EFFECTS OF INTENSITY AND WAVE LENGTH ON DRIVING CORTICAL ACTIVITY IN MONKEYS

Abstract

A further investigation of the modification of cortical activity by means of intermittent photic stimulation has been made on 8 adult monkeys (Macaca mulatto) with reference to the relative effectiveness of intensity and wave length. A range of intensities for white or neutral light of approx. 2 log units was explored. For a given interval of time, flashes of neutral light at 80 footcandles were about twice as effective in producing driving as flashes at 4 footcandles. In determining the relative effectiveness of wave length, neutral and Wratten monochromatic filters Nos. 70, 71, 72, 73, 74, and 75 were employed. When equated for luminous energy (at 4 footcandles) relatively monochromatic light was approx. 1.6 times as effective, on the avg., in producing driving as neutral light. The blue region of the spectrum was 1.8 times as effective, on the avg., in producing driving as the red region.