Cerebrum Summer 2021

ADVANCES Notable brain-science findings

A BRAIN-COMPUTER INTERFACE has helped one man with paralysis to quickly write sentences on a computer screen by picturing himself writing the letters by hand. He had two electrode arrays implanted on the surface of his brain in motor areas; as he imagined writing letters, the electrodes’ signals were fed into a software program that first learned which signal stood for which letter and now can translate it, in close to real- time, to text on a screen. This

BY NICKY PENTTILA

A NEW DRUG intended to slow the cognitive decline caused by Alzheimer’s disease was conditionally approved by the US Food and Drug Administration in June. The drug, Aduhelm, reduces the amount of amyloid- beta plaque in the brains of people diagnosed with mild cognitive impairment, but it is less clear that it actually affects their problems with cognition. Under the FDA’s

accelerated approval process, used when a potential drug would fill a serious “unmet medical need,” the drug’s maker, Biogen, is required to continue its research in Stage 4 clinical trials in hopes that it will eventually show a clinical benefit that is greater than its sometimes-serious side effects. l

translation appears to be far faster than current speech- to-text systems and comes close to the speed of the average person who “thumb types” on their phone. l A team of researchers has restored partial VISION to a man who had a form of blindness in which his light- capturing (photoreceptor) cells had died. They used gene therapy to add light-sensitive (optogenetic) proteins to some of his healthy retinal ganglion cells instead, enabling them to respond to amber light. The man wears goggles that scan their field of view, notice any pixels in which the light changes, and then send a pulse of amber light from that pixel into one of his eyes. After seven months of practice, his brain had learned to convert that signal in a way that helps him see lines on a crosswalk and distinguish when there are two or three glasses on a table. l

Seeking to stifle the body’s natural rejection of foreign material like electrode arrays and other brain implants, researchers in Canada have invented a more brain- like material for IMPLANTS as well as a gentler way of inserting them. Their implants are formed using flexible silicone, which bends and moves much like brain matter. The new scaffolding holding these micro-implants is made of sugars, which dissolve and are washed away soon after insertion. In rats, the implants appeared to be accepted more readily and for longer than methods using soft polymers or hydrogel coatings. l

M ore news that regular physical activity (i.e., EXERCISE and PLAY ) may be good for kids comes from an imaging study of nearly 6,000 nine- and ten-year-olds. Those who were active most days for at least an hour at a time showed brain circuitry that was more efficiently organized, flexible, and robust. The study showed that the more physical activity, the bigger the difference when compared with kids who did not move as much. For kids with higher-than-average body mass indexes, which is associated with harmful effects on the same brain circuits, those who were more physically active seemed to be able to offset the effects. These results are correlations based on large data sets, so very suggestive but not direct proof. l

6 DANA FOUNDATION CEREBRUM | Summer 2021

ADUHELM PHOTO: BIOGEN; GIRL AND BRAIN INTERFACE IMAGES: SHUTTERSTOCK

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