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Nobuhiro Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Gentle Perineal Skin Stimulation for Control of Nocturia.
Anatomical record (Hoboken N.J. : 2007), 2019Co-Authors: Harumi Hotta, Nobuhiro WatanabeAbstract:One of the major causes of nocturia is overactive bladder (OAB). Somatic afferent nerve stimuli are used for treating OAB. However, clinical evidence for the efficacy of this treatment is insufficient due to the lack of appropriate control stimuli. Studies on anesthetized animals, which eliminate emotional factors and placebo effects, have demonstrated an influence of somatic stimuli on urinary bladder functions and elucidated the underlying mechanisms. In general, the effects of somatic stimuli are dependent on the modality, location, and physical characteristics of the stimulus. Recently we showed that gentle stimuli applied to the perineal Skin using a soft elastomer roller inhibited micturition contractions to a greater extent than a roller with a hard surface. Studies aiming to elucidate the neural mechanisms of gentle Stimulation-induced inhibition reported that 1-10 Hz discharges of low-threshold cutaneous mechanoreceptive Aβ, Aδ, and C fibers evoked during Stimulation with an elastomer roller inhibited the micturition reflex by activating the spinal cord opioid system, thereby reducing both ascending and descending transmission between bladder and pontine micturition center. The present review will provide a brief summary of (1) the effect of somatic electrical Stimulation on the micturition reflex, (2) the effect of gentle mechanical Skin Stimulation on the micturition reflex, (3) the afferent, efferent, and central mechanisms underlying the effects of gentle Stimulation, and (4) a translational clinical study demonstrating the efficacy of gentle Skin stimuli for treating nocturia in the elderly with OAB by using the two roller types inducing distinct effects on rat micturition contractions. Anat Rec, 302:1824-1836, 2019. © 2019 American Association for Anatomy.
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Age-Related Changes in Neuromodulatory Control of Bladder Micturition Contractions Originating in the Skin
Frontiers Media S.A., 2018Co-Authors: Harumi Hotta, Harue Suzuki, Kaori Iimura, Nobuhiro WatanabeAbstract:The brainstem is essential for producing micturition contractions of the urinary bladder. Afferent input from perineal Skin evoked by gentle mechanical Stimulation inhibits micturition contractions by decreasing both ascending and descending transmissions between the brainstem and spinal cord. Dysfunction of this inhibitory mechanism may be one cause of the increase in the prevalence of overactive bladder in old age. The aim of this study was to examine effect of aging on function of Skin afferent fibers that inhibit bladder micturition contractions in rats. We used anesthetized male rats in three different age groups: young adult (4–5 months old), middle aged (6–9 months old), and aged (27–30 months old). The bladder was expanded to produce isovolumetric rhythmic micturition contractions. Skin afferent fibers were activated for 1 min either by electrical Stimulation (0.5 ms, 0.2–10 V, 0.1–10 Hz) of the cutaneous branch of the pudendal nerve (CBPN) or by gentle mechanical Skin Stimulation with an elastomer roller. When Skin afferent nerves were activated electrically, micturition contractions were inhibited in a similar manner in all age groups, with long latency inhibition induced by excitation of Aβ fibers and short latency inhibition by additional Aδ and C fiber excitation (at 1–10 Hz). On the contrary, when Skin afferent nerves were activated mechanically by rolling, latency of inhibition following rolling Stimulation was prolonged in aged rats. Single unitary afferent nerve activity of low-threshold mechanoreceptors (LTMs) from the cutaneous nerve was recorded. The discharge rate during rolling was not significantly reduced in Aβ units but was much lower in Aδ and C units in aged rats (0.4 and 0.5 Hz, respectively) than in young adult rats (3 and 7 Hz). These results suggest that the neural mechanism that inhibits bladder micturition contractions by Skin afferent input is well maintained in old age, but the early inhibition by gentle Skin Stimulation is decreased because of reduced responses of Aδ- and C-LTMs
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gentle mechanical Skin Stimulation inhibits micturition contractions via the spinal opioidergic system and by decreasing both ascending and descending transmissions of the micturition reflex in the spinal cord
