FMRI evidence for a 'parietal reach region' in the human brain

Connolly, Jason D.; Andersen, Richard A.; Goodale, Melvyn A.

doi:10.1007/s00221-003-1587-1

Cited by 364 publications

(303 citation statements)

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“…Recent imaging results using saccade and pointing tasks also support this notion. Essentially every fMRI study conducted to date has reported either areas showing a saccade preference (Simon et al, 2002;Medendorp et al, 2005) or areas showing a pointing preference (Connolly et al, 2000;Astafiev et al, 2003;Connolly et al, 2003) but not a dissociation between two distinct networks with one selective for saccades and the other for reaching (although in some cases this may have been because establishing such a segregation was not the main goal of the paper and in others because the authors only looked for stronger activation for one effector). One positron emission tomography study reported an anatomical segregation for reaching and saccades (Kawashima et al, 1996), but the Talairach coordinates of the reach-related region (30, Ϫ35, 50) place it in a more anterior area, in the vicinity of primary somatosensory cortex.…”

Section: Discussionmentioning

confidence: 99%

“…Several existing imaging studies have taken advantage of this property in an effort to identify the human homologs of LIP and PRR by searching for task-specific or effector-specific areas in regions such as the intraparietal sulcus (IPS). However, the results of these studies have been hard to interpret with regard to the prevailing view that effector-specific modules populate the PPC (for review, see Grefkes and Fink, 2005;Culham and Valyear, 2006) (for examples, see Kawashima et al, 1996;Connolly et al, 2000;Simon et al, 2002;Astafiev et al, 2003;Connolly et al, 2003;Medendorp et al, 2003Medendorp et al, , 2005.…”

Section: Introductionmentioning

confidence: 99%

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Specificity of Human Cortical Areas for Reaches and Saccades

Levy¹,

Schluppeck²,

Heeger³

et al. 2007

J. Neurosci.

131

123

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Electrophysiological studies in monkeys have identified effector-related regions in the posterior parietal cortex (PPC). The lateral intraparietal area, for example, responds preferentially for saccades, whereas the parietal reach region responds preferentially for arm movements. However, the degree of effector selectivity actually observed is limited; each area contains neurons selective for the nonpreferred effector, and many neurons in both areas respond for both effectors. We used functional magnetic resonance imaging to assess the degree of effector preference at the population level, focusing on topographically organized regions in the human PPC [visual area V7, intraparietal sulcus 1 (IPS1), and IPS2]. An event-related design adapted from monkey experiments was used. In each trial, an effector cue preceded the appearance of a spatial target, after which a Go signal instructed subjects to produce the specified movement with the specified effector. Our results show that the degree of effector specificity is limited in many cortical areas and transitions gradually from saccade to reach preference as one moves through the hierarchy of areas in the occipital, parietal, and frontal cortices. Saccade preference was observed in visual cortex, including early areas and V7. IPS1 exhibited balanced activation to saccades and reaches, whereas IPS2 showed a weak but significant preference for reaches. In frontal cortex, areas near the central sulcus showed a clear and absolute preference for reaches, whereas the frontal eye field showed little or no effector selectivity. Although these results contradict many theoretical conclusions about effector specificity, they are compatible with the complex picture arising from electrophysiological studies and also with previous imaging studies that reported mostly overlapping saccade-and arm-related activation. The results are also compatible with theories of efficient coding in cortex.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Specificity of Human Cortical Areas for Reaches and Saccades

Levy¹,

Schluppeck²,

Heeger³

et al. 2007

J. Neurosci.

131

123

View full text Add to dashboard Cite

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“…Another strong case of functional specificity for a simple visual dimension is color (15), for which recent evidence from both fMRI and single-unit recording indicates the existence of multiple millimeter-sized color-selective "globs" in posterior inferotemporal cortex in macaques (16,17). Other brain regions have been reported to be selectively engaged in processing information about biological motion (18), visually guided reaching (19), and grasping (20). For most cases in the neuroimaging literature, however, the main claim is one of regional specificity (i.e., that the implicated function activates this region more than other brain regions) rather than of functional specificity (i.e., that the implicated region is more engaged for this function than other functions).…”

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confidence: 99%

Functional specificity in the human brain: A window into the functional architecture of the mind

