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Senosory neurons manifest pronounced changes in excitability during maturation, but the factors contributing to this ubiquitous developmental phenomenon are not well understood. To assess the contribution of intrinsic membrane properties to such changes in excitability, in the present study whole cell patch-clamp recordings were made from developing(More)
1. The contrast sensitivity of the cat as a function of the spatial frequency of the visual stimulus was determined by using behavioural techniques.2. No statistically significant difference was found for the contrast sensitivity thresholds at various orientations of the stimulus.3. A comparison of the contrast sensitivity curve of the cat with that of the(More)
1. In seventy-six penetrations through areas 17 and 18 of the cat, neurones were regularly sampled at intervals of 100 micrometers and preferred orientation, optimal spatial frequency and resolving power were determined for each neurone in response to drifting sinusoidal gratings. 2. As already shown for area 17, in tangential penetrations through area 18,(More)
The mammalian retina, like the rest of the central nervous system, is highly stable and can maintain its structure and function for the full life of the individual, in humans for many decades. Photoreceptor dystrophies are instances of retinal instability. Many are precipitated by genetic mutations and scores of photoreceptor-lethal mutations have now been(More)
Experiments have been performed on unanaesthetized and paralysed cats. The tuning curves for spatial frequency of retinal, lateral geniculate and simple and complex cells of the cortex have been determined in response to sinusoidal gratings of various spatial frequencies at different levels of mean luminance. For all neurones, decreasing the mean luminance(More)
Electroretinographic responses (ERG) to homogeneous light flashes and to alternating gratings were recorded from either eye of monkeys in which one optic nerve had been previously sectioned. Three weeks after optic nerve section the ERG response of the operated eye to alternating gratings was drastically reduced in amplitude and 5 weeks after surgery it was(More)
The dendrites of ganglion cells initially ramify throughout the inner plexiform layer of the developing retina before becoming stratified into ON or OFF sublaminae. This ontogenetic event is thought to depend on glutamate-mediated afferent activity, because treating the developing retina with the glutamate analog 2-amino-4-phosphonobutyrate (APB), which(More)
Interocular alignment was assessed by corneal light reflex photography in 15 normal and 26 strabismic kittens. Strabismus was induced at 3-4 weeks of age by severing one extraocular muscle (tenotomy), by cutting and reinserting the muscle at another position on the ocular globe (recession), or by combining recession of the medial rectus muscle with(More)
The spatial and temporal response properties of neurones of areas 17 and 18 were studied in single units (165) of anaesthetized and paralysed cats. The visual stimuli were drifting or alternating gratings. We confirmed and extended the observation by Tolhurst & Movshon (1975) showing that the spatial-frequency characteristics of neurones of area 17 are(More)