Using Functional Magnetic Resonance Imaging to Assess Adaptation and Size Invariance of Shape Processing by Humans and Monkeys

Sawamura, Hiromasa; Georgieva, Svetlana; Vogels, Rufin; Vanduffel, Wim; Orban, Guy A.

doi:10.1523/jneurosci.0377-05.2005

Cited by 143 publications

(140 citation statements)

References 69 publications

(124 reference statements)

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“…The correspondence between fMRI activation patterns in monkeys and humans in previous studies (e.g., [53][54][55][56][57][58] and, partly, in our work is encouraging, although it does not necessarily imply that the underlying behavioral strategies and neuronal activity in the two species are the same. Nevertheless, monkey fMRI provides a crucial control for the common interpretation of human imaging and monkey electrophysiology data.…”

Section: Discussionsupporting

confidence: 73%

Space representation for eye movements is more contralateral in monkeys than in humans

Kagan

Iyer

Lindner

et al. 2010

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

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Contralateral hemispheric representation of sensory inputs (the right visual hemifield in the left hemisphere and vice versa) is a fundamental feature of primate sensorimotor organization, in particular the visuomotor system. However, many higher-order cognitive functions in humans show an asymmetric hemispheric lateralizatione.g., right brain specialization for spatial processing-necessitating a convergence of information from both hemifields. Electrophysiological studies in monkeys and functional imaging in humans have investigated space and action representations at different stages of visuospatial processing, but the transition from contralateral to unified global spatial encoding and the relationship between these encoding schemes and functional lateralization are not fully understood. Moreover, the integration of data across monkeys and humans and elucidation of interspecies homologies is hindered, because divergent findings may reflect actual species differences or arise from discrepancies in techniques and measured signals (electrophysiology vs. imaging). Here, we directly compared spatial cue and memory representations for action planning in monkeys and humans using event-related functional MRI during a working-memory oculomotor task. In monkeys, cue and memory-delay period activity in the frontal, parietal, and temporal regions was strongly contralateral. In putative human functional homologs, the contralaterality was significantly weaker, and the asymmetry between the hemispheres was stronger. These results suggest an inverse relationship between contralaterality and lateralization and elucidate similarities and differences in human and macaque cortical circuits subserving spatial awareness and oculomotor goal-directed actions.BOLD signal | event-related functional MRI | brain evolution | delayed saccades | lateralization

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Section: Discussionsupporting

confidence: 73%

Space representation for eye movements is more contralateral in monkeys than in humans

Kagan

Iyer

Lindner

et al. 2010

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

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“…When subjects were performing the high-acuity task (Vanduffel et al, 2001), the target was replaced with a yellow bar whose size was adapted for each subject based on psychophysical testing in the scanner (Sawamura et al, 2005). To reduce the amount of head motion during the scanning sessions, the subjects were asked to bite an individually molded bite bar fixed on the scanner table.…”

Section: Participantsmentioning

confidence: 99%

“…Six of these subjects (1, 3, 19, 20, 21, 22 in Table 1) were scanned while performing a high-acuity task (Vanduffel et al, 2001) during which the stimuli used in the main experiment were presented. They were required to interrupt a light beam with their right thumb when a small yellow bar, presented in the middle of the screen changed orientation (for 1 s) from horizontal to vertical at random intervals between 2 and 10 s. Psychophysical tests performed in the scanner indicated that performance level (percentage correct detection of orientation change) decreased and reaction time increased with decreasing bar size, suggesting that these are sensitive indicators of the subjects' attentional state (Sawamura et al, 2005). Before the scanning session subjects performed a psychophysical test in the scanner in which the level of performance at different bar sizes was tested.…”

Section: Control Experiment: High-acuity Task (N ϭ 6)mentioning

confidence: 99%

The Processing of Three-Dimensional Shape from Disparity in the Human Brain

Georgieva¹,

Peeters²,

Kolster³

et al. 2009

J. Neurosci.

191

233

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Three-dimensional (3D) shape is important for the visual control of grasping and manipulation and for object recognition. Although there has been some progress in our understanding of how 3D shape is extracted from motion and other monocular cues, little is known of how the human brain extracts 3D shape from disparity, commonly regarded as the strongest depth cue. Previous fMRI studies in the awake monkey have established that the interaction between stereo (present or absent) and the order of disparity (

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“…To control for possible differences in attention during presentation of the action and control stimuli, we performed a control experiment in which monkey M5 performed an acuity task ( Vanduffel et al, 2001;Sawamura et al, 2005), whereas the action stimuli were presented in the background. The orientation of the bar changed to vertical at random moments, which the monkey had to indicate by a manual response.…”

Section: Additional Functional Characteristics Of Less Known or Unknomentioning

confidence: 99%

Charting the Lower Superior Temporal Region, a New Motion-Sensitive Region in Monkey Superior Temporal Sulcus

Nelissen¹,

Vanduffel²,

Orban³

2006

J. Neurosci.

155

164

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Although the role of the middle temporal (MT/V5) area and its medial superior temporal (MST) satellites in motion processing has been well explored, relatively little is known about motion regions located more rostrally in the superior temporal sulcus (STS), such as the fundus of the superior temporal (FST) area, the superior temporal polysensory (STP) region, or beyond. To fill this void, we used contrast-enhanced functional magnetic resonance imaging in awake macaques and a five-step testing procedure that allowed us to identify six motion-sensitive regions within the STS. Direction adaptation tests confirmed the motion sensitivity of these six regions. Five of them [MT/V5, its three satellites, and the middle part of the STP (STPm) region in the upper bank of the STS] have been documented by previous single-cell studies. A sixth, previously unknown motion-responsive region, which we termed the lower superior temporal (LST) region, was observed on the lower bank and fundus of the STS, 6 -8 mm anterior to the FST area. In contrast to the MST areas, the LST region responds to slow as well as fast speeds and is responsive to static and moving images of objects, to patterns defined by opponent motion, and to actions. These results, obtained in both group and single-subject analyses, suggest that motion information in the STS might follow a second path, in addition to the MT/V5-MST path. This ventral path including the LST region, FST area, and STPm region is likely involved in the visual analysis of actions and biological motion.

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Using Functional Magnetic Resonance Imaging to Assess Adaptation and Size Invariance of Shape Processing by Humans and Monkeys

Cited by 143 publications

References 69 publications

Space representation for eye movements is more contralateral in monkeys than in humans

Space representation for eye movements is more contralateral in monkeys than in humans

The Processing of Three-Dimensional Shape from Disparity in the Human Brain

Charting the Lower Superior Temporal Region, a New Motion-Sensitive Region in Monkey Superior Temporal Sulcus

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