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1.
Subst Use Misuse ; 59(8): 1221-1227, 2024.
Article in English | MEDLINE | ID: mdl-38533542

ABSTRACT

Objective: Tobacco use is elevated among individuals with eating disorders (EDs). Yet, further research is needed to understand associations between cigarette and e-cigarette use patterns and ED symptomatology. To gain a more comprehensive understanding of tobacco use and EDs, this study characterized ED symptomatology and tobacco use patterns, including exclusive cigarette use, e-cigarette use, dual use, and nonuse. Method: Young adults aged 18-24 years who self-reported exclusive cigarette, e-cigarette, dual, or nonuse (N = 2500) were recruited via Lucid, an online survey management company. Participants completed questionnaires assessing body dissatisfaction, global ED psychopathology, binge eating and self-induced vomiting frequency, and demographics. ED diagnostic groups included: anorexia nervosa (AN), bulimia spectrum eating disorders (BSED), atypical AN, and night eating syndrome (NES). Results: Multinomial logistic models revealed those with AN were more likely to be dual users, those with atypical AN were more likely to be exclusive e-cigarette users, and participants with a BSED or NES were more likely to be exclusive e-cigarette or dual users, compared to those without an ED. General linear models suggested body dissatisfaction and global ED psychopathology were higher among exclusive e-cigarette and dual users, while binge eating and self-induced vomiting frequencies were greater among all tobacco use groups compared to nonusers. Discussion: Our findings suggest young adults with ED symptomatology were more likely to be users of e-cigarettes exclusively or dual users. It will be necessary to examine how these associations manifest using longitudinal and clinical populations in future research.


Subject(s)
Electronic Nicotine Delivery Systems , Feeding and Eating Disorders , Vaping , Humans , Female , Young Adult , Male , Adolescent , Feeding and Eating Disorders/psychology , Feeding and Eating Disorders/epidemiology , Vaping/psychology , Vaping/epidemiology , Electronic Nicotine Delivery Systems/statistics & numerical data , Cigarette Smoking/epidemiology , Cigarette Smoking/psychology , Body Dissatisfaction/psychology , Night Eating Syndrome/epidemiology , Night Eating Syndrome/psychology , Surveys and Questionnaires
2.
Hum Brain Mapp ; 44(4): 1476-1495, 2023 03.
Article in English | MEDLINE | ID: mdl-36440955

ABSTRACT

One of the core questions in Neuro-economics is to determine where value is represented. To date, most studies have focused on simple options and identified the ventromedial prefrontal cortex (VMPFC) as the common value region. We report the findings of an fMRI study in which we asked participants to make pairwise comparisons involving options of varying complexity: single items (Control condition), bundles made of the same two single items (Scaling condition) and bundles made of two different single items (Bundling condition). We construct a measure of choice consistency to capture how coherent the choices of a participant are with one another. We also record brain activity while participants make these choices. We find that a common core of regions involving the left VMPFC, the left dorsolateral prefrontal cortex (DLPFC), regions associated with complex visual processing and the left cerebellum track value across all conditions. Also, regions in the DLPFC, the ventrolateral prefrontal cortex (VLPFC) and the cerebellum are differentially recruited across conditions. Last, variations in activity in VMPFC and DLPFC value-tracking regions are associated with variations in choice consistency. This suggests that value based decision-making recruits a core set of regions as well as specific regions based on task demands. Further, correlations between consistency and the magnitude of signal change with lateral portions of the PFC suggest the possibility that activity in these regions may play a causal role in decision quality.


Subject(s)
Magnetic Resonance Imaging , Prefrontal Cortex , Humans , Prefrontal Cortex/diagnostic imaging , Dorsolateral Prefrontal Cortex , Choice Behavior
3.
Tob Control ; 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37940405

