Brain support cells tied to weaker problem-solving in epilepsy

Under a microscope, the cells look like small stars. They are immature astroglia, support cells of the brain, and they were taken from people who were about to have surgery for severe epilepsy. Their number, the researchers found, climbs with age, and it is linked to a loss of what scientists call fluid intelligence: the ability to solve problems you have never met before.

For a long time, astroglia were seen as the brain's support staff, the cells that help neurons communicate and keep the surroundings healthy. Studying them in relation to thinking was hard. Brain scans such as electroencephalography and magnetic resonance imaging cannot resolve individual cells, and tissue from living patients is rarely available. Most earlier work relied on animals or on indirect measures of gene activity. This time, the team at USC (the University of Southern California) had a rare opportunity: tissue from 29 patients with mesial temporal lobe epilepsy, taken from the hippocampus, the region involved in learning and memory.

Before surgery, each patient completed tests of reasoning, memory, attention, language and fine motor coordination. After surgery, the researchers counted the immature astroglia in selected areas of the hippocampus and compared those counts with the test results. Older patients tended to have more abnormal immature astroglia, and higher numbers of these cells were associated with poorer performance on fluid intelligence tests. Fluid intelligence declines with age, and it is also impaired in Parkinson's disease, frontotemporal dementia and multiple sclerosis, which makes the link worth watching beyond epilepsy. The study's first author, Aswathy Ammothumkandy, put it plainly: astroglia could be a shared target for accelerated cognitive decline in people with epilepsy, as well as for seizure control.

The limits are clear. The study shows an association in 29 people, and the team says more research is needed to determine whether abnormal immature astroglia contribute directly to the decline. Ammothumkandy is now looking for molecular differences in these cells by comparing samples from people with epilepsy with control samples, in order to find ways to restore them to a healthier state. Future work might also test neuromodulation, which uses electrical or magnetic stimulation to change nervous system activity, as a way to boost healthy astroglia function.

For patients, nothing changes yet: no treatment has been developed or tested on the basis of this work, and the sources give no timeline. What it does change is the map for drug developers. The researchers note that astroglia are not a major focus of drug development today, and this study could change that. If a drug target emerges from the molecular work, it could eventually be tested first in people with epilepsy, and then, the researchers suggest, its relevance could extend well beyond that group to anyone worried about slower thinking as they age.