Memory for emotional picture cues during acute alcohol intoxication

Agmatine alleviates ethanol withdrawal-associated cognitive impairment and neurochemical imbalance in rats

The present study aimed to investigate the role of agmatine in the neurobiology underlying memory impairment during ethanol withdrawal in rats. Sprague-Dawley rats were subjected to a 21-day chronic ethanol exposure regimen (2.4 % w/v ethanol for 3 days, 4.8 % w/v for the next 4 days, and 7.2 % w/v for the following 14 days), followed by a withdrawal period. Memory impairment was assessed using the passive avoidance test (PAT) at 24, 48, and 72 h post-withdrawal. The ethanol-withdrawn rats displayed a significant decrease in step-through latency in the PAT, indicative of memory impairment at 72 h post-withdrawal. However, administration of agmatine (40 µg/rat) and its modulators (L-arginine, arcaine, and amino-guanidine) significantly increases the latency time in the ethanol-withdrawn rats, demonstrating the attenuation of memory impairment. Further, pretreatment with imidazoline receptor agonists enhances agmatine's effects, while antagonists block them, implicating imidazoline receptors in agmatine's actions. Neurochemical analysis in ethanol-withdrawn rats reveals dysregulated glutamate and GABA levels, which was attenuated by agmatine and its modulators. By examining the effects of agmatine administration and modulators of endogenous agmatine, the study aimed to shed light on the potential therapeutic implications of agmatinergic signaling in alcohol addiction and related cognitive deficits. Thus, the present findings suggest that agmatine administration and modulation of endogenous agmatine levels hold potential as therapeutic strategies for managing alcohol addiction and associated cognitive deficits. Understanding the neurobiology underlying these effects paves the way for the development of novel interventions targeting agmatinergic signaling in addiction treatment.

Alcohol and morality: one alcoholic drink is enough to make people declare to harm others and behave impurely

We aimed to understand if alcohol intoxication affects the willingness to violate moral foundations (care, fairness, authority, loyalty, and purity). We conducted a laboratory study (N = 387) with three randomized groups: alcohol intoxication, placebo, and control, measuring the sacralization of moral foundations via the Moral Foundations Sacredness Scale. The study showed intoxicated participants sacralized moral foundations of care and purity more often than participants from control and placebo groups. It means participants declared more willing to physically harm other people and animals and behave impurely, e.g., doing deviant sexual behaviors or selling their souls. No differences related to fairness, authority, and loyalty were found. Our study helps to understand the decision processes underlying immoral behaviors, including crimes. We showed that even one drink makes people change their judgments about what is right and wrong (in the cases of harmful and impure behaviors), and because this kind of judgment precedes immoral behaviors, our results may help explain why some people under the influence of alcohol break the rules by doing things which they would never do when sober.

The Acute Effects of Psychoactive Drugs on Emotional Episodic Memory Encoding, Consolidation, and Retrieval

Psychoactive drugs modulate learning and emotional processes in ways that could impact their recreational and medical use. Recent work has revealed how drugs impact different stages of processing emotional episodic memories, specifically encoding (forming memories), consolidation (stabilizing memories), and retrieval (accessing memories). Drugs administered before encoding may preferentially impair (e.g., GABA_A sedatives including alcohol and benzodiazepines, Δ⁹-tetrahydrocannabinol or THC, ketamine), enhance (e.g., dextroamphetamine and dextromethamphetamine), or both impair and enhance (i.e., ±3,4-methylenedioxymethylamphetamine or MDMA) emotionally negative and positive compared to neutral memories. GABA_A sedatives administered immediately post-encoding (during consolidation) can preferentially enhance emotional memories, though this selectivity may decline or even reverse (i.e., preferential enhancement of neutral memories) as the delay between encoding and retrieval increases. Finally, retrieving memories under the effects of THC, dextroamphetamine, MDMA, and perhaps GABA_A sedatives distorts memory, with potentially greater selectively for emotional (especially positive) memories. We review these effects, propose neural mechanisms, discuss methodological considerations for future work, and speculate how drug effects on emotional episodic memory may contribute to drug use and abuse.

