The effects of alcohol on prose memory

Alcohol and Relatively Pure Cannabis Use, but Not Schizotypy, are Associated with Cognitive Attenuations

Elevated schizotypy relates to similar cognitive attenuations as seen in psychosis and cannabis/polydrug use. Also, in schizotypal populations cannabis and polydrug (including licit drug) use are enhanced. These cognitive attenuations may therefore either be a behavioral marker of psychotic (-like) symptoms or the consequence of enhanced drug use in schizotypal populations. To elucidate this, we investigated the link between cognitive attenuation and cannabis use in largely pure cannabis users (35) and non-using controls (48), accounting for the potential additional influence of both schizotypy and licit drug use (alcohol, nicotine). Cognitive attenuations commonly seen in psychosis were associated with cannabis and alcohol use, but not schizotypy. Future studies should therefore consider (i) non-excessive licit substance use (e.g., alcohol) in studies investigating the effect of cannabis use on cognition and (ii) both enhanced illicit and licit substance use in studies investigating cognition in schizotypal populations.

Using Virtual Reality to Study Alcohol Intoxication Effects on the Neural Correlates of Simulated Driving

The use of virtual reality in the form of simulated tasks can provide a realistic environment in which to study complex naturalistic behaviors. Many of the behavioral effects of alcohol intoxication are well known, but there is relatively little imaging evidence examining how alcohol exposure might transiently modulate brain function, especially in the context of task performance. In this review, we provide a brief synopsis of previous work using functional magnetic resonance imaging (fMRI) to study the neural correlates of alcohol intoxication. We describe in detail two studies from our published work, the first involving a visual perception paradigm, and the second involving virtual reality through a naturalistic behavior; simulated driving. Participants received single-blind individualized doses of beverage alcohol designed to produce blood alcohol content (BAC) of 0.04 and 0.08 or placebo. Subjects were fMRI scanned after training to asymptote performance. In both studies we found specific circuits that were differentially modulated by alcohol, we revealed both global and local effects of alcohol, and we examined relationships between behavior, brain function, and alcohol blood levels.

Alcohol-induced impairment and enhancement of memory: A test of the interference theory

Many studies have found cognitive deficits related to alcohol consumption. However, few studies have studied cognitive performance when alcohol was administered after the to-be-remembered information was presented with memory testing occurring when participants are once again sober. The present study examined effects of alcohol on cognitive performance using a prose recall task during acute intoxication and a post-trial recall task for prose passages that had been presented before intoxication. Fifty-one men were given either 2.0 g/kg of 100 proof (50% absolute ethanol) vodka or a placebo. In the present study, evidence was found of acute alcohol impairment in prose memory, along with alcohol facilitation of memory on a post-trial task.

Effects of alcohol consumption and alcohol susceptibility on cognition: a psychophysiological examination

The present study sought to examine acute effects of alcohol on cognitive processing and performance within the context of two prominent theories of alcohol's effects; namely, that alcohol restricts the focus of attention (e.g. Steele and Josephs, 1990. Journal of Abnormal Psychology, 97, 196-205) and that alcohol impairs response inhibition (e.g. Fillmore and Vogel-Sprott, 1999. Experimental and Clinical Psychopharmacology, 7, 49-55; Fillmore and Vogel-Sprott, 2000. Journal of Studies on Alcohol, 61, 239-246). Forty-five participants were randomly assigned to receive either a placebo level of alcohol (0.04 g/kg), a moderate dose (0.40 g/kg), or a higher dose (0.80 g/kg). Brain electrical activity (ERPs) and behavioral responses (reaction time and accuracy) were measured while participants performed a modified flanker task, in which a target letter was flanked by response-compatible or response-incompatible letters. Analyses of behavioral data showed that alcohol increased response competition in accuracy but not response times, suggesting that alcohol influences response selection more than attentional processes per se. This finding is in-line with predictions derived from the response inhibition model. ERP latency data provided mixed support for both models. ERP amplitude data showed that the high dose of alcohol primarily influenced a mostly frontal negativity in the ERP, present on both correct and incorrect response trials. Differences in self-reported susceptibility to alcohol were most evident in the amplitude of the P3 component. Findings are discussed in terms of the differential effects of acute dose and susceptibility on information processing.

