Rat hippocampal theta rhythm during sensory mismatch
Version of Record online: 27 OCT 2008
Copyright © 2008 Wiley-Liss, Inc.
Volume 19, Issue 4, pages 350–359, April 2009
How to Cite
Zou, D., Aitake, M., Hori, E., Umeno, K., Fukuda, M., Ono, T. and Nishijo, H. (2009), Rat hippocampal theta rhythm during sensory mismatch. Hippocampus, 19: 350–359. doi: 10.1002/hipo.20524
- Issue online: 26 MAR 2009
- Version of Record online: 27 OCT 2008
- Manuscript Accepted: 12 SEP 2008
- CREST, JST, Japan
- sensory conflict;
- backward translocation;
- passive translocation
It has been suggested that sensory mismatch induces motion sickness, but its neural mechanisms remain unclear. To investigate this issue, theta waves in the hippocampal formation (HF) were studied during sensory mismatch by backward translocation in awake rats. A monopolar electrode was implanted into the dentate gyrus in the HF, from which local field potentials were recorded. The rats were placed on a treadmill affixed to a motion stage translocated along a figure 8-shaped track. The rats were trained to run forward on the treadmill at the same speed as that of forward translocation of the motion stage (a forward condition) before the experimental (recording) sessions. In the experimental sessions, the rats were initially tested in the forward condition, and then tested in a backward (mismatch) condition, in which the motion stage was turned around by 180° before translocation. That is, the rats were moved backward by translocation of the stage although the rats ran forward on the treadmill. The theta (6–9 Hz) power was significantly increased in the backward condition compared with the forward condition. However, the theta power gradually decreased by repeated testing in the backward condition. Furthermore, backward translocation of the stage without locomotion did not increase theta power. These results suggest that the HF might function as a comparator to detect sensory mismatch, and that alteration in HF theta activity might induce motion sickness. © 2008 Wiley-Liss, Inc.