ABSTRACT

BACKGROUND: This clinical experiment tested the effects of exposure to e-cigarettes with WS-23 or menthol cooling additives on user appeal and sensory attributes, and, secondarily, whether WS-23 effects generalised across base characterising flavour, nicotine concentration, or nicotine/tobacco product use status. METHODS: In this within-participant double-blind experiment, adult tobacco/nicotine users administered standardised puffs of 18 different e-cigarette solutions in randomised sequences using a pod-style device. Each of three base characterising e-cigarette flavour solutions ('bold tobacco', 'mango,' 'wintergreen') in both 2% and 4% concentrations of nicotine benzoate salt were manipulated by adding either: (1) Menthol (0.5%), (2) WS-23 (0.75%) or (3) No cooling agent. After each administration, participants rated 3 appeal and 5 sensory attributes (0-100 scales). RESULTS: Participants (n=84; M(SD)=38.6 (13.6) years old) were either exclusive e-cigarette (25.0%), cigarette (36.9%) or dual (38.1%) users. WS-23 versus no coolant products produced higher liking, willingness to use again, smoothness, and coolness and lower disliking, bitterness, and harshness ratings (|B|difference range: 4.8 to 20.1; ps<0.005). Menthol (vs no coolant) increased willingness to use again and reduced harshness and coolness (ps<0.05). Flavours with WS-23 (vs menthol) were rated as smoother, cooler and less harsh (ps<0.05). Coolant effects did not differ by base flavour, nicotine concentration, or tobacco use status. CONCLUSIONS: Adding synthetic coolant WS-23 to e-cigarettes appears to make the vaping user experience more appealing, regardless of characterising base flavour. Regulatory agencies should be aware that the manufacturing process of adding synthetic coolants may increase the attractiveness of various e-cigarette products.Cite Now.

4.
Arch Phys Med Rehabil ; 104(3): 390-402, 2023 03.
Article in English | MEDLINE | ID: mdl-36167117

ABSTRACT

OBJECTIVE: To determine the momentary effect of social-cognitive factors, in addition to motor capability, on post-stroke paretic arm/hand use in the natural environment. DESIGN: A 5-day observational study in which participants were sent 6 Ecological Momentary Assessment (EMA) prompts/day. SETTING: Participants' daily environment. PARTICIPANTS: Community-dwelling, chronic stroke survivors with right-dominant, mild-moderate upper extremity paresis (N=30). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Time duration of bimanual and unimanual paretic arm/hand use indexed by accelerometry; social-cognitive factors (social context, self-efficacy, mood) captured by EMA; motor capability of the paretic limb measured by Fugl-Meyer Upper Extremity Motor Assessment (FM). RESULTS: After accounting for participants' motor capability, we found that momentary social context (alone or not) and self-efficacy significantly predicted post-stroke paretic arm/hand use behavior in the natural environment. When participants were not alone, paretic arm/hand movement increased both with and without the less-paretic limb (bimanual and unimanual movements, P=.018 and P<.001, respectively). Importantly, participants were more likely to use their paretic arm/hand (unimanually) if they had greater self-efficacy for limb use (P=.042). EMA repeated-measures provide a real-time approach that captures the natural dynamic ebb and flow of social-cognitive factors and their effect on daily arm/hand use. We also observed that people with greater motor impairments (FM<50.6) increase unimanual paretic arm/hand movements when they are not alone, regardless of motor capability. CONCLUSIONS: In addition to motor capability, stroke survivors' momentary social context and self-efficacy play a role in paretic arm/hand use behavior. Our findings suggest the development of personalized rehabilitative interventions which target these factors to promote daily paretic arm/hand use. This study highlights the benefits of EMA to provide real-time information to unravel the complexities of the biopsychosocial (ie, motor capability and social-cognitive factors) interface in post-stroke upper extremity recovery.


Subject(s)
Stroke Rehabilitation , Stroke , Humans , Arm , Self Efficacy , Ecological Momentary Assessment , Upper Extremity , Paresis , Accelerometry , Social Environment
5.
Subst Use Misuse ; 56(7): 997-1004, 2021.
Article in English | MEDLINE | ID: mdl-33784957

