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1.  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.
doi:10.1093/alcalc/agq042
PMCID: PMC2930251  PMID: 20729530
2.  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.
doi:10.3109/00952990.2013.875552
PMCID: PMC4542058  PMID: 24588421
3.  Influence of Alcohol Use and Family History of Alcoholism on Neural Response to Alcohol Cues in College Drinkers 
Background
Heavy drinkers show altered functional magnetic resonance imaging (fMRI) response to alcohol cues. Little is known about alcohol cue reactivity among college age drinkers, who show the greatest rates of alcohol use disorders. Family history of alcoholism (FHP) is a risk factor for problematic drinking, but the impact on alcohol cue reactivity is unclear. We investigated the influence of heavy drinking and family history of alcoholism on alcohol cue-related fMRI response among college students.
Method
Participants were 19 family history negative (FHN) light drinkers, 11 FHP light drinkers, 25 FHN heavy drinkers, and 10 FHP heavy drinkers, ages 18–21. During fMRI scanning, participants viewed alcohol images, non-alcohol beverage images, and degraded control images, with each beverage image presented twice. We characterized blood oxygen level-dependent (BOLD) contrast for alcohol vs. non-alcohol images, and examined BOLD response to repeated alcohol images to understand exposure effects.
Results
Heavy drinkers exhibited greater BOLD response than light drinkers in posterior visual association regions, anterior cingulate, medial frontal cortex, hippocampus, amygdala, and dorsal striatum, and hyperactivation to repeated alcohol images in temporo-parietal, frontal, and insular regions (clusters > 8127 μl, p < .05). FHP individuals showed increased activation to repeated alcohol images in temporo-parietal regions, fusiform and hippocampus. There were no interactions between family history and drinking group.
Conclusions
Our results parallel findings of hyperactivation to alcohol cues among heavy drinkers in regions subserving visual attention, memory, motivation, and habit. Heavy drinkers demonstrated heightened activation to repeated alcohol images, which could influence continued drinking. Family history of alcoholism was associated with greater response to repeated alcohol images in regions underlying visual attention, recognition, and encoding, which could suggest aspects of alcohol cue reactivity that are independent of personal drinking. Heavy drinking and family history of alcoholism may have differential impacts on neural circuitry involved in cue reactivity.
doi:10.1111/j.1530-0277.2012.01879.x
PMCID: PMC3548054  PMID: 23078363
fMRI; alcohol; adolescence; cue reactivity; brain
4.  fMRI Response to Alcohol Pictures Predicts Subsequent Transition to Heavy Drinking in College Students 
Addiction (Abingdon, England)  2014;109(4):585-595.
Background and Aims
Young adults show the highest rates of escalating drinking, yet the neural risk mechanisms remain unclear. Heavy drinkers show variant functional magnetic resonance imaging (fMRI) blood oxygen level-dependent (BOLD) response to alcohol cues, which may presage increasing drinking. In this longitudinal study, we ascertained whether BOLD response to alcohol pictures predicted subsequent heavy drinking among college students.
Methods
Participants were forty-three 18- to 21-year-olds in the United States who underwent BOLD scanning and completed monthly substance use surveys over the following year. Participants were categorized according to baseline and follow-up drinking into 13 continuously moderate drinkers, 16 continuously heavy drinkers, and 14 transitioners who drank moderately at baseline but heavily by follow-up. During fMRI scanning at baseline, participants viewed alcohol and matched non-alcohol beverage images.
Results
We observed group differences in alcohol cue-elicited BOLD response in bilateral caudate, orbitofrontal cortex, medial frontal cortex/anterior cingulate and left insula (clusters>2619ml, voxel-wise F(2,40)>3.23, p<.05, whole-brain corrected p<.05), where transitioners hyperactivated compared with moderate and heavy drinkers (all Tukey p<.05). Exploratory factor analysis revealed a single brain network differentiating those who subsequently increased drinking. Exploratory regressions showed that, compared with other risk factors (e.g., alcoholism family history, impulsivity), BOLD response best predicted escalating drinking amount and alcohol-related problems.
Conclusions
Neural response to pictures of alcohol is substantially enhanced among United States college students who subsequently escalate drinking. Greater cue-reactivity is associated with larger increases in drinking and alcohol-related problems, regardless of other baseline factors. Thus, neural cue-reactivity could uniquely facilitate identifying individuals at greatest risk for future problematic drinking.
doi:10.1111/add.12437
PMCID: PMC3951577  PMID: 24304235
alcoholism; imaging; cue reactivity; fMRI; development; adolescence
5.  The Effect Of Alcohol Priming On Neural Markers Of Alcohol Cue-Reactivity 
Background
Priming doses of alcohol are associated with increased desire to drink and disinhibitory effects on subsequent control over drinking. Despite the importance of alcohol priming in the cue-reactivity literature, the effects of priming on brain responses to alcohol cues remains unclear. Further, evidence suggests this relationship may be moderated by OPRM1 genotype.
Methods
Twenty individuals with alcohol dependence (6 females; 90% Caucasian; mean age=29.4) who were prospectively genotyped on the OPRM1 gene underwent two functional magnetic resonance imaging (fMRI) sessions, before and after a priming dose of alcohol, each including a gustatory alcohol cue reactivity paradigm and self-reported craving measures.
