruited 118 eligible participants, of whom 94 (79.7%) completed the study, exceeding initial projections for the study time frame. Remaining recruitment will provide the capacity to probe cross-level interactions that were not initially statistically powered. Strengths of the project include rigorous data collection, good retention and compliance rates, faster-than-expected enrollment procedures, use of a novel alcohol biosensor, and successful adaptation of recruitment and data collection procedures during the COVID-19 pandemic.

CONCLUSIONS

This is the first investigation to assess the key momentary predictors and outcomes of simultaneous use as well as self-reported and objective (via alcohol biosensor) measures of alcohol consumption and patterns. The results of this study will inform prevention efforts and studies of individuals who use cannabis who are engaged in alcohol treatment.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/58685.

Assessing driving-relevant attentional impairment after a multiday drinking session: A two-phase pilot study

Background

The possibility of residual impairment of cognitive performance after multiday drinking sessions is particularly important given the potential for the deleterious effects of fatigue and hangover. This pilot study aimed to devise a methodology to compare sober performance on driving‐relevant attentional tasks at the end of a 4‐day music festival with performance at varying levels of the breath–alcohol curve.

Methods

Fifty‐two participants completed selective and sustained attention tasks at a breath alcohol concentration (BrAC) of 0.00%, 0.05%, and 0.08% following acute dosing in a controlled laboratory setting. A subset of participants (n = 13) were then tested at the conclusion of a 4‐day music festival at 0.00% BrAC, with task performance compared with laboratory results.

Results

During the laboratory phase, sustained attention was poorer at the 0.05% ascending timepoint only (compared to 0.00% BrAC). During the festival phase, participants made a greater number of errors on the selective attention task predeparture than at 0.00% and 0.05% BrAC in the laboratory. Sustained attention performance was poorer while intoxicated in the laboratory.

Conclusions

Our findings suggest that the absence of blood alcohol acutely may not be indicative of unimpaired cognitive performance and that other factors related to multiday drinking may produce driving‐related attentional deficits. The findings reinforce the need to measure attentional performance in real‐world drinking contexts despite the methodological complexities of doing so. A larger study is warranted to replicate the findings and should include attentional measures that either are more sensitive to the effects of acute alcohol intoxication than those in our study or are based on a driving simulator.

The Effects of Placebo and Moderate Dose Alcohol on Attentional Bias, Inhibitory Control and Subjective Craving

AIMS

Previous research indicates that acute alcohol intoxication and placebo can inhibit people's control over consumption behaviour and heighten attentional bias (AB) towards alcohol-related stimuli and craving. We designed a study to disentangle anticipated from pharmacological effects of alcohol in order to gain a clearer view of their relative contributions to alcohol consumption.

METHODS

In a within-participants design (moderate alcohol dose, placebo and control), and over a minimum 2-week period, participants completed a battery of questionnaires and cognitive tasks, followed by a bogus taste task to measure ad libitum consumption.

RESULTS

Both alcohol preload and placebo resulted in cognitive and psychological changes, including impaired inhibitory control, heightened AB and craving. However, ad libitum consumption only increased following alcohol and not placebo. Furthermore, inhibitory control impairments did not mediate the relationship between initial intoxication and ad libitum consumption, and findings indicate that increases in craving may mediate this association.

CONCLUSION

Psychological processes such as craving may be more important in driving consummatory behaviour relative to transient changes in cognitive processes, such as inhibitory control.

Acute alcohol does not impair attentional inhibition as measured with Stroop interference scores but impairs Stroop performance

RATIONALE

Inhibition is a core executive function and refers to the ability to deliberately suppress attention, behavior, thoughts, and/or emotions and instead act in a specific manner. While acute alcohol exposure has been shown to impair response inhibition in the stop-signal and Go/NoGo tasks, reported alcohol effects on attentional inhibition in the Stroop task are inconsistent. Notably, studies have operationalized attentional inhibition variably and there has been intra- and inter-individual variability in alcohol exposure.

OBJECTIVE

This study aimed to examine the acute effects of alcohol on attentional inhibition, considering previous limitations.

METHODS

In a single-blind, cross-over design, 40 non-dependent participants with a medium-to-high risk drinking behavior performed a Counting Stroop task (CST) under a baseline and an arterial blood alcohol concentration (aBAC) clamp at 80 mg%. Attentional inhibition was assessed as the alteration of reaction times (RT), error rates (ER), and inverse efficiency scores (IES) between incongruent and congruent trials (interference score). Stroop performance was also assessed regardless of trial-type.

RESULTS

Compared to saline, acute alcohol exposure via an aBAC clamp did not affect CST interference scores but increased RTs and IES in both incongruent and congruent trials.

CONCLUSIONS

Attentional inhibition (Stroop interference score) was not impaired by clamped moderate alcohol exposure. Acute alcohol impaired Stroop performance evidenced by a general increase in response times. Our findings suggest that response and attentional inhibition do not share the same neurocognitive mechanisms and are affected differently by alcohol. Results could also be explained by automated behaviors known to be relatively unaffected by acute alcohol.

Alcohol and the Eye

In this article, we present a review of ocular conditions related to alcohol consumption. A search of the literature published from 1952 to March 2020 was performed. The titles and abstracts were screened and the eligible studies were selected. PubMed, ISI Web of Knowledge database, Scopus, Embase, and the Cochrane Library were searched. We categorized the relationship between alcohol intake and ocular conditions by the type of ocular exposure to alcohol. Accordingly, ocular findings following acute alcohol intoxication, optic neuropathy following methanol toxicity, congenital conditions related to maternal alcohol consumption, and ocular disease related to chronic alcoholism are discussed. The main feature of alcohol intoxication in the eye is abnormal eye movement. Acute optic neuropathy secondary to methyl alcohol consumption is a serious ocular disease with permanent vision loss or scotoma. Prenatal exposure to ethanol may end in fetal alcohol spectrum disease, where ocular findings are a constant component. The association between chronic alcohol consumption and increased risks of cataract, age-related macular degeneration, diabetic retinopathy, different types of optic neuropathy, impairment of visual quality, retinal vascular disease, and ocular surface disease has also been reported. Along with detrimental medical and social effects, the role of alcohol consumption in different ocular conditions should be considered, as alcohol-induced visual disturbances may contribute to the heavy burden of alcohol abuse on the healthcare system and overall quality of life.

The effect of alcohol on food-related attentional bias, food reward and intake: Two experimental studies

Acute alcohol consumption has been shown to increase food intake, and long-term alcohol consumption may be a risk for weight gain. A potential, but under-studied, mechanism for this effect is alcohol's ability to enhance food reward. In two studies, participants consumed an alcoholic drink (Study 1: 0.3 grams of alcohol per kilogram of bodyweight (g/kg); Study 2: 0.6 g/kg) and a placebo-alcohol drink in a within-subjects design. In both studies, food-related appetitive and motivational states, and attentional bias (AB) towards food-related cues were measured. In Study 1 (N = 44), participants completed a visual probe task with concurrent recording of eye-movements which measured AB towards images of palatable foods, unpalatable foods, and non-food control items. Participants also completed measures of appetite and snack urge ratings, salivary response towards palatable foods and an ad libitum food taste test. In Study 2 (N = 84), participants completed a similar procedure, but completed a modified Stroop task which measured differences in food-related and alcohol-related AB across the two drink conditions. In Study 1, there was no difference in food-related AB between drink conditions, and no differences in snack urge, appetite ratings, salivary response, or food intake. In contrast, Study 2 showed an alcohol-induced increase in AB towards food, but not alcohol. Snack urge, alcohol urge ratings and ad libitum food intake were also higher after alcohol consumption, relative to the placebo. Collectively, these findings suggest that alcohol can increase food reward and food intake, but these effects may only occur at a higher dose.

