Electrical Brain Stimulation Boosts Short-Term Memory

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Working memory—the ability to store useful information in the brain for a short time—is a major factor in the cognitive losses associated with aging. These losses may result from disruptions in connectivity between various areas of the brain. But a 2019 study in Nature Neuroscience suggests that brief, noninvasive, painless delivery of small amounts of alternating electrical currents to relevant brain regions may reverse this decline.

Investigators studied 84 adults; half were 20 to 29 years old, and half were 60 to 76 years of age. At baseline, the older group had trouble recalling information as quickly and accurately as the younger participants. Investigators fitted the older group with electrodes embedded in a skull cap, then delivered an alternating current designed to interact with and manipulate brain oscillations. During the 25-minute stimulation, participants performed working memory tasks. (The younger group donned skull caps with electrodes but no current.)

An average of 12 minutes after the stimulation began, the older group’s working memory improved, rising to the levels demonstrated by the younger group. These gains continued after the stimulation period. Electroencephalography showed that the stimulation may increase the interaction and synchronization of some brain wave rhythms, mimicking younger brains.

This study provides the groundwork for interventions for stopping cognitive decline.