Rsl. Young et J. Kennish, TRANSIENT AND SUSTAINED COMPONENTS OF THE PUPIL RESPONSE EVOKED BY ACHROMATIC SPATIAL PATTERNS, Vision research, 33(16), 1993, pp. 2239-2252
The present study provides new clues about visual processes underlying
the human pupillary responses evoked by achromatic spatial patterns.
The pupillary responses can be modeled as a combination of two process
es, a temporally transient process which saturates with increasing con
trast and a temporally sustained process which varies linearly with in
creasing grating contrast. The transient process has low-pass, whereas
the sustained process has a middle band-pass spatial filter character
istic. The results support the hypothesis that the visual input to the
pupillomotor nuclei is composed of phasic and tonic visual neurons th
at are functionally similar to those in the magno (M)- and parvo (P)-
cellular layers in the lateral geniculate nucleus.