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Sample records for additional somatosensory contact

  1. Microglia contact induces synapse formation in developing somatosensory cortex

    PubMed Central

    Miyamoto, Akiko; Wake, Hiroaki; Ishikawa, Ayako Wendy; Eto, Kei; Shibata, Keisuke; Murakoshi, Hideji; Koizumi, Schuichi; Moorhouse, Andrew J.; Yoshimura, Yumiko; Nabekura, Junichi

    2016-01-01

    Microglia are the immune cells of the central nervous system that play important roles in brain pathologies. Microglia also help shape neuronal circuits during development, via phagocytosing weak synapses and regulating neurogenesis. Using in vivo multiphoton imaging of layer 2/3 pyramidal neurons in the developing somatosensory cortex, we demonstrate here that microglial contact with dendrites directly induces filopodia formation. This filopodia formation occurs only around postnatal day 8–10, a period of intense synaptogenesis and when microglia have an activated phenotype. Filopodia formation is preceded by contact-induced Ca2+ transients and actin accumulation. Inhibition of microglia by genetic ablation decreases subsequent spine density, functional excitatory synapses and reduces the relative connectivity from layer 4 neurons. Our data provide the direct demonstration of microglial-induced spine formation and provide further insights into immune system regulation of neuronal circuit development, with potential implications for developmental disorders of immune and brain dysfunction. PMID:27558646

  2. [Allergic contact dermatitis as a consequence of additional occupations].

    PubMed

    Paravina, M; Stanojević, M; Spalević, Lj; Jovanović, D

    1994-01-01

    During discovering etiology of allergic contact dermatitis (ACD) anamnesis is of great importance (date of life, profession of a patients, activities besides the profession, habits, hobbies). Many people have additional professions, habits, hobbies). Many people have additional professions, either as hobbies or as financial reasons. They can show senzibilization to substances they come to contact with. The aim of this work is to point to this possibility of generating ACD. Five petients suffering from ACD were presented. All of them were tested by standard series and by substances thej came to contact with, while going in for additional occupations. 1. A metalsmith, going in for beekeeping, had positive tests to propolis and balsam of Peru. 2. A construction worker growing fruit, hat positive tests to TMT and fingicid melpreks. 3. Stics weaver, engaging in constructions work, had positive tests to potassium bichromate. 4. Retired professor in matematics, engaged in constructions works, had positive tests to potassium bichromate, too. 5. A law student, going in for photography, had positive tests to colour film developer. The nature of allergens, length of exposure, possibilites for elimination of allergens, means of protection etc have been discussed. It was conslused that a detail examination of patients was necessary for proving causes of ACD.

  3. Hydrophobins as aqueous lubricant additive for a soft sliding contact.

    PubMed

    Lee, Seunghwan; Røn, Troels; Pakkanen, Kirsi I; Linder, Markus

    2015-01-01

    Two type II fungal hydrophobins, HFBI and FpHYD5, have been studied as aqueous lubricant additive at a nonpolar, compliant sliding contact (self-mated poly(dimethylsiloxane) (PDMS) contact) at two different concentrations, 0.1 mg/mL and 1.0 mg/mL. The two hydrophobins are featured as non-glycosylated (HFBI, m.w. ca. 7 kDa) vs glycosylated (FpHYD5, m.w. ca. 10 kDa) proteins. Far UV CD spectra of the two hydrophobins were very similar, suggesting overall structural similarity, but showed a noticeable difference according to the concentration. This is proposed to be related to the formation of multimers at 1.0 mg/mL. Despite 10-fold difference in the bulk concentration, the adsorbed masses of the hydrophobins onto PDMS surface obtained from the two solutions (0.1 and 1.0 mg/mL) were nearly identical, suggesting that a monolayer of the hydrophobins are formed from 0.1 mg/mL solution. PDMS-PDMS sliding interface was effectively lubricated by the hydrophobin solutions, and showed a reduction in the coefficient of friction by as much as ca. two orders of magnitude. Higher concentration solution (1.0 mg/mL) provided a superior lubrication, particularly in low-speed regime, where boundary lubrication characteristic is dominant via 'self-healing' mechanism. FpHYD5 revealed a better lubrication than HFBI presumably due to the presence of glycans and improved hydration of the sliding interface. Two type II hydrophobins function more favorably compared to a synthetic amphiphilic copolymer, PEO-PPO-PEO, with a similar molecular weight. This is ascribed to higher amount of adsorption of the hydrophobins to hydrophobic surfaces from aqueous solution. PMID:25466456

  4. Hypergravity exposure decreases gamma-aminobutyric acid immunoreactivity in axon terminals contacting pyramidal cells in the rat somatosensory cortex: a quantitative immunocytochemical image analysis

    NASA Technical Reports Server (NTRS)

    D'Amelio, F.; Wu, L. C.; Fox, R. A.; Daunton, N. G.; Corcoran, M. L.; Polyakov, I.

    1998-01-01

    Quantitative evaluation of gamma-aminobutyric acid immunoreactivity (GABA-IR) in the hindlimb representation of the rat somatosensory cortex after 14 days of exposure to hypergravity (hyper-G) was conducted by using computer-assisted image processing. The area of GABA-IR axosomatic terminals apposed to pyramidal cells of cortical layer V was reduced in rats exposed to hyper-G compared with control rats, which were exposed either to rotation alone or to vivarium conditions. Based on previous immunocytochemical and behavioral studies, we suggest that this reduction is due to changes in sensory feedback information from muscle receptors. Consequently, priorities for muscle recruitment are altered at the cortical level, and a new pattern of muscle activity is thus generated. It is proposed that the reduction observed in GABA-IR of the terminal area around pyramidal neurons is the immunocytochemical expression of changes in the activity of GABAergic cells that participate in reprogramming motor outputs to achieve effective movement control in response to alterations in the afferent information.

  5. Subliminal stimulation and somatosensory signal detection.

    PubMed

    Ferrè, Elisa Raffaella; Sahani, Maneesh; Haggard, Patrick

    2016-10-01

    Only a small fraction of sensory signals is consciously perceived. The brain's perceptual systems may include mechanisms of feedforward inhibition that protect the cortex from subliminal noise, thus reserving cortical capacity and conscious awareness for significant stimuli. Here we provide a new view of these mechanisms based on signal detection theory, and gain control. We demonstrated that subliminal somatosensory stimulation decreased sensitivity for the detection of a subsequent somatosensory input, largely due to increased false alarm rates. By delivering the subliminal somatosensory stimulus and the to-be-detected somatosensory stimulus to different digits of the same hand, we show that this effect spreads across the sensory surface. In addition, subliminal somatosensory stimulation tended to produce an increased probability of responding "yes", whether the somatosensory stimulus was present or not. Our results suggest that subliminal stimuli temporarily reduce input gain, avoiding excessive responses to further small inputs. This gain control may be automatic, and may precede discriminative classification of inputs into signals or noise. Crucially, we found that subliminal inputs influenced false alarm rates only on blocks where the to-be-detected stimuli were present, and not on pre-test control blocks where they were absent. Participants appeared to adjust their perceptual criterion according to a statistical distribution of stimuli in the current context, with the presence of supraliminal stimuli having an important role in the criterion-setting process. These findings clarify the cognitive mechanisms that reserve conscious perception for salient and important signals.

  6. Subliminal stimulation and somatosensory signal detection.

    PubMed

    Ferrè, Elisa Raffaella; Sahani, Maneesh; Haggard, Patrick

    2016-10-01

    Only a small fraction of sensory signals is consciously perceived. The brain's perceptual systems may include mechanisms of feedforward inhibition that protect the cortex from subliminal noise, thus reserving cortical capacity and conscious awareness for significant stimuli. Here we provide a new view of these mechanisms based on signal detection theory, and gain control. We demonstrated that subliminal somatosensory stimulation decreased sensitivity for the detection of a subsequent somatosensory input, largely due to increased false alarm rates. By delivering the subliminal somatosensory stimulus and the to-be-detected somatosensory stimulus to different digits of the same hand, we show that this effect spreads across the sensory surface. In addition, subliminal somatosensory stimulation tended to produce an increased probability of responding "yes", whether the somatosensory stimulus was present or not. Our results suggest that subliminal stimuli temporarily reduce input gain, avoiding excessive responses to further small inputs. This gain control may be automatic, and may precede discriminative classification of inputs into signals or noise. Crucially, we found that subliminal inputs influenced false alarm rates only on blocks where the to-be-detected stimuli were present, and not on pre-test control blocks where they were absent. Participants appeared to adjust their perceptual criterion according to a statistical distribution of stimuli in the current context, with the presence of supraliminal stimuli having an important role in the criterion-setting process. These findings clarify the cognitive mechanisms that reserve conscious perception for salient and important signals. PMID:27387873

  7. Contact pair correlation functions and equation of state for additive hard disk fluid mixtures

    NASA Astrophysics Data System (ADS)

    Barrio, C.; Solana, J. R.

    2001-10-01

    The contact pair correlation functions and the equation of state for a binary mixture of additive hard disks is obtained using a procedure similar to that leading to the Boublı´k-Mansoori-Carnahan-Starling-Leland equation of state for mixtures of additive hard spheres. The results from the derived equations are tested against new Monte Carlo data obtained for several diameter ratios and mole fractions. The overall agreement is excellent. The equation of state reproduces exactly the second virial coefficient of the mixture and the third with great accuracy. Predicted values of the fourth and fifth virial coefficients are also in very good agreement with numerical data.

  8. Contact pair correlation functions of binary mixtures of additive hard spheres from the virial expansion

    NASA Astrophysics Data System (ADS)

    Barrio, C.; Solana, J. R.

    2003-08-01

    Density expansions of the contact pair correlation functions for binary mixtures of additive hard spheres are obtained from the virial expansion of the equation of state. The procedure is based on the use consistency conditions. The resulting expansions are exact up to first order in the density. This corresponds to the third virial coefficient which is exactly known for these mixtures. Analytical expressions for the second and third order terms are obtained on the basis of very accurate approximate analytical expressions for the fourth and fifth virial coefficients. It is found that the series converge slowly, but the convergency can be accelerated by means of a resummation procedure.

  9. Novel composite plastics containing silver(I) acylpyrazolonato additives display potent antimicrobial activity by contact.

    PubMed

    Marchetti, Fabio; Palmucci, Jessica; Pettinari, Claudio; Pettinari, Riccardo; Condello, Francesca; Ferraro, Stefano; Marangoni, Mirko; Crispini, Alessandra; Scuri, Stefania; Grappasonni, Iolanda; Cocchioni, Mario; Nabissi, Massimo; Chierotti, Michele R; Gobetto, Roberto

    2015-01-01

    New silver(I) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution NMR spectroscopy, solid-state IR and NMR spectroscopies, and X-ray diffraction techniques. These derivatives have been embedded in polyethylene (PE) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains (E. coli, P. aeruginosa, and S. aureus): Most of the composites show antimicrobial action comparable to PE embedded with AgNO3 . Tests by contact and release tests for specific migration of silver from PE composites clearly indicate that, at least in the case of the PE, for composites containing polynuclear silver(I) additives, the antimicrobial action is exerted by contact, without release of silver ions. Moreover, PE composites can be re-used several times, displaying the same antimicrobial activity. Membrane permeabilization studies and induced reactive oxygen species (ROS) generation tests confirm the disorganization of bacterial cell membranes. The cytotoxic effect, evaluated in CD34(+) cells by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazoliumbromide) and CFU (colony forming units) assays, indicates that the PE composites do not induce cytotoxicity in human cells. Studies of ecotoxicity, based on the test of Daphnia magna, confirm tolerability of the PE composites by higher organisms and exclude the release of Ag(+) ions in sufficient amounts to affect water environment.

  10. Pial arteries respond earlier than penetrating arterioles to neural activation in the somatosensory cortex in awake mice exposed to chronic hypoxia: an additional mechanism to proximal integration signaling?

    PubMed Central

    Sekiguchi, Yuta; Takuwa, Hiroyuki; Kawaguchi, Hiroshi; Kikuchi, Takahiro; Okada, Eiji; Kanno, Iwao; Ito, Hiroshi; Tomita, Yutaka; Itoh, Yoshiaki; Suzuki, Norihiro; Sudo, Ryo; Tanishita, Kazuo; Masamoto, Kazuto

    2014-01-01

    The pial and penetrating arteries have a crucial role in regulating cerebral blood flow (CBF) to meet neural demand in the cortex. Here, we examined the longitudinal effects of chronic hypoxia on the arterial diameter responses to single whisker stimulation in the awake mouse cortex, where activity-induced responses of CBF were gradually attenuated. The vasodilation responses to whisker stimulation under prehypoxia normal conditions were 8.1% and 12% relative to their baselines in the pial arteries and penetrating arterioles, respectively. After 3 weeks of hypoxia, however, these responses were significantly reduced to 5.5% and 4.1%, respectively. The CBF response, measured using laser-Doppler flowmetry (LDF), induced by the same whisker stimulation was also attenuated (14% to 2.6%). A close linear correlation was found for the responses between the penetrating arteriolar diameter and LDF, and their temporal dynamics. After 3 weeks of chronic hypoxia, the initiation of vasodilation in the penetrating arterioles was significantly extended, but the pial artery responses remained unchanged. These results show that vasodilation of the penetrating arterioles followed the pial artery responses, which are not explainable in terms of proximal integration signaling. The findings therefore indicate an additional mechanism for triggering pial artery dilation in the neurovascular coupling. PMID:25074744

  11. The influence of small impurity additions and direct electric current on the kinetics of contact melting in metals

    NASA Astrophysics Data System (ADS)

    Ahkubekov, A. A.; Ahkubekova, S. N.; Enaldieva, O. L.; Orkvasov, T. A.; Sozaev, V. A.

