Forgetfulness, it turns out, is all in the head.

Scientists have shown that fading memory and clouding judgment, the type that comes with advancing age, show up as lost and altered connections between neurons in the brain. But new experiments suggest an existing drug, known as riluzole and already on the market as a treatment for ALS, may help prevent these changes.

Researchers at The Rockefeller University and The Icahn School of Medicine at Mount Sinai found they could stop normal, age-related memory loss in rats by treating them with riluzole. This treatment, they found, prompted changes known to improve connections, and as a result, communication, between certain neurons within the brain’s hippocampus.

They have found that in many cases, aging involves synaptic changes that decrease synaptic strength, the plasticity of synapses, or both. The fact that riluzole increased the clustering of only the thin, most plastic spines, suggests that its enhancement of memory results from both an increase in synaptic strength and synaptic plasticity, which might explain its therapeutic effectiveness.

In this case, the clusters involved thin spines, a rapidly adaptable type of spine. The riluzole-treated animals had more clustering than the young animals and their untreated peers, who had the least. This discovery led the researchers to speculate that, in general, the aged brain may compensate by increasing clustering. Riluzole appears to enhance this mechanism.