scholarly journals Dynamics of Tuning in the Fourier Domain

2008 ◽  
Vol 100 (1) ◽  
pp. 239-248 ◽  
Author(s):  
Brian J. Malone ◽  
Dario L. Ringach
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex ◽  
Fourier Domain ◽  
Cortex Area ◽  
New Findings ◽  
Cortical Responses ◽  
Low Pass ◽  
The Subject ◽  
The Relationship

Neurons in primary visual cortex (area V1) are jointly tuned to the orientation and spatial frequency of sinusoidal stimuli (the Fourier domain). The role that suppressive mechanisms play in shaping the tuning and dynamics of cortical responses remains the subject of debate. Here we used subspace reverse correlation to study the relationship between suppression by nonoptimal stimuli, the spectral-temporal separability of the responses, and their persistence in time. Two clear relationships emerged from our data. First, cells with inseparable responses were often accompanied by suppression to nonpreferred stimuli, while separable responses showed mostly enhancement by their preferred stimuli. Second, inseparable responses were characterized by a longer persistence in time compared with those with separable dynamics. A parametric model that assumes the additive combination of separable enhancement and suppression signals, with suppression constrained to be low-pass in spatial frequency and untuned for orientation, explained the data well. These new findings, in addition to an established correlation between selectivity and suppression for nonoptimal stimuli, clarify how the dynamics and selectivity of cortical responses are shaped by suppressive signals and how their interplay generates the large diversity of responses observed in primary visual cortex.

scholarly journals Temporo-nasally biased moving grating selectivity in mouse primary visual cortex

2019 ◽  
Author(s):  
Marie Tolkiehn ◽  
Simon R. Schultz
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex ◽  
Moving Objects ◽  
Direction Selectivity ◽  
Orientation Tuning ◽  
High Signal ◽  
Forward Movement ◽  
Upward Moving

AbstractOrientation tuning in mouse primary visual cortex (V1) has long been reported to have a random or “salt-and-pepper” organisation, lacking the structure found in cats and primates. Laminar in-vivo multi-electrode array recordings here reveal previously elusive structure in the representation of visual patterns in the mouse visual cortex, with temporo-nasally drifting gratings eliciting consistently highest neuronal responses across cortical layers and columns, whilst upward moving gratings reliably evoked the lowest activities. We suggest this bias in direction selectivity to be behaviourally relevant as objects moving into the visual field from the side or behind may pose a predatory threat to the mouse whereas upward moving objects do not. We found furthermore that direction preference and selectivity was affected by stimulus spatial frequency, and that spatial and directional tuning curves showed high signal correlations decreasing with distance between recording sites. In addition, we show that despite this bias in direction selectivity, it is possible to decode stimulus identity and that spatiotemporal features achieve higher accuracy in the decoding task whereas spike count or population counts are sufficient to decode spatial frequencies implying different encoding strategies.Significance statementWe show that temporo-nasally drifting gratings (i.e. opposite the normal visual flow during forward movement) reliably elicit the highest neural activity in mouse primary visual cortex, whereas upward moving gratings reliably evoke the lowest responses. This encoding may be highly behaviourally relevant, as objects approaching from the periphery may pose a threat (e.g. predators), whereas upward moving objects do not. This is a result at odds with the belief that mouse primary visual cortex is randomly organised. Further to this biased representation, we show that direction tuning depends on the underlying spatial frequency and that tuning preference is spatially correlated both across layers and columns and decreases with cortical distance, providing evidence for structural organisation in mouse primary visual cortex.

scholarly journals Subdomains within orientation columns of primary visual cortex

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw0807 ◽  
Author(s):  
Ming Li ◽  
Xue Mei Song ◽  
Tao Xu ◽  
Dewen Hu ◽  
Anna Wang Roe ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Accurate Method ◽  
Electrode Position ◽  
Tree Shrews ◽  
Form Processing ◽  
Orientation Columns ◽  
Relationship Of ◽  
First Time ◽  
The Relationship

In the mammalian visual system, early stages of visual form processing begin with orientation-selective neurons in primary visual cortex (V1). In many species (including humans, monkeys, tree shrews, cats, and ferrets), these neurons are organized in a beautifully arrayed pinwheel-like orientation columns, which shift in orientation preference across V1. However, to date, the relationship of orientation architecture to the encoding of multiple elemental aspects of visual contours is still unknown. Here, using a novel, highly accurate method of targeting electrode position, we report for the first time the presence of three subdomains within single orientation domains. We suggest that these zones subserve computation of distinct aspects of visual contours and propose a novel tripartite pinwheel-centered view of an orientation hypercolumn.

