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1.
Mol Psychiatry ; 28(7): 3055-3062, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37106117

RESUMO

The neurocomputational processes underlying bulimia nervosa and its primary symptoms, out-of-control overeating and purging, are poorly understood. Research suggests that the brains of healthy individuals form a dynamic internal model to predict whether control is needed in each moment. This study tested the hypothesis that this computational process of inhibitory control is abnormally affected by metabolic state (being fasted or fed) in bulimia nervosa. A Bayesian ideal observer model was fit to behavioral data acquired from 22 women remitted from bulimia nervosa and 20 group-matched controls who completed a stop-signal task during two counterbalanced functional MRI sessions, one after a 16 h fast and one after a meal. This model estimates participants' trial-by-trial updating of the probability of a stop signal based on their experienced trial history. Neural analyses focused on control-related Bayesian prediction errors, which quantify the direction and degree of "surprise" an individual experiences on any given trial. Regardless of group, metabolic state did not affect behavioral performance on the task. However, metabolic state modulated group differences in neural activation. In the fed state, women remitted from bulimia nervosa had attenuated prediction-error-dependent activation in the left dorsal caudate. This fed-state activation was lower among women with more frequent past binge eating and self-induced vomiting. When they are in a fed state, individuals with bulimia nervosa may not effectively process unexpected information needed to engage inhibitory control. This may explain the difficulties these individuals have stopping eating after it begins.


Assuntos
Bulimia Nervosa , Bulimia , Transtornos da Alimentação e da Ingestão de Alimentos , Humanos , Feminino , Teorema de Bayes , Encéfalo
2.
J Abnorm Psychol ; 130(8): 862-874, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34843290

RESUMO

Individuals with bulimia nervosa (BN) cycle between periods of binge-eating and compensatory behavior and periods of dietary restraint, suggesting extremes of under and overcontrol that may be metabolic-state related. This study examined the influence of hunger and satiety on impulsivity and neural responding during decision-making. Twenty-three women remitted from BN (RBN) and 20 healthy comparison women (CW) performed a delay discounting task after a 16-hr fast and following a standardized meal during functional neuroimaging. A dual-systems approach examined reward valuation (decision trials where the early reward option was available immediately) and cognitive control (all decision trials). Interactions of Group × Visit (Hungry, Fed) for immediate reward revealed that CW had greater activation when hungry versus fed in the ventral striatum and dorsal caudate, whereas RBN had greater response when fed versus hungry in the dorsal caudate. Compared to CW, RBN showed decreased response when hungry within the left dorsal caudate and ventral striatum and increased response when fed in bilateral dorsal caudate. No differences were found within cognitive control regions or with choice behavior. Reward sensitivity is normally increased when hungry and decreased when fed; our findings in CW provide further support of hunger-based reward sensitivity within the striatum. However, RBN showed no differences for hunger and satiety in the ventral striatum and greater activation in the dorsal caudate when fed compared to hungry. This suggests RBN may be less sensitive to reward when hungry but do not devalue reward when satiated, indicating altered metabolic modulation of self-regulatory control. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Bulimia Nervosa , Estriado Ventral , Feminino , Humanos , Fome , Imageamento por Ressonância Magnética , Recompensa , Estriado Ventral/diagnóstico por imagem
3.
Am J Psychiatry ; 177(7): 601-610, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32160766