Results
Self-reported alcohol craving generally increased and remained higher for alcohol versus water cue presentations across pre- and post-priming scans. Compared to alcohol cues delivered during the post-priming scan, alcohol cues delivered pre-priming were associated with greater activation in regions including the hippocampus, amygdala, inferior frontal gyrus, temporal cortex, and occipital cortex. Controlling for alcoholism severity increased statistical significance of activation in these regions. Follow-up analyses revealed a positive correlation between alcoholism severity and pre- versus post-priming alcohol cue-reactivity primarily in frontal regions. OPRM1 genotype was also found to moderate alcohol cue-reactivity across scans.
Conclusion
This study provides initial evidence of alcohol cue-elicited habituation in fronto-temporal regions, despite continued craving, following a priming dose of alcohol. Further, it provides preliminary evidence for moderating roles of alcoholism severity and OPRM1 genotype on priming-related changes in cue-reactivity, adding to our understanding of the function of alcohol priming in alcohol dependence.
doi:10.3109/00952990.2015.1044608
PMCID: PMC4651007  PMID: 26125586
fMRI; cue-reactivity; priming; alcohol; alcoholism
6.  Action simulation in hallucination-prone adolescents 
Theoretical and empirical accounts suggest that impairments in self-other discrimination processes are likely to promote the expression of hallucinations. Studies using a variety of paradigms involving self-performed actions argue in favor of perspective taking confusion in hallucination-prone subjects. However, our understanding of such processes during adolescence is still at an early stage. The present study thus aims (1) to delineate the neural correlates sustaining mental simulation of actions involving self-performed actions (first-person perspective; 1PP) and other-performed actions (third-person perspective; 3PP) during adolescence (2) to identify atypical activation patterns during 1PP/3PP mental simulation of actions in hallucination-prone adolescents (3) to examine whether differential risk for schizophrenia (clinical vs. genetic) is also associated with differential impairments in the 1PP/3PP mental simulation of actions during adolescence. Twenty-two typically developing controls (Control group; 6 females), 12 hallucination-prone adolescents [auditory hallucination (AH) group; 7 females] and 13 adolescents with 22q11.2 Deletion Syndrome (22q11.2DS group; 4 females) were included in the study. During the fMRI task, subjects were presented with a cue (self-other priming cues) indicating to perform the task using either a first person perspective (“you”-1PP) or a third person perspective (“best friend”-3PP) and then they were asked to mentally simulate actions based on the type of cue. Hallucination-proneness was assessed using a self-report questionnaire [Cardiff Anomalous Perception Scale (CAPS)]. Our results indicated that atypical patterns of cerebral activation, particularly in the key areas of self-other distinction, were found in both groups at risk for auditory hallucinations (AHs and 22q11.2DS). More precisely, adolescents in the AH group presented decreased activations in the right middle occipital gyrus BA19, left cingulate gyrus BA31, and right precuneus BA31 for the 3PP > 1PP contrast. Adolescents in the 22q11.2DS group presented decreased activations in the right superior occipital gyrus BA19, left caudate tail and left precuneus BA7 for the 3PP > 1PP contrast. In comparison to the Control group, only the 22q11.2DS adolescents showed a decreased activation for other-related cues (prime other > prime self contrast) in areas of visual imagery, episodic memory and social cognition. This study characterizes the neural correlates of mental imagery for actions during adolescence, and suggests that a differential risk for hallucination-proneness (clinical vs. genetic) is associated to similar patterns of atypical activations in key areas sustaining self-other discrimination processes. These observations may provide relevant information for future research and prevention strategies with regards to hallucination-proneness during adolescence.
doi:10.3389/fnhum.2013.00329
PMCID: PMC3701149  PMID: 23847502
auditory hallucinations; 22q11.2; action simulation; perspective-taking
7.  Multimodal imaging of repetition priming: Using fMRI, MEG, and intracranial EEG to reveal spatiotemporal profiles of word processing 
NeuroImage  2010;53(2):707-717.
Repetition priming is a core feature of memory processing whose anatomical correlates remain poorly understood. In this study, we use advanced multimodal imaging (functional magnetic resonance imaging (fMRI) and magnetoencephalography; MEG) to investigate the spatiotemporal profile of repetition priming. We use intracranial electroencephalography (iEEG) to validate our fMRI/MEG measurements. Twelve controls completed a semantic judgment task with fMRI and MEG that included words presented once (new, ‘N’) and words that repeated (old, ‘O’). Six patients with epilepsy completed the same task during iEEG recordings. Blood-oxygen level dependent (BOLD) responses for N vs O words were examined across the cortical surface and within regions of interest. MEG waveforms for N vs O words were estimated using a noise-normalized minimum norm solution, and used to interpret the timecourse of fMRI. Spatial concordance was observed between fMRI and MEG repetition effects from 350–450ms within bilateral occipitotemporal and medial temporal, left prefrontal, and left posterior temporal cortex. Additionally, MEG revealed widespread sources within left temporoparietal regions, whereas fMRI revealed bilateral reductions in occipitotemporal and left superior frontal, and increases in inferior parietal, precuneus, and dorsolateral prefrontal activity. BOLD suppression in left posterior temporal, left inferior prefrontal, and right occipitotemporal cortex correlated with MEG repetition-related reductions. IEEG responses from all three regions supported the timecourse of MEG and localization of fMRI. Furthermore, iEEG decreases to repeated words were associated with decreased gamma power in several regions, providing evidence that gamma oscillations are tightly coupled to cognitive phenomena and reflect regional activations seen in the BOLD signal.
doi:10.1016/j.neuroimage.2010.06.069
PMCID: PMC2930128  PMID: 20620212
fMRI; magnetoencepholography; intracranial EEG; memory; language; gamma
8.  Functional MRI of inhibitory processing in abstinent adolescent marijuana users 
Psychopharmacology  2007;194(2):173-183.
