The dorsal third tier area inGalago senegalensis

Allman, John M.; Campbell, Colin; McGuinness, Evelynn

doi:10.1016/0006-8993(79)90450-5

Cited by 37 publications

(19 citation statements)

References 10 publications

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“…Microelectrode mapping studies of dorsolateral visual cortex in galagos also failed to provide convincing evidence for V3 [Allman and Kaas, 1975;Allman et al, 1979;Rosa et al, 1997]. The results of all three studies revealed neurons in the region of DM with receptive fields in upper visual quadrants, and this is consistent with the proposal that rostral DM represents the upper visual quadrant.…”

Section: The Third Visual Area V3supporting

confidence: 78%

“…Area DM in galagos has been defined as a darkly myelinated oval of cortex adjacent to dorsal V2 that is similar to the width of MT [Allman et al, 1979;Beck and Kaas, 1998b]. Our preparations show DM as a moderately myelinated region about 4 mm wide and about 6 mm long that was separated from the V2 border by a narrower strip of moderately myelinated cortex corresponding to V3d.…”

Section: Architectonic Identification Of Cortical Visual Areasmentioning

confidence: 87%

“…There is evidence that receptive fields for neurons in the dorsal cortex just rostral to V2 (perhaps V3) are larger than those for neurons in V2 and V1 [Allman et al, 1979;Rosa et al, 1997]. Yet, there is no other relevant information from recordings in galagos.…”

Section: The Third Visual Area V3mentioning

confidence: 99%

“…There is also considerable evidence from non-invasive imaging studies that visual cortex in humans is subdivided into a large number of visual areas [see Sereno et al, 1995;Shipp et al, 1995;DeYoe et al, 1996;Tootell et al, 1997]. Less is known about visual cortex organization in prosimian primates, but already there is evidence for at least 5-10 visual areas [Allman et al, 1973[Allman et al, , 1979Symonds and Kaas, 1978;Newsome and Allman, 1980;Cusick and Kaas, 1988a;Kaas, 1990, 1993;Preuss et al, 1993;Rosa et al, 1997;Beck and Kaas, 1998b;Collins et al, 2001]. However, for all of these primate groups only a few visual areas are so well defined that there is widespread agreement about their existence and location.…”

Section: Introductionmentioning

confidence: 99%

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Connectional Evidence for Dorsal and Ventral V3, and Other Extrastriate Areas in the Prosimian Primate, <i>Galago garnetti</i>

Lyon

Kaas²

2002

Brain Behav Evol

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Previously we described patterns of connections that support the concept of V3 in small New World marmoset monkeys, three species of larger New World monkeys, and two species of Old World macaque monkeys. Here we describe a pattern of V1 connections with extrastriate visual cortex in Galago garnetti (also known as Otolemur garnetti) that demonstrates the existence of a V3 in a strepsirhine (prosimian) primate. Injections of fluorochromes or cholera toxin subunit-B (CTB) in V1 labeled cells and terminals in retinotopically matched regions in V2, V3, DL (V4), and MT. Labeled axon terminations were more focused primarily in middle layers of cortex, likely representing ‘feedforward’ input from V1, whereas labeled cells were more widespread and found in both superficial and deeper cortical layers, indicative of feedback projections. Averaged across injections, V3 had the third largest percentage of labeled cells (11%), following only V2 (47%) and the middle temporal area (MT; 19%). The dorsolateral area (DL, or V4; 9%) also contained a relatively large number of retrogradely labeled cells. These results indicate that V2, V3, DL (V4), and MT are retinotopically connected with V1, and provide major sources of feedback. Other extrastriate areas were less densely connected to V1, and there was no clear indication of labeled terminals. Inferotemporal cortex (IT) provided nearly 7% of feedback connections, whereas the dorsomedial area (DM) contributed about 3%. The remaining areas that have been proposed for galago extrastriate cortex, MTc, MST, FST, LPP and VPP, each accounted for about 1% or less of the total number of labeled cells. Thus, six extrastriate areas, V2, MT, V3, DL (V4), IT, and DM provide over 96% of visual cortex projections to V1. These areas also provide most of the projections to V1 in New and Old World monkeys.