PLOS ONE, 2015Co-Authors: Harumi Hotta, Nobuhiro WatanabeAbstract:Recently, we found that gentle mechanical Skin Stimulation inhibits the micturition reflex in anesthetized rats. However, the central mechanisms underlying this inhibition have not been determined. This study aimed to clarify the central neural mechanisms underlying this inhibitory effect. In urethane-anesthetized rats, cutaneous stimuli were applied for 1 min to the Skin of the perineum using an elastic polymer roller with a smooth, soft surface. Inhibition of rhythmic micturition contractions by perineal Stimulation was abolished by naloxone, an antagonist of opioidergic receptors, administered into the intrathecal space of the lumbosacral spinal cord at doses of 2–20 μg but was not affected by the same doses of naloxone administered into the subarachnoid space of the cisterna magna. Next, we examined whether perineal rolling Stimulation inhibited the descending and ascending limbs of the micturition reflex. Perineal rolling Stimulation inhibited bladder contractions induced by electrical Stimulation of the pontine micturition center (PMC) or the descending tract of the micturition reflex pathway. It also inhibited the bladder distension-induced increase in the blood flow of the dorsal cord at L5–S1, reflecting the neural activity of this area, as well as pelvic afferent-evoked field potentials in the dorsal commissure at the lumbosacral level; these areas contain long ascending neurons to the PMC. Neuronal activities in this center were also inhibited by the rolling Stimulation. These results suggest that the perineal rolling Stimulation activates the spinal opioidergic system and inhibits both ascending and descending transmissions of the micturition reflex pathway in the spinal cord. These inhibitions would lead to the shutting down of positive feedback between the bladder and the PMC, resulting in inhibition of the micturition reflex. Based on the central neural mechanisms we show here, gentle perineal Stimulation may be applicable to several different types of overactive bladder.
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Non-noxious Skin Stimulation activates the nucleus basalis of Meynert and promotes NGF secretion in the parietal cortex via nicotinic ACh receptors
The Journal of Physiological Sciences, 2014Co-Authors: Harumi Hotta, Nobuhiro Watanabe, Mathieu Piché, Sanae Hara, Takashi Yokawa, Sae UchidaAbstract:The effects of non-noxious Skin Stimulation on nerve growth factor (NGF) secretion in the parietal cortex were examined in anesthetized rats. Innocuous Skin Stimulation was delivered to the left hindlimb with a soft-hair brush. Extracellular NGF in the right parietal cortex was collected by microdialysis methods using a protein-permeable probe and was measured using an enzyme-linked immune-sorbent assay. Brushing produced a significant increase in extracellular NGF levels. This NGF response was not observed in rats pretreated with a nicotinic ACh receptor (nAChR) antagonist mecamylamine. We further examined whether brushing could activate the basal forebrain nucleus (nucleus basalis of Meynert, NBM), which is the main source of cholinergic fibers in the cerebral cortex, by means of functional MRI. The blood oxygen level-dependent signal in the right NBM was significantly higher during brushing compared to baseline. The results suggest that non-noxious Skin Stimulation activates NBM and promotes NGF secretion in the parietal cortex via nAChRs.
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A gentle mechanical Skin Stimulation technique for inhibition of micturition contractions of the urinary bladder.
Autonomic neuroscience : basic & clinical, 2011Co-Authors: Harumi Hotta, Nobuhiro Watanabe, Koichi Masunaga, Shogo Miyazaki, Yutaka KasuyaAbstract:Effects of gentle Skin Stimulation of various segmental areas on the micturition contractions of the urinary bladder were examined in anesthetized male rats. The bladder was expanded by infusing saline via urethral cannula until the bladder produced rhythmic micturition contractions as a consequence of rhythmic burst discharges of vesical pelvic efferent nerves. Gentle Stimulation was applied for 1 min by slowly rolling on top of Skin with an elastomer "roller". Rolling on the perineal area inhibited both micturition contractions and pelvic efferent discharges during and after Stimulation. Stimulation of the hindlimb, abdomen and forelimb inhibited micturition contractions after Stimulation ended, in this order of effectiveness. During Stimulation of the perineal Skin, the reflex increase in pelvic efferent discharges in response to bladder distension to a constant pressure was also inhibited up to 45% of its control response. The inhibition of the micturition contractions induced by perineal Stimulation was abolished, to a large extent by the opioid receptor antagonist naloxone and completely by severing cutaneous nerves innervating the perineal Skin. We recorded unitary afferent activity from cutaneous branches of the pudendal nerve and found that the fibers excited by Stimulation were low-threshold mechanoreceptive Aβ, Aδ and C fibers. Discharge rates of afferent C fibers (7.9 Hz) were significantly higher than those of Aβ (2.2 Hz) and Aδ (2.9 Hz) afferents. The results suggest that low frequency excitation of low threshold cutaneous mechanoreceptive myelinated and unmyelinated fibers inhibits a vesico-pelvic parasympathetic reflex, mainly via release of opioids, leading to inhibition of micturition contraction.