RESUMO

OBJECTIVE: Anorexia nervosa has the highest mortality rate of any psychiatric condition, yet the pathophysiology of this disorder and its primary symptom, extreme dietary restriction, remains poorly understood. In states of hunger relative to satiety, the rewarding value of food stimuli normally increases to promote eating, yet individuals with anorexia nervosa avoid food despite emaciation. This study's aim was to examine potential neural insensitivity to these effects of hunger in anorexia nervosa. METHODS: At two scanning sessions scheduled 24 hours apart, one after a 16-hour fast and one after a standardized meal, 26 women who were in remission from anorexia nervosa (to avoid the confounding effects of malnutrition) and 22 matched control women received tastes of sucrose solution or ionic water while functional MRI data were acquired. Within a network of interest responsible for food valuation and transforming taste signals into motivation to eat, the authors compared groups across conditions on blood-oxygen-level-dependent (BOLD) signal and task-based functional connectivity. RESULTS: Participants in the two groups had similar BOLD responses to sucrose and water tastants. A group-by-condition interaction in the ventral caudal putamen indicated that hunger had opposite effects on tastant response in the control group and the remitted anorexia nervosa group, with an increase and a decrease, respectively, in BOLD response when hungry. Hunger had a similar opposite effect on insula-to-ventral caudal putamen functional connectivity in the remitted anorexia nervosa group compared with the control group. Exploratory analyses indicated that lower caudate response to tastants when hungry was associated with higher scores on harm avoidance among participants in the remitted anorexia nervosa group. CONCLUSIONS: Reduced recruitment of neural circuitry that translates taste stimulation to motivated eating behavior when hungry may facilitate food avoidance and prolonged periods of extremely restricted food intake in anorexia nervosa.


Assuntos
Anorexia Nervosa/fisiopatologia , Núcleo Caudado/fisiopatologia , Córtex Cerebral/fisiopatologia , Fome/fisiologia , Putamen/fisiopatologia , Paladar/fisiologia , Adulto , Estudos de Casos e Controles , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Vias Neurais/fisiopatologia , Indução de Remissão , Adulto Jovem
4.
Neuropsychopharmacology ; 44(7): 1265-1273, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30840983

RESUMO

Bulimia nervosa (BN) is characterized by dysregulated intake of food, which may indicate homeostatic imbalance. Critically important for homeostatic regulation is interoception, or the sensing and processing of body-relevant information. A well-documented link between avoidance of unpleasant body sensations and BN symptoms suggests that aversive interoceptive experiences may be particularly relevant to BN pathophysiology. This study examined whether individuals with a history of BN show aberrant neural processing of aversive interoceptive stimuli. Using a cued inspiratory breathing load paradigm, we compared women remitted from BN (RBN; n = 24; to reduce the confounding effects of active bulimic symptoms) and control women (CW; n = 25). During breathing load anticipation, the RBN group, relative to CW, showed increased activation in mid-insula, superior frontal gyrus, putamen, dorsal anterior cingulate, posterior cingulate, and amygdala. However, over the course of the aversive experience, neural activation in RBN relative to CW showed an aberrant decline in most of these regions. Exploratory analyses indicated that greater activation during breathing load anticipation was associated with past bulimic symptom severity and the duration of symptom remission. An exaggerated anticipatory response and an abnormally decreasing response during aversive homeostatic perturbations may promote hallmark bulimic behaviors-binge eating, dietary restriction, and purging. Our findings support a role for homeostatic instability in BN, and these altered patterns of brain activation may serve as novel targets for pharmacological, neuromodulatory, and behavioral interventions.


Assuntos
Antecipação Psicológica/fisiologia , Encéfalo/fisiopatologia , Bulimia Nervosa/fisiopatologia , Bulimia Nervosa/psicologia , Interocepção/fisiologia , Estresse Psicológico/fisiopatologia , Adulto , Mapeamento Encefálico , Bulimia Nervosa/complicações , Feminino , Humanos , Inalação , Imageamento por Ressonância Magnética , Estresse Psicológico/complicações , Adulto Jovem
5.
Artigo em Inglês | MEDLINE | ID: mdl-29043085

