FiPhoPHA-A Fiber Photometry Python Package for Post Hoc Analysis.

Fiber photometry is a neuroscience technique that can continuously monitor in vivo fluorescence to assess population neural activity or neuropeptide/transmitter release in freely behaving animals. Despite the widespread adoption of this technique, methods to statistically analyze data in an unbiased, objective, and easily adopted manner are lacking. Various pipelines for data analysis exist, but they are often system specific, are only for preprocessing data, and/or lack usability.

A simple action reduces high-fat diet intake and obesity in mice.

Diets that are high in fat cause overeating and weight gain in multiple species of animals, suggesting that high dietary fat is sufficient to cause obesity. However, high-fat diets are typically provided freely to animals in obesity experiments, so it remains unclear whether high-fat diets would still cause obesity if these diets required more effort to obtain. We hypothesized that unrestricted access to high-fat diets is important for these diets to induce overeating and that requiring mice to perform small amounts of work to obtain a high-fat diet would reduce calorie intake and associated weight gain.

An Island of Reil excitation: Mapping glutamatergic (vGlut1+ and vGlut2+) connections in the medial insular cortex.

The insular cortex is a multifunctional and richly connected region of the cerebral cortex, critical in the neural integration of external stimuli and internal signals. Well-served for this role by a large network of afferent and efferent connections, the mouse insula can be simplified into an anterior, medial and posterior portion. Here we focus on the medial subregion, a once over-looked area that has gained recent attention for its involvement in an array of behaviours.

Potential Differences in Psychedelic Actions Based on Biological Sex.

The resurgence of interest in psychedelics as treatments for psychiatric disorders necessitates a better understanding of potential sex differences in response to these substances. Sex as a biological variable (SABV) has been historically neglected in medical research, posing limits to our understanding of treatment efficacy. Human studies have provided insights into the efficacy of psychedelics across various diagnoses and aspects of cognition, yet sex-specific effects remain unclear, making it difficult to draw strong conclusions about sex-dependent differences in response to psychedelic treatments.

Metabolic sensing in AgRP regulates sucrose preference and dopamine release in the nucleus accumbens.

Hunger increases the motivation for calorie consumption, often at the expense of low-taste appeal. However, the neural mechanisms integrating calorie-sensing with increased motivation for calorie consumption remain unknown. Agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus sense hunger, and the ingestion of caloric solutions promotes dopamine release in the absence of sweet taste perception.

Acute inhibition of hunger-sensing AgRP neurons promotes context-specific learning in mice.

Objective: An environmental context, which reliably predicts food availability, can increase the appetitive food drive within the same environment context. However, hunger is required for the development of such a context-induced feeding (CIF) response, suggesting the neural circuits sensitive to hunger link an internal energy state with a particular environment context. Since Agouti related peptide (AgRP) neurons are activated by energy deficit, we hypothesised that AgRP neurons are both necessary and sufficient to drive CIF.

A paraventricular thalamus to insular cortex glutamatergic projection gates "emotional" stress-induced binge eating in females.

It is well-established that stress and negative affect trigger eating disorder symptoms and that the brains of men and women respond to stress in different ways. Indeed, women suffer disproportionately from emotional or stress-related eating, as well as associated eating disorders such as binge eating disorder. Nevertheless, our understanding of the precise neural circuits driving this maladaptive eating behavior, particularly in women, remains limited.

Rapid, automated, and experimenter-free touchscreen testing reveals reciprocal interactions between cognitive flexibility and activity-based anorexia in female rats.

Anorexia nervosa has among the highest mortality rates of any psychiatric disorder and is characterized by cognitive inflexibility that persists after weight recovery and contributes to the chronic nature of the condition. What remains unknown is whether cognitive inflexibility predisposes individuals to anorexia nervosa, a question that is difficult to address in human studies. Our previous work using the most well-established animal model of anorexia nervosa, known as activity-based anorexia (ABA) identified a neurobiological link between cognitive inflexibility and susceptibility to pathological weight loss in female rats.

Liver-expressed antimicrobial peptide 2 is associated with improved pancreatic insulin secretion in adults with overweight and obesity.

Aims: To examine association of liver-expressed antimicrobial peptide 2 (LEAP2), an endogenous ghrelin antagonist with anorexiant effects, to key cardiometabolic risk factors in people with overweight and obesity.

Methods: In this cross-sectional study, we sought to identify associations between LEAP2 levels and cardiometabolic risk factors, including body composition (dual X-ray absorptiometry), insulin and glucose metabolism (oral and intravenous glucose tolerance tests and hyperinsulinaemic-euglycaemic clamps), plasma lipids and inflammation markers (ELISA and multiplex assays).

Results: In 65 participants with overweight or obesity (63.

Identification of a Stress-Sensitive Anorexigenic Neurocircuit From Medial Prefrontal Cortex to Lateral Hypothalamus.

