Differential brain activity in alcoholics and social drinkers to alcohol cues: relationship to craving

Comorbidity of ADHD and Substance Use Disorder (SUD): a neuroimaging perspective

INTRODUCTION

ADHD has a high comorbidity with substance use disorders (SUD). Both diseases have profound social, psychological, and economic consequences and are therefore highly relevant for health systems. The high comorbidity indicates some shared underlying neurobiological substrates. Knowing these substrates may increase the understanding of the disease and help identify therapeutic processes.

METHOD

Neuroimaging studies of ADHD were reviewed and similarities with SUD identified. For this a PubMed research was conducted with the search terms ADHD, SUD, MRI or positron emission tomography (PET) or spectroscopy or imaging.

RESULTS

Similarities were found, in both PET and fMRI studies, between patients with ADHD and those with addiction-related craving. Results from structural MRI and MR spectroscopy do not support a common pathophysiological background, probably because of the lack of studies on craving.

DISCUSSION

ADHD and SUD-related craving share some neurobiological similarities. One reason may be that patients with addiction show more craving when they also suffer from ADHD. The present review thus supports the conclusion from an earlier meta-analysis of clinical studies which found that adequate treatment of ADHD reduces craving and relapse into substance use.

fMRI BOLD response in high-risk college students (Part 1): during exposure to alcohol, marijuana, polydrug and emotional picture cues

AIM

This functional magnetic resonance imaging (fMRI) study examined reactivity to alcohol, polydrug, marijuana and emotional picture cues in students who were referred to a college alcohol and drug assistance program.

METHODS

The fMRI data of 10 participants (5 females; 5 males) were collected while they viewed standardized emotional and appetitive cues.

RESULTS

Positive and negative emotional cues produced greater activity than neutral cues in the expected brain areas. Compared with neutral cues, alcohol cues produced greater brain activation in the right insula, left anterior cingulate, left caudate and left prefrontal cortex (Z = 2.01, 1.86, 1.82, 1.81, respectively; P < 0.05). Drug cues produced significantly greater left prefrontal activity compared with neutral cues, with polydrug cues activating the right insula and marijuana cues activating left anterior cingulate.

CONCLUSIONS

Students at-risk for alcohol abuse showed neural reactivity to alcohol cues in four brain regions, which is consistent with their greater use of alcohol. Insula activation to appetitive cues may be an early marker of risk for progression to alcohol/drug abuse.

fMRI BOLD response of high-risk college students (Part 2): during memory priming of alcohol, marijuana and polydrug picture cues

AIMS

This study examined brain activity using functional magnetic resonance imaging (fMRI) and reaction time (RT) during an implicit repetition priming memory task involving alcohol, polydrug, marijuana and emotional picture cues.

METHODS

Participants were 5 male and 5 female high-risk college students who had just participated in a cue exposure study (Ray et al., this issue). fMRI and RT data were collected while participants made decisions about previously seen and new picture cues.

RESULTS

Both behavioral RT and brain imaging data revealed strong memory priming for drug and alcohol cues. Neurologically, a repetition priming effect (suppression in neural activity for repeated cues) was observed in response to alcohol cues in the left prefrontal, bilateral occipital, and bilateral occipitotemporal regions, as well as right insula and right precuneus (Z ranged from 3.03 to 3.31 P < 0.05). Polydrug cues elicited priming in the occipital and temporal areas, and marijuana cues in the occipital area.

CONCLUSIONS

Prefrontal and insular cortex involvement both in reactivity to alcohol cues (Ray et al., this issue) and subsequent implicit memory processing of these cues, as found in this study, suggests their potential role in the maintenance of high-risk alcohol use behaviors.

The effect of aripiprazole on cue-induced brain activation and drinking parameters in alcoholics

Because the effects of alcohol and its environmental cues on brain dopamine have been implicated in the maintenance of heavy drinking, drugs that modify dopamine might be useful in reducing drinking or promoting abstinence. The goal of the current study was to use an established brain imaging paradigm to explore the effect of aripiprazole (final dose 15 mg over a 14-day period), a dopamine stabilizer medication, on alcohol cue-induced brain activation and drinking in alcoholics. Non-treatment-seeking alcoholics were randomly assigned aripiprazole (n = 14) or identical placebo (n = 16) and reported their alcohol use while taking study medication for 14 days before an alcohol cue-induced brain functional magnetic resonance imaging study. In a Philips 3.0-T magnetic resonance imaging scanner, subjects were given a sip of alcohol before viewing a randomized presentation alcoholic- and nonalcoholic-beverage photographs while subjects rated their urge to drink. During photograph presentation, changes in regional brain activity were measured, and differences between viewing alcoholic beverage and nonalcoholic beverages were compared within and between groups. Brain activity analysis revealed increased activation for placebo-treated subjects in the right ventral striatum (P < 0.005; threshold 15 voxels), while there was a blunting of activation in this area in the aripiprazole-treated subjects. Aripiprazole-treated subjects, compared with placebo-treated subjects, also had significantly less heavy drinking during the 14-day medication period. The study provides both novel and valuable information regarding the effect of aripiprazole on cue-induced brain activation and voluntary drinking during treatment.

Harsh corporal punishment is associated with increased T2 relaxation time in dopamine-rich regions

Harsh corporal punishment (HCP) was defined as frequent parental administration of corporal punishment (CP) for discipline, with occasional use of objects such as straps, or paddles. CP is linked to increased risk for depression and substance abuse. We examine whether long-term exposure to HCP acts as sub-traumatic stressor that contributes to brain alterations, particularly in dopaminergic pathways, which may mediate their increased vulnerability to drug and alcohol abuse. Nineteen young adults who experienced early HCP but no other forms of maltreatment and twenty-three comparable controls were studied. T2 relaxation time (T2-RT) measurements were performed with an echo planar imaging TE stepping technique and T2 maps were calculated and analyzed voxel-by-voxel to locate regional T2-RT differences between groups. Previous studies indicated that T2-RT provides an indirect index of resting cerebral blood volume. Region of interest (ROI) analyses were also conducted in caudate, putamen, nucleus accumbens, anterior cingulate cortex, dorsolateral prefrontal cortex, thalamus, globus pallidus and cerebellar hemispheres. Voxel-based relaxometry showed that HCP was associated with increased T2-RT in right caudate and putamen. ROI analyses also revealed increased T2-RT in dorsolateral prefrontal cortex, substantia nigra, thalamus and accumbens but not globus pallidus or cerebellum. There were significant associations between T2-RT measures in dopamine target regions and use of drugs and alcohol, and memory performance. Alteration in the paramagnetic or hemodynamic properties of dopaminergic cell body and projection regions were observed in subjects with HCP, and these findings may relate to their increased risk for drug and alcohol abuse.

A potential role for adiponectin receptor 2 (AdipoR2) in the regulation of alcohol intake

The anterior cingulate cortex (ACC) has been implicated in alcohol and drug addiction. We recently identified the small G protein K-ras as an alcohol-regulated gene in the ACC by gene expression analysis. We show here that the adiponectin receptor 2 (AdipoR2) was differentially regulated by alcohol in the ACC in a K-ras-dependent manner. Additionally, withdrawal-associated increased drinking was attenuated in AdipoR2 null mice. Intracellular recordings revealed that adiponectin increased the excitability of ACC neurons and that this effect was more pronounced during alcohol withdrawal, suggesting that AdipoR2 signaling may contribute to increased ACC activity. Altogether, the data implicate K-ras-regulated pathways involving AdipoR2 in the cellular and behavioral actions of alcohol that may contribute to overactivity of the ACC during withdrawal and excessive alcohol drinking.