ABSTRACT

BACKGROUND AND OBJECTIVES: Social distancing policies have been widely adopted in response to the COVID-19 pandemic. High levels of social connection are positively associated with beneficial health outcomes, while social isolation is associated with poor long-term health outcomes including reduced life expectancy. The present study evaluates the impact of social distancing measures during the early period of COVID-19 on substance use behaviors among those in the United States. Methods: We used an internet-based survey with participants (n = 157; 86 male) reporting a history of problems related to drug use. We relied on ANOVA and logistic regression techniques to assess the associations between social connection and substance use. Results: People with more severe drug use problems reported feeling more socially isolated during social distancing. Those who primarily use alcohol reported higher global feelings of social connection than those who primarily use opioids. During social distancing, participants reported an increase in alcohol and cigarette consumption, and a decrease in cocaine use. Lastly, those who reported using drugs for social reasons were less likely to have decreased substance use during social distancing. Conclusions: The current study provides evidence that social distancing guidelines have impacted both substance use behaviors and feelings of social and physical connection. Further, there are differential impacts based on drug of choice. These results advance delineation of the connection between sociality and drug use.


Subject(s)
COVID-19 , Physical Distancing , Public Policy , Substance-Related Disorders , Adult , Aged , COVID-19/epidemiology , COVID-19/prevention & control , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Substance-Related Disorders/epidemiology , United States/epidemiology , Young Adult
6.
Cogn Behav Ther ; 50(4): 276-294, 2021.
Article in English | MEDLINE | ID: mdl-33706676

ABSTRACT

The COVID-19 pandemic presents unique stressors (e.g. social isolation) that may increase substance use risk among young adults with a history of emotional disturbance. This study examined whether emotional disorder symptoms and transdiagnostic vulnerabilities during adolescence predicted young adult substance use during COVID-19, and whether using substances to cope with the pandemic's social conditions mediated these associations. Adolescents (N = 2,120) completed baseline surveys assessing transdiagnostic emotional vulnerabilities (anhedonia, distress intolerance, anxiety sensitivity, negative urgency) and symptoms (major depression[MD], generalized anxiety[GAD], panic disorder[PD], social phobia[SP], obsessive-compulsive disorder[OCD]) in adolescence (September-December 2016; M[SD] age = 17.45[0.38]). At follow-up (May-August 2020; M[SD] age = 21.16[0.39]), past 30-day substance use and using substances to cope with social isolation during the pandemic were reported. Adjusted models showed that baseline distress intolerance, anxiety sensitivity, negative urgency, and MD symptoms each significantly predicted higher number of past-month single-substance using days and number of substances used at follow-up (ßs = 0.04-0.06). In each case, associations were mediated by tendency to use substances to cope with the pandemic (ßindirect range: 0.028-0.061). To mitigate disproportionate escalation of substance use in young adults with a history of certain types of emotional disturbance, interventions promoting healthy coping strategies to deal with the pandemic's social conditions warrant consideration.


Subject(s)
Adaptation, Psychological , Anxiety Disorders/psychology , COVID-19/psychology , Depressive Disorder/psychology , Recreational Drug Use/psychology , Affective Symptoms/psychology , Anxiety/psychology , Female , Humans , Male , Pandemics , Young Adult
7.
Behav Brain Sci ; 44: e50, 2021 04 26.
Article in English | MEDLINE | ID: mdl-33899717

ABSTRACT

Ainslie's target article provides a map of distinct mechanisms relevant to self-control, potentially providing needed precision to the field. He also breaks new ground in characterizing the symbiotic relationship between suppression and resolve. In this commentary, I argue that one behaviorism-based feature of his framework, present-state independence, is unjustified and unnecessary for the broader claims of the theory.


Subject(s)
Behaviorism , Humans
8.
Eur J Neurosci ; 52(6): 3652-3662, 2020 09.
Article in English | MEDLINE | ID: mdl-32176392

ABSTRACT

Psychological states can influence motor performance and learning. In Parkinson's disease (PD), placebo effects or expectancies for pharmacological treatment benefits are not uncommon, but little is known about whether self-efficacy, beliefs about personal performance capabilities, may play a role in this population. To address this question, we investigated whether experimental manipulations designed to enhance self-efficacy would benefit motor performance and learning in PD. A motor learning paradigm was utilized to determine the short-term (i.e., practice) and longer-term (i.e., retention) impact of self-efficacy enhancement when 44 individuals with PD (Hoehn and Yahr stage I-III) acquired a challenging balance skill. Using stratified randomization by Hoehn and Yahr stage, participants were assigned to a control group or one of two investigational groups: (a) an expectancy-relevant statement that encouraged an incremental mindset in which the balance skill, though initially challenging, was acquirable with practice (incremental theory group, IT), and (b) the expectancy-relevant statement in combination with a criterion for successful performance (incremental theory plus success criteria group, IT + SC). All groups improved their balance performance, but contrary to expectations, investigational groups did not outperform the control group at practice or retention. Unexpectedly, the IT + SC group reported greater nervousness than the control and IT groups, suggesting that the employed success criteria may have induced performance-related anxiety. Regression analyses revealed that self-efficacy increase from initial practice predicted performance at the end of practice and at retention. These findings highlight the potential contribution of psychological factors on motor function and rehabilitation in individuals with PD.


