scholarly journals Efficient coding correlates with spatial frequency tuning in a model of V1 receptive field organization

2009 ◽  
Vol 26 (1) ◽  
pp. 157-157 ◽  
Author(s):  
JAN WILTSCHUT ◽  
FRED H. HAMKER
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Frequency Tuning ◽  
Efficient Coding ◽  
Spatial Frequency Tuning ◽  
Field Organization ◽  
Receptive Field Organization

Contrast-Dependent Changes in Spatial Frequency Tuning of Macaque V1 Neurons: Effects of a Changing Receptive Field Size

2002 ◽  
Vol 88 (3) ◽  
pp. 1363-1373 ◽  
Author(s):  
Michael P. Sceniak ◽  
Michael J. Hawken ◽  
Robert Shapley
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Frequency Tuning ◽  
Fundamental Property ◽  
Spatial Summation ◽  
Field Size ◽  
Stimulus Contrast ◽  
Tuning Curves ◽  
Spatial Frequency Tuning ◽  
Receptive Field Organization

Previous studies on single neurons in primary visual cortex have reported that selectivity for orientation and spatial frequency tuning do not change with stimulus contrast. The prevailing hypothesis is that contrast scales the response magnitude but does not differentially affect particular stimuli. Models where responses are normalized over contrast to maintain constant tuning for parameters such as orientation and spatial frequency have been proposed to explain these results. However, our results indicate that a fundamental property of receptive field organization, spatial summation, is not contrast invariant. We examined the spatial frequency tuning of cells that show contrast-dependent changes in spatial summation and have found that spatial frequency selectivity also depends on stimulus contrast. These results indicate that contrast changes in the spatial frequency tuning curves result from spatial reorganization of the receptive field.

Efficient coding correlates with spatial frequency tuning in a model of V1 receptive field organization

2009 ◽  
Vol 26 (1) ◽  
pp. 21-34 ◽  
Author(s):  
JAN WILTSCHUT ◽  
FRED H. HAMKER
Keyword(s):  
Experimental Data ◽  
Receptive Field ◽  
Visual Processing ◽  
Hebbian Learning ◽  
Frequency Tuning ◽  
Receptive Fields ◽  
Efficient Coding ◽  
Early Visual Processing ◽  
Field Organization ◽  
Receptive Field Organization

AbstractEfficient coding has been proposed to play an essential role in early visual processing. While several approaches used an objective function to optimize a particular aspect of efficient coding, such as the minimization of mutual information or the maximization of sparseness, we here explore how different estimates of efficient coding in a model with nonlinear dynamics and Hebbian learning determine the similarity of model receptive fields to V1 data with respect to spatial tuning. Our simulation results indicate that most measures of efficient coding correlate with the similarity of model receptive field data to V1 data, that is, optimizing the estimate of efficient coding increases the similarity of the model data to experimental data. However, the degree of the correlation varies with the different estimates of efficient coding, and in particular, the variance in the firing pattern of each cell does not predict a similarity of model and experimental data.

Receptive Field Size and Response Latency Are Correlated Within the Cat Visual Thalamus

2005 ◽  
Vol 93 (6) ◽  
pp. 3537-3547 ◽  
Author(s):  
Chong Weng ◽  
Chun-I Yeh ◽  
Carl R. Stoelzel ◽  
Jose-Manuel Alonso
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Response Latency ◽  
Time Course ◽  
Frequency Tuning ◽  
Receptive Fields ◽  
Cortical Cell ◽  
Field Size ◽  
Receptive Field Size ◽  
Spatial Frequency Tuning

Each point in visual space is encoded at the level of the thalamus by a group of neighboring cells with overlapping receptive fields. Here we show that the receptive fields of these cells differ in size and response latency but not at random. We have found that in the cat lateral geniculate nucleus (LGN) the receptive field size and response latency of neighboring neurons are significantly correlated: the larger the receptive field, the faster the response to visual stimuli. This correlation is widespread in LGN. It is found in groups of cells belonging to the same type (e.g., Y cells), and of different types (i.e., X and Y), within a specific layer or across different layers. These results indicate that the inputs from the multiple geniculate afferents that converge onto a cortical cell (approximately 30) are likely to arrive in a sequence determined by the receptive field size of the geniculate afferents. Recent studies have shown that the peak of the spatial frequency tuning of a cortical cell shifts toward higher frequencies as the response progresses in time. Our results are consistent with the idea that these shifts in spatial frequency tuning arise from differences in the response time course of the thalamic inputs.

