Objects boost our inner compass

In our daily lives, we use objects as spatial landmarks – such as a particular clock tower when walking through the city – to find the right direction. This works because our brain devotes considerable computing power to breaking the world down into objects. In addition, our current position in the world is constantly processed by specialized neurons in the brain's spatial navigation system called the place, grid and head direction cells. The activity of the head direction cells is tuned to a narrow range of head directions. This means that when the head is turned in a certain direction, only the cells responsible for that head direction are active, while the others are inhibited. However, it is not yet sufficiently clear how looking at specific objects influences these neurons to help us orient better.

Researchers led by Prof. Dr. Emilie Macé, head of the “Brain-wide networks” research group in the Department of Ophthalmology at the University Medical Center Göttingen (UMG), co-spokesperson of the Else Kröner Fresenius Center for Optogenetic Therapies at the UMG and member of the Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), have revealed – together with Canadian cooperation partners – that a brain region important for our inner compass, the postsubiculum, was activated when mice look at objects. In addition, it was observed that when looking at an object, the head direction cells tuned to that direction were more active than without the object. On the other hand, the head direction cells tuned to other directions were also more inhibited. As a consequence, the direction of the object becomes more accurately represented by the head direction cells.

"We’ve all experienced how landmarks like buildings make us feel more confident about where we are. But how the brain uses such visual cues to improve our sense of direction is still unclear. In our study, we found one piece of this puzzle: we identified a brain region where neurons respond both to head direction and to the presence of objects. When an object is seen, the neurons encoding head direction become more precise—essentially sharpening our internal compass. This shows that objects help us navigate better by enhancing the brain’s directional signals," says Prof. Macé, last author of the study. 

The results of the study have been published in the journal “Science”.

Original publication:
Dominique Siegenthaler, Henry Denny, Sofía Skromne Carrasco, Johanna Luise Mayer, Daniel Levenstein, Adrien Peyrache, Stuart Trenholm and Emilie Macé. Visual objects refine head direction coding. Science (2025). DOI: 10.1126/science.adu9828

The study in detail
To find out which parts of the brain react to objects such as items or buildings, the researchers analyzed the brain activity in a mice model. While the animals were shown 48 images with and without objects, they were examined using functional ultrasound imaging. This method measures the increase in blood volume when a part of the brain becomes more active. In this way, the researchers were able to identify brain regions that responded preferentially to objects. 

"Unexpectedly, the method showed that the postsubiculum, a brain region that contains many head direction cells, had the strongest object preference, and we wondered how visual signals influence the activity of the head direction cells,“ says Dr. Dominique Siegenthaler, postdoctoral researcher in Prof. Macé's ”Brain-wide networks" working group and first author of the study.

To further investigate the activation of head alignment cells, another experiment was conducted. Mice were allowed to move freely in a white box with a single object image attached to the wall. The electrical signals of postsubiculum neurons were recorded together with the position and head direction of the mouse in the box. This showed that neurons tuned to a specific direction reacted more strongly when the mouse could see the object when looking in that direction. A computer model confirmed the experimental observations.

Partner institutions involved in the study
Max Planck Institute for Biological Intelligence in Planegg, Germany, the Montreal Neurological Institute of the McGill University as well as the Mila - Quebec AI Institute, both in Montreal, Canada.

Scientific expert: 
Prof. Dr. Emilie Macé, Department of Ophthalmology, Phone +49 551 / 39-61117, emilie.mace(at)med.uni-goettingen.de

Press contact:
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