The insula and drug addiction: an interoceptive view of pleasure, urges, and decision-making

We have recently shown that damage to the insula leads to a profound disruption of addiction to cigarette smoking (Naqvi et al., Science 315:531-534, 2007). Yet, there is little understanding of why the insula should play such an important role in an addictive behavior. A broad literature (much of it reviewed in this issue) has addressed the role of the insula in processes related to conscious interoception, emotional experience, and decision-making. Here, we review evidence for the role of the insula in drug addiction, and propose a novel theoretical framework for addiction in which the insula represents the interoceptive effects of drug taking, making this information available to conscious awareness, memory and executive functions. A central theme of this framework is that a primary goal for the addicted individual is to obtain the effects of the drug use ritual upon the body, and representations of this goal in interoceptive terms by the insula contribute to how addicted individuals feel, remember, and decide about taking drugs. This makes drug addiction like naturally motivated behaviors, such as eating and sex, for which an embodied ritual is the primary goal.

Genome-wide gene expression analysis identifies K-ras as a regulator of alcohol intake

Adaptations in the anterior cingulate cortex (ACC) have been implicated in alcohol and drug addiction. To identify genes that may contribute to excessive drinking, here we performed microarray analyses in laser microdissected rat ACC after a single or repeated administration of an intoxicating dose of alcohol (3 g/kg). Expression of the small G protein K-ras was differentially regulated following both single and repeated alcohol administration. We also observed that voluntary alcohol intake in K-ras heterozygous null mice (K-ras(+/-)) did not increase after withdrawal from repeated cycles of intermittent ethanol vapor exposure, unlike in their wild-type littermates. To identify K-ras regulated pathways, we then profiled gene expression in the ACC of K-ras(+/-), heterozygous null mice for the K-ras negative regulator Nf1 (Nf1(+/-)) and wild-type mice following repeated administration of an intoxicating dose of alcohol. Pathway analysis showed that alcohol differentially affected various pathways in a K-ras dependent manner - some of which previously shown to be regulated by alcohol - including the insulin/PI3K pathway, the NF-kappaB, the phosphodiesterases (PDEs) pathway, the Jak/Stat and the adipokine signaling pathways. Altogether, the data implicate K-ras-regulated pathways in the regulation of excessive alcohol drinking after a history of dependence.

Altered regional cerebral glucose metabolism in internet game overusers: a 18F-fluorodeoxyglucose positron emission tomography study

INTRODUCTION

Internet game overuse is an emerging disorder and features diminished impulse control and poor reward-processing. In an attempt to understand the neurobiological bases of Internet game overuse, we investigated the differences in regional cerebral glucose metabolism at resting state between young individuals with Internet game overuse and those with normal use using 18F-fluorodeoxyglucose positron emission tomography study.

METHODS

Twenty right-handed male participants (9 normal users: 24.7+/-2.4 years of age, 11 overusers: 23.5+/-2.9 years of age) participated. A trait measure of impulsivity was also completed after scanning.

RESULTS

Internet game overusers showed greater impulsiveness than the normal users and there was a positive correlation between the severity of Internet game overuse and impulsiveness. Imaging data showed that the overusers had increased glucose metabolism in the right middle orbitofrontal gyrus, left caudate nucleus, and right insula, and decreased metabolism in the bilateral postcentral gyrus, left precentral gyrus, and bilateral occipital regions compared to normal users.

CONCLUSION

Internet game overuse may be associated with abnormal neurobiological mechanisms in the orbitofrontal cortex, striatum, and sensory regions, which are implicated in impulse control, reward processing, and somatic representation of previous experiences. Our results support the idea that Internet game overuse shares psychological and neural mechanisms with other types of impulse control disorders and substance/non-substance-related addiction.

Alcohol cue reactivity task development

BACKGROUND

The physiological and cognitive reactions provoked by alcohol cues, as compared to non-alcohol cues, can predict future drinking. Alcohol cue reactivity tasks have been developed; however, most were created for use with alcohol use disordered individuals and utilize limited or only partially standardized stimuli. This project systematically created an alcohol cue reactivity task for studies with non-drinkers, using well-characterized stimuli.

OBJECTIVES

We comprehensively standardized 60 alcohol and 60 non-alcohol beverage pictures using ratings from young non-drinkers (N=82) on affective and perceptual features.

RESULTS

A statistical matching approach yielded 26 matched alcohol-non-alcohol picture pairs matched on valence, arousal, image complexity, brightness, and hue. The task was piloted and further refined to 22 picture pairs. An 8-minute, 32-second event-related task was created using a random stimulus function for optimized condition timing and systematic presentation of the images.

CONCLUSIONS

The long-term objectives of this project are to utilize this task with non-drinking youth to investigate how reactivity to alcohol stimuli may predict alcohol use initiation and escalation, to help identify the role of exposure to alcohol stimuli on the subsequent development of alcohol-related problems.

Family history of alcoholism mediates the frontal response to alcoholic drink odors and alcohol in at-risk drinkers

Although a family history of alcoholism is the strongest risk factor for developing alcohol dependence, there are few studies of the association between familial alcoholism and the human brain's reward system activity. We used functional magnetic resonance imaging (fMRI) to determine how family history affects the brain's response to subjects' preferred alcoholic drink odors (AO) as compared to appetitive control odors (ApCO). Fourteen non-dependent heavy drinkers (HD) who were family history positive (FHP) participated, as did 12 HD who were family history negative (FHN). Subjects were imaged under both alcohol intoxication and placebo, using intravenous infusion and pharmacokinetic modeling to target a blood alcohol level of 50 mg%. Under placebo, HD-FHP had a larger medial frontal [AO>ApCO] effect than did HD-FHN. Alcohol intoxication dampened this response in the HD-FHP but potentiated it in the HD-FHN. This suggests that a family history of alcoholism and brain exposure to alcohol interact in heavy drinkers to differentially affect how the brain responds to alcohol cues.

Ethanol self-administration modulation of NMDA receptor subunit and related synaptic protein mRNA expression in prefrontal cortical fields in cynomolgus monkeys

BACKGROUND

Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication, and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in the alcohol-addicted state.

METHODS AND RESULTS

The effects of chronic ethanol self-administration on glutamate receptor ionotropic NMDA (GRIN), as well as GRIN1 splice variant mRNA expression was studied in the orbitofrontal cortex (OFC; Area 13), dorsolateral prefrontal cortex (DLPFC; Area 46) and anterior cingulate cortex (ACC; Area 24) of male cynomolgus monkeys. Chronic ethanol self-administration resulted in significant changes in the expression of NMDA subunit mRNA expression in the DLPFC and OFC, but not the ACC. In DLPFC, the overall expression of NMDA subunits was significantly decreased in ethanol treated monkeys. Slight but significant changes were observed for synaptic associated protein 102 kD (SAP102) and neuronal nitric oxide synthase (nNOS) mRNAs. In OFC, the NMDAR1 variant GRIN1-1 was reduced while GRIN1-2 was increased. Furthermore, no significant changes in GFAP protein levels were observed in either the DLPFC or OFC.

