Linear and Nonlinear Contributions to the Visual Sensitivity of Neurons in Primate Lateral Geniculate Nucleus

2010 ◽  
Vol 104 (4) ◽  
pp. 1884-1898 ◽  
Author(s):  
Samuel G. Solomon ◽  
Chris Tailby ◽  
Soon K. Cheong ◽  
Aaron J. Camp
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Visual Processing ◽  
Receptive Fields ◽  
Cell Types ◽  
Visual Sensitivity ◽  
M Cells ◽  
Uniform Field ◽  
Lateral Geniculate ◽  
Linear And Nonlinear ◽  
Nonlinear Components

Several parallel pathways convey retinal signals to the visual cortex of primates. The signals of the parvocellular (P) and magnocellular (M) pathways are well characterized; the properties of other rarely encountered cell types are distinctive in many ways, but it is not clear that they can provide signals with the same fidelity. Here we study this by characterizing the temporal receptive field of neurons in the lateral geniculate nucleus of anesthetized marmosets. For each neuron, we measured the response to a flickering uniform field, and, from this, estimated the linear and nonlinear receptive fields using spike-triggered average (STA) and spike-triggered covariance (STC) analyses. As expected the response of most P-cells was dominated by the STA, but the response of most M-cells required additional nonlinear components, and these usually acted to suppress cell responses. The STC analysis showed stronger suppressive axes in suppressed-by-contrast cells, and both suppressive and excitatory axes in on-off cells. Together, the STA and the STC analyses form a model of the temporal response to a large uniform field: under this model, the information that was provided by suppressed-by-contrast cells or on-off cells approached that provided by the P- and M-cells. However, whereas P- and M-cells provided more information about luminance, the nonlinear cells provided more information about the contrast energy. This suggests that the nonlinear cells provide complimentary signals to those of P- and M-cells, with reasonably high fidelity, and may play an important role in normal visual processing.

Response properties of cells in rabbit's lateral geniculate nucleus during reversible blockade of retinal on-center channel

1983 ◽  
Vol 50 (5) ◽  
pp. 1236-1245 ◽  
Author(s):  
A. G. Knapp ◽  
L. A. Mistler
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Visual Information ◽  
Single Cells ◽  
Receptive Fields ◽  
Uniform Field ◽  
Vertebrate Species ◽  
Response Properties ◽  
Lateral Geniculate ◽  
Functional Classes ◽  
On And Off Pathways

In the vertebrate retina, visual information is segregated into an on channel excited by light increment and a complementary off channel excited by light decrement. We used 2-amino-4-phosphonobutyric acid (APB), which selectively blocks the on channel in the retina (29), to determine the contributions of the on and off pathways to response properties of neurons in the lateral geniculate nucleus (LGN) of anesthetized, paralyzed rabbits. Visually evoked responses were recorded from 46 single cells in the LGN before, during, and after vitreal perfusion with 200-1,000 microM APB. APB reversibly blocked responses of on uniform-field cells and on center concentric-field cells to stationary, flashing spots of light. Responses to off uniform-field cells and off-center concentric-field cells were largely unaffected. APB did not differentially affect responses elicited from the receptive-field centers, as opposed to the surrounds, of on-center concentric-field cells. This finding suggests that these cells are driven exclusively by the on retinal channel and that the center-surround organization of their receptive fields does not result from a convergence of the on and off pathways. We studied a small number of cells that were selective for stimulus direction or motion. In each case, APB eliminated the cell's response to a moving light edge. The surviving response to a moving dark edge retained its original direction or motion preference, suggesting that these response properties do not depend critically on interactions between the on and the off pathways. The findings obtained in the rabbit are reminiscent of the results of similar investigations in the cat (10, 11) and the monkey (25). Taken together, they indicate that in the LGN of several vertebrate species there is a precise segregation vertebrate species there is a precise segregation of on and off information, at least for some functional classes of cells. The combination of on and off information does not seem to play a major role in establishing the response properties observed at this level in the visual system.

