Colour and flicker thresholds for high frequency increments.

Previous investigators have elicited spectral sensitivity functions for the chromatic and achromatic systems by manipulating the stimulus spatiotemporal parameters. An alternative strategy for obtaining these two functions is to use a single set of stimulus parameters and vary the threshold criterion. This can be accomplished by determining colour and flicker thresholds for a high frequency train of increments. In the current study, spectral sensitivity functions, based on colour and flicker thresholds, were determined for increments presented at 25 Hz. The colour and flicker threshold functions are similar in form to those previously published for the chromatic and achromatic systems. The existence of distinct threshold functions for colour and flicker are interpreted in the context of parvo and magno pathways. Potential clinical applications of this model are discussed.