Subject(s)
Parkinson Disease , Humans , Learning , Self Efficacy
9.
Dev Psychopathol ; 32(3): 1045-1058, 2020 08.
Article in English | MEDLINE | ID: mdl-31352914

ABSTRACT

To understand how exposure to victimization during adolescence and the presence of comorbid psychological conditions influence substance use treatment entry and substance use disorder diagnosis from 14 to 25 years old among serious juvenile offenders, this study included 1,354 serious juvenile offenders who were prospectively followed over 7 years. Growth mixture modeling was used to assess profiles of early victimization during adolescence (14-17 years). Discrete time survival mixture analysis was used to assess time to treatment entry and substance use disorder diagnosis. Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) were used as predictors of survival time. Mixture models revealed three profiles of victimization: sustained poly-victimization, moderate/decreasing victimization, and low victimization. Youth in the sustained poly-victimization class were more likely to enter treatment earlier and have a substance use diagnosis earlier than other classes. PTSD was a significant predictor of treatment entry for youth in the sustained poly-victimization class, and MDD was a significant predictor of substance use disorder diagnosis for youth in the moderate/decreasing victimization class. Therefore, substance use prevention programming targeted at youth experiencing poly-victimization in early adolescence-especially those who have PTSD or MDD-is needed.


Subject(s)
Bullying , Crime Victims , Depressive Disorder, Major , Stress Disorders, Post-Traumatic , Substance-Related Disorders , Adolescent , Adult , Depressive Disorder, Major/epidemiology , Humans , Social Justice , Stress Disorders, Post-Traumatic/epidemiology , Substance-Related Disorders/epidemiology , Young Adult
10.
Proc Natl Acad Sci U S A ; 112(20): 6509-14, 2015 May 19.
Article in English | MEDLINE | ID: mdl-25941364

ABSTRACT

Prior studies suggest that fructose compared with glucose may be a weaker suppressor of appetite, and neuroimaging research shows that food cues trigger greater brain reward responses in a fasted relative to a fed state. We sought to determine the effects of ingesting fructose versus glucose on brain, hormone, and appetitive responses to food cues and food-approach behavior. Twenty-four healthy volunteers underwent two functional magnetic resonance imaging (fMRI) sessions with ingestion of either fructose or glucose in a double-blinded, random-order cross-over design. fMRI was performed while participants viewed images of high-calorie foods and nonfood items using a block design. After each block, participants rated hunger and desire for food. Participants also performed a decision task in which they chose between immediate food rewards and delayed monetary bonuses. Hormones were measured at baseline and 30 and 60 min after drink ingestion. Ingestion of fructose relative to glucose resulted in smaller increases in plasma insulin levels and greater brain reactivity to food cues in the visual cortex (in whole-brain analysis) and left orbital frontal cortex (in region-of-interest analysis). Parallel to the neuroimaging findings, fructose versus glucose led to greater hunger and desire for food and a greater willingness to give up long-term monetary rewards to obtain immediate high-calorie foods. These findings suggest that ingestion of fructose relative to glucose results in greater activation of brain regions involved in attention and reward processing and may promote feeding behavior.