Harumi Hotta - One of the best experts on this subject based on the ideXlab platform.
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Gentle Perineal Skin Stimulation for Control of Nocturia.
Anatomical record (Hoboken N.J. : 2007), 2019Co-Authors: Harumi Hotta, Nobuhiro WatanabeAbstract:One of the major causes of nocturia is overactive bladder (OAB). Somatic afferent nerve stimuli are used for treating OAB. However, clinical evidence for the efficacy of this treatment is insufficient due to the lack of appropriate control stimuli. Studies on anesthetized animals, which eliminate emotional factors and placebo effects, have demonstrated an influence of somatic stimuli on urinary bladder functions and elucidated the underlying mechanisms. In general, the effects of somatic stimuli are dependent on the modality, location, and physical characteristics of the stimulus. Recently we showed that gentle stimuli applied to the perineal Skin using a soft elastomer roller inhibited micturition contractions to a greater extent than a roller with a hard surface. Studies aiming to elucidate the neural mechanisms of gentle Stimulation-induced inhibition reported that 1-10 Hz discharges of low-threshold cutaneous mechanoreceptive Aβ, Aδ, and C fibers evoked during Stimulation with an elastomer roller inhibited the micturition reflex by activating the spinal cord opioid system, thereby reducing both ascending and descending transmission between bladder and pontine micturition center. The present review will provide a brief summary of (1) the effect of somatic electrical Stimulation on the micturition reflex, (2) the effect of gentle mechanical Skin Stimulation on the micturition reflex, (3) the afferent, efferent, and central mechanisms underlying the effects of gentle Stimulation, and (4) a translational clinical study demonstrating the efficacy of gentle Skin stimuli for treating nocturia in the elderly with OAB by using the two roller types inducing distinct effects on rat micturition contractions. Anat Rec, 302:1824-1836, 2019. © 2019 American Association for Anatomy.
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Age-Related Changes in Neuromodulatory Control of Bladder Micturition Contractions Originating in the Skin
Frontiers Media S.A., 2018Co-Authors: Harumi Hotta, Harue Suzuki, Kaori Iimura, Nobuhiro WatanabeAbstract:The brainstem is essential for producing micturition contractions of the urinary bladder. Afferent input from perineal Skin evoked by gentle mechanical Stimulation inhibits micturition contractions by decreasing both ascending and descending transmissions between the brainstem and spinal cord. Dysfunction of this inhibitory mechanism may be one cause of the increase in the prevalence of overactive bladder in old age. The aim of this study was to examine effect of aging on function of Skin afferent fibers that inhibit bladder micturition contractions in rats. We used anesthetized male rats in three different age groups: young adult (4–5 months old), middle aged (6–9 months old), and aged (27–30 months old). The bladder was expanded to produce isovolumetric rhythmic micturition contractions. Skin afferent fibers were activated for 1 min either by electrical Stimulation (0.5 ms, 0.2–10 V, 0.1–10 Hz) of the cutaneous branch of the pudendal nerve (CBPN) or by gentle mechanical Skin Stimulation with an elastomer roller. When Skin afferent nerves were activated electrically, micturition contractions were inhibited in a similar manner in all age groups, with long latency inhibition induced by excitation of Aβ fibers and short latency inhibition by additional Aδ and C fiber excitation (at 1–10 Hz). On the contrary, when Skin afferent nerves were activated mechanically by rolling, latency of inhibition following rolling Stimulation was prolonged in aged rats. Single unitary afferent nerve activity of low-threshold mechanoreceptors (LTMs) from the cutaneous nerve was recorded. The discharge rate during rolling was not significantly reduced in Aβ units but was much lower in Aδ and C units in aged rats (0.4 and 0.5 Hz, respectively) than in young adult rats (3 and 7 Hz). These results suggest that the neural mechanism that inhibits bladder micturition contractions by Skin afferent input is well maintained in old age, but the early inhibition by gentle Skin Stimulation is decreased because of reduced responses of Aδ- and C-LTMs
