scholarly journals Dynamics of Spatial Resolution of Single Units in the Lateral Geniculate Nucleus of Cat During Brief Visual Stimulation

2007 ◽  
Vol 97 (2) ◽  
pp. 1445-1456 ◽  
Author(s):  
O. Ruksenas ◽  
A. Bulatov ◽  
P. Heggelund
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Spatial Resolution ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Stimulus Onset ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Lateral Geniculate ◽  
Peak Resolution ◽  
Coarse To Fine

Sharpness of vision depends on the resolution of details conveyed by individual neurons in the visual pathway. In the dorsal lateral geniculate nucleus (LGN), the neurons have receptive fields with center-surround organization, and spatial resolution may be measured as the inverse of center size. We studied dynamics of receptive field center size of single LGN neurons during the response to briefly (400–500 ms) presented static light or dark spots. Center size was estimated from a series of spatial summation curves made for successive 5-ms intervals during the stimulation period. The center was wide at the start of the response, but shrank rapidly over 50–100 ms after stimulus onset, whereupon it widened slightly. Thereby, the spatial resolution changed from coarse-to-fine with average peak resolution occurring ∼70 ms after stimulus onset. The changes in spatial resolution did not follow changes of firing rate; peak firing appeared earlier than the maximal spatial resolution. We suggest that the response initially conveys a strong but spatially coarse message that might have a detection and tune-in function, followed by transient transmission of spatially precise information about the stimulus. Experiments with spots presented inside the maximum but outside the minimum center width suggested a dynamic reduction in number of responding neurons during the stimulation; from many responding neurons initially when the field centers are large to fewer responding neurons as the centers shrink. Thereby, there is a change from coarse-to-fine also in the recruitment of responding neurons during brief static stimulation.

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.

Development of neuronal response properties in the cat dorsal lateral geniculate nucleus during monocular deprivation

1983 ◽  
Vol 50 (1) ◽  
pp. 240-264 ◽  
Author(s):  
S. C. Mangel ◽  
J. R. Wilson ◽  
S. M. Sherman
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Spatial Resolution ◽  
Optic Chiasm ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Response Properties ◽  
Lateral Geniculate ◽  
X And Y Cells ◽  
X Cells ◽  
Y Cells ◽  
Dorsal Lateral Geniculate

We measured response properties of X- and Y-cells from laminae A and A1 of the dorsal lateral geniculate nucleus of monocularly lid-sutured cats at 8, 12, 16, 24, and 52-60 wk of age. Visual stimuli consisted of small spots of light and vertically oriented sine-wave gratings counterphased at a rate of 2 cycles/s. In cats as young as 8 wk of age, nondeprived and deprived neurons could be clearly identified as X-cells or Y-cells with criteria previously established for adult animals. Nonlinear responses of Y-cells from 8- and 12-wk-old cats were often temporally labile; that is, the amplitude of the nonlinear response of nondeprived and deprived cells increased or decreased suddenly. A similar lability was not noted for the linear response component. This phenomenon rarely occurred in older cats. At 8 wk of age, Y-cell proportions (number of Y-cells/total number of cells) in nondeprived and deprived A-laminae were approximately equal. By 12 wk of age and thereafter, the proportion of Y-cells in deprived laminae was significantly lower than that in nondeprived laminae. At no age was there a systematic difference in response properties (spatial resolution, latency to optic chiasm stimulation, etc.) for Y-cells between deprived and nondeprived laminae. Spatial resolution, defined as the highest spatial frequency to which a cell would respond at a contrast of 0.6, was similar for nondeprived and deprived X-cells until 24 wk of age. In these and older cats, the mean spatial resolution of deprived X-cells was lower than that of nondeprived X-cells. This difference was noted first for lamina A1 at 24 wk of age and later for lamina A at 52-60 wk of age. The average latency of X-cells to optic chiasm stimulation was slightly greater in deprived laminae than in nondeprived laminae. No such difference was seen for Y-cells. Cells with poor and inconsistent responses were encountered infrequently but were observed far more often in deprived laminae than in nondeprived laminae. Lid suture appears to affect the development of geniculate X- and Y-cells in very different ways. Not only is the final pattern of abnormalities quite different between these cell groups, but the developmental dynamics of these abnormalities also differ.