Subject(s)
Appetitive Behavior/drug effects , Brain/drug effects , Cues , Feeding Behavior/drug effects , Fructose/pharmacology , Glucose/pharmacology , Adolescent , Blood Glucose/metabolism , Decision Making/drug effects , Female , Food , Fructose/blood , Humans , Insulin/blood , Logistic Models , Magnetic Resonance Imaging , Male , Reward , Young Adult
11.
Appetite ; 116: 464-470, 2017 09 01.
Article in English | MEDLINE | ID: mdl-28551112

ABSTRACT

Feeding behavior is regulated by a complex interaction of central nervous system responses to metabolic signals that reflect nutrient availability and to food cues that trigger appetitive responses. Prior work has shown that the hypothalamus is a key brain area that senses and responds to changes in metabolic signals, and exposure to food cues induces the activation of brain areas involved in reward processing. However, it is not known how the hypothalamic responses to changes in metabolic state are related to reward responses to food cues. This study aimed to understand whether changes in hypothalamic activity in response to glucose-induced metabolic signals are linked to food-cue reactivity within brain areas involved in reward processing. We combined two neuroimaging modalities (Arterial Spin Labeling and Blood Oxygen Level Dependent) to measure glucose-induced changes in hypothalamic cerebral blood flow (CBF) and food-cue task induced changes in brain activity within reward-related regions. Twenty-five participants underwent a MRI session following glucose ingestion and a subset of twenty individuals underwent an additional water session on a separate day as a control condition (drink order randomized). Hunger was assessed before and after drink consumption. We observed that individuals who had a greater reduction in hypothalamic CBF exhibited a greater reduction in left ventral striatum food cue reactivity (Spearman's rho = 0.46, P = 0.048) following glucose vs. water ingestion. These results are the first to use multimodal imaging to demonstrate a link between hypothalamic metabolic signaling and ventral striatal food cue reactivity.


Subject(s)
Cues , Glucose/pharmacology , Hypothalamus/physiology , Adult , Appetite/physiology , Body Mass Index , Diet , Female , Humans , Hunger/physiology , Magnetic Resonance Imaging , Male , Neuroimaging , Photic Stimulation , Reward , Young Adult
12.
Am J Drug Alcohol Abuse ; 43(3): 271-280, 2017 05.
Article in English | MEDLINE | ID: mdl-27439543

ABSTRACT

BACKGROUND: Smokers exhibit an unusually high willingness to forgo a delayed reward of greater magnitude to receive a smaller, more immediate reward. The functional form of such "delay discounting" behavior is central to the discounting-based operationalization of impulsivity, and has implications for theories regarding the basis of steep discounting among smokers and treatment approaches to addiction. OBJECTIVES: We examined the discounting behavior of current smokers, ex-smokers, and never-smokers to determine whether the functional form of discounting differs between these groups. METHODS: Participants completed a 27-item delay discounting questionnaire (25). We used finite mixture modeling in analyzing data as the product of two simultaneous data-generating processes (DGPs), a hyperbolic function and an exponential function, and compared results to a quasi-hyperbolic (QH) approximation, in a relatively large sample (n = 1205). RESULTS: Consistent with prior reports, current smokers exhibited steeper discounting relative to never-smokers across exponential, hyperbolic, and QH models. A mixture model provided significant support for exponential and hyperbolic discounting in the data, and both accounted for roughly 50% of the participants' choices. This mixture model showed a statistically significantly better fit to the data than the exponential, hyperbolic, or QH functions alone. Contrary to the prevailing view, current smokers were not more likely to discount hyperbolically than nonsmokers, and, thus, were not more prone to time-inconsistent discounting. CONCLUSIONS: The results inform the interpretation of steep discounting among smokers and suggest that treatment approaches could be tailored to the type of discounting behavior that smokers exhibit.


Subject(s)
Delay Discounting , Impulsive Behavior , Models, Statistical , Smoking/psychology , Adult , Choice Behavior , Female , Humans , Male , Middle Aged , Reward , Smokers/psychology , Surveys and Questionnaires , Young Adult
13.
Appetite ; 103: 432-440, 2016 08 01.
Article in English | MEDLINE | ID: mdl-26585633

ABSTRACT

Can healthy food-choice habits protect people against temptations of consuming large portion sizes and unhealthy foods? In two studies, we show that the answer is yes, good habits serve this protective role, at least in contexts in which people are not deliberating and thus fall back on habitual responses. In the first study, participants trained with unhealthy habits to approach eating chocolate, but not those trained with healthy habits, succumbed to temptation and ate more chocolates when their self-control resources were depleted. Study 2 extended and clarified these findings by demonstrating the role of environmental cues in eliciting healthy habits when self-control resources are depleted. Participants who had been trained to choose carrots habitually to a pictorial stimulus (i.e., habit cue) subsequently resisted choosing M&Ms as long as the cue was present. This effect of habit cues on healthy food choices suggests the usefulness of manipulating such cues as a means of meeting self-regulatory goals such as portion control.