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gentle mechanical Skin Stimulation inhibits micturition contractions via the spinal opioidergic system and by decreasing both ascending and descending transmissions of the micturition reflex in the spinal cord
PLOS ONE, 2015Co-Authors: Harumi Hotta, Nobuhiro WatanabeAbstract:Recently, we found that gentle mechanical Skin Stimulation inhibits the micturition reflex in anesthetized rats. However, the central mechanisms underlying this inhibition have not been determined. This study aimed to clarify the central neural mechanisms underlying this inhibitory effect. In urethane-anesthetized rats, cutaneous stimuli were applied for 1 min to the Skin of the perineum using an elastic polymer roller with a smooth, soft surface. Inhibition of rhythmic micturition contractions by perineal Stimulation was abolished by naloxone, an antagonist of opioidergic receptors, administered into the intrathecal space of the lumbosacral spinal cord at doses of 2–20 μg but was not affected by the same doses of naloxone administered into the subarachnoid space of the cisterna magna. Next, we examined whether perineal rolling Stimulation inhibited the descending and ascending limbs of the micturition reflex. Perineal rolling Stimulation inhibited bladder contractions induced by electrical Stimulation of the pontine micturition center (PMC) or the descending tract of the micturition reflex pathway. It also inhibited the bladder distension-induced increase in the blood flow of the dorsal cord at L5–S1, reflecting the neural activity of this area, as well as pelvic afferent-evoked field potentials in the dorsal commissure at the lumbosacral level; these areas contain long ascending neurons to the PMC. Neuronal activities in this center were also inhibited by the rolling Stimulation. These results suggest that the perineal rolling Stimulation activates the spinal opioidergic system and inhibits both ascending and descending transmissions of the micturition reflex pathway in the spinal cord. These inhibitions would lead to the shutting down of positive feedback between the bladder and the PMC, resulting in inhibition of the micturition reflex. Based on the central neural mechanisms we show here, gentle perineal Stimulation may be applicable to several different types of overactive bladder.
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Non-noxious Skin Stimulation activates the nucleus basalis of Meynert and promotes NGF secretion in the parietal cortex via nicotinic ACh receptors
The Journal of Physiological Sciences, 2014Co-Authors: Harumi Hotta, Nobuhiro Watanabe, Mathieu Piché, Sanae Hara, Takashi Yokawa, Sae UchidaAbstract:The effects of non-noxious Skin Stimulation on nerve growth factor (NGF) secretion in the parietal cortex were examined in anesthetized rats. Innocuous Skin Stimulation was delivered to the left hindlimb with a soft-hair brush. Extracellular NGF in the right parietal cortex was collected by microdialysis methods using a protein-permeable probe and was measured using an enzyme-linked immune-sorbent assay. Brushing produced a significant increase in extracellular NGF levels. This NGF response was not observed in rats pretreated with a nicotinic ACh receptor (nAChR) antagonist mecamylamine. We further examined whether brushing could activate the basal forebrain nucleus (nucleus basalis of Meynert, NBM), which is the main source of cholinergic fibers in the cerebral cortex, by means of functional MRI. The blood oxygen level-dependent signal in the right NBM was significantly higher during brushing compared to baseline. The results suggest that non-noxious Skin Stimulation activates NBM and promotes NGF secretion in the parietal cortex via nAChRs.
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A gentle mechanical Skin Stimulation technique for inhibition of micturition contractions of the urinary bladder.
