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Jennifer R. Melcher - One of the best experts on this subject based on the ideXlab platform.
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Somatosensory Pulsatile Tinnitus Syndrome: Somatic Testing Identifies a Pulsatile Tinnitus Subtype That Implicates the Somatosensory System
Trends in amplification, 2008Co-Authors: Robert A. Levine, Eui-cheol Nam, Jennifer R. MelcherAbstract:A new tinnitus syndrome is described: high-pitched, cardiac-synchronous tinnitus, whose pulsations are suppressed by strong contractions or compressions of the neck and jaw muscles (somatic testing). 14 cases, 6 non-lateralized and 8 unilateral, are reported. In the non-lateralized cases, onset was bilateral. In the one intermittent case, while her tinnitus was absent her pulsatile tinnitus could be induced by somatic testing. No etiology was found from physical examination, imaging, or ancillary testing. Because these cases of pulsatile tinnitus can be both induced and suppressed by activation of the Somatosensory System of the head or upper lateral neck, we propose that this syndrome is occurring from (a) cardiac synchronous Somatosensory activation of the central auditory pathway or (b) failure of the Somatosensory-auditory central nervous System interactions to suppress cardiac somatosounds.
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Evidence for a tinnitus subgroup responsive to Somatosensory based treatment modalities.
Progress in Brain Research, 2007Co-Authors: Robert A. Levine, Yahav Oron, Jennifer R. MelcherAbstract:Abstract Studies have established that the Somatosensory System of the upper cervical region and head can be intimately involved in tinnitus. Tinnitus can arise directly from a disorder of the head and upper neck through activation of the Somatosensory System. “Somatic testing” (a series of strong muscle contractions of the head and neck) can (1) modulate the tinnitus percept of ∼80% of people with ongoing tinnitus, and (2) elicit a sound percept in ∼50% of people with no tinnitus. These somatic phenomena are equally prevalent among people with or without functioning cochlea. Likely neural pathways underlying both the induction and modulation of tinnitus have been revealed in animal studies. Because somatic influences are fundamental to the operation of the auditory System, in general, and to tinnitus, in particular, somatic testing should be incorporated into all evaluations of tinnitus (1) to improve understanding of the role of the Somatosensory System in any individual and (2) to identify subgroups of tinnitus patients who may respond to a particular treatment modality (as has already been shown for the tinnitus associated with temporomandibular disorder). Our clinical experience and review of reports of treatment modalities directed toward the Somatosensory System supports the hypothesis that these modalities can benefit individuals with symmetric hearing thresholds but asymmetric widely fluctuating tinnitus. Treatment modalities involving the Somatosensory System should be re-assessed by targeting this tinnitus subgroup.
Miguel A. L. Nicolelis - One of the best experts on this subject based on the ideXlab platform.
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Behavioral Properties of the Trigeminal Somatosensory System in Rats Performing Whisker-Dependent Tactile Discriminations
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2001Co-Authors: David J. Krupa, Matthew S. Matell, Amy J. Brisben, Laura M. O. Oliveira, Miguel A. L. NicolelisAbstract:To address several fundamental questions regarding how multiwhisker tactile stimuli are integrated and processed by the trigeminal Somatosensory System, a novel behavioral task was developed that required rats to discriminate the width of either a wide or narrow aperture using only their large mystacial vibrissae. Rats quickly acquired this task and could accurately discriminate between apertures of very similar width. Accurate discriminations required a large number of intact facial whiskers. Systematic removal of individual whiskers caused a decrease in performance that was directly proportional to the number of whiskers removed, indicating that tactile information from multiple whiskers is integrated as rats gauge aperture width. In different groups of rats, different sets of whiskers were removed in patterns that preferentially left whisker rows or whisker arcs intact. These different whisker removals caused similar decreases in performance, indicating that individual whiskers within the vibrissal array are functionally equivalent during performance of this task. Lesions of the barrel cortex abolished the ability of rats to discriminate, demonstrating that this region is critically involved in this tactile behavior. Interestingly, sectioning the facial nerve, which abolished whisker movements, did not affect the ability to perform accurate discriminations, indicating that active whisker movements are not necessary for accurate performance of the task. Collectively, these results indicate that the trigeminal Somatosensory System forms internal representations of external stimuli (in this case, aperture width) by integrating tactile input from many functionally equivalent facial whiskers and that the vibrissal array can function as a fine-grained distance detector without active whisker movements.
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Thalamocortical and corticocortical interactions in the Somatosensory System.
Progress in brain research, 2001Co-Authors: Miguel A. L. Nicolelis, Marshall G. Hussain ShulerAbstract:Publisher Summary The classic feedforward model of touch provided a fundamental blueprint for the development of Somatosensory research in the past five decades, a variety of experimental findings, and theoretical arguments demonstrate that, this model no longer offers an accurate description on how tactile perception emerges in the mammalian brain. Anatomical, physiological, and computational arguments favor the hypothesis that tactile perception emerges through interactive and recurrent interactions between multiple cortical and subcortical levels that define the mammalian Somatosensory System. Central to this recurrent model of touch is the experimental demonstration that the massive corticofugal projections, that originate in the neocortex and reach most of the subcortical structures that form the Somatosensory System, may play as relevant a role in tactile information processing as the parallel feed forward pathways of this System.