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.

Quantitative analyses of synaptic contacts of interneurons in the dorsal lateral geniculate nucleus of the squirrel monkey

1996 ◽  
Vol 13 (6) ◽  
pp. 1129-1142 ◽  
Author(s):  
James R. Wilson ◽  
Donna M. Forestner ◽  
Ryan P. Cramer
Keyword(s):  
Squirrel Monkey ◽  
Lateral Geniculate Nucleus ◽  
Receptive Fields ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Saimiri Sciureus ◽  
Projection Neurons ◽  
Parvocellular Pathway ◽  
Synaptic Contacts ◽  
Lateral Geniculate ◽  
Dorsal Lateral Geniculate

AbstractThree interneurons were recorded from and then injected with horseradish peroxidase in the parvocellular laminae of the squirrel monkey's (Saimiri sciureus) dorsal lateral geniculate nucleus. They were then examined using the electron microscope for their synaptic contacts, both the afferent contacts onto their dendrites and their presynaptic dendritic contacts onto presumptive projection (relay) neuron dendrites. The somata of these interneurons were small (mean = 178 μm2), but the dendritic trees were large compared with those of projection neurons. All three interneurons had similar synaptic patterns onto their dendrites with about equal numbers of retinal, cortical, and GABAergic contacts. The distribution of these contacts was more uniform compared with the same types of contacts made onto projection neurons. The presynaptic dendrites were observed to contact only the dendrites of presumptive projection neurons, and these contacts were nearly all in the form of geniculate triads. None of the three interneurons displayed an axon. The receptive fields of these interneurons were similar to those of projection cells, but were larger and had center-response signs that were the opposite of the projection neurons around them (e.g. OFF center for the dorsal part of the parvocellular mass where ON-center projection neurons reside). The squirrel monkey data provides additional evidence that one aspect of the laminar pattern observed in the parvocellular pathway of the primate's dLGN might be related to a segregation of projection neurons of one center-response sign with interneurons of the opposite center-response sign.

Response properties in the dorsal lateral geniculate nucleus of the adult cat after interruption of prenatal binocular interactions

1989 ◽  
Vol 62 (5) ◽  
pp. 1039-1051 ◽  
Author(s):  
C. A. White ◽  
L. M. Chalupa ◽  
L. Maffei ◽  
M. A. Kirby ◽  
B. Lia
Keyword(s):  
Spatial Resolution ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Field Size ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Lower Percentage ◽  
Binocular Interactions ◽  
Adult Cats ◽  
X Cells ◽  
Y Cells

1. Single-cell recordings were made in the magnocellular layer of the dorsal lateral genicule nucleus (dLGN) of five adult cats in which prenatal binocular interactions were interrupted by monocular enucleation at known gestational ages. Three cats (early enucleates) had one eye removed on either embryonic day 44.48, or 49, before retinogeniculate inputs are segregated into uniocular layers. Two other (late enucleates) underwent this procedure on embryonic days 55 and 58, when segregation is well advanced. Responses were compared with those obtained from recordings in the A and A1 layers of the dLGN of seven normal adult cats. 2. Cells were classified as ON or OFF by the use of spots of light and as X or Y based on a test of linearity of spatial summation with the use of counterphased sinusoidal gratings. Receptive-field size and spatial resolution were also obtained. 3. The dLGN of prenatally enucleated cats contains a dorsal magnocellular layer and a ventral parvocellular layer. In early enucleates, only an occasional hint of a cell-sparse interlaminar zone was apparent, located between the magnocellular and parvocellular layers. In late enucleates, a prominent cell-sparse band was observed contralateral to the remaining eye, in a region that would most likely correspond to layer A1 in the normal dLGN. No such cell-sparse band was seen ipsilateral to the remaining eye in late enucleates. 4. Eighty-six X cells and 22 Y cells were studied in the enucleates. Both cell types were found at all depths of the magnocellular layer. All but a few neurons had concentric ON-center or OFF-center receptive fields that were normal in size. The topography of receptive fields also appeared normal. In addition, spatial resolution of X and Y cells was similar in experimental and control animals. 5. In early enucleates there was a higher percentage of X cells and a lower percentage of Y cells than normal. The change in X-to-Y ratio was shown to be because of both a gain in cells with X properties and a loss of cells with Y properties. The distribution of dLGN somal sizes in the early enucleates was comparable with controls, so the change in X-to-Y ratio most likely did not result from an electrode sampling bias. It was suggested that the X-to-Y ratio difference could stem from the abnormalities in retinogeniculate terminal arbors that have been shown to follow early eye removal.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Spatial Resolution of Suprachoroidal–Transretinal Stimulation Estimated by Recording Single-Unit Activity From the Cat Lateral Geniculate Nucleus

