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Dark‐adaptation mechanisms of the long‐wave foveal cones
Author(s) -
STABELL ULF,
STABELL BJØRN
Publication year - 1989
Publication title -
scandinavian journal of psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.743
H-Index - 72
eISSN - 1467-9450
pISSN - 0036-5564
DOI - 10.1111/j.1467-9450.1989.tb01083.x
Subject(s) - foveal , adaptation (eye) , photopigment , logarithm , cone (formal languages) , optics , chemistry , physics , mathematics , retina , mathematical analysis , retinal , biochemistry , algorithm
The ordinary long‐term rod and cone dark‐adaptation curves have generally been assumed to follow a single exponential rate of recovery. However, in two previous papers on rod dark‐adaptation (Stabell et al. , 1986 a, b ), the recovery curve was found to consist of three different sections. The results of the present paper show the same type of recovery function with three different sections for the long‐term dark‐adaptation curve of the long‐wave cone system. During the major, middle section log cone threshold, like log rod threshold, is linearly related to the logarithm of the concentration of bleached photopigment. Presupposing that the bleached cone photopigment acts as a ligand, the change in threshold level obtained during the middle section of the dark‐adaptation curve is well described by the change in activity rate of an allosteric, positively cooperative enzyme built as a dimer.