Neural 'Pedometer' in Rats and Humans Tracks Distance Estimation

Recent research from the University of St Andrews has uncovered fascinating insights into how both rats and humans gauge the distance traveled. Humans naturally rely on various cues such as familiar landmarks and a sense of direction, but crucially, we also estimate how far we've walked. In a groundbreaking study published in Current Biology, scientists trained rats to run specific distances to receive rewards while recording activity from individual cells in their navigation system, notably the entorhinal cortex.

Previous studies identified that some neurons in this area exhibit rhythmic activity peaks approximately every 30 centimeters, functioning like a neural 'pedometer.' When researchers altered the environmental setup to disrupt this regular activity pattern, both the rats' distance estimation accuracy and the regularity of these neural signals declined. This correlation suggests that the rhythmic activity in these neurons is vital for accurate distance tracking.

To assess if humans employ a similar mechanism, the team recreated the task in a controlled environment—a 12.5-meter-long corridor inside the St Andrews Students' Union. Human participants demonstrated precise distance judgment skills, and, akin to the rats, their accuracy diminished when environmental cues were manipulated to distort the neural 'pedometer' signals.

The researchers pinpointed the activity in the entorhinal cortex as the neural basis for this distance estimation. This brain region is among the first to deteriorate in Alzheimer’s disease, suggesting that impairments in this neural pedometer could serve as early indicators of the disease.

Professor James Ainge, the lead author, expressed enthusiasm about the findings: "Linking the ability to estimate distance with this regular pattern of activity in the entorhinal cortex underscores the shared mechanisms across species. The consistent errors observed in different environments further confirm the universality of this neural system."

These discoveries not only deepen our understanding of spatial navigation but also open new avenues for early diagnosis of neurodegenerative conditions based on the integrity of this neural 'pedometer.'

Source: https://medicalxpress.com/news/2025-09-rats-humans-neural-pedometer-distance.html