Encoding and Decoding Target Locations With Waves in the Turtle Visual Cortex

2005 ◽  
Vol 52 (4) ◽  
pp. 566-577 ◽  
Author(s):  
X. Du ◽  
B.K. Ghosh ◽  
P. Ulinski
Keyword(s):  
Visual Cortex ◽  
Target Locations

scholarly journals Saccades to a Remembered Location Elicit Spatially Specific Activation in Human Retinotopic Visual Cortex

2009 ◽  
Vol 21 (2) ◽  
pp. 230-245 ◽  
Author(s):  
Joy J. Geng ◽  
Christian C. Ruff ◽  
Jon Driver
Keyword(s):  
Visual Cortex ◽  
Target Location ◽  
Spatial Working Memory ◽  
Auditory Signal ◽  
Functional Magnetic Resonance ◽  
Retinotopic Mapping ◽  
Lingual Gyrus ◽  
Early Visual Cortex ◽  
Fmri Analysis ◽  
Target Locations

The possible impact upon human visual cortex from saccades to remembered target locations was investigated using functional magnetic resonance imaging (fMRI). A specific location in the upper-right or upper-left visual quadrant served as the saccadic target. After a delay of 2400 msec, an auditory signal indicated whether to execute a saccade to that location (go trial) or to cancel the saccade and remain centrally fixated (no-go). Group fMRI analysis revealed activation specific to the remembered target location for executed saccades, in the contralateral lingual gyrus. No-go trials produced similar, albeit significantly reduced, effects. Individual retinotopic mapping confirmed that on go trials, quadrant-specific activations arose in those parts of ventral V1, V2, and V3 that coded the target location for the saccade, whereas on no-go trials, only the corresponding parts of V2 and V3 were significantly activated. These results indicate that a spatial–motor saccadic task (i.e., making an eye movement to a remembered location) is sufficient to activate retinotopic visual cortex spatially corresponding to the target location, and that this activation is also present (though reduced) when no saccade is executed. We discuss the implications of finding that saccades to remembered locations can affect early visual cortex, not just those structures conventionally associated with eye movements, in relation to recent ideas about attention, spatial working memory, and the notion that recently activated representations can be “refreshed” when needed.

scholarly journals Inhibition of Return Impairs Phosphene Detection

2012 ◽  
Vol 24 (11) ◽  
pp. 2262-2267 ◽  
Author(s):  
Daniel T. Smith ◽  
Keira Ball ◽  
Amanda Ellison
Keyword(s):  
Visual Cortex ◽  
Spatial Attention ◽  
Inhibition Of Return ◽  
Visual Exploration ◽  
Extrastriate Cortex ◽  
Neural Signals ◽  
Extrastriate Visual Cortex ◽  
Visual Areas ◽  
Target Locations ◽  
Site Of Stimulation

Efficient visual exploration requires the ability to select possible target locations via spatial attention and to deselect previously inspected locations via inhibition of return (IOR). Although a great deal is known about the effects of spatial attention on processing in visual cortex, much less is known about the effects of IOR on early visual areas. One possibility is that IOR acts in an opposite way to spatial attention, such that, whereas spatial attention enhances target related neural signals in visual cortex, IOR suppress target-related signals. Using a novel dual-coil TMS protocol, we found that IOR reduced the probability of detecting a TMS-induced phosphene in extrastriate cortex (V5). Specifically, a nonpredictive spatial precue presented 500 or 800 msec before stimulation significantly reduced the probability of detecting a phosphene when the precue appeared contralaterally to the site of stimulation (i.e., ipsilaterally to the potential location of the phosphene), compared with ipsilaterally or centrally presented cues. This result demonstrates that IOR facilitates visual exploration by directly affecting the strength of target-related signals in extrastriate visual cortex. This result is consistent with neurophysiological models of attention, which postulate that IOR modulates perception by biasing competition between sensory representations.

scholarly journals Object-based attentional selection emerges late in visual cortical hierarchy for objects of varying perceptual strengths

2020 ◽  
Author(s):  
Shahd Al-Janabi ◽  
Nofar Strommer ◽  
Shai Gabay ◽  
Adam S. Greenberg
Keyword(s):  
Visual Cortex ◽  
Object Representations ◽  
Object Selection ◽  
Uncued Object ◽  
Object Locations ◽  
Object Based ◽  
Cortical Hierarchy ◽  
Attentional Spreading ◽  
Visual Cortical ◽  
Target Locations

AbstractObject-based attention (OBA) can - in addition to acting upon explicit object representations - act upon occluded and illusory objects. It remains unknown, however, whether or not the selection of such object representations is detectable at the same level within visual cortex. This study examined the level within visual cortex (V1-V3, LOC) at which object-based selection is observed for explicit, occluded and illusory objects. During fMRI acquisition, participants identified a target preceded by a predictive arrow cue in the double-rectangle cueing paradigm. We independently localized retinotopically-specific regions of cortex corresponding to all possible target locations to examine neural fluctuations at each level of the visual cortical hierarchy. We found, after cue onset, that activity along visual cortex was not greater for representations of cued than of uncued same object locations. In contrast, we found that activity in V3 was enhanced at retinotopic representations that correspond to uncued same than different object locations. These results, together, support attentional spreading. Additionally, when the target appeared at either the cued or uncued locations, we found higher activation in areas representing uncued same object versus cued locations. This effect emerged along the visual cortical hierarchy. Further, when the target appeared on either the cued or uncued object, we found that activation in V3 transiently increased at uncued same than different object locations. This effect was also detectable upstream in LOC. These results index attentional re-orienting between locations/objects. Effects emerged regardless of object type: explicit or completed. Thus, the gating of object information proceeds completion.Significance StatementWe investigated the level within visual cortex (V1-V3, LOC) that object-based selection is observed for explicit objects and those requiring perceptual completion. We showed that activity along visual cortex was similar for representations of locations on a cued object, which may indicate attention spreads evenly to all locations on an object marked as relevant by the cue. We also showed that activity in late visual areas was greater for representations of uncued same than different object locations, which may indicate that attention enhances the cued object. These findings support the attentional spreading account. Object selection may, thus, be instantiated by even engagement of locations within a cued, and/or suppression of locations within an uncued, object - independent of its type.

Author response for "Projections between visual cortex and pulvinar in the rat"

2020 ◽  
Author(s):  
Leo R. Scholl ◽  
Andrzej T. Foik ◽  
David C. Lyon
Keyword(s):  
Visual Cortex ◽  
Author Response

Receptive Fields of Dendritic Potentials from Within the Visual Cortex of the Cat

1965 ◽  
Author(s):  
John A. Satterberg ◽  
Leo Ganz
Keyword(s):  
Visual Cortex ◽  
Receptive Fields

Effects of overexpression of GFP-tagged BDNF on neurons cultured from rat visual cortex

2000 ◽  
Vol 38 ◽  
pp. S139
Author(s):  
M Morishima
Keyword(s):  
Visual Cortex

Effects of visual experience on development of T-type Ca2+ channels in rat visual cortex

2000 ◽  
Vol 38 ◽  
pp. S54
Author(s):  
Y Yoshimura
Keyword(s):  
Visual Cortex ◽  
Visual Experience ◽  
Ca2 Channels

Experience-dependent regulation of synchronized slow-wave sleep in visual cortex

2000 ◽  
Vol 38 ◽  
pp. S171
Author(s):  
H Miyamoto
Keyword(s):  
Visual Cortex ◽  
Slow Wave ◽  
Slow Wave Sleep
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