Background
Marijuana intoxication appears to impair response inhibition, but it is unclear if impaired inhibition and associated brain abnormalities persist after prolonged abstinence among adolescent users. We hypothesized that brain activation during a go/no-go task would show persistent abnormalities in adolescent marijuana users after 28 days of abstinence.
Methods
Adolescents with (n=16) and without (n=17) histories of marijuana use were compared on blood oxygen level dependent (BOLD) response to a go/no-go task during functional magnetic resonance imaging (fMRI) after 28 days of monitored abstinence. Participants had no neurological problems or Axis I diagnoses other than cannabis abuse/dependence.
Results
Marijuana users did not differ from non-users on task performance but showed more BOLD response than non-users during inhibition trials in right dorsolateral prefrontal, bilateral medial frontal, bilateral inferior and superior parietal lobules, and right occipital gyri, as well as during “go” trials in right prefrontal, insular, and parietal cortices (p<0.05, clusters>943 μl). Differences remained significant even after controlling for lifetime and recent alcohol use.
Conclusions
Adolescent marijuana users relative to non-users showed increased brain processing effort during an inhibition task in the presence of similar task performance, even after 28 days of abstinence. Thus, increased brain processing effort to achieve inhibition may predate the onset of regular use or result from it. Future investigations will need to determine whether increased brain processing effort is associated with risk to use.
doi:10.1007/s00213-007-0823-y
PMCID: PMC2269705  PMID: 17558500
Marijuana; Cannabis; Functional magnetic resonance imaging; Adolescence; Response inhibition; Abstinence
9.  Assessing Cue-Induced Brain Response as a Function of Abstinence Duration in Heroin-Dependent Individuals: An Event-Related fMRI Study 
PLoS ONE  2013;8(5):e62911.
The brain activity induced by heroin-related cues may play a role in the maintenance of heroin dependence. Whether the reinforcement or processing biases construct an everlasting feature of heroin addiction remains to be resolved. We used an event-related fMRI paradigm to measure brain activation in response to heroin cue-related pictures versus neutral pictures as the control condition in heroin-dependent patients undergoing short-term and long-term abstinence. The self-reported craving scores were significantly increased after cue exposure in the short-term abstinent patients (t = 3.000, P = 0.008), but no increase was found in the long-term abstinent patients (t = 1.510, P = 0.149). However, no significant differences in cue-induced craving changes were found between the two groups (t = 1.193, P = 0.850). Comparing between the long-term abstinence and short-term abstinence groups, significant decreases in brain activation were detected in the bilateral anterior cingulated cortex, left medial prefrontal cortex, caudate, middle occipital gyrus, inferior parietal lobule and right precuneus. Among all of the heroin dependent patients, the abstinence duration was negatively correlated with brain activation in the left medial prefrontal cortex and left inferior parietal lobule. These findings suggest that long-term abstinence may be useful for heroin-dependent patients to diminish their saliency value of heroin-related cues and possibly lower the relapse vulnerability to some extent.
doi:10.1371/journal.pone.0062911
PMCID: PMC3646913  PMID: 23667541
10.  Visual Image-Induced Craving for Ethanol (VICE): Development, Validation, and a Pilot fMRI Study 
Background:
Craving induction in a controlled environment is helpful in the research of craving mechanism and its role in development of alcohol dependence (AD). We describe a novel tool Visual Image-induced Craving for Ethanol (VICE) and its effects on brain activation with pilot functional magnetic resonance imaging (fMRI).
Materials and Methods:
Alcohol-related visual cues (ARCs) in 5 scenarios were photographed, which included pictures of bars, alcoholic beverage bottles, pouring of alcohol into glasses, glasses filled with alcohol, and scenes of people sipping alcohol, counterbalanced with neutral pictures (involving water, milk etc.,). Craving scores were obtained from 15 hospitalized patients with AD to validate this tool. In the pilot fMRI (3-Tesla) study, 5 patients were examined using VICE in a symptom provocation model. Group level-fixed effect analysis of brain activation differences was done using SPM8.
Results:
VICE showed a high internal consistency with Cronbach's α coefficient of 0.86, which confirmed its reliability. Concurrent validity of VICE was demonstrated via its convergence with the Penn Alcohol Craving Scale. ARCs had significantly greater mean craving scores than neutral cues in all the 5 scenarios (intentional validity). In the pilot fMRI, patients were found to have greater activation while viewing ARCs compared to the neutral cues in right insular cortex and deficient activation in right orbitofrontal cortex.
Conclusions:
The VICE is a reliable and valid measure of alcohol craving with promising clinical and translational research implications. Preliminary fMRI findings indicate it can be used as a symptom provocation tool for fMRI experiments.
doi:10.4103/0253-7176.130984
PMCID: PMC4031585  PMID: 24860218
Alcohol; craving; imaging; neurobiology; symptom provocation
11.  Neural Correlates of Verbal Learning in Adolescent Alcohol and Marijuana Users 
Addiction (Abingdon, England)  2010;106(3):564-573.