RESUMO

BACKGROUND: There is little effective psychopharmacological treatment for individuals with eating disorders who struggle with pervasive, severe affective and behavioral dysregulation. METHODS: This pilot open series evaluated lamotrigine, a mood stabilizer, in the treatment of patients with eating disorders who did not respond adequately to antidepressant medications. Nine women with anorexia nervosa- or bulimia nervosa-spectrum eating disorders in partial hospital or intensive outpatient dialectical behavior therapy (DBT)-based eating disorder treatment took lamotrigine for 147 ± 79 days (mean final dose = 161.1 ± 48.6 mg/day). Participants completed standardized self-report measures of emotion dysregulation and impulsivity after lamotrigine initiation and approximately biweekly thereafter. Mood and eating disorder symptomatology were measured at lamotrigine initiation and at time of final assessment. RESULTS: Lamotrigine and concurrent DBT were associated with large reductions in self-reported affective and behavioral dysregulation (ps < 0.01). Eating disorder and mood symptoms decreased moderately. CONCLUSIONS: Although our findings are limited by the confounds inherent in an open series, lamotrigine showed initial promise in reducing emotional instability and behavioral impulsivity in severely dysregulated eating-disordered patients. These preliminary results support further investigation of lamotrigine for eating disorders in rigorous controlled trials.

6.
Front Nutr ; 4: 32, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28770207

RESUMO

The etiology of pathological eating in anorexia nervosa (AN) remains poorly understood. Cerebral blood flow (CBF) is an indirect marker of neuronal function. In healthy adults, fasting increases CBF, reflecting increased delivery of oxygen and glucose to support brain metabolism. This study investigated whether women remitted from restricting-type AN (RAN) have altered CBF in response to hunger that may indicate homeostatic dysregulation contributing to their ability to restrict food. We compared resting CBF measured with pulsed arterial spin labeling in 21 RAN and 16 healthy comparison women (CW) when hungry (after a 16-h fast) and after a meal. Only remitted subjects were examined to avoid the confounding effects of malnutrition on brain function. Compared to CW, RAN demonstrated a reduced difference in the Hungry - Fed CBF contrast in the right ventral striatum, right subgenual anterior cingulate cortex (pcorr < 0.05) and left posterior insula (punc < 0.05); RAN had decreased CBF when hungry versus fed, whereas CW had increased CBF when hungry versus fed. Moreover, decreased CBF when hungry in the left insula was associated with greater hunger ratings on the fasted day for RAN. This represents the first study to show that women remitted from AN have aberrant resting neurovascular function in homeostatic neural circuitry in response to hunger. Regions involved in homeostatic regulation showed group differences in the Hungry - Fed contrast, suggesting altered cellular energy metabolism in this circuitry that may reduce motivation to eat.

7.
J Abnorm Psychol ; 126(5): 519-530, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28691842

RESUMO

Individuals with bulimia nervosa (BN) engage in episodes of binge eating, marked by loss of control and eating despite fullness. Does altered reward and metabolic state contribute to BN pathophysiology? Normally, hunger increases (and satiety decreases) reward salience to regulate eating. We investigated whether BN is associated with an abnormal response in a neural circuit involved in translating taste signals into motivated behavior, when hungry and fed. Twenty-six women remitted from BN (RBN) and 22 control women (CW) were administered water and sucrose during 2 counterbalanced fMRI visits, following a 16-hr fast or a standardized breakfast. Significant Group × Condition interactions were found in the left putamen, insula, and amygdala. Post hoc analyses revealed CW were significantly more responsive to taste stimuli when hungry versus fed in the left putamen and amygdala. In contrast, RBN response did not differ between conditions. Further, RBN had greater activation in the left amygdala compared with CW when fed. Findings suggest that RBN neural response to rewarding stimuli may not be modulated by metabolic state. Data raise the possibility that disinhibited eating in BN could result from a failure to devalue food reward when fed, resulting in an exaggerated response. (PsycINFO Database Record


Assuntos
Bulimia Nervosa/fisiopatologia , Córtex Cerebral/fisiologia , Fome/fisiologia , Sistema Límbico/fisiologia , Resposta de Saciedade/fisiologia , Percepção Gustatória/fisiologia , Adulto , Estudos de Casos e Controles , Feminino , Giro do Cíngulo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Recompensa , Estriado Ventral/fisiologia , Adulto Jovem
8.
Int J Eat Disord ; 50(5): 593-596, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27753106

