Experimental Investigations with Electrical Stimulation of the Oculomotor Nucleus: The Effects of Stimulus Frequency

摘要

Procedures and methods for the study of the central control of accommodation by electrical stimulation are presented. Positive accommodation, an increase in the dioptric power of the eye, and negative accommodation, a decrease in the dioptric power of the eye, were found by brain-stem stimulation in the cat. The frequency threshold for positive accommodation was about 4 cps. The frequency threshold for negative accommodation was about 10 cps. Frequencies of 60 and 90 cps were more efficient in producing positive accommodation, while negative accommodation varied directly with the frequency up to the 120 cps limiting frequency. The central control of accommodation by the oculomotor nucleus appears to depend somewhat on the stimulus frequency. Not all responses can be explained by frequency alone, and a definitive theory must await further data and analysis. (Author)