This paper introduces a new technique for the analysis of chromatic properties neurones, and applies it to cells in lateral geniculate nucleus (l.g.n.) macaque. The method exploits fact that any cell combines linearly signals from cones there is restricted set lights which equally sensitive, whose members can be exchanged one another without evoking response. Stimuli are represented three‐dimensional space defined by an axis along only luminance varies, change chromaticity, 'constant B'...

The discharges of single neurones in the parvocellular and magnocellular laminae macaque's lateral geniculate nucleus (l.g.n.) were recorded with glass‐insulated tungsten micro‐electrodes. Linearity spatial summation was examined using test devised by Hochstein & Shapley (1976). 2 272 units 6 105 showed clearly non‐linear summation. A quantitative index non‐linearity did not suggest existence a distinct 'non‐linear' class unit. Spatial contrast sensitivity to moving gratings measured...

1. The discharges of single X and Y ganglion cells (distinguished by a test linearity spatial summation) were recorded in the optic tract anaesthetized, paralysed cats. 2. Fourier techniques used to analyse distribution amplitudes several component temporal frequencies maintained discharge. distinguished their mean rates, but not amplitude or variability other frequencies. 3. Sensitivities moving sinusoidal gratings measured an automatic procedure which stimulus contrast was adjusted give...

1. Extracellular recordings were obtained from units in the dorsal lateral geniculate nucleus of anaesthetized cats. 2. Of sixty‐nine units, sixty‐three could be unambiguously identified as either X (n = 33) or Y 30) by testing presence a null response to stationary sine wave gratings presented different spatial phases. 3. In flashed on and off, cells exhibited bigger, more transient responses than cells. 4. All but few shift effect (modulated periphery effect). 5. drifting frequencies,...

1. Action potentials were recorded from optic nerve fibres of lightly anaesthetized cats while parts the retina remote receptive field stimulated by a shifting grating. 2. Vigorous responses can be obtained under these conditions, confirming McIlwain (1966), Krüger & Fischer (1973), and others. 3. These 'shift responses' are not caused fluctuations stray light because (a) they cannot reduced deliberately increasing or decreasing falling on synchronously with grating; (b) steady adapting...

It is well established that the responses of neurons in lateral geniculate nucleus (LGN) can be modulated by feedback from visual cortex, but it still unclear how cortico-geniculate afferents regulate flow information to cortex primate. Here we report effects, on gain LGN neurons, differentially stimulating extraclassical receptive field, with striate intact or inactivated marmoset monkey, Callithrix jacchus . A horizontally oriented grating optimal size, spatial frequency, and temporal...

1. Single units were recorded in the striate cortex of kittens aged between 2 and 12 weeks. Contrast sensitivity measurements made using moving sinusoidal gratings used to construct spatial‐frequency tuning curves. 2. In young cells had low sensitivities, responded only spatial frequencies unselective for frequency. addition 30% youngest unresponsive visual stimuli. 3. Sensitivity improved near‐adult values within 5‐6 4. Best frequency more gradually, so that even oldest best lower than...

1. Responses to stimulation of retinal regions remote from the classical receptive field were recorded optic tract fibres in lightly anaesthetized cats. 2. X‐ and Y‐cells gave reliably different responses sudden reversal phase a high contrast grating that fell on retina more than 15 deg centre field. 3. The mechanism generates these ('shift effect' or 'periphery effect') is insensitive spatial stimulating grating. It can resolve gratings higher frequency be resolved by mechanisms but its...

1. Extracellular recordings were made from the dorsal lateral geniculate nucleus of monocularly deprived, dark‐reared and normal cats. The spatial temporal properties neurones studied. 2. mean acuity X‐cells with receptive fields 3 degrees area centralis was 3.9 c/degree for deprived eye cells cats, compared 3.8 cells. 3. activity within 4 4.3 a cat 4.0 cat. 4. peak response rates to their best frequency determined. values normal, populations all similar. 5 Measurement tuning number made....

A plaid pattern is formed when two sinusoidal gratings of different orientations are added together. Previous work has shown that V1 neurons selectively encode the direction and orientation component in a moving but not itself ( Movshon et al. 1985 ). We recorded responses 49 direction-selective to patterns area anesthetized marmoset monkey Callithrix jacchus). The rectangular patches varying lengths widths containing optimal spatial frequency were used measure size aspect ratio...