2021 ◽  
Vol 15 ◽  
Author(s):  
Tomomitsu Miyoshi ◽  
Takeshi Morimoto ◽  
Hajime Sawai ◽  
Takashi Fujikado
Keyword(s):  
Receptive Field ◽  
Lateral Geniculate Nucleus ◽  
Spatial Resolution ◽  
Single Unit ◽  
Animal Experiments ◽  
Response Probability ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Functional Evaluation ◽  
Retinal Stimulation ◽  
Lateral Geniculate

Retinal prostheses are devices used to restore visual sensation in patients suffering from photoreceptor degeneration, such as retinitis pigmentosa. Suprachoroidal–transretinal stimulation (STS) is a prosthesis with retinal electrodes located in the sclera. STS has the advantage that it is safer than epiretinal or subretinal prostheses, as the implant is not directly attached to the retinal tissue. We have previously reported feasibility of STS with animal experiments and clinical trials. However, functional evaluation with neurophysiological experiments is still largely missing. To estimate the spatial resolution of STS, single-unit activities in response to STS were recorded from relay cells in the dorsal lateral geniculate nucleus of cats, and the response probability of the units was analyzed in relation to the distance between the stimulus location and the receptive field of each recorded unit. A platinum electrode was attached to the sclera after lamellar resection, and the return electrode was placed in the vitreous. The stimulating current, which ranged from 50 to 500 μA, was applied between these electrodes, and the probability of spike responses occurring just after retinal stimulation was measured. The distance at half-maximum of response was determined from the collected response probabilities as a function of stimulus intensity for all units characterized by their distances from the receptive field center to the stimulation point. As the stimulation became weaker, this distance decreased to 1.8° at 150 and 100 μA. As another estimation, the radius of 25% response probability was 1.4° at 100 μA. The diameter of the stimulated cat retinal area, 3.6° or 2.8°, corresponds to human visual acuity of 0.005 or 0.007, or finger counting. Considering the lower hazard to the retina of STS and its potentially large visual field coverage, STS is an attractive method for retinal prosthetic device development.

Modulatory influence of putative inhibitors of nitric oxide synthesis on visual processing in the cat lateral geniculate nucleus

1994 ◽  
Vol 71 (1) ◽  
pp. 146-149 ◽  
Author(s):  
J. Cudeiro ◽  
C. Rivadulla ◽  
R. Rodriguez ◽  
S. Martinez-Conde ◽  
C. Acuna ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lateral Geniculate Nucleus ◽  
Visual Processing ◽  
Visual Information ◽  
Visual Stimulation ◽  
Discharge Rate ◽  
Substantial Reduction ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Simultaneous Application ◽  
Lateral Geniculate

1. Using an in vivo preparation we have examined the actions of two inhibitors of nitric oxide synthase (NOS), NG-nitro-L-arginine (L-NOArg) and NG-methyl-L-arginine (L-MeArg), in the feline dorsal lateral geniculate nucleus (dLGN). We compared the responses obtained to iontophoretic application of these substances during visual stimulation with those elicited by visual stimulation alone. The effects of concurrent ejection of L-arginine (L-Arg), the normal physiological substrate of NOS, and D-arginine, the inactive isomer, were tested on these responses. 2. Extracellular application of L-NOArg and L-MeArg produced clear and repeatable effects, consisting of substantial reduction in discharge rate without affecting response selectivity, on 94% of tested cells. These effects were prevented by simultaneous application of L-Arg, which when ejected alone produced no change on visual evoked responses. 3. The data suggest that nitric oxide (NO) is necessary for the transmission of the visual input under normal visual stimulation and show a direct involvement of NO in visual information processing at the level of dLGN, suggesting that its contribution to brain mechanisms is more profound than previously thought.

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.

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