    2008-02-01

    Using the experimental data on contact melting of polycrystalline indium, tin and lead - based solid solutions with low-melting alloys we show that besides the diffusive, adhesive and low - dimensional mechanisms of contact melting it is necessary to take into account the segregational mechanism as well. The surfaces of a contact between the polycrystalline solid solutions and low - melting metals enrich in lower melting components due to the grain-boundary and surface segregation. One can influence on the kinetics of contact melting using alkali metals as impurity additives and applying the direct electric current. For example, the sodium addition to indium results in 3 times expansion of contact layer in the (In + 0.1 at. % Na) - Bi system, but in 2 times shrinking of that layer in the (In + 0.1 at. % Na) - Cd system in comparison to experiments without impurities.

  12. Tuning the Receding Contact Angle on Hydrogels by Addition of Particles.

    PubMed

    Boulogne, François; Ingremeau, François; Limat, Laurent; Stone, Howard A

    2016-06-01

    Control of the swelling, chemical functionalization, and adhesivity of hydrogels are finding new applications in a wide range of material systems. We investigate experimentally the effect of adsorbed particles on hydrogels on the depinning of contact lines. In our experiments, a water drop containing polystyrene microspheres is deposited on a swelling hydrogel, which leads to the drop absorption and particle deposition. Two regimes are observed: a decreasing drop height with a pinned contact line followed by a receding contact line. We show that increasing the particles concentration increases the duration of the first regime and significantly decreases the total absorption time. The adsorbed particles increase the pinning force at the contact line. Finally, we develop a method to measure the receding contact angle with the consideration of the hydrogel swelling. PMID:27185647

  13. Coupling of fingertip somatosensory information to head and body sway

    NASA Technical Reports Server (NTRS)

    Jeka, J. J.; Schoner, G.; Dijkstra, T.; Ribeiro, P.; Lackner, J. R.

    1997-01-01

    Light touch contact of a fingertip with a stationary surface can provide orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip provide sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, we asked to which extent somatosensory cues are part of the postural control system, that is, which sensory signal supports this coupling? We investigated postural control not only when the contact surface was stationary, but also when it was moving rhythmically (from 0.1 to 0.5 Hz). In doing so, we brought somatosensory cues from the hand into conflict with other parts of the postural control system. Our focus was the temporal relationship between body sway and the contact surface. Postural sway was highly coherent with contact surface motion. Head and body sway assumed the frequency of the moving contact surface at all test frequencies. To account for these results, a simple model was formulated by approximating the postural control system as a second-order linear dynamical system. The influence of the touch stimulus was captured as the difference between the velocity of the contact surface and the velocity of body sway, multiplied by a coupling constant. Comparison of empirical results (relative phase, coherence, and gain) with model predictions supports the hypothesis of coupling between body sway and touch cues through the velocity of the somatosensory stimulus at the fingertip. One subject, who perceived movement of the touch surface, demonstrated weaker coupling than other subjects, suggesting that cognitive mechanisms introduce flexibility into the postural control scheme.

  14. The somatosensory evoked magnetic fields.

    PubMed

    Kakigi, R; Hoshiyama, M; Shimojo, M; Naka, D; Yamasaki, H; Watanabe, S; Xiang, J; Maeda, K; Lam, K; Itomi, K; Nakamura, A

    2000-08-01

    Averaged magnetoencephalography (MEG) following somatosensory stimulation, somatosensory evoked magnetic field(s) (SEF), in humans are reviewed. The equivalent current dipole(s) (ECD) of the primary and the following middle-latency components of SEF following electrical stimulation within 80-100 ms are estimated in area 3b of the primary somatosensory cortex (SI), the posterior bank of the central sulcus, in the hemisphere contralateral to the stimulated site. Their sites are generally compatible with the homunculus which was reported by Penfield using direct cortical stimulation during surgery. SEF to passive finger movement is generated in area 3a or 2 of SI, unlike with electrical stimulation. Long-latency components with peaks of approximately 80-120 ms are recorded in the bilateral hemispheres and their ECD are estimated in the secondary somatosensory cortex (SII) in the bilateral hemispheres. We also summarized (1) the gating effects on SEF by interference tactile stimulation or movement applied to the stimulus site, (2) clinical applications of SEF in the fields of neurosurgery and neurology and (3) cortical plasticity (reorganization) of the SI. SEF specific to painful stimulation is also recorded following painful stimulation by CO(2) laser beam. Pain-specific components are recorded over 150 ms after the stimulus and their ECD are estimated in the bilateral SII and the limbic system. We introduced a newly-developed multi (12)-channel gradiometer system with the smallest and highest quality superconducting quantum interference device (micro-SQUID) available to non-invasively detect the magnetic fields of a human peripheral nerve. Clear nerve action fields (NAFs) were consistently recorded from all subjects.

  15. Additional Evaluation of the Point-of-Contact Circulating Cathodic Antigen Assay for Schistosoma mansoni Infection

    PubMed Central

    Mwinzi, Pauline N. M.; Kittur, Nupur; Ochola, Elizabeth; Cooper, Philip J.; Campbell, Carl H.; King, Charles H.; Colley, Daniel G.

    2015-01-01

    Studies of the urine-based point-of-contact cathodic circulating antigen test (POC-CCA) in Schistosoma mansoni-endemic settings in Africa indicate it has good sensitivity in detecting infections, but in areas of low prevalence, the POC-CCA can be positive for persons who are egg-negative by Kato-Katz stool assays. We examined the POC-CCA assay for: (a) batch-to-batch stability; (b) intra-reader and inter-reader variability; (c) day-to-day variability compared to Kato-Katz stool assays, and (d) to see if praziquantel (PZQ) treatment converted Kato-Katz-negative/POC-CCA positive individuals to POC-CCA negativity. We found essentially no batch-to-batch variation, negligible intra-reader variability (2%), and substantial agreement for inter-reader reliability. Some day-to-day variation was observed over 5 days of urine collection, but less than the variation in Kato-Katz stool assays over 3 days. To evaluate the effect of treatment on Kato-Katz(−)/POC-CCA(+) children, 149 children in an area of 10–15% prevalence who were Kato-Katz(−) based on 3 stool samples but POC-CCA(+) were enrolled. Seven days after treatment (PZQ 40 mg/kg) samples were again collected and tested. Almost half (47%) POC-CCA positive children turned negative. Those still POC-CCA positive received a second treatment, and 34% of them turned POC-CCA negative upon this second treatment. Most who remained POC-CCA positive shifted each time to a “lesser” POC-CCA “level of positivity.” The data suggest that most Kato-Katz-negative/POC-CCA positive individuals harbor low-intensity infections, and each treatment kills all or some of their adult worms. The data also suggest that when evaluated by a more sensitive assay, the effective cure rates for PZQ are significantly less than those inferred from fecal testing. These findings have public health significance for the mapping and monitoring of Schistosoma infections and in planning the transition from schistosomiasis morbidity control to

  16. [Antibacterial effect of food additives and detergents against histamine-producing bacteria on food contact material surfaces].

    PubMed

    Kamii, Eri; Terada, Gaku; Akiyama, Junki; Isshiki, Kenji

    2011-01-01

    We investigated the antibacterial activity of food additives and detergents against histamine-producing bacteria on food contact material surfaces. Based on minimum inhibitory concentration (MIC) testing with Morganella morganii NBRC3848, Raoultella planticola NBRC3317 and Enterobacter aerogenes NCTC10006, we screened nine food additives and four detergents with relatively high inhibitory potency. We prepared food contact material surfaces contaminated with histamine-producing bacteria, and dipped them into fourteen agents (100 µg/mL). Sodium hypochlorite, benzalkonium chloride, benzethonium chloride, n-hexadecyltrimethylammonium chloride and 1-n-hexadecylpyridinium chloride showed antibacterial activity against histamine-producing bacteria. We prepared low concentrations of the five agents (10 and 50 µg/mL) and tested them in the same way. Sodium hypochlorite showed high antibacterial activity at 10 µg/mL, and the other four showed activity at 50 µg/mL. So, washing the material surface with these reagents might be effective to prevent histamine food poisoning owing to bacterial contamination of food contact surfaces.

  17. Somatosensory integration controlled by dynamic thalamocortical feed-forward inhibition.

    PubMed

    Gabernet, Laetitia; Jadhav, Shantanu P; Feldman, Daniel E; Carandini, Matteo; Scanziani, Massimo

    2005-10-20

    The temporal features of tactile stimuli are faithfully represented by the activity of neurons in the somatosensory cortex. However, the cellular mechanisms that enable cortical neurons to report accurate temporal information are not known. Here, we show that in the rodent barrel cortex, the temporal window for integration of thalamic inputs is under the control of thalamocortical feed-forward inhibition and can vary from 1 to 10 ms. A single thalamic fiber can trigger feed-forward inhibition and contacts both excitatory and inhibitory cortical neurons. The dynamics of feed-forward inhibition exceed those of each individual synapse in the circuit and are captured by a simple disynaptic model of the thalamocortical projection. The variations in the integration window produce changes in the temporal precision of cortical responses to whisker stimulation. Hence, feed-forward inhibitory circuits, classically known to sharpen spatial contrast of tactile inputs, also increase the temporal resolution in the somatosensory cortex.

  18. Migration of fluorochemical paper additives from food-contact paper into foods and food simulants.

    PubMed

    Begley, T H; Hsu, W; Noonan, G; Diachenko, G

    2008-03-01

    Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water-ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg(-1) popcorn after popping and butter contained 0.1 mg kg(-1) after 40 days at 4 degrees C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper. PMID:18311629

  19. Impact of contacting study authors to obtain additional data for systematic reviews: diagnostic accuracy studies for hepatic fibrosis

    PubMed Central

    2014-01-01

    Background Seventeen of 172 included studies in a recent systematic review of blood tests for hepatic fibrosis or cirrhosis reported diagnostic accuracy results discordant from 2 × 2 tables, and 60 studies reported inadequate data to construct 2 × 2 tables. This study explores the yield of contacting authors of diagnostic accuracy studies and impact on the systematic review findings. Methods Sixty-six corresponding authors were sent letters requesting additional information or clarification of data from 77 studies. Data received from the authors were synthesized with data included in the previous review, and diagnostic accuracy sensitivities, specificities, and positive and likelihood ratios were recalculated. Results Of the 66 authors, 68% were successfully contacted and 42% provided additional data for 29 out of 77 studies (38%). All authors who provided data at all did so by the third emailed request (ten authors provided data after one request). Authors of more recent studies were more likely to be located and provide data compared to authors of older studies. The effects of requests for additional data on the conclusions regarding the utility of blood tests to identify patients with clinically significant fibrosis or cirrhosis were generally small for ten out of 12 tests. Additional data resulted in reclassification (using median likelihood ratio estimates) from less useful to moderately useful or vice versa for the remaining two blood tests and enabled the calculation of an estimate for a third blood test for which previously the data had been insufficient to do so. We did not identify a clear pattern for the directional impact of additional data on estimates of diagnostic accuracy. Conclusions We successfully contacted and received results from 42% of authors who provided data for 38% of included studies. Contacting authors of studies evaluating the diagnostic accuracy of serum biomarkers for hepatic fibrosis and cirrhosis in hepatitis C patients

  20. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    PubMed Central

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  1. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    NASA Astrophysics Data System (ADS)

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-03-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application.

  2. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives.