RESUMO

OBJECTIVE: Individuals with anorexia nervosa (AN) have anxious and inhibited temperaments with high concern for consequences. Studies using either positron emission tomography (PET) or functional magnetic resonance imaging (fMRI) suggest involvement of the middle and dorsal caudate (DC) in individuals recovered (REC) from AN. For example, dopamine (DA) D2/D3 receptor binding in the middle caudate and DC was associated with anxiety and harm avoidance, and blood-oxygen-level-dependent (BOLD) response in the DC was positively related to trait anxiety. It has not been shown yet whether BOLD response in individuals REC from AN was related to DA function. METHODS: Post-hoc correlation analyses between the PET and fMRI studies by correlating D2/D3 binding in striatal regions and BOLD signal in the anteroventral striatum (AVS) and DC for wins and losses respectively in 12 individuals REC from AN. RESULTS: Individuals REC from AN with the greatest BOLD response in the DC in a monetary choice task had higher middle caudate D2/D3 binding, and greater anxiety and/or harm avoidance. DISCUSSION: Though preliminary, these findings suggest that increased dorsal striatal D2/D3 binding is associated with enhanced cognitive response to feedback, potentially related to anxious anticipation of consequences. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:593-596).


Assuntos
Anorexia Nervosa/psicologia , Dopamina/metabolismo , Imagem Multimodal/métodos , Receptores de Dopamina D2/metabolismo , Adulto , Feminino , Humanos , Masculino , Recompensa
9.
Biol Psychiatry ; 77(7): 642-52, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25481622

RESUMO

BACKGROUND: Hunger enhances sensitivity to reward, yet individuals with anorexia nervosa (AN) are not motivated to eat when starved. This study investigated brain response to rewards during hunger and satiated states to examine whether diminished response to reward could underlie food restriction in AN. METHODS: Using a delay discounting monetary decision task known to discriminate brain regions contributing to processing of immediate rewards and cognitive control important for decision making regarding future rewards, we compared 23 women remitted from AN (RAN group; to reduce the confounding effects of starvation) with 17 healthy comparison women (CW group). Monetary rewards were used because the rewarding value of food may be confounded by anxiety in AN. RESULTS: Interactions of Group (RAN, CW) × Visit (hunger, satiety) revealed that, for the CW group, hunger significantly increased activation in reward salience circuitry (ventral striatum, dorsal caudate, anterior cingulate cortex) during processing of immediate reward, whereas satiety increased activation in cognitive control circuitry (ventrolateral prefrontal cortex, insula) during decision making. In contrast, brain response in reward and cognitive neurocircuitry did not differ during hunger and satiety in the RAN group. A main effect of group revealed elevated response in the middle frontal gyrus for the RAN group compared with the CW group. CONCLUSIONS: Women remitted from AN failed to increase activation of reward valuation circuitry when hungry and showed elevated response in cognitive control circuitry independent of metabolic state. Decreased sensitivity to the motivational drive of hunger may explain the ability of individuals with AN to restrict food when emaciated. Difficulties in valuating emotional salience may contribute to inabilities to appreciate the risks inherent in this disorder.


Assuntos
Anorexia Nervosa/fisiopatologia , Anorexia Nervosa/psicologia , Encéfalo/fisiopatologia , Motivação/fisiologia , Recompensa , Adulto , Mapeamento Encefálico , Desvalorização pelo Atraso/fisiologia , Função Executiva/fisiologia , Feminino , Humanos , Fome , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Adulto Jovem
10.
Front Behav Neurosci ; 8: 410, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25538579

