San Francisco: Like a great orchestra, your brain relies on the perfect coordination of many elements to function properly. And if one of those elements is out of sync, it affects the entire ensemble. In Alzheimer’s disease, for instance, damage to specific neurons can alter brainwave rhythms and cause a loss of cognitive functions.

One type of neuron, called inhibitory interneuron, is particularly important for managing brain rhythms. It’s also the research focus of a laboratory led by Jorge Palop, PhD, the assistant investigator at the Gladstone Institutes. In a study published in Neuron, Palop and his collaborators uncovered the therapeutic benefits of genetically improving these interneurons and transplanting them into the brain of a mouse model of Alzheimer’s disease.

Interneurons control complex networks between neurons, allowing them to send signals to one another in a harmonized way. You can think of inhibitory interneurons as orchestra conductors. They create rhythms in the brain to instruct the players — excitatory neurons — when to play and when to stop. An imbalance between these two types of neurons creates disharmony and is seen in multiple neurological and psychiatric disorders, including Alzheimer’s disease, epilepsy, schizophrenia, and autism.

Palop’s previous studies showed that, in mouse models of Alzheimer’s, the inhibitory interneurons do not work properly. So, the rhythms that organize the excitatory cells are disturbed and fail to function harmoniously, causing an imbalance in brain networks. This, in turn, affects memory formation and can lead to epileptic activity, which is often observed in patients with Alzheimer’s disease.

His team found a way to re-engineer inhibitory interneurons to improve their function. They showed that these enhanced interneurons, when transplanted into the abnormal brain of Alzheimer mice, can properly control the activity of excitatory cells and restore brain rhythms.