CONCLUSION

Results from these studies provide the first demonstration of posttranscriptional regulation of iGluR subunits in the primate brain following long-term ethanol self-administration. Furthermore, changes in these transcripts do not appear to reflect changes in glial activation or loss. Further studies examining the expression and cellular localization of subunit proteins and receptor pharmacology would shed more light on the findings reported here.

Substance abuse is a disease of the human brain: focus on alcohol

Alcohol and substance abuse are prevalent in our society. Advances in neuroscience have led to a clearer understanding of the effects of abused substances on the brain. Clues are now available regarding how a person goes from a "user" to being addicted based on brain chemistry, anatomy, and genetic risk. During this process the person loses at least partial, if not complete, control, over their compulsive substance use. This article attempts to put modern notions of alcohol and substance abuse and dependency into a societal and cultural context with the hope of reducing the stigma of this illness while shifting the focus a bit more away from criminal solutions to those offered by health care and treatment options.

Exploring the relationship between depressive and anxiety symptoms and neuronal response to alcohol cues

BACKGROUND

Depressive and anxiety symptoms tend to co-occur with heavy drinking. Specifically, their presence may exacerbate the severity and intractability of heavy drinking. Similarly, heavy drinking may increase the risk for and experience of depressive and anxiety symptoms. Although depressive and anxiety symptoms have been significantly correlated with alcohol craving in cue-exposure paradigms, physiological responses have not always mapped onto emotional responses. Therefore, this study sought to examine the role of depressive and anxiety symptoms using a more basic science approach, through examining functional brain changes.

METHODS

Seventy nontreatment seeking, heavy drinking adults were recruited through a college campus (n = 45 men; mean age = 22.8). They completed measures of drinking, smoking, depressive symptoms, anxiety symptoms, and a functional magnetic resonance imaging (fMRI) cue-exposure paradigm.

RESULTS

As hypothesized, depressive symptoms were positively correlated with activation during the alcohol (vs. appetitive control) cue in the insula, cingulate, ventral tegmentum, striatum, and thalamus (cluster-corrected p < 0.05, z = 2.3). Similarly, anxiety symptoms were positively correlated with activation during the alcohol (vs. appetitive control) cue in the striatum, thalamus, insula, and inferior frontal, mid-frontal, and cingulate gyri (cluster-corrected p < 0.05, z = 2.3).

CONCLUSIONS

Significant correlations were found between depressive symptoms, anxiety symptoms, and differential brain activation in response to an alcohol versus an appetitive control cue in an fMRI paradigm. Moreover, the pattern of activation mapped onto expected regions. This study strongly supports the posited relationships between depressive symptoms, anxiety symptoms, and differential brain activation in an alcohol cue-exposure paradigm with a sample of heavy drinking adults.

Temporal decision-making: insights from cognitive neuroscience

Decisions frequently have consequences that play out over time and these temporal factors can exert strong influences on behavior. For example, decision-makers exhibit delay discounting, behaving as though immediately consumable goods are more valuable than those available only after some delay. With the use of functional magnetic resonance imaging, we are now beginning to characterize the physiological bases of such behavior in humans and to link work on this topic from neuroscience, psychology, and economics. Here we review recent neurocognitive investigations of temporal decision-making and outline the theoretical picture that is beginning to take shape. Taken as a whole, this body of work illustrates the progress made in understanding temporal choice behavior. However, we also note several questions that remain unresolved and areas where future work is needed.

Ventral striatal activation during reward anticipation correlates with impulsivity in alcoholics

BACKGROUND

Alcohol dependence is often associated with impulsivity, which may be correlated with dysfunction of the brain reward system. We explored whether functional brain activation during anticipation of incentive stimuli is associated with impulsiveness in detoxified alcoholics and healthy control subjects.

METHODS

Nineteen detoxified male alcoholics and 19 age-matched healthy men participated in a functional magnetic resonance imaging (fMRI) study using a monetary incentive delay (MID) task, in which visual cues predicted that a rapid response to a subsequent target stimulus would either result in monetary gain, avoidance of monetary loss, or no consequence. Impulsivity was assessed with the Barratt Impulsiveness Scale-Version 10 (BIS-10).

RESULTS

Detoxified alcoholics showed reduced activation of the ventral striatum during anticipation of monetary gain relative to healthy control subjects. Low activation of the ventral striatum and anterior cingulate during gain anticipation was correlated with high impulsivity only in alcoholics, not in control subjects.

CONCLUSIONS

This study suggests that reduced ventral striatal recruitment during anticipation of conventional rewards in alcoholics may be related to their increased impulsivity and indicate possibilities for enhanced treatment approaches in alcohol dependence.

Counteracting incentive sensitization in severe alcohol dependence using deep brain stimulation of the nucleus accumbens: clinical and basic science aspects

The ventral striatum/nucleus accumbens (NAcc) has been implicated in the craving for drugs and alcohol which is a major reason for relapse of addicted people. Craving might be induced by drug-related cues. This suggests that disruption of craving-related neural activity in the NAcc may significantly reduce craving in alcohol-dependent patients. Here we report on preliminary clinical and neurophysiological evidence in three male patients who were treated with high frequency deep brain stimulation of the NAcc bilaterally. All three had been alcohol-dependent for many years, unable to abstain from drinking, and had experienced repeated relapses prior to the stimulation. After the operation, craving was greatly reduced and all three patients were able to abstain from drinking for extended periods of time. Immediately after the operation but prior to connection of the stimulation electrodes to the stimulator, local field potentials were obtained from the externalized cables in two patients while they performed cognitive tasks addressing action monitoring and incentive salience of drug-related cues. LFPs in the action monitoring task provided further evidence for a role of the NAcc in goal-directed behaviors. Importantly, alcohol-related cue stimuli in the incentive salience task modulated LFPs even though these cues were presented outside of the attentional focus. This implies that cue-related craving involves the NAcc and is highly automatic.

Cognitive processes in alcohol binges: a review and research agenda

Alcohol abuse is associated with a cluster of long-term changes in cognitive processes, as predicted by contemporary models of addiction. In this paper we review evidence which suggests that similar changes may occur during an alcohol binge, and as such they may play an important role in explaining the loss of control over alcohol consumption that occurs during alcohol binges. As a consequence of both acute alcohol intoxication (alcohol 'priming' effects) and exposure to environmental alcohol-related cues, we suggest that a number of changes in cognitive processes are likely. These include increased subjective craving for alcohol, increased positive and arousing outcome expectancies and implicit associations for alcohol use, increased attentional bias for alcohol-related cues, increased action tendencies to approach alcohol, increased impulsive decision-making, and impaired inhibitory control over drives and behaviour. Potential reciprocal relationships between these different aspects of cognition during an alcohol binge are discussed. Finally, we discuss the relationship between the current model and existing models of cognitive processes in substance abuse, and we speculate on the implications of the model for the reduction binge drinking and its consequences.

