Human milk is considered the most advantageous source of nourishment for infants. Even though there is no ideal composition of human milk, it still contains a unique combination of components that contribute to brain development. The aim of this review is to provide an overview on the possible correlation of human milk with the neurodevelopment of infants, with a special emphasis on myelination and epigenetic modifications. Research in human milk is a rapidly expanding field and cutting-edge technologies might contribute to identify specific mechanisms underlying the beneficial effects on human milk on neurodevelopment.

Anorexia nervosa (AN) is a psychiatric disorder mainly characterized by extreme hypophagia, severe body weight loss, hyperactivity, and hypothermia. Currently, AN has the highest mortality rate among psychiatric illnesses. Despite decades of research, there is no effective cure for AN nor is there a clear understanding of its etiology. Since a complex interaction between genetic, environmental, social, and cultural factors underlines this disorder, the development of a suitable animal model has been difficult so far. Here, we present our protocol that couples a loss-of-function mouse model to the activity-based anorexia model (ABA), which involves self-imposed starvation in response to exposure to food restriction and exercise. We provide insights into a neural circuit that drives survival in AN and, in contrast to previous protocols, propose a model that mimics the conditions that mainly promote AN in humans, such as increased incidence during adolescence, onset preceded by negative energy balance, and increased compulsive exercise. This protocol will be useful for future studies that aim to identify neuronal populations or brain circuits that promote the onset or long-term maintenance of this devastating eating disorder.

Recent genetic findings have highlighted the importance of metabolic factors in contributing to risk for anorexia nervosa. The treatment of anorexia nervosa, however, has largely not yet attempted to modulate metabolic pathways, given that knowledge and understanding of potential metabolic targets and treatment goals remain limited. In search of potential metabolic mechanisms at play in psychiatric disorders, we look at the brain and beyond, focusing on ketones, related molecules, and nutritional therapies, e.g. the ketogenic diet, highlighting their brain and behavioural effects. The aim of this review is therefore to summarize knowledge on the physiology of ketones and related molecules, as well as evidence on their role on energy balance, brain, and behaviour. We then review the role ketones might have on the pathophysiology of anorexia nervosa, and how the intake of exogenous ketones and ketone precursors might impact on brain and behaviour in anorexia nervosa. We conclude with an hypothesised model explaining the potential role of ketones in the pathophysiology of anorexia nervosa and propose that exogenous ketones and ketone precursors could be an alternative source of brain energy in this illness and deserve further investigation.

As marijuana use during adolescence has been increasing, the need to understand the effects of its long-term use becomes crucial. Previous research suggested that marijuana consumption during adolescence increases the risk of developing mental illnesses, such as schizophrenia, depression, and anxiety. Ghrelin is a peptide produced primarily in the gut and is important for feeding behavior. Recent studies have shown that ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR), play important roles in mediating stress, as well as anxiety and depression-like behaviors in animal models. Here, we investigated the effects of chronic tetrahydrocannabinol (THC) administration during late adolescence (P42–55) in GHSR (GHSR ^−/−) knockout mice and their wild-type littermates in relation to anxiety-like behaviors. We determined that continuous THC exposure during late adolescence did not lead to any significant alterations in the anxiety-like behaviors of adult mice, regardless of genotype, following a prolonged period of no exposure (1 month). These data indicate that in the presence of intact or impaired ghrelin/GHSR signaling, THC exposure during late adolescence has limited if any long-term impact on anxiety-like behaviors in mice.

Neurons and oligodendrocytes are the building blocks of the brain. Neurons form synaptic connections and transmit signals, while oligodendrocytes, including oligodendrocyte precursor cells (OPCs) and their derivatives, are vital for central nervous system maintenance and myelination. The demand for human-specific neuron-oligodendrocyte model systems to study these interactions has grown, yet co-culture protocols remain limited. Recent advancements in the field provide methods for deriving co-cultures of neurons and OPCs from human induced pluripotent stem cells (hiPSC), each with distinct benefits and challenges. This study presents a time-efficient, reproducible method to derive neurons and O4-expressing oligodendrocytes, followed by a straightforward co-culture system that minimizes astrocyte differentiation and ensures robust neuron and oligodendrocyte populations.