Comparison of response properties of cells in the cat's visual cortex at high and low luminance levels

1985 ◽  
Vol 54 (1) ◽  
pp. 61-72 ◽  
Author(s):  
A. S. Ramoa ◽  
R. D. Freeman ◽  
A. Macy
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Cortical Neurons ◽  
Ganglion Cells ◽  
Scattered Light ◽  
Cortical Cells ◽  
Response Properties ◽  
Low Luminance ◽  
Field Organization ◽  
Receptive Field Organization

Receptive-field organization of cells in the cat's striate cortex and lateral geniculate nucleus (LGN) was investigated by using bars of light as stimuli. The aim was to determine if differences occur between conditions of high and low luminance levels. Of 72 cortical cells studied, the receptive fields of 63 were clearly different at high compared with low luminances. Units that gave on-off responses to flashed bars, for example, typically displayed on-only responses at low luminance. By far the most frequent change was that off responses were reduced or absent at low luminance levels. Of 63 cells that showed clear changes, 54 were of this type. This altered receptive-field organization appears to remain for extended periods (we have monitored the steady-state case for up to 2 h). Additional tests allow us to rule out the possible influence of overall changes in response strength and scattered light. To see if similar changes in receptive-field organization are present at the level of the LGN, we recorded from a small number of cells in the LGN (n = 10) and from an additional five afferent fibers in the cortex. In each case, there was a change in center-surround organization between high and low luminance levels similar to that previously reported for retinal ganglion cells. The excitatory responses from the surround for both on-center and off-center cells were absent at low luminance. Taken together, the results suggest that surround responses that can be elicited from ganglion cells and LGN cells make an important contribution to the receptive-field organization of cortical neurons. Changes in receptive-field organization of cortical cells are apparently not accompanied by alterations of other basic response properties. Orientation (7 cells) and spatial frequency (53 cells) selectivity remain relatively unchanged when measured at different luminances. Although optimal spatial frequency is slightly lower at low luminance levels, the low spatial frequency attenuation remains unaltered. Since receptive-field changes between high and low luminance levels suggest that a unit's classification may also vary, we examined simple and complex cell characteristics using sinusoidal gratings (65 cells). Contrary to what we had anticipated, the degree of modulation of responses was relatively independent of luminance, indicating that cell classification does not vary with stimulus luminance.

Organization of suppression in receptive fields of neurons in cat visual cortex

1992 ◽  
Vol 68 (1) ◽  
pp. 144-163 ◽  
Author(s):  
G. C. DeAngelis ◽  
J. G. Robson ◽  
I. Ohzawa ◽  
R. D. Freeman
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Spatial Frequency ◽  
Frequency Tuning ◽  
Suppressive Effect ◽  
Preferred Orientation ◽  
Maximal Response ◽  
Spatial Phase ◽  
Spatial Frequency Tuning ◽  
Maximal Suppression