The effect of moderate levels of simulated altitude on sustained cognitive performance

Previous work has documented cognitive deficits at high altitudes (15,000-25,000 ft), but there is controversy for lower altitudes. This study looked at the effects of moderate altitudes--12,500 ft and 15,000 ft--on short-term memory in comparison to 2,000 ft. Seventy-two student pilots and instructors were first administered the Vocabulary, Digit Span, and Digit Symbol subtests from the Wechsler Adult Intelligence Scale-Revised, the Vandenberg Mental Rotation Test, and the near-contrast sensitivity portion of the Vistech VCTS 6000 chart. Participants then spent 1 1/2 hr at their designated altitude for cognitive testing. Participants performed a 30 min vigilance task while listening to an audiotape with instructions to recall radio calls prefaced by their assigned call sign. Half of the radio calls were high memory loads (at least 4 pieces of information), and half were low memory loads (no more than 2 pieces of information). No effects of altitude were found in performance on the Vigilance task. However, for readbacks of high memory load, significant deficits in recall were observed at 12,500 ft and 15,000 ft, whereas no effect of altitude was observed on recall of readbacks with low memory loads. These results indicate that, at altitude, short-term memory was exceeded for the readbacks requiring a larger amount of information to be recalled, and that cognitive deficits are found at lower altitudes than previously observed.

The effect of Ginkgo biloba on memory in healthy male volunteers

The purpose of this study was to investigate possible effects of Ginkgo biloba, a widely used herbal extract, on memory. This study incorporated a double-blind, placebo-controlled design, which used 30 healthy male subjects in each of two groups. The treatment group received two 60-mg tablets of BioGinkgo (27/7) [corrected] daily for 5 days, while the placebo group received a placebo. On the fifth day, after a 2-h waiting period, all subjects were given the Sternberg Memory Scanning Test [Q. J. Exp. Psychol. 27 (1975) 1.], a reaction time control test, the vocabulary and digit span subtests of the WAIS-R [Wechsler D. Manual for the Wechsler adult intelligence scale - revised. New York: Psychological Corporation, 1981.], a reading span test [J. Verbal Learn. Verbal Behav. 19 (1980) 450.] and a prose recall test [Discourse Proc. 13 (1990) 387.]. Blood pressure, heart rate and side effects were also monitored throughout the study. Nonsignificant results were found on all interactions involving treatment group on all tests except the Sternberg Memory Scanning Test. The extract appeared to be safe but largely ineffective in enhancing memory.

Posttrial treatment with ethanol enhances recall of prose narratives

A small number of studies have examined the effects of postlearning alcohol intoxication on memory for various materials. In contrast to most research examining the effects of alcohol on human memory, these studies demonstrated a facilitation of memory for information learned prior to intoxication. The present study was designed to examine the effects of alcohol on memory for two different kinds of materials. Standard word lists and narrative prose passages were employed to obtain a more detailed picture of the effects of posttrial intoxication with alcohol on memory. Intoxication with alcohol did not affect subject's ability to recall simple word lists. However, recall of prose passages was facilitated to a statistically significant degree. Results are discussed within the context of a current theory of retrograde facilitation of memory via various drugs/substances.

Gender differences in retrieval from long-term memory following acute intoxication with ethanol

The present study investigated the effects of ethanol on retrieval from long-term memory by using a set of cognitive decision tasks. Male and female subjects were administered either 0.0 or 1.0 milliliter of ethanol per kilogram of body weight, and then asked to make physical, lexical, and semantic decisions about pairs of words. In general, intoxicated subjects responded significantly slower than sober subjects on all decision types. In addition, female subjects demonstrated greater performance deficits than males when intoxicated. The results suggested that the reduction in speed was not due to a simple slowing of motor responses. Rather the ethanol induced memory deficits may result from the slowing of cognitive operations that impair the efficiency of working memory. Several reasons were proposed for the observed difference in reaction to intoxication between male and female subjects, including neuroendocrine processes and cognitive differences.