Aims
Alcohol and marijuana are the most widely used intoxicants among adolescents, yet their potential unique and interactive influences on the developing brain are not well established. Brain regions subserving learning and memory undergo continued maturation during adolescence, and may be particularly susceptible to substance-related neurotoxic damage. Here, we characterize brain response during verbal learning among adolescent users of alcohol and marijuana.
Design
Participants performed a verbal paired associates encoding task during fMRI scanning.
Setting
Adolescent subjects were recruited from local public schools and imaged at a University-based fMRI Center.
Participants
Participants were 74 16- to 18-year-olds, divided into four groups: (1) 22 controls with limited alcohol and marijuana experience, (2) 16 binge drinkers, (3) 8 marijuana users, and (4) 28 binge drinking marijuana users.
Measurements
Diagnostic interview assured that all teens were free from neurologic or psychiatric disorders; urine toxicology and breathalyzer verified abstinence for 22–28 days before scanning; a verbal paired associates task was administered during fMRI.
Findings
Groups demonstrated no differences in performance on the verbal encoding task, yet exhibited different brain response patterns. A main effect of drinking pointed to decreased inferior frontal but increased dorsal frontal and parietal fMRI response among binge drinkers (corrected p < .05). There was no main effect of marijuana use. Binge drinking × marijuana interactions were found in bilateral frontal regions (corrected p < .05), where users of either alcohol or marijuana showed greater response than non-users, but users of both substances resembled non-users.
Conclusions
Adolescent substance users demonstrated altered fMRI response relative to nonusing controls, yet binge drinking appeared associated with more differences in activation than marijuana use. Alcohol and marijuana may have interactive effects that alter these differences, particularly in prefrontal brain regions.
doi:10.1111/j.1360-0443.2010.03197.x
PMCID: PMC3423457  PMID: 21134014
adolescence; functional magnetic resonance imaging; verbal learning; cannabis; alcohol; binge drinking
12.  The Impact of Accelerated Right Prefrontal High-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Cue-Reactivity: An fMRI Study on Craving in Recently Detoxified Alcohol-Dependent Patients 
PLoS ONE  2015;10(8):e0136182.
In alcohol-dependent patients craving is a difficult-to-treat phenomenon. It has been suggested that high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) may have beneficial effects. However, exactly how this application exerts its effect on the underlying craving neurocircuit is currently unclear. In an effort to induce alcohol craving and to maximize detection of HF-rTMS effects to cue-induced alcohol craving, patients were exposed to a block and event-related alcohol cue-reactivity paradigm while being scanned with fMRI. Hence, we assessed the effect of right dorsolateral prefrontal cortex (DLPFC) stimulation on cue-induced and general alcohol craving, and the related craving neurocircuit. Twenty-six recently detoxified alcohol-dependent patients were included. First, we evaluated the impact of one sham-controlled stimulation session. Second, we examined the effect of accelerated right DLPFC HF-rTMS treatment: here patients received 15 sessions in an open label accelerated design, spread over 4 consecutive days. General craving significantly decreased after 15 active HF-rTMS sessions. However, cue-induced alcohol craving was not altered. Our brain imaging results did not show that the cue-exposure affected the underlying craving neurocircuit after both one and fifteen active HF-rTMS sessions. Yet, brain activation changes after one and 15 HF-rTMS sessions, respectively, were observed in regions associated with the extended reward system and the default mode network, but only during the presentation of the event-related paradigm. Our findings indicate that accelerated HF-rTMS applied to the right DLPFC does not manifestly affect the craving neurocircuit during an alcohol-related cue-exposure, but instead it may influence the attentional network.
doi:10.1371/journal.pone.0136182
PMCID: PMC4546410  PMID: 26295336
13.  Activation in brain energy regulation and reward centers by food cues varies with choice of visual stimulus 
Objective
To develop a noninvasive method of studying brain mechanisms involved in energy homeostasis and appetite regulation in humans by using visual food cues that are relevant to individuals attempting weight loss.
Design
Functional magnetic resonance imaging (fMRI) was used to compare brain activation in regions of interest between groups of food photographs.
Participants
10 healthy, nonobese women who were not dieting for weight loss.
Measurements
Independent raters viewed food photographs and evaluated whether the foods depicted should be eaten by individuals attempting a calorically-restricted diet. Based on their responses, we categorized photographs into “non-fattening” and “fattening” food groups, the latter characterized by obviously high caloric content and usually also high fat or high sugar content. Blood oxygen level-dependent (BOLD) response was measured by fMRI while participants viewed photographs of “fattening” foods, “non-fattening” foods, and non-food objects.
Results
Viewing photographs of fattening food compared to non-food objects resulted in significantly greater activation in the brainstem; hypothalamus; left amygdala; left dorsolateral prefrontal cortex; left orbitofrontal cortex; right insular cortex; bilateral striatum, including the nucleus accumbens, caudate nucleus, and putamen; bilateral thalamus; and occipital lobe. By comparison, only the occipital region had greater activation by non-fattening food than by object photographs. Combining responses to all food types resulted in attenuation of activation in the brainstem, hypothalamus, and striatum.