Emphasizing interpersonal factors: an extension of the Witkiewitz and Marlatt relapse model

AIM

Recently, Witkiewitz & Marlatt reformulated the Marlatt & Gordon relapse model to account for current research findings. The present paper aims to extend this model further to incorporate social variables more fully.

METHODS

The social-factors and alcohol-relapse literatures were reviewed within the framework of the reformulated relapse model.

RESULTS

The literature review found that the number of social network members, investment of the individual in the social network, levels of general and alcohol-specific support available within the social network and specific behaviors of network members all predict drinking outcomes. However, little is known about the mechanisms by which these social variables influence outcomes. The authors postulate that social variables influence outcomes by affecting intra-individual factors central to the reformulated relapse prevention model, including processes (e.g. self-efficacy, outcome expectancies, craving, motivation, negative affective states) and behaviors (e.g. coping and substance use). The authors suggest specific hypotheses and discuss methods that can be used to study the impact of social factors on the intra-individual phenomena that contribute to relapse.

CONCLUSION

The proposed extension of the relapse model provides testable hypotheses that may guide future alcohol-relapse research.

Marijuana craving in the brain

Craving is one of the primary behavioral components of drug addiction, and cue-elicited craving is an especially powerful form of this construct. While cue-elicited craving and its underlying neurobiological mechanisms have been extensively studied with respect to alcohol and other drugs of abuse, the same cannot be said for marijuana. Cue-elicited craving for other drugs of abuse is associated with increased activity in a number of brain areas, particularly the reward pathway. This study used functional magnetic resonance imaging (fMRI) to examine cue-elicited craving for marijuana. Thirty-eight regular marijuana users abstained from use for 72 h and were presented with tactile marijuana-related and neutral cues while undergoing a fMRI scan. Several structures in the reward pathway, including the ventral tegmental area, thalamus, anterior cingulate, insula, and amygdala, demonstrated greater blood oxygen level dependent (BOLD) activation in response to the marijuana cue as compared with the neutral cue. These regions underlie motivated behavior and the attribution of incentive salience. Activation of the orbitofrontal cortex and nucleus accumbens was also positively correlated with problems related to marijuana use, such that greater BOLD activation was associated with greater number of items on a marijuana problem scale. Thus, cue-elicited craving for marijuana activates the reward neurocircuitry associated with the neuropathology of addiction, and the magnitude of activation of these structures is associated with severity of cannabis-related problems. These findings may inform the development of treatment strategies for cannabis dependence.

Decreased neural activity in reward circuitry during personal reference in abstinent alcoholics--a fMRI study

Two of the most striking features in alcoholism are the irresistible craving for alcohol and the proceeding neglect of other activities and pleasures that were formerly relevant. Craving has been investigated extensively and is commonly due to a dysfunctional reward system. The neural basis of the neglect of self-relevant interests, which can be described as altered personal reference, and its association to the reward system, however, remains unclear. Using fMRI, we investigated neural activity during a paradigm that tested for both reward and personal reference with regard to the same stimuli, i.e., alcoholic and nonalcoholic pictures, in healthy subjects and abstinent alcoholic patients. Alcoholic patients showed slightly reduced signal changes in the brain stem adjacent to ventral tegmental area (VTA) and in the ventromedial prefrontal cortex (VMPFC) during the reward task, while we found no alterations in the right and left ventral striatum (VS). The same regions (VS, VTA, and VMPFC), however, showed reduced signal changes during personal reference with lack of neural differentiation between high and low referenced stimuli in alcoholic patients. In summary, we demonstrate for the first time neurophysiological alterations in reward circuitry during personal reference in alcoholic patients. Our results underline the important role of the reward circuitry during personal reference in the pathophysiology of alcohol addiction.

Clinical and laboratory assessment of the subjective experience of drug craving

Measures of subjective drug craving - often defined as the experience of an intense or compelling urge or desire - may be used to predict relapse, evaluate psychological and pharmacological treatments, and test theories of addiction and craving. This review summarizes both direct self-report questionnaires and indirect behavioral, physiological and reaction time measures designed to assess craving for alcohol, amphetamines, cocaine, heroin, marijuana, and tobacco. Multi-item questionnaires have typically been based on one of four underlying conceptualizations of addiction or craving (obsessive-compulsive, approach-avoidance, multi-dimensional, intensity-frequency-duration). Most multi-item self-report questionnaires have high internal consistency, correlate significantly with single-item craving ratings, and demonstrate several aspects of construct validity. Proposed indirect or proxy measures of craving include drug dreams, speed of drug consumption, willingness to work for drug access, selection of monetary rewards over drug access, psychophysiological reactivity, and attentional bias to drug cues. These proxy measures of craving are presumed to obviate self-report biases, to be less subject to conscious self-control, and to reflect craving which the person may not be able to articulate; however, there have been too few demonstrations of their validity and they have too many practical limitations to supplant self-report measures of craving at this time.

Alcoholism: A Systems Approach From Molecular Physiology to Addictive Behavior

Alcohol consumption is an integral part of daily life in many societies. The benefits associated with the production, sale, and use of alcoholic beverages come at an enormous cost to these societies. The World Health Organization ranks alcohol as one of the primary causes of the global burden of disease in industrialized countries. Alcohol-related diseases, especially alcoholism, are the result of cumulative responses to alcohol exposure, the genetic make-up of an individual, and the environmental perturbations over time. This complex gene × environment interaction, which has to be seen in a life-span perspective, leads to a large heterogeneity among alcohol-dependent patients, in terms of both the symptom dimensions and the severity of this disorder. Therefore, a reductionistic approach is not very practical if a better understanding of the pathological processes leading to an addictive behavior is to be achieved. Instead, a systems-oriented perspective in which the interactions and dynamics of all endogenous and environmental factors involved are centrally integrated, will lead to further progress in alcohol research. This review adheres to a systems biology perspective such that the interaction of alcohol with primary and secondary targets within the brain is described in relation to the behavioral consequences. As a result of the interaction of alcohol with these targets, alterations in gene expression and synaptic plasticity take place that lead to long-lasting alteration in neuronal network activity. As a subsequent consequence, alcohol-seeking responses ensue that can finally lead via complex environmental interactions to an addictive behavior.

Brain activities associated with gaming urge of online gaming addiction

The aim of this study was to identify the neural substrates of online gaming addiction through evaluation of the brain areas associated with the cue-induced gaming urge. Ten participants with online gaming addiction and 10 control subjects without online gaming addiction were tested. They were presented with gaming pictures and the paired mosaic pictures while undergoing functional magnetic resonance imaging (fMRI) scanning. The contrast in blood-oxygen-level dependent (BOLD) signals when viewing gaming pictures and when viewing mosaic pictures was calculated with the SPM2 software to evaluate the brain activations. Right orbitofrontal cortex, right nucleus accumbens, bilateral anterior cingulate and medial frontal cortex, right dorsolateral prefrontal cortex, and right caudate nucleus were activated in the addicted group in contrast to the control group. The activation of the region-of-interest (ROI) defined by the above brain areas was positively correlated with self-reported gaming urge and recalling of gaming experience provoked by the WOW pictures. The results demonstrate that the neural substrate of cue-induced gaming urge/craving in online gaming addiction is similar to that of the cue-induced craving in substance dependence. The above-mentioned brain regions have been reported to contribute to the craving in substance dependence, and here we show that the same areas were involved in online gaming urge/craving. Thus, the results suggest that the gaming urge/craving in online gaming addiction and craving in substance dependence might share the same neurobiological mechanism.

