For decades, the search for the origins of memory loss has focused almost exclusively on two regions of the brain: the prefrontal cortex and the hippocampus. However, Dr. Tatiana Viena, a new researcher at East Tennessee State University’s Quillen College of Medicine, is shifting the scientific spotlight toward a long-overlooked region that may hold the key to restoring cognitive function: the thalamus.
“The thalamus has been a region that has been overlooked for quite some time now when it comes to memory” Viena explains. “In the past, the field has heavily focused on researching cortical regions, but we know the thalamus is important in modulating both. We are pioneers in understanding the cellular composition of the cells within the midline thalamus, what they do and how they are involved.”
Specifically, Viena’s lab investigates the nucleus reuniens, the largest nucleus of the cognitive midline thalamus. This structure acts as a critical biological “hub,” coordinating the dialogue between the brain’s executive center (the prefrontal cortex) and its memory center (the hippocampus). When this circuit breaks down, the communication required to form and retrieve memories is severed, a hallmark of Alzheimer’s disease.
The Viena Lab uses state-of-the-art technology to observe electrophysiological changes in these pathways in real-time. Using custom-built, 3D-printed “optrodes”, devices that combine electrodes with fiber optics, the lab can precisely manipulate virally targeted neurons in the brain. This approach allows cells to be turned ‘on or off’ with millisecond precision. “We can activate or inactivate specific cells”, Viena says. “This lets us study both gain-of-function and loss-of-function.” This level of control allows the team to pinpoint exactly which cellular populations are failing as memory-related illnesses progress.
The Viena lab also investigates how brain regions coordinate their activity during sleep. By monitoring the brain during “theta” and delta-dominated states”, her lab is identifying how the thalamus manages information flow when the body is at rest. Understanding these sleep-state transitions is vital, as many memory disorders are preceded by disruptions in the brain’s ability to communicate during sleep.
Dr. Viena isn’t just focused on the scientific data; she is also focused on the people. As a researcher from “humble beginnings” who describes her journey as an “uphill battle,” she is dedicated to mentoring the next generation of scientists, particularly those from disadvantaged backgrounds. One of the primary reasons she chose ETSU was the university’s mission of “serving the underserved”.
“The best way to support other individuals that are underserved is by leading by example and providing supporting resources and mentorship,” Viena says. “There’s nothing more rewarding than seeing success in others and feeling that you were part of that success somehow.”
The ultimate goal of this research is to move toward non-invasive therapeutic targets. By identifying the specific cellular physiology of the thalamus, the lab hopes to refine treatments like deep brain stimulation or even ultrasound stimulation. “We’re working on understanding what parameters are optimal to treat patients,” Viena says. “That way, we can use a method that is less invasive.”
Through this innovative mapping of the midline thalamus, the Viena Lab is not just studying the brain; it is finding the blueprints for restoring the neural networks that sustain human memory and cognitive health.
Jargon Buster
- Optogenetics: A technology that adds light-sensitive “switches” to specific brain cells, allowing researchers to turn them on or off with precise flashes of light.
- Electrophysiology: Recording the electrical firing patterns of neurons.
- Theta & Delta States: Brain wave patterns; Theta occurs during memory tasks and REM sleep, while Delta occurs during deep, restorative sleep.
