Alberto Crego

Executive functioning and alcohol binge drinking in university students

BACKGROUND Binge drinking (BD) is prevalent among college students. Studies on alcoholism have shown that the prefrontal cortex is vulnerable to the neurotoxic effects of alcohol. The prefrontal cortex undergoes both structural and functional changes during adolescence and young adulthood. Sex differences have been observed in brain maturation and in alcohol-induced damage. The objective of the present study was to analyze the relationship between BD and cognitive functions subserved by the prefrontal cortex in male and female university students. METHODS The sample comprised 122 undergraduates (aged 18 to 20 years): 62 BD (30 females) and 60 non-BD (29 females). Executive functions were assessed by WMS-III (Backward Digit Span and Backward Spatial Span), SOPT (abstract designs), Letter Fluency (PMR), BADS (Zoo Map and Key Search) and WCST-3. RESULTS BD students scored lower in the Backward Digit Span Subtest and generated more perseverative responses in the SOPT In relation to interaction BD by sex, BD males scored lower in the Backward Digit Span test than BD females and non-BD males. CONCLUSIONS BD is associated with poorer performance of executive functions subserved by the dorsolateral prefrontal cortex. The results do not support enhanced vulnerability of women to alcohol neurotoxic effects. These difficulties may reflect developmental delay or frontal lobe dysfunction.

Reduced anterior prefrontal cortex activation in young binge drinkers during a visual working memory task.

Working memory (WM) is a major cognitive function that is altered by chronic alcohol consumption. This impairment has been linked to alterations in the hippocampus and prefrontal cortex (PFC). Animal and human studies have shown that the adolescent brain is more sensitive to the neurotoxic effects of alcohol than the adult brain, particularly those structures that mature late on in development, such as the hippocampus and prefrontal brain. The aim of the present study was to assess visual working memory and its neural correlates in young university students who partake in intermittent consumption of large amounts of alcohol (binge drinkers). A sample of 42 binge drinkers and 53 corresponding control subjects performed an identical pairs continuous performance task (IP-CPT) in a combined event-related potential (ERP) and exact low-resolution brain electromagnetic tomography (eLORETA) study. The results revealed that, despite adequate performance, binge drinkers showed a smaller late positive component (LPC) associated with hypoactivation of the right anterior prefrontal cortex (aPFC) for matching stimuli, in comparison with control subjects. These findings may reveal binge drinking-related functional alteration in recognition working memory processes and suggest that impaired prefrontal cortex function may occur at an early age in binge drinkers.

Hyperactivation of right inferior frontal cortex in young binge drinkers during response inhibition: a follow-up study.

AIMS The objective of this study was to examine brain activity, with particular attention to prefrontal function, during response execution and inhibition in youths who have engaged in binge drinking (BD) for at least 2 years. DESIGN Event-related potentials (ERPs) were recorded twice within 3 years, during performance of a Go/NoGo task. SETTING The study was part of a longitudinal study of the neurocognitive effects of BD. PARTICIPANTS A total of 48 undergraduate students, 25 controls (14 females) and 23 binge drinkers (10 females), with no personal or family history of alcoholism or psychopathological disorders. MEASUREMENTS The Go-P3 and NoGo-P3 components of the ERPs were examined by principal component analysis and exact low-resolution tomography analysis (eLORETA). FINDINGS Binge drinkers showed larger Go-P3 amplitudes than controls in the first and second evaluations (P = 0.019). They also showed larger NoGo-P3 amplitude in the second evaluation (P = 0.002). eLORETA analyses in the second evaluation revealed significantly greater activation of the right inferior frontal cortex (rIFC) in binge drinkers than in controls during successful inhibition (P < 0.05). CONCLUSIONS Young binge drinkers appear to show abnormal brain activity as measured by event-related potentials during response execution and inhibition which may represent a neural antecedent of difficulties in impulse control.

