scholarly journals Formation of Direction Selectivity in Natural Scene Environments

2000 ◽  
Vol 12 (5) ◽  
pp. 1057-1066 ◽  
Author(s):  
Brian Blais ◽  
Leon N. Cooper ◽  
Harel Shouval
Keyword(s):  
Principal Component Analysis ◽  
Single Cell ◽  
Striate Cortex ◽  
Principal Component ◽  
Direction Selectivity ◽  
Natural Scene ◽  
Complex Cells ◽  
Learning Rules ◽  
Simple And Complex Cells ◽  
Cat Striate Cortex

Most simple and complex cells in the cat striate cortex are both orientation and direction selective. In this article we use single-cell learning rules to develop both orientation and direction selectivity in a natural scene environment. We show that a simple principal component analysis rule is inadequate for developing direction selectivity, but that the BCM rule as well as similar higher-order rules can. We also demonstrate that the convergence of lagged and nonlagged cells depends on the velocity of motion in the environment, and that strobe rearing disrupts this convergence, resulting in a loss of direction selectivity.

Direction-selective adaptation in simple and complex cells in cat striate cortex

1988 ◽  
Vol 59 (4) ◽  
pp. 1314-1330 ◽  
Author(s):  
S. G. Marlin ◽  
S. J. Hasan ◽  
M. S. Cynader
Keyword(s):  
Cortical Neurons ◽  
Striate Cortex ◽  
Selective Adaptation ◽  
Direction Selectivity ◽  
Simple Cells ◽  
Complex Cells ◽  
Preferred Direction ◽  
Directional Preference ◽  
Simple And Complex Cells ◽  
Cat Striate Cortex

1. The selectivity of adaptation to unidirectional motion was examined in neurons of the cat striate cortex. Following prolonged stimulation with a unidirectional high-contrast grating, the responsivity of cortical neurons was reduced. In many units this decrease was restricted to the direction of prior stimulation. This selective adaptation produced changes in the degree of direction selectivity of the cortical units (as measured by the ratio of the response to motion in the preferred direction to that in the nonpreferred direction). 2. The initial strength of the directional preference of a given cortical unit did not determine the degree of direction-selective adaptation. Indeed, even non-direction-selective units could exhibit pronounced direction-selective adaptation. The degree of direction-selective adaptation was also independent of the overall decrease in responsivity during adaptation. 3. There was no difference between simple and complex cells in the total amount of adaptation observed. The selectivity of the adaptation, however, did differ between these two cell types. As a group, simple cells showed significant direction-selective adaptation, whereas complex cells did not. The directional preference of most simple cells decreased following preferred direction adaptation and many highly direction selective simple cells became non-direction selective. In addition, simple cells became significantly more direction selective following nonpreferred direction adaptation. 4. Some complex cells also demonstrated direction-selective adaptation. There was, however, much more variability among complex cells than simple cells. Some complex cells actually increased direction selectivity following preferred direction adaptation. These differences between simple and complex cells suggest that changes in direction selectivity following unidirectional adaptation are not due to simple neuronal fatigue of the unit being recorded, but depend on selective adaptation of afferent inputs to the unit. 5. The spontaneous activity of many cortical neurons decreased following preferred direction adaptation but increased following adaptation in the nonpreferred direction. The response to a stationary grating also decreased following preferred direction adaptation. However, there was very little change in the response to a stationary grating following adaptation in the nonpreferred direction.

Receptive-field characteristics of neurons in cat striate cortex: Changes with visual field eccentricity

1976 ◽  
Vol 39 (3) ◽  
pp. 512-533 ◽  
Author(s):  
J. R. Wilson ◽  
S. M. Sherman
Keyword(s):  
Visual Field ◽  
Receptive Field ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Orientation Selectivity ◽  
Simple Cells ◽  
Complex Cells ◽  
Cat Striate Cortex

1. Receptive-field properties of 214 neurons from cat striate cortex were studied with particular emphasis on: a) classification, b) field size, c) orientation selectivity, d) direction selectivity, e) speed selectivity, and f) ocular dominance. We studied receptive fields located throughtout the visual field, including the monocular segment, to determine how receptivefield properties changed with eccentricity in the visual field.2. We classified 98 cells as "simple," 80 as "complex," 21 as "hypercomplex," and 15 in other categories. The proportion of complex cells relative to simple cells increased monotonically with receptive-field eccenticity.3. Direction selectivity and preferred orientation did not measurably change with eccentricity. Through most of the binocular segment, this was also true for ocular dominance; however, at the edge of the binocular segment, there were more fields dominated by the contralateral eye.4. Cells had larger receptive fields, less orientation selectivity, and higher preferred speeds with increasing eccentricity. However, these changes were considerably more pronounced for complex than for simple cells.5. These data suggest that simple and complex cells analyze different aspects of a visual stimulus, and we provide a hypothesis which suggests that simple cells analyze input typically from one (or a few) geniculate neurons, while complex cells receive input from a larger region of geniculate neurons. On average, this region is invariant with eccentricity and, due to a changing magnification factor, complex fields increase in size with eccentricity much more than do simple cells. For complex cells, computations of this geniculate region transformed to cortical space provide a cortical extent equal to the spread of pyramidal cell basal dendrites.

