Spatial Memory
What is Spatial Memory?
Spatial memory refers to memories for locations of events and the events occurring at these locations. Spatial memory, therefore, encodes information about location, orientation, distance and direction.
Every time we remember where we left our keys, find our way by locating a prominent building, successfully return home from the grocery store, and remember where our car is parked after coming out a different door, we are using spatial memory.
Spatial memory consists in the formation of environment-specific place maps. The information orients a subject in space and thus is critical for the contextualization of memories and actions that rely on it (Mose and Moser, 2008; Hasselmo, 2009).
Spatial memory has numerous functions critical in our everyday life.
- It enables us to remember places and to remember how to find our way around.
- We can recognize places as familiar and recall routes from one location to another.
- We can devise novel routes or short cuts for reaching a goal.
Spatial memory is also used for locating objects, and for remembering how to find things, which may range from landmarks along routes such as a service station on the motorway, to objects lying around the house such as a pair of spectacles.
Memory for scenes and for the layout of objects within scenes mediates our interaction with the immediate environment. All these functions involve knowledge of the spatial layout of the environment.
Brain Areas Involved in Spatial Memory
Hippocampal place cells and entorhinal grid cells enable spatial memory in the brain’s navigational system (O’Keefe and Nadel, 1978). Grid cells are a more fundamental feature of this system and drive place cells.
They form an internal positioning system, informing the organism of its location independently of external cues.
Place cells use this information along with environmental cues to create a sense of space. They are sensitive to both internal sensory information in the brain and external sensory information from the environment with which the organism interacts.
The locus coeruleus in the brainstem has a critical role in this process. By sending inputes to the hippocampus, it enables the formation of neural representations of new places (Wagatsuma, Okuyama, Sun et al., 2008).
The visual cortex is critical for the visual aspect of spatial memory, or visual-spatial memory, which depends on inputs from this part of the occipital lobe to the hippocampal-entorhinal circuit.
Hippocampal networks that allow fast storage and retreiveal of information about place may be at the core of declarative memory formation.
Together with one’s orientation to time, spatial memory provides one with the gist rather than details of the milieu in which one acts. One’s orientation to space may be unconscious or conscious, depending on whether the cognitive demands of the milieu are habitual or novel.
