neuroscience

An article published in Brain Health proposes using the concept of the ‘criticome’ to refer to the sensory, motor, social, cultural and environmental information recorded from pregnancy up to the age of 25, which is the period of greatest brain plasticity. According to the authors, this concept reframes autism, schizophrenia and depression as developmental disorders rather than purely synaptic disorders. Besides, they say this approach would have implications for educational policy, mental health care and screen use, amongst other issues.

The eyes are connected to the brain via the retina, which makes it a potential pathway for brain stimulation. A study published in Cell Reports Physical Science has used contact lenses equipped with a system for transcorneal electrical stimulation to treat depression in animal models of the disorder. Mice fitted with the device showed behavioural improvements, including increased sociability, as well as physiological changes, such as the restoration of altered neural connections. The results were comparable to those obtained with fluoxetine —known commercially as Prozac— administered for three weeks in one of the mouse groups.

The hallucinogen psilocybin, found in certain mushrooms, is being investigated as a treatment for conditions such as depression. A study published in Nature Communications shows that a single 25 mg dose of the compound can produce brain changes lasting up to a month after administration. These were measured using neuroimaging techniques in 28 healthy adults who had never taken psychedelics. In terms of psychological effects, participants showed increased cognitive flexibility, psychological insight, and well-being after one month.

Autism spectrum disorders are often accompanied by social communication difficulties, which are treated through behavioral interventions. A type of transcranial magnetic stimulation, accelerated continuous theta-burst stimulation, has demonstrated efficacy and safety in improving this aspect in a clinical trial published in the BMJ. The trial included 200 children from China (167 boys and 33 girls) aged 4 to 10 with autism spectrum disorder, half of whom had intellectual disabilities. One group of participants received 10 daily sessions targeting the motor cortex over five consecutive days, while the other group received sham sessions. The treated group showed greater improvements in both social communication and language skills for one month following treatment.

A study published in Science analyzed more than 100,000 human neocortical cells from weeks 13 to 23 of gestation, when cortical neurons are generated. The samples came from 26 donors, some with and others without Down syndrome. Using single-cell genomics, they observed how trisomy 21 disrupts the developmental sequence of various types of neurons, which could explain subsequent differences in cognition. A second study in the same journal, which examines the postnatal brains of children with Down syndrome, finds that many of these changes persist into childhood. The authors note that their study will not have short-term clinical applications, but they hope it can be used to develop specific drugs or create gene therapies. 

A US team analyzed the genetic activity of individual brain cells from 15 men and 15 women and found 133 genes that showed consistent differences. Although biological sex explained only a small part of the differences they found when comparing all the brains, variants in many of these genes have been associated with neuropsychiatric and neurodegenerative disorders—such as ADHD, schizophrenia, depression, and Alzheimer's—suggesting that sex differences could play a role in the distinct risk men and women have of developing certain diseases. The authors, however, acknowledge that the sex-related differences in their study could stem from differences in socialization and experience. The results are published in Science.  

Various studies have shown that exercise benefits the brain. Now, an international team has studied in mice how physical activity affects the brain and how these changes influence the effects of exercise. The research, published in Neuron, has shown that physical activity causes brain changes in a region of the hypothalamus involved in how the body uses energy and in regulating blood sugar. If these neurons were blocked immediately after exercise, the animals showed no improvement in endurance or metabolism with training. The authors suggest that activating these neurons may help the body recover faster, allowing other parts, such as the muscles, lungs, and heart, to adapt more quickly to more intense workouts.

The American Psychiatric Association has unveiled the new features of the forthcoming Diagnostic and Statistical Manual of Mental Disorders (DSM) in five articles published in The American Journal of Psychiatry. Among the highlights are the proposed change of name — it will become the Diagnostic and Scientific Manual — and the intention for it to be more dynamic, incorporating biomarkers for diagnosis and integrating the socioeconomic, cultural and environmental determinants of health. According to the authors, the aim is to enable a more personalised and inclusive clinical practice, aligned with scientific rigour. The most recent update was published in 2022 with the DSM-5-TR, and specialists are currently unaware of the date of the next edition, as they reported during a briefing with journalists.

An international team trained 85 people to activate a part of the brain associated with reward and positive expectations, after which they received a hepatitis B vaccine. Overall, those who learned to maintain greater activity in this area showed a greater increase in antibody levels after immunization. According to the authors, the results “suggest that positive thinking could help the brain strengthen the immune system in a non-invasive way.” The work is published in Nature Medicine. 

A research team identified five major phases of brain topology throughout human life—changes in the structure of neural connections—as detailed in an article published in Nature Communications. Using brain images from 3,802 people between the ages of 0 and 90, it defines four turning points around the ages of 9, 32, 66, and 83.