neuroscience

A new study sheds light on how the brain adjusts its ‘wiring’ during learning, concluding that different dendritic segments of the same neuron follow different rules for communicating through their connections - synapses. The findings challenge the idea that neurons follow a single learning strategy and offer a new perspective on how the brain learns and adapts its behaviour. The work, carried out in mice, is published in the journal Science.

A set of articles published in Nature and Nature Methods draws a high-resolution map of the structure of and connections between the brain cells of mice. The map is based on data from a single cubic millimetre of brain and includes more than 200,000 cells, around 84,000 neurons and 524 million synaptic connections. Although this is a very small part of the mouse brain, it will help us understand how different types of cells work together.

A multidisciplinary team of researchers in the United States has implanted a paralysed person with a brain-computer interface capable of detecting and decoding finger movements. The system achieved a degree of accuracy that allowed him to play a video game. The results are published in the journal Nature Medicine.

Researchers in China have analysed data from more than 4,500 people and identified 13 proteins linked to brain ageing. In addition, changes in protein concentrations in the blood tend to peak at ages 57, 70 and 78. According to the authors, who publish the results in the journal Nature Aging, these ages may reflect transitions in human brain health at specific ages, and could therefore be important for designing possible interventions in the brain ageing process.

According to a study published in Nature Medicine, deep brain stimulation of the lateral hypothalamus improves walking and promotes recovery in humans and rodents with spinal cord injuries. In humans, the authors tested this technique on two patients who relied on assistive devices and had difficulty walking; both showed improved performance in the ten-meter and six-minute walking tests. Combined with rehabilitation, the patients experienced recovery that persisted even after the deep brain stimulation was turned off.

Until now, memories have been explained by the activity of neurons that respond to learning events and control recall. A study published in Nature changes this theory by showing that non-neuronal cells in the brain called astrocytes - star-shaped cells - also store memories and work in concert with clusters of connected neurons called engrams to regulate the storage and retrieval of memories.

A study describes changes in a woman's brain during and after pregnancy, including a ‘pronounced’ decrease in grey matter volume and cortical thickness, and an increase in ventricular volume and cerebrospinal fluid. Some of the changes are maintained in the postpartum period; others reverse within months. The team performed 26 MRI scans and blood tests on one mother, from pre-conception until two years postpartum, and publish the results in Nature Neurology. 

An international team of researchers has studied 241 brain-damaged people apparently unable to respond to external stimuli. Using techniques such as functional magnetic resonance imaging and electroencephalogram, they have detected signs of brain activity in 25 % of them that, according to the authors, ‘suggest that they may be interacting with the outside world’. The results are published in the journal NEJM. 

A brain study of 23 people with treatment-resistant depression while they listen to classical music has identified the antidepressant mechanisms of this music. Using intracranial recordings and electroencephalogrammes, the researchers concluded that listening to classical music synchronises neuronal oscillations between the auditory cortex - responsible for processing sensory information - and the reward circuit - responsible for processing emotional information. "The improvement of depressive symptoms was not linked to the emotion of the music itself but was correlated with the patient’s level of music enjoyment," says the study published in Cell Reports.

Both sex and gender are associated with distinct networks in the brains of boys and girls, according to an analysis of brain images of 4,757 children in the US. Understanding these neurobiological patterns is important for identifying how sex and gender influence health and for developing specific diagnostic tools, the research team writes in Science Advances.