    PubMed

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  3. Voxel-based lesion-symptom mapping of stroke lesions underlying somatosensory deficits

    PubMed Central

    Meyer, Sarah; Kessner, Simon S.; Cheng, Bastian; Bönstrup, Marlene; Schulz, Robert; Hummel, Friedhelm C.; De Bruyn, Nele; Peeters, Andre; Van Pesch, Vincent; Duprez, Thierry; Sunaert, Stefan; Schrooten, Maarten; Feys, Hilde; Gerloff, Christian; Thomalla, Götz; Thijs, Vincent; Verheyden, Geert

    2015-01-01

    The aim of this study was to investigate the relationship between stroke lesion location and the resulting somatosensory deficit. We studied exteroceptive and proprioceptive somatosensory symptoms and stroke lesions in 38 patients with first-ever acute stroke. The Erasmus modified Nottingham Sensory Assessment was used to clinically evaluate somatosensory functioning in the arm and hand within the first week after stroke onset. Additionally, more objective measures such as the perceptual threshold of touch and somatosensory evoked potentials were recorded. Non-parametric voxel-based lesion-symptom mapping was performed to investigate lesion contribution to different somatosensory deficits in the upper limb. Additionally, structural connectivity of brain areas that demonstrated the strongest association with somatosensory symptoms was determined, using probabilistic fiber tracking based on diffusion tensor imaging data from a healthy age-matched sample. Voxels with a significant association to somatosensory deficits were clustered in two core brain regions: the central parietal white matter, also referred to as the sensory component of the superior thalamic radiation, and the parietal operculum close to the insular cortex, representing the secondary somatosensory cortex. Our objective recordings confirmed findings from clinical assessments. Probabilistic tracking connected the first region to thalamus, internal capsule, brain stem, postcentral gyrus, cerebellum, and frontal pathways, while the second region demonstrated structural connections to thalamus, insular and primary somatosensory cortex. This study reveals that stroke lesions in the sensory fibers of the superior thalamocortical radiation and the parietal operculum are significantly associated with multiple exteroceptive and proprioceptive deficits in the arm and hand. PMID:26900565

  4. [The repeat reliability of somatosensory evoked potentials].

    PubMed

    Strenge, H

    1989-09-01

    The test-immediate-retest reliability of latency and amplitude values of cervical and cortical somatosensory evoked potentials (SEP) to median nerve stimulation was assessed in 86 normal subjects aged 15 to 71 years. In addition to the stability of data between repeat trials within one test session the standard errors of measurement and the interpretable differences for SEP measures were calculated according to measurement theory. The study revealed retest correlations rtt greater than 0.80 for all latency measures of the cervical and cortical SEPs and all cortical amplitude parameters. The highest stability was found for the latency measures of the cervical components P10, N11, N13, the cortical components P16 and N20 and for the amplitude N20/P25. PMID:2507277

  5. Somatosensory loss increases vestibulospinal sensitivity.

    PubMed

    Horak, F B; Hlavacka, F

    2001-08-01

    To determine whether subjects with somatosensory loss show a compensatory increase in sensitivity to vestibular stimulation, we compared the amplitude of postural lean in response to four different intensities of bipolar galvanic stimulation in subjects with diabetic peripheral neuropathy (PNP) and age-matched control subjects. To determine whether healthy and neuropathic subjects show similar increases in sensitivity to galvanic vestibular stimulation when standing on unstable surfaces, both groups were exposed to galvanic stimulation while standing on a compliant foam surface. In these experiments, a 3-s pulse of galvanic current was administered to subjects standing with eyes closed and their heads turned toward one shoulder (anodal current on the forward mastoid). Anterior body tilt, as measured by center of foot pressure (CoP), increased proportionately with increasing galvanic vestibular stimulation intensity for all subjects. Subjects with peripheral neuropathy showed larger forward CoP displacement in response to galvanic stimulation than control subjects. The largest differences between neuropathy and control subjects were at the highest galvanic intensities, indicating an increased sensitivity to vestibular stimulation. Neuropathy subjects showed a larger increase in sensitivity to vestibular stimulation when standing on compliant foam than control subjects. The effect of galvanic stimulation was larger on the movement of the trunk segment in space than on the body's center of mass (CoM) angle, suggesting that the vestibular system acts to control trunk orientation rather than to control whole body posture. This study provides evidence for an increase in the sensitivity of the postural control system to vestibular stimulation when somatosensory information from the surface is disrupted either by peripheral neuropathy or by standing on an unstable surface. Simulations from a simple model of postural orientation incorporating feedback from the vestibular

  6. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  7. Observing motor learning produces somatosensory change.

    PubMed

    Bernardi, Nicolò F; Darainy, Mohammad; Bricolo, Emanuela; Ostry, David J

    2013-10-01

    Observing the actions of others has been shown to affect motor learning, but does it have effects on sensory systems as well? It has been recently shown that motor learning that involves actual physical practice is also associated with plasticity in the somatosensory system. Here, we assessed the idea that observational learning likewise changes somatosensory function. We evaluated changes in somatosensory function after human subjects watched videos depicting motor learning. Subjects first observed video recordings of reaching movements either in a clockwise or counterclockwise force field. They were then trained in an actual force-field task that involved a counterclockwise load. Measures of somatosensory function were obtained before and after visual observation and also following force-field learning. Consistent with previous reports, video observation promoted motor learning. We also found that somatosensory function was altered following observational learning, both in direction and in magnitude, in a manner similar to that which occurs when motor learning is achieved through actual physical practice. Observation of the same sequence of movements in a randomized order did not result in somatosensory perceptual change. Observational learning and real physical practice appear to tap into the same capacity for sensory change in that subjects that showed a greater change following observational learning showed a reliably smaller change following physical motor learning. We conclude that effects of observing motor learning extend beyond the boundaries of traditional motor circuits, to include somatosensory representations.

  8. Human task-specific somatosensory activation.

    PubMed

    Ginsberg, M D; Yoshii, F; Vibulsresth, S; Chang, J Y; Duara, R; Barker, W W; Boothe, T E

    1987-08-01

    We used positron emission tomography to study normal patterns of local cortical metabolic activation induced by somatosensory stimuli. Palpation and sorting of mah-jongg tiles by textured design increased local glucose metabolic rate (lCMRgl), by 18% on average, in contralateral somatosensory cortex. A graphesthesia task gave a similar result. In contrast, vigorous vibrotactile stimulation of fingers, face, or knee did not produce a consistent focus of activation. Our results indicate that lCMRgl activation is best achieved by somatosensory tasks requiring an active perceptual effort.

  9. Imidazolium ionic liquids as antiwear and antioxidant additive in poly(ethylene glycol) for steel/steel contacts.

    PubMed

    Cai, Meirong; Liang, Yongmin; Yao, Meihuan; Xia, Yanqiu; Zhou, Feng; Liu, Weimin

    2010-03-01

    Three imidazolium-based ionic liquids containing sterically hindered phenol groups were synthesized. The cation was 1-(3,5-ditert-butyl-4-hydroxybenzyl)-3-methyl-imidazolium, and the anions were tetrafluoroborates, hexafluorophosphates, and bis(trifluoromethylsulfonyl)imide. The physical properties of the synthetic products and of poly(ethylene glycol) (PEG) with the additive were evaluated. The oxidative stability of 0.5 wt % 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-methyl-imidazolium hexafluorophosphates in PEG were assessed via rotating bomb oxidation test (RBOT), thermal analysis, and copper strip test. The tribological behaviors of the additives for PEG application in steel/steel contacts were evaluated on an Optimol SRV-IV oscillating reciprocating friction and wear tester as well as on MRS-1J four-ball testers. The worn steel surface was analyzed by a JSM-5600LV scanning electron microscope and a PHI-5702 multifunctional X-ray photoelectron spectrometer. RBOT test, thermal analysis, and copper strip test results revealed that synthesized ionic liquids possessed excellent antioxidant properties. Tribological application results revealed that these could effectively reduce friction and wear of sliding pairs compared with the PEG films used without the additives. Specifically, (BHT-1)MIMPF(6) exhibited better antiwear properties at an optimum concentration of 1 wt %. At this level, its antiwear property significantly improved by 100 times with respect to using just the PEG base oil. Boundary lubrication films composed of metal fluorides, organic fluorines, organic phosphines, and nitride compounds were formed on the worn surface, which resulted in excellent friction reduction and antiwear performance. PMID:20356293

  10. Illusory and veridical mapping of tactile objects in the primary somatosensory and posterior parietal cortex.

    PubMed

    Bufalari, Ilaria; Di Russo, Francesco; Aglioti, Salvatore Maria

    2014-07-01

    While several behavioral and neuroscience studies have explored visual, auditory, and cross-modal illusions, information about the phenomenology and neural correlates of somatosensory illusions is meager. By combining psychophysics and somatosensory evoked potentials, we explored in healthy humans the neural correlates of 2 compelling tactuo-proprioceptive illusions, namely Aristotle (1 object touching the contact area between 2 crossed fingers is perceived as 2 lateral objects) and Reverse illusions (2 lateral objects are perceived as 1 between crossed-fingers object). These illusions likely occur because of the tactuo-proprioceptive conflict induced by fingers being crossed in a non-natural posture. We found that different regions in the somatosensory stream exhibit different proneness to the illusions. Early electroencephalographic somatosensory activity (at 20 ms) originating in the primary somatosensory cortex (S1) reflects the phenomenal rather than the physical properties of the stimuli. Notably, later activity (around 200 ms) originating in the posterior parietal cortex is higher when subjects resist the illusions. Thus, while S1 activity is related to illusory perception, PPC acts as a conflict resolver that recodes tactile events from somatotopic to spatiotopic frames of reference and ultimately enables veridical perception. PMID:23438449

  11. Illusory and veridical mapping of tactile objects in the primary somatosensory and posterior parietal cortex.

    PubMed

    Bufalari, Ilaria; Di Russo, Francesco; Aglioti, Salvatore Maria

    2014-07-01

    While several behavioral and neuroscience studies have explored visual, auditory, and cross-modal illusions, information about the phenomenology and neural correlates of somatosensory illusions is meager. By combining psychophysics and somatosensory evoked potentials, we explored in healthy humans the neural correlates of 2 compelling tactuo-proprioceptive illusions, namely Aristotle (1 object touching the contact area between 2 crossed fingers is perceived as 2 lateral objects) and Reverse illusions (2 lateral objects are perceived as 1 between crossed-fingers object). These illusions likely occur because of the tactuo-proprioceptive conflict induced by fingers being crossed in a non-natural posture. We found that different regions in the somatosensory stream exhibit different proneness to the illusions. Early electroencephalographic somatosensory activity (at 20 ms) originating in the primary somatosensory cortex (S1) reflects the phenomenal rather than the physical properties of the stimuli. Notably, later activity (around 200 ms) originating in the posterior parietal cortex is higher when subjects resist the illusions. Thus, while S1 activity is related to illusory perception, PPC acts as a conflict resolver that recodes tactile events from somatotopic to spatiotopic frames of reference and ultimately enables veridical perception.

  12. Effect of low-addition soft contact lenses with decentered optical design on myopia progression in children: a pilot study

    PubMed Central

    Fujikado, Takashi; Ninomiya, Sayuri; Kobayashi, Takuma; Suzaki, Asaki; Nakada, Mitsuhiko; Nishida, Kohji

    2014-01-01

    Purpose To investigate the effect of low-addition soft contact lenses (CLs) with decentered optical design on the progression of myopia in children in a pilot study. Subjects and methods Twenty-four Japanese children age 10–16 years with baseline myopia of −0.75 to −3.50 D sphere and ≤1.00 D cylinder were studied. The new CLs were designed to have a nasal decentration with the optical center centered on the line of sight, and with progressive-addition power of +0.5 D peripherally. Monofocal soft CLs were used as controls. A pair of new CLs or control CLs was randomly assigned to the children, and they wore the lenses for 12 months during the first phase. Then, the type of CLs was changed, ie, a crossover design, and the children were observed for another 12 months during the second phase. The end points were changes in axial length and refractive error (spherical equivalent) under cycloplegia. Results The change of axial length in the new-CL and control-CL groups was not different between 12 months and baseline, the change of axial length between 12 months and 1 month in the new-CL group (0.09±0.08 mm) was significantly smaller (47%) than that in the control-CL group (0.17±0.08 mm, P<0.05). During the same period, the change of refractive error in the new-CL group was not significantly different from that in the control group. Neither the change in axial length nor refractive error in the new-CL group was significantly different from those in the control-CL group in the second phase. Conclusion This pilot study suggests that low-addition soft CLs with decentered optical design can reduce the degree of axial elongation in myopic children after an initial transient phase of CL wear. The reduction of the progression of myopia by low-addition soft CLs warrants further investigations. PMID:25284981

  13. Evolution of somatosensory and motor cortex in primates.

    PubMed

    Kaas, Jon H

    2004-11-01

    Inferences about how the complex somatosensory systems of anthropoid primates evolved are based on comparative studies of such systems in extant mammals. Experimental studies of members of the major clades of extant mammals suggest that somatosensory cortex of early mammals consisted of only a few areas, including a primary area, S1, bordered by strip-like rostral and caudal somatosensory fields, SR and SC. In addition, the second somatosensory area, S2, and the parietal ventral area, PV, were probably present. S1, S2, and PV were activated independently via parallel projections from the ventroposterior nucleus, VP. Little posterior parietal cortex existed, and it was unlikely that a separate primary motor area, M1, existed until placental mammals evolved. Early primates retained this basic organization and also had a larger posterior parietal region that mediated sensorimotor functions via connections with motor and premotor areas. The frontal cortex included M1, dorsal and ventral premotor areas, supplementary motor area, and cingulate motor fields. Ventroposterior superior and ventroposterior inferior nuclei were distinct from the ventroposterior nucleus in the thalamus. In early anthropoid primates, areas S1, SR, and SC had differentiated into the fields now recognized as areas 3b, 3a, and 1. Areas 3b and 1 contained parallel mirror-image representations of cutaneous receptors and a parallel representation in area 2 was probable. Serial processing became dominant, so that neurons in areas 1, S2, and PV became dependent on area 3b for activation. Posterior parietal cortex expanded into more areas that related to frontal cortex. Less is known about changes that might have occurred with the emergence of apes and humans, but their brains were larger and posed scaling problems most likely solved by increasing the number of cortical areas and reducing the proportion of long connections.