Conclusion
These findings suggest that, in nonobese women, neural circuits engaged in energy homeostasis and reward processing are selectively attuned to representations of high-calorie foods that are perceived as fattening. Studies to investigate hormonal action or manipulation of energy balance may benefit from fMRI protocols that contrast energy-rich food stimuli with non-food or low-calorie food stimuli.
doi:10.1038/ijo.2009.56
PMCID: PMC2697279  PMID: 19365394
14.  Inhibition-Induced Forgetting Results from Resource Competition between Response Inhibition and Memory Encoding Processes 
The Journal of Neuroscience  2015;35(34):11936-11945.
Response inhibition is a key component of executive control, but its relation to other cognitive processes is not well understood. We recently documented the “inhibition-induced forgetting effect”: no-go cues are remembered more poorly than go cues. We attributed this effect to central-resource competition, whereby response inhibition saps attention away from memory encoding. However, this proposal is difficult to test with behavioral means alone. We therefore used fMRI in humans to test two neural predictions of the “common resource hypothesis”: (1) brain regions associated with response inhibition should exhibit greater resource demands during encoding of subsequently forgotten than remembered no-go cues; and (2) this higher inhibitory resource demand should lead to memory encoding regions having less resources available during encoding of subsequently forgotten no-go cues. Participants categorized face stimuli by gender in a go/no-go task and, following a delay, performed a surprise recognition memory test for those faces. Replicating previous findings, memory was worse for no-go than for go stimuli. Crucially, forgetting of no-go cues was predicted by high inhibitory resource demand, as quantified by the trial-by-trial ratio of activity in neural “no-go” versus “go” networks. Moreover, this index of inhibitory demand exhibited an inverse trial-by-trial relationship with activity in brain regions responsible for the encoding of no-go cues into memory, notably the ventrolateral prefrontal cortex. This seesaw pattern between the neural resource demand of response inhibition and activity related to memory encoding directly supports the hypothesis that response inhibition temporarily saps attentional resources away from stimulus processing.
SIGNIFICANCE STATEMENT Recent behavioral experiments showed that inhibiting a motor response to a stimulus (a “no-go cue”) impairs subsequent memory for that cue. Here, we used fMRI to test whether this “inhibition-induced forgetting effect” is caused by competition for neural resources between the processes of response inhibition and memory encoding. We found that trial-by-trial variations in neural inhibitory resource demand predicted subsequent forgetting of no-go cues and that higher inhibitory demand was furthermore associated with lower concurrent activation in brain regions responsible for successful memory encoding of no-go cues. Thus, motor inhibition and stimulus encoding appear to compete with each other: when more resources have to be devoted to inhibiting action, less are available for encoding sensory stimuli.
doi:10.1523/JNEUROSCI.0519-15.2015
PMCID: PMC4549404  PMID: 26311775
attention; cognitive control; memory; response inhibition
15.  STABILITY OF FMRI STRIATAL RESPONSE TO ALCOHOL CUES: A HIERARCHICAL LINEAR MODELING APPROACH 
NeuroImage  2011;56(1):61-68.
In functional magnetic resonance imaging (fMRI) studies of alcohol-dependent individuals, alcohol cues elicit activation of the ventral and dorsal aspects of the striatum (VS and DS), which are believed to underlie aspects of reward learning critical to the initiation and maintenance of alcohol dependence. Cue-elicited striatal activation may represent a biological substrate through which treatment efficacy may be measured. However, to be useful for this purpose, VS or DS activation must first demonstrate stability across time. Using hierarchical linear modeling (HLM), this study tested the stability of cue-elicited activation in anatomically and functionally defined regions of interest in bilateral VS and DS. Nine non-treatment-seeking alcohol-dependent participants twice completed an alcohol cue reactivity task during two fMRI scans separated by 14 days. HLM analyses demonstrated that, across all participants, alcohol cues elicited significant activation in each of the regions of interest. At the group level, these activations attenuated slightly between scans, but session-wise differences were not significant. Within-participants stability was best in the anatomically defined right VS and DS and in a functionally defined region that encompassed right caudate and putamen (intraclass correlation coefficients of .75, .81, and .76, respectively). Thus, within this small sample, alcohol cue-elicited fMRI activation had good reliability in the right striatum, though a larger sample is necessary to ensure generalizability and further evaluate stability. This study also demonstrates the utility of HLM analytic techniques for serial fMRI studies, in which separating within-participants variance (individual changes in activation) from between-participants factors (time or treatment) is critical.
doi:10.1016/j.neuroimage.2011.02.004
PMCID: PMC3066261  PMID: 21316465
alcohol; fMRI; cue reactivity; ventral striatum; dorsal striatum; HLM
16.  Prospective associations between brain activation to cocaine and no-go cues and cocaine relapse* 
Drug and alcohol dependence  2013;131(0):44-49.
Background
The ability to predict potential for relapse to substance use following treatment could be very useful in targeting aftercare strategies. Recently, a number of investigators have focused on using neural activity measured by fMRI to predict relapse propensity. The purpose of the present study was to use fMRI to investigate prospective associations between brain reactivity to cocaine and response inhibition cues and relapse to cocaine use.
Methods
Thirty cocaine-dependent participants with clean cocaine urine drug screens (UDS) completed a baseline fMRI scan, including a cocaine-cue reactivity task and a go/no-go response inhibition task. After participating in a brief clinical trial of D-cycloserine for the facilitation of cocaine cue extinction, they returned for a one-week follow-up UDS. Associations between baseline activation to cocaine and inhibition cues and relapse to cocaine use were explored.
Results
Positive cocaine UDS was significantly associated with cocaine cue activation in the right putamen and insula, as well as bilateral occipital regions. Associations between positive cocaine UDS and activation to no-go cues were concentrated in the postcentral gyri, a region involved in response execution.