Alcohol administration reduces attentional bias to alcohol-related but not food-related cues: Evidence for a satiety hypothesis

Attentional bias to alcohol is a well-documented effect whereby drinkers allocate greater visual attention toward alcohol-related stimuli rather than nonappetitive, neutral stimuli. Some recent research has shown that acute administration of alcohol temporarily reduces attentional bias to alcohol cues, possibly because alcohol consumption satiates the motivation to drink. However, the specificity of this effect has not been tested, and so it is unclear whether reduced attentional bias following alcohol is specific to alcohol-related stimuli or whether attention to other appetitive stimuli is also reduced (e.g., food). This study tested the degree to which acute alcohol administration selectively reduced attentional bias to alcohol-related but not to food-related cues in a group of 23 healthy young adults who reported consuming alcohol roughly twice per week. Attentional bias to alcohol-related and food-related cues was tested using visual dot probe tasks following 2 active doses of alcohol, .30 g/kg and .65 g/kg, and a placebo. Results showed that attentional bias, measured as fixation time to stimuli on the visual probe tasks, to alcohol cues declined in a dose-dependent manner, whereas attentional bias to food cues was unaffected by the doses. The evidence suggests that alcohol consumption specifically reduces attentional bias to alcohol-related stimuli whereas bias to other appetitive stimuli remains intact. Evidence that alcohol consumption reduces attentional bias specifically to alcohol cues lends further credibility to the satiation theory and to the utility of attentional bias as an indicator of acute and transient changes in an individual's motivation to use alcohol. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Ecologizing Social Psychology: The Physical Environment as a Necessary Constituent of Social Processes

Recent trends in social psychology point to increased interest in extending current theories by better incorporating the body (e.g., embodied cognition) and the broader interpersonal context (e.g., situations). However, despite being a critical component in early social theorizing, the physical environment remains in large part underdeveloped in most research programs. In this article, I outline an ecological framework for understanding the person-environment relationship. After introducing this perspective, I describe how this approach helps reveal the critical role played by the physical environment in a variety of social processes, including childhood development, interpersonal relationships, and social identity. Finally, I review a topic in environmental psychology that has received little attention among social psychologists: territories. I provide an ecological perspective on how the design, use, and personalization of this type of environment guide and constrain regulatory processes involving social behavior, identity expression, and emotional experience.

Self-Expression While Drinking Alcohol: Alcohol Influences Personality Expression During First Impressions

People are motivated to be perceived both positively and accurately and, therefore, approach social settings and adopt means that allow them to reach these goals. We investigated whether alcohol consumption helps or hinders the positivity and accuracy of social impressions using a thin-slicing paradigm to better understand the effects of alcohol in social settings and the influence of alcohol on self-expression. These possibilities were tested in a sample of 720 participants randomly assigned to consume an alcohol, placebo, or control beverage while engaged in conversation in three-person groups. We found support for the hypothesis that alcohol (compared with placebo or control) increased the positivity of observers' personality expression, but did not find support for the hypothesis that alcohol increased the accuracy of personality expression. These findings contribute to our understanding of the social consequences of alcohol consumption, shedding new light on the interpersonal benefits that alcohol can foster.

To look or not to look? Reward, selection history, and oculomotor guidance

The current eye-tracking study examined the influence of reward on oculomotor performance, and the extent to which learned stimulus-reward associations interacted with voluntary oculomotor control with a modified paradigm based on the classical antisaccade task. Participants were shown two equally salient stimuli simultaneously: a gray and a colored circle, and they were instructed to make a fast saccade to one of them. During the first phase of the experiment, participants made a fast saccade toward the colored stimulus, and their performance determined a (cash) bonus. During the second, participants made a saccade toward the gray stimulus, with no rewards available. On each trial, one of three colors was presented, each associated with high, low or no reward during the first phase. Results from the first phase showed improved accuracy and shorter saccade latencies on high-reward trials, while those from the second replicated well-known effects typical of the antisaccade task, namely, decreased accuracy and increased latency during phase II, even despite the absence of abrupt asymmetric onsets. Crucially, performance differences between phases revealed longer latencies and less accurate saccades during the second phase for high-reward trials, compared with the low- and no-reward trials. Further analyses indicated that oculomotor capture by reward signals is mainly found for saccades with short latencies, while this automatic capture can be overridden through voluntary control with longer ones. These results highlight the natural flexibility and adaptability of the attentional system, and the role of reward in modulating this plasticity. NEW & NOTEWORTHY Typically, in the antisaccade task, participants need to suppress an automatic orienting reflex toward a suddenly appearing peripheral stimulus. Here, we introduce an alternative antisaccade task without such abrupt onsets. We replicate well-known antisaccade effects (more errors and longer latencies), demonstrating the role of reward in developing selective oculomotor biases. Results highlight how reward and selection history facilitate developing automatic biases from goal-driven behavior, and they suggest that this process responds to individual differences in impulsivity.

The effect of beliefs about alcohol's acute effects on alcohol priming and alcohol-induced impairments of inhibitory control

Acute alcohol administration can lead to a loss of control over drinking. Several models argue that this 'alcohol priming effect' is mediated by the effect of alcohol on inhibitory control. Alternatively, beliefs about how alcohol affects behavioural regulation may also underlie alcohol priming and alcohol-induced inhibitory impairments. Here two studies examine the extent to which the alcohol priming effect and inhibitory impairments are moderated by beliefs regarding the effects of alcohol on the ability to control behaviour. In study 1, following a priming drink (placebo or .5g/kg of alcohol), participants were provided with bogus feedback regarding their performance on a measure of inhibitory control (stop-signal task; SST) suggesting that they had high or average self-control. However, the bogus feedback manipulation was not successful. In study 2, before a SST, participants were exposed to a neutral or experimental message suggesting acute doses of alcohol reduce the urge to drink and consumed a priming drink and this manipulation was successful. In both studies craving was assessed throughout and a bogus taste test which measured ad libitum drinking was completed. Results suggest no effect of beliefs on craving or ad lib consumption within either study. However, within study 2, participants exposed to the experimental message displayed evidence of alcohol-induced impairments of inhibitory control, while those exposed to the neutral message did not. These findings do not suggest beliefs about the effects of alcohol moderate the alcohol priming effect but do suggest beliefs may, in part, underlie the effect of alcohol on inhibitory control.

