Researchers from France have found that astrocytes do more than support neurons in the central nervous system. They found that the cells may also play a role in neuroplasticity. The study was published in Science.
Astrocytes are the most numerous cell type in the central nervous system (CNS). They fall under a class of cells known as ‘glial cells’ which are non-neuronal cells that do not produce electrical impulses. Until now, neuroscientists thought they primarily worked to support neurons. Some studies, however, have found that they may also have a role in neuroplasticity.
The brain is at its most ‘plastic’ just after birth. It is during this short window that the brain configures its neuronal wiring according to the environment it finds itself in. Once the first configuration has been made, neural circuits for information processing and cognitive development stabilize.
This means that problems that occur during this crucial phase of brain plasticity could have major consequences. For example, in the event of an eye condition that prevents a person from seeing properly, such as strabismus (crossed eyes), the corresponding neural circuits could be permanently set in place, unless treated in time.
Being able to recreate this early period of brain plasticity thus holds promise for treating disorders that are set in motion shortly after birth.
To this end, researchers were inspired by studies from the 1980s that demonstrated how transplanting immature astrocytes into the brain of adult animals could bring about high levels of neuroplasticity.
In the present study, they conducted a series of experiments on mice. To begin, they cultured immature astrocytes from the visual cortex of mice aged between 1 and 3 days old. They then implanted these cells into the primary visual cortex of adult mice. Just like in the studies conducted in the 1980's, they found that the mice transplanted it the immature astrocytes presented an unusually high level of neuroplasticity.
“This study is a reminder that in the neurosciences we must not only focus on neurons. The glial cells, of which the astrocytes are a subtype, regulate most of the brain’s functions. We realized that these cells have active roles. Glial cells are less fragile than neurons and so represent a more accessible means of acting on the brain, ” says Nathalie Rouach, one of the study’s authors.