byUniversity of North Carolina at Chapel Hill School of Medicine

Credit:Neuron(2025). DOI: 10.1016/j.neuron.2025.02.015

Alzheimer's disease not only robs people of their memory but also affects mood, often causing anxiety and depression. Until now, scientists haven't fully understood how these symptoms are connected in the brain.

A new studypublishedinNeuron, led by Juan Song, Ph.D. from UNC's School of Medicine, sheds light on how Alzheimer's disease affects the brain. The findings could lead to new forms of therapy.

The study focused on two distinct groups of brain cells in a region called the supramammillary nucleus (SuM) located in the posterior hypothalamus—a small region deep in the brain. One group helps regulate memory, while the other influencesemotional responses.

While examining Alzheimer's model mice, researchers discovered these twocircuitsdo not function properly, but when the team used light-based stimulation to activate each pathway, they were able to restore memory or emotional function separately.

"We were surprised that by selectively activating each pathway, we were able to restore either memory or mood in Alzheimer's-model mice," said Song, senior author. "This level of precision in how a single brain region contributes to two very different symptoms—cognitive declineand anxiety or depression—was unexpected and highlights an exciting new avenue for targeted therapies," she said.

Most therapies focus mainly on slowing memory decline, but patients also struggle with anxiety and depression, which greatly affect quality of life. By uncovering specific brain circuits that control memory andmoodseparately, researchers say this new discovery opens the door to future treatments designed to target both symptoms at once.

"This could mean moving toward more personalized, circuit-based therapies that not only preservememorybut also improve emotional well-being, helping patients and families manage the full spectrum of challenges that come with Alzheimer's," said Song.

More information: Lei Han et al, Single-cell spatial transcriptomic atlas of the whole mouse brain, Neuron (2025). DOI: 10.1016/j.neuron.2025.02.015 Journal information: Neuron

Provided by University of North Carolina at Chapel Hill School of Medicine