A strong alcoholic drink does not influence self-assessments of the big five personality traits

cAlohol affects how people think, feel, and behave, and how they perceive the physical and social world around them. But does alcohol also influence how people perceive themselves? Past work points to a number of possibilities, suggesting intoxication could lead to positive biases, to negative biases, or have no effects on self-assessments at all. Here we tested whether alcoholic intoxication affects self-assessments of personality within the Big Five personality framework. We hypothesized that intoxicated participants would see themselves more positively than non-intoxicated individuals would. We conducted a preregistered laboratory experiment on participants divided into three groups: alcohol intoxication (n = 106), placebo (n = 114), and control conditions (n = 109). Contrary to predictions, we found no differences in self-assessments of personality across conditions. Findings point to the possibility that self-assessments of personality may be too stable to be affected by the momentary changes in thoughts and feelings caused by alcoholic intoxication.

Alcohol intoxication, but not hangover, differentially impairs learning and automatization of complex motor response sequences

Behavioral automatization usually makes us more efficient and less error-prone, but may also foster dysfunctional behavior like alcohol abuse. Yet, it has remained unclear whether alcohol itself causes the shift from controlled to habitual behavior commonly observed in alcohol use disorder (AUD). We thus investigated how the acute and post-acute effects of binge drinking affect the automatization of motor response sequences and the execution of automated vs. controlled motor response sequences. N = 70 healthy young men performed a newly developed automatization paradigm once sober and once after binge drinking (half of them intoxicated and half of them hungover). While we found no significant effects of alcohol hangover, acute intoxication (~ 1.2 ‰) had two dissociable effects: Firstly, it impaired the automatization of complex motor response sequence execution. Secondly, it eliminated learning effects in response selection and pre-motor planning processes. The results suggest that alcohol hangover did not affect controlled or automated processes, and disprove the assumption that alcohol intoxication generally spares or facilitates motor response sequence automatization. As these effects could be specific to the investigated explicit learning context, acute intoxication might potentially still improve the execution of pre-existing automatisms and/or the implicit acquisition of motor response sequence automatisms.

Forgotten but not gone: FMRI evidence of implicit memory for negative stimuli 24 hours after the initial study episode

Endel Tulving conducted pioneering work on the explicit and implicit memory systems and demonstrated that priming effects can be long-lasting. It is also well-established that emotion can amplify explicit and implicit memory. Prior work has utilized repetition suppression (RS) of the fMRI-BOLD signal-a reduction in the magnitude of activity over repeated presentations of stimuli-to index implicit memory. Using an explicit recognition memory paradigm, we examined emotional modulation of long-term implicit memory effects as revealed by repetition suppression (i.e., comparing second-exposure forgotten items to first-exposure correct rejections). Forty-seven participants incidentally encoded line-drawings of negative, positive, and neutral scenes followed by the full color image. Twenty-four hours later, participants underwent fMRI during a recognition memory test in which old and new line-drawings were presented. Implicit and explicit memory effects were defined by the contrasts of New-Correct Rejections > Old-Misses and Old-Hits > New-Correct Rejections, respectively. Wide-spread Negative RS was found in frontal and occipito-temporal cortex that was greater than Neutral RS in the right orbito-frontal cortex and inferior frontal gyri. Valence-specific Negative RS, compared to Positive RS, was observed in the left inferior occipital gyrus. There was no strong evidence for emotional modulation of amygdala RS, but functional connectivity analyses revealed valence-specificity: Negative and positive valence were associated with repetition suppression and repetition enhancement of amygdala-occipital connectivity, respectively. Negative implicit memory patterns in most frontal regions-but not occipital areas-overlapped with explicit memory effects. Thus, implicit memory effects for a single visual stimulus presentation are modulated by emotional valence, can be observed 24hours after initial exposure, and show some overlap with explicit memory.

