I have 3 questions that are interrelated:
After reading the proper literature on the subject, my understanding of the place field is that it's a place in space to which an animal's place cell reacts by firing. Then there might also be another place in field to which the same place cell reacts by firing. Is this understanding correct?
1.1 Why is it called place "field," what does the "field" actually imply, etymologically speaking?
1.2. The Wikipedia Grid Cell Page says that:
By contrast, if a place cell from the rat hippocampus is examined in the same way (i.e., by placing a dot at the location of the rat's head whenever the cell emits an action potential), then the dots build up to form small clusters, but frequently there is only one cluster (one "place field") in a given environment, and even when multiple clusters are seen, there is no perceptible regularity in their arrangement.
So then what are those "clusters", i.e. I guess the place fields, are they the ones I highlighted in red on this picture (sorry, I am a very visual learner!) and also, why do they fire in clusters?
The Wikipedia Page has the following description of this picture but I am still not sure I am understanding it correctly:
Spatial firing patterns of 8 place cells recorded from the CA1 layer of a rat. The rat ran back and forth along an elevated track, stopping at each end to eat a small food reward. Dots indicate positions where action potentials were recorded, with color indicating which neuron emitted that action potential.
The first question stems from the second and the main one I am confused about: what is actually the difference between the place cells and the grid cells, in a layman terms (beyond the obvious structural differences, i.e. that the place cells are pyramidal neurons and the grid cells fire in a hexagonal pattern)?
In terms of their functional differences, is the difference mainly in the fact that the grid cells are theoretically responsible for path integration, whereas "The place cells are thought, collectively, to act as a cognitive representation of a specific location in space, known as a cognitive map" ( O’Keefe John, 1978 ).
What is the physiological or anatomical difference between.... Available from: https://www.researchgate.net/post/What_is_the_physiological_or_anatomical_difference_between_place_cells_and_grid_cells_in_the_hippocampus [accessed Aug 16, 2017].
O'Keefe, John (1978). The Hippocampus as a Cognitive Map. ISBN 978-0198572060.