J. Bilotta et al., THE CONTRIBUTIONS OF ON-PATHWAYS AND OFF-PATHWAYS TO CONTRAST SENSITIVITY AND SPATIAL-RESOLUTION IN GOLDFISH, Vision research, 35(1), 1994, pp. 103-108
DL-2-amino-4-phosphonobutyric acid (APB) reduces the sensitivity of ON
- and OFF-responses in goldfish retina, although the ON-responses are
reduced significantly more than the OFF-responses. This paper describe
s the effects of APB on behavioral sensitivity of goldfish to spatial
sinusoidal gratings. Fish were classically conditioned to suppress res
piration upon presentation of gratings drifting at 1 Hz; contrast thre
sholds were measured by an observer-based two-alternative forced-choic
e procedure. Thresholds were repeated following intraocular injections
of APB or physiological saline. Saline had no effect, but APB dramati
cally reduced contrast sensitivity and shifted contrast sensitivity fu
nctions to lower spatial frequencies. The results suggest that both ON
- and OFF-pathways are necessary for normal spatial vision and that th
e effects of APB are consistent with the disruption of both ON- and OF
F-pathways.