Acute alcohol and cognition: Remembering what it causes us to forget

Addiction has been conceptualized as a specific form of memory that appropriates typically adaptive neural mechanisms of learning to produce the progressive spiral of drug-seeking and drug-taking behavior, perpetuating the path to addiction through aberrant processes of drug-related learning and memory. From that perspective, to understand the development of alcohol use disorders, it is critical to identify how a single exposure to alcohol enters into or alters the processes of learning and memory, so that involvement of and changes in neuroplasticity processes responsible for learning and memory can be identified early. This review characterizes the effects produced by acute alcohol intoxication as a function of brain region and memory neurocircuitry. In general, exposure to ethanol doses that produce intoxicating effects causes consistent impairments in learning and memory processes mediated by specific brain circuitry, whereas lower doses either have no effect or produce a facilitation of memory under certain task conditions. Therefore, acute ethanol does not produce a global impairment of learning and memory, and can actually facilitate particular types of memory, perhaps particular types of memory that facilitate the development of excessive alcohol use. In addition, the effects on cognition are dependent on brain region, task demands, dose received, pharmacokinetics, and tolerance. Additionally, we explore the underlying alterations in neurophysiology produced by acute alcohol exposure that help to explain these changes in cognition and highlight future directions for research. Through understanding the impact that acute alcohol intoxication has on cognition, the preliminary changes potentially causing a problematic addiction memory can better be identified.

Acute Effects of Alcohol on Encoding and Consolidation of Memory for Emotional Stimuli

OBJECTIVE

Acute doses of alcohol impair memory when administered before encoding of emotionally neutral stimuli but enhance memory when administered immediately after encoding, potentially by affecting memory consolidation. Here, we examined whether alcohol produces similar biphasic effects on memory for positive or negative emotional stimuli.

METHOD

The current study examined memory for emotional stimuli after alcohol (0.8 g/kg) was administered either before stimulus viewing (encoding group; n = 20) or immediately following stimulus viewing (consolidation group; n = 20). A third group received placebo both before and after stimulus viewing (control group; n = 19). Participants viewed the stimuli on one day, and their retrieval was assessed exactly 48 hours later, when they performed a surprise cued recollection and recognition test of the stimuli in a drug-free state.

RESULTS

As in previous studies, alcohol administered before encoding impaired memory accuracy, whereas alcohol administered after encoding enhanced memory accuracy. Critically, alcohol effects on cued recollection depended on the valence of the emotional stimuli: Its memory-impairing effects during encoding were greatest for emotional stimuli, whereas its memory-enhancing effects during consolidation were greatest for emotionally neutral stimuli. Effects of alcohol on recognition were not related to stimulus valence.

CONCLUSIONS

This study extends previous findings with memory for neutral stimuli, showing that alcohol differentially affects the encoding and consolidation of memory for emotional stimuli. These effects of alcohol on memory for emotionally salient material may contribute to the development of alcohol-related problems, perhaps by dampening memory for adverse consequences of alcohol consumption.

Effect of Alcohol on Encoding and Consolidation of Memory for Alcohol-Related Images

BACKGROUND

Drug and alcohol abusers develop strong memories for drug-related stimuli. Preclinical studies suggest that such memories are a result of drug actions on reward pathways, which facilitate learning about drug-related stimuli. However, few controlled studies have investigated how drugs affect memory for drug-related stimuli in humans.

METHODS

The current study examined the direct effect of alcohol on memory for images of alcohol-related or neutral beverages. Participants received alcohol (0.8 g/kg) either before viewing visual images (encoding condition; n = 20) or immediately after viewing them (consolidation condition; n = 20). A third group received placebo both before and after viewing the images (control condition; n = 19). Memory retrieval was tested exactly 48 hours later, in a drug-free state.

RESULTS

Alcohol impaired memory in the encoding condition and enhanced memory in the consolidation condition, but these effects did not differ for alcohol-related and neutral beverage stimuli. However, in the encoding condition, participants who experienced greater alcohol-induced stimulation exhibited better memory for alcohol-related, but not neutral beverage stimuli.