RESUMO

The primary defining characteristic of a diagnosis of an eating disorder (ED) is the "disturbance of eating or eating-related behavior that results in the altered consumption or absorption of food" (DSM V; American Psychiatric Association, 2013). There is a spectrum, ranging from those who severely restrict eating and become emaciated on one end to those who binge and overconsume, usually accompanied by some form of compensatory behaviors, on the other. How can we understand reasons for such extremes of food consummatory behaviors? Recent work on obesity and substance use disorders has identified behaviors and neural pathways that play a powerful role in human consummatory behaviors. That is, corticostriatal limbic and dorsal cognitive neural circuitry can make drugs and food rewarding, but also engage self-control mechanisms that may inhibit their use. Importantly, there is considerable evidence that alterations of these systems also occur in ED. This paper explores the hypothesis that an altered balance of reward and inhibition contributes to altered extremes of response to salient stimuli, such as food. We will review recent studies that show altered sensitivity to reward and punishment in ED, with evidence of altered activity in corticostriatal and insula processes with respect to monetary gains or losses, and tastes of palatable foods. We will also discuss evidence for a spectrum of extremes of inhibition and dysregulation behaviors in ED supported by studies suggesting that this is related to top-down self-control mechanisms. The lack of a mechanistic understanding of ED has thwarted efforts for evidence-based approaches to develop interventions. Understanding how ED behavior is encoded in neural circuits would provide a foundation for developing more specific and effective treatment approaches.

11.
Biol Psychiatry ; 73(9): 836-42, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23380716

RESUMO

Is starvation in anorexia nervosa (AN) or overeating in bulimia nervosa (BN) a form of addiction? Alternatively, why are individuals with BN more vulnerable and individuals with AN protected from substance abuse? Such questions have been generated by recent studies suggesting that there are overlapping neural circuits for foods and drugs of abuse. To determine whether a shared neurobiology contributes to eating disorders and substance abuse, this review focused on imaging studies that investigated response to tastes of food and tasks designed to characterize reward and behavioral inhibition in AN and BN. BN and those with substance abuse disorders may share dopamine D2 receptor-related vulnerabilities, and opposite findings may contribute to "protection" from substance abuse in AN. Moreover, imaging studies provide insights into executive corticostriatal processes related to extraordinary inhibition and self-control in AN and diminished inhibitory self-control in BN that may influence the rewarding aspect of palatable foods and likely other consummatory behaviors. AN and BN tend to have premorbid traits, such as perfectionism and anxiety that make them vulnerable to using extremes of food ingestion, which serve to reduce negative mood states. Dysregulation within and/or between limbic and executive corticostriatal circuits contributes to such symptoms. Limited data support the hypothesis that reward and inhibitory processes may contribute to symptoms in eating disorders and addictive disorders, but little is known about the molecular biology of such mechanisms in terms of shared or independent processes.


Assuntos
Anorexia Nervosa/fisiopatologia , Comportamento Aditivo/fisiopatologia , Encéfalo/fisiopatologia , Bulimia Nervosa/fisiopatologia , Ingestão de Alimentos/fisiologia , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Recompensa
12.
Trends Neurosci ; 36(2): 110-20, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23333342

RESUMO

Individuals with anorexia nervosa (AN) engage in relentless restrictive eating and often become severely emaciated. Because there are no proven treatments, AN has high rates of relapse, chronicity, and death. Those with AN tend to have childhood temperament and personality traits, such as anxiety, obsessions, and perfectionism, which may reflect neurobiological risk factors for developing AN. Restricted eating may be a means of reducing negative mood caused by skewed interactions between serotonin aversive or inhibitory and dopamine reward systems. Brain imaging studies suggest that altered eating is a consequence of dysregulated reward and/or awareness of homeostatic needs, perhaps related to enhanced executive ability to inhibit incentive motivational drives. An understanding of the neurobiology of this disorder is likely to be important for developing more effective treatments.