The DRD4 exon 3 VNTR polymorphism and addiction-related phenotypes: a review

In addition to the large literatures on associations of the DRD4 VNTR polymorphism with ADHD and personality traits, there is an emerging literature linking this variant to addiction and addiction-related phenotypes. When only diagnosis-based studies are considered, an inconsistent picture emerges raising doubts as to the relevance of this polymorphism to addiction. However the use of multiple levels of analysis in examining the importance of this polymorphism has raised the possibility of an urge-related "intermediate phenotype" that puts one at risk for developing addiction but may not be found in all persons with an addiction diagnosis. From cellular assays through neuroimaging and behavioral phenotypes, these studies highlight the power of the "intermediate phenotype" approach and suggest a possible explanation of the mixed findings when diagnosis is used as the phenotype. Strengths and weaknesses of alternative DRD4 VNTR genotype grouping strategies are discussed. In sum, converging evidence across multiple methodologies supports the possibility of a robust relationship between the DRD4 exon 3 VNTR polymorphism and urge for addictive substances.

Altered impulse control in alcohol dependence: neural measures of stop signal performance

BACKGROUND

Altered impulse control has been implicated in the shaping of habitual alcohol use and eventual alcohol dependence. We sought to identify the neural correlates of altered impulse control in 24 abstinent patients with alcohol dependence (PAD), as compared to 24 demographics matched healthy control subjects (HC). In particular, we examined the processes of risk taking and cognitive control as the neural endophenotypes of alcohol dependence.

METHODS

To this end, functional magnetic resonance imaging (fMRI) was conducted during a stop signal task (SST), in which a procedure was used to elicit errors in the participants. The paradigm allowed trial-by-trial evaluation of response inhibition, error processing, and post-error behavioral adjustment. Furthermore, by imposing on the subjects to be both fast and accurate, the SST also introduced a distinct element of risk, which participants may or may not avert during the task. Brain imaging data were analyzed with Statistical Parametric Mapping in covariance analyses accounting for group disparity in general performance.

RESULTS

The results showed that, compared to HC, PAD demonstrated longer go trial reaction time (RT) and higher stop success rate (SS%). HC and PAD were indistinguishable in stop signal reaction time (SSRT) and post-error slowing (PES). In a covariance analysis accounting for go trial RT and SS%, HC showed greater activity in the left dorsolateral prefrontal cortex than PAD, when subjects with short and long SSRT were contrasted. By comparing PAD and HC directly during stop errors (SE), as contrasted with SS, we observed greater activity in PAD in bilateral visual and frontal cortices. Compared to HC, PAD showed less activation of the right dorsolateral prefrontal cortex during PES, an index of post-error behavioral adjustment. Furthermore, PAD who showed higher alcohol urge at the time of the fMRI were particularly impaired in dorsolateral prefrontal activation, as compared to those with lower alcohol urge. Finally, compared to HC subjects, PAD showed less activity in cortical and subcortical structures including putamen, insula, and amygdala during risk-taking decisions in the SST.

CONCLUSION

These preliminary results provided evidence for altered neural processing during impulse control in PAD. These findings may provide a useful neural signature in the evaluation of treatment outcomes and development of novel pharmacotherapy for alcohol dependence.

Identifying the neural circuitry of alcohol craving and relapse vulnerability

With no further intervention, relapse rates in detoxified alcoholics are high and usually exceed 80% of all detoxified patients. It has been suggested that stress and exposure to priming doses of alcohol and to alcohol-associated stimuli (cues) contribute to the relapse risk after detoxification. This article focuses on neuronal correlates of cue responses in detoxified alcoholics. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) can be associated with alcohol craving and functional brain activation in neuronal systems that process attentional relevant stimuli, reward expectancy and experience. Increased functional brain activation elicited by such alcohol-associated cues predicted an increased relapse risk, whereas high brain activity elicited by affectively positive stimuli may represent a protective factor and was correlated with a decreased prospective relapse risk. These findings are discussed with respect to psychotherapeutic and pharmacological treatment options.

The hidden island of addiction: the insula

Most prior research on the neurobiology of addiction has focused on the role of subcortical systems, such as the amygdala, the ventral striatum and mesolimbic dopamine system, in promoting the motivation to seek drugs. Recent evidence indicates that a largely overlooked structure, the insula, plays a crucial part in conscious urges to take drugs. The insula has been highlighted as a region that integrates interoceptive (i.e. bodily) states into conscious feelings and into decision-making processes that involve uncertain risk and reward. Here, we propose a model in which the processing of the interoceptive effects of drug use by the insula contributes to conscious drug urges and to decision-making processes that precipitate relapse.

Effect of naltrexone during extinction of alcohol-reinforced responding and during repeated cue-conditioned reinstatement sessions in a cue exposure style treatment

The ability of alcohol-related cues to promote craving can be attenuated independently by giving the opioid antagonist naltrexone (NTX) or by subjecting alcohol-dependent patients to a cue exposure treatment. The effects of cue exposure treatment may be enhanced if conducted in the presence of NTX. The purpose of these experiments was to determine if NTX given during extinction of responding for alcohol in rats would alter cue-conditioned reinstatement of responding and to determine if NTX, paired with repeated cue-conditioned reinstatement, would reduce subsequent cue-conditioned reinstatement or reacquisition of self-administration in the absence of NTX. Rats lever pressed for alcohol in the presence of an olfactory cue. Visual and auditory stimuli were presented during alcohol delivery. In the first experiment, rats were injected with saline or 3mg/kg NTX prior to extinction sessions followed by cue-conditioned reinstatement tests. In the second experiment, extinction was followed by cue-conditioned reinstatement sessions presented twice per week. The rats received saline or NTX (3 and 10mg/kg) prior to several sessions. All rats received reinstatement tests with and without a pretreatment of NTX followed by reacquisition of alcohol self-administration. NTX had no effect on responding during extinction or on subsequent cue-conditioned reinstatement. Only 10mg/kg NTX reduced responding during the twice weekly reinstatement sessions. The twice weekly NTX treatment had no effect on subsequent cue-conditioned reinstatement in the absence of NTX. Reacquisition of responding for alcohol was reduced in the group receiving saline during repeated reinstatement sessions, whereas this effect was blocked in the NTX group. These findings support the notion that NTX given during a brief abstinence period (i.e., extinction) has minimal effects on future sensitivity to alcohol cues and alcohol consumption. NTX given during the repeated alcohol cue exposure does not alter the subsequent incentive value of alcohol cues in the absence of NTX or enhance the beneficial effects of cue exposure treatment.

When what you see isn't what you get: alcohol cues, alcohol administration, prediction error, and human striatal dopamine

BACKGROUND

The mesolimbic dopamine (DA) system is implicated in the development and maintenance of alcohol drinking; however, the exact mechanisms by which DA regulates human alcohol consumption are unclear. This study assessed the distinct effects of alcohol-related cues and alcohol administration on striatal DA release in healthy humans.