Man's Triune Conscious Mind: Part III

1995 ◽  
Vol 81 (2) ◽  
pp. 463-466
Author(s):  
Carl G. Aurell
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Conscious Mind ◽  
Perceptual Model ◽  
Cortex Area ◽  
Layer 4

The perceptual model, discussed previously in Part II, is applied to the organization of the visual cortex in a search for “consciousness neurons,” i.e., sources of sensations, images, and percepts. It is hypothesized that these three conscious phenomena emerge in the primary visual cortex, Area VI, possibly from neurons in its Layer 4.

scholarly journals Orthogonal micro-organization of orientation and spatial frequency in primate primary visual cortex

2012 ◽  
Vol 15 (12) ◽  
pp. 1683-1690 ◽  
Author(s):  
Ian Nauhaus ◽  
Kristina J Nielsen ◽  
Anita A Disney ◽  
Edward M Callaway
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex

Analysis of Direction Selectivity Arising from Recurrent Cortical Interactions

1998 ◽  
Vol 10 (2) ◽  
pp. 353-371 ◽  
Author(s):  
Paul Mineiro ◽  
David Zipser
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Detailed Comparison ◽  
Direction Selectivity ◽  
Dynamical Model ◽  
Physiological Data ◽  
Model Based ◽  
The Subject ◽  
Neuroscience Community

The relative contributions of feedforward and recurrent connectivity to the direction-selective responses of cells in layer IVB of primary visual cortex are currently the subject of debate in the neuroscience community. Recently, biophysically detailed simulations have shown that realistic direction-selective responses can be achieved via recurrent cortical interactions between cells with nondirection-selective feedforward input (Suarez et al., 1995; Maex & Orban, 1996). Unfortunately these models, while desirable for detailed comparison with biology, are complex and thus difficult to analyze mathematically. In this article, a relatively simple cortical dynamical model is used to analyze the emergence of direction-selective responses via recurrent interactions. A comparison between a model based on our analysis and physiological data is presented. The approach also allows analysis of the recurrently propagated signal, revealing the predictive nature of the implementation.

Spatial Overlap of on and off Subregions and Its Relation to Response Modulation Ratio in Macaque Primary Visual Cortex

2005 ◽  
Vol 93 (2) ◽  
pp. 919-928 ◽  
Author(s):  
Mario L. Mata ◽  
Dario L. Ringach
Keyword(s):  
Visual Cortex ◽  
Simple Model ◽  
Primary Visual Cortex ◽  
Response Modulation ◽  
Noise Pattern ◽  
Unimodal Distribution ◽  
Spatial Overlap ◽  
The Relationship ◽  
Spatial Maps ◽  
Modulation Ratio

We studied the spatial overlap of on and off subregions in macaque primary visual cortex and its relation to the response modulation ratio (the F1/ F0 ratio). Spatial maps of on and off subregions were obtained by reverse correlation with a dynamic noise pattern of bright and dark spots. Two spatial maps, on and off, were produced by cross-correlating the spike train with the location of bright and dark spots in the stimulus respectively. Several measures were used to assess the degree of overlap between subregions. In a subset of neurons, we also computed the F1/ F0 ratio in response to drifting sinusoidal gratings. Significant correlations were found among all the overlap measures and the F1/ F0 ratio. Most overlap indices considered, and the F1/ F0 measure, had bimodal distributions. In contrast, the distance between on and off subregions normalized by their size was unimodal. Surprisingly, a simple model that additively combines on and off subregions with spatial separations drawn from a unimodal distribution, can readily explain the data. These analyses clarify the relationship between subregion overlap and the F1/ F0 ratio in macaque primary visual cortex, and a simple model provides a parsimonious explanation for the co-existence of bimodal distributions of overlap indices and a unimodal distribution of the normalized distance.

scholarly journals Erratum: Corrigendum: Orthogonal micro-organization of orientation and spatial frequency in primate primary visual cortex

2013 ◽  
Vol 16 (12) ◽  
pp. 1907-1907
Author(s):  
Ian Nauhaus ◽  
Kristina J Nielsen ◽  
Anita A Disney ◽  
Edward M Callaway
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Primary Visual Cortex
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