Place Cells: What are they?

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Yesterday in class the topic of place cells came up during Blake and Fran’s presentation on the Limbic System. This prompted me to look into place cells a bit more because they were extremely interesting. In class we discussed that place cells can be found in the hippocampus and have a role in spatial memory. Essentially, using place cells, our brains encode information about the areas that we are in so that when we return to these areas, those same neurons fire and the feeling of familiarity arises.  Place cells allow us to be familiar with pathways that we have taken before. One neuron does not fire for one location, instead it’s the pattern of activity in the brain that causes this familiar sensation. I thought the above picture was a perfect example of what place cells are / how they work. Place cells fire when we enter a location that we are familiar with and if we enter if from a different position than normal our place cells reorient to the new position. But this firing can be interrupted if items in the room have been shifted around, causing initial disorientation.

We brought up some interesting topics about place cells in class. We discussed if place cells could encode for emotional memories, had some link to episodic and not just spatial memory, and if the misfiring of place cells could/did have an effect in things like deja vu and jamais vu (the feeling of unfamiliarity in a place that is familiar).  After doing some research I found that place cells do have a role in at least the encoding of fearful stimuli. It was found that place cells modified their firing when a rodent was in the presence of an aversive stimulus, a form of emotional learning. This modification is remembered by the brain, providing it with a memory of any negative stimulus that is associated with a certain location (Wang et al, 2012). The modification of the place cells firing linked whatever emotional experience to that modification and to that location. It has also been found that place cells may play a role in goal-directed, navigational behavior (Pfieffer & Foster, 2013). So not only are place cells involved in the familiarity of a location, but they also may be involved in the planning out of getting to that certain location. Another possibility/role of place cells could be the correlation with remembering something important. If in a certain room when something important is thought of, will returning to that specific room trigger the memory of what was though of? It is an interesting idea that I could not find any research on through my searches but would be very interested in learning more about.

References: Carlson, N.R. (2011). Foundations of behavioral neuroscience. Boston, MA: Allyn & Bacon.

Pfeiffer, B. E., & Foster, D. J. (2013). Hippocampal place-cell sequences depict future paths to remembered goals. Nature497(7447), 74-79.

Wang M, Wann E, Yuan R, Álvarez M, Stead S, Muzzio I. Long-term stabilization of place cell remapping produced by a fearful experience. The Journal Of Neuroscience, 32(45), November 2012;32(45):15802-15814.

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