Alcohol effects on response inhibition: Variability across tasks and individuals

Considerable research has investigated the acute effects of alcohol on response inhibition, but a number of issues remain unresolved. Given that most studies use only a single laboratory task to assess inhibition, it is often difficult to determine whether alcohol's effects are task specific or generalize across measures of the same construct. Moreover, relatively few studies have directly compared effects of alcohol under ascending and descending blood alcohol concentrations (BACs), and those that have often failed to disentangle BAC limb effects from the effects of repeated testing. This study was intended to provide a test of alcohol's effects on behavioral inhibition using multiple laboratory measures in a relatively large sample and comparing effects under ascending and descending BAC. Young adults (N = 216) completed three commonly used inhibition tasks (Stroop, antisaccade, and stop-signal) at baseline and again 1-3 weeks later under one of three beverage conditions (alcohol, placebo or control) and one of two BAC limb conditions (ascending/descending or descending only). Findings indicated considerable specificity in alcohol's effects. Relative to control and placebo conditions, antisaccade performance suffered under both ascending and descending BAC and stop-signal reaction time (RT) suffered only under descending BAC. The Stroop RT interference effect was not affected by alcohol, though alcohol did impair response accuracy on incongruent Stroop trials. Baseline performance moderated effects of alcohol on both antisaccade accuracy and Stroop interference, suggesting the importance of individual differences. The current findings suggest that more specificity is required in characterizing acute effects of alcohol on inhibitory control. (PsycINFO Database Record

Ethanol-induced autonomic responses and risk taking increase in young adults with a positive family history of alcohol problems

The mechanisms that underlie the greater prevalence of alcohol use disorders in individuals with a positive family history (FH+) of alcohol abuse are still under investigation. These subjects may exhibit differential sensitivity to alcohol's effects on psychomotor stimulation and impulsivity. Alcohol-induced psychomotor stimulation, measured as the heart rate (HR) response, is a proxy for the positive rewarding effects of the drug. We analyzed alcohol-induced effects on time perception (Time Production Task), risk taking (Balloon Analogue Risk Task [BART]), and HR in FH+ and FH- participants. In the FH+ and FH- groups, women and men received 0.6 and 0.7g/kg alcohol, respectively. The alcohol dose yielded a breath alcohol concentration of 0.08% throughout the experiment. The control groups received placebo, and the subjective perception of alcohol intoxication was assessed. Alcohol intoxication significantly increased HR and the adjusted average number of pumps on the BART (a measure of risk taking) in FH+ men and women but not in FH- participants. Behavioral impulsivity was unaffected by alcohol or a FH of alcohol abuse. FH- but not FH+ participants who received alcohol reported significantly greater subjective perception of alcohol's effects than their placebo counterparts. These results indicate that FH+ individuals presented heightened sensitivity to alcohol-induced HR stimulation and alcohol-induced risk taking compared with their FH- counterparts. FH+ subjects, however, were insensitive to the subjective effects of alcohol. This idiosyncratic response pattern may be a likely pathway by which a FH of alcohol problems promotes alcohol drinking.

Impairment of manual but not saccadic response inhibition following acute alcohol intoxication

BACKGROUND

Alcohol impairs response inhibition; however, it remains contested whether such impairments affect a general inhibition system, or whether affected inhibition systems are embedded in, and specific to, each response modality. Further, alcohol-induced impairments have not been disambiguated between proactive and reactive inhibition mechanisms, and nor have the contributions of action-updating impairments to behavioural 'inhibition' deficits been investigated.

METHODS

Forty Participants (25 female) completed both a manual and a saccadic stop-signal reaction time (SSRT) task before and after a 0.8g/kg dose of alcohol and, on a separate day, before and after a placebo. Blocks in which participants were required to ignore the signal to stop or make an additional 'dual' response were included to obtain measures of proactive inhibition as well as updating of attention and action.

RESULTS

Alcohol increased manual but not saccadic SSRT. Proactive inhibition was weakly reduced by alcohol, but increases in the reaction times used to baseline this contrast prevent clear conclusions regarding response caution. Finally, alcohol also increased secondary dual response times of the dual task uniformly as a function of the delay between tasks, indicating an effect of alcohol on action-updating or execution.

CONCLUSIONS

The modality-specific effects of alcohol favour the theory that response inhibition systems are embedded within response modalities, rather than there existing a general inhibition system. Concerning alcohol, saccadic control appears relatively more immune to disruption than manual control, even though alcohol affects saccadic latency and velocity. Within the manual domain, alcohol affects multiple types of action updating, not just inhibition.

Effects of acute alcohol ingestion on eye movements and cognition: A double-blind, placebo-controlled study

Alcohol is one of the most consumed psychoactive substances in the world, and the negative impact related to alcohol use has become a worldwide public health issue. Alcohol is able to affect diffusely several areas of the Central Nervous System, which could impair visual functions, including eye movements, and cognitive processes. The objective of the present study was to investigate the effects of moderate alcohol intake in eyes movements, as an indicator of cognitive processing underlying the visual search in a the Maze task. We investigated the concentration of 0.08% blood alcohol concentration (BAC), using an intra-subject, double-blind, and placebo-controlled experimental design with a sample size of 20 young adults (11 men and nine women). All volunteers participated in both conditions, i.e., alcohol (0.08%) and placebo (0.00%), in a counterbalanced order. We use the Tobii TX300 eye tracker to evaluate eye movements during completion of Visual Maze Test. The results showed significant differences in the following eye movement patterns: the first fixation latency, number and duration of fixations (mean and total), the number and duration of saccades (mean and total), and the total execution time in the test. In addition, we investigate the areas of interest (AOI), decision points in which the participant must decide which course to follow. We verified that the participants in the alcohol condition had a significantly greater number of fixations in both AOI, in comparison to the placebo condition. Overall, our findings confirm that moderate doses of alcohol can change the eye movements of young adults. These alterations may evidence the influence of alcohol in cognitive processes, such as flexibility, attention, and planning, which are required during resolution of Maze Task.

A simulation study of the effects of alcohol on driving performance in a Chinese population

Driving under the influence of alcohol (DUIA) is a significant factor contributing to road traffic crashes, injuries, and fatalities. Although the effects of alcohol on driving performance are widely acknowledged, studies of the effects of alcohol impairment on driving performance and particularly on the control system of Chinese adults are rare. This study attempts to evaluate the effects of alcohol on the driving performance of Chinese adults using a driving simulator.

METHOD

A double-blind experimental study was conducted to evaluate the effects of alcohol impairment on the driving performance of 52 Chinese participants using a driving simulator. A series of simulated driving tests covering two driving modules, including emergency braking (EB) and following braking (FB), at 50km/h and 80km/h were performed. Linear mixed models were established to evaluate driving performance in terms of braking reaction time (BRT), the standard deviation of lateral position (SD-LANE), and the standard deviation of speed (SD-SPEED).

RESULTS

Driving performance in terms of BRT and SD-LANE was highly correlated with the level of alcohol consumption, with a one-unit increase in breath alcohol concentration (BrAC) degrading BRT and SD-LANE by 0.3% and 0.2%, respectively. Frequent drinkers generally reacted faster in their BRT than less-frequent drinkers and non-drinkers by 10.2% and 30.6%, respectively. Moreover, alcohol impairment had varying effects on certain aspects of the human control system, and automatic action was less likely to be affected than voluntary action from a psychological viewpoint.

CONCLUSION

The findings should be useful for planning and developing effective measures to combat drink driving in Chinese communities.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity.

Multisensory Stop Signals Can Reduce the Disinhibiting Effects of Alcohol in Adults

BACKGROUND

Alcohol impairs drinkers' abilities to inhibit inappropriate responses. Certain stimulus conditions have been shown to facilitate behavioral control. Under conditions where individuals are presented with multiple inhibitory signals, the speed and consistency with which they are able to inhibit a response is improved. Recent research has shown that multisensory signals might protect against the disruptive effects of alcohol on mechanisms of behavioral control. This study examined whether multisensory stop signals can be used to improve inhibitory control, possibly by speeding attentional shifts toward inhibitory "stop" signals in the environment.