Autonomic neuroscience : basic & clinical, 2011Co-Authors: Harumi Hotta, Nobuhiro Watanabe, Koichi Masunaga, Shogo Miyazaki, Yutaka KasuyaAbstract:Effects of gentle Skin Stimulation of various segmental areas on the micturition contractions of the urinary bladder were examined in anesthetized male rats. The bladder was expanded by infusing saline via urethral cannula until the bladder produced rhythmic micturition contractions as a consequence of rhythmic burst discharges of vesical pelvic efferent nerves. Gentle Stimulation was applied for 1 min by slowly rolling on top of Skin with an elastomer "roller". Rolling on the perineal area inhibited both micturition contractions and pelvic efferent discharges during and after Stimulation. Stimulation of the hindlimb, abdomen and forelimb inhibited micturition contractions after Stimulation ended, in this order of effectiveness. During Stimulation of the perineal Skin, the reflex increase in pelvic efferent discharges in response to bladder distension to a constant pressure was also inhibited up to 45% of its control response. The inhibition of the micturition contractions induced by perineal Stimulation was abolished, to a large extent by the opioid receptor antagonist naloxone and completely by severing cutaneous nerves innervating the perineal Skin. We recorded unitary afferent activity from cutaneous branches of the pudendal nerve and found that the fibers excited by Stimulation were low-threshold mechanoreceptive Aβ, Aδ and C fibers. Discharge rates of afferent C fibers (7.9 Hz) were significantly higher than those of Aβ (2.2 Hz) and Aδ (2.9 Hz) afferents. The results suggest that low frequency excitation of low threshold cutaneous mechanoreceptive myelinated and unmyelinated fibers inhibits a vesico-pelvic parasympathetic reflex, mainly via release of opioids, leading to inhibition of micturition contraction.
Y. Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Attenuation of somatosensory evoked potentials by acupuncture and tactile Skin Stimulation in man
Brain Topography, 1991Co-Authors: Y. Kawashima, S. Toma, Y. NakajimaAbstract:The effects of acupuncture and tactile Skin Stimulation on somatosensory evoked potentials (SEPs), elicited by the median nerve Stimulation, were investigated in healthy subjects. Acupuncture needles were inserted into either Hegu plus Shousanli, Hegu plus Waiguan, or Shousanli positions ipsilateral to the median nerve Stimulation. Tactile Skin Stimulation was applied to either the ulnar side of the palm, or the dorsal surface of the hand or forearm ipsilaterally to the nerve Stimulation. It was found that acupuncture significantly suppressed the amplitude of P22 and P40, and that the tactile Skin Stimulation of the ulnar side of the palm significantly suppressed the amplitude of P22 and P40, but that the peak latencies were not affected. Dipole tracing analysis showed that the location and vector direction of P22 were not changed but the vector moment of P22 was changed by both acupuncture and tactile Stimulation. Based on these findings the suppressive effect of acupuncture and Skin Stimulation on P22 was proposed to be due to the afferent inhibition in the somatosensory cortex. Although the suppressive mechanism of P40 by tactile Skin Stimulation seemed to be similar to that of P22, the suppression of P40 by acupuncture appeared to include different mechanisms.
Mark Tommerdahl - One of the best experts on this subject based on the ideXlab platform.
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nociceptive afferent activity alters the si ra neuron response to mechanical Skin Stimulation
Cerebral Cortex, 2010Co-Authors: B L Whitsel, Oleg V. Favorov, Jaekwang Lee, P M Quibrera, Mark TommerdahlAbstract:Procedures that reliably evoke cutaneous pain in humans (i.e., 5-7 s Skin contact with a 47-51 °C probe, intradermal algogen injection) are shown to decrease the mean spike firing rate (MFR) and degree to which the rapidly adapting (RA) neurons in areas 3b/1 of squirrel monkey primary somatosensory cortex (SI) entrain to a 25-Hz stimulus to the receptive field center (RF(center)) when stimulus amplitude is "near-threshold" (i.e., 10-50 μm). In contrast, RA neuron MFR and entrainment are either unaffected or enhanced by 47-51 °C contact or intradermal algogen injection when the amplitude of 25-Hz Stimulation is 100-200 μm (suprathreshold). The results are attributed to an "activity dependence" of γ-aminobutyric acid (GABA) action on the GABA(A) receptors of RA neurons. The nociceptive afferent drive triggered by Skin contact with a 47-51 °C probe or intradermal algogen is proposed to activate nociresponsive neurons in area 3a which, via corticocortical connections, leads to the release of GABA in areas 3b/1. It is hypothesized that GABA is hyperpolarizing/inhibitory and suppresses stimulus-evoked RA neuron MFR and entrainment whenever RA neuron activity is low (as when the RF(center) stimulus is weak/near-threshold) but is depolarizing/excitatory and augments MFR and entrainment when RA neuron activity is high (when the stimulus is strong/suprathreshold).