  14. Beta 2-adrenergic receptors are colocalized and coregulated with "whisker barrels" in rat somatosensory cortex.

    PubMed Central

    Vos, P; Kaufmann, D; Hand, P J; Wolfe, B B

    1990-01-01

    Autoradiography has been used to visualize independently the subtypes of beta-adrenergic receptors in rat somatosensory cortex. Beta 2-Adrenergic receptors, but not beta 1-adrenergic receptors colocalize with "whisker barrels" in this tissue. Thus, each whisker sends a specific multisynaptic pathway to the somatosensory cortex that can be histochemically visualized and only one subtype of beta-adrenergic receptor is specifically associated with this cortical representation. Additionally, neonatal lesion of any or all of the whisker follicles results in loss of the corresponding barrel(s) as shown by histochemical markers. This loss is paralleled by a similar loss in the organization of beta 2-adrenergic receptors in the somatosensory cortex. Other results indicate that these beta 2-adrenergic receptors are not involved in moment-to-moment signal transmission in this pathway and, additionally, are not involved in a gross way in the development of whisker-barrel array. Images PMID:2164222

  15. The structure of somatosensory information for human postural control

    NASA Technical Reports Server (NTRS)

    Jeka, J. J.; Ribeiro, P.; Oie, K.; Lackner, J. R.

    1998-01-01

    The goal of the present study was to determine the properties of the somatosensory stimulus that alter its temporal coupling to body sway. Six standing subjects were tested while touching a metal plate positioned either directly in front of or lateral to the subject. In each condition, the plate moved 4 mm at 0.2 Hz in either the medial-lateral (ML) or anterior-posterior direction (AP). The results showed that coupling between body sway and touch plate movement was strongest when the touch plate moved in a direction along the longitudinal axis of the arm. Coupling strength was weaker when the touch plate moved perpendicular to the longitudinal axis of the arm. The results consistently show that a radial expansion stimulus was more effective than a lamellar-type stimulus at the fingertip. Moreover, somatosensory information from a surface is interpreted in terms of the orientation of the contact limb and the potential degrees of freedom available through its movement.

  16. Corticocortical connections of cat primary somatosensory cortex.

    PubMed

    Schwark, H D; Esteky, H; Jones, E G

    1992-01-01

    The organization of corticocortical connections in the representation of the forepaw in cat primary somatosensory cortex (SI) was studied following injections of various tracers into different cortical cytoarchitectonic areas. Small injections of horseradish peroxidase, wheat germ agglutinin-conjugated HRP, Phaseolus vulgaris leukoagglutinin, or fast blue were placed into the representation of the forepaw in areas 3b, 1, or 2. The positions of labeled neurons in SI and the surrounding cortical areas were plotted on flattened surface reconstructions to determine the organization of the corticocortical connections within SI. A strong, reciprocal projection linked the two forepaw representations which have been described in area 3b and the part of area 2 which lies in the anterior bank of the lateral ansate sulcus (see Iwamura and Tanaka 1978a, b). Dense projections also linked these areas with SII, as previously reported (Burton and Kopf 1984a). Additional projections to area 3b arose primarily from areas 3a and 1. Projections to area 2 were more widespread than those to area 3b, and arose from all other areas of SI as well as from areas 4 and 5a. All injections into SI tended to label groups of neurons which lay in mediolateral strips. Corticocortical projection neurons which were most heavily labeled by SI injections were pyramidal cells in layer III. Additional projections from area 2 to 3b, area 5a to 2, and SII to areas 2 and 3b arose from layer VI as well. Although neurons of layers III and VI were always the most densely labeled, large injections into SI labeled neurons in layers II and V as well. PMID:1282890

  17. Effective behavioral treatment of focal hand dystonia in musicians alters somatosensory cortical organization.

    PubMed

    Candia, Victor; Wienbruch, Christian; Elbert, Thomas; Rockstroh, Brigitte; Ray, William

    2003-06-24

    New perspectives in neurorehabilitation suggest that behavioral treatments of movement disorders may modify the functional organization of central somatosensory neural networks. On the basis of the assumption that use-dependent reorganization in these networks contributes to the fundamental abnormalities seen in focal dystonia, we treated 10 affected musicians and measured the concomitant somatosensory changes by using whole-head magnetoencephalography. We found that effective treatment, using the method of sensory motor retuning, leads to alterations in the functional organization of the somatosensory cortex. Specifically, before treatment, somatosensory relationships of the individual fingers differ between the affected and unaffected hands, whereas after treatment, finger representations contralateral to the dystonic side become more similar to the less-affected side. Further, somatosensory finger representations are ordered more according to homuncular principles after treatment. In addition, the observed physiologic changes correlated with behavioral data. These results confirm that plastic changes in parallel with emergent neurological dysfunction may be reversed by context-specific, intensive training-based remediation.

  18. Effective behavioral treatment of focal hand dystonia in musicians alters somatosensory cortical organization

    PubMed Central

    Candia, Victor; Wienbruch, Christian; Elbert, Thomas; Rockstroh, Brigitte; Ray, William

    2003-01-01

    New perspectives in neurorehabilitation suggest that behavioral treatments of movement disorders may modify the functional organization of central somatosensory neural networks. On the basis of the assumption that use-dependent reorganization in these networks contributes to the fundamental abnormalities seen in focal dystonia, we treated 10 affected musicians and measured the concomitant somatosensory changes by using whole-head magnetoencephalography. We found that effective treatment, using the method of sensory motor retuning, leads to alterations in the functional organization of the somatosensory cortex. Specifically, before treatment, somatosensory relationships of the individual fingers differ between the affected and unaffected hands, whereas after treatment, finger representations contralateral to the dystonic side become more similar to the less-affected side. Further, somatosensory finger representations are ordered more according to homuncular principles after treatment. In addition, the observed physiologic changes correlated with behavioral data. These results confirm that plastic changes in parallel with emergent neurological dysfunction may be reversed by context-specific, intensive training-based remediation. PMID:12771383

  19. COMMUNICATION Designing a somatosensory neural prosthesis: percepts evoked by different patterns of thalamic stimulation

    NASA Astrophysics Data System (ADS)

    Heming, Ethan; Sanden, Andrew; Kiss, Zelma H. T.

    2010-12-01

    Although major advances have been made in the development of motor prostheses, fine motor control requires intuitive somatosensory feedback. Here we explored whether a thalamic site for a somatosensory neural prosthetic could provide natural somatic sensation to humans. Different patterns of electrical stimulation (obtained from thalamic spike trains) were applied in patients undergoing deep brain stimulation surgery. Changes in pattern produced different sensations, while preserving somatotopic representation. While most percepts were reported as 'unnatural', some stimulations produced more 'natural' sensations than others. However, the additional patterns did not elicit more 'natural' percepts than high-frequency (333 Hz) electrical stimulation. These features suggest that despite some limitations, the thalamus may be a feasible site for a somatosensory neural prosthesis and different stimulation patterns may be useful in its development.

  20. Somatosensory Neurotoxicity: Agents and Assessment Methodology

    EPA Science Inventory

    The somatosensory system is comprised of a variety of sensory receptors located in the skin, muscle tendons, and visceral organs that are innervated by myelinated and nonmyelinated axons of the peripheral nervous system. These peripheral sensory nerve fibers in turn communicate s...

  1. Enhanced computational prediction of polyethylene wear in hip joints by incorporating cross-shear and contact pressure in additional to load and sliding distance: effect of head diameter.

    PubMed

    Kang, Lu; Galvin, Alison L; Fisher, John; Jin, Zhongmin

    2009-05-11

    A new definition of the experimental wear factor was established and reported as a function of cross-shear motion and contact pressure using a multi-directional pin-on-plate wear testing machine for conventional polyethylene in the present study. An independent computational wear model was developed by incorporating the cross-shear motion and contact pressure-dependent wear factor into the Archard's law, in additional to load and sliding distance. The computational prediction of wear volume was directly compared with a simulator testing of a polyethylene hip joint with a 28 mm diameter. The effect of increasing the femoral head size was subsequently considered and was shown to increase wear, as a result of increased sliding distance and reduced contact pressure. PMID:19261286

  2. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  3. Decoding Visual Object Categories in Early Somatosensory Cortex

    PubMed Central

    Smith, Fraser W.; Goodale, Melvyn A.

    2015-01-01

    Neurons, even in the earliest sensory areas of cortex, are subject to a great deal of contextual influence from both within and across modality connections. In the present work, we investigated whether the earliest regions of somatosensory cortex (S1 and S2) would contain content-specific information about visual object categories. We reasoned that this might be possible due to the associations formed through experience that link different sensory aspects of a given object. Participants were presented with visual images of different object categories in 2 fMRI experiments. Multivariate pattern analysis revealed reliable decoding of familiar visual object category in bilateral S1 (i.e., postcentral gyri) and right S2. We further show that this decoding is observed for familiar but not unfamiliar visual objects in S1. In addition, whole-brain searchlight decoding analyses revealed several areas in the parietal lobe that could mediate the observed context effects between vision and somatosensation. These results demonstrate that even the first cortical stages of somatosensory processing carry information about the category of visually presented familiar objects. PMID:24122136

  4. Look but don't touch: Visual cues to surface structure drive somatosensory cortex

    PubMed Central

    Sun, Hua-Chun; Welchman, Andrew E.; Chang, Dorita H.F.; Di Luca, Massimiliano

    2016-01-01

    When planning interactions with nearby objects, our brain uses visual information to estimate shape, material composition, and surface structure before we come into contact with them. Here we analyse brain activations elicited by different types of visual appearance, measuring fMRI responses to objects that are glossy, matte, rough, or textured. In addition to activation in visual areas, we found that fMRI responses are evoked in the secondary somatosensory area (S2) when looking at glossy and rough surfaces. This activity could be reliably discriminated on the basis of tactile-related visual properties (gloss, rough, and matte), but importantly, other visual properties (i.e., coloured texture) did not substantially change fMRI activity. The activity could not be solely due to tactile imagination, as asking explicitly to imagine such surface properties did not lead to the same results. These findings suggest that visual cues to an object's surface properties evoke activity in neural circuits associated with tactile stimulation. This activation may reflect the a-priori probability of the physics of the interaction (i.e., the expectation of upcoming friction) that can be used to plan finger placement and grasp force. PMID:26778128

  5. [The cerebral control of afferent somatosensory projections].

    PubMed

    Petrenko, E V; Orlova, T V; Liubimov, N N

    1993-09-01

    Cortical and dorsal column nuclei somatosensory evoked potentials (SEP) induced by electrical stimulation of the median nerve were recorded and analysed in 16 healthy volunteers practising transcendental meditation (TM) for two years. The records were performed before and during TM. The SEP changes during TM consisted of an increase in early SEP components amplitude. There were no changes in early SEP components peak latencies during TM.

  6. Mnemonic neuronal activity in somatosensory cortex.

    PubMed Central

    Zhou, Y D; Fuster, J M

    1996-01-01

    Single-unit activity was recorded from the hand areas of the somatosensory cortex of monkeys trained to perform a haptic delayed matching to sample task with objects of identical dimensions but different surface features. During the memory retention period of the task (delay), many units showed sustained firing frequency change, either excitation or inhibition. In some cases, firing during that period was significantly higher after one sample object than after another. These observations indicate the participation of somatosensory neurons not only in the perception but in the short-term memory of tactile stimuli. Neurons most directly implicated in tactile memory are (i) those with object-selective delay activity, (ii) those with nondifferential delay activity but without activity related to preparation for movement, and (iii) those with delay activity in the haptic-haptic delayed matching task but no such activity in a control visuo-haptic delayed matching task. The results indicate that cells in early stages of cortical somatosensory processing participate in haptic short-term memory. PMID:8927629

  7. Effects of changing illuminance on somatosensory function.

    PubMed

    Yoshinaga, Naoki; Fujita, Mizuho; Tanaka, Yuji L; Nemoto, Seiji

    2011-01-01

    Artificial sources of illumination can be easily used, regardless of the time and place, to improve visibility at night and in dark places. Illuminance and color temperature are particularly important factors since they are known to elicit physiological effects. However, the relationship between changes in illuminance and somatosensory function has not been sufficiently clarified. Thus, the purpose of this study was to construct a laboratorial model to examine the effects of lowering or raising illuminance on somatosensory function. Three illuminance levels (200 lx, 50 lx, and 0 lx), which were changed using all combinations, and an artificial sensory stimulus maintained at a constant intensity were presented to the subjects of this study. Objective sensory function in response to the sensory stimulus was investigated by somatosensory evoked potential (SEP), and subjective sensory evaluation in response to the stimulus was investigated using a visual analogue scale (VAS) and by interview. In many cases, the SEP amplitude and VAS value tended to decrease when illuminance was lowered and tended to increase when illuminance was raised. However, in a few cases, SEP amplitude and VAS value tended to increase in spite of the low illuminance. The occurrence of attention responses and unpleasant emotional responses caused by lowering the illuminance seems to be related to this study finding.

