Remodeling of somotasensory hand representations following cerebral lesions in humans

Rapp, Brenda; Hendel, Sharma K.; Medina, Jared

doi:10.1097/00001756-200202110-00007

Cited by 41 publications

(43 citation statements)

References 23 publications

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“…Nonetheless, the observation of better-than-chance accuracy in locating undetected stimuli is a necessary (if not sufficient) result to support the conclusion that localization is not contingent on detection. Altogether, the present findings could be taken as demonstrating a double dissociation between tactile detection and localization and are therefore consistent with neuropsychological reports of a double dissociation between these same processes (Paillard et al, 1983;Halligan et al, 1995;Rossetti et al, 1995;Rapp et al, 2002).…”

Section: Discussionsupporting

confidence: 92%

“…A similar somatosensory deficit (as might be called "numb touch") was reported by Rossetti et al (1995) in their study of a man with a left thalamic lesion. The ability of these patients to locate tactile stimuli in the absence of conscious detection contrasts with classic reports (Head and Holmes, 1911) and more recent demonstrations (Halligan et al, 1995;Rapp et al, 2002) of patients who were unable to accurately locate stimuli that they could successfully detect. The combination of these findings indicates that detecting and locating tactile stimuli are doubly dissociable processes, presumably performed by different neural structures.…”

Section: Introductioncontrasting

confidence: 86%

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Dissociating Detection from Localization of Tactile Stimuli

Harris¹,

Thein²,

Clifford³

2004

J. Neurosci.

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In what they described as "a tactile analog of blindsight," Paillard et al. (1983) reported the case of a woman with damage to the left parietal cortex who was profoundly impaired in detecting tactile stimuli but could nonetheless correctly identify their location (also Rossetti et al., 1995). This stands in direct contrast to reports of neurological patients who were unable to accurately locate stimuli that they could successfully detect (Head and Holmes, 1911; Halligan et al., 1995; Rapp et al., 2002). The combination of these findings suggests that detecting and locating tactile stimuli are doubly dissociable processes, presumably mediated by different neural structures. We conducted four psychophysical experiments seeking evidence for such a double dissociation in neurologically intact subjects. We compared people's accuracy in detecting versus locating a tactile stimulus presented to one of four fingers and followed by a vibrotactile mask presented to all four fingers. Accuracy scores for both the yes-no detection and four-alternative forced-choice location judgments were converted to a bias-free measure (d), which revealed that subjects were better at detecting than locating the stimulus. Detection was also more sensitive than localization to manipulations involving the mask: detection accuracy increased more steeply than localization accuracy as the target-mask interval increased, and detection, but not localization, was affected by changes in the mask frequency. By comparing these results with simulated data generated by computational models, we conclude that detection and localization are not mutually independent as previous neurological studies might suggest, but rather localization is subsequent to detection in a serially organized sensory processing hierarchy.

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Section: Discussionsupporting

confidence: 92%

Section: Introductioncontrasting

confidence: 86%

Dissociating Detection from Localization of Tactile Stimuli

Harris¹,

Thein²,

Clifford³

2004

J. Neurosci.

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show abstract

“…Head and Holmes (1911) first reported a number of patients who, following cortical lesion, were unable to indicate where they had been touched (atopognosia), though their ability to detect that they had been touched was apparently unimpaired. Several authors have suggested that localisation errors mainly involve shifts of perceived location proximal to the actual location of touch (e.g., Critchley, 1953;Halligan et al, 1995;Rapp, Hendel, & Medina, 2002). A more complex pattern of mislocalisations, however, was reported by Denny-Brown, Meyer, and Horenstein (1952) who found in one patient that the perceived locations of touches were funnelled towards the wrist and the ankles, resulting in effective foreshortening of the upper arm and leg.…”

Section: Localisation Of Touch On the Body Surfacementioning

confidence: 97%

More than skin deep: Body representation beyond primary somatosensory cortex

2010

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The neural circuits underlying initial sensory processing of somatic information are relatively well understood. In contrast, the processes that go beyond primary somatosensation to create more abstract representations related to the body are less clear. In this review, we focus on two classes of higher-order processing beyond somatosensation. Somatoperception refers to the process of perceiving the body itself, and particularly of ensuring somatic perceptual constancy.We review three key elements of somatoperception: (a) remapping information from the body surface into an egocentric reference frame (b) exteroceptive perception of objects in the external world through their contact with the body and (c) interoceptive percepts about the nature and state of the body itself. Somatorepresentation, in contrast, refers to the essentially cognitive process of constructing semantic knowledge and attitudes about the body, including: (d) lexicalsemantic knowledge about bodies generally and one's own body specifically, (e) configural knowledge about the structure of bodies, (f) emotions and attitudes directed towards one's own body, and (g) the link between physical body and psychological self. We review a wide range of neuropsychological, neuroimaging and neurophysiological data to explore the dissociation between these different aspects of higher somatosensory function.Body Beyond SI 3

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“…Attending to which finger was stimulated selectively activated the right temporo-parietal junction in a functional magnetic resonance (fMRI) study (Van Boven, Ingeholm, Beauchamp, Bikle, & Ungerleider, 2005). Finally, neuropsychological and transcranial magnetic stimulation (TMS) studies found that damage or disruption to the parietal cortex impairs the localization of both tactile and noxious stimuli (Paillard, Michel, & Stelmach, 1983;Porro et al, 2007;Rapp et al, 2002).…”

Section: Origin Of the Localization Biasesmentioning

confidence: 99%

“…These biases can be thought of as reflecting a distorted 'perceptual map' of the skin surface (Rapp, Hendel, & Medina, 2002;Trojan et al, 2006). Importantly, biases (i.e.…”

Section: Introductionmentioning

confidence: 99%

A supramodal representation of the body surface

et al. 2011

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The ability to accurately localize both tactile and painful sensations on the body is one of the most important functions of the somatosensory system. Most accounts of localization refer to the systematic spatial relation between skin receptors and cortical neurons. The topographic organization of somatosensory neurons in the brain provides a map of the sensory surface. However, systematic distortions in perceptual localization tasks suggest that localizing a somatosensory stimulus involves more than simply identifying specific active neural populations within a somatotopic map. Thus, perceptual localization may depend on both afferent inputs and other unknown factors. In four experiments, we investigated whether localization biases vary according to the specific skin regions and subset of afferent fibers stimulated. We represented localization errors as a 'perceptual map' of skin locations.We compared the perceptual maps of stimuli that activate A (innocuous touch), A (pinprick pain), and C fibers (non-painful heat) on both the hairy and glabrous skin of the left hand. Perceptual maps exhibited systematic distortions that strongly depended on the skin region stimulated. We found systematic distal and radial (i.e, toward the thumb) biases in localization of touch, pain, and heat on the hand dorsum. A less consistent proximal bias was found on the palm. These distortions were independent of the population of afferent fibers stimulated, and also independent of the response modality used to report localization. We argue that these biases are likely to have a central origin, and result from a supramodal representation of the body surface.

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Remodeling of somotasensory hand representations following cerebral lesions in humans

Cited by 41 publications

References 23 publications

Dissociating Detection from Localization of Tactile Stimuli

Dissociating Detection from Localization of Tactile Stimuli

More than skin deep: Body representation beyond primary somatosensory cortex

A supramodal representation of the body surface

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