METHODS

Twenty adult social drinkers performed a modified cued go/no-go task that measured the ability to inhibit prepotent responses following 0.64 g/kg alcohol and placebo. Response targets were presented as unimodal (visual) and as multisensory (visual + aural) stimuli.

RESULTS

Results showed that during unimodal response target trials, participants made more inhibitory failures under 0.64 g/kg alcohol compared to placebo. During multisensory trials, however, there was no significant effect of alcohol on inhibitory control.

CONCLUSIONS

These findings identify multisensory inhibitory signals as a potentially important environmental factor that can reduce the degree to which alcohol disinhibits behavior possibly by intersensory co-activation between the visual and auditory pathways.

Effects of alcohol intake on time-based event expectations

Previous evidence suggests that alcohol affects various forms of temporal cognition. However, there are presently no studies investigating whether and how alcohol affects on time-based event expectations. Here, we investigated the effects of alcohol on time-based event expectations. Seventeen healthy volunteers, aged between 19 and 36 years, participated. We employed a variable foreperiod paradigm with temporally predictable events, mimicking a computer game. Error rate and reaction time were analyzed in placebo (0 g/kg), low dose (0.2 g/kg) and high dose (0.6 g/kg) conditions. We found that alcohol intake did not eliminate, but substantially reduced, the formation of time-based expectancy. This effect was stronger for high doses, than for low doses, of alcohol. As a result of our studies, we have evidence that alcohol intake impairs time-based event expectations. The mechanism by which the level of alcohol impairs time-based event expectations needs to be clarified by future research.

Disruption of sensory gating by moderate alcohol doses

RATIONALE

Evidence from a growing body of literature suggests that alcohol, even at moderate-dose levels, disrupts the ability to ignore distractors. However, little work has been done to elucidate the neural processes underlying this deficit.

OBJECTIVE

The present study was conducted to determine if low-to-moderate alcohol doses affect sensory gating, an electrophysiological phenomenon believed to reflect the pre-attentive filtering of irrelevant sensory information.

METHODS

Sixty social drinkers were administered one of three doses intended to produce breath alcohol concentrations of 0.0% (placebo), 0.04% (i.e., low dose), and 0.065% (i.e., moderate dose). A paired-click paradigm consisting of 100 pairs of identical tones (S1 and S2) was used to assess sensory gating. Amplitudes of P50, N100, and P200 auditory evoked potentials (AEPs) were used to calculate gating difference (S1-S2) and ratio (S2/S1) scores.

RESULTS

The moderate alcohol dose significantly decreased P50 and N100 gating relative to placebo. Comparisons between the difference and ratio scores helped characterize the gating mechanisms affected at these stages of information processing. Alcohol did not alter P200 sensory gating.

CONCLUSIONS

These data suggest that alcohol disrupts pre-attentional sensory-filtering processes at breath alcohol concentrations (BrACs) below the current 0.08% legal limit. Future studies should perform a combined assessment of sensory gating and selective attention to better understand the relationship between these two alcohol-induced deficits.

Oculomotor inhibitory control in express saccade makers

Express saccade makers (ESMs) produce high proportions (>30 %) of low-latency (80-130 ms) express saccades in tasks in which such responses are usually suppressed. In addition, high directional error rates on the antisaccade (AS) task suggest a failure of oculomotor inhibitory mechanisms in ESMs. However, the AS task is complex and does not provide a measure of inhibitory processes in isolation. We therefore examined inhibitory control in 25 ESM and 28 non-ESM ('Norm') participants, using a minimally delayed oculomotor response (MDOR) task. After a randomised fixation period, a pro-saccade target appeared for 200 or 1,000 ms. Participants were instructed to maintain fixation and saccade to the target position upon target offset. In a control task, they saccaded on target onset. Overall, saccade latency was considerably increased in the MDOR task compared to the control task (354 vs. 170 ms; p < 0.001), and we also observed a latency modulation with display time (200: 399, 1,000: 302 ms; p < 0.001). However, there was no evidence of a difference between groups (p = 0.29). Errors consisted primarily of responses to target onsets and error rates were comparable between the groups (p = 0.33). The overproduction of fast, reflexive responses was still observed in ESMs who generated a higher proportion of their errors within the express latency range (p < 0.001). We confirmed that in the AS task, the ESMs exhibited a higher directional error rate (p = 0.03). These results suggest that the performance 'deficit' observed on the AS task in ESMs cannot be attributed to generally weaker inhibitory control.

Heavy drinking and the role of inhibitory control of attention

Alcohol can disrupt goal-directed behavior by impairing the ability to inhibit attentional shifts toward salient but goal-irrelevant stimuli. Individuals who are highly sensitive to this effect of the drug may be at increased risk for problematic drinking, especially among those whose attention is drawn to alcohol-related cues in the environment (i.e., attentional bias). The current study examined the acute impairing effect of alcohol on inhibitory mechanisms of attentional control in a group of healthy social drinkers. We then examined whether increased sensitivity to this disinhibiting effect of alcohol was associated with heavy drinking, especially among those who have an attentional bias toward alcohol-related stimuli. Eighty nondependent social drinkers performed a delayed ocular response task that measured their inhibitory control of attention by their ability to suppress attentional shifts to irrelevant stimuli. Attentional bias was measured using a visual probe task. Inhibitory control was assessed following a moderate dose of alcohol (0.64 g/kg) and a placebo. Participants made more inhibitory failures (i.e., premature saccades) following 0.64 g/kg alcohol compared with placebo and the relation of this effect to their drinking habits did depend on the level of the drinker's attentional bias to alcohol-related stimuli. Among drinkers with higher attentional bias, greater impairment of inhibitory control was associated with heavier drinking. In contrast, drinkers with little or no attentional bias showed no relation between their sensitivity to the disinhibiting effects of alcohol and drinking habits. These findings have implications for understanding how heightened incentive-salience of alcohol cues and impaired attentional control can interactively contribute to excessive alcohol use.

Alcohol disrupts the effects of priming on the perception of ambiguous figures

Inhibitory mechanisms are thought to underpin the well-documented impairing effects of alcohol on attention. Here, we use a novel priming paradigm to investigate the effects of alcohol on inhibitory mechanisms in attention. Participants were assigned to an alcohol (N=15), or placebo (N=15) group. The dose of alcohol was 0.8 g/kg for males and 0.75 g/kg for females. Participants were asked to report figure reversals during presentation of the face-vase ambiguous figure. Prior to this, they were shown a prime that was either semantically relevant to the face-vase stimulus or was neutral. Semantic priming decreased the number of figure reversals in the first half of the test session in the placebo group but not in the alcohol group. The placebo group was also more likely than the alcohol group to report the first interpretation of the figure to be the same as the semantic prime. Prior presentation of a semantic prime had a stabilising effect on reversal rate, suggesting that the primed interpretation inhibited the alternate interpretation. The absence of an effect in the alcohol group is consistent with an alcohol-related impairment of this inhibition.