Conclusions
Although preliminary, these results suggest that brain imaging may be a useful tool for predicting risk for relapse in cocaine-dependent individuals. Further, larger-scale naturalistic studies are needed to corroborate and extend these findings.
doi:10.1016/j.drugalcdep.2013.04.008
PMCID: PMC3703628  PMID: 23683790
fMRI; cue; go no-go; urine drug screen; cocaine; relapse
17.  fMRI Response During Figural Memory Task Performance in College Drinkers 
Psychopharmacology  2013;231(1):10.1007/s00213-013-3219-1.
Rationale
18-25-year-olds show the highest rates of alcohol use disorders (AUD) and heavy drinking, which may have critical neurocognitive implications. Regions subserving memory may be particularly susceptible to alcohol-related impairments.
Objective
We used blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine the neural correlates of visual encoding and recognition among heavy drinking college students. We predicted that heavy drinkers would show worse memory performance and increased frontal/parietal activation and decreased hippocampal response during encoding.
Methods
Participants were 23 heavy drinkers and 33 demographically matched light drinkers, ages 18-20, characterized using quantity/frequency of drinking and AUD diagnosis. Participants performed a figural encoding and recognition task during fMRI. BOLD response during encoding was modeled based on whether each stimulus was subsequently recognized or forgotten (i.e., correct vs. incorrect encoding).
Results
There were no group differences in behavioral performance. Compared to light drinkers, heavy drinkers showed: 1) greater BOLD response during correct encoding in right hippocampus/medial temporal, right dorsolateral prefrontal, left inferior frontal, and bilateral posterior parietal cortices; 2) less left inferior frontal activation and greater bilateral precuneus deactivation during incorrect encoding; and 3) less bilateral insula response during correct recognition (clusters >10,233ul, p<.05 whole-brain).
Conclusions
This is the first investigation of the neural substrates of figural memory among heavy drinking older adolescents. Heavy drinkers demonstrated compensatory hyperactivation of memory-related areas during correct encoding, greater deactivation of default mode regions during incorrect encoding, and reduced recognition-related response. Results could suggest use of different encoding and recognition strategies among heavy drinkers.
doi:10.1007/s00213-013-3219-1
PMCID: PMC3877735  PMID: 23949205
Alcohol; Adolescent; Young Adult; fMRI; Learning; Memory; Cognition
18.  Cue-Elicited Craving in Heroin Addicts at Different Abstinent Time: An fMRI Pilot Study 
Substance Use & Misuse  2012;47(6):631-639.
Objective: We evaluated the effect of short-term and long-term heroin abstinence on brain responses to heroin-related cues using functional magnetic resonance imaging (fMRI). Methods: Eighteen male heroin addicts following short-term abstinence and 19 male heroin addicts following long-term abstinence underwent fMRI scanning while viewing heroin-related and neutral images. Cue-elicited craving and withdrawal symptoms in the subjects were measured. Results: Following short-term abstinence, greater activation was found in response to heroin cues compared to neutral cues in bilateral temporal, occipital, posterior cingulate, anterior cingulate, thalamus, cerebellum, and left hippocampus. In contrast, activations in bilateral temporal and occipital and deactivations in bilateral frontal, bilateral parietal, left posterior cingulate, insula, thalamus, dorsal striatum, and bilateral cerebellum were observed following long-term abstinence. Direct comparisons between conditions showed greater brain reactivity in response to smoking cues following short-term abstinence. In addition, short-term abstinence had more serious withdrawal symptoms than the long-term. Conclusion: The present findings indicate that compared to short-term, long-term abstinence manifests less serious withdrawal symptoms and significantly decreases neural responses to heroin-related cues in brain regions subserving visual sensory processing, attention, memory, and action planning. These findings suggest that long-term abstinence can decrease the salience of conditioned cues, thereby reducing the risk of relapses. The study's limitations are noted.
doi:10.3109/10826084.2011.646381
PMCID: PMC3359800  PMID: 22329835
abstinence; cue-reactivity; craving; heroin dependence; fMRI
19.  Varenicline effects on drinking, craving and neural reward processing among non-treatment-seeking alcohol-dependent individuals 
Psychopharmacology  2014;231(18):3799-3807.
Rationale
The α4β2 nicotinic acetylcholine receptor partial agonist varenicline has been reported to reduce drinking among both heavy-drinking smokers and primary alcoholics, and this effect may be related to varenicline-mediated reduction of alcohol craving. Among smokers, varenicline has been reported to modulate cigarette cue-elicited brain activation in several reward-related areas.
Objectives
This pilot study tested varenicline’s effects on drinking, alcohol craving, and alcohol cue-elicited activation of reward-related brain areas among non-treatment-seeking alcohol-dependent individuals.
Methods
Thirty-five such individuals (mean age = 30, 57% male, 76% heavy drinking days in the past month, 15 smokers) were randomized to either varenicline (titrated to 2 mg) or placebo for 14 days, and were administered an alcohol cue reactivity fMRI task on day 14. A priori regions of interest (ROIs) were bilateral and medial orbitofrontal cortex (OFC), right ventral striatum (VS), and medial prefrontal cortex (mPFC).
Results
Despite good medication adherence, varenicline did not reduce heavy drinking days or other drinking parameters. It did, however, increase self-reported control over alcohol-related thoughts and reduced cue-elicited activation bilaterally in the OFC, but not in other brain areas.
