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Somatosensory system

About: Somatosensory system is a research topic. Over the lifetime, 6371 publications have been published within this topic receiving 316900 citations.


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Journal ArticleDOI
24 Dec 1993-Science
TL;DR: In cat dorsal column nuclei (DCN), the injection of local anesthetic into the receptive fields of DCN neurons resulted in the emergence of a new receptive field in all 13 neurons studied, indicating mechanisms underlying somatotopic reorganization exist at the earliest stages of somatosensory processing.
Abstract: Altered sensory input can result in the reorganization of somatosensory maps in the cerebral cortex and thalamus, but the extent to which reorganization occurs at lower levels of the somatosensory system is unknown. In cat dorsal column nuclei (DCN), the injection of local anesthetic into the receptive fields of DCN neurons resulted in the emergence of a new receptive field in all 13 neurons studied. New receptive fields emerged rapidly (within minutes), sometimes accompanied by changes in adaptation rates and stimulus selectivity, suggesting that the new fields arose from the unmasking of previously ineffective inputs. Receptive field reorganization was not imposed by descending cortical inputs to the DCN, because comparable results were obtained in 10 additional cells when the somatosensory and motor cortex were removed before recording. These results suggest that mechanisms underlying somatotopic reorganization exist at the earliest stages of somatosensory processing. Such mechanisms may participate in adaptive responses of the nervous system to injury or continuously changing sensory stimulation.

147 citations

Journal ArticleDOI
TL;DR: The data suggest that chronic neuropathic pain is associated with altered thalamic anatomy and activity, which may result in disturbed thalamocortical circuits, which could result in the constant perception of pain.
Abstract: Human brain imaging has revealed that acute pain results from activation of a network of brain regions, including the somatosensory, insular, prefrontal, and cingulate cortices. In contrast, many investigations report little or no alteration in brain activity associated with chronic pain, particularly neuropathic pain. It has been hypothesized that neuropathic pain results from misinterpretation of thalamocortical activity, and recent evidence has revealed altered thalamocortical rhythm in individuals with neuropathic pain. Indeed, it was suggested nearly four decades ago that neuropathic pain may be maintained by a discrete central generator, possibly within the thalamus. In this investigation, we used multiple brain imaging techniques to explore central changes in subjects with neuropathic pain of the trigeminal nerve resulting in most cases (20 of 23) from a surgical event. Individuals with chronic neuropathic pain displayed significant somatosensory thalamus volume loss (voxel-based morphometry) which was associated with decreased thalamic reticular nucleus and primary somatosensory cortex activity (quantitative arterial spin labeling). Furthermore, thalamic inhibitory neurotransmitter content was significantly reduced (magnetic resonance spectroscopy), which was significantly correlated to the degree of functional connectivity between the somatosensory thalamus and cortical regions including the primary and secondary somatosensory cortices, anterior insula, and cerebellar cortex. These data suggest that chronic neuropathic pain is associated with altered thalamic anatomy and activity, which may result in disturbed thalamocortical circuits. This disturbed thalamocortical activity may result in the constant perception of pain.

147 citations

Journal ArticleDOI
TL;DR: The dorsal nerve of the penis or clitoris, a branch of the pudendal nerve, was stimulated while averaged evoked responses over the spinal cord, sensory cortex, and bulbocavernosus muscle were recorded in a series of normal subjects.
Abstract: • The dorsal nerve of the penis or clitoris, a branch of the pudendal nerve, was stimulated while averaged evoked responses over the spinal cord, sensory cortex, and bulbocavernosus muscle were recorded in a series of normal subjects. The morphologic features, peak latencies, and peripheral and central conduction times were compared with spinal and cortical evoked responses from the posterior tibial nerve. These tests are of potential clinical importance in the evaluation of sacral nerve root or plexus injuries and bowel, bladder, or sexual dysfunction.

147 citations

Journal ArticleDOI
TL;DR: Characterizing the location and timing of the CC evoked responses during the 1 s period after a painful laser stimulus provides direct evidence that activations underlying the processing of nociceptive information can occur simultaneously in the “medial” and “lateral” subsystems.
Abstract: The cingulate cortex (CC) as a part of the "medial" pain subsystem is generally assumed to be involved in the affective and/or cognitive dimensions of pain processing, which are viewed as relatively slow processes compared with the sensory-discriminative pain coding by the lateral second somatosensory area (SII)-insular cortex. The present study aimed at characterizing the location and timing of the CC evoked responses during the 1 s period after a painful laser stimulus, by exploring the whole rostrocaudal extent of this cortical area using intracortical recordings in humans. Only a restricted area in the median CC region responded to painful stimulation, namely the posterior midcingulate cortex (pMCC), the location of which is consistent with the so-called "motor CC" in monkeys. Cingulate pain responses showed two components, of which the earliest peaked at latencies similar to those obtained in SII. These data provide direct evidence that activations underlying the processing of nociceptive information can occur simultaneously in the "medial" and "lateral" subsystems. The existence of short-latency pMCC responses to pain further indicates that the "medial pain system" is not devoted exclusively to the processing of emotional information, but is also involved in fast attentional orienting and motor withdrawal responses to pain inputs. These functions are, not surprisingly, conducted in parallel with pain intensity coding and stimulus localization specifically subserved by the sensory-discriminative "lateral" pain system.

147 citations

Journal ArticleDOI
TL;DR: Recurrent transcranial magnetic stimulation is used to probe the connection between primary somatosensory cortex (S1) and early visual cortex (V1 and neighboring areas), combining rTMS with positron emission tomography (PET).
Abstract: Crossmodal plasticity occurs when loss of input in one sensory modality leads to reorganization in brain representations of other sensory modalities. In congenital blindness the visual cortex becomes responsive to somatosensory input such as occurs during Braille reading. The route by which somatosensory information reaches the visual cortex is not known. Here, we used repetitive transcranial magnetic stimulation (rTMS) to probe the connection between primary somatosensory cortex (S1) and early visual cortex (V1 and neighboring areas), combining rTMS with positron emission tomography (PET). We applied stimulation over S1 in sighted, early blind and late blind individuals. Baseline regional cerebral blood flow in occipital cortex was highest in early blind and lowest in late blind individuals. Only the early blind group showed significant activation of early visual areas when rTMS was delivered over S1. This activation was significantly higher in early than in late blind, but not relative to sighted controls. These results are consistent with the hypothesis that tactile information may reach early visual areas in early blind humans through cortico-cortical pathways, possibly supporting enhanced tactile information processing.

146 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023463
2022986
2021238
2020233
2019234