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Dark‐adaptation of the human rod system: A new hypothesis
Author(s) -
STABELL ULF,
STABELL BJØRN,
NORDBY KNUT
Publication year - 1986
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.1467-9450.1986.tb01195.x
Subject(s) - rhodopsin , adaptation (eye) , constant (computer programming) , chemistry , exponential function , contrast (vision) , optics , psychology , statistics , mathematics , retinal , physics , mathematical analysis , biochemistry , computer science , programming language
Following a long, full bleach, rod dark‐adaptation curves from two normal trichromats were obtained with test fields of various size, exposure time and retinal eccentricity. The results show that there is a substantial region of threshold recovery with an approximately constant, linear slope of about 0.27 log per minute of dark‐adaptation, which is independent of the test variables. It is suggested that the increase in sensitivity during this constant, linear slope is completely determined by changes in the concentration of bleached rhodopsin. The relationship between change of relative threshold (T) and fraction of bleached rhodopsin ( B ) is given by T=B 3,7 . This exponential law is well described by the displacement of the equilibrium between the active and inactive states of an allosteric enzyme built as a tetrarner.