Subject(s)
Choice Behavior , Craving , Diet, Healthy , Feeding Behavior , Food Preferences/psychology , Portion Size/psychology , Self-Control/psychology , Behavior Control , Chocolate , Cues , Daucus carota , Female , Humans , Male , Motivation , Social Environment , Surveys and Questionnaires
14.
J Neurosci ; 34(22): 7522-30, 2014 May 28.
Article in English | MEDLINE | ID: mdl-24872557

ABSTRACT

The ability to resist current temptations in favor of long-term benefits is a critical human capacity. Despite the extensive studies on the neural mechanisms of intertemporal choices, how the subjective value of immediate and delayed rewards is represented and compared in the brain remains to be elucidated. The present fMRI study addressed this question by simultaneously and independently manipulating the magnitude of immediate and delayed rewards in an intertemporal decision task, combined with univariate analysis and multiple voxel pattern analysis. We found that activities in the posterior portion of the dorsal medial prefrontal cortex (DmPFC) were modulated by the value of immediate options, whereas activities in the adjacent anterior DmPFC were modulated by the subjective value of delayed options. Brain signal change in the ventral mPFC was positively correlated with the "relative value" (the absolute difference of subjective value between two intertemporal alternatives). In contrast, the dorsal anterior cingulate cortex activity was negatively correlated with the relative value. These results suggest that immediate and delayed rewards are separately represented in the dorsal mPFC and compared in the ventral mPFC to guide decisions. The functional dissociation of posterior and anterior DmPFC in representing immediate and delayed reward is consistent with the general structural and functional architecture of the prefrontal cortex and may provide a neural basis for human's unique capacity to delayed gratification.


Subject(s)
Choice Behavior/physiology , Magnetic Resonance Imaging/methods , Prefrontal Cortex/physiology , Reaction Time/physiology , Reward , Female , Humans , Male , Photic Stimulation/methods , Pilot Projects , Young Adult
15.
Int J Neuropsychopharmacol ; 18(7): pyu119, 2015 Jan 20.
Article in English | MEDLINE | ID: mdl-25603861

ABSTRACT

BACKGROUND: Individuals with substance use disorders typically exhibit a predilection toward instant gratification with apparent disregard for the future consequences of their actions. Indirect evidence suggests that low dopamine D2-type receptor availability in the striatum contributes to the propensity of these individuals to sacrifice long-term goals for short-term gain; however, this possibility has not been tested directly. We investigated whether striatal D2/D3 receptor availability is negatively correlated with the preference for smaller, more immediate rewards over larger, delayed alternatives among research participants who met DSM-IV criteria for methamphetamine (MA) dependence. METHODS: Fifty-four adults (n = 27 each: MA-dependent, non-user controls) completed the Kirby Monetary Choice Questionnaire, and underwent positron emission tomography scanning with [(18)F]fallypride. RESULTS: MA users displayed steeper temporal discounting (p = 0.030) and lower striatal D2/D3 receptor availability (p < 0.0005) than controls. Discount rate was negatively correlated with striatal D2/D3 receptor availability, with the relationship reaching statistical significance in the combined sample (r = -0.291, p = 0.016) and among MA users alone (r = -0.342, p = 0.041), but not among controls alone (r = -0.179, p = 0.185); the slopes did not differ significantly between MA users and controls (p = 0.5). CONCLUSIONS: These results provide the first direct evidence of a link between deficient D2/D3 receptor availability and steep temporal discounting. This finding fits with reports that low striatal D2/D3 receptor availability is associated with a higher risk of relapse among stimulant users, and may help to explain why some individuals choose to continue using drugs despite knowledge of their eventual negative consequences. Future research directions and therapeutic implications are discussed.