CONCLUSIONS

These findings suggest that individual differences in sensitivity to the positive, rewarding effects of alcohol are associated with greater propensity to remember alcohol-related stimuli encountered while intoxicated. As such, stimulant responders may form stronger memory associations with alcohol-related stimuli, which might then influence their drinking behavior.

Drinkers' memory bias for alcohol picture cues in explicit and implicit memory tasks

BACKGROUND

Alcohol cues can bias attention and elicit emotional reactions, especially in drinkers. Yet, little is known about how alcohol cues affect explicit and implicit memory processes, and how memory for alcohol cues is affected by acute alcohol intoxication.

METHODS

Young adult participants (N=161) were randomly assigned to alcohol, placebo, or control beverage conditions. Following beverage consumption, they were shown neutral, emotional and alcohol-related pictures cues. Participants then completed free recall and repetition priming tasks to test explicit and implicit memory, respectively, for picture cues. Average blood alcohol concentration for the alcohol group was 74±13mg/dl when memory testing began. Two mixed linear model analyses were conducted to examine the effects of beverage condition, picture cue type, and their interaction on explicit and implicit memory.

RESULTS

Picture cue type and beverage condition each significantly affected explicit recall of picture cues, whereas only picture cue type significantly influenced repetition priming. Individuals in the alcohol condition recalled significantly fewer pictures than those in other conditions, regardless of cue type. Both free recall and repetition priming were greater for emotional and alcohol-related cues compared to neutral picture cues. No interaction effects were detected.

CONCLUSIONS

Young adult drinkers showed enhanced explicit and implicit memory processing of alcohol cues compared to emotionally neutral cues. This enhanced processing for alcohol cues was on par with that seen for positive emotional cues. Acute alcohol intoxication did not alter this preferential memory processing for alcohol cues over neutral cues.

Selective effects of acute alcohol intake on the prospective and retrospective components of a prospective-memory task with emotional targets

RATIONALE

Prospective memory involves remembering to do something in the future and has a prospective component (remembering that something must be done) and a retrospective component (remembering what must be done and when it must be done). Initial studies reported an impairment in prospective-memory performance due to acute alcohol consumption. Retrospective-memory studies demonstrated that alcohol effects vary depending on the emotionality of the information that needs to be learned.

OBJECTIVES

The aim of the present study was to investigate possible differential effects of a mild acute alcohol dose (0.4 g/kg) on the prospective and retrospective components of prospective memory depending on cue valence.

METHOD

Seventy-five participants were allocated to an alcohol or placebo group and performed a prospective-memory task in which prospective-memory cue valence was manipulated (negative, neutral, positive). The multinomial model of event-based prospective memory (Smith and Bayen 2004) was used to measure alcohol and valence effects on the two prospective-memory components separately.

RESULTS

Overall, no main effect of alcohol or valence on prospective-memory performance occurred. However, model-based analyses demonstrated a significantly higher retrospective component for positive compared with negative cues in the placebo group. In the alcohol group, the prospective component was weaker for negative than for neutral cues and the retrospective component was stronger for positive than for neutral cues. Group comparisons showed that the alcohol group had a significantly lower prospective component for negative cues and a lower retrospective component for neutral cues.

CONCLUSION

This is the first study to demonstrate selective alcohol effects on prospective-memory components depending on prospective-memory cue valence.

Acute ethanol withdrawal impairs contextual learning and enhances cued learning

BACKGROUND

Alcohol affects many of the brain regions and neural processes that support learning and memory, and these effects are thought to underlie, at least in part, the development of addiction. Although much work has been done regarding the effects of alcohol intoxication on learning and memory, little is known about the effects of acute withdrawal from a single alcohol exposure.

