Effects of total light flux on critical flicker frequency after frontal lobe lesion.

Abstract

This study is concerned with the effect of frontal lobe lesions in man upon the fusion threshold for flickering light (CFF) and the effect on CFF of varying both target area and light intensity (hence total light flux). The exptl. group consisted of patients with frontal lobe lesions. The control group was composed of normal subjects selected from hospital personnel. The CFF increases linearly with increase in log target area. The more the light energy is concentrated on the fovea, the higher the fusion threshold. Frontal lobe lesions, incurred 4-6 yrs. before testing, do not significantly depress CFF, regardless of target size or light intensity. Transient depressions in CFF may occur after frontal lobe lesions, but injuries to the retro-chiasmal pathways appeared to be necessary to produce a lasting reduction of CFF in man.