Assuntos
Anorexia Nervosa/fisiopatologia , Encéfalo/fisiopatologia , Anorexia Nervosa/psicologia , Humanos
13.
Psychiatry Res ; 211(2): 160-8, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23154100

RESUMO

Individuals with anorexia nervosa (AN) and bulimia nervosa (BN) have alterations of measures of serotonin (5-HT) and dopamine (DA) function, which persist after long-term recovery and are associated with elevated harm avoidance (HA), a measure of anxiety and behavioral inhibition. Based on theories that 5-HT is an aversive motivational system that may oppose a DA-related appetitive system, we explored interactions of positron emission tomography (PET) radioligand measures that reflect portions of these systems. Twenty-seven individuals recovered (REC) from eating disorders (EDs) (7 AN-BN, 11 AN, 9 BN) and nine control women (CW) were analyzed for correlations between [(11)C]McN5652 and [(11)C]raclopride binding. There was a significant positive correlation between [(11)C]McN5652 binding potential (BP(non displaceable(ND))) and [(11)C]Raclopride BP(ND) for the dorsal caudate, antero-ventral striatum (AVS), middle caudate, and ventral and dorsal putamen. No significant correlations were found in CW. [(11)C]Raclopride BP(ND), but not [(11)C]McN5652 BP(ND), was significantly related to HA in REC EDs. A linear regression analysis showed that the interaction between [(11)C]McN5652 BP(ND) and [(11)C]raclopride BP(ND) in the dorsal putamen significantly predicted HA. This is the first study using PET and the radioligands [(11)C]McN5652 and [(11)C]raclopride to show a direct relationship between 5-HT transporter and striatal DA D2/D3 receptor binding in humans, supporting the possibility that 5-HT and DA interactions contribute to HA behaviors in EDs.


Assuntos
Anorexia Nervosa/metabolismo , Bulimia Nervosa/metabolismo , Neuroimagem Funcional , Redução do Dano , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Adolescente , Adulto , Anorexia Nervosa/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Bulimia Nervosa/diagnóstico por imagem , Estudos de Casos e Controles , Antagonistas de Dopamina/análise , Feminino , Humanos , Isoquinolinas/análise , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Racloprida/análise , Ensaio Radioligante , Antagonistas da Serotonina/análise
14.
Int J Eat Disord ; 45(2): 263-71, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21541980

RESUMO

OBJECTIVE: Genetic, pharmacologic, and physiological data suggest that individuals with anorexia nervosa (AN) have altered striatal dopamine (DA) function. METHOD: We used an amphetamine challenge and positron emission tomography [(11) C]raclopride paradigm to explore DA striatal transmission in 10 recovered (REC) AN compared with 9 control women (CW). RESULTS: REC AN and CW were similar for baseline, postamphetamine [(11) C]raclopride binding potential (BP(ND) ) and change (Δ) in BP(ND) for all regions. In CW, ventral striatum Δ BP(ND) was associated with euphoria (r = -0.76; p = 0.03), which was not found for REC AN. Instead, REC AN showed a significant relationship between anxiety and Δ BP(ND) in the precommissural dorsal caudate (r = -0.62, p = 0.05). DISCUSSION: REC AN have a positive association between endogenous DA release and anxiety in the dorsal caudate. This finding could explain why food-related DA release produces anxiety in AN, whereas feeding is pleasurable in healthy participants.


Assuntos
Anfetamina/farmacologia , Anorexia Nervosa/psicologia , Ansiedade/metabolismo , Corpo Estriado/metabolismo , Dopaminérgicos/farmacologia , Dopamina/metabolismo , Adulto , Anorexia Nervosa/diagnóstico por imagem , Anorexia Nervosa/metabolismo , Ansiedade/diagnóstico por imagem , Ansiedade/psicologia , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/efeitos dos fármacos , Euforia/efeitos dos fármacos , Euforia/fisiologia , Feminino , Humanos , Cintilografia
16.
Curr Top Behav Neurosci ; 6: 59-79, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21243470