  8. Somatosensory Pulsatile Tinnitus Syndrome: Somatic Testing Identifies a Pulsatile Tinnitus Subtype That Implicates the Somatosensory System

    PubMed Central

    Levine, Robert Aaron; Nam, Eui-Cheol; Melcher, Jennifer

    2008-01-01

    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. PMID:18632767

  9. Individual differences in cortical connections of somatosensory cortex are associated with parental rearing style in prairie voles (Microtus ochrogaster).

    PubMed

    Seelke, Adele M H; Perkeybile, Allison M; Grunewald, Rebecca; Bales, Karen L; Krubitzer, Leah A

    2016-02-15

    Early-life sensory experiences have a profound effect on brain organization, connectivity, and subsequent behavior. In most mammals, the earliest sensory inputs are delivered to the developing brain through tactile contact with the parents, especially the mother. Prairie voles (Microtus ochrogaster) are monogamous and, like humans, are biparental. Within the normal prairie vole population, both the type and the amount of interactions, particularly tactile contact, that parents have with their offspring vary. The question is whether these early and pervasive differences in tactile stimulation and social experience between parent and offspring are manifest in differences in cortical organization and connectivity. To address this question, we examined the cortical and callosal connections of the primary somatosensory area (S1) in high-contact (HC) and low-contact (LC) offspring using neuroanatomical tracing techniques. Injection sites within S1 were matched so that direct comparisons between these two groups could be made. We observed several important differences between these groups. The first was that HC offspring had a greater density of intrinsic connections within S1 compared with LC offspring. Additionally, HC offspring had a more restricted pattern of ipsilateral connections, whereas LC offspring had dense connections with areas of parietal and frontal cortex that were more widespread. Finally, LC offspring had a broader distribution of callosal connections than HC offspring and a significantly higher percentage of labeled callosal neurons. This study is the first to examine individual differences in cortical connections and suggests that individual differences in cortical connections may be related to natural differences in parental rearing styles associated with tactile contact.

  10. Individual differences in cortical connections of somatosensory cortex are associated with parental rearing style in prairie voles (Microtus ochrogaster).

    PubMed

    Seelke, Adele M H; Perkeybile, Allison M; Grunewald, Rebecca; Bales, Karen L; Krubitzer, Leah A

    2016-02-15

    Early-life sensory experiences have a profound effect on brain organization, connectivity, and subsequent behavior. In most mammals, the earliest sensory inputs are delivered to the developing brain through tactile contact with the parents, especially the mother. Prairie voles (Microtus ochrogaster) are monogamous and, like humans, are biparental. Within the normal prairie vole population, both the type and the amount of interactions, particularly tactile contact, that parents have with their offspring vary. The question is whether these early and pervasive differences in tactile stimulation and social experience between parent and offspring are manifest in differences in cortical organization and connectivity. To address this question, we examined the cortical and callosal connections of the primary somatosensory area (S1) in high-contact (HC) and low-contact (LC) offspring using neuroanatomical tracing techniques. Injection sites within S1 were matched so that direct comparisons between these two groups could be made. We observed several important differences between these groups. The first was that HC offspring had a greater density of intrinsic connections within S1 compared with LC offspring. Additionally, HC offspring had a more restricted pattern of ipsilateral connections, whereas LC offspring had dense connections with areas of parietal and frontal cortex that were more widespread. Finally, LC offspring had a broader distribution of callosal connections than HC offspring and a significantly higher percentage of labeled callosal neurons. This study is the first to examine individual differences in cortical connections and suggests that individual differences in cortical connections may be related to natural differences in parental rearing styles associated with tactile contact. PMID:26101098

  11. Aberrant synchrony in the somatosensory cortices predicts motor performance errors in children with cerebral palsy.

    PubMed

    Kurz, Max J; Heinrichs-Graham, Elizabeth; Arpin, David J; Becker, Katherine M; Wilson, Tony W

    2014-02-01

    Cerebral palsy (CP) results from a perinatal brain injury that often results in sensory impairments and greater errors in motor performance. Although these impairments have been well catalogued, the relationship between sensory processing networks and errors in motor performance has not been well explored. Children with CP and typically developing age-matched controls participated in this investigation. We used high-density magnetoencephalography to measure event-related oscillatory changes in the somatosensory cortices following tactile stimulation to the bottom of the foot. In addition, we quantified the amount of variability or errors in the isometric ankle joint torques as these children attempted to match a target. Our results showed that neural populations in the somatosensory cortices of children with CP were desynchronized by the tactile stimulus, whereas those of typically developing children were clearly synchronized. Such desynchronization suggests that children with CP were unable to fully integrate the external stimulus into ongoing sensorimotor computations. Our results also indicated that children with CP had a greater amount of errors in their motor output when they attempted to match the target force, and this amount of error was negatively correlated with the degree of synchronization present in the somatosensory cortices. These results are the first to show that the motor performance errors of children with CP are linked with neural synchronization within the somatosensory cortices.

  12. Perceiving Invisible Light through a Somatosensory Cortical Prosthesis

    PubMed Central

    Thomson, Eric E.; Carra, Rafael; Nicolelis, Miguel A.L.

    2013-01-01

    Sensory neuroprostheses show great potential for alleviating major sensory deficits. It is not known, however, whether such devices can augment the subject’s normal perceptual range. Here we show that adult rats can learn to perceive otherwise invisible infrared (IR) light through a neuroprosthesis that couples the output of a head-mounted IR sensor to their somatosensory cortex (S1) via intracortical microstimulation (ICMS). Rats readily learn to use this new information source, and generate active exploratory strategies to discriminate among IR sources in their environment. S1 neurons in these IR-perceiving rats respond to both whisker deflection and ICMS, suggesting that the IR representation does not displace the original tactile representation. Hence, sensory cortical prostheses, in addition to restoring normal neurological functions, may serve to expand natural perceptual capabilities in mammals. PMID:23403583

  13. Differences in somatosensory hand organization in a healthy flutist and a flutist with focal hand dystonia: a case report.

    PubMed

    Byl, N N; McKenzie, A; Nagarajan, S S

    2000-01-01

    Focal hand dystonia is a disabling, involuntary disorder of movement that can disrupt a successful musician's career. This problem is difficult to treat, to some extent because we do not fully understand its origin. Somatosensory degradation has been proposed as one etiology. The purpose of this case study was to compare the differences in the somatosensory hand representation of two female flutists, one with focal dystonia of the left hand (digits 4 and 5) and one a healthy subject (the control). Noninvasive magnetic source imaging was performed on both subjects. The somatosensory evoked potentials of controlled taps to the fingers were measured with a 37-channel biomagnetometer and reported in terms of the neuronal organization, latency, amplitude, density, location, and spread of the digits on each axis (x, y, and z). The somatosensory representation of the involved hand of the flutist with dystonia differed from that of the healthy flutist. The magnetic fields evoked from the primary somatosensory cortex had a disorganized pattern of firing, with a short latency and excessive amplitude in the involved digits of the affected hand, as well as inconsistency (decreased density). In addition, the patterns of firing were different in terms of the location of the digits on the x, y, and z axes and sequential organization of the digits. This study confirms that somatosensory evoked magnetic fields can be used to describe the representation of the hand on the somatosensory cortex in area 3b. Degradation in the hand representation of the flutist with focal hand dystonia was evident, compared with the hand representation of the healthy flutist. It is not clear whether the sensory degradation was the cause or the consequence of the dystonia. The questions are whether re-differentiation of the representation could be achieved with aggressive sensory retraining and whether improvement in structure would be correlated with improvement in function.

  14. Identification and characterization of somatosensory off responses.

    PubMed

    Spackman, Lynne; Boyd, Stewart; Towell, Tony

    2006-10-01

    Event-related potentials (ERPs) have been recorded in response to the offset of sensory stimulation in both the auditory and visual modalities. The present experiment employed vibratory stimulation to characterize somatosensory ERPs in response to different duration stimuli. In two separate experiments, we recorded attended and unattended somatosensory ERPs to 70 Hz, sine wave stimuli using the following durations: 20 ms, 50 ms, 70 ms, 150 ms, 170 ms, 250 ms and 1000 ms. An oscillating coil delivered stimuli through a 'T-bar' to digits 2 and 3 of the right hand. The amplitude and latency measurements of P50, P100 and a later negative component (No1) were analyzed using MANOVA. There was no significant difference in the latency values of the P50 and P100, but as the duration increased, there was a significant increase (P < 0.01) in the latency of No1. No1 appeared 130 ms +/- 9 ms following the offset of the stimulus. Amplitude values of the P50 and P100 components decreased as the stimulus duration increased and this effect became significant (P < 0.05) as the duration difference increased. Stimuli of 150 ms or greater evoked a negative baseline shift that persisted for the duration of the stimulus and area measurements in 7 out of the 10 subjects showed a significant increase in amplitude when the stimulus was attended. An intracranial case study supported these findings. The characteristics of the No1 component indicate it is a somatosensory off response, and it, in conjunction with the P50 and sustained potential, may reflect activity of a neural system that is responsive to changes in the tactile environment. PMID:16952337

  15. [Age changes in early somatosensory evoked potentials].

    PubMed

    Strenge, H

    1986-06-01

    There are characteristic age-related changes in the cervical and early cortical somatosensory potentials evoked by electrical stimulation of the median nerve. At an age of 40 to 50 years the latencies of the potential components and the transit times start increasing progressively. Moreover, there is an attenuation of the cervical and an enhancement of the cortical components with age. Considering the presumed neuronal basis of the bioelectric phenomena the changes are discussed in connection with aging processes of the spinal ganglion cells, cortical pyramidal cells and the locus coeruleus. PMID:3017682

  16. Differences in somatosensory processing due to dominant hemispheric motor impairment in cerebral palsy

    PubMed Central

    2014-01-01

    Background Although cerebral palsy (CP) is usually defined as a group of permanent motor disorders due to non-progressive disturbances in the developing fetal or infant brain, recent research has shown that CP individuals are also characterized by altered somatosensory perception, increased pain and abnormal activation of cortical somatosensory areas. The present study was aimed to examine hemispheric differences on somatosensory brain processing in individuals with bilateral CP and lateralized motor impairments compared with healthy controls. Nine CP individuals with left-dominant motor impairments (LMI) (age range 5–28 yrs), nine CP individuals with right-dominant motor impairments (RMI) (age range 7–29 yrs), and 12 healthy controls (age range 5–30 yrs) participated in the study. Proprioception, touch and pain thresholds, as well as somatosensory evoked potentials (SEP) elicited by tactile stimulation of right and left lips and thumbs were compared. Results Pain sensitivity was higher, and lip stimulation elicited greater beta power and more symmetrical SEP amplitudes in individuals with CP than in healthy controls. In addition, although there was no significant differences between individuals with RMI and LMI on pain or touch sensitivity, lip and thumb stimulation elicited smaller beta power and more symmetrical SEP amplitudes in individuals with LMI than with RMI. Conclusions Our data revealed that brain processing of somatosensory stimulation was abnormal in CP individuals. Moreover, this processing was different depending if they presented right- or left-dominant motor impairments, suggesting that different mechanisms of sensorimotor reorganization should be involved in CP depending on dominant side of motor impairment. PMID:24410983

  17. Behavioral demonstration of a somatosensory neuroprosthesis.

    PubMed

    Berg, J A; Dammann, J F; Tenore, F V; Tabot, G A; Boback, J L; Manfredi, L R; Peterson, M L; Katyal, K D; Johannes, M S; Makhlin, A; Wilcox, R; Franklin, R K; Vogelstein, R J; Hatsopoulos, N G; Bensmaia, S J

    2013-05-01

    Tactile sensation is critical for effective object manipulation, but current prosthetic upper limbs make no provision for delivering somesthetic feedback to the user. For individuals who require use of prosthetic limbs, this lack of feedback transforms a mundane task into one that requires extreme concentration and effort. Although vibrotactile motors and sensory substitution devices can be used to convey gross sensations, a direct neural interface is required to provide detailed and intuitive sensory feedback. In light of this, we describe the implementation of a somatosensory prosthesis with which we elicit, through intracortical microstimulation (ICMS), percepts whose magnitude is graded according to the force exerted on the prosthetic finger. Specifically, the prosthesis consists of a sensorized finger, the force output of which is converted into a regime of ICMS delivered to primary somatosensory cortex through chronically implanted multi-electrode arrays. We show that the performance of animals (Rhesus macaques) on a tactile task is equivalent whether stimuli are delivered to the native finger or to the prosthetic finger. PMID:23475375

  18. Passive somatosensory discrimination tasks in healthy volunteers: differential networks involved in familiar versus unfamiliar shape and length discrimination.