Alcohol reduces cross-frequency theta-phase gamma-amplitude coupling in resting electroencephalography

BACKGROUND

The electrophysiological inhibitory mechanism of cognitive control for alcohol remains largely unknown. The purpose of the study was to compare electroencephalogram (EEG) power spectra and cross-frequency phase-amplitude coupling (CFPAC) at rest and during a simple subtraction task after acute alcohol ingestion.

METHODS

Twenty-one healthy subjects participated in this study. Two experiments were performed 1 week apart, and the order of the experiments was randomly assigned to each subject. During the experiments, each subject was provided with orange juice containing alcohol or orange juice only. We recorded EEG activity and analyzed power spectra and CFPAC data.

RESULTS

The results showed prominent theta-phase gamma-amplitude coupling at the frontal and parietal electrodes at rest. This effect was significantly reduced after alcohol ingestion.

CONCLUSIONS

Our findings suggest that theta-phase gamma-amplitude coupling is deficiently synchronized at rest after alcohol ingestion. Therefore, cross-frequency coupling could be a useful tool for studying the effects of alcohol on the brain and investigating alcohol addiction.

Effects of alcohol on attentional mechanisms involved in figure reversals

OBJECTIVE

The impairing effects of alcohol on attention are well documented and are thought to involve inhibitory mechanisms. We used ambiguous figures (Face-Vase and Necker cube) to test whether the intentional control mechanism is more vulnerable to the effects of alcohol than the automatic mechanism.

METHOD

Participants were assigned to an alcohol (Study 1, N = 15; Study 2, N = 18), placebo (Study 1, N = 15; Study 2, N = 20) or control (Study 1 only, N = 10) group. The doses of alcohol were 0.8 g/kg for men and 0.75 g/kg for women. Participants were shown the Face-Vase and Necker cube figures and two variants of each, which were biased in varying degrees towards one interpretation. Study 1 assessed the automatic control mechanism by asking participants to report spontaneous reversals. Study 2 assessed the intentional control mechanism by asking participants to increase reversal rate.

RESULTS

In Study 1, reversal rate was similar for all groups, whereas in Study 2, the alcohol group reported more reversals than the control group, although this was true only for the biased versions of the Face-Vase illusion.

CONCLUSIONS

The effect of alcohol on reversal rate is observed only during intentional reversals of semantically meaningful stimuli and only when the stimulus is biased.

Acute alcohol consumption impairs controlled but not automatic processes in a psychophysical pointing paradigm

Numerous studies have investigated the effects of alcohol consumption on controlled and automatic cognitive processes. Such studies have shown that alcohol impairs performance on tasks requiring conscious, intentional control, while leaving automatic performance relatively intact. Here, we sought to extend these findings to aspects of visuomotor control by investigating the effects of alcohol in a visuomotor pointing paradigm that allowed us to separate the influence of controlled and automatic processes. Six male participants were assigned to an experimental "correction" condition in which they were instructed to point at a visual target as quickly and accurately as possible. On a small percentage of trials, the target "jumped" to a new location. On these trials, the participants' task was to amend their movement such that they pointed to the new target location. A second group of 6 participants were assigned to a "countermanding" condition, in which they were instructed to terminate their movements upon detection of target "jumps". In both the correction and countermanding conditions, participants served as their own controls, taking part in alcohol and no-alcohol conditions on separate days. Alcohol had no effect on participants' ability to correct movements "in flight", but impaired the ability to withhold such automatic corrections. Our data support the notion that alcohol selectively impairs controlled processes in the visuomotor domain.

Separating intentional inhibition of prepotent responses and resistance to proactive interference in alcohol-dependent individuals

BACKGROUND

Impulsivity is a hallmark of addictive behaviors. Addicts' weakened inhibition of irrelevant prepotent responses is commonly thought to explain this association. However, inhibition is not a unitary mechanism. This study investigated the efficiency of overcoming competition due to irrelevant responses (i.e., inhibition of a prepotent response) and overcoming competition in memory (i.e., resistance to proactive interference) in sober and recently detoxified alcohol-dependent individuals.

METHODS

Three cognitive tasks assessing the inhibition of a prepotent response (Hayling task, anti-saccade task and Stroop task) and two tasks tapping into the capacity to resist proactive interference (cued recall, Brown-Peterson variant) were administered to 30 non-amnesic recently detoxified alcohol-dependent individuals and 30 matched healthy participants without alcohol dependency. In addition, possible confounds such as verbal updating in working memory was assessed.

RESULTS

Alcohol-dependent subjects performed worse than healthy participants on the three cognitive tasks assessing the inhibition of irrelevant prepotent responses but group performance was similar in the tasks assessing overcoming proactive interference in memory, updating of working memory and abstract reasoning.

CONCLUSIONS

These findings suggest that alcohol-dependence is mainly associated with impaired capacity to intentionally suppress irrelevant prepotent response information. Control of proactive interference from memory is preserved. Theoretical and clinical implications are discussed.

Dose-related effects of alcohol on cognitive functioning

We assessed the suitability of six applied tests of cognitive functioning to provide a single marker for dose-related alcohol intoxication. Numerous studies have demonstrated that alcohol has a deleterious effect on specific areas of cognitive processing but few have compared the effects of alcohol across a wide range of different cognitive processes. Adult participants (N = 56, 32 males, 24 females aged 18–45 years) were randomized to control or alcohol treatments within a mixed design experiment involving multiple-dosages at approximately one hour intervals (attained mean blood alcohol concentrations (BACs) of 0.00, 0.048, 0.082 and 0.10%), employing a battery of six psychometric tests; the Useful Field of View test (UFOV; processing speed together with directed attention); the Self-Ordered Pointing Task (SOPT; working memory); Inspection Time (IT; speed of processing independent from motor responding); the Traveling Salesperson Problem (TSP; strategic optimization); the Sustained Attention to Response Task (SART; vigilance, response inhibition and psychomotor function); and the Trail-Making Test (TMT; cognitive flexibility and psychomotor function). Results demonstrated that impairment is not uniform across different domains of cognitive processing and that both the size of the alcohol effect and the magnitude of effect change across different dose levels are quantitatively different for different cognitive processes. Only IT met the criteria for a marker for wide-spread application: reliable dose-related decline in a basic process as a function of rising BAC level and easy to use non-invasive task properties.

Comparison of alcohol impairment of behavioral and attentional inhibition

BACKGROUND

Despite the wealth of studies demonstrating the impairing effects of alcohol on behavioral inhibition, less is known regarding effects of the drug on attentional inhibition (i.e., the ability to ignore distracting stimuli in the environment in order to focus attention on relevant information). The current study examined alcohol impairment of both behavioral and attentional inhibition, as well as potential associations between the two mechanisms of inhibitory control.

METHODS

Men (n=27) and women (n=21) performed a measure of behavioral inhibition (cued go/no-go task) and a measure of attentional inhibition (delayed ocular return task) following three doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo).

RESULTS

Alcohol impaired both behavioral and attentional inhibition relative to placebo; however, correlational analyses revealed no associations between measures of behavioral and attentional inhibition following any dose. Additionally, men committed more inhibitory failures on the behavioral inhibition task, whereas women committed more inhibitory failures on the attentional inhibition task.

CONCLUSIONS

These findings suggest that behavioral and attentional inhibition are equally sensitive to the impairing effects of alcohol, yet represent distinct components of inhibitory control. Additionally, the observed gender differences in control of behavior and attention could have important implications regarding negative consequences associated with alcohol-induced disinhibition in men and women.