Subject(s)
Amphetamine-Related Disorders/metabolism , Corpus Striatum/metabolism , Methamphetamine/toxicity , Positron-Emission Tomography , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Reward , Adult , Amphetamine-Related Disorders/diagnostic imaging , Benzamides/administration & dosage , Central Nervous System Stimulants/toxicity , Corpus Striatum/diagnostic imaging , Diagnostic and Statistical Manual of Mental Disorders , Dopamine/metabolism , Female , Fluorine Radioisotopes/administration & dosage , Humans , Male , Middle Aged , Surveys and Questionnaires , Young Adult
16.
Hum Brain Mapp ; 35(8): 3774-87, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24523255

ABSTRACT

In previous work, smokers showed steeper devaluation of delayed rewards than non-smokers. While the neural correlates of this link between nicotine dependence and delay of discounting are not established, altered activity in executive networks may relate to impaired delayed gratification. The goal of this study was to examine neural correlates of discounting and their relation to nicotine dependence. Thirty-nine smokers and 33 non-smokers completed a functional magnetic resonance imaging (fMRI) intertemporal choice task in which they made individualized Hard (similarly valued), easy (dissimilarly valued), and control monetary choices. FMRI data were analyzed using a group independent component analysis and dual regression. Smokers discounted more steeply than non-smokers, although this difference was only significant among severely dependent smokers. Intertemporal choices recruited distinct left- and right-lateralized fronto-parietal networks. A group-by-difficulty interaction indicated that smokers, relative to non-smokers, exhibited less difficulty-sensitivity in the right fronto-parietal network. In contrast, smokers showed greater functional connectivity between the left fronto-parietal network and the left fronto-insular cortex. Moreover, the degree of functional connectivity between the left fronto-parietal network and left fronto-insular cortex was significantly correlated with individual differences in discounting. Thus, greater functional coupling between the anterior insula and left fronto-parietal network is a candidate neural substrate linking smoking and impulsivity. Given the anterior insula's role in interfacing cognitive and interoceptive processing, this altered functional connectivity may relate to an addiction-related bias towards immediate rewards.


Subject(s)
Cerebral Cortex/physiopathology , Delay Discounting/physiology , Smoking/physiopathology , Adult , Brain Mapping , Functional Laterality , Humans , Impulsive Behavior/physiology , Magnetic Resonance Imaging , Male , Neural Pathways/physiopathology , Neuropsychological Tests , Regression Analysis , Severity of Illness Index , Signal Processing, Computer-Assisted
17.
J Neurosci ; 32(21): 7316-24, 2012 May 23.
Article in English | MEDLINE | ID: mdl-22623677

ABSTRACT

Impulsive behavior is thought to reflect a traitlike characteristic that can have broad consequences for an individual's success and well-being, but its neurobiological basis remains elusive. Although striatal dopamine D2-like receptors have been linked with impulsive behavior and behavioral inhibition in rodents, a role for D2-like receptor function in frontostriatal circuits mediating inhibitory control in humans has not been shown. We investigated this role in a study of healthy research participants who underwent positron emission tomography with the D2/D3 dopamine receptor ligand [¹8F]fallypride and BOLD fMRI while they performed the Stop-signal Task, a test of response inhibition. Striatal dopamine D2/D3 receptor availability was negatively correlated with speed of response inhibition (stop-signal reaction time) and positively correlated with inhibition-related fMRI activation in frontostriatal neural circuitry. Correlations involving D2/D3 receptor availability were strongest in the dorsal regions (caudate and putamen) of the striatum, consistent with findings of animal studies relating dopamine receptors and response inhibition. The results suggest that striatal D2-like receptor function in humans plays a major role in the neural circuitry that mediates behavioral control, an ability that is essential for adaptive responding and is compromised in a variety of common neuropsychiatric disorders.