    PubMed

    Van de Winckel, Ann; Sunaert, Stefan; Wenderoth, Nicole; Peeters, Ron; Van Hecke, Paul; Feys, Hilde; Horemans, Els; Marchal, Guy; Swinnen, Stephan P; Perfetti, Carlo; De Weerdt, Willy

    2005-06-01

    Somatosensory discrimination of unseen objects relies on processing of proprioceptive and tactile information to detect spatial features, such as shape or length, as acquired by exploratory finger movements. This ability can be impaired after stroke, because of somatosensory-motor deficits. Passive somatosensory discrimination tasks are therefore used in therapy to improve motor function. Whereas the neural correlates of active discrimination have been addressed repeatedly, little is known about the neural networks activated during passive discrimination of somatosensory information. In the present study, we applied functional magnetic resonance imaging (fMRI) while the right index finger of ten healthy subjects was passively moved along various shapes and lengths by an fMRI compatible robot. Comparing discriminating versus non-discriminating passive movements, we identified a bilateral parieto-frontal network, including the precuneus, superior parietal gyrus, rostral intraparietal sulcus, and supramarginal gyrus as well as the supplementary motor area (SMA), dorsal premotor (PMd), and ventral premotor (PMv) areas. Additionally, we compared the discrimination of different spatial features, i.e., discrimination of length versus familiar (rectangles or triangles) and unfamiliar geometric shapes (arbitrary quadrilaterals). Length discrimination activated mainly medially located superior parietal and PMd circuits whereas discrimination of familiar geometric shapes activated more laterally located inferior parietal and PMv regions. These differential parieto-frontal circuits provide new insights into the neural basis of extracting spatial features from somatosensory input and suggest that different passive discrimination tasks could be used for lesion-specific training following stroke.

  19. Visual Responses of Neurons in Somatosensory Cortex of Hamsters with Experimentally Induced Retinal Projections to Somatosensory Thalamus

    NASA Astrophysics Data System (ADS)

    Metin, Christine; Frost, Douglas O.

    1989-01-01

    These experiments investigate the capacity of thalamic and cortical structures in a sensory system to process information of a modality normally associated with another system. Retinal ganglion cells in newborn Syrian hamsters were made to project permanently to the main thalamic somatosensory (ventrobasal) nucleus. When the animals were adults, single unit recordings were made in the somatosensory cortices, the principal targets of the ventrobasal nucleus. The somatosensory neurons responded to visual stimulation of distinct receptive fields, and their response properties resembled, in several characteristic features, those of normal visual cortical neurons. In the visual cortex of normal animals and the somatosensory cortex of operated animals, the same functional categories of neurons occurred in similar proportions, and the neurons' selectivity for the orientation or direction of movement of visual stimuli was comparable. These results suggest that thalamic nuclei or cortical areas at corresponding levels in the visual and somatosensory pathways perform similar transformations on their inputs.

  20. Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes.

    PubMed

    Zheng, Libing; Wu, Zhenjun; Zhang, Yong; Wei, Yuansong; Wang, Jun

    2016-07-01

    Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2O were used to prepare poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation (DCMD) of 3.5g/L NaCl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol (PEG), organic acids, LiCl, MgCl2, and LiCl/H2O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate (DBP) showed a nonporous surface and symmetrical cross-section. When H2O and LiCl/H2O mixtures were also used as additives, they were beneficial for solid-liquid demixing, especially when LiCl/H2O mixed additives were used. The membrane prepared with 5% LiCl+2% H2O achieved a flux of 24.53kg/(m(2)·hr) with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes. PMID:27372116

  1. Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes.

    PubMed

    Zheng, Libing; Wu, Zhenjun; Zhang, Yong; Wei, Yuansong; Wang, Jun

    2016-07-01

    Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2O were used to prepare poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation (DCMD) of 3.5g/L NaCl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol (PEG), organic acids, LiCl, MgCl2, and LiCl/H2O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate (DBP) showed a nonporous surface and symmetrical cross-section. When H2O and LiCl/H2O mixtures were also used as additives, they were beneficial for solid-liquid demixing, especially when LiCl/H2O mixed additives were used. The membrane prepared with 5% LiCl+2% H2O achieved a flux of 24.53kg/(m(2)·hr) with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes.

  2. Congruency of body-related information induces somatosensory reorganization.

    PubMed

    Cardini, Flavia; Longo, Matthew R

    2016-04-01

    Chronic pain and impaired tactile sensitivity are frequently associated with "blurred" representations in the somatosensory cortex. The factors that produce such somatosensory blurring, however, remain poorly understood. We manipulated visuo-tactile congruence to investigate its role in promoting somatosensory reorganization. To this aim we used the mirror box illusion that produced in participants the subjective feeling of looking directly at their left hand, though they were seeing the reflection of their right hand. Simultaneous touches were applied to the middle or ring finger of each hand. In one session, the same fingers were touched (for example both middle fingers), producing a congruent percept; in the other session different fingers were touched, producing an incongruent percept. In the somatosensory system, suppressive interactions between adjacent stimuli are an index of intracortical inhibitory function. After each congruent and incongruent session, we recorded somatosensory evoked potential (SEPs) elicited by electrocutaneous stimulation of the left ring and middle fingers, either individually or simultaneously. A somatosensory suppression index (SSI) was calculated as the difference in amplitude between the sum of potentials evoked by the two individually stimulated fingers and the potentials evoked by simultaneous stimulation of both fingers. This SSI can be taken as an index of the strength of inhibitory interactions and consequently can provide a measure of how distinct the representations of the two fingers are. Results showed stronger SSI in the P100 component after congruent than incongruent stimulation, suggesting the key role of congruent sensory information about the body in inducing somatosensory reorganization. PMID:26902158

  3. Clinical application of somatosensory amplification in psychosomatic medicine

    PubMed Central

    Nakao, Mutsuhiro; Barsky, Arthur J

    2007-01-01

    Many patients with somatoform disorders are frequently encountered in psychosomatic clinics as well as in primary care clinics. To assess such patients objectively, the concept of somatosensory amplification may be useful. Somatosensory amplification refers to the tendency to experience a somatic sensation as intense, noxious, and disturbing. It may have a role in a variety of medical conditions characterized by somatic symptoms that are disproportionate to demonstrable organ pathology. It may also explain some of the variability in somatic symptomatology found among different patients with the same serious medical disorder. It has been assessed with a self-report questionnaire, the Somatosensory Amplification Scale. This instrument was developed in a clinical setting in the U.S., and the reliability and validity of the Japanese and Turkish versions have been confirmed as well. Many studies have attempted to clarify the specific role of somatosensory amplification as a pathogenic mechanism in somatization. It has been reported that somatosensory amplification does not correlate with heightened sensitivity to bodily sensations and that emotional reactivity exerts its influence on somatization via a negatively biased reporting style. According to our recent electroencephalographic study, somatosensory amplification appears to reflect some aspects of long-latency cognitive processing rather than short-latency interoceptive sensitivity. The concept of somatosensory amplification can be useful as an indicator of somatization in the therapy of a broad range of disorders, from impaired self-awareness to various psychiatric disorders. It also provides useful information for choosing appropriate pharmacological or psychological therapy. While somatosensory amplification has a role in the presentation of somatic symptoms, it is closely associated with other factors, namely, anxiety, depression, and alexithymia that may also influence the same. The specific role of

  4. Somatosensory Substrates of Flight Control in Bats

    PubMed Central

    Marshall, Kara L.; Chadha, Mohit; deSouza, Laura A.; Sterbing-D’Angelo, Susanne J.; Moss, Cynthia F.; Lumpkin, Ellen A.

    2015-01-01

    Summary Flight maneuvers require rapid sensory integration to generate adaptive motor output. Bats achieve remarkable agility with modified forelimbs that serve as airfoils while retaining capacity for object manipulation. Wing sensory inputs provide behaviorally relevant information to guide flight; however, components of wing sensory-motor circuits have not been analyzed. Here, we elucidate the organization of wing innervation in an insectivore, the big brown bat, Eptesicus fuscus. We demonstrate that wing sensory innervation differs from other vertebrate forelimbs, revealing a peripheral basis for the atypical topographic organization reported for bat somatosensory nuclei. Furthermore, the wing is innervated by an unusual complement of sensory neurons poised to report airflow and touch. Finally, we report that cortical neurons encode tactile and airflow inputs with sparse activity patterns. Together, our findings identify neural substrates of somatosensation in the bat wing and imply that evolutionary pressures giving rise to mammalian flight led to unusual sensorimotor projections. PMID:25937277

  5. Somatosensory substrates of flight control in bats.

    PubMed

    Marshall, Kara L; Chadha, Mohit; deSouza, Laura A; Sterbing-D'Angelo, Susanne J; Moss, Cynthia F; Lumpkin, Ellen A

    2015-05-12

    Flight maneuvers require rapid sensory integration to generate adaptive motor output. Bats achieve remarkable agility with modified forelimbs that serve as airfoils while retaining capacity for object manipulation. Wing sensory inputs provide behaviorally relevant information to guide flight; however, components of wing sensory-motor circuits have not been analyzed. Here, we elucidate the organization of wing innervation in an insectivore, the big brown bat, Eptesicus fuscus. We demonstrate that wing sensory innervation differs from other vertebrate forelimbs, revealing a peripheral basis for the atypical topographic organization reported for bat somatosensory nuclei. Furthermore, the wing is innervated by an unusual complement of sensory neurons poised to report airflow and touch. Finally, we report that cortical neurons encode tactile and airflow inputs with sparse activity patterns. Together, our findings identify neural substrates of somatosensation in the bat wing and imply that evolutionary pressures giving rise to mammalian flight led to unusual sensorimotor projections.

  6. [Somatosensory evoked potentials in moderate hyperthermia].

    PubMed

    Strenge, H

    1991-09-01

    The effects of moderate whole-body hyperthermia on the cervical and cortical somatosensory evoked potentials (SEP) were studied in healthy male subjects, aged 22-32 years. They were immersed in hot water and heated to a median rectal temperature of 39.0 degrees C. Serial SEPs to median nerve stimulation were recorded during cooling at intervals of 0.1 degrees C. The general wave form and the amplitudes did not systematically change. For a 1 degrees C drop there was a median latency increase of 2.6-3.7% in cervical and 1.5-7.4% in cortical SEP components. In individual cases significant latency delays of cervical N13 and cortical N20 could already be observed at differences of 0.2 degrees and 0.5 degrees respectively. All other components showed significant latency changes at temperature intervals of 0.6 to 0.8 degrees C. PMID:1765026

  7. Somatosensory responses in a human motor cortex.

    PubMed

    Shaikhouni, Ammar; Donoghue, John P; Hochberg, Leigh R

    2013-04-01

    Somatic sensory signals provide a major source of feedback to motor cortex. Changes in somatosensory systems after stroke or injury could profoundly influence brain computer interfaces (BCI) being developed to create new output signals from motor cortex activity patterns. We had the unique opportunity to study the responses of hand/arm area neurons in primary motor cortex to passive joint manipulation in a person with a long-standing brain stem stroke but intact sensory pathways. Neurons responded to passive manipulation of the contralateral shoulder, elbow, or wrist as predicted from prior studies of intact primates. Thus fundamental properties and organization were preserved despite arm/hand paralysis and damage to cortical outputs. The same neurons were engaged by attempted arm actions. These results indicate that intact sensory pathways retain the potential to influence primary motor cortex firing rates years after cortical outputs are interrupted and may contribute to online decoding of motor intentions for BCI applications.

  8. Somatosensory responses in a human motor cortex

    PubMed Central

    Donoghue, John P.; Hochberg, Leigh R.