Conclusions
These data indicate that varenicline reduces alcohol craving and some of the neural substrates of alcohol cue reactivity. However, varenicline effects on drinking mediated by cue-elicited brain activation and craving might be best observed among treatment-seekers motivated to reduce their alcohol consumption.
doi:10.1007/s00213-014-3518-1
PMCID: PMC4146648  PMID: 24647921
Varenicline; alcohol; fMRI; neuroimaging; craving
20.  Alcohol Affects Neuronal Substrates of Response Inhibition but Not of Perceptual Processing of Stimuli Signalling a Stop Response 
PLoS ONE  2013;8(9):e76649.
Alcohol impairs inhibitory control, including the ability to terminate an initiated action. While there is increasing knowledge about neural mechanisms involved in response inhibition, the level at which alcohol impairs such mechanisms remains poorly understood. Thirty-nine healthy social drinkers received either 0.4g/kg or 0.8g/kg of alcohol, or placebo, and performed two variants of a Visual Stop-signal task during acquisition of functional magnetic resonance imaging (fMRI) data. The two task variants differed only in their instructions: in the classic variant (VSST), participants inhibited their response to a “Go-stimulus” when it was followed by a “Stop-stimulus”. In the control variant (VSST_C), participants responded to the “Go-stimulus” even if it was followed by a “Stop-stimulus”. Comparison of successful Stop-trials (Sstop)>Go, and unsuccessful Stop-trials (Ustop)>Sstop between the three beverage groups enabled the identification of alcohol effects on functional neural circuits supporting inhibitory behaviour and error processing. Alcohol impaired inhibitory control as measured by the Stop-signal reaction time, but did not affect other aspects of VSST performance, nor performance on the VSST_C. The low alcohol dose evoked changes in neural activity within prefrontal, temporal, occipital and motor cortices. The high alcohol dose evoked changes in activity in areas affected by the low dose but importantly induced changes in activity within subcortical centres including the globus pallidus and thalamus. Alcohol did not affect neural correlates of perceptual processing of infrequent cues, as revealed by conjunction analyses of VSST and VSST_C tasks. Alcohol ingestion compromises the inhibitory control of action by modulating cortical regions supporting attentional, sensorimotor and action-planning processes. At higher doses the impact of alcohol also extends to affect subcortical nodes of fronto-basal ganglia- thalamo-cortical motor circuits. In contrast, alcohol appears to have little impact on the early visual processing of infrequent perceptual cues. These observations clarify clinically-important effects of alcohol on behaviour.
doi:10.1371/journal.pone.0076649
PMCID: PMC3783488  PMID: 24086758
21.  The Association between Cue-Reactivity in the Precuneus and Level of Dependence on Nicotine and Alcohol* 
Drug and alcohol dependence  2014;141:21-26.
Background
Given numerous reports implicating involvement of the precuneus in cue-reactivity paradigms, the goal of this investigation was to examine the relationship between activation of the precuneus in response to drug cues and measures of subjective craving and severity of dependence in volunteers who were comorbid for alcohol and nicotine abuse.
Methods
Forty research participants, who all reported heavy drinking and daily smoking, were recruited (15 women; 70% Caucasian; mean age = 31.2 years) for a functional magnetic resonance imaging (fMRI) session involving a cigarette video-cues task and an alcohol taste-cues task. Mean precuneus activation from both tasks during cue presentation was subjected to bivariate correlation analyses with indices of dependence severity and subjective craving.
Results
Precuneus activation in the contrast of Cigarette Cues vs. Control Cues was positively correlated with scores on the Fagerström Test of Nicotine Dependence (r=0.389, p=0.016), and activation in the Alcohol Cues vs. Control Cues contrast was positively correlated with Alcohol Dependence Scale scores (r=0.338, p=0.038). No correlations with subjective craving were observed (ps>0.05).
Conclusions
These findings indicate that the precuneus is involved in cue reactivity for both cigarettes and alcohol, and that this involvement is moderated by severity of drug dependence. The precuneus may be a cortical locus for neuroplastic changes related to drug dependence.
doi:10.1016/j.drugalcdep.2014.04.026
PMCID: PMC4166553  PMID: 24880692
precuneus; cigarettes; alcohol use disorder; fMRI; cue-reactivity; craving
22.  Distinct and convergent visual processing of high and low spatial-frequency information in faces 
We tested for differential brain response to distinct spatial-frequency (SF) components in faces. During an fMRI experiment, participants were presented with ‘hybrid’ faces containing superimposed low and high SF information from different identities. We used a repetition paradigm where faces at either SF range were independently repeated or changed across consecutive trials. In addition, we manipulated which SF band was attended. Our results suggest that repetition and attention affected partly overlapping occipito-temporal regions but did not interact. Changes of high SF faces increased responses of the right inferior occipital gyrus (IOG) and left inferior temporal gyrus (ITG), with the latter response being also modulated additively by attention. In contrast, the bilateral middle occipital gyrus (MOG) responded to repetition and attention manipulations of low SF. A common effect of high and low SF repetition was observed in the right fusiform gyrus (FFG). Follow-up connectivity analyses suggested direct influence of the MOG (low SF), IOG and ITG (high SF) on the FFG responses. Our results reveal that different regions within occipito-temporal cortex extract distinct visual cues at different SF ranges in faces, and that the outputs from these separate processes project forward to the right FFG, where the different visual cues may converge.
doi:10.1093/cercor/bhl180
PMCID: PMC2600423  PMID: 17283203
attention; DCM; fMRI; human; occipito-temporal cortex; repetition
23.  Simultaneous and Concurrent Polydrug Use of Alcohol and Prescription Drugs: Prevalence, Correlates, and Consequences* 
Journal of studies on alcohol  2006;67(4):529-537.