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Section: The Third Visual Area V3supporting

confidence: 78%

Section: Architectonic Identification Of Cortical Visual Areasmentioning

confidence: 87%

Section: The Third Visual Area V3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Connectional Evidence for Dorsal and Ventral V3, and Other Extrastriate Areas in the Prosimian Primate, <i>Galago garnetti</i>

Lyon

Kaas²

2002

Brain Behav Evol

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“…In addition, if the slower moving dots become hidden when they approach the faster moving cluster, then the powerful depth cue of interposition can make the faster moving cluster appear in depth in front of the slower moving background. Recently, Allman, Campbell, and McGuinness (1979) and Frost, Morgan, and Nakayama (1982) have confirmed this finding. Thus, motion, occlusion, and motion sheering off edges can produce strong effects of area segregation in depth.…”

Section: Fucker and Depthsupporting

confidence: 70%

Flicker induces depth: Spatial and temporal factors in the perceptual segregation of flickering and nonflickering regions in depth

Wong

Weisstein

1984

Perception & Psychophysics

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If some regions of a random-dotfieldare flickered, then the nonflickering areas appear to stand out in depth in front of the flickering regions. This perception of depth is optimal within a limited range of temporal frequencies. The average temporal luminance of the flickering and nonflickering regions was kept equal, so the depth segregation is not due to a luminance difference. In fact, depth is seen even when the average temporal luminance of the flickering regions is twice that of the steadily presented regions. The magnitude of perceiveddepth is affected by the percentage of luminance modulation: depth is maximal at 100% modulation and diminishes as the percent modulation decreases. We charted the tuning function using alternating flickering and nonflickering random-dot bars and found it to be similar to those of visual channels most sensitive to high temporal frequency.If areas of a filled visual field are flickered, the fMckering regions appear to lie in depth well behind the nonflickering regions (Wong & Weisstein, 1983a). When parts of a random-dot field were flickered so that the display consisted of alternating flickering and non flickering "bars" composed of dots, the nonflickering "bars" were seen to stand out in front of the flickering "bars."The nonflickering "bars" appear to form coherent rectangular shapes located in front of a background of flickering dots. The impression is not different from that of a row of figures contrasted against a flickering backdrop. The perceived depth effect reminds one of random-dot stereograms in which an area of dots may appear to float out in space in front of a background. Figure 1 is a representation of what the percept looks like to an observer. The flickering areas appear to stay at a constant depth behind the nonflickering areas rather than receding and approaching with the on-and-off cycle of the flicker. In other words, once the area is flickered at the appropriate temporal frequency, the flickering area remains steadily at a constant depth behind the nonflickering areas.The depth segregation produced by flicker-flickerinduced depth-is not due to a luminance difference between the flickering and nonflickering areas, since the average temporal luminance of all the regions was kept equal. It is also not dependent on the textural elements making up the visual field, since we obtained the effect with dots, horizontal lines, and vertical lines; nor does it depend on a specific configuration of the flickering and nonflickering regions, since we obtained this effect with "bars" made up of different textures and with concentric squares. The effect is not dependent on the density of dots filling the flickering and nonflickering regions, provided there is an adequate number of dots to define a region. Moreover, we found that a temporal frequency of about 6 Hz produced the greatest depth separation between the flickering and nonflickering areas, suggesting that visual channels responding pri-229

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The Evolution of Visual Cortex in Primates

Kaas

2005

The Primate Visual System

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The dorsal third tier area inGalago senegalensis

Cited by 37 publications

References 10 publications

Connectional Evidence for Dorsal and Ventral V3, and Other Extrastriate Areas in the Prosimian Primate, <i>Galago garnetti</i>

Connectional Evidence for Dorsal and Ventral V3, and Other Extrastriate Areas in the Prosimian Primate, <i>Galago garnetti</i>

Flicker induces depth: Spatial and temporal factors in the perceptual segregation of flickering and nonflickering regions in depth

The Evolution of Visual Cortex in Primates

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