METHODS

Subjects underwent 3 PET scans with [(11)C]raclopride (RAC). Subjects were informed that they would receive either an IV Ringer's lactate infusion or an alcohol (EtOH) infusion during scanning, with naturalistic visual and olfactory cues indicating which infusion would occur. Scans were acquired in the following sequence: (1) Baseline Scan: Neutral cues predicting a Ringer's lactate infusion, (2) CUES Scan: Alcohol-related cues predicting alcohol infusion in a Ringer's lactate solution, but with alcohol infusion after scanning to isolate the effects of cues, and (3) EtOH Scan: Neutral cues predicting Ringer's, but with alcohol infusion during scanning (to isolate the effects of alcohol without confounding expectation or craving).

RESULTS

Relative to baseline, striatal DA concentration decreased during CUES, but increased during EtOH.

CONCLUSION

While the results appear inconsistent with some animal experiments showing dopaminergic responses to alcohol's conditioned cues, they can be understood in the context of the hypothesized role of the striatum in reward prediction error, and of animal studies showing that midbrain dopamine neurons decrease and increase firing rates during negative and positive prediction errors, respectively. We believe that our data are the first in humans to demonstrate such changes in striatal DA during reward prediction error.

Differential neural response to alcohol priming and alcohol taste cues is associated with DRD4 VNTR and OPRM1 genotypes

BACKGROUND

Studies suggest that polymorphisms in the D4 dopamine receptor (DRD4) and opioid receptor, mu 1 (OPRM1) genes are involved in differential response to the effects of alcohol and to alcohol cues. However, to date, the mechanisms that underlie these differences remain largely unknown.

METHODS

Using functional magnetic resonance imaging, hemodynamic response in mesocorticolimbic structures after exposure to alcohol tastes was contrasted with a control taste and compared between DRD4 variable number of tandem repeats (VNTR) genotypes and OPRM1 A118G genotypes. Additionally, the effects of a priming dose of alcohol on this response were examined.

RESULTS

The results indicated that DRD4 VNTR >7 repeat individuals (DRD4.L) had significantly greater response to alcohol cues in the orbitofrontal cortex, anterior cingulate gyrus, and striatum compared with individuals with <7 repeats (DRD4.S) prior to a priming dose of alcohol (p < 0.05), but not after a priming dose. In the OPRM1 comparisons, results showed that individuals with at least 1 copy of the OPRM1 + 118 G allele had greater hemodynamic response in mesocorticolimbic areas both before and after priming compared with those who were homozygous for the OPRM1 + 118 A allele. For the DRD4.L and OPRM1 + 118 G groups, brain response in the striatum was highly correlated with measures of alcohol use and behavior such that greater activity corresponded with greater frequency and quantity of alcohol use.

CONCLUSIONS

The DRD4 VNTR and OPRM1 A118G polymorphisms are associated with functional neural changes in mesocorticolimbic structures after exposure to alcohol cues. This provides evidence for the contributions of the DRD4 and OPRM1 genes in modulating neural activity in structures that are involved in the motivation to drink.

Alcohol sensitizes cerebral responses to the odors of alcoholic drinks: an fMRI study

BACKGROUND

Small, priming doses of alcohol enhance desire to drink, and thus play a role in the loss of control of alcohol consumption. Using functional magnetic resonance imaging (fMRI), we previously showed that alcoholic drink odors (AO; subjects' drinks of choice) induce greater nucleus accumbens (NAc) activity than non-appetitive odors (NApO; grass, leather) in subjects at risk for alcoholism. Here we hypothesized that priming exposure to alcohol would enhance responses to AO in the NAc and orbitofrontal cortex in comparison to NApO (grass, leather) and to the appetitive control odors (ApCO) of chocolate and grape.

METHODS

Ten hazardous drinkers (mean age = 22.7; SD = 2.9, average drinks per drinking day = 5.9, SD = 2.3; drinking days/90 days = 50.4, SD = 13.7) were scanned on a 1.5 T GE Signa MR scanner during intravenous infusion of lactated Ringer's or 6% ethanol in lactated Ringer's that was pharmacokinetically modeled to achieve a constant breath alcohol concentration (BrAC) of 50 mg% throughout imaging. During scanning, subjects sniffed AO, NApO, and ApCO.

RESULTS

Alcohol infusion enhanced the contrast between AO and NApO in the NAc, and in orbitofrontal, medial frontal, and precuneus/posterior cingulate regions. The contrast between AO and appetitive control odors (ApCO; chocolate and grape) was similarly larger in the orbital, medial frontal, precuneus, and posterior cingulate/retrosplenial areas, with the most robust finding being a potentiated response in the posterior cingulate/retrosplenial area. The orbital region is similar to an area previously shown to manifest satiety-related decreases in activity induced by food cues.

CONCLUSIONS

The results suggest that priming exposure to alcohol renders a limbic network more responsive to alcohol cues, potentially enhancing desire to drink.

Aripiprazole effects on alcohol consumption and subjective reports in a clinical laboratory paradigm--possible influence of self-control

INTRODUCTION

There has been increasing interest in the use of medications that affect the dopamine receptor in the treatment of alcoholism. Aripiprazole has the unique pharmacology of being a partial dopamine agonist serving to stabilize brain dopamine systems in both frontal cortical and subcortical areas. As such, it might act to dampen alcohol reinforcement and craving and/or alter control over alcohol use. The current clinical laboratory study was conducted to evaluate the safety and efficacy of aripiprazole as a potential agent to alter drinking and objective effects of alcohol.

METHODS

Thirty nontreatment seeking alcoholics were enrolled in a subacute human laboratory study and received double-blind treatment with up to 15 mg of aripiprazole (n = 15) or identical placebo (n = 15) for 8 days. Tolerability and utility of aripiprazole was monitored during natural drinking over the first 6 days of medication treatment and also during a free choice limited access alcohol consumption paradigm following an initial drink of alcohol in a bar-lab setting on Day 8.

RESULTS

Aripiprazole was well tolerated and reduced drinking in nontreatment seeking alcoholics over 6 days of natural drinking--especially in those with lower self control (more impulsive). It also reduced drinks in the bar-lab after a priming drink and broke the link between priming drink induced stimulation and further drinking. During the bar-lab drinking session, there were no differences in subjective high, intoxication, or craving between subjects treated with aripiprazole or placebo.

DISCUSSION

This study joins several others in demonstrating the utility of subacute dosing laboratory paradigms for evaluating medication effects in alcoholics. Aripiprazole was well tolerated and lowered alcohol use, especially in those with lower impulse control. Further study is needed to determine the safety and utility of aripiprazole in the treatment of alcoholism and if subgroups of alcoholics are more likely to respond.

Nucleus accumbens AGS3 expression drives ethanol seeking through G betagamma

Approximately 90% of alcoholics relapse within 4 years, in part because of an enhanced motivation to seek alcohol (EtOH). A novel G protein modulator (Gpsm1/AGS3) was up-regulated in the rat nucleus accumbens core (NAcore) but not in other limbic nuclei during abstinence from operant EtOH self-administration. Furthermore, NAcore AGS3 knockdown reduced EtOH seeking to pre-abstinence levels in a novel rat model of compulsive, human EtOH seeking. AGS3 can both inhibit G protein G i alpha-mediated signaling and stimulate G betagamma-mediated signaling. Accordingly, sequestration of G betagamma, but not G i alpha knockdown, significantly reduced EtOH seeking to pre-abstinence levels. Thus, AGS3 and G betagamma are hypothesized to gate the uncontrolled motivation to seek EtOH during abstinence. AGS3 up-regulation during abstinence may be a key determinant of the transition from social consumption to compulsion-like seeking during relapse.