On the measurement of the effects of alcohol and illicit substances on inhibition of return

RATIONALE

Inhibition of return (IOR) refers to the delayed orienting of attention to previously inspected locations in favour of novel locations. Given its implications for visual attention and search, researchers have begun to investigate whether IOR may be impaired by the use of alcohol or illicit substances (e.g. d-amphetamine).

OBJECTIVES

The present paper reviews the existing literature exploring the impact of alcohol and other drugs on IOR through the use of the model spatial cueing task developed by Posner.

RESULTS

Studies were located that investigated IOR paradigm with respect to either (a) acute effects of alcohol or other psychoactive substances and (b) hallucinogenic drug states as models for psychosis. Findings suggest that alcohol, d-amphetamine and some hallucinogens may alter the timecourse of IOR. This review also yields a critical qualitative analysis of the methodology of studies in this field of research and the implications of particular methodological features for interpreting previous findings.

CONCLUSIONS

The importance of using multiple stimulus onset asynchronies, employing a cue-back to centre paradigm and distinguishing between acute and chronic substance use are emphasized. Furthermore, questions are raised as to whether findings suggest an impact of psychoactive substances on the subcortical mechanisms that play a critical role in the generation of IOR or are an indirect effect resulting from impairment of the cortical mechanisms responsible for voluntary disengagement of attention. Directions for future research and particular methodological approaches are highlighted.

Impaired control over alcohol use: An under-addressed risk factor for problem drinking in young adults?

Impaired control over alcohol use may be defined as "a breakdown of an intention to limit consumption in a particular situation" (Heather, Tebbutt, Mattick, & Zamir, 1993, p. 701) and has long been considered an important feature of alcohol dependence. Evidence suggests impaired control is highly relevant to young adult problem drinking. In the natural history of problem drinking, impaired control tends to develop early and may predict alcohol-related problems prospectively in undergraduates. Impaired control over alcohol use may be a facet of generalized behavioral undercontrol specifically related to drinking. In particular, impaired control is theoretically and empirically related to impulsivity. The question of whether impaired control represents a facet of impulsivity or a related but separate construct requires further study. However, theoretical arguments and empirical evidence suggest that there are unique qualities to the constructs. Specifically, existing data suggest that self-report measures of impaired control and impulsivity over alcohol use relate distinctly to problem drinking indices in young adults. Several lines of future research concerning impaired control are suggested, using the impulsivity literature as a guide. We conclude that impaired control is a valuable construct to the study of young adult problem drinking and that measures of impaired control should be included in more young adult alcohol studies. The extent to which impaired control over the use of other substances and impaired control over engagement in other addictive behaviors are clinically relevant constructs requires additional study.

Blood alcohol concentration at 0.06 and 0.10% causes a complex multifaceted deterioration of body movement control

Alcohol-related falls are recognized as a major contributor to the occurrence of traumatic brain injury. The control of upright standing balance is complex and composes of contributions from several partly independent mechanisms such as appropriate information from multiple sensory systems and correct feedback and feed forward movement control. Analysis of multisegmented body movement offers a rarely used option for detecting the fine motor problems associated with alcohol intoxication. The study aims were to investigate whether (1) alcohol intoxication at 0.06 and 0.10% blood alcohol concentration (BAC) affected the body movements under unperturbed and perturbed standing; and (2) alcohol affected the ability for sensorimotor adaptation. Body movements were recorded in 25 participants (13 women and 12 men, mean age 25.1 years) at five locations (ankle, knee, hip, shoulder, and head) during quiet standing and during balance perturbations from pseudorandom pulses of calf muscle vibration over 200s with eyes closed or open. Tests were performed at 0.00, 0.06, and 0.10% BAC. The study revealed several significant findings: (1) an alcohol dose-specific effect; (2) a direction-specific stability decrease from alcohol intoxication; (3) a movement pattern change related to the level of alcohol intoxication during unperturbed standing and perturbed standing; (4) a sensorimotor adaptation deterioration with increased alcohol intoxication; and (5) that vision provided a weaker contribution to postural control during alcohol intoxication. Hence, alcohol intoxication at 0.06 and 0.10% BAC causes a complex multifaceted deterioration of human postural control.

Effects of acute alcohol intoxication on automated processing: evidence from the double-step paradigm

Reflexive and voluntary levels of processing have been studied extensively with respect to possible impairments due to alcohol intoxication. This study examined alcohol effects at the 'automated' level of processing essential to many complex visual processing tasks (e.g., reading, visual search) that involve ongoing modifications or reprogramming of well-practiced routines. Data from 30 participants (16 male) were collected in two counterbalanced sessions (alcohol vs. no-alcohol control; mean breath alcohol concentration = 68 mg/dL vs. 0 mg/dL). Eye movements were recorded during a double-step task where 75% of trials involved two target stimuli in rapid succession (inter-stimulus interval [ISI]=40, 70, or 100 ms) so that they could elicit two distinct saccades or eye movements (double steps). On 25% of trials a single target appeared. Results indicated that saccade latencies were longer under alcohol. In addition, the proportion of single-step responses and the mean saccade amplitude (length) of primary saccades decreased significantly with increasing ISI. The key novel finding, however, was that the reprogramming time needed to cancel the first saccade and adjust saccade amplitude was extended significantly by alcohol. The additional time made available by prolonged latencies due to alcohol was not utilized by the saccade programming system to decrease the number of two-step responses. These results represent the first demonstration of specific alcohol-induced programming deficits at the automated level of oculomotor processing.

Correlates of alcohol use in adults with ADHD and comorbid alcohol use disorders: exploratory analysis of a placebo-controlled trial of atomoxetine

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and substance use disorder are often comorbid in adults. The effects of ADHD treatment on comorbid alcohol use disorder have not been extensively studied.

OBJECTIVE

To assess correlates of ADHD and alcohol use outcomes in ADHD with comorbid alcohol use disorders, via a post-hoc exploratory subgroup analysis of a previously conducted, randomized, double-blind, placebo-controlled study of recently abstinent adults.

METHODS

Adults who had ADHD and alcohol use disorders and were abstinent for 4-30 days were randomized to daily atomoxetine 25-100 mg (mean final dose = 89.9 mg) or placebo for 12 weeks. Changes in ADHD symptoms from baseline to endpoint were assessed using the ADHD Investigator Symptom Rating Scale (AISRS) total score, alcohol use by the timeline followback method, and alcohol cravings by the Obsessive Compulsive Drinking Scale.

RESULTS

Of 147 subjects receiving atomoxetine (n = 72) or placebo (n = 75) in the primary study, 80 (54%) completed 12 weeks (n = 32 atomoxetine; n = 48 placebo). Improvements in ADHD symptoms on the AISRS correlated significantly with decreases in alcohol cravings (Pearson's r = 0.28; 95% confidence interval [CI] = 0.11-0.43; p = 0.002), and the correlation was most notable with atomoxetine (r = 0.29; CI [0.04 - 0.51]; p = 0.023) rather than with placebo (r = 0.24; CI [0.00-0.46]; p = 0.055). On-treatment drinking levels correlated with AISRS scores (r = 0.12; CI [0.05 -0.19]; p = 0.001). Relapse to alcohol abuse significantly correlated with worse ADHD symptoms on 15 of 18 items of the AISRS in the placebo group (p < 0.05 for each).