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Behavioral modulation of tactile responses in the rat Somatosensory System.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1999Co-Authors: Erika E. Fanselow, Miguel A. L. NicolelisAbstract:We investigated the influence of four different behavioral states on tactile responses recorded simultaneously via arrays of microwires chronically implanted in the vibrissal representations of the rat ventral posterior medial nucleus (VPM) of the thalamus and the primary Somatosensory cortex (SI). Brief (100 μsec) electrical stimuli delivered via a cuff electrode to the infraorbital nerve yielded robust sensory responses in VPM and SI during states of quiet immobility. However, significant reductions in tactile response magnitude and latency were observed in VPM and SI during large-amplitude, exploratory movements of the whiskers (at ∼4–6 Hz). During small-amplitude, 7–12 Hz whisker-twitching movements, a significant reduction in SI response magnitude and an increase in VPM and SI response latencies were observed as well. When pairs of stimuli with interstimulus intervals 25 msec. These response patterns were correlated with the amount and duration of postexcitatory firing suppression observed in VPM and SI during each of these behaviors. On the basis of these results, we propose that sensory responses are dynamically modulated during active tactile exploration to optimize detection of different types of stimuli. During quiet immobility, the Somatosensory System seems to be optimally tuned to detect the presence of single stimuli. In contrast, during whisker movements and other exploratory behaviors, the System is primed to detect the occurrence of rapid sequences of tactile stimuli, which are likely to be generated by multiple whisker contacts with objects during exploratory activity.
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Immediate and simultaneous sensory reorganization at cortical and subcortical levels of the Somatosensory System
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Barbara M. Faggin, Kevin Tri Nguyen, Miguel A. L. NicolelisAbstract:The occurrence of cortical plasticity during adulthood has been demonstrated using many experimental paradigms. Whether this phenomenon is generated exclusively by changes in intrinsic cortical circuitry, or whether it involves concomitant cortical and subcortical reorganization, remains controversial. Here, we addressed this issue by simultaneously recording the extracellular activity of up to 135 neurons in the primary Somatosensory cortex, ventral posterior medial nucleus of the thalamus, and trigeminal brainstem complex of adult rats, before and after a reversible sensory deactivation was produced by subcutaneous injections of lidocaine. Following the onset of the deactivation, immediate and simultaneous sensory reorganization was observed at all levels of the Somatosensory System. No statistical difference was observed when the overall spatial extent of the cortical (9.1 ± 1.2 whiskers, mean ± SE) and the thalamic (6.1 ± 1.6 whiskers) reorganization was compared. Likewise, no significant difference was found in the percentage of cortical (71.1 ± 5.2%) and thalamic (66.4 ± 10.7%) neurons exhibiting unmasked sensory responses. Although unmasked cortical responses occurred at significantly higher latencies (19.6 ± 0.3 ms, mean ± SE) than thalamic responses (13.1 ± 0.6 ms), variations in neuronal latency induced by the sensory deafferentation occurred as often in the thalamus as in the cortex. These data clearly demonstrate that peripheral sensory deafferentation triggers a System-wide reorganization, and strongly suggest that the spatiotemporal attributes of cortical plasticity are paralleled by subcortical reorganization.
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Active tactile exploration influences the functional maturation of the Somatosensory System
Journal of neurophysiology, 1996Co-Authors: Miguel A. L. Nicolelis, L. M. O. De Oliveira, Rick C.s. Lin, John K. ChapinAbstract:1. The hypothesis that active exploration of objects is required for the functional maturation of neuronal circuits subserving tactile perception was tested by subjecting 8- to 11-day old rats to a complete unilateral section of the facial nerve. This procedure selectively abolished whisker protraction movements without affecting the sensory innervation of the facial vibrissae, the tactile organs used by rats to discriminate object texture and shape. 2. Six to 14 mo after the facial nerve section, simultaneous recordings of neuronal ensembles located in the ventral posterior medial nucleus (VPM) of the thalamus revealed a marked reduction in receptive field (RF) size (in terms of number of whiskers), and the formation of abnormal RF surrounds, spanning the face and contiguous body regions. In addition, the directional organization of VPM RFs, represented by caudal to rostral shifts in RF centers over 30 ms following whisker stimulation, was greatly reduced in these animals. 3. These results suggest that neonatal active tactile exploration is required to establish normal spatiotemporal patterning of neuronal RFs within the Somatosensory System, and consequently, to develop normal tactile perception.
Robert A. Levine - One of the best experts on this subject based on the ideXlab platform.
