The middle temporal visual area (MT) in the bushbaby,Galago senegalensis

Allman, John M.; Kaas, Jon H.; Lane, R.H.

doi:10.1016/0006-8993(73)90576-3

Cited by 114 publications

(79 citation statements)

References 10 publications

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“…1D). Defined by imaging, the size of MT (18 mm 2 with a rostrocaudal length of 4.1 mm and a dorsoventral height of 6.3 mm) corresponds with previous portrayals of MT in bush babies (11,12) and with the size of MT judged from histological boundaries in the present cases (Fig. 1D).…”

Section: Resultssupporting

confidence: 86%

“…In contrast, the red band corresponds to the zero horizontal activation zone, effectively dividing MT into dorsal and ventral halves. The Ϫ8°horizontal window shifted the band of activation (blue) into the dorsal half of MT, as predicted by microelectrode studies of retinotopy (11). However, the retinotopy revealed by optical imaging was crude, with restricted stimuli activating large portions of MT and spatially adjacent stimuli activating largely overlapping regions.…”

Section: Resultsmentioning

confidence: 66%

“…3A), whereas a narrow (4°) vertical window centered on the vertical meridian through the center of the gaze activated a broad strip of MT along its outer border (Fig. 3B), where the vertical meridian is represented (11,13). The vertical meridian stimulus also activated regions well into MT, indicating that the responsive neurons are not tightly confined to the MT border.…”

Section: Resultsmentioning

confidence: 93%

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Optical imaging of visually evoked responses in prosimian primates reveals conserved features of the middle temporal visual area

Collins

Kaskan

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Optical imaging of intrinsic cortical responses to visual stimuli was used to characterize the organization of the middle temporal visual area (MT) of a prosimian primate, the bush baby (Otolemur garnetti). Stimulation with moving gratings revealed a patchwork of oval-like domains in MT. These orientation domains could, in turn, be subdivided into zones selective to directional movements that were mainly orthogonal to the preferred orientation. Similar, but not identical, zones were activated by movements of random dots in the preferred direction. Orientation domains shifted in preference systematically either around a center to form pinwheels or as gradual linear shifts. Stimuli presented in different portions of the visual field demonstrated a global representation of visual space in MT. As optical imaging has revealed similar features in MT of New World monkeys, MT appears to have retained these basic features of organization for at least the 60 million years since the divergence of prosimian and simian primates.

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 93%

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Optical imaging of visually evoked responses in prosimian primates reveals conserved features of the middle temporal visual area

Collins

Kaskan

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…Single unit studies reported a consistent retinotopic organization in area MT in several primate species (Allman et al, 1973;Van Essen et al, 1981); however, it has been difficult to reveal retinotopy in human MTϩ. Instead, fMRI studies distinguished between presumptive areas MT versus MST in human MTϩ, on the basis of properties related to the classical contralateral retinotopy (Huk et al, 2002).…”

Section: Candidate Retinotopic Areasmentioning

confidence: 99%

“…For example, the obvious laminar differences in myelination in V1 are now imaged almost routinely (Barbier et al, 2002). On the basis of histological studies, myelin-sensitive imaging could eventually distinguish subtler differences in areas V2 (Tootell et al, 1983;Rosa and Krubitzer, 1999), V3 (Burkhalter et al, 1986), V3A (Lewis and Van Essen, 2000), MT (Allman et al, 1973;Van Essen et al, 1981;Tootell et al, 1985), and LIP/VIP (Blatt et al, 1990) and specific parietal areas (Lewis and Van Essen, 2000). Sophisticated analysis of MR images can also reveal quantitative differences in cortical thickness (Fischl et al, 2002); some areas (e.g., V1) are thinner than surrounding areas.…”

Section: Mri Mapping Of Histological Differencesmentioning

confidence: 99%

Neuroimaging Weighs In: Humans Meet Macaques in “Primate” Visual Cortex

2003

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Visuotopic organisation and neuronal response selectivity for direction of motion in visual areas of the caudal temporal lobe of the marmoset monkey (Callithrix jacchus): Middle temporal area, middle temporal crescent, and surrounding cortex

1998

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On the basis of extracellular recordings in marmoset monkeys, we report on the organisation of the middle temporal area (MT) and the surrounding middle temporal crescent (MTc). Area MT is approximately 5-mm long and 2-mm wide, whereas the MTc forms a crescent-shaped band of cortex 1-mm wide. Neurones in area MT form a first-order representation of the contralateral hemifield, whereas those in the MTc form a second-order representation with a field discontinuity near the horizontal meridian. The representation of the vertical meridian forms the border between area MT and the MTc. In both areas, the fovea is represented ventrocaudally, and the visual field periphery is represented dorsorostrally. Analysis of single units revealed that 86% of cells in area MT show a strong selectivity for the direction of motion of visual stimuli. The proportion of direction-selective cells in the MTc (53%), whereas lower than that in area MT, is much higher than that observed in most other visual areas. Neurones in the cortex immediately rostral to area MT and the MTc are direction selective, with receptive fields predominantly located in the visual field periphery. In contrast, only a minority of the cells in the cortex ventral to the MTc are direction selective, and their receptive fields emphasise central vision. The results suggest that the MTc is functionally closely related to area MT, and distinct from the areas forming the dorsolateral complex. The MTc may have a role in combining information about motion in the visual field, processed by area MT, with information about stimulus shape, processed by the dorsolateral complex.

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The middle temporal visual area (MT) in the bushbaby,Galago senegalensis

Cited by 114 publications

References 10 publications

Optical imaging of visually evoked responses in prosimian primates reveals conserved features of the middle temporal visual area

Optical imaging of visually evoked responses in prosimian primates reveals conserved features of the middle temporal visual area

Neuroimaging Weighs In: Humans Meet Macaques in “Primate” Visual Cortex

Visuotopic organisation and neuronal response selectivity for direction of motion in visual areas of the caudal temporal lobe of the marmoset monkey (Callithrix jacchus): Middle temporal area, middle temporal crescent, and surrounding cortex

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