Quantitative electroencephalographic (qEEG) correlates of craving during virtual reality therapy in alcohol-dependent patients

Virtual reality (VR) is an evolving technology that is being applied to treat a wide range of medical and psychiatric diseases. A virtual reality therapy (VRT) with multisensory stimulation has been applied to patients with alcohol dependence (ADP). We hypothesized that the VRTP for alcohol dependence would reduce the craving for alcohol and increase alpha wave activity in frontal areas of individuals with ADP. Twenty ADP and eighteen ADP were exposed to a series of 10 VRTP sessions (VRTP-ADP) and cognitive behavioral therapy (nVRTP-ADP), respectively. Fifteen healthy controls were exposed to VRTP for comparing the changes of craving and EEG during all three phases of VRTP. The VRTP-ADP exhibited a greater decrease in craving after the 10th VRTP session, when compared to the nVRTP-ADP. Compared to the healthy control subjects, VRTP-ADP group showed higher magnitude of the change in craving throughout VRTP sessions. These results suggest that VRTP may be useful as an adjunct to treating alcohol dependence but may also serve as an evaluation tool to identify high-risk patients.

Naltrexone for the management of alcohol dependence

A 44-year-old businessman with a history of hypertension presents for evaluation with a report of being under stress at work and home, which has led to “unsatisfactory” sleep. Although there is some despondency, screening for depression is negative. His blood pressure is 158/98 mm Hg. Laboratory results include a mean corpuscular volume of 102 fl (normal range, 80 to 100), an alanine aminotransferase level of 60 U per liter (normal range, 7 to 41), an aspartate aminotransferase level of 45 U per liter (normal range, 12 to 38), and a γ-glutamyltransferase level of 110 U per liter (normal range, 9 to 58). His physician asks about alcohol consumption, and the patient admits that perhaps he drinks “more than he should,” since he often wakes up with a hang-over and arrives late to work. After weekend golf outings, he comes home intoxicated, leading to arguments with his wife and embarrassment in front of his children. He has been quietly wondering about the need to cut down or stop drinking and wants some advice. His physician discusses medication or a referral to an alcohol clinic for further evaluation. Naltrexone is proposed as a treatment option.

Separating the effects of alcohol and expectancy on brain activation: an fMRI working memory study

The aim of this study was to use BOLD fMRI to evaluate the effect of alcohol intoxication on neuronal activation, when controlling for expectancy. Behavioural studies have shown that both alcohol intoxication and expectancy affect cognition, mood and behaviour. However, previous neuroimaging studies have not separated the effects of alcohol intoxication from the possible confounding effects of expectancy. Forty-five healthy male participants participated in the study. A balanced placebo design with four groups was used together with a working memory paradigm. Half of the participants consumed a soft-drink before the MR scanning session (half of them were correctly informed about the content of their drink, and half were incorrectly informed that they consumed an alcoholic beverage), and the other half consumed an alcoholic beverage before the MR scanning session (half of them were correctly informed about the content of their drink, and half were incorrectly informed that they consumed a soft-drink). A blood alcohol concentration (BAC) of 0.08% was used as the alcohol intoxication level. The most conspicuous result was that alcohol intoxication decreased neuronal activation especially in the dorsal anterior cingulate cortex (dACC) and in prefrontal areas, while expectancy increased neuronal activation in the same areas. This study shows that alcohol intoxication and expectancy have opposite effects on neuronal activation. The present results could have implications for pharmacological imaging studies.

Striatal sensitivity to reward deliveries and omissions in substance dependent patients

Some motivational theories of substance dependence (SD) posit either pathologically increased or decreased ventral striatum (VS) recruitment by cues for nondrug rewards. The incentive-sensitization hypothesis, alternatively, attributes SD to enhanced incentive salience of drug-predictive cues specifically, with no requirement for altered nondrug incentive processing. We assessed whether individuals undergoing inpatient therapy for SD are characterized by altered recruitment of mesolimbic incentive neurocircuitry by cues and deliveries of nondrug rewards. During functional magnetic resonance imaging, substance-dependent patients (SDP) and controls performed a modified monetary incentive delay task featuring: a) anticipatory cues that signaled opportunities to respond to a target to either win money or avoid losing money, b) notifications of wins and losses, and c) unexpected replacement of reward trial outcomes with a demand to repeat the trial. Both anticipatory reward cues and loss cues elicited similar mood responses and VS activation between SDP and controls. However, in SDP (but not controls), reward notifications also activated VS and mesial frontal cortex, and loss notifications activated anterior insula. Finally, substitution of expected outcomes in reward trials with notifications to repeat the trial deactivated the VS in SDP but not in controls. These data do not suggest that SD is characterized by altered recruitment of VS circuitry by cues for nondrug incentives. Rather, SDP may instead have increased limbic system sensitivity to reward and loss delivery, consistent with the role of impulsivity in SD.

Exposure to the taste of alcohol elicits activation of the mesocorticolimbic neurocircuitry

A growing number of imaging studies suggest that alcohol cues, mainly visual, elicit activation in mesocorticolimbic structures. Such findings are consistent with the growing recognition that these structures play an important role in the attribution of incentive salience and the pathophysiology of addiction. The present study investigated whether the presentation of alcohol taste cues can activate brain regions putatively involved in the acquisition and expression of incentive salience. Using functional magnetic resonance imaging, we recorded BOLD activity while delivering alcoholic tastes to 37 heavy drinking but otherwise healthy volunteers. The results yielded a pattern of BOLD activity in mesocorticolimbic structures (ie prefrontal cortex, striatum, ventral tegmental area/substantia nigra) relative to an appetitive control. Further analyses suggested strong connectivity between these structures during cue-elicited urge and demonstrated significant positive correlations with a measure of alcohol use problems (ie the Alcohol Use Disorders Identification Test). Thus, repeated exposure to the taste alcohol in the scanner elicits activation in mesocorticolimbic structures, and this activation is related to measures of urge and severity of alcohol problems.

Effect of naltrexone and ondansetron on alcohol cue-induced activation of the ventral striatum in alcohol-dependent people

CONTEXT

Medication for the treatment of alcoholism is currently not particularly robust. Neuroimaging techniques might predict which medications could be useful in the treatment of alcohol dependence.

OBJECTIVE

To explore the effect of naltrexone, ondansetron hydrochloride, or the combination of these medications on cue-induced craving and ventral striatum activation.

DESIGN

Functional brain imaging was conducted during alcohol cue presentation.

SETTING

Participants were recruited from the general community following media advertisement. Experimental procedures were performed in the magnetic resonance imaging suite of a major training hospital and medical research institute.

PATIENTS

Ninety non-treatment-seeking alcohol-dependent (by DSM-IV criteria) and 17 social drinking (< 14 drinks per week) paid volunteers recruited through advertisements at an academic center.