CONCLUSIONS

No baseline predictor (other than degree of sobriety) of alcohol use or ADHD outcomes emerged. ADHD symptom improvements correlated significantly with reductions in alcohol cravings, and relapse to alcohol abuse correlated significantly with worsening of most ADHD symptoms in the placebo group, but not in the atomoxetine group. This post-hoc subgroup analysis is of a hypothesis-generating nature, and the generalizability of the findings may be limited by exclusion of adults with common ADHD comorbidities from the base study. Further, prospective clinical trials in larger and more heterogeneous patient populations are warranted to confirm or reject these preliminary associations. TRIAL REGISTRATION (BASE STUDY): ClinicalTrials.gov identifier: NCT00190957.

Does response variability predict distractibility among adults with attention-deficit/hyperactivity disorder?

Increased intraindividual variability in response time (RTSD) has been observed reliably in attention-deficit/hyperactivity disorder (ADHD) and has often been used as a measure of inattention. RTSD is assumed to reflect attentional lapses and distractibility, though evidence for the validity of this connection is lacking. We assessed whether RTSD is an indicator of inattention by comparing RTSD on the stop-signal task (SST) with performance on the delayed oculomotor response (DOR) task, a measure of distractibility. Participants included 30 adults with ADHD and 28 controls. Participants completed the SST and the DOR task, which measured subjects' ability to maintain attention and avoid distraction by inhibiting reflexive saccades toward distractors. On the SST, the ADHD group was slower to inhibit than were controls, indicating poorer inhibitory control in ADHD. The ADHD group also displayed slower reaction times (RTs), greater RTSD, and more omission errors. On the DOR task, the ADHD group displayed more premature saccades (i.e., greater distractibility) than did controls. Greater variability in RT was associated with increased distraction on the DOR task, but only in ADHD participants. Results suggest that RTSD is linked to distractibility among adults with ADHD and support the use of RTSD as a valid measure of inattention in ADHD.

Persistence of attentional bias toward alcohol-related stimuli in intoxicated social drinkers

BACKGROUND

Although attentional bias to alcohol-related stimuli has been identified as a potentially important factor in initiating a drinking episode, little is known about whether it persists once drinking has begun. Chief among the measures of attentional bias is the visual probe task, which requires the ability to respond quickly and fixate on objects. Alcohol is well recognized for impairing both of these abilities, which could undermine the reliable detection of attentional bias in intoxicated individuals. The purpose of the present study was to determine if attentional bias toward alcohol-related images can still be observed under alcohol even at blood alcohol concentrations (BACs) sufficient to disrupt reaction time (RT) and basic ocular functions.

METHODS

The present study employed a within-subject design to test the effects of three doses of alcohol (0.0 g/kg, 0.32 g/kg, and 0.64 g/kg) on attentional bias toward alcohol-related images in a group of 20 social drinkers using a visual probe task. Alcohol's effects on simple RT and ocular functions were also assessed.

RESULTS

Attentional bias was observed by participants' fixations toward alcohol-related stimuli following alcohol administration. Alcohol also impaired oculomotor functions as evident by decreased accuracy and speed of saccades.

DISCUSSION

The findings indicate that attentional bias can be detected even at BACs above 80 mg/100 ml that disrupt oculomotor functions that are considered fundamental to visual search tasks.

Separating automatic and intentional inhibitory mechanisms of attention in adults with attention-deficit/hyperactivity disorder

Researchers in the cognitive sciences recognize a fundamental distinction between automatic and intentional mechanisms of inhibitory control. The use of eye-tracking tasks to assess selective attention has led to a better understanding of this distinction in specific populations, such as children with attention-deficit/hyperactivity disorder (ADHD). This study examined automatic and intentional inhibitory control mechanisms in adults with ADHD using a saccadic interference task and a delayed ocular response task. Thirty adults with ADHD were evaluated against 27 comparison adults on measures of inhibitory control. The delayed ocular response task showed that adults with ADHD were less able than comparison adults to inhibit a reflexive saccade toward the sudden appearance of a stimulus in the periphery. However, saccadic interference task performance showed that the ADHD group did not differ significantly from the comparison group on a measure of automatic inhibitory control. These findings suggest a dissociation between automatic and intentional inhibitory deficits in adults with ADHD.

Functional biomarkers for the acute effects of alcohol on the central nervous system in healthy volunteers

The central nervous system (CNS) effects of acute alcohol administration have been frequently assessed. Such studies often use a wide range of methods to study each of these effects. Unfortunately, the sensitivity of these tests has not completely been ascertained. A literature search was performed to recognize the most useful tests (or biomarkers) for identifying the acute CNS effects of alcohol in healthy volunteers. All tests were grouped in clusters and functional domains. Afterwards, the effect of alcohol administration on these tests was scored as improvement, impairment or as no effect. Furthermore, dose-response relationships were established. A total number of 218 studies, describing 342 different tests (or test variants) were evaluated. Alcohol affected a wide range of CNS domains. Divided attention, focused attention, visuo-motor control and scales of feeling high and of subjective drug effects were identified as the most sensitive functional biomarkers for the acute CNS effects of alcohol. The large number of CNS tests that are used to determine the effects of alcohol interferes with the identification of the most sensitive ones and of drug-response relationships. Our results may be helpful in selecting rational biomarkers for studies investigating the acute CNS effects of alcohol or for future alcohol- interaction studies.

Behavioral components of impulsivity predict alcohol consumption in adults with ADHD and healthy controls

BACKGROUND

The degree to which distinct behavioral components of impulsivity predict alcohol consumption is as yet not well-understood. Further, the possibility that this relation might be more pronounced in groups characterized by heightened impulsivity (i.e., individuals with ADHD) has not been tested.

METHODS

The current study examined the degree to which three specific behavioral components of impulsivity (i.e., poor response inhibition, poor attentional inhibition, and increased risk-taking) were associated with quantity and frequency of alcohol consumption in a group of young adult social drinkers with ADHD (n = 33) and in a comparison control group (n = 21). Participants performed the delayed ocular return task (attentional inhibition), the cued go/no-go task (behavioral inhibition), and the balloon analogue risk task (risk-taking).

RESULTS

Both poor behavioral inhibition and greater risk-taking were related to greater quantity of consumption in the entire sample, whereas poor attentional inhibition was related to greater quantity specifically among those with ADHD. By contrast, only risk-taking was associated with frequency of consumption, and this was found specifically in the control group.

CONCLUSIONS

These findings provide important information regarding the potential role of distinct behavioral components of impulsivity in drinking behavior, and highlight unique relevance of attentional impairments to drinking behavior in those with ADHD.

Attention to social threat as a vulnerability to the development of comorbid social anxiety disorder and alcohol use disorders: an avoidance-coping cognitive model

Despite the frequent comorbidity of social anxiety disorder and alcohol use disorders, no theoretical model currently exists to explain the specific mechanisms underlying the comorbidity between these two disorders. An integration of existing theoretical models and empirical evidence across the social anxiety and alcohol use literatures is presented as the Avoidance-Coping Cognitive Model, which proposes that socially anxious individuals may be particularly vulnerable to the anxiolytic effects of alcohol through reductions in attention biases to social threat. The disproportionate reduction in anxiety may then make alcohol an attractive method of avoidance coping. Gaps in the empirical literature are reviewed in light of this model as future directions are suggested.

