Influence of spatial frequency on tuning and bias for orientation and direction in the cat's striate cortex

Hammond, Peter; Pomfrett, C.J.D.

doi:10.1016/0042-6989(90)90078-y

Cited by 33 publications

(40 citation statements)

References 18 publications

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“…5 is interesting because its preferred direction reversed when it was tested at a higher spatial frequency. Although reversing preferred directions occurred in less than 5% of the direction-sensitive cells, it is noteworthy because Hammond and Pomfrett (1990) described a similar type of spatial-frequency-dependent direction tuning in a minority of cells in the cat's striate cortex (discussed below). The reversal of preferred direction in this cell can be predicted by the spatialfrequency tuning curves elicited by gratings drifting in the two opposite directions.…”

Section: Resultsmentioning

confidence: 94%

Direction-sensitive X and Y cells within the A laminae of the cat's LGNd

1994

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Drifting sinusoidal gratings, moving bars, and moving spots were employed to study the direction sensitivity of 425 neurons in the A laminae of the cat's LGNd. Thirty-two percent of X-and Y-type LGNd relay cells exhibit significant direction sensitivity when tested with drifting sinusoidal gratings. X and Y cells exhibit the same degree of direction sensitivity. Moving spots and bars elicit direction specific responses fromLGNd cells that are consistent with those elicited when drifting sinusoidal gratings are employed. For cells that are both orientation and direction sensitive, the preferred direction tends to be orthogonal to the preferred orientation. In general, direction sensitivity is strongest at relatively low spatial frequencies, well below the spatial-frequency cutoff for the cell. The presence of significant numbers of direction-sensitiveLGNd cells raises the possibility that subcortical direction specificity is important for the generation of this property in the visual cortex.

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Section: Resultsmentioning

confidence: 94%

Direction-sensitive X and Y cells within the A laminae of the cat's LGNd

1994

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“…The approximate character of this feature may be traced to the lack of uniformity in orientation preference (oblique effect) and the degree to which individual neurons exhibit separability in SF and . This separability has been a disputed issue (30-32) with evidence on both sides (24,33,34). Recordings in a recent study by Mazer et al (35) from awake behaving monkeys point toward separability, but Ringach et al (36) arrive at a different conclusion.…”

Section: Resultsmentioning

confidence: 99%

The organization of orientation and spatial frequency in primary visual cortex

Sirovich

Uglesich²

2004

Proc. Natl. Acad. Sci. U.S.A.

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Many studies have demonstrated that the primary visual cortex contains multiple functional maps of visual properties (e.g., ocular dominance, orientation preference, and spatial-frequency preference), but as yet no consistent picture has emerged as to how these maps are related to one another. Three divergent, prior opticalimaging studies of spatial frequency are reanalyzed and critiqued in this article. Evidence is presented that a nonstimulus-specific response biased the interpretation of results in previous studies. In addition to reexamining four prior cat experiments, we carried out one new experiment. Through the use of different methods and a careful removal of the nonspecific response, we are led in all instances to a unique view of cortical organization for spatialfrequency preference. In particular, we find little apparent evidence for a columnar organization for spatial frequency. The response recorded by each image pixel may be viewed as arising from an admixture of low-and high-spatial-frequency populations. For most pixels, the ratio of these populations is 1:1.optical imaging ͉ nonspecific response ͉ generalized indicator ͉ function analysis T he retinotopic map relates an element of visual space to an element of cortical tissue. Neurons in the primary visual cortex are known to be differentially sensitive to orientation, , and spatial frequency (SF), k, of corresponding image elements that appear in visual space. ‡ Thus, it may be said that the primary visual cortex maps visual space through a local Fourier analysis (1, 2). The process by which this mapping takes place, although not fully understood, is known to involve information processing by the retina, lateral geniculate nucleus (LGN), and primary visual cortex area V1 (V1) and feedback from higher areas.Casting aside the nature of neuronal circuitry, the functional layout of the primary visual cortex is well established for orientation preference and ocular dominance. Anatomical (3-5) and optical-imaging (6-9) studies have elaborated and extended the columnar view of V1 that emerged from electrophysiology (10, 11). Less can be said of the representation of SF. Extensive electrophysiological recordings (12-17) and optical-imaging experiments have not provided a consistent picture of SF layout. The situation can be further complicated if variations in the temporal properties of the stimuli are included (18).One series of optical-imaging studies (7,(19)(20)(21)(22) advanced the viewpoint that the orientation layout of V1 is organized into high-and low-SF preference columns. From this view, it follows that only a single map is needed to characterize SF. This map contains regions corresponding to high and low SF with opposite signs. Thus high-and low-SF stimuli result in responses of opposite signatures. An obvious shortcoming is that intermediate SF would lead to null or near-null results. On the other hand, Everson et al. (23) reported that SF preference is continuously distributed and that at least two maps are required to depict SF represen...

