Brain Navigation System Insights Aid Dementia Understanding

Scientists have identified a 'dial' in the human brain that ramps up when we explore a new area, potentially aiding our understanding of why getting lost is often an early symptom of dementia, such as Alzheimer's disease.

The findings were published on December 4 in the journal Nature Communications. Researchers, led by Deniz Vatansever at Fudan University in China, ran brain scans using functional MRI and virtual reality to observe brain activity in 56 healthy volunteers aged 20 to 37 as they navigated a virtual environment.

The study specifically focused on the hippocampus, a region crucial for memory and navigation, where they identified a gradient of activity from familiar to unfamiliar locations. Cells in the head of the hippocampus activated in response to familiar areas, while those at the tail responded to new locations.

This organization could explain discrepancies in previous research regarding brain responses to novelty and familiarity. Additionally, other brain areas also exhibited different activation patterns for familiar and unfamiliar locations.

Notably, familiar areas activated networks linked to motor control and memory, while novel areas engaged networks associated with focus and perception. These findings suggest that the brain adapts to new environments by absorbing relevant details and combining memory and motor control for navigation in familiar settings.

Vatansever indicated that these insights might explain early signs of dementia, as the hippocampus is among the first brain regions affected by Alzheimer's disease. Louis Renoult, a cognitive neuroscientist at the University of East Anglia, emphasized the connection between navigation and episodic memory, which is particularly vulnerable in the early stages of Alzheimer's.

Understanding how navigation is encoded in the brain could reveal early measurable signs of dementia, reinforcing the notion that enhancing spatial novelty and memory is essential for maintaining independence in individuals experiencing cognitive decline.