1. The response to an optimally oriented stimulus of both simple and complex cells in the cat's striate visual cortex (area 17) can be suppressed by the superposition of an orthogonally oriented drifting grating. This effect is referred to as cross-orientation suppression. We have examined the spatial organization and tuning characteristics of this suppressive effect with the use of extracellular recording techniques. 2. For a total of 75 neurons, we have measured the size of each cell's excitatory receptive field by use of rectangular patches of drifting sinusoidal gratings presented at the optimal orientation and spatial frequency. The length and width of these grating patches are varied independently. Receptive-field length and width are determined from the dimensions of the smallest grating patch required to elicit a maximal response. 3. The extent of the area from which cross-orientation suppression originates has been measured in an analogous manner. Each neuron is excited by a patch of drifting grating the same size as the receptive field. The response to this stimulus is modulated by a superimposed patch of grating having an orthogonal orientation. After selecting the spatial frequency that produces maximal suppression, the response of each cell is examined as a function of the length and width of the orthogonal (suppressive) grating patch. Results from 29 cells show that the dimensions of the orthogonal grating patch required to elicit maximal suppression are similar to, or smaller than, the dimensions of the excitatory receptive field. Thus cross-orientation suppression originates from within the receptive field. 4. For some cells the spatial frequency tuning of the suppressive effect is much broader than the spatial frequency tuning for excitation. In these cases it is possible to find a spatial frequency that produces suppression but not excitation. With the use of a suppressive stimulus having this spatial frequency, we examined the strength of suppression as a function of orientation for 11 cells. These tests show that suppression occurs at all orientations, including the preferred orientation for excitation. In some cases, suppression is somewhat stronger at the preferred orientation for excitation than at any other orientation. 5. For 12 cells we varied the relative spatial phase between the optimally oriented and orthogonal gratings. In all cases the magnitude of suppression is largely independent of the relative spatial phase. 6. For three binocular cells we examined whether the suppressive effect of a grating oriented orthogonal to the optimum could be mediated dichoptically.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of rearing kittens with convergent strabismus on development of receptive-field properties in striate cortex neurons

1983 ◽  
Vol 50 (1) ◽  
pp. 265-286 ◽  
Author(s):  
Y. M. Chino ◽  
M. S. Shansky ◽  
W. L. Jankowski ◽  
F. A. Banser
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Striate Cortex ◽  
Frequency Tuning ◽  
Tuning Curves ◽  
Spatial Frequency Tuning ◽  
Receptive Field Properties ◽  
Convergent Strabismus ◽  
Striate Neurons ◽  
Contrast Thresholds

Convergent strabismus was induced surgically in seven kittens at 3 wk of age. Recordings were made in 131 cells in the striate cortex of these strabismic kittens after maturation, and the results were compared to the data obtained from 140 striate neurons in normally reared cats. All our samples had receptive fields (RFs) within 5 degrees of the area centralis. The spatial and temporal response properties were quantitatively analyzed by using drifting sinusoidal gratings of various contrasts as well as spatial and temporal frequencies. In contrast to other reports, the receptive-field properties of the striate neurons exclusively driven or dominated by the deviating eye were quite abnormal. The spatial frequency tuning curves in strabismic cats were different from those obtained from normals in that the optimal spatial frequencies and spatial resolutions were shifted to lower values and the bandwidths were significantly broader. The contrast-response functions show that contrast thresholds, measured at the optimal spatial frequency, were significantly higher and the slope of the functions much flatter in strabismic animals. Moreover, receptive-field sizes were much larger and the sharpness of orientation tuning was reduced in strabismic cats. Direction selectivity, however, was normal in those animals. The temporal frequency tuning curves were also abnormal, particularly in that temporal resolution was considerably reduced in strabismic cats compared with normally reared cats. In addition, many cells in strabismic animals exhibited much longer latencies to visual and optic chiasm (OX) stimulations. All these effects, to our great surprise, were also observed in the striate units controlled by the nondeviating eye, although the magnitude of the alteration depends on the receptive-field property. The abnormalities found in spatial frequency tuning, contrast thresholds, and RF sizes were as severe as those revealed in the deviating eye. On the other hand, the effects on other RF properties were minimal or less severe. These physiological findings correspond very well with results from behavioral measurements of spatial contrast sensitivity in the same cats reported elsewhere. It is concluded from these results that the nondeviating eye in convergent strabismic animals, and perhaps humans, should not always be presumed "normal."

