Visual and Auditory Cues Support Place Field Activity of Hippocampal Units in the Rat
The firing rates of hippocampal units vary as a function of the animal’s position in space. For example, on an elevated radial maze a particular cell might show enhanced activity on one arm. In intact rats, if the maze is rotated within the environment, the place field of the cell persists with respect to the environment and not to the maze. Lesions of the fornix or entorhinal cortex reduce the robustness of place field activity and severely disrupt persistence with respect to the environment.
In blind and deaf rats hippocampal cells have place fields. Following maze rotation the place fields of most cells (11 of 15) remain on the original arm of the maze. In the other (4) cells the place fields persist with respect to the environment, but spinning the rat, to disturb vestibular function, disrupts this environmental persistence. Thus removal of sensory information has similar effects on hippocampal place cell activity as does lesions of hippocampal connections.
KeywordsFiring Rate Entorhinal Cortex Place Field Persistent Cell Hippocampal Pyramidal Cell
Unable to display preview. Download preview PDF.
- Best, P. J., and Ranck, J. B., Jr., Reliability of the relationship between hippocampal unit activity and sensory-behavioral events in the rat, Exp. Neurol. in press.Google Scholar
- Hill, A. J., 1979, Unpublished doctoral dissertation.Google Scholar
- O’Keefe, J., and Nadel, L., 1978, “The Hippocampus as a Cognitive Map,” Claranden Press, Oxford.Google Scholar
- O’Keefe, J., Nadel, L., Keightly, S., and Kell, D., 1975, Fornix lesions selectively abolish place learning in the rat, Ex1. Neurol., 48: 152.Google Scholar
- Pavlov, J., 1927, “Conditioned Reflexes,” Oxford University Press,London.Google Scholar
- Rescorla, R. A., and Wagner, A. R., 1972, A theory of Pavlovian conditioning: variations in the effectiveness of reinforcement and nonreinforcement, in: “Classical Conditioning II: Current Research and Theory,” A. H. Black and W. F. Prokasy, eds., Appleton-Century-Crofts, New York.Google Scholar
- Tolman, E. C., 1932, “Purposive Behavior in Animals and Men,” Century, New York.Google Scholar
- Vernier, V. G., and Alleva, F. R., 1968, The bioassay of kanamycin auditory toxicity, Archives Internationales de Pharmacodynamie, 176: 59.Google Scholar