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Somatosensory Pulsatile Tinnitus Syndrome: Somatic Testing Identifies a Pulsatile Tinnitus Subtype That Implicates the Somatosensory System
Trends in amplification, 2008Co-Authors: Robert A. Levine, Eui-cheol Nam, Jennifer R. MelcherAbstract:A new tinnitus syndrome is described: high-pitched, cardiac-synchronous tinnitus, whose pulsations are suppressed by strong contractions or compressions of the neck and jaw muscles (somatic testing). 14 cases, 6 non-lateralized and 8 unilateral, are reported. In the non-lateralized cases, onset was bilateral. In the one intermittent case, while her tinnitus was absent her pulsatile tinnitus could be induced by somatic testing. No etiology was found from physical examination, imaging, or ancillary testing. Because these cases of pulsatile tinnitus can be both induced and suppressed by activation of the Somatosensory System of the head or upper lateral neck, we propose that this syndrome is occurring from (a) cardiac synchronous Somatosensory activation of the central auditory pathway or (b) failure of the Somatosensory-auditory central nervous System interactions to suppress cardiac somatosounds.
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Evidence for a tinnitus subgroup responsive to Somatosensory based treatment modalities.
Progress in Brain Research, 2007Co-Authors: Robert A. Levine, Yahav Oron, Jennifer R. MelcherAbstract:Abstract Studies have established that the Somatosensory System of the upper cervical region and head can be intimately involved in tinnitus. Tinnitus can arise directly from a disorder of the head and upper neck through activation of the Somatosensory System. “Somatic testing” (a series of strong muscle contractions of the head and neck) can (1) modulate the tinnitus percept of ∼80% of people with ongoing tinnitus, and (2) elicit a sound percept in ∼50% of people with no tinnitus. These somatic phenomena are equally prevalent among people with or without functioning cochlea. Likely neural pathways underlying both the induction and modulation of tinnitus have been revealed in animal studies. Because somatic influences are fundamental to the operation of the auditory System, in general, and to tinnitus, in particular, somatic testing should be incorporated into all evaluations of tinnitus (1) to improve understanding of the role of the Somatosensory System in any individual and (2) to identify subgroups of tinnitus patients who may respond to a particular treatment modality (as has already been shown for the tinnitus associated with temporomandibular disorder). Our clinical experience and review of reports of treatment modalities directed toward the Somatosensory System supports the hypothesis that these modalities can benefit individuals with symmetric hearing thresholds but asymmetric widely fluctuating tinnitus. Treatment modalities involving the Somatosensory System should be re-assessed by targeting this tinnitus subgroup.
T. P. Pons - One of the best experts on this subject based on the ideXlab platform.
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Cortically induced thalamic plasticity in the primate Somatosensory System
Nature neuroscience, 1998Co-Authors: E.r. Ergenzinger, M.m. Glasier, J.o. Hahm, T. P. PonsAbstract:The influence of cortical feedback on receptive field organization in the thalamus was assessed in the primate Somatosensory System. Chronic and acute suppression of neuronal activity in primary Somatosensory cortex resulted in a striking enlargement of receptive fields in the ventroposterior thalamus. This finding demonstrates a dramatic 'top-down' influence of cortex on receptive field size in the Somatosensory thalamus. In addition, this result has important implications for studies of adult neuronal plasticity because it indicates that changes in 'higher-order' areas of the brain can trigger extensive changes in the receptive field characteristics of neurons located earlier in the processing pathway.
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Serial processing in the Somatosensory System of macaques
Somesthesis and the Neurobiology of the Somatosensory Cortex, 1996Co-Authors: T. P. PonsAbstract:Electrophysiological, anatomical and immunocytochemical evidence for serial processing in the macaque Somatosensory System is reviewed. The results from these studies are then compared with similar or dissimilar results obtained in other animal species. It is argued that the bulk of the current evidence strongly supports the view that the input supplying the major somatic drive to the second Somatosensory area is from postcentral Somatosensory cortex.
Eui-cheol Nam - One of the best experts on this subject based on the ideXlab platform.
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Somatosensory Pulsatile Tinnitus Syndrome: Somatic Testing Identifies a Pulsatile Tinnitus Subtype That Implicates the Somatosensory System
Trends in amplification, 2008Co-Authors: Robert A. Levine, Eui-cheol Nam, Jennifer R. MelcherAbstract:A new tinnitus syndrome is described: high-pitched, cardiac-synchronous tinnitus, whose pulsations are suppressed by strong contractions or compressions of the neck and jaw muscles (somatic testing). 14 cases, 6 non-lateralized and 8 unilateral, are reported. In the non-lateralized cases, onset was bilateral. In the one intermittent case, while her tinnitus was absent her pulsatile tinnitus could be induced by somatic testing. No etiology was found from physical examination, imaging, or ancillary testing. Because these cases of pulsatile tinnitus can be both induced and suppressed by activation of the Somatosensory System of the head or upper lateral neck, we propose that this syndrome is occurring from (a) cardiac synchronous Somatosensory activation of the central auditory pathway or (b) failure of the Somatosensory-auditory central nervous System interactions to suppress cardiac somatosounds.