Comparison of the responses of AII amacrine cells in the dark- and light-adapted rabbit retina

1999 ◽  
Vol 16 (4) ◽  
pp. 653-665 ◽  
Author(s):  
DAIYAN XIN ◽  
STEWART A. BLOOMFIELD
Keyword(s):  
Receptive Field ◽  
Light Adaptation ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Rabbit Retina ◽  
Response Component ◽  
Synaptic Inputs ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Aii Amacrine Cells

We studied the light-evoked responses of AII amacrine cells in the rabbit retina under dark- and light-adapted conditions. In contrast to the results of previous studies, we found that AII cells display robust responses to light over a 6–7 log unit intensity range, well beyond the operating range of rod photoreceptors. Under dark adaptation, AII cells showed an ON-center/OFF-surround receptive-field organization. The intensity–response profile of the center-mediated response component followed a dual-limbed sigmoidal function indicating a transition from rod to cone mediation as stimulus intensities were increased. Following light adaptation, the receptive-field organization of AII cells changed dramatically. Light-adapted AII cells showed both ON- and OFF-responses to stimulation of the center receptive field, but we found no evidence for an antagonistic surround. Interestingly, the OFF-center response appeared first following rapid light adaptation and was then replaced gradually over a 1–4 min period by the emerging ON-center response component. Application of the metabotropic glutamate receptor agonist APB, the ionotropic glutamate blocker CNQX, 8-bromo-cGMP, and the nitric oxide donor SNAP all showed differential effects on the various center-mediated responses displayed by dark- and light-adapted AII cells. Taken together, these pharmacological results indicated that different synaptic circuits are responsible for the generation of the different AII cell responses. Specifically, the rod-driven ON-center responses are apparently derived from rod bipolar cell synaptic inputs, whereas the cone-driven ON-center responses arise from signals crossing the gap junctions between AII cells and ON-center cone bipolar cells. Additionally, the OFF-center response of light-adapted AII cells reflects direct synaptic inputs from OFF-center cone bipolar cells to AII dendritic processes in the distal inner plexiform layer.

Role of intrathalamic inhibition on the spatial frequency tuning of neurons in the lateral geniculate nucleus of the cat

2009 ◽  
Vol 65 ◽  
pp. S106
Author(s):  
Akihiro Kimura ◽  
Satoshi Shimegi ◽  
Shin-ichiro Hara ◽  
Masahiro Okamoto ◽  
Hiromichi Sato
Keyword(s):  
Spatial Frequency ◽  
Lateral Geniculate Nucleus ◽  
Frequency Tuning ◽  
Spatial Frequency Tuning ◽  
Lateral Geniculate

Adaptation in single units in visual cortex: The tuning of aftereffects in the spatial domain

1989 ◽  
Vol 2 (6) ◽  
pp. 593-607 ◽  
Author(s):  
A. B. Saul ◽  
M. S. Cynader
Keyword(s):  
Spatial Frequency ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Cortical Cell ◽  
Selective Adaptation ◽  
Single Units ◽  
Spatial Frequency Tuning ◽  
Sinusoidal Gratings ◽  
A Cell ◽  
Drift Direction

AbstractCat striate cortical neurons were investigated using a new method of studying adaptation aftereffects. Stimuli were sinusoidal gratings of variable contrast, spatial frequency, and drift direction and rate. A series of alternating adapting and test trials was presented while recording from single units. Control trials were completely integrated with the adapted trials in these experiments.Every cortical cell tested showed selective adaptation aftereffects. Adapting at suprathreshold contrasts invariably reduced contrast sensitivity. Significant aftereffects could be observed even when adapting at low contrasts.The spatial-frequency tuning of aftereffects varied from cell to cell. Adapting at a given spatial frequency generally resulted in a broad response reduction at test frequencies above and below the adapting frequency. Many cells lost responses predominantly at frequencies lower than the adapting frequency.The tuning of aftereffects varied with the adapting frequency. In particular, the strongest aftereffects occurred near the adapting frequency. Adapting at frequencies just above the optimum for a cell often altered the spatial-frequency tuning by shifting the peak toward lower frequencies. The fact that the tuning of aftereffects did not simply match the tuning of the cell, but depended on the adapting stimulus, implies that extrinsic mechanisms are involved in adaptation effects.

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