Binge drinking trajectory and neuropsychological functioning among university students: A longitudinal study

BACKGROUND Adolescence is a time of considerable neurodevelopment. Binge drinking (BD) during this period increases the vulnerability to its neurotoxic effects. This longitudinal study aimed to investigate the relationship between BD trajectory over university years and neuropsychological functioning. METHODS Cohort-study. Two-year follow-up. A total of 89 university students were assessed: 40 Non-BD (at Initial and Follow-up), 16 Ex-BD (BD at Initial but not at Follow-up) and 33 BD (at both times). Neuropsychological assessment of working memory, episodic memory and executive abilities was carried out during their first (Initial) and third (Follow-up) academic year at the University of Santiago de Compostela. RESULTS BD subjects performed less well on the Wechsler Memory Scale-III (WMS-III) Logical Memory Subtest (immediate theme recall, P=.034; delayed theme recall, P=.037; and percent retention, P=.035) and committed more perseverative errors on the Self-Ordered Pointing Task (SOPT) (P=.021) than Non-BD. There were no differences between Ex-BD and Non-BD. CONCLUSIONS Binge drinking trajectory during adolescence is associated with neuropsychological performance. Persistent BD, but not Ex-BD, is associated with verbal memory and monitoring difficulties. This is compatible with the hypothesis that heavy alcohol use during adolescence may affect cognitive functions that rely on the temporomesial and dorsolateral prefrontal cortex.

Effects of a Persistent Binge Drinking Pattern of Alcohol Consumption in Young People: A Follow-Up Study Using Event-Related Potentials

AIMS The objective of this study was to examine brain activity related to visual attention processes in youths who had maintained a binge drinking (BD) pattern of alcohol consumption for >2 years. METHODS The participants were 57 university students (26 binge drinkers: BDs) with no personal or family history of alcoholism or psychopathological disorders in first-degree relatives. Event-related potentials (ERPs) were recorded while participants performed a visual oddball task (twice within a 2-year interval). The latency and amplitude of the P3b component of the ERPs were analysed. RESULTS The P3b amplitude was larger in young BDs than in aged-matched controls at both evaluation times, and the difference was more pronounced after 2 years of maintenance of a BD pattern of consumption. The larger P3b amplitude was associated with an earlier onset of regular drinking and with a greater quantity and intensity of consumption. CONCLUSIONS These findings suggest that young BDs exhibit anomalies in neural activity involved in attentional/working memory processes, which increase after 2 years of maintenance of BD. This anomalous neural activity may reflect underlying dysfunctions in neurophysiological mechanisms as well as the recruitment of additional attentional/working memory resources to enable the binge drinkers to perform the task adequately.

Binge Drinking and Declarative Memory in University Students

BACKGROUND Binge drinking (BD), which is characterized by sporadic consumption of large quantities of alcohol in short periods, is prevalent among university students. Animal studies have shown that BD is associated with damage to the hippocampus, a region of the brain that plays a key role in learning and memory. The temporal cortex undergoes structural and functional changes during adolescence. The aim of the present study was to examine the association between BD and declarative memory in male and female university students. METHODS The participants were 122 students (between 18 and 20 years of age): 62 BD (30 women) and 60 non-BD (29 women). The neuropsychological assessment included the Rey Auditory Verbal Learning Test (RAVLT) and Weschler Memory Scale-3rd ed. (WMS-III) Logical Memory subtest, to evaluate verbal declarative memory, and the WMS-III Family Pictures subtest, to measure visual declarative memory. RESULTS The BD students remembered fewer words in the interference list and displayed greater proactive interference in the RAVLT; they performed worse in the Logical Memory subtest, both on immediate and delayed recall. There were no differences between the groups in performance of the Family Pictures subtest. No significant interactions were observed between BD and sex. CONCLUSIONS Binge drinking is associated with poorer verbal declarative memory, regardless of sex. The findings are consistent with the vulnerability of the adolescent hippocampus to the neurotoxic effects of alcohol. Longitudinal studies will help determine the nature of this relationship, the neurodevelopmental trajectories for each sex, and the repercussions on academic performance.

Increased amplitude of P3 event-related potential in young binge drinkers.

The aim of the present study was to determine how binge drinking (BD) affects brain functioning in male and female university students during the performance of a visual discrimination task. Thirty two binge drinkers and 53 controls (non binge drinkers), with no history of other drug use, personal or family history of alcoholism or psychopathological disorders, were selected. Event-related potentials (ERPs) were recorded during the performance of a visual oddball task. The latency and amplitude of the N2 and P3b components of the ERPs were analyzed. There were no differences between the groups in behavioral measures, but P3b amplitudes were significantly larger in binge drinkers than controls. This may suggest the presence of anomalies in neural processes mediating attention processing, or an imbalance (increased) of neuronal activity in P3b generators caused by the presence of BD pattern for a long time.

