scholarly journals An fMRI study of chromatic processing in humans: Temporal characteristics of cortical visual areas

2009 ◽  
Vol 9 (14) ◽  
pp. 38-38
Author(s):  
D. V. D'Souza ◽  
T. Auer ◽  
H. Strasburger ◽  
J. Frahm ◽  
B. B. Lee
Keyword(s):  
Temporal Characteristics ◽  
Fmri Study ◽  
Visual Areas ◽  
Chromatic Processing ◽  
Cortical Visual Areas

scholarly journals Temporal frequency and chromatic processing in humans: An fMRI study of the cortical visual areas

2011 ◽  
Vol 11 (8) ◽  
pp. 8-8 ◽  
Author(s):  
D. V. D'Souza ◽  
T. Auer ◽  
H. Strasburger ◽  
J. Frahm ◽  
B. B. Lee
Keyword(s):  
Temporal Frequency ◽  
Fmri Study ◽  
Visual Areas ◽  
Chromatic Processing ◽  
Cortical Visual Areas

scholarly journals The cortical visual areas of the sheep.

1976 ◽  
Vol 256 (3) ◽  
pp. 497-508 ◽  
Author(s):  
P G Clarke ◽  
D Whitteridge
Keyword(s):  
Visual Areas ◽  
Cortical Visual Areas

scholarly journals Neural correlates of spatial orienting in the human superior colliculus

2011 ◽  
Vol 106 (5) ◽  
pp. 2273-2284 ◽  
Author(s):  
Elaine J. Anderson ◽  
Geraint Rees
Keyword(s):  
Superior Colliculus ◽  
High Speed ◽  
Neural Correlates ◽  
Inhibitory Response ◽  
Neural Basis ◽  
Spatial Orienting ◽  
Visual Areas ◽  
Oculomotor Responses ◽  
Salient Event ◽  
Cortical Visual Areas

A natural visual scene contains more information than the visual system has the capacity to simultaneously process, requiring specific items to be selected for detailed analysis at the expense of others. Such selection and inhibition are fundamental in guiding search behavior, but the neural basis of these mechanisms remains unclear. Abruptly appearing visual items can automatically capture attention, but once attention has been directed away from the salient event, return to that same location is slowed. In non-human primates, signals associated with attentional capture (AC) and subsequent inhibition of return (IOR) have been recorded from the superior colliculus (SC)—a structure known to play a pivotal role in reflexive spatial orienting. Here, we sought to establish whether similar signals could be recorded from the human SC, as well as early retinotopic cortical visual areas, where signals associated with AC and IOR have yet to be investigated with respect to oculomotor responses. Using an optimized oculomotor paradigm together with high-field, high-spatial resolution functional magnetic resonance imaging and high-speed eye tracking, we demonstrate that BOLD signal changes recorded from the human SC correlate strongly with our saccadic measures of AC and IOR. A qualitatively similar pattern of responses was found for V1, but only the inhibitory response associated with IOR persisted through V2 and V3. Although the SC plays a role in mediating these automatic attentional biasing signals, the source of these signals is likely to lie in higher cortical areas.

The Role of Temporal Synchrony as a Binding Cue for Visual Persistence in Early Visual Areas: An fMRI Study

2009 ◽  
Vol 102 (6) ◽  
pp. 3461-3468 ◽  
Author(s):  
Yvonne J. Wong ◽  
Adrian J. Aldcroft ◽  
Mary-Ellen Large ◽  
Jody C. Culham ◽  
Tutis Vilis
Keyword(s):  
Visual Memory ◽  
Iconic Memory ◽  
Occipital Cortex ◽  
Independent Manner ◽  
Object Persistence ◽  
Motion Cues ◽  
Temporal Synchrony ◽  
Fmri Study ◽  
Visual Areas

We examined the role of temporal synchrony—the simultaneous appearance of visual features—in the perceptual and neural processes underlying object persistence. When a binding cue (such as color or motion) momentarily exposes an object from a background of similar elements, viewers remain aware of the object for several seconds before it perceptually fades into the background, a phenomenon known as object persistence. We showed that persistence from temporal stimulus synchrony, like that arising from motion and color, is associated with activation in the lateral occipital (LO) area, as measured by functional magnetic resonance imaging. We also compared the distribution of occipital cortex activity related to persistence to that of iconic visual memory. Although activation related to iconic memory was largely confined to LO, activation related to object persistence was present across V1 to LO, peaking in V3 and V4, regardless of the binding cue (temporal synchrony, motion, or color). Although persistence from motion cues was not associated with higher activation in the MT+ motion complex, persistence from color cues was associated with increased activation in V4. Taken together, these results demonstrate that although persistence is a form of visual memory, it relies on neural mechanisms different from those of iconic memory. That is, persistence not only activates LO in a cue-independent manner, it also recruits visual areas that may be necessary to maintain binding between object elements.

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