RESUMO

Anorexia nervosa (AN) and bulimia nervosa (BN) are disorders characterized by aberrant patterns of feeding behavior, weight regulation, and disturbances in attitudes and perceptions toward body weight and shape. Several lines of evidence nominate disturbances of serotonin (5-HT) pathways as playing a role in the pathogenesis and pathophysiology of AN and BN. For example, 5-HT pathways are known to contribute to the modulation of a range of behaviors commonly seen in individuals with AN and BN. New technology using brain imaging with radioligands offers the potential for understanding previously inaccessible brain 5-HT neurotransmitter function and its dynamic relationship with human behaviors. Recent studies using positron emission tomography and single photon emission computed tomography with 5-HT-specific radioligands have consistently shown 5-HT(1A) and 5-HT(2A) receptor and 5-HT transporter alterations in AN and BN in cortical and limbic structures, which may be related to anxiety, behavioral inhibition, and body image distortions. These disturbances are present when subjects are ill and persist after recovery, suggesting that these may be traits that are independent of the state of the illness. Effective treatments for AN and BN have been elusive. A better understanding of neurobiology is likely to be important for developing specific and more powerful therapies for these often chronic and deadly disorders.


Assuntos
Encéfalo/metabolismo , Transtornos da Alimentação e da Ingestão de Alimentos/metabolismo , Neuroimagem , Serotonina/metabolismo , Encéfalo/diagnóstico por imagem , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico por imagem , Humanos , Tomografia por Emissão de Pósitrons , Receptor 5-HT1A de Serotonina/metabolismo , Receptor 5-HT2A de Serotonina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único
17.
Int J Eat Disord ; 44(6): 477-87, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20872754

RESUMO

OBJECTIVE: Because altered serotonin (5-HT) function appears to persist after recovery from bulimia nervosa (RBN), we investigated the 5-HT(1A) receptor, which could contribute to regulation of appetite, mood, impulse control, or the response to antidepressants. METHOD: Thirteen RBN individuals were compared to 21 healthy control women (CW) using positron emission tomography and [carbonyl-(11)C]WAY100635 ([(11)C]WAY). RESULTS: RBN had a 23-34% elevation of [(11)C]WAY binding potential (BP)(P) in subgenual cingulate, mesial temporal, and parietal regions after adjustments for multiple comparisons. For CW, [(11)C]WAY BP(P) was related negatively to novelty seeking, whereas for RBN, [(11)C]WAY BP(P) was related positively to harm avoidance and negatively related to sensation seeking. DISCUSSION: Alterations of 5-HT(1A) receptor function may provide new insight into efficacy of 5-HT medication in BN, as well as symptoms such as the ability to inhibit or self-control the expression of behaviors related to stimulus seeking, aggression, and impulsivity.


Assuntos
Encéfalo/diagnóstico por imagem , Bulimia Nervosa/diagnóstico por imagem , Inibição Psicológica , Receptor 5-HT1A de Serotonina/metabolismo , Recuperação de Função Fisiológica , Adulto , Encéfalo/metabolismo , Bulimia Nervosa/metabolismo , Feminino , Humanos , Cintilografia
18.
Int J Eat Disord ; 43(4): 289-94, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19434606

RESUMO

OBJECTIVE: It is possible that disturbances of systems modulating reward may contribute to a vulnerability to develop an eating disorder. METHOD: This hypothesis was tested by assessing functional magnetic resonance brain imaging response to a monetary reward task known to activate the anterior ventral striatum (AVS), a region implicated in motivational aspects toward stimuli. To avoid the confounding effects of malnutrition, 10 women who had recovered from bulimia nervosa (BN) were compared with 10 healthy comparison women (CW). RESULTS: For the AVS, CW distinguished positive and negative feedback, whereas recovered BN women had similar responses to both conditions. In addition, these groups had similar patterns of findings for the dorsal caudate. DISCUSSION: We have previously shown that individuals recovered from anorexia nervosa (AN) also had altered striatal responses and difficulties in differentiating positive and negative feedback. Thus BN and AN individuals may share a difficulty in discriminating the emotional significance of a stimulus.


