Development of contrast sensitivity and temporal-frequency selectivity in primate lateral geniculate nucleus.
We studied the development of spatial contrast-sensitivity and temporal-frequency selectivity for neurons in the monkey lateral geniculate nucleus. During postnatal week 1, the spatial properties of P-cells and M-cells are hardly distinguishable, with low contrast-sensitivity, sluggish responses, and poor spatial resolution. The acuity of P-cells improves progressively until at least 8 months, but there is no obvious increase in their maximum contrast-sensitivity with age. The contrast sensitivity of M-cells is already clearly higher than that of P-cells by 2 months, and at 8 months of age this characteristic difference between M- and P-cells approaches the adult pattern. There is a major increase in responsiveness during the first 2 postnatal months, especially for M-cells, the peak firing rate of which rises fivefold, on average, between birth and 2 months. Many P-cells in the neonatal and 2-month-old animals did not give statistically reliable responses to achromatic gratings, even at the highest contrasts: this unresponsiveness of P-cells might result from low gain and/or chromatic opponency. The upper limit of temporal resolution in the neonate is low--about one-third of that in the adult. Among M-cells, the improvement in temporal resolution, like that in contrast sensitivity, is rapid over the first 2 months, followed by a slower change approaching the adult value by 8 months of age. The development of contrast sensitivity, responsiveness and temporal tuning are little affected, if at all, by binocular deprivation of pattern vision from birth for even a prolonged period.
Hawken
M J
MJ
University Laboratory of Physiology, Oxford University, UK. mjh@cns.nyu.edu
Blakemore
C
C
Morley
J W
JW
D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D002522:Chlorocebus aethiops; D015350:Contrast Sensitivity; D005829:Geniculate Bodies / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D008253:Macaca mulatta; D008954:Models, Biological; D009474:Neurons / Q000502:physiology; D012683:Sensory Deprivation / Q000502:physiology; D013997:Time Factors; D014785:Vision, Ocular