METHODS

We assess the effects of acute ethanol withdrawal (6 hours postinjection with 4 g/kg ethanol) on 2 forms of fear conditioning (delay and trace fear conditioning) in C57BL/6J and DBA/2J mice. The influence of a number of experimental parameters (pre- and post training withdrawal exposure; foreground/background processing; training strength; and nonassociative effects) is also investigated.

RESULTS

Acute ethanol withdrawal during training had a bidirectional effect on fear-conditioned responses, decreasing contextual responses and increasing cued responses. These effects were apparent for both trace and delay conditioning in DBA/2J mice and for trace conditioning in C57BL/6J mice; however, C57BL/6J mice were selectively resistant to the effects of acute withdrawal on delay cued responses.

CONCLUSIONS

Our results show that acute withdrawal from a single, initial ethanol exposure is sufficient to alter long-term learning in mice. In addition, the differences between the strains and conditioning paradigms used suggest that specific learning processes can be differentially affected by acute withdrawal in a manner that is distinct from the reported effects of both alcohol intoxication and withdrawal following chronic alcohol exposure. Thus, our results suggest a unique effect of acute alcohol withdrawal on learning and memory processes.

Memory for drug-related visual stimuli in young adult, cocaine-dependent polydrug users

BACKGROUND AND OBJECTIVES

Implicit (unconscious) and explicit (conscious) memory associations with drugs have been examined primarily using verbal cues. However, drug seeking, drug use behaviors, and relapse in chronic cocaine and other drug users are frequently triggered by viewing substance-related visual cues in the environment. We thus examined implicit and explicit memory for drug picture cues to understand the relative extent to which conscious and unconscious memory facilitation of visual drug cues occurs during cocaine dependence.

METHODS

Memory for drug-related and neutral picture cues was assessed in 14 inpatient cocaine-dependent polydrug users and a comparison group of 21 young adults with limited drug experience (n = 35). Participants completed picture cue exposure, free recall and recognition tasks to assess explicit memory, and a repetition priming task to assess implicit memory.

RESULTS

Drug cues, compared to neutral cues, were better explicitly recalled and implicitly primed, and especially so in the cocaine group. In contrast, neutral cues were better explicitly recognized, and especially in the control group.

CONCLUSION

Certain forms of explicit and implicit memory for drug cues were enhanced in cocaine users compared to controls when memory was tested a short time following cue exposure. Enhanced unconscious memory processing of drug cues in chronic cocaine users may be a behavioral manifestation of heightened drug cue salience that supports drug seeking and taking. There may be value in expanding intervention techniques to utilize cocaine users' implicit memory system.

A role for cognitive rehabilitation in increasing the effectiveness of treatment for alcohol use disorders

Neurocognitive impairments are prevalent in persons seeking treatment for alcohol use disorders (AUDs). These impairments and their physical, social, psychological and occupational consequences vary in severity across persons, much like those resulting from traumatic brain injury; however, due to their slower course of onset, alcohol-related cognitive impairments are often overlooked both within and outside of the treatment setting. Evidence suggests that cognitive impairments can impede treatment goals through their effects on treatment processes. Although some recovery of alcohol-related cognitive impairments often occurs after cessation of drinking (time-dependent recovery), the rate and extent of recovery is variable across cognitive domains and individuals. Following a long hiatus in scientific interest, a new generation of research aims to facilitate treatment process and improve AUD treatment outcomes by directly promoting cognitive recovery (experience-dependent recovery). This review updates knowledge about the nature and course of cognitive and brain impairments associated with AUD, including cognitive effects of adolescent AUD. We summarize current evidence for indirect and moderating relationships of cognitive impairment to treatment outcome, and discuss how advances in conceptual frameworks of brain-behavior relationships are fueling the development of novel AUD interventions that include techniques for cognitive remediation. Emerging evidence suggests that such interventions can be effective in promoting cognitive recovery in persons with AUD and other substance use disorders, and potentially increasing the efficacy of AUD treatments. Finally, translational approaches based on cognitive science, neurophysiology, and neuroscience research are considered as promising future directions for effective treatment development that includes cognitive rehabilitation.