Convergence of magno- and parvocellular pathways in layer 4B of macaque primary visual cortex

Sawatari, Atomu; Callaway, Edward M.

doi:10.1038/380442a0

Cited by 133 publications

(89 citation statements)

References 14 publications

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“…The interpretation, in neurobiological terms, ofmanipulations such as those carried out in this report are acknowledged to be controversial, owing to the extensive cross-talk between the M and P systems (Cavanagh, 1996;Sawatari & Callaway, 1996). Yetthere are a number of instances in which such manipulation provides results that are consistent with other lines ofevidence in suggesting a predominant, ifnot exclusive, role for one or other pathway (Livingstone & Hubel, 1987;Lovegrove et al, 1991;B.…”

Section: Discussionsupporting

confidence: 77%

Do the magnocellular and parvocellular visual pathways contribute differentially to subitizing and counting?

Simon

Peterson

Patel

et al. 1998

Perception & Psychophysics

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We investigated the neurobiological basis of visual processes involved in object enumeration. Subitizing, the ability to rapidly and accurately enumerate four or fewer objects, is thought to depend on preattentive processing of visual stimuli, whereas counting of more numerous objects is thought to require serial shifts of attention. Weattempted to distinguish between the hypothesis that the magnocellular (M) visual pathway is the preferential route for subitizing, and the alternative hypothesis that there is no selectivity for the Mpathway or its counterpart, the parvocellular (P) visual pathway, in visual object enumeration. Green rectangles were presented on an equiluminant red background to impair M pathway processing. This slowed enumeration performance relative to a control condition in which object/background luminance differed, especially when the rectangles were relatively large and widely spaced and had constant retinal eccentricity. When low luminance contrast was used to impair processing along the P pathway, enumeration performance was slowed relative to a high-contrast control condition, especially when the rectangles were small and closely spaced. Overall, our manipulations affected enumeration performance without selectivity for subitizing or counting ranges and without altering the slope of the functions relating reaction time to numerosity. Thus, our results favor the hypothesis that visual enumeration does not depend preferentially on either the M or the P pathway.

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Section: Discussionsupporting

confidence: 77%

Do the magnocellular and parvocellular visual pathways contribute differentially to subitizing and counting?

Simon

Peterson

Patel

et al. 1998

Perception & Psychophysics

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show abstract

“…Magnocellular dysfunction can affect ventral stream FFA processing via several routes. Magnocellular and parvocellular pathways interact beginning in V1 with extensive interactions thereafter (Sawatari and Callaway, 1996;Vidyasagar et al, 2002). Thus, magnocellular dysfunction can affect ventral stream processing by impaired interactions between pathways at the level of V1 or V2 leading to impaired direct input to FFA, or by aberrant cross-over input from dorsal stream areas, such as the middle temporal visual area, to FFA (e.g., the frame and fill hypothesis) (Bar, 2003;Schroeder et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

What's in a face? Effects of stimulus duration and inversion on face processing in schizophrenia

Butler

Tambini

Yovel

et al. 2008

Schizophrenia Research

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A number of studies show deficits in early-stage visual processing in schizophrenia. Deficits are also seen at more complex levels, such as ability to discriminate faces. This study investigated the "face inversion" effect, which reflects intrinsic cortical processing within the ventral visual stream, as well as contrast sensitivity, which reflects low-level visual processing, in order to evaluate integrity of specific stages of face processing in schizophrenia. Patients with schizophrenia and controls discriminated between pairs of upright or inverted faces or houses that had been manipulated to differ in the shape of the parts or the spatial distance among parts. The duration threshold for above chance performance on upright stimuli was obtained for patients using a house discrimination task. Contrast sensitivity was assessed for gratings of three spatial frequencies ranging from 0.5 to 21 cycles/degree. Patients needed significantly longer time to obtain 70% correct for upright stimuli and showed decreased contrast sensitivity. Increased duration threshold correlated with reduced contrast sensitivity to low (magnocellular-biased) but not medium or high spatial frequency stimuli. Using increased durations, patients showed significant inversion effects that were equivalent to those of controls on the face part and spacing tasks. Like controls, patients did not show inversion effects on the house tasks. These findings show that patients have difficulty integrating visual information as shown by increased duration thresholds. However, when faces were presented at these longer duration thresholds, patients showed the same relative processing ability for upright vs. inverted faces as controls, suggesting preserved intrinsic processing within cortical face processing regions. Similar inversion effects for face part and spacing for both groups suggest that they are using the same holistic face processing mechanism.

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“…Because there is no need to compare color signals for motion estimation, these computations can be performed using a color-univariant spatiotemporal signal; that is, a signal that combines luminance and chromatic inputs (Adelson and Bergen, 1985;Dougherty et al, 1999). Such a signal might be implemented by combining the magnocellular pathway (large weight) with parvocellular and koniocellular pathways (small weights) (Maunsell et al, 1990;Sawatari and Callaway, 1996;Wandell et al, 1999). Second, motion computations perform best when the spatiotemporal signal has precise temporal information.…”

Section: Mt؉/v3a Networkmentioning

confidence: 99%

Specializations for Chromatic and Temporal Signals in Human Visual Cortex

Liu¹,

Wandell²

2005

J. Neurosci.

110

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Neurological case studies and qualitative measurements suggest that regions within human extrastriate cortex are specialized for different perceptual functions, including color. However, there are few quantitative measurements of human extrastriate color specializations. We studied the chromatic and temporal responses in several different clusters of human visual field maps using functional magnetic resonance imaging. Contrast response functions were measured for luminance [(L ϩ M)-cone], red-green [(L Ϫ M)-cone] and blueyellow (S-cone) modulations at various temporal frequencies. In primary visual cortex (V1), temporal responsivities to luminance and red-green modulations are approximately constant up to 10 Hz, but responsivities to blue-yellow modulations decrease significantly. In ventral occipital cortex (VO), all colors elicit strong responses, and, for each color, low temporal frequency modulations are more effective than high temporal frequency modulations. Hence, VO represents the full range of color information but does not respond well to rapid modulations. Conversely, in human motion-selective cortex (MTϩ) and V3A, blue-yellow modulations elicit very weak responses, whereas luminance and red-green high temporal frequency modulations are equally or more effective than low temporal frequency modulations. Hence, these dorsal occipital regions respond well to rapid modulations, but not all color information is represented. Similar to human motion perception, MTϩ and V3A respond powerfully to all temporal frequencies but only to some colors. Similar to human color perception, VO responds powerfully to all colors but only to relatively low temporal frequencies.

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Convergence of magno- and parvocellular pathways in layer 4B of macaque primary visual cortex

Cited by 133 publications

References 14 publications

Do the magnocellular and parvocellular visual pathways contribute differentially to subitizing and counting?

Do the magnocellular and parvocellular visual pathways contribute differentially to subitizing and counting?

What's in a face? Effects of stimulus duration and inversion on face processing in schizophrenia

Specializations for Chromatic and Temporal Signals in Human Visual Cortex

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