title: Role of extrinsic noise in the sensitivity of the rod pathway: rapid dark adaptation of nocturnal vision in humans.
abstract: Rod-mediated 500 nm test spots were flashed in Maxwellian view at 5 deg eccentricity, both on steady 10.4 deg fields of intensities (I) from 0.00001 to 1.0 scotopic troland (sc td) and from 0.2 s to 1 s after extinguishing the field. On dim fields, thresholds of tiny (5') tests were proportional to √I (Rose-DeVries law), while thresholds after extinction fell within 0.6 s to the fully dark-adapted absolute threshold. Thresholds of large (1.3 deg) tests were proportional to I (Weber law) and extinction thresholds, to √I.
  
  
  CONCLUSIONS
  rod thresholds are elevated by photon-driven noise from dim fields that disappears at field extinction; large spot thresholds are additionally elevated by neural light adaptation proportional to √I. At night, recovery from dimly lit fields is fast, not slow.
authors.forename: Adam
authors.initials: A
authors.lastname: Reeves
authors.forename: Rebecca
authors.initials: R
authors.lastname: Grayhem
mesh_terms: D000328:Adult; D003623:Dark Adaptation / Q000502:physiology* / Q000528:radiation effects*; D005108:Extinction, Psychological / Q000528:radiation effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055254:Night Vision / Q000502:physiology* / Q000528:radiation effects*; D010775:Photic Stimulation; D017948:Retinal Rod Photoreceptor Cells / Q000528:radiation effects*; D012684:Sensory Thresholds / Q000528:radiation effects; D055815:Young Adult