    2013-01-01

    Somatic sensory signals provide a major source of feedback to motor cortex. Changes in somatosensory systems after stroke or injury could profoundly influence brain computer interfaces (BCI) being developed to create new output signals from motor cortex activity patterns. We had the unique opportunity to study the responses of hand/arm area neurons in primary motor cortex to passive joint manipulation in a person with a long-standing brain stem stroke but intact sensory pathways. Neurons responded to passive manipulation of the contralateral shoulder, elbow, or wrist as predicted from prior studies of intact primates. Thus fundamental properties and organization were preserved despite arm/hand paralysis and damage to cortical outputs. The same neurons were engaged by attempted arm actions. These results indicate that intact sensory pathways retain the potential to influence primary motor cortex firing rates years after cortical outputs are interrupted and may contribute to online decoding of motor intentions for BCI applications. PMID:23343902

  9. Oral structure representation in human somatosensory cortex.

    PubMed

    Tamura, Yohei; Shibukawa, Yoshiyuki; Shintani, Masuro; Kaneko, Yuzuru; Ichinohe, Tatsuya

    2008-10-15

    To clarify the topography of the areas representing whole intraoral structures and elucidate bilateral neuronal projection to those areas in the primary somatosensory (S1) cortex, we recorded somatosensory-evoked magnetic fields (SEFs), which reflect the earliest cortical responses to pure tactile stimulation, using magnetoencephalography and a piezo-driven tactile stimulation device. Subjects consisted of 10 healthy male adults. Following tactile stimulation of 6 sites on the oral mucosa (inferior/superior buccal mucosa, posterior/anterior tongue mucosa, and upper/lower lip mucosa), SEFs with a peak latency of 15 ms (1M) were identified bilaterally. In contrast, SEFs with a peak latency of 30 ms following right index finger tactile stimulation were identified only in the contralateral hemisphere. Equivalent current dipoles (ECDs) generating 15 ms components were found along the posterior wall of the central sulcus, bilaterally. The ECD locations for oral mucosa-representing areas were located inferiorly to those for the index finger, with the following pattern of organization from top to bottom along the central sulcus: index finger, upper or lower lip, anterior or posterior tongue and superior or inferior buccal mucosa, with a wide distribution, covering 30% of the S1 cortex. Source strength for 1M in the ipsilateral hemisphere was weaker than that in the contralateral hemisphere. These results clearly indicate that sensory afferents innervating the intraoral region project to both the contralateral and ipsilateral 3b areas via the trigeminothalamic tract, where contralateral projection is predominant. The results clarify the intraoral structure-representing areas in the S1 cortex, adding those areas to the classical "sensory homunculus". PMID:18672075

  10. Modality-Based Organization of Ascending Somatosensory Axons in the Direct Dorsal Column Pathway

    PubMed Central

    Niu, Jingwen; Ding, Long; Li, Jian J.; Kim, Hyukmin; Liu, Jiakun; Li, Haipeng; Moberly, Andrew; Badea, Tudor C.; Duncan, Ian D.; Son, Young-Jin; Scherer, Steven S.

    2013-01-01

    The long-standing doctrine regarding the functional organization of the direct dorsal column (DDC) pathway is the “somatotopic map” model, which suggests that somatosensory afferents are primarily organized by receptive field instead of modality. Using modality-specific genetic tracing, here we show that ascending mechanosensory and proprioceptive axons, two main types of the DDC afferents, are largely segregated into a medial–lateral pattern in the mouse dorsal column and medulla. In addition, we found that this modality-based organization is likely to be conserved in other mammalian species, including human. Furthermore, we identified key morphological differences between these two types of afferents, which explains how modality segregation is formed and why a rough “somatotopic map” was previously detected. Collectively, our results establish a new functional organization model for the mammalian direct dorsal column pathway and provide insight into how somatotopic and modality-based organization coexist in the central somatosensory pathway. PMID:24198362

  11. Distinct Excitation to Pulpal Stimuli between Somatosensory and Insular Cortices.

    PubMed

    Nakamura, H; Shirakawa, T; Koshikawa, N; Kobayashi, M

    2016-02-01

    Somatosensory information from the dental pulp is processed in the primary (S1) and secondary somatosensory cortex (S2) and in the insular oral region (IOR). Stimulation of maxillary incisor and molar initially induces excitation in S2/IOR, rostrodorsal to the mandibular incisor and molar pulp-responding regions. Although S1 and S2/IOR play their own roles in nociceptive information processing, the anatomical and physiological differences in the temporal activation kinetics, dependency on stimulation intensity, and additive or summative effects of simultaneous pulpal stimulation are still unknown. This information contributes not only to understanding topographical organization but also to speculating about the roles of S1 and S2/IOR in clinical aspects of pain regulation. In vivo optical imaging enables investigation of the spatiotemporal profiles of cortical excitation with high resolution. We determined the distinct features of optical responses to nociceptive stimulation of dental pulps between S1 and S2/IOR. In comparison to S1, optical signals in S2/IOR showed a larger amplitude with a shorter rise time and a longer decay time responding to maxillary molar pulp stimulation. The latency of excitation in S2/IOR was shorter than in S1. S2/IOR exhibited a lower threshold to evoke optical responses than S1, and the peak amplitude was larger in S2/IOR than in S1. Unexpectedly, the topography of S1 that responded to maxillary and mandibular incisor and molar pulps overlapped with the most ventral sites in S1 that was densely stained with cytochrome oxidase. An additive effect was observed in both S1 and S2/IOR after simultaneous stimulation of bilateral maxillary molar pulps but not after contralateral maxillary and mandibular molar pulp stimulation. These findings suggest that S2/IOR is more sensitive for detecting dental pulp sensation and codes stimulation intensity more precisely than S1. In addition, contra- and ipsilateral dental pulp nociception converges

  12. Dynamical activities of primary somatosensory cortices studied by magnetoencephalography

    NASA Astrophysics Data System (ADS)

    Kishida, Kuniharu

    2009-11-01

    A blind identification method of transfer functions in feedback systems is introduced for examination of dynamical activities of cortices by magnetoencephalography study. Somatosensory activities are examined in 5 Hz periodical median nerve stimulus. In the present paper, we will try two careful preprocessing procedures for the identification method to obtain impulse responses between primary somatosensory cortices. Time series data of the somatosensory evoked field are obtained by using a blind source separation of the T/k type (fractional) decorrelation method. Time series data of current dipoles of primary somatosensory cortices are transformed from the time series data of the somatosensory evoked field by the inverse problem. Fluctuations of current dipoles of them are obtained after elimination of deterministic periodical evoked waveforms. An identification method based on feedback system theory is used for estimation of transfer functions in a feedback model from obtained fluctuations of currents dipoles of primary somatosensory cortices. Dynamical activities between them are presented by Bode diagrams of transfer functions and their impulse responses: the time delay of about 30 ms via corpus callosum is found in the impulse response of identified transfer function.

  13. Spatio-temporal regulation of the formation of the somatosensory system.

    PubMed

    Kawasaki, Hiroshi

    2015-04-01

    The somatosensory system in the brain has been widely used for investigating the mechanisms underlying neural circuit formation and developmental neural plasticity. In the primary somatosensory cortex (S1) of rodents, there are discrete cytoarchitectonic units called barrels. Reverse genetic analyses using knockout mice have revealed molecules that control spatial pattern formation of barrels in S1. Glutamatergic receptors such as the NMDA receptor and mGluR5, and molecules related to serotonin such as serotonin transporter and monoamine oxidase A are essential for the formation of barrels. In addition to the mechanisms of spatial pattern formation, those regulating the timing of developmental processes were uncovered recently. Barrels are formed soon after the birth of newborn mouse pups from their mothers, and it was shown that the timing of barrel formation was determined by the timing of the birth of mouse pups. The mechanisms downstream of birth were also examined. It would be intriguing to examine if the mechanisms found using the somatosensory system are applicable to other brain regions.

  14. Skill-Specific Changes in Somatosensory Nogo Potentials in Baseball Players.

    PubMed

    Yamashiro, Koya; Sato, Daisuke; Onishi, Hideaki; Sugawara, Kazuhiro; Nakazawa, Sho; Shimojo, Hirofumi; Akatsuka, Kosuke; Nakata, Hiroki; Maruyama, Atsuo

    2015-01-01

    Athletic training is known to induce neuroplastic alterations in specific somatosensory circuits, which are reflected by changes in somatosensory evoked potentials and event-related potentials. The aim of this study was to clarify whether specific athletic training also affects somatosensory Nogo potentials related to the inhibition of movements. The Nogo potentials were recorded at nine cortical electrode positions (Fz, Cz, Pz, F3, F4, C3, C4, P3 and P4) in 12 baseball players (baseball group) and in 12 athletes in sports, such as track and field events and swimming, that do not require response inhibition, such as batting for training or performance (sports group). The Nogo potentials and Go/Nogo reaction times (Go/Nogo RTs) were measured under a somatosensory Go/Nogo paradigm in which subjects were instructed to rapidly push a button in response to stimulus presentation. The Nogo potentials were obtained by subtracting the Go trial from the Nogo trial. The peak Nogo-N2 was significantly shorter in the baseball group than that in the sports group. In addition, the amplitude of Nogo-N2 in the frontal area was significantly larger in the baseball group than that in the sports group. There was a significant positive correlation between the latency of Nogo-N2 and Go/Nogo RT. Moreover, there were significant correlations between the Go/Nogo RT and both the amplitude of Nogo-N2 and Nogo-P3 (i.e., amplitude of the Nogo-potentials increases with shorter RT). Specific athletic training regimens may induce neuroplastic alterations in sensorimotor inhibitory processes.

  15. Disordered plasticity in the primary somatosensory cortex in focal hand dystonia.

    PubMed

    Tamura, Yohei; Ueki, Yoshino; Lin, Peter; Vorbach, Sherry; Mima, Tatsuya; Kakigi, Ryusuke; Hallett, Mark

    2009-03-01

    Interventional paired associative stimulation (PAS) can induce plasticity in the cortex, and this plasticity was previously shown to be disordered in the primary motor cortex in focal hand dystonia (FHD). This study aimed to test whether associative plasticity is abnormal in the primary somatosensory cortex (S1) in FHD and whether PAS modulates excitatory or inhibitory interneurons within the cortex. Ten FHD patients and 10 healthy volunteers were studied. We investigated the changes in single- and double-pulse somatosensory-evoked potentials before and after PAS, which consisted of peripheral electrical nerve stimulation and subsequent transcranial magnetic stimulation over S1. Four sessions of somatosensory-evoked potentials recordings were performed: before PAS, and immediately, 15 and 30 min after PAS. We compared the time course of the somatosensory-evoked potentials between the FHD and healthy groups. In the single-pulse condition, the P27 amplitudes were significantly higher in FHD immediately after PAS than before PAS, while no changes were observed in healthy subjects. In the double-pulse condition, significant differences in the suppression ratio of P27 were found immediately after and 15 min after PAS, while there were no significant differences in healthy subjects. The P27 suppression tended to normalize toward the level of the healthy volunteer group. In FHD, PAS transiently induced an abnormal increase in excitability in S1. In addition, intracortical inhibition in S1 was found to increase as well. This abnormal plasticity of the intracortical neurons in S1 may contribute to the pathophysiology of dystonia. PMID:19151081

  16. Skill-Specific Changes in Somatosensory Nogo Potentials in Baseball Players

    PubMed Central

    Yamashiro, Koya; Sato, Daisuke; Onishi, Hideaki; Sugawara, Kazuhiro; Nakazawa, Sho; Shimojo, Hirofumi; Akatsuka, Kosuke; Nakata, Hiroki; Maruyama, Atsuo

    2015-01-01

    Athletic training is known to induce neuroplastic alterations in specific somatosensory circuits, which are reflected by changes in somatosensory evoked potentials and event-related potentials. The aim of this study was to clarify whether specific athletic training also affects somatosensory Nogo potentials related to the inhibition of movements. The Nogo potentials were recorded at nine cortical electrode positions (Fz, Cz, Pz, F3, F4, C3, C4, P3 and P4) in 12 baseball players (baseball group) and in 12 athletes in sports, such as track and field events and swimming, that do not require response inhibition, such as batting for training or performance (sports group). The Nogo potentials and Go/Nogo reaction times (Go/Nogo RTs) were measured under a somatosensory Go/Nogo paradigm in which subjects were instructed to rapidly push a button in response to stimulus presentation. The Nogo potentials were obtained by subtracting the Go trial from the Nogo trial. The peak Nogo-N2 was significantly shorter in the baseball group than that in the sports group. In addition, the amplitude of Nogo-N2 in the frontal area was significantly larger in the baseball group than that in the sports group. There was a significant positive correlation between the latency of Nogo-N2 and Go/Nogo RT. Moreover, there were significant correlations between the Go/Nogo RT and both the amplitude of Nogo-N2 and Nogo-P3 (i.e., amplitude of the Nogo-potentials increases with shorter RT). Specific athletic training regimens may induce neuroplastic alterations in sensorimotor inhibitory processes. PMID:26600391

  17. Molecular and cellular limits to somatosensory specificity

    PubMed Central

    Belmonte, Carlos; Viana, Félix

    2008-01-01

    Animals detect environmental changes through sensory neural mechanisms that enable them to differentiate the quality, intensity and temporal characteristics of stimuli. The 'doctrine of specific nervous energies' postulates that the different sensory modalities experienced by humans result of the activation of specific nervous pathways. Identification of functional classes of sensory receptors provided scientific support to the concept that somatosensory modalities (touch, pain, temperature, kinesthesis) are subserved by separate populations of sensory receptor neurons specialized in detecting innocuous and injurious stimuli of different quality (mechanical forces, temperature, chemical compounds). The identification of receptor proteins activated by different physicochemical stimuli, in particular ion channels of the Transient Receptor Potential (TRP) superfamily, has put forward the concept that specificity of peripheral sensory receptor neurons is determined by their expression of a particular "molecular sensor" that confers to each functional type its selectivity to respond with a discharge of nerve impulses to stimuli of a given quality. Nonetheless, recent experimental data suggest that the various molecular sensors proposed as specific transducer molecules for stimuli of different quality are not as neatly associated with the distinct functional types of sensory receptors as originally proposed. First, many ion channel molecules initially associated to the transduction of only one particular form of energy are also activated by stimuli of different quality, implying a limited degree of specificity in their transducing capacities. Second, molecular sensors associated with a stimulus quality and hence to a sensory receptor type and ultimately to a sensory modality may be concomitantly expressed in sensory receptor neurons functionally defined as specific for another stimulus quality. Finally, activation of voltage gated channels involved primarily in nerve

  18. Relationship between somatosensory deficit and brain somatosensory system after early brain lesion: A morphometric study.

