抄録
We studied on the longer-term changes of eye movements during compensation in goldfish, to provide a time course for future investigations correlating space adaptation mechanisms. Vertical and torsional eye movements evoked by body tilt were video recorded and analyzed frame-by-frame using personal computer. In normal fish, largest vertical eye movements were evoked by left- or right-ward body tilt and the largest torsional eye movements were evoked by head up or head down body tilt. After removal of left otolith, spontaneous nystagmus was not observed in the goldfish following recovery from the surgery. However, unilateral removal of the otolith resulted in an acute decrease in response amplitude of both vertical and torsional eye movements to body tilt. Especially, vertical eye movement evoked by left ward body tilt showed significant decrease compared to normal fish. Both vertical and torsional eye movements showed abrupt recovery within 1 day. Recovery process of torsional eye movement was separated to two stages, that is early first recovery and later slow recovery. During recovery process, the properties of vertical and torsional eye movements for tilting stimulation were preserved. Even after 6 month, response amplitude of eye movement had never recovered to its normal value. The results suggest that the goldfish is not capable of completely recovering of eye movements evoked by body tilt following 6 month of compensation for unilateral removal of otolith. [Jpn J Physiol 55 Suppl:S229 (2005)]