Background: A greater understanding of how the brain controls appetite is fundamental to developing new approaches for treating diseases characterized by dysfunctional feeding behavior, such as obesity and anorexia nervosa.

Methods: By modeling neural network dynamics related to homeostatic state and body mass index, we identified a novel pathway projecting from the medial prefrontal cortex (mPFC) to the lateral hypothalamus (LH) in humans (n = 53). We then assessed the physiological role and dissected the function of this mPFC-LH circuit in mice.

Hypothalamic effective connectivity at rest is associated with body weight and energy homeostasis.

Hunger and satiety drive eating behaviours via changes in brain function. The hypothalamus is a central component of the brain networks that regulate food intake. Animal research parsed the roles of the lateral hypothalamus (LH) and medial hypothalamus (MH) in hunger and satiety, respectively.

In Vivo Photometry Reveals Insulin and 2-Deoxyglucose Maintain Prolonged Inhibition of VMH Vglut2 Neurons in Male Mice.

The ventromedial hypothalamic (VMH) nucleus is a well-established hub for energy and glucose homeostasis. In particular, VMH neurons are thought to be important for initiating the counterregulatory response to hypoglycemia, and ex vivo electrophysiology and immunohistochemistry data indicate a clear role for VMH neurons in sensing glucose concentration. However, the temporal response of VMH neurons to physiologically relevant changes in glucose availability in vivo has been hampered by a lack of available tools for measuring neuronal activity over time.

Metabolic sensing in AgRP neurons integrates homeostatic state with dopamine signalling in the striatum.

Agouti-related peptide (AgRP) neurons increase motivation for food, however, whether metabolic sensing of homeostatic state in AgRP neurons potentiates motivation by interacting with dopamine reward systems is unexplored. As a model of impaired metabolic-sensing, we used the AgRP-specific deletion of carnitine acetyltransferase () in mice. We hypothesised that metabolic sensing in AgRP neurons is required to increase motivation for food reward by modulating accumbal or striatal dopamine release.

Neurobiology: How to ask a mouse if it's hungry.

Neural circuits influence food intake by responding to interoceptive hunger cues and/or hedonic cues. A new study utilizes a hunger discrimination behavioural task combined with opto- and chemo-genetic manipulation to identify hunger and non-hunger sensing neural circuits driving food intake.

Neural network modelling reveals changes in directional connectivity between cortical and hypothalamic regions with increased BMI.

Background/objectives: Obesity has been ascribed to corticostriatal regions taking control over homeostatic areas. To test this assumption, we applied an effective connectivity approach to reveal the direction of information flow between brain regions and the valence of connections (excitatory versus inhibitory) as a function of increased BMI and homeostatic state.

Subjects/methods: Forty-one participants (21 overweight/obese) underwent two resting-state fMRI scans: after overnight fasting (hunger) and following a standardised meal (satiety).

Endocannabinoid signaling of homeostatic status modulates functional connectivity in reward and salience networks.

Rationale: Endocannabinoids are well poised to regulate crosstalk between energy sensing of hunger and satiety and reward-driven motivation.

Objectives: Here, we aimed to unravel associations between plasma endocannabinoids and brain connectivity in homeostatic and reward circuits across hunger and satiety states.

Methods: Fifteen participants (7 females) underwent two counter-balanced resting-state functional magnetic resonance imaging scans, one after overnight fasting and one after consumption of a standardized filling meal (satiety).

The Hunger Games: Homeostatic State-Dependent Fluctuations in Disinhibition Measured with a Novel Gamified Test Battery.

Food homeostatic states (hunger and satiety) influence the cognitive systems regulating impulsive responses, but the direction and specific mechanisms involved in this effect remain elusive. We examined how fasting, and satiety, affect cognitive mechanisms underpinning disinhibition using a novel framework and a gamified test-battery. Thirty-four participants completed the test-battery measuring three cognitive facets of disinhibition: attentional control, information gathering and monitoring of feedback, across two experimental sessions: one after overnight fasting and another after a standardised meal.

Symptoms of Addictive Eating: What Do Different Health Professions Think?

The symptoms of addictive eating are often debated, with some overlap in symptoms with substance addictions or other disorders such as binge eating disorder. This study explored the levels of agreement with symptoms of addictive eating among different health professions, the conditions they provide advice for, and the population group/s they work with. An online cross-sectional survey was conducted in February-April 2020 including 142 health professionals (87% female, 65% residing in Australia, 28% each working in private practice/hospital settings).

Insulin as a neuroendocrine hormone.

The year 2021 marks 100 years since the discovery of insulin and this Special Issue of the Journal of Neuroendocrinology was conceived as a way to mark that historic breakthrough. The discovery of insulin and its subsequent use in the treatment of diabetes is one of the most striking success stories in biomedical research. From a neuroendocrinology perspective, the recognition that insulin also exerts widespread and varied actions in the brain is more recent, but potentially also of equal importance with relevance for conditions ranging from obesity to dementia.