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Effects of high-frequency Skin Stimulation on SI cortex: mechanisms and functional implications.
Somatosensory & motor research, 2005Co-Authors: Mark Tommerdahl, Oleg V. Favorov, Barry L. WhitselAbstract:Optical intrinsic signal (OIS) imaging methods were used to record the responses of contralateral SI cortex to 25 Hz ("flutter") and also to 200 Hz ("vibration") Stimulation of the Skin. Anesthetized cats and squirrel monkeys were subjects. Separate series of experiments were carried out to evaluate the contralateral SI response to continuous, multisecond 25 Hz vs. 200 Hz Stimulation (a) at multiple Skin sites arranged along the proximal-distal axis of the fore- or hindlimb (Series I); (b) in the presence and absence of a ring placed in firm contact with the Skin surrounding the stimulus site (Series II); (c) before and after topical application of local anesthetic to the stimulus site (Series III); and, finally, (c) to continuous 25 Hz or 200 Hz Stimulation applied independently, and also concomitantly ("complex waveform Stimulation") to the same Skin site (Series IV). The principal findings are: (a) the relationship between the SI optical responses to 25 Hz vs. 200 Hz Stimulation of a Skin site varies systematically with position of the stimulus site on the limb-at a distal site both 25 Hz and 200 Hz Stimulation evoke a well-maintained increase in absorbance, and as the stimulus site is shifted proximally on the limb the response to 200 Hz, but not the response to 25 Hz Stimulation, converts to a frank decrease in absorbance; (b) placement of a ring about a Skin site at which in the absence of a ring 200 Hz Stimulation evoked a decrease in SI absorbance converts the response to 200 Hz to one consistent with increased SI RA neuronal activation (i.e., with the ring in place 200 Hz Stimulation evokes a change in SI absorbance approximating the response to 25 Hz Stimulation); (c) topical local anesthetic preferentially and reversibly decreases the magnitude of the absorbance increase associated with 25 Hz flutter Stimulation; and (d) complex waveform Stimulation consistently is associated with a smaller increase in absorbance than obtained with same-site 25 Hz Stimulation. Collectively, the findings are consistent with the idea that the Pacinian (PC) afferent activity which unavoidably accompanies cutaneous flutter Stimulation triggers CNS mechanisms that "funnel" (sharpen) the spatially distributed contralateral SI response to the flutter stimulus. Viewed in this context, the fact that a flutter stimulus unavoidably co-activates RA and PC afferents appears functionally beneficial because the CNS mechanisms activated by PC afferent drive modify the SI response to Skin flutter in a manner predicted to enable more accurate perceptual localization than would be possible if the flutter stimulus only activated RA afferents.
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RESPONSE OF ANTERIOR PARIETAL CORTEX TO DIFFERENT MODES OF SAME-SITE Skin Stimulation
Journal of neurophysiology, 1998Co-Authors: Mark Tommerdahl, K. A. Delemos, Oleg V. Favorov, C. B. Metz, Charles J. Vierck, Barry L. WhitselAbstract:Tommerdahl, M., K. A. Delemos, O. V. Favorov, C. B. Metz, C. J. Viereck, Jr., and B. L. Whitsel. Response of anterior parietal cortex to different modes of same-site Skin Stimulation. J. Neurophysi...
