A study pinpointed human neural compass

Scientists at the University of Birmingham and Ludwig Maximilian University of Munich have identified a pattern of brain activity that helps prevent us from getting lost. They have pinpointed the location of an internal neural compass, which the human brain uses to orient itself in space and navigate the environment.

The findings reveal precisely calibrated head-direction cues in the brain. They are significant for understanding disorders like Parkinson's and Alzheimer's, where navigation and direction are frequently affected. They are comparable to neural codes seen in rodents.

First author Dr Benjamin J. Griffiths said: "Keeping track of the direction you are heading in is pretty important. Even small errors in estimating where you are and which direction you are heading in can be disastrous. We know that animals such as birds, rats, and bats have neural circuitry that keeps them on track, but we know surprisingly little about how the human brain manages this out and about in the real world."

52 healthy individuals were recruited to participate in a series of motion-tracking tests, during which a scalp EEG was used to capture their brain activity. This allowed scientists to track the individuals' brain activity as they shifted their heads in response to cues displayed on various computer screens.

In a different investigation, the scientists saw signals from ten subjects already receiving intracranial electrode monitoring for diseases, including epilepsy.

Every task required participants to move their heads or occasionally their eyes, and the brain signals resulting from these movements were captured by intracranial EEG (iEEG), which collects information from the hippocampus and surrounding regions, and EEG caps, which monitor signals from the scalp.

The researchers showed a finely tuned directional signal that could be detected just before physical changes in head direction among participants after they had considered "confounds" in the EEG recordings caused by things like muscle movement or the participant's position within the environment.

Dr Griffiths added: "Isolating these signals enables us to focus on how the brain processes navigational information and how these signals work alongside cues such as visual landmarks. Our approach has opened up new avenues for exploring these features, with implications for research into neurodegenerative diseases and even for improving navigational technologies in robotics and AI."

Scientists plan to apply their learning to investigate how the brain navigates through time to find out if similar neuronal activity is responsible for memory.

Journal Reference:

1. Griffiths, B.J., Schreiner, T., Schaefer, J.K. et al. Electrophysiological signatures of veridical head direction in humans. Nat Hum Behav (2024). DOI: 10.1038/s41562-024-01872-1