Contrast-Dependent Spatial Summation in the Lateral Geniculate Nucleus and Retina of the Cat

2004 ◽  
Vol 92 (3) ◽  
pp. 1708-1717 ◽  
Author(s):  
M. J. Nolt ◽  
R. D. Kumbhani ◽  
L. A. Palmer
Keyword(s):  
Spatial Frequency ◽  
Lateral Geniculate Nucleus ◽  
Frequency Tuning ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Cell Types ◽  
Retinal Ganglion ◽  
Difference Of Gaussians ◽  
Lateral Geniculate

Based on extracellular recordings from 69 lateral geniculate nucleus (LGN) cells in the anesthetized cat, we found spatial summation within their receptive fields to be dependent on the contrast of the stimuli presented. By fitting the summation curves to a difference of Gaussians model, we attributed this contrast-dependent effect to an actual change in the size of the center mechanism. Analogous changes in spatial frequency tuning were also observed, specifically increased peaks and cut-off frequencies with contrast. These effects were seen across the populations of both X and Y cell types. In a few cases, LGN cells were recorded simultaneously with one of their retinal ganglion cell (RGC) inputs (S-potentials). In every case, the RGCs exhibited similar contrast-dependent effects in the space and spatial-frequency domains. We propose that this contrast dependency in the retinal ganglion cells results directly from a reduction in the size of the center mechanism due to an increase in contrast. We also propose that these properties first arise in the retina and are transmitted passively through the LGN to visual cortex.

scholarly journals Contrast Sensitivity Is Enhanced by Expansive Nonlinear Processing in the Lateral Geniculate Nucleus

2008 ◽  
Vol 99 (1) ◽  
pp. 367-372 ◽  
Author(s):  
Thang Duong ◽  
Ralph D. Freeman
Keyword(s):  
Visual Cortex ◽  
Lateral Geniculate Nucleus ◽  
Visual Processing ◽  
Linear Prediction ◽  
Visual Pathway ◽  
Low Contrast ◽  
Response Data ◽  
Lateral Geniculate ◽  
Nonlinear Processing ◽  
Contrast Response

The firing rates of neurons in the central visual pathway vary with stimulus strength, but not necessarily in a linear manner. In the contrast domain, the neural response function for cells in the primary visual cortex is characterized by expansive and compressive nonlinearities at low and high contrasts, respectively. A compressive nonlinearity at high contrast is also found for early visual pathway neurons in the lateral geniculate nucleus (LGN). This mechanism affects processing in the visual cortex. A fundamentally related issue is the possibility of an expansive nonlinearity at low contrast in LGN. To examine this possibility, we have obtained contrast–response data for a population of LGN neurons. We find for most cells that the best-fit function requires an expansive component. Additionally, we have measured the responses of LGN neurons to m-sequence white noise and examined the static relationship between a linear prediction and actual spike rate. We find that this static relationship is well fit by an expansive nonlinear power law with average exponent of 1.58. These results demonstrate that neurons in early visual pathways exhibit expansive nonlinear responses at low contrasts. Although this thalamic expansive nonlinearity has been largely ignored in models of early visual processing, it may have important consequences because it potentially affects the interpretation of a variety of visual functions.

Linear and nonlinear components of human electroretinogram

1984 ◽  
Vol 51 (5) ◽  
pp. 952-967 ◽  
Author(s):  
C. L. Baker ◽  
R. F. Hess
Keyword(s):  
Steady State ◽  
Spatial Frequency ◽  
Step Response ◽  
Linear Component ◽  
Fast Wave ◽  
Uniform Field ◽  
Nonlinear Component ◽  
Symmetric Component ◽  
Linear And Nonlinear ◽  
Nonlinear Components

We compared electroretinographic (ERG) responses to uniform-field and a variety of pattern stimuli using both transient and steady-state analyses. Evidence is provided that for all of these stimuli, the peak at high temporal frequencies in the steady-state response corresponds to the fast wave of the transient response and that the peak at low temporal frequencies corresponds to the slow wave of the step response. A variety of contrast-modulated grating stimuli were used to demonstrate that the fast, high-frequency response can be regarded as the sum of two components, an "odd-symmetric" component, which behaves linearly and is independent of spatial frequency, and an "even-symmetric" component, which behaves nonlinearly and has a band-pass spatial-frequency dependence. The prevailing distinction that is made between pattern and uniform-field ERGs is a consequence of the fact that the uniform-field ERG is dominated by the odd-symmetric (linear) component, whereas the so-called pattern (contrast reversal) ERG reveals the even-symmetric (nonlinear) component in isolation. Since a uniform field can also drive the nonlinear component, the present dichotomy ("luminance" versus "pattern") can be better understood in terms of the linear and nonlinear components of the response rather than in terms of the stimuli that produce them.

