Spatial summation properties of the human ocular following response (OFR): evidence for nonlinearities due to local and global inhibitory interactions.

摘要: Abstract Ocular following responses (OFRs) are the initial tracking eye movements that can be elicited at ultra-short latency by sudden motion of a textured pattern. A recent study used stimuli consisting two large coextensive sine-wave gratings with same orientation but different spatial frequency and moving in ¼-wavelength steps or opposite directions: when differed contrast more than about an octave then one higher completely dominated OFR lower lost its influence as though suppressed [Sheliga, B. M., Kodaka, Y., FitzGibbon, E. J., & Miles, F. A. (2006). Human ocular initiated competing image motions: Evidence for winner-take-all mechanism. Vision Research, 46, 2041–2060]. This (WTA) outcome was attributed to nonlinear interactions form mutual inhibition between mechanisms sensing motions. In present study, we recorded horizontal OFRs vertical were each confined strips extended full width our display (45°) only 1–2° high. The could separated gap up 8°, underwent successive steps. Initial showed strong dependence on relative contrasts these this always highly (WTA), regardless whether moved direction. When directions purely local: 1° approximated linear sum grating alone. On other hand, direction global: even 8°—the largest separation tried—OFRs still substantially less predicted sum. motions direction, postulate interactions: local (resulting WTA) global divisive normalization). Motion whose totally opponent rendered invisible normalization, suggesting responsible WTA behavior here occur earlier stage neural processing normalization.