Spatial navigation is the mental process that allows us to determine our position and figure out how to get to another location. This ability involves creating an internal representation of the world, or a mental map, which we use to plan and execute movements through both familiar and new surroundings.
The Brain’s Internal GPS
At the heart of the brain’s navigational system is the hippocampus, a structure located deep in the temporal lobe. The hippocampus is central to forming and using the mental maps we rely on to navigate, earning it the comparison to a biological GPS. It processes where we are, where we’ve been, and where we’re going by integrating various streams of information.
Within the hippocampus and its neighboring entorhinal cortex are specialized neurons that create our sense of place and direction. These cells form a complex network that underpins our ability to build and read our internal maps. The discovery of these cells changed our understanding of how the brain computes complex cognitive functions.
One type of neuron is the place cell, which becomes active when we are in a specific location within an environment, acting like “you are here” pins on a map. Different place cells fire for different locations, and their combined activity creates a neural representation of an area. This system allows the brain to contain multiple maps for various environments.
Working with place cells are grid cells, located in the medial entorhinal cortex. These cells fire at multiple locations, forming a hexagonal grid pattern that covers the entire environment. This grid provides a coordinate system, allowing the brain to measure distances and add a metric scale to the spatial maps in the hippocampus.
A third type of specialized neuron, the head-direction cell, functions like an internal compass. These cells fire when the head is pointing in a specific direction, regardless of location. Together, place cells, grid cells, and head-direction cells form a circuit that allows the brain to construct a detailed and dynamic representation of our surroundings.
Common Navigational Strategies
People rely on two primary cognitive strategies to find their way: allocentric and egocentric navigation. Allocentric navigation involves creating an objective, bird’s-eye-view map of an environment. This strategy is based on the relationships between external landmarks, independent of one’s own position, and allows a person to plan novel routes and shortcuts.
In contrast, egocentric navigation is self-referenced, defining locations and directions relative to one’s own body. This approach uses cues like “turn left at the next corner” or “walk forward for 100 steps.” It is less about a comprehensive map and more about a sequence of actions from a specific viewpoint.
Most people use a combination of both strategies, switching between them as needed. Integrating these two frames of reference provides a robust representation of the environment. For instance, a person might use an allocentric map to understand a city’s layout while relying on egocentric cues to navigate a specific street.
A related process that supports navigation is path integration, also known as dead reckoning. This is the ability to keep track of one’s position by integrating information about self-motion, such as speed and direction, from a known starting point. Path integration is often used when visual cues are limited or absent.
Factors That Influence Navigational Skills
Navigational ability varies among individuals due to factors like age and experience. Experience and practice shape how well we navigate, as regularly exploring new environments challenges our internal mapping systems, which can maintain or improve their function. A “good sense of direction” often reflects an individual’s preferred strategies and the efficiency of their brain’s navigational circuits.
Skills develop throughout childhood and can decline with healthy aging. Age-related declines are not uniform across all abilities. While the ability to acquire new spatial knowledge may decrease, other skills like path integration can be more resilient into middle age. Older adults may also rely more on familiar routes instead of creating flexible cognitive maps of new spaces.
When Navigation Fails
Difficulties with spatial navigation can be an early symptom of neurodegenerative diseases. Spatial disorientation, such as getting lost in familiar places, is a known sign of Alzheimer’s disease. Over 60% of individuals with Alzheimer’s experience spatial memory deficits and wandering behaviors, which often lead to a diagnosis.
This failure is linked to biological changes in the brain. The hippocampus and the entorhinal cortex, the core of the brain’s internal GPS, are among the first areas damaged by the accumulation of proteins associated with the disease. This damage disrupts the function of the specialized neurons responsible for creating and reading cognitive maps.
The breakdown of the brain’s navigation system in Alzheimer’s appears to follow a pattern. Evidence suggests that allocentric mapping ability, which relies on grid cells, is affected early on, forcing individuals to rely more on egocentric, route-based strategies. As the disease advances and damage spreads, these remaining navigational mechanisms also become impaired, leading to profound disorientation.
The Effect of Modern Technology on Navigation
The widespread availability of GPS has raised questions about its impact on our innate navigational abilities. A growing body of research suggests that over-reliance on these devices may affect the brain’s spatial memory systems. When we outsource navigation to a device, we reduce the cognitive load on our hippocampus and related brain regions.
This “use it or lose it” concept is supported by studies showing that individuals who frequently use GPS tend to perform worse on spatial memory tasks without assistance. Habitual GPS use may diminish our capacity to build detailed internal representations of our surroundings because it encourages a passive, egocentric form of navigation. We simply follow instructions without engaging the allocentric, map-building functions of the hippocampus.
This lack of engagement may lead to reduced activity and even structural changes in the hippocampus over time. One study observed that greater GPS use over a three-year period was associated with a steeper decline in hippocampus-dependent spatial memory. While using GPS will not cause a neurodegenerative disease, it may affect cognitive resilience, making individuals more susceptible to showing symptoms of memory loss sooner if they develop a condition like Alzheimer’s.