Acute effects of alcohol on intrusive memory development and viewpoint dependence in spatial memory support a dual representation model

BACKGROUND

A dual representation model of intrusive memory proposes that personally experienced events give rise to two types of representation: an image-based, egocentric representation based on sensory-perceptual features; and a more abstract, allocentric representation that incorporates spatiotemporal context. The model proposes that intrusions reflect involuntary reactivation of egocentric representations in the absence of a corresponding allocentric representation. We tested the model by investigating the effect of alcohol on intrusive memories and, concurrently, on egocentric and allocentric spatial memory.

METHODS

With a double-blind independent group design participants were administered alcohol (.4 or .8 g/kg) or placebo. A virtual environment was used to present objects and test recognition memory from the same viewpoint as presentation (tapping egocentric memory) or a shifted viewpoint (tapping allocentric memory). Participants were also exposed to a trauma video and required to detail intrusive memories for 7 days, after which explicit memory was assessed.

RESULTS

There was a selective impairment of shifted-view recognition after the low dose of alcohol, whereas the high dose induced a global impairment in same-view and shifted-view conditions. Alcohol showed a dose-dependent inverted "U"-shaped effect on intrusions, with only the low dose increasing the number of intrusions, replicating previous work. When same-view recognition was intact, decrements in shifted-view recognition were associated with increases in intrusions.

CONCLUSIONS

The differential effect of alcohol on intrusive memories and on same/shifted-view recognition support a dual representation model in which intrusions might reflect an imbalance between two types of memory representation. These findings highlight important clinical implications, given alcohol's involvement in real-life trauma.

Moderate alcohol disrupts a mechanism for detection of rare events in human visual cortex

Moderate doses of alcohol (blood alcohol concentration [BAC] of about 0.05%) may result in acute impairments at various levels of information processing. A number of reports have documented detrimental effects of moderate alcohol on the mismatch negativity (MMN), the electrocortical manifestation of a rapid (100 ms poststimulus) mechanism dedicated to the detection of unexpected auditory change (e.g., Jääskeläinen, et al., 1995). Recently, we and others identified a partial visual counterpart of the MMN, sometimes called the rareness-related negativity (RRN). Analogous to the MMN, the RRN evolves at about 100 ms after the unexpected change and was localized in visual cortex (Kenemans, et al., 2003). Rapid detection of unexpected events is important for everyday-life conditions like driving, prompting the question whether the visual RRN shows sensitivity to moderate alcohol similar to the MMN. In all, 16 subjects were tested either under moderate alcohol or under placebo. Unexpected visual change was implemented by presenting 2.4 versus 0.6 c/d gratings in pseudorandom sequences according to a deviant (10%)/standard (90%) schedule. The alcohol effects on MMN reported before were replicated. Furthermore, the RRN, defined as the difference between deviant and standard event-related potentials between 120 and 170 ms at Oz, was present under placebo but not under alcohol. It is concluded that moderate alcohol does indeed impair the rapid detection in visual cortex of unexpected changes. In contrast, electrocortical correlates of lower level sensory processing were still significantly present under alcohol.

Acute alcohol effects on inhibitory control and implicit cognition: implications for loss of control over drinking

Alcohol impairs inhibitory control, and it alters implicit alcohol cognitions including attentional bias and implicit associations. These effects are seen after doses of alcohol which do not lead to global impairments in cognitive performance. We review studies which demonstrate that the effects of alcohol on inhibitory control are associated with the ability of alcohol to prime alcohol-seeking behavior. We also hypothesize that alcohol-induced changes in implicit alcohol cognitions may partially mediate alcohol-induced priming of the motivation to drink. Based on contemporary theoretical models and conceptualizations of executive function, impulsivity, and the motivational salience of alcohol-related cues, we speculate on other aspects of cognition that may underlie alcohol's effects on alcohol seeking. Inconsistencies in existing research and priorities for future research are highlighted, including dose effects and the potential interactions between chronic heavy drinking and the acute effects of alcohol on these cognitive processes.

Alcohol intoxication at 0.06 and 0.10% blood alcohol concentration changes segmental body movement coordination

Alcohol intoxication is the cause of many falls requiring emergency care. The control of upright standing balance is complex and comprises contributions from several partly independent mechanisms like coordination, feedback and feedforward control and adaptation. Analysis of the segmental body movement coordination offers one option to detect the severity of balance problems. The study aims were (1) to investigate whether alcohol intoxication at 0.06 and 0.10% blood alcohol concentration (BAC) affected the segmental movement pattern under unperturbed and perturbed standing; (2) whether alcohol affected the ability for movement pattern adaptation; (3) whether one's own subjective feeling of drunkenness correlated to the movement pattern used. Twenty-five participants (13 women and 12 men, mean age 25.1 years) performed tests involving alcohol intoxication. Body movements were recorded at five locations (ankle, knee, hip, shoulder and head) during quiet standing and pseudorandom pulses of calf muscle vibration for 200 s with eyes closed or open. There was no significant effect of alcohol on the general movement pattern in unperturbed stance or on adaptation. However, when balance was repeatedly perturbed, knee movements became significantly less correlated to other body movements over time at 0.10% BAC and when visual information was unavailable, suggesting that the normal movement pattern could not be maintained for a longer period of time while under 0.10% BAC intoxication. Subjective feelings of drunkenness correlated often with a changed upper body movement pattern but less so with changed knee movements. Thus, an inability to relate drunkenness with changed knee movements may be a contributing factor to falls in addition to the direct effect of alcohol intoxication.

Directed Attention as a Common Resource for Executive Functioning and Self-Regulation

Research on executive functioning and on self-regulation have each identified a critical resource that is central to that domain and is susceptible to depletion. In addition, studies have shown that self-regulation tasks and executive-functioning tasks interact with each other, suggesting that they may share resources. Other research has focused specifically on restoring what we propose is the shared resource between self-regulation and executive functioning. Utilizing a theory-based natural environment intervention, these studies have found improvements in executive-functioning performance and self-regulation effectiveness, suggesting that the natural environment intervention restores this shared resource.

Decreases in recollective experience following acute alcohol: a dose-response study

RATIONALE

Acute alcohol intoxication induces a selective impairment of recognition memory associated with conscious recollection whilst recognition based on familiarity is left intact.

OBJECTIVES

We aimed to further elucidate the acute effects of alcohol on recognition memory by assessing three different doses of alcohol and examining the way in which this affected the recollection and familiarity components of recognition memory in comparison to a placebo group.

METHODS

A double-blind independent design was used, and participants received either alcohol (0.4, 0.6 or 0.8 g/kg) or a placebo drink. Participants encoded word pairs with depth of processing manipulated under generate and read conditions. Recognition memory was assessed and recollective awareness was examined through use of the remember-know procedure.

RESULTS

Alcohol produced a dose-dependent reduction in recognition memory associated with recollection, evidenced by decreases in the number of correctly recognised items with 'remember' responses compared to placebo. Recognition based on a familiarity, evidenced by 'know' responses, showed no differences between groups or pattern of reduction compared to the placebo group. However, a negative correlation was found between recognition based on familiarity and levels of intoxication.

CONCLUSIONS

Alcohol-induced impairments in recognition memory occur in a dose-dependent manner, specifically driven by reductions in recognition associated with conscious awareness.