scholarly journals Ascending Projections of Simple and Complex Cells in Layer 6 of the Cat Striate Cortex

1998 ◽  
Vol 18 (19) ◽  
pp. 8086-8094 ◽  
Author(s):  
Judith A. Hirsch ◽  
Christine A. Gallagher ◽  
José-Manuel Alonso ◽  
Luis M. Martinez
Keyword(s):  
Striate Cortex ◽  
Complex Cells ◽  
Simple And Complex Cells ◽  
Cat Striate Cortex

Activity of cells in area 17 of the cat in absence of input from layer a of lateral geniculate nucleus

1983 ◽  
Vol 49 (3) ◽  
pp. 595-610 ◽  
Author(s):  
J. G. Malpeli
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Orientation Selectivity ◽  
Complex Cells ◽  
Normal Orientation ◽  
Lateral Geniculate ◽  
Special Complex ◽  
Cat Striate Cortex

1. Injections of 4 mM cobaltous chloride were used to block synaptic transmission in layer A of the lateral geniculate nucleus (LGN) without blocking fibers of passage going to or arising from other layers. 2. Selective inactivation of geniculate layer A virtually abolished all visual activity in cortical layers 4ab, 4c, and 6. Under these conditions, the stimulus-evoked response, orientation selectivity, and direction selectivity of cells in layers 2 and 3 were not seriously affected. In layer 5, the effects of the block were more variable, with special complex cells least affected and simple cells most affected. 3. Since the organization of complex receptive fields and the maintenance of normal orientation selectivity in supragranular layers survive disruption of major interlaminar interactions, it appears that much of the functional architecture of cat striate cortex does not depend on the integrity of the column. 4. These results support the idea that each layer of the LGN is a functional unit with a unique pattern of access to the various layers of visual cortex.

Directional selectivity and spatiotemporal structure of receptive fields of simple cells in cat striate cortex

1991 ◽  
Vol 66 (2) ◽  
pp. 505-529 ◽  
Author(s):  
R. C. Reid ◽  
R. E. Soodak ◽  
R. M. Shapley
Keyword(s):  
Time Course ◽  
Linear Prediction ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Quantitative Measure ◽  
Direction Selectivity ◽  
Simple Cells ◽  
Preferred Direction ◽  
Orientation Contrast ◽  
Cat Striate Cortex

1. Simple cells in cat striate cortex were studied with a number of stimulation paradigms to explore the extent to which linear mechanisms determine direction selectivity. For each paradigm, our aim was to predict the selectivity for the direction of moving stimuli given only the responses to stationary stimuli. We have found that the prediction robustly determines the direction and magnitude of the preferred response but overestimates the nonpreferred response. 2. The main paradigm consisted of comparing the responses of simple cells to contrast reversal sinusoidal gratings with their responses to drifting gratings (of the same orientation, contrast, and spatial and temporal frequencies) in both directions of motion. Although it is known that simple cells display spatiotemporally inseparable responses to contrast reversal gratings, this spatiotemporal inseparability is demonstrated here to predict a certain amount of direction selectivity under the assumption that simple cells sum their inputs linearly. 3. The linear prediction of the directional index (DI), a quantitative measure of the degree of direction selectivity, was compared with the measured DI obtained from the responses to drifting gratings. The median value of the ratio of the two was 0.30, indicating that there is a significant nonlinear component to direction selectivity. 4. The absolute magnitudes of the responses to gratings moving in both directions of motion were compared with the linear predictions as well. Whereas the preferred direction response showed only a slight amount of facilitation compared with the linear prediction, there was a significant amount of nonlinear suppression in the nonpreferred direction. 5. Spatiotemporal inseparability was demonstrated also with stationary temporally modulated bars. The time course of response to these bars was different for different positions in the receptive field. The degree of spatiotemporal inseparability measured with sinusoidally modulated bars agreed quantitatively with that measured in experiments with stationary gratings. 6. A linear prediction of the responses to drifting luminance borders was compared with the actual responses. As with the grating experiments, the prediction was qualitatively accurate, giving the correct preferred direction but underestimating the magnitude of direction selectivity observed.(ABSTRACT TRUNCATED AT 400 WORDS)

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