Neural Representations of Food-Related Attributes in the Human Orbitofrontal Cortex during Choice Deliberation in Anorexia Nervosa

Neuroanatomical associations with autistic characteristics in those with acute anorexia nervosa and weight-restored individuals

Common neuroanatomical regions are associated with both states of anorexia nervosa (AN) and autistic characteristics, but restoration of body mass index (BMI) has been associated with decreased presentation of autistic characteristics in some individuals with AN. This study aims to examine neuroanatomical correlates associated with autistic characteristics in those with acute anorexia nervosa (ac-AN) and those previously diagnosed with AN but whose weight has been restored (WR). In total, 183 individuals (healthy controls [HCs] = 67; n[ac-AN] = 68; n[WR] = 48) from the Brain imaging of Emotion And Cognition of adolescents with Anorexia Nervosa (BEACON) study were included, with autistic characteristics determined in both ac-AN and WR individuals (n = 116). To further examine BMI, ac-AN and WR group associations were compared. Random forest regression (RFR) models examined whether autistic characteristics and morphology of the anterior cingulate cortex (ACC), middle frontal gyrus (MFG), and orbitofrontal cortex (OFC) were able to predict future levels of social anhedonia and alexithymia. Group-wise differences were identified within the volume and surface area of the MFG and OFC, which were unrelated to BMI. Autistic characteristics were inversely associated with MFG and ACC volume, with differences in associations between ac-AN and WR groups seen in the surface area of the MFG. RFR models identified moderate-to-weak performance and found that autistic characteristics were not important predictive features in a priori and exploratory models. Findings suggest that the presence of autistic characteristics in those with ac-AN are associated with the volume of the MFG and are unrelated to BMI restoration.

Eating disorder symptoms and emotional arousal modulate food biases during reward learning in females

Food seeking and avoidance engage primary reward systems to drive behavior. It is nevertheless unclear whether innate or learned food biases interact with general reward processing to interfere with goal-directed choice. To this end, we recruited a large non-clinical sample of females with high eating-disorder symptoms ('HED') and a matched sample of females with low eating-disorder symptoms ('LED') to complete a reward-learning task where the calorie content of food stimuli was incidental to the goal of maximizing monetary reward. We find and replicate a low-calorie food bias in HED and a high-calorie food bias in LED, reflecting the strength of pre-experimental food-reward associations. An emotional arousal manipulation shifts this group-dependent bias across individual differences, with interoceptive awareness predicting this change. Reinforcement-learning models further identify distinct cognitive components supporting these group-specific food biases. Our results highlight the influence of reinforcement-based mechanisms and emotional arousal in eliciting potentially maladaptive food-reward associations.

Maladaptive Restrictive Food Choice Behavior in Adolescents With Anorexia Nervosa

OBJECTIVE

Individuals with anorexia nervosa persistently restrict their food intake while often severely underweight. This maladaptive food choice behavior and related decision-making processes have mainly been investigated in adults. It is unknown whether the same decision-making processes drive food choices in adolescents, given their more favorable treatment outcomes. This study investigated maladaptive food choice behavior in adolescents with AN and examined whether they display the same decision-making processes as adults.

METHOD

Adolescents with AN (n = 42) and age-matched controls (n = 42) completed a computer-based food choice task, rating food images for healthiness and tastiness before choosing between two food items.

RESULTS

Adolescents with AN chose high-fat foods less frequently than controls, with food choices more influenced by their perceived "healthiness" and less by their "tastiness" than they did among controls. Relative to controls, adolescents with AN also reported lower overall tastiness ratings and greater habit strength of restrictive eating, which was, however, not related to food choices.

DISCUSSION

Adolescents with AN display the same maladaptive food choice behavior as adults, namely the persistent restriction of high-fat food choices. Their choices were more strongly influenced by the perceived healthiness of a food item, compared to the choices of controls.

Altered value-based decision-making in anorexia nervosa: A systematic review

Alterations in decision-making are considered core to anorexia nervosa (AN) phenomenology and may maintain illness through maladaptive choice behavior. This systematic review (n = 77) aimed to extend prior reviews beyond standard neuropsychological batteries by incorporating novel value-based choice tasks and computational methods. We organize findings across key factors, including: 1) illness state, 2) developmental stage, and 3) AN subtype, and highlight available neuroimaging findings. Differences in decision-making appear consistent during illness, including in weight-restored samples, but not in recovery and not in all domains. Differences are not consistently present in adolescence, although punishment sensitivity may be heightened; AN subtypes are not consistently distinguishable. Overall, decision-making varies by context and is influenced by reward/punishment processing, risk/uncertainty, and flexibility/control. Utilization of computational modeling methods, possibly increasing precision, highlight that, although raw behavior may not differ at recovery, latent decision-making processes appear impacted. Clinical interventions may benefit from consideration of context when working to shape choice behavior and from consideration of latent decision-making processes that influence how choices are made.

