The Hippocampal Role In Spatial Memory

Spatial memory is memory that utilizes different neurons to help remember the location of one’s environment (Bear 2016). The hippocampus is thought to be responsible for spatial memory. Evidence in the hippocampal role in spatial memory has come from the Morris water maze test. The Morris water maze begins by putting a rat in a circular pool of cloudy water. Submerged in the pool, is a podium that will get the rat out of the water. First time rats will swim for longer periods of time and take a longer path to get to the podium. All subsequent trials for normal rats, the rat will go straight to the podium. However, if the rat has damage to the bilateral hippocampus, the rat cannot remember the location of the podium or fail to find it
Place cells help spatial memory by remembering locations in the environment by perceiving the important parameters. Place cells are especially sensitive to geometric boundaries (Moser 2008). Other evidence for the hippocampal role in spatial memory stems from the recording of electrical spikes of neurons from different parts of the rats environment (Burgess 2011). If a rat is placed in a box and neuronal activity is recorded, each neuron will fire consistently with a particular place in the box. If the rat moves to a new location a different neuron will start firing. Collectively, the neurons represent the entire environment surveyed. Grid cells are also important in determining one’s location and orientation in the environment. Grid cells are located in the human entorhinal cortex. The entorhinal cortex communicates with the hippocampus. Grid cells help to determine a path to the desired location by creating periodically firing, triangular “grids” as the environment is explored. It has been determined that both grid and place cells do not mirror the environment completely (Moser 2008). It a spatial landmark is removed, but the environment stays similar, both grid and place cells will still fire.