Neural correlates of cue-induced changes in decision-making distinguish subjects with gambling disorder from healthy controls

A review on exploration-exploitation trade-off in psychiatric disorders

Balancing exploration and exploitation is a crucial aspect of adaptive decision-making, but psychiatric disorders can disrupt this balance in various ways, shedding light on their neurocognitive roots and guiding targeted interventions. In this systematic review, we aimed to delineate potential exploration-exploitation impairments across psychiatric disorders. Through a thorough search on PubMed, we identified forty-six relevant studies employing tasks probing exploration-exploitation balances, which we synthesized to reveal distinct patterns. These disorders are clustered into three categories: addictive patterns, emotional/cognitive disturbances, and neurological (neurodevelopmental and neurodegenerative) disorders. Our findings show that anxiety and mood disorders often enhance exploratory behaviors, while depression impact decision stability and reward sensitivity. In contrast, schizophrenia, OCD (Obsessive-Compulsive Disorder), and ADHD (Attention-Deficit/Hyperactivity Disorder) are characterized by excessive switching and difficulties in balancing exploration and exploitation, leading to impaired learning and adaptability. Additionally, disorders with addictive-like features disrupt optimal decision-making strategies by either heightening exploration or causing maladaptive persistence, thus skewing the balance away from effective decision-making. Individuals exhibiting addiction-like or compulsive behaviors often demonstrate imbalances in the explore-exploit trade-off, resulting in suboptimal decision-making characterized by reduced exploration, flawed foraging strategies, and impulsive or perseverative choices despite adverse outcomes. This suggests that such disorders may originate from dysfunctional foraging processes applied to decision-making. In sum, different patterns of exploration-exploitation balance in different disorders are crucial in understanding the difficulties in learning and decision making of neuropsychiatric disorders. This suggests that such disorders may stem from dysregulated decision-making processes, where uncertainty plays a central role. Dysfunctions in dopaminergic and noradrenergic pathways appear to disrupt the brain's representation of uncertainty, thereby altering exploratory behavior. In sum, the varying patterns of exploration-exploitation balance across different disorders are critical for understanding the challenges in learning and decision-making associated with neuropsychiatric conditions.

A roadmap for transformative translational research on gambling disorder in the UK

The UK has one of the highest rates of recreational gambling in the world. Some vulnerable individuals progressively lose control over gambling and develop at-risk gambling or gambling disorder (GD), characterised by the compulsive pursuit of gambling. GD destroys lives and incurs massive costs to societies, yet only a few treatments are available. Failure to develop a wider range of interventions is in part due to a lack of funding that has slowed progress in the translational research necessary to understand the individual vulnerability to switch from controlled to compulsive gambling. Current preclinical models of GD do not operationalise the key clinical features of the human condition. The so-called "gambling tasks" for non-human mammals almost exclusively assess probabilistic decision-making, which is not real-world gambling. While they have provided insights into the psychological and neural mechanisms involved in the processing of gains and losses, these tasks have failed to capture those underlying real-world gambling and its compulsive manifestation in humans. Here, we highlight the strengths and weaknesses of current gambling-like behaviour tasks and suggest how their translational validity may be improved. We then propose a theoretical framework, the incentive habit theory of GD, which may prove useful for the operationalisation of the biobehavioural mechanisms of GD in preclinical models. We conclude with a list of recommendations for the development of next-generation preclinical models of GD and discuss how modern techniques in animal behavioural experimentation can be deployed in the context of GD preclinical research to bolster the translational pipeline.

Neural cue-reactivity in pathological gambling as evidence for behavioral addiction: a systematic review

Increasing incidence of problem gambling has led to prioritizing the problem from the point of view of public health. Additionally, gambling disorder has been recently classified as a behavioral addiction, with implications for both its diagnosis and treatment. However, the shared neural substrate of addictions, to substances and behavioral, is still discussed. Thus, this systematic review aims to provide up-to-date knowledge from the past five years (2017-2022) concerning the neural correlates of gambling related stimuli (cue-reactivity) on the basis of a previous review (Brevers et al., Cognitive, Affective and Behavioral Neuroscience 18:718-729, 2019). A total of five studies were included in the review. Activation of brain areas related to memory, reward and executive functions could be the underlying mechanism of this behavioral addiction. Specifically, nucleus accumbens and striatum (ventral and dorsal), parahippocampal regions, the right amygdala and several prefrontal cortex regions have systematically been found more active in those subjects exposed to gambling-related cues. Also, the insula could play a pivotal role connecting these three systems in a highly integrated neural network with several implications for reward processing modulation, associative learning and top-down attentional regulation to improve saliency of addiction-related cues. These results are consistent with previous findings on other substance addictions, such as alcohol, tobacco, marijuana or cocaine. The study of neural reactivity to stimuli related to addiction could be useful as a biomarker of the severity of the disorder, the efficacy of the treatment, the risk of relapse, in addition to being an objective criterion to measure the effectiveness of prevention campaigns.