Kanwisher

2010

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

797

623

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Is the human mind/brain composed of a set of highly specialized components, each carrying out a specific aspect of human cognition, or is it more of a general-purpose device, in which each component participates in a wide variety of cognitive processes? For nearly two centuries, proponents of specialized organs or modules of the mind and brain-from the phrenologists to Broca to Chomsky and Fodor-have jousted with the proponents of distributed cognitive and neural processing-from Flourens to Lashley to McClelland and Rumelhart. I argue here that research using functional MRI is beginning to answer this long-standing question with new clarity and precision by indicating that at least a few specific aspects of cognition are implemented in brain regions that are highly specialized for that process alone. Cortical regions have been identified that are specialized not only for basic sensory and motor processes but also for the high-level perceptual analysis of faces, places, bodies, visually presented words, and even for the very abstract cognitive function of thinking about another person's thoughts. I further consider the as-yet unanswered questions of how much of the mind and brain are made up of these functionally specialized components and how they arise developmentally.brain imaging | modularity | functional MRI | fusiform face area U nderstanding the nature of the human mind is arguably the greatest intellectual quest of all time. It is also one of the most challenging, requiring the combined insights not only of psychologists, computer scientists, and neuroscientists but of thinkers in nearly every intellectual pursuit, from biology and mathematics to art and anthropology. Here, I discuss one currently fruitful component of this grand enterprise: the effort to infer the architecture of the human mind from the functional organization of the human brain.The idea that the human mind/brain is made up of highly specialized components began with the Viennese physician Franz Joseph Gall (1758-1828). Gall proposed that the brain is the seat of the mind, that the mind is composed of distinct mental faculties, and that each mental faculty resides in a specific brain organ. A heated debate on localization of function in the brain raged over the next century (SI Text), with many of the major figures in the history of neuroscience weighing in (Broca, Brodmann, and Ferrier in favor, and Flourens, Golgi, and Lashley opposed). By the early 20th century, a consensus emerged that at least basic sensory and motor functions reside in specialized brain regions.The debate did not end there, however. Today, a century later, two questions are still fiercely contested. First, how functionally specialized are regions of the brain? The concept of functional specialization is not all or none but a matter of degree; a cortical region might be only slightly more engaged in one mental function than another, or it might be exclusively engaged in a single mental function. Many neuroscientists today challenge the strong (exclusive) version of ...

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“…MIP is active during reaching to targets, pointing, and arm movements (34)(35)(36). Other areas in the intraparietal sulcus are thought to mediate sensory-motor transformation for other effectors: the lateral intraparietal area (LIP) represents visual targets and saccades (19,24,37); the anterior intraparietal area (AIP) is active during hand grasping of 3D objects (38,39).…”

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confidence: 99%

Spatial remapping of touch: Confusion of perceived stimulus order across hand and foot

Schicke

Röder

2006

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

139

113

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The ''body schema,'' a spatial representation of the body in its environment, has been suggested to be an emergent property of a widespread network of effector-specific frontal and parietal areas, many of which integrate sensory input from the different modalities. On a behavioral level, such multimodality has been shown with temporal order judgment tasks, in which participants decide which of the two hands received a tactile stimulus first. The accuracy of these judgments is influenced by body posture, indicating that tactile stimuli are not simply represented in an anatomical reference frame, but are transformed into external spatial coordinates. So far, these studies have only investigated the hands. It is therefore unclear whether a default remapping of touch into external space is a special feature of visual-manual control or whether all body parts are represented in a common nonanatomically anchored reference frame. In the present study, blindfolded participants made temporal order judgments of stimuli presented to both hands, both feet, or one hand and one foot. The stimulated limbs were held in either a parallel or a crossed posture. Judgments were equally impaired by limb crossing in all limb combinations (hands only, feet only, hand and foot). These results suggest a remapping of tactile location of all body parts into a nonanatomically anchored and, importantly, common reference frame rather than a specific remapping for eye-hand coordination only.body schema ͉ feet ͉ tactile ͉ temporal order judgment ͉ visual-manual control

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FMRI evidence for a 'parietal reach region' in the human brain

Cited by 364 publications

References 25 publications

Specificity of Human Cortical Areas for Reaches and Saccades

Specificity of Human Cortical Areas for Reaches and Saccades

Functional specificity in the human brain: A window into the functional architecture of the mind

Spatial remapping of touch: Confusion of perceived stimulus order across hand and foot

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