Assuntos
Gânglios da Base/fisiopatologia , Bulimia Nervosa/fisiopatologia , Bulimia Nervosa/terapia , Imageamento por Ressonância Magnética , Motivação , Recompensa , Adulto , Mapeamento Encefálico , Emoções/fisiologia , Retroalimentação Psicológica/fisiologia , Feminino , Humanos , Valores de Referência , Adulto Jovem
19.
Neuropsychopharmacology ; 33(3): 513-23, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17487228

RESUMO

Anorexia nervosa (AN) is an illness characterized by aversion to ingestion of normally palatable foods. We examined whether there is a primary disturbance of taste processing and experience of pleasure using a sucrose/water task in conjunction with functional magnetic resonance imaging (fMRI). To avoid confounding effects of illness, 16 women recovered from restricting-type AN were compared to 16 control women (CW). We used a region of interest-based fMRI approach to test the idea that individuals with AN have differential neural activation in primary and secondary taste cortical regions after sucrose and water administration. Compared to CW, individuals recovered from AN showed a significantly lower neural activation of the insula, including the primary cortical taste region, and ventral and dorsal striatum to both sucrose and water. In addition, insular neural activity correlated with pleasantness ratings for sucrose in CW, but not in AN subjects. Altered taste processing may occur in AN, based on differences in activity in insular-striatal circuits. These data provide the first evidence that individuals with AN process taste stimuli differently than controls, based on differences in neural activation patterns.


Assuntos
Anorexia Nervosa/fisiopatologia , Anorexia Nervosa/psicologia , Córtex Cerebral/fisiopatologia , Paladar/fisiologia , Adulto , Ansiedade/psicologia , Índice de Massa Corporal , Carboidratos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Escalas de Graduação Psiquiátrica , Água
20.
Am J Psychiatry ; 164(12): 1842-9, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18056239

RESUMO

OBJECTIVE: Individuals with anorexia nervosa are known to be ascetic and able to sustain self-denial of food as well as most comforts and pleasures in life. Building on previous findings of altered striatal dopamine binding in anorexia nervosa, the authors sought to assess the response of the anterior ventral striatum to reward and loss in this disorder. METHOD: Striatal responses to a simple monetary reward task were investigated using event-related functional magnetic resonance imaging. To avoid the confounding effects of malnutrition, the authors compared 13 healthy comparison women and 13 women who had recovered from restricting-type anorexia nervosa and had 1 year of normal weight and regular menstrual cycles, without binge eating or purging. RESULTS: Recovered women showed greater hemodynamic activation in the caudate than comparison women. Only the recovered women showed a significant positive relationship between trait anxiety and the percentage change in hemodynamic signal in the caudate during either wins or losses. In contrast, in the anterior ventral striatum, comparison women distinguished positive and negative feedback, whereas recovered women had similar responses to both conditions. CONCLUSIONS: Individuals who have recovered from anorexia nervosa may have difficulties in differentiating positive and negative feedback. The exaggerated activation of the caudate, a region involved in linking action to outcome, may constitute an attempt at "strategic" (as opposed to hedonic) means of responding to reward stimuli. The authors hypothesize that individuals with anorexia nervosa have an imbalance in information processing, with impaired ability to identify the emotional significance of a stimulus but increased traffic in neurocircuits concerned with planning and consequences.


Assuntos
Anorexia Nervosa/diagnóstico , Gânglios da Base/fisiologia , Recompensa , Adulto , Anorexia Nervosa/fisiopatologia , Anorexia Nervosa/psicologia , Índice de Massa Corporal , Peso Corporal , Mapeamento Encefálico , Núcleo Caudado/irrigação sanguínea , Núcleo Caudado/fisiologia , Discriminação Psicológica/fisiologia , Potenciais Evocados/fisiologia , Retroalimentação/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Jogo de Azar/psicologia , Jogos Experimentais , Hemodinâmica/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética/estatística & dados numéricos , Estado Nutricional , Oxigênio/sangue , Resultado do Tratamento
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