An AC constant-response method for electrophysiological measurements of spectral sensitivity functions.
A number of methods have been used in the past to measure spectral sensitivity (S(lambda)) functions of electric responses in the visual system. We present here a microcomputer based, AC, constant-response method for automatic on-line measurement of S(lambda) in cells with or without a sustained tonic response. It is based on feedback adjustment of light intensity to obtain constant peak-to-peak amplitudes of response to a flickering stimulus as the spectrum is scanned between 300 and 700 nm in 4 nm steps. It combines the advantages of: (1) on-line presentation of S(lambda) curves; (2) constant light adaptation; (3) sampling of many points; and (4) fast data collection time. The system can be applied to sensitivity or threshold (e.g., S(lambda), dark adaptation, receptive field) measurements of any electrically recorded visual response.
de Souza
J M
JM
Department of Experimental Psychology, University of São Peulo, Brazil. johns@usp.br
DeVoe
R D
RD
Schoeps
C
C
Ventura
D F
DF
D000818:Animals; D001516:Bees; D010786:Photoreceptor Cells / Q000502:physiology*; D012680:Sensitivity and Specificity; D014793:Visual Cortex / Q000502:physiology*