INTERVENTIONS

A taste of alcohol and a series of alcohol-related pictures, neutral beverage pictures, and visual control images were provided to volunteers after 7 days of double-blind randomly assigned daily dosing with 50 mg of naltrexone (n = 23), 0.50 mg of ondansetron hydrochloride (n = 23), the combination of the 2 medications (n = 20), or matching placebos (n = 24).

MAIN OUTCOME MEASURES

Difference in brain blood oxygen level-dependent magnetic resonance when viewing alcohol pictures vs neutral beverage pictures with a particular focus on ventral striatum activity comparison across medication groups. Self-ratings of alcohol craving.

RESULTS

The combination treatment decreased craving for alcohol. Naltrexone with (P = .02) or without (P = .049) ondansetron decreased alcohol cue-induced activation of the ventral striatum. Ondansetron by itself was similar to naltrexone and the combination in the overall analysis but intermediate in a region-specific analysis.

CONCLUSIONS

Consistent with animal data that suggest that both naltrexone and ondansetron reduce alcohol-stimulated dopamine output in the ventral striatum, the current study found evidence that these medications, alone or in combination, could decrease alcohol cue-induced activation of the ventral striatum, consistent with their putative treatment efficacy.

Frontal white matter and cingulum diffusion tensor imaging deficits in alcoholism

BACKGROUND

Alcoholism-related deficits in cognition and emotion point toward frontal and limbic dysfunction, particularly in the right hemisphere. Prefrontal and anterior cingulate cortices are involved in cognitive and emotional functions and play critical roles in the oversight of the limbic reward system. In the present study, we examined the integrity of white matter tracts that are critical to frontal and limbic connectivity.

METHODS

Diffusion tensor magnetic resonance imaging (DT-MRI) was used to assess functional anisotropy (FA), a measure of white matter integrity, in 15 abstinent long-term chronic alcoholic and 15 demographically equivalent control men. Voxel-based and region-based analyses of group FA differences were applied to these scans.

RESULTS

Alcoholic subjects had diminished frontal lobe FA in the right superior longitudinal fascicles II and III, orbitofrontal cortex white matter, and cingulum bundle, but not in corresponding left hemisphere regions. These right frontal and cingulum white matter regional FA measures provided 97% correct group discrimination. Working Memory scores positively correlated with superior longitudinal fascicle III FA measures in control subjects only.

CONCLUSIONS

The findings demonstrate white matter microstructure deficits in abstinent alcoholic men in several right hemisphere tracts connecting prefrontal and limbic systems. These white matter deficits may contribute to underlying dysfunction in memory, emotion, and reward response in alcoholism.

fMRI of alcohol craving after individual cues: a follow-up case report

Alcohol addiction is typically associated with intense alcohol craving triggered by internal or environmental cues linked with past alcohol use. We used functional magnetic resonance imaging (fMRI) to record cerebral correlates of craving in an alcoholic patient. Craving was evoked by highly individual cues associated with past alcohol use and was assessed before (T1) and after an 8-month period of psychotherapy (T2). To control for effects of life event memories related to non alcoholic cravings, the patient provided two events from periods of his life when he experienced caffeine craving. We detected activation of the superior temporal lobe during recall of a highly alcohol craving situation (T1 minus T2), whereas we did not observe any activation during coffee craving recall when pre und post activations were compared. These results indicate that the superior temporal lobe may be involved when alcohol craving is initiated by individual verbal cues. Further studies using individual cues are needed to explore the neural correlates of alcohol craving.

Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: a double-blind, sham-controlled study

BACKGROUND

Functional neuroimaging studies have shown that specific brain areas are associated with alcohol craving including the dorsolateral prefrontal cortex (DLPFC). We tested whether modulation of DLPFC using transcranial direct current stimulation (tDCS) could alter alcohol craving in patients with alcohol dependence while being exposed to alcohol cues.

METHODS

We performed a randomized sham-controlled study in which 13 subjects received sham and active bilateral tDCS delivered to DLPFC (anodal left/cathodal right and anodal right/cathodal left). For sham stimulation, the electrodes were placed at the same positions as in active stimulation; however, the stimulator was turned off after 30s of stimulation. Subjects were presented videos depicting alcohol consumption to increase alcohol craving.

RESULTS

Our results showed that both anodal left/cathodal right and anodal right/cathodal left significantly decreased alcohol craving compared to sham stimulation (p<0.0001). In addition, we found that following treatment, craving could not be further increased by alcohol cues.

CONCLUSIONS

Our findings showed that tDCS treatment to DLPFC can reduce alcohol craving. These findings extend the results of previous studies using noninvasive brain stimulation to reduce craving in humans. Given the relatively rapid suppressive effect of tDCS and the highly fluctuating nature of alcohol craving, this technique may prove to be a valuable treatment strategy within the clinical setting.

Inhibitory control and emotional stress regulation: neuroimaging evidence for frontal-limbic dysfunction in psycho-stimulant addiction

This review focuses on neuroimaging studies that examined stress processing and regulation and cognitive inhibitory control in patients with psycho-stimulant addiction. We provide an overview of these studies, summarizing converging evidence and discrepancies as they occur in the literature. We also adopt an analytic perspective and dissect these psychological processes into their sub-components, to identify the neural pathways specific to each component process and those that are more specifically involved in psycho-stimulant addiction. To this aim we refer frequently to studies conducted in healthy individuals. Despite the separate treatment of stress/affect regulation, stress-related craving or compulsive drug seeking, and inhibitory control, neural underpinnings of these processes overlap significantly. In particular, the ventromedial prefrontal regions including the anterior cingulate cortex, amygdala and the striatum are implicated in psychostimulant dependence. Our overarching thesis is that prefrontal activity ensures intact emotional stress regulation and inhibitory control. Altered prefrontal activity along with heightened striatal responses to addicted drug and drug-related salient stimuli perpetuates habitual drug seeking. Further studies that examine the functional relationships of these neural systems will likely provide the key to understanding the mechanisms underlying compulsive drug use behaviors in psycho-stimulant dependence.

Representation of Capsaicin-evoked Urge-to-Cough in the Human Brain Using Functional Magnetic Resonance Imaging

RATIONALE

Coughing in humans is typically preceded by a desire (or urge) to cough. The neural circuitry involved in sensing airway irritation and generating the urge-to-cough in humans is essentially unknown.

OBJECTIVES

The aim of the present study was to use functional brain imaging to describe the supramedullary regions that are activated in humans during capsaicin inhalation.

METHODS

Experiments were performed on 10 healthy subjects (5 males, 5 females). Capsaicin doses were individually tailored to evoke a transient and reversible urge-to-cough. Blood oxygen level-dependent (BOLD) functional magnetic resonance measures were collected during repeated 24-second challenges with capsaicin or saline inhalation and subjects were asked to rate the urge-to-cough intensity of each challenge.

MEASUREMENTS AND MAIN RESULTS

Capsaicin inhalation reliably evoked an urge-to-cough, which was associated with activations in a variety of brain regions, including the insula cortex, anterior midcingulate cortex, primary sensory cortex, orbitofrontal cortex, supplementary motor area, and cerebellum.

CONCLUSIONS

These data provide the first insights into the cortical neuronal network involved in sensing airway irritation and modulating coughing in humans.