Developmental trajectory of the prefrontal cortex: a systematic review of diffusion tensor imaging studies

Fluctuations in gray and white matter volumes in addition to the fibers’ reorganization and refinement of synaptic connectivity apparently happen in a particular temporo-spatial sequence during the dynamic and prolonged process of cerebral maturation. These developmental events are associated with regional modifications of brain tissues and neural circuits, contributing to networks’ specialization and enhanced cognitive processing. According to several studies, improvements in cognitive processes are possibly myelin-dependent and associated to white matter maturation. Of particular interest is the developmental pattern of the prefrontal cortex (PFC), more specifically the PFC white matter, due to its role in high-level executive processes such as attention, working memory and inhibitory control. A systematic review of the literature was conducted using the Web of Science, PubMed and Embase databases to analyze the development of PFC white matter using Diffusion Tensor Imaging (DTI), a widely used non-invasive technique to assess white matter maturation. Both the research and reporting of results were based on Cochrane’s recommendations and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Information extracted from 27 published studies revealed an increased myelination, organization and integrity of frontal white matter with age, as revealed by DTI indexes (fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD] and axial diffusivity [AD]). These patterns highlight the extended developmental course of the frontal structural connectivity, which parallels the improvements in higher-level cognitive functions observed between adolescence and early adulthood.

Electrophysiological Anomalies in Face–Name Memory Encoding in Young Binge Drinkers

A growing body of evidence indicates that the intake of large amounts of alcohol during one session may have structural and functional effects on the still-maturing brains of young people. These effects are particularly pronounced in prefrontal and hippocampal regions, which appear to be especially sensitive to the neurotoxic effects of alcohol. However, to date, few studies have used the event-related potentials (ERPs) technique to analyze the relationship between binge drinking (BD) and associative memory. The objective of this study was to examine brain activity during memory encoding using the Subsequent memory paradigm in subjects who have followed a BD pattern of alcohol consumption for at least 2 years. A total of 50 undergraduate students (mean age = 20.6 years), i.e., 25 controls (12 females) and 25 binge drinkers (BDs; 11 females), with no personal or family history of alcoholism or psychopathological disorders, performed a visual face–name association memory task. The task used enables assessment of the Difference due to memory effect (Dm), a measure of memory encoding based on comparison of the neural activity associated with subsequent successful and unsuccessful retrieval. In ERP studies, study items that are subsequently remembered elicit larger positive amplitudes at midline parieto-frontal sites than those items that are subsequently forgotten. The Dm effect generally appears in the latency range of about 300–800 ms. The results showed a Dm effect in posterior regions in the 350–650 ms latency range in the Control group. However, in the BD group, no significant differences were observed in the electrophysiological brain activity between remembered and forgotten items during the encoding process. No differences between groups were found in behavioral performance. These findings show that young BDs display abnormal pattern of ERP brain activity during the encoding phase of a visual face–name association task, possibly suggesting a different neural signature of successful memory encoding.

The Brain of Binge Drinkers at Rest: Alterations in Theta and Beta Oscillations in First-Year College Students with a Binge Drinking Pattern

Background: Previous studies have reported anomalous resting brain activity in the electroencephalogram (EEG) of alcoholics, often reflected as increased power in the beta and theta frequency bands. The effects of binge drinking, the most common pattern of excessive alcohol consumption during adolescence and youth, on brain activity at rest is still poorly known. In this study, we sought to assess the pattern of resting-state EEG oscillations in college-aged binge drinkers (BDs). Methods: Resting-state brain activity during eyes-open and eyes-closed conditions was recorded from 60 channels in 80 first-year undergraduate students (40 controls and 40 BDs). Cortical sources activity of EEG rhythms was estimated using exact Low-Resolution Electromagnetic Tomography (eLORETA) analysis. Results: EEG-source localization analysis revealed that BDs showed, in comparison with controls, significantly higher intracranial current density in the beta frequency band over the right temporal lobe (parahippocampal and fusiform gyri) during eyes-open resting state as well as higher intracranial current density in the theta band over the bilateral occipital cortex (cuneus and lingual gyrus) during eyes-closed resting condition. Conclusions: These findings are in line with previous results observing increased beta and/or theta power following chronic or heavy alcohol drinking in alcohol-dependent subjects and BDs. Increased tonic beta and theta oscillations are suggestive of an augmented cortical excitability and of potential difficulties in the information processing capacity in young BDs. Furthermore, enhanced EEG power in these frequency bands may respond to a neuromaturational delay as a result of excessive alcohol consumption during this critical brain developmental period.