Subject(s)
Benzamides , Corpus Striatum/physiology , Frontal Lobe/physiology , Functional Neuroimaging/psychology , Neural Inhibition/physiology , Receptors, Dopamine D2/physiology , Receptors, Dopamine D3/physiology , Adult , Corpus Striatum/diagnostic imaging , Female , Fluorine Radioisotopes , Frontal Lobe/diagnostic imaging , Functional Neuroimaging/methods , Humans , Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/psychology , Male , Neural Pathways/diagnostic imaging , Neural Pathways/physiology , Positron-Emission Tomography/methods , Positron-Emission Tomography/psychology , Psychomotor Performance/physiology , Pyrrolidines , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism
18.
Neuroimage ; 79: 62-71, 2013 Oct 01.
Article in English | MEDLINE | ID: mdl-23611864

ABSTRACT

Animal studies indicate that different functional networks (FNs), each with a unique timecourse, may overlap at common brain regions. For understanding how different FNs overlap in the human brain and how the timecourses of overlapping FNs are modulated by cognitive tasks, we applied spatial independent component analysis (sICA) to functional magnetic resonance imaging (fMRI) data. These data were acquired from healthy participants while they performed a visual task with parametric loads of attention and working memory. sICA identified a total of 14 FNs, and they showed different extents of overlap at a majority of brain regions exhibiting any functional activity. More FNs overlapped at the higher-order association cortex including the anterior and posterior cingulate, precuneus, insula, and lateral and medial frontoparietal cortices (FPCs) than at the primary sensorimotor cortex. Furthermore, overlapping FNs exhibited concurrent but different task-related modulations of timecourses. FNs showing task-related up- vs. down-modulation of timecourses overlapped at both the lateral and medial FPCs and subcortical structures including the thalamus, striatum, and midbrain ventral tegmental area (VTA). Such task-related, concurrent, but opposite changes in timecourses in the same brain regions may not be detected by current analyses based on General-Linear-Model (GLM). The present findings indicate that multiple cognitive processes may associate with common brain regions and exhibit simultaneous but different modulations in timecourses during cognitive tasks.


Subject(s)
Brain Mapping/methods , Brain/physiology , Cognition/physiology , Nerve Net/physiology , Pattern Recognition, Visual/physiology , Task Performance and Analysis , Adult , Female , Humans , Male , Principal Component Analysis , Young Adult
19.
Behav Brain Sci ; 36(6): 700-1; discussion 707-26, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24304798

ABSTRACT

Kurzban et al. make a convincing case against the idea that willpower is a depleting resource. However, they do not advance a positive account of willpower. Rather than treating "willpower" as a synonym of "executive function," we argue that the term willpower should be designated for mechanisms individuals deploy to reduce dynamic inconsistency in their behavior.


Subject(s)
Mental Fatigue/psychology , Models, Psychological , Humans
20.
Physiol Behav ; 270: 114292, 2023 10 15.
Article in English | MEDLINE | ID: mdl-37442357

ABSTRACT

The hypothalamus has an abundant expression of sweet taste receptors that play a role in glucose sensing and energy homeostasis. Evidence suggests that liking "sweets" can be associated with weight gain, but the relationship between sweet taste preference and hypothalamic regulation of appetite is unknown. This study tested the hypothesis that sweet taste preference is associated with increased hypothalamic activation in response to glucose (a purported neural marker for weight gain risk) and greater longitudinal increases in body mass index (BMI). Fifty-four adults aged 18-35 years with a mean (± SD) BMI of 27.99 ± 5.32 kg/m2 completed the study. Height and weight were measured at baseline and 6-12 months later in a subset of 36 participants. Sweet taste preference was assessed via the Monell 2-series, forced-choice tracking procedure. Arterial spin labeling magnetic resonance imaging was performed before and after oral glucose ingestion to determine hypothalamic blood flow response to glucose. Linear models were used to examine relationships between sweet taste preference and the hypothalamic response to glucose and longitudinal changes in BMI, adjusting for age, sex, and baseline BMI. Sweet taste preference was positively associated with glucose-linked hypothalamic blood flow (beta = 0.017, p = 0.043), adjusted for age, sex and BMI. We also observed a positive association between sweet taste preference and longitudinal change in BMI (beta = 0.088, p = 0.015), adjusted for age, sex and baseline BMI. These findings suggest that heightened sweet taste preference is associated with glucose-linked hypothalamic activation and may be linked to increased susceptibility for weight gain.


Subject(s)
Glucose , Taste , Adult , Humans , Taste/physiology , Food Preferences/physiology , Weight Gain/physiology , Blood Glucose , Hypothalamus/diagnostic imaging
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