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“…However, this conflict remains unresolved in the experimental literature. Some studies report a lack of separability (24,25), whereas others support separability (26).…”

Section: Discussionmentioning

confidence: 99%

Spatial frequency and orientation tuning dynamics in area V1

Mazer

Vinje²,

McDermott³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

263

246

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Spatial frequency (SF) and orientation tuning are intrinsic properties of neurons in primary visual cortex (area V1). To investigate the neural mechanisms mediating selectivity in the awake animal, we measured the temporal dynamics of SF and orientation tuning. We adapted a high-speed reverse-correlation method previously used to characterize orientation tuning dynamics in anesthetized animals to estimate efficiently the complete spatiotemporal receptive fields in area V1 of behaving macaques. We found that SF and orientation tuning are largely separable over time in single neurons. However, spatiotemporal receptive fields also contain a small nonseparable component that reflects a significant difference in response latency for low and high SF stimuli. The observed relationship between stimulus SF and latency represents a dynamic shift in SF tuning, and suggests that single V1 neurons might receive convergent input from the magno-and parvocellular processing streams. Although previous studies with anesthetized animals suggested that orientation tuning could change dramatically over time, we find no substantial evidence of dynamic changes in orientation tuning.reverse correlation ͉ striate cortex S patial frequency (SF) and orientation tuning are two of the most prominent features of neuronal selectivity in primary visual cortex (area V1) (1). The dynamics of SF and orientation tuning and their interactions are of particular interest to neurophysiologists because they can reveal important information about the specific circuits and mechanisms of neuronal selectivity (2). Dynamic tuning properties may also be critical for understanding natural vision, where eye movements can introduce complex temporal stimulus dynamics (3, 4).We simultaneously measured the temporal dynamics of both SF and orientation tuning in single V1 neurons in the awake primate. Conventional methods for estimating selectivity in V1 use stationary or drifting gratings of constant SF and orientation. Stimuli are presented for relatively long periods (0.3-1 s), and responses are quantified by mean firing rate. Often one stimulus parameter is varied at a time (e.g., orientation tuning is measured at the best SF). Although this approach can yield accurate orientation and SF tuning estimates, it fails to capture both stimulus interactions and temporal response dynamics that can be obscured by nonspecific onset transients. In addition, methods based on static stimuli can be time-consuming. Efficient characterization methods are particularly important when working with behaving animals, where time is almost always at a premium.One efficient way to characterize tuning that also captures temporal response dynamics is to estimate spatiotemporal receptive fields (STRFs) by using reverse correlation. The STRF describes the probability that a particular spatial stimulus will elicit a spike at a particular latency. In effect, the STRF provides a linear model of a neuron's spatiotemporal filtering characteristics (5, 6).In the visual system, STRFs are traditi...

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Influence of spatial frequency on tuning and bias for orientation and direction in the cat's striate cortex

Cited by 33 publications

References 18 publications

Direction-sensitive X and Y cells within the A laminae of the cat's LGNd

Direction-sensitive X and Y cells within the A laminae of the cat's LGNd

The organization of orientation and spatial frequency in primary visual cortex

Spatial frequency and orientation tuning dynamics in area V1

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