Objective
In this study, we sought to examine the prevalence, correlates, and consequences associated with simultaneous polydrug use and concurrent polydrug use of alcohol and prescription drugs. For purposes of this investigation, simultaneous polydrug use referred to the co-ingestion of different drugs at the same time, and concurrent polydrug use referred to the use of different drugs on separate occasions within the past 12 months.
Method
Undergraduate students attending a large public midwestern university in the United Sates were randomly selected to self-administer a Web survey. The sample consisted of 4,580 undergraduate students, with a mean (SD) age of 19.9 (2.0) years; the sample consisted of 50% women, and the racial breakdown was 65% while, 13% Asian, 7% black, 5% Hispanic, and 10% other race/ethnicity. The survey assessed simultaneous polydrug use and concurrent polydrug use of alcohol and four classes of prescription drugs: (1) pain medication, (2) stimulant medication, (3) sedative medication, and (4) sleeping medication.
Results
The 12 month prevalence for polydrug use involving alcohol and abusable prescription drugs was 12.1% (including 6.9% simultaneous polydrug use). The majority of polydrug use involving alcohol and each class of prescription drugs was simultaneous polydrug use, with the exception of sleeping medication. Simultaneous polydrug use was more prevalent among undergraduate students who were male, were white, and reported early initiation of alcohol use. Simultaneous polydrug was associated with more alcohol-related and other drug use-related problems than concurrent polydrug use.
Conclusions
Based on the high prevalence and increased risk for consequences associated with simultaneous polydrug use of alcohol and prescription drugs, collegiate prevention efforts aimed at reducing substance abuse should clearly focus on co-ingestion of alcohol and prescription drugs.
PMCID: PMC1761923  PMID: 16736072
24.  Neural Substrates of Resisting Craving during Cigarette Cue Exposure 
Biological psychiatry  2007;62(6):642-651.
Background
In cigarette smokers, the most commonly-reported areas of brain activation during visual cigarette cue exposure are: the prefrontal, anterior cingulate, and visual cortices. We sought to determine changes in brain activity in response to cigarette cues when smokers actively resist craving.
Methods
Forty-two tobacco dependent smokers underwent functional magnetic resonance imaging, during which they were presented with videotaped cues. Three cue presentation conditions were tested: cigarette cues with subjects allowing themselves to crave (cigarette cue crave), cigarette cues with the instruction to resist craving (cigarette cue resist), and matched neutral cues.
Results
Activation was found in the cigarette cue resist (compared to the cigarette cue crave) condition in the left dorsal anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and precuneus. Lower MR signal for the cigarette cue resist condition was found in the cuneus bilaterally, left lateral occipital gyrus, and right post-central gyrus. These relative activations and deactivations were more robust when the cigarette cue resist condition was compared to the neutral cue condition.
Conclusions
Suppressing craving during cigarette cue exposure involves activation of limbic (and related) brain regions and deactivation of primary sensory and motor cortices.
doi:10.1016/j.biopsych.2006.10.026
PMCID: PMC1992815  PMID: 17217932
Nicotine Dependence; functional magnetic resonance imaging; cue-induced cigarette craving; cingulate cortex; visual cortex
25.  fMRI Reactivity to High-Calorie Food Pictures Predicts Short- and Long-Term Outcome in a Weight-Loss Program 
Neuroimage  2012;59(3):2709-2721.
Behavioral studies have suggested that food cues have stronger motivating effects in obese than in normal-weight individuals, which may be a risk factor underlying obesity. Previous cross-sectional neuroimaging studies have suggested that this difference is mediated by increased reactivity to food cues in parts of the reward system in obese individuals. To date, however, only a few prospective neuroimaging studies have been conducted to examine whether individual differences in brain activation elicited by food cues can predict differences in weight change. We used functional magnetic resonance imaging (fMRI) to investigate activation in reward-system as well as other brain regions in response to viewing high-calorie food vs. control pictures in 25 obese individuals before and after a 12-week psychosocial weight-loss treatment and at 9-mo follow-up. In those obese individuals who were least successful in losing weight during the treatment, we found greater pre-treatment activation to high-calorie food vs. control pictures in brain regions implicated in reward-system processes, such as the nucleus accumbens, anterior cingulate, and insula. We found similar correlations with weight loss in brain regions implicated by other studies in vision and attention, such as superior occipital cortex, inferior and superior parietal lobule, and prefrontal cortex. Furthermore, less successful weight maintenance at 9-mo follow-up was predicted by greater post-treatment activation in such brain regions as insula, ventral tegmental area, putamen, and fusiform gyrus. In summary, we found that greater activation in brain regions mediating motivational and attentional salience of food cues in obese individuals at the start of a weight-loss program was predictive of less success in the program and that such activation following the program predicted poorer weight control over a 9-mo follow-up period.
PMCID: PMC3287079  PMID: 22332246
obesity; fMRI; food cues; weight loss; weight maintenance; reward system

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