To find out more about the podcast go to How Animals Build a Sense of Direction.
Below is a short summary and detailed review of this podcast written by FutureFactual:
How Animals Build a Sense of Direction: Head Direction Cells, Place Cells, and Island Navigation
Quanta Magazine explains how animals navigate by building internal neural maps using place cells, grid cells, and head direction cells. The episode highlights a field study with Egyptian fruit bats on Latham Island, showing how landmarks anchor orientation in a space, bridging laboratory discoveries with real-world navigation.
Introduction: A Sense of Direction as Part of Navigation
Navigation is not just about knowing where you are; it requires knowing which way you are heading. In this podcast, Yasmin Salioglu describes how animals build directional sense on top of a map of places, using place cells that fire at specific locations, grid cells that provide a coordinate system, and head direction cells that act like a compass. The big idea is that direction is a critical component of spatial behavior, and it must be anchored to the environment for successful navigation. The host and guest discuss how this navigation toolkit has been studied largely in the lab, but how real-world navigation in complex environments may depend on the same neural machinery.
"Sense of direction is a part of navigation, We both need to know where we're at in our environment, but we also need to know which direction we're going." - Yasmin Salioglu, biology staff writer
From Place Cells to Grid Cells and Head Direction Cells
The conversation sketches the historical arc of spatial neuroscience. John O'Keefe’s discovery of place cells in the 1970s revealed neurons that fire when an animal is in a particular location. A few decades later, May-Britt Moser and Edvard Moser identified grid cells that fire in a hexagonal grid, providing a coordinate framework for the brain to map space. Together, place cells and grid cells form a scaffold for spatial understanding, but knowing where you are is not enough to get you somewhere; you must also know which direction you are facing. This leads to the head direction cell system, a ring-like network that fires depending on the animal’s head orientation, effectively functioning as a compass that is anchored to the environment rather than a magnetic sensor. A case is made for a “global compass” or a mosaic arrangement, with research suggesting landmarks can anchor the head direction cells to specific directions.
"Head direction cells fire based on the direction that the animal's head is facing. It's sort of like a compass." - Yasmin Salioglu, biology staff writer
The Wild Island Bat Experiment: Bridging Lab to Field
To move neuroscience beyond controlled cages, the researchers led by Nachem Ulanovsky implanted microwires into Egyptian fruit bats and sent them to Latham Island, an uninhabited natural setting. The bats’ neural activity and location were recorded as they flew around, allowing scientists to observe head direction cell activity in a real landscape. Initially, the cells fired more crudely, but over days they anchored to specific directions as the bats learned the island’s geography. This setup offered a test between the global compass hypothesis and the mosaic hypothesis. The island’s coastline and landmarks—rather than celestial cues like stars or the moon—appeared to anchor the head direction cells, creating a continuous directional map that linked brain activity to movement on the ground. The environment remained a contained island, so questions remain about how these findings scale to larger or entirely different spaces, but the data strongly support landmarks guiding directional orientation in a natural setting.
"the landmarks formed a continuous map of the island." - Yasmin Salioglu, biology staff writer
Implications for Humans and Open Questions
While humans have place cells and grid cells, the existence of head direction cells in humans has not been definitively proven, though it is a reasonable expectation given our navigational abilities. The study on bats helps illuminate how the brain might integrate stable landmarks when navigating unfamiliar environments, suggesting that our internal maps rely on environment-bound cues to keep direction accurate even as we move and reorient. The discussion also touches on individual differences in sense of direction and how modern tools like smartphones influence our internal mapping. A key question remains: how do internal maps adapt when landmarks change, and how do we reconcile internally generated maps with external cues in complex, dynamic cities? The host and guest emphasize that much remains to be learned about how this direction-detecting system operates in humans and across species, and about how flexible the system is in real-world settings.
"we still need to prove this exists in humans." - Yasmin Salioglu, biology staff writer