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Effects of Spinal Dorsal Column Transection on the Response of Monkey Anterior Parietal Cortex to Repetitive Skin Stimulation
Cerebral cortex (New York N.Y. : 1991), 1996Co-Authors: Mark Tommerdahl, Oleg V. Favorov, C. B. Metz, Charles J. Vierck, Barry L. Whitsel, Sharon L. Juliano, B. Cooper, B. NakhleAbstract:The pattern of 14C-2-deoxyglucose (2DG) labeling in anterior parietal cortex was evaluated in three groups of experimental subjects: (1) subjects in which all spinal pathways projecting at short latency to the contralateral hemisphere were intact, (2) subjects with either unilateral or bilateral transection of the dorsal column pathway, and (3) subjects in whom a two-stage tractotomy (dorsal column isolation) restricted short-latency mechanoreceptor drive to that conveyed via the dorsal column pathway. Macaca fascicularis and Macaca arctoides monkeys were studied. When the spinal cord pathways projecting at short latency to contralateral anterior parietal cortex were intact, controlled vibrotactile or Skin brushing stimuli evoked one or, more rarely, several loci of maximal 2DG uptake (typically 1.5-2.5 mm in diameter) in the topographically appropriate location(s) within area 3b and/or area 1. The labeling at each locus of maximal 2DG uptake extended continuously across layers II-VI. Each locus of maximal 2DG uptake was bordered on one or more sides by irregularly shaped zones of below-background 2DG uptake that could extend without interruption from area 3b into area 3a, and/or from area 1 into area 2. In the absence of Skin Stimulation, little or no above-background 2DG uptake occurred at any locus within areas 3b and 1 of subjects in which the dorsal column pathway on the opposite side of the spinal cord was intact. In subjects with a complete transection of the spinal dorsal column the global 2DG pattern evoked by a repetitive Skin stimulus in contralateral anterior parietal cortex was a near mirror image of the pattern evoked by the same stimulus in intact subjects. In the absence of the dorsal column path, neither 10-25 Hz vibrotactile nor brushing Stimulation evoked above-background uptake at the topographically appropriate location(s) within contralateral area 3b and/or area 1. Instead, a prominent region of below-background 2DG uptake occupied the topographically appropriate location in area 3b and/or area 1, and the region of suppressed 2DG uptake was bounded by one or more regions of above-background 2DG uptake that extended from areas 3b or 1 into area 3a and/or into area 2. When a two-stage spinal tractotomy prevented stimulus-evoked short-latency input from reaching contralateral anterior parietal cortex via pathways other than the dorsal column, the 2DG activity patterns evoked in contralateral cortex by either brushing or vibrotactile stimuli were similar to the patterns obtained when the somatosensory pathways on the opposite side of the spinal cord were intact. A neural network model was developed to evaluate the hypothesis that the observed cortical effects of dorsal column transection might be attributable, at least in part, to inhibitory interactions among anterior parietal cortical regions that receive their principal input from different spinal cord pathways. The model incorporated known features of (1) the cortical projection of spinal somatosensory pathways, (2) anterior parietal intrinsic and long-distance horizontal connectivity, and (3) certain neurotransmitter/receptor systems characteristic of sensory neocortex. Simulations of the model network provided results consistent with the idea that repetitive Skin stimuli evoke maladaptive, time-dependent corticocortical interactions within anterior parietal cortex contralateral to a dorsal column lesion. The observations indicate that corticocortical interactions account for the (1) near mirror-image pattern (relative to the normal Mexican hat-like pattern) of anterior parietal stimulus-evoked 2DG uptake observed in subjects with a dorsal column lesion, (2) unusual time-dependent response properties of individual area 3b and 1 neurons or neuron populations deprived of dorsal column input (Dreyer et al., 1974; Vierck et al., 1990a; Makous and Vierck, 1994), and (3) abnormal time-dependent characteristics of tactile perception in monkeys with dorsal colum
Y. Kawashima - One of the best experts on this subject based on the ideXlab platform.
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Attenuation of somatosensory evoked potentials by acupuncture and tactile Skin Stimulation in man
Brain Topography, 1991Co-Authors: Y. Kawashima, S. Toma, Y. NakajimaAbstract:The effects of acupuncture and tactile Skin Stimulation on somatosensory evoked potentials (SEPs), elicited by the median nerve Stimulation, were investigated in healthy subjects. Acupuncture needles were inserted into either Hegu plus Shousanli, Hegu plus Waiguan, or Shousanli positions ipsilateral to the median nerve Stimulation. Tactile Skin Stimulation was applied to either the ulnar side of the palm, or the dorsal surface of the hand or forearm ipsilaterally to the nerve Stimulation. It was found that acupuncture significantly suppressed the amplitude of P22 and P40, and that the tactile Skin Stimulation of the ulnar side of the palm significantly suppressed the amplitude of P22 and P40, but that the peak latencies were not affected. Dipole tracing analysis showed that the location and vector direction of P22 were not changed but the vector moment of P22 was changed by both acupuncture and tactile Stimulation. Based on these findings the suppressive effect of acupuncture and Skin Stimulation on P22 was proposed to be due to the afferent inhibition in the somatosensory cortex. Although the suppressive mechanism of P40 by tactile Skin Stimulation seemed to be similar to that of P22, the suppression of P40 by acupuncture appeared to include different mechanisms.