Spatial limits of epileptogenic cortex: its relationship to ectopic spike generation

1975 ◽  
Vol 38 (2) ◽  
pp. 395-404 ◽  
Author(s):  
A. J. Gabor ◽  
R. P. Scobey
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Direct Effect ◽  
Receptive Fields ◽  
Spike Generation ◽  
Lateral Geniculate

In order to investigate if ectopic spike generation was ubiquitous in and specific generation was ubiquitous in and specific to epileptogenic cortex, a method was devised to determine the limits of such an area based on a well-accepted physiologic characteristic of epileptogenicity. The limits of the penicillin-induced epileptogenic cortex were defined in terms of a retinal activation field; this is a circumscribed area whose stimulation by light evokes a characteristic cortical epileptiform wave. All lateral geniculate nucleus (LGN) neurons manifesting ectopic spike generation during interictal epileptiform waves had receptive fields within the activation field. During organized seizures, ectopic spike generation was observed in neurons with receptive fields outside the activation field. Because of these findings it was concluded that ectopic spike generation is a characteristic and specific feature of epileptogenic cortex and that it is a characteristic of the epeleptogenic process rather than a peripheral event related entirely to the direct effect of penicillin on neurons.

Mathematical models for the spatial receptive-field organization of nonlagged X-cells in dorsal lateral geniculate nucleus of cat

2000 ◽  
Vol 17 (6) ◽  
pp. 871-885 ◽  
Author(s):  
G.T. EINEVOLL ◽  
P. HEGGELUND
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Lateral Geniculate Nucleus ◽  
Discrete Model ◽  
Receptive Fields ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Retinal Ganglion ◽  
Lateral Geniculate ◽  
X Cells ◽  
Dorsal Lateral Geniculate

Spatial receptive fields of relay cells in dorsal lateral geniculate nucleus (dLGN) have commonly been modeled as a difference of two Gaussian functions. We present alternative models for dLGN cells which take known physiological couplings between retina and dLGN and within dLGN into account. The models include excitatory input from a single retinal ganglion cell and feedforward inhibition via intrageniculate interneurons. Mathematical formulas describing the receptive field and response to circular spot stimuli are found both for models with a finite and an infinite number of ganglion-cell inputs to dLGN neurons. The advantage of these models compared to the common difference-of-Gaussians model is that they, in addition to providing mathematical descriptions of the receptive fields of dLGN neurons, also make explicit contributions from the geniculate circuit. Moreover, the model parameters have direct physiological relevance and can be manipulated and measured experimentally. The discrete model is applied to recently published data (Ruksenas et al., 2000) on response versus spot-diameter curves for dLGN cells and for the retinal input to the cell (S-potentials). The models are found to account well for the results for the X-cells in these experiments. Moreover, predictions from the discrete model regarding receptive-field sizes of interneurons, the amount of center-surround antagonism for interneurons compared to relay cells, and distance between neighboring retinal ganglion cells providing input to interneurons, are all compatible with data available in the literature.

scholarly journals Spatial receptive fields in the retina and dorsal lateral geniculate nucleus of mice lacking rods and cones

2015 ◽  
Vol 114 (2) ◽  
pp. 1321-1330 ◽  
Author(s):  
Christopher A. Procyk ◽  
Cyril G. Eleftheriou ◽  
Riccardo Storchi ◽  
Annette E. Allen ◽  
Nina Milosavljevic ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Lateral Geniculate Nucleus ◽  
Visual Information ◽  
Spatial Information ◽  
Receptive Fields ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Multielectrode Arrays ◽  
Rods And Cones ◽  
Lateral Geniculate ◽  
Dorsal Lateral Geniculate

In advanced retinal degeneration loss of rods and cones leaves melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) as the only source of visual information. ipRGCs drive non-image-forming responses (e.g., circadian photoentrainment) under such conditions but, despite projecting to the primary visual thalamus [dorsal lateral geniculate nucleus (dLGN)], do not support form vision. We wished to determine what precludes ipRGCs supporting spatial discrimination after photoreceptor loss, using a mouse model ( rd/rd cl) lacking rods and cones. Using multielectrode arrays, we found that both RGCs and neurons in the dLGN of this animal have clearly delineated spatial receptive fields. In the retina, they are typically symmetrical, lack inhibitory surrounds, and have diameters in the range of 10–30° of visual space. Receptive fields in the dLGN were larger (diameters typically 30–70°) but matched the retinotopic map of the mouse dLGN. Injections of a neuroanatomical tracer (cholera toxin β-subunit) into the dLGN confirmed that retinotopic order of ganglion cell projections to the dLGN and thalamic projections to the cortex is at least superficially intact in rd/rd cl mice. However, as previously reported for deafferented ipRGCs, onset and offset of light responses have long latencies in the rd/rd cl retina and dLGN. Accordingly, dLGN neurons failed to track dynamic changes in light intensity in this animal. Our data reveal that ipRGCs can convey spatial information in advanced retinal degeneration and identify their poor temporal fidelity as the major limitation in their ability to provide information about spatial patterns under natural viewing conditions.

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