Hippocampal Activity and Behavior
The problem I hoped to solve in 1964–65 was to determine the conditions under which rhythmical slow waves appeared in the hippocampus of the rat. The method adopted was to place rats with chronically implanted electrodes inside a box with a wood frame covered with a grounded copper screen (Faraday cage) to reduce extraneous electrical signals such as the ubiquitous 60 Hz line interference. One electrode, implanted in the skull, connected the rat to ground; others permitted the recording of slow electrical potentials from the hippocampus and the neocortex on an ink-writing oscillograph or polygraph via a light flexible set of leads made from phonograph pick-up wire. I sat close to the rat with a keyboard on my lap to allow me, by closing appropriate switches, to record on the polygraph record what the rat did.
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Notes on Chapter 2
- 2.Harper, R. (1968.) Behavioral and electrophysiological studies of sleep and animal hypnosis. Unpublished Ph.D. thesis, McMaster University, Hamilton, Ontario. Harper, R. M. (1971) Frequency changes in hippocampal electrical activity during movement and tonic immobility. Physiology and Behavior, 7: 55–58.Google Scholar
- 3.Vanderwolf, C. H. (1967). Behavioral correlates of “theta” waves. Proceedings of the Canadian Federation of Biological Societies, 10: 4142.Google Scholar
- 5.Brian Bland and I (we were both present) each remember this story in this way but according to Ian, a woman stood up after his talk and said: “You mean to tell me that these waves always accompany swimming, running in a treadmill, lever pressing, and jumping out of boxes? I don’t believe you! ”. Perhaps both of these stories are true, possibly referring to events occurring at different meetings. We all gave a lot of talks at meetings in those days and, after 30 years, one’s recollections become a bit hazy. The specific words attributed to various people in this book are, at best, only approximations.Google Scholar
- 6.Dalton, A. (1968). Hippocampal electrical activity in operant conditioning. Unpublished Ph.D. thesis, McMaster University, Hamilton, Ontario.Google Scholar
- Black, A. H. (1975) Hippocampal electrical activity and behavior. In R.L. Isaacson and K.H. Pribram (eds) The hippocampus, volume 2: Neurophysiology and behavior,New York: Plenum Press, 129–167.Google Scholar
- 8.The rhythmical slow activity of the hippocampus is often referred to informally as the “theta rhythm” or the “hippocampal theta rhythm”. I had at first adopted these terms but gave them up when a journal editor insisted that the term “theta rhythm” was already in use to refer to a 4–7 Hz waveform occurring in human electroencephalography. Since the rat hippocampal rhythm can rise to a frequency of about 12 Hz, new terminology was required. I chose rhythmical slow activity (RSA).Google Scholar