Development of the optokinetic response in macaques: a comparison with cat and man
C. Distler & K.-P. Hoffmann
Ann.N.Y.Acad.Sci., 1004: 10-18, 2003
- In macaque monkeys, an optokinetic response (OKR) can be elicited monocularly both in temporonasal and, albeit
weaker, in nasotemporal direction very early after birth. The further maturation of equal strengths of OKR in both
directions depends on stimulus velocity: at low-stimulus velocities (10-20 degrees /s) symmetry is reached at 3-4
weeks of age, at higher-stimulus velocities (40-80 degrees /s) it is reached only at 4-5 months of age. Retinal
slip neurons in the NOT-DTN are direction selective for ipsiversive stimulus movement shortly after birth. Most
of these neurons receive input from both eyes; many are dominated by the contralateral eye. Electrophysiological
and neuroanatomical evidence suggests that the cortical input to the NOT-DTN starts to become functional by postnatal
day 14, at the latest. Based on these behavioral and physiological data, as well as on comparison with data from
kittens and human infants, we hypothesize that the very early monocularly elicited bidirectional optokinetic response
is due to the direct retinal input from both eyes to the NOT-DTN. As the cortical projection matures, it gains
more and more influence upon the response properties of retinal slip neurons in the NOT-DTN, and the retinal influence
gradually decreases.
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