A disinhibitory microcircuit of the orbitofrontal cortex mediates cocaine preference in mice

Both clinical and animal studies showed that the impaired functions of the orbitofrontal cortex (OFC) underlie the compulsive drug-seeking behavior of drug addiction. However, the functional changes of the microcircuit in the OFC and the underlying molecular mechanisms in drug addiction remain elusive, and little is known for whether microcircuits in the OFC contributed to drug addiction-related behaviors. Utilizing the cocaine-induced conditioned-place preference model, we found that the malfunction of the microcircuit led to disinhibition in the OFC after cocaine withdrawal. We further showed that enhanced Somatostatin-Parvalbumin (SST-PV) inhibitory synapse strength changed microcircuit function, and SST and PV inhibitory neurons showed opposite contributions to the drug addiction-related behavior of mice. Brevican of the perineuronal nets of PV neurons regulated SST-PV synapse strength, and the knockdown of Brevican alleviated cocaine preference. These results reveal a novel molecular mechanism of the regulation of microcircuit function and a novel circuit mechanism of the OFC in gating cocaine preference.

Functional specialization of medial and lateral orbitofrontal cortex in inferential decision-making

Inferring prospective outcomes and updating behavior are prerequisites for making flexible decisions in the changing world. These abilities are highly associated with the functions of the orbitofrontal cortex (OFC) in humans and animals. The functional specialization of OFC subregions in decision-making has been established in animals. However, the understanding of how human OFC contributes to decision-making remains limited. Therefore, we studied this issue by examining the information representation and functional interactions of human OFC subregions during inference-based decision-making. We found that the medial OFC (mOFC) and lateral OFC (lOFC) collectively represented the inferred outcomes which, however, were context-general coding in the mOFC and context-specific in the lOFC. Furthermore, the mOFC-motor and lOFC-frontoparietal functional connectivity may indicate the motor execution of mOFC and the cognitive control of lOFC during behavioral updating. In conclusion, our findings support the dissociable functional roles of OFC subregions in decision-making.

Computationally Informed Interventions for Targeting Compulsive Behaviors

Compulsive behaviors are central to addiction and obsessive-compulsive disorder and can be understood as a failure of adaptive decision making. Particularly, they can be conceptualized as an imbalance in behavioral control, such that behavior is guided predominantly by learned rather than inferred outcome expectations. Inference is a computational process required for adaptive behavior, and recent work across species has identified the neural circuitry that supports inference-based decision making. This includes the orbitofrontal cortex, which has long been implicated in disorders of compulsive behavior. Inspired by evidence that modulating orbitofrontal cortex activity can alter inference-based behaviors, here we discuss noninvasive approaches to target these circuits in humans. Specifically, we discuss the potential of network-targeted transcranial magnetic stimulation and real-time neurofeedback to modulate the neural underpinnings of inference. Both interventions leverage recent advances in our understanding of the neurocomputational mechanisms of inference-based behavior and may be used to complement current treatment approaches for behavioral disorders.

The potential application of event-related potentials to enhance research on reward processes in eating disorders

OBJECTIVE

Reward-related processes have been posited as key mechanisms underlying the onset and persistence of eating disorders, prompting a growing body of research in this area. Existing studies have primarily utilized self-report, behavioral, and functional magnetic resonance imaging measures to interrogate reward among individuals with eating disorders. However, limitations inherent in each of these methods (e.g., poor temporal resolution) may obscure distinct neurocognitive reward processes, potentially contributing to underdeveloped models of reward dysfunction within eating disorders. The temporal precision of event-related potentials (ERPs), derived from electroencephalography, may thus offer a powerful complementary tool for elucidating the neurocognitive underpinnings of reward. Indeed, a considerable amount of research in other domains of psychopathology (e.g., depression, substance use disorders), as well as studies investigating food reward among non-clinical samples, highlights the utility of ERPs for probing reward processes. However, no study to date has utilized ERPs to directly examine reward functioning in eating disorders.

METHODS

In this paper, we review evidence underscoring the clinical utility of ERP measures of reward, as well as a variety of reward-related tasks that can be used to elicit specific ERP components with demonstrated relevance to reward processing. We then consider the ways in which these tasks/components may be used to help answer a variety of open questions within the eating disorders literature on reward.

RESULTS/DISCUSSION

Given the promise of ERP measures of reward to the field of eating disorders, we ultimately hope to spur and guide research in this currently neglected area.

PUBLIC SIGNIFICANCE

Abnormalities in reward functioning appear to contribute to eating disorders. Event-related potentials (ERPs) offer temporally precise measures of neurocognitive reward processing and thus may be important tools for understanding the relationship between reward and disordered eating. However, research in this area is currently lacking. This paper attempts to facilitate the use of ERPs to study reward among individuals with eating disorders by reviewing the relevant theories and methods.

Glial cells in anorexia

Anorexia is a loss of appetite or an inability to eat and is often associated with eating disorders. However, animal anorexia is physiologically regulated as a part of the life cycle; for instance, during hibernation, migration or incubation. Anorexia nervosa (AN), on the other hand, is a common eating disorder among adolescent females that experience an intense fear of gaining weight due to body image distortion that results in voluntary avoidance of food intake and, thus, severe weight loss. It has been shown that the neurobiology of feeding extends beyond the hypothalamus. The prefrontal cortex (PFC) is involved in food choice and body image perception, both relevant in AN. However, little is known about the neurobiology of AN, and the lack of effective treatments justifies the use of animal models. Glial cells, the dominant population of nerve cells in the central nervous system, are key in maintaining brain homeostasis. Accordingly, recent studies suggest that glial function may be compromised by anorexia. In this review, we summarize recent findings about anorexia and glial cells.