    PubMed

    Perivier, Maximilien; Delion, Matthieu; Chinier, Eva; Loustau, Sebastien; Nguyen, Sylvie; Ter Minassian, Aram; Richard, Isabelle; Dinomais, Mickael

    2016-05-01

    Cerebral Palsy (CP) is a group of permanent motor disorders due to non-progressive damage to the developing brain. Poor tactile discrimination is common in children with unilateral CP. Previous findings suggest the crucial role of structural integrity of the primary (S1) and secondary (S2) somatosensory areas located in the ipsilesional hemisphere for somatosensory function processing. However, no focus on the relationship between structural characteristics of ipsilesional S1 and S2 and tactile discrimination function in paretic hands has been proposed. Using structural MRI and a two-point discrimination assessment (2 PD), we explore this potential link in a group of 21 children (mean age 13 years and 7 months) with unilateral CP secondary to a periventricular white matter injury (PWMI) or middle cerebral artery infarct (MCA). For our whole sample there was a significant negative correlation between the 2 PD and the gray matter volume in the ipsilesional S2 (rho = -0.50 95% confidence interval [-0.76, -0.08], one-tailed p-value = 0.0109) and in the ipsilesional S1 (rho = -0.57, 95% confidence interval [-0.81, -0.19], one-tailed p-value = 0.0032). When studying these relationships with regard to the lesion types, we found these correlations were non-significant in the patients with PWMI but stronger in patients with MCA. According to our results, the degree of sensory impairment is related to the spared gray matter volume in ipsilesional S1 and S2 and is marked after an MCA stroke. Our work contributes to a better understanding of why some patients with CP have variable somatosensory deficit following an early brain lesion. PMID:26831357

  19. Synaptic potentials evoked by convergent somatosensory and corticocortical inputs in raccoon somatosensory cortex: substrates for plasticity.

    PubMed

    Smits, E; Gordon, D C; Witte, S; Rasmusson, D D; Zarzecki, P

    1991-09-01

    1. "Unmasking" of weak synaptic connections has been suggested as a mechanism for the early changes in cortical topographic maps that follow alterations of sensory activity. For such a mechanism to operate, convergent sensory inputs must already exist in the normal cortex. 2. We tested for topographic and cross-modality convergence in primary somatosensory cortex of raccoon. The representation of glabrous skin of forepaw digits was chosen because, even though it is dominated by inputs from the glabrous skin of a single digit, it nevertheless comes to respond to stimulation of other digits when, e.g., a digit is removed. 3. Intracellular recordings were made from 109 neurons in the representation of glabrous skin of digit 4. Neurons were tested for somatosensory inputs with electrical and natural stimulation of digits. 4. Excitatory postsynaptic potentials (EPSPs) were evoked in 100% of the neurons (109/109) by electrical stimulation of glabrous skin of digit 4, and in 79% (31 of 39) by vibrotactile stimulation. 5. Glabrous skin of digit 4 was not the sole source of somatosensory inputs. A minority of neurons generated EPSPs after electrical stimulation of hairy skin of digit 4 (10 of 98 neurons, 10%). Electrical stimulation of digits 3 or 5 evoked EPSPs in 22 of 103 neurons (21%). Natural stimulation (vibrotactile or hair bending) was also effective in most of these latter cases (digit 3, 6/7; digit 5, 9/10). 6. Intracortical microstimulation of the "heterogeneous zone" was used to test for corticocortical connections to neurons in the glabrous zone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1753280

  20. Functional Plasticity in Somatosensory Cortex Supports Motor Learning by Observing.

    PubMed

    McGregor, Heather R; Cashaback, Joshua G A; Gribble, Paul L

    2016-04-01

    An influential idea in neuroscience is that the sensory-motor system is activated when observing the actions of others [1, 2]. This idea has recently been extended to motor learning, in which observation results in sensory-motor plasticity and behavioral changes in both motor and somatosensory domains [3-9]. However, it is unclear how the brain maps visual information onto motor circuits for learning. Here we test the idea that the somatosensory system, and specifically primary somatosensory cortex (S1), plays a role in motor learning by observing. In experiment 1, we applied stimulation to the median nerve to occupy the somatosensory system with unrelated inputs while participants observed a tutor learning to reach in a force field. Stimulation disrupted motor learning by observing in a limb-specific manner. Stimulation delivered to the right arm (the same arm used by the tutor) disrupted learning, whereas left arm stimulation did not. This is consistent with the idea that a somatosensory representation of the observed effector must be available during observation for learning to occur. In experiment 2, we assessed S1 cortical processing before and after observation by measuring somatosensory evoked potentials (SEPs) associated with median nerve stimulation. SEP amplitudes increased only for participants who observed learning. Moreover, SEPs increased more for participants who exhibited greater motor learning following observation. Taken together, these findings support the idea that motor learning by observing relies on functional plasticity in S1. We propose that visual signals about the movements of others are mapped onto motor circuits for learning via the somatosensory system.

  1. Validity of Clinically Derived Cumulative Somatosensory Impairment Index

    PubMed Central

    Deshpande, Nandini; Metter, E. Jeffrey; Ferrucci, Luigi

    2010-01-01

    Objective To develop a Cumulative Somatosensory Impairment Index for the lower limbs and evaluate its construct validity for discriminating relevant groups and predictive validity for predicting global postural control over time. Design Prospective cohort study. Setting Population-based cohort. Participants InCHIANTI (“Invecchiare in Chianti” or aging in the Chianti area) study participants (N=960; age, 21–91y, 51.8% women). Interventions Not applicable. Main Outcome Measures The Cumulative Somatosensory Impairment Index was derived from baseline performance on clinical tests of pressure sensitivity, vibration sensitivity, proprioception, and graphesthesia. Global postural control was assessed using Frailty and Injuries Cooperative Studies of Intervention Techniques (FICSIT) balance test, time to complete 5 repeated chair stands, and fast walking speed, at baseline and at 3-year follow-up. Results In participants without neurologic conditions (n=799), the Cumulative Somatosensory Impairment Index was significantly different in age groups classified by decades (P<.001). Compared with participants without prevalent conditions, the Cumulative Somatosensory Impairment Index was significantly higher in persons with diabetes (P=.017), peripheral arterial disease (P=.006), and a history of stroke (P<.001). In the overall population (N=960), in the fully adjusted multiple regression models, the Cumulative Somato-sensory Impairment Index independently predicted deterioration in FICSIT scores (P=.002), time for 5 repeated chair stands (P<.001), and fast gait speed (P=.003) at 3-year follow-up. Conclusions The Cumulative Somatosensory Impairment Index is a valid measure that detects relevant group differences in lower limb somatosensory impairment and is an independent predictor of decline in postural control over 3 years. PMID:20159126

  2. Functional Plasticity in Somatosensory Cortex Supports Motor Learning by Observing.

    PubMed

    McGregor, Heather R; Cashaback, Joshua G A; Gribble, Paul L

    2016-04-01

    An influential idea in neuroscience is that the sensory-motor system is activated when observing the actions of others [1, 2]. This idea has recently been extended to motor learning, in which observation results in sensory-motor plasticity and behavioral changes in both motor and somatosensory domains [3-9]. However, it is unclear how the brain maps visual information onto motor circuits for learning. Here we test the idea that the somatosensory system, and specifically primary somatosensory cortex (S1), plays a role in motor learning by observing. In experiment 1, we applied stimulation to the median nerve to occupy the somatosensory system with unrelated inputs while participants observed a tutor learning to reach in a force field. Stimulation disrupted motor learning by observing in a limb-specific manner. Stimulation delivered to the right arm (the same arm used by the tutor) disrupted learning, whereas left arm stimulation did not. This is consistent with the idea that a somatosensory representation of the observed effector must be available during observation for learning to occur. In experiment 2, we assessed S1 cortical processing before and after observation by measuring somatosensory evoked potentials (SEPs) associated with median nerve stimulation. SEP amplitudes increased only for participants who observed learning. Moreover, SEPs increased more for participants who exhibited greater motor learning following observation. Taken together, these findings support the idea that motor learning by observing relies on functional plasticity in S1. We propose that visual signals about the movements of others are mapped onto motor circuits for learning via the somatosensory system. PMID:26972317

  3. Multivariate analysis of somatosensory evoked potential parameters in normal adults.

    PubMed

    Strenge, H; Gundel, A

    1983-01-01

    Cervical and cortical somatosensory evoked potentials (SEP) to median nerve stimulation were recorded in 65 normal subjects. Absolute peak latencies and amplitudes of cervical components N9, P10, N11, N13, P17, and cortical components P16, N20, P25, and N35 were measured. By means of partial correlations the interdependency of SEP-features could be verified in addition to the well-known dependence on arm length and age. In certain respects our results replicate other studies finding significant correlations between age and latency of early SEP-components as well as inverse relations between age and cervical amplitudes. Further analysis disclosed high inter-correlations between the latencies and between the amplitudes of the cervical and cortical components also revealing a certain exceptional position of the positive wave P17. In contrast to an inverse relation of amplitude and latency of the cervical components there were positive correlations between the respective features in the cortical evoked response. The findings are discussed with regard to the current knowledge about the origins of the SEP-components. PMID:6667105

  4. Combined dermal exposure to permethrin and cis-urocanic acid suppresses the contact hypersensitivity response in C57BL/6N mice in an additive manner.

    PubMed

    Prater, M R; Blaylock, B L; Holladay, S D

    2005-01-14

    Cutaneous exposure to the pyrethroid insecticide permethrin significantly suppresses contact hypersensitivity (CH) response to oxazolone in C57BL/6N mice. Additionally, cis-urocanic acid (cUCA), an endogenous cutaneous chromophore isomerized to its active form following exposure to ultraviolet radiation, modulates cell-mediated cutaneous immune responses. This study describes cutaneous immune alterations following combined topical permethrin and intradermal cUCA exposure. Female C57BL/6N mice were administered 5, 50 or 100 microg cUCA daily for 5 consecutive days. CH was then evaluated by the mouse ear swelling test (MEST) response to oxazolone. Decreased responses of 52.3%, 76.3% and 76.3%, respectively, as compared to controls were observed. Then, mice were co-exposed to 5 microg cUCA daily for 5 days and 1.5, 5, 15, or 25 microL permethrin, on either day 1, 3 or 5 of the cUCA treatment to evaluate combined immunomodulatory effects of the two chemicals, or cUCA daily for 5 days followed by permethrin on day 3, 5, or 7 after the last cUCA injection to demonstrate prolonged immunosuppressive effects. Two days after final treatment, mice were sensitized with oxazolone and MEST was performed. Mice receiving five cUCA injections and permethrin topically on cUCA injection day 1 showed up to 93.3% suppression of MEST compared to vehicle control. CH was suppressed by 87.5%, 86.6% and 74.2% in mice treated with 25 muL permethrin on days 3, 5 and 7 after cUCA, respectively, compared to vehicle control. Taken together, these data indicate co-exposure to cUCA and permethrin profoundly suppresses cell-mediated cutaneous immunity. PMID:15629246

  5. [The cerebral control of the somatosensory and auditory afferent projections to the cerebral cortex in man and animals].

    PubMed

    Liubimov, N N; Orlova, T V; Liubimov, S N

    1998-01-01

    The main purpose of the present paper was consisted in studying of topology (spreading) of the somatosensory and auditory projections in cortex of both brain hemispheres in humans under different functional states conditions: during quiet walking state and during realization of the meditative programme. At the same time for the purpose of verification these steering mechanisms a number of experiments were realized in animals with neurosurgical cutting of brainstem ascending projections, which control the transfer of somatosensory and auditory sensibility. Experimental study was realized with two groups of subjects--8 subjects (age from 25 to 35 years old) and 25 (age from 25 to 40 years old) subjects practicing technique of Transcendental Meditation (TM). In addition to the mentioned above group some groups of animals were used in the experiments. Among them there were used the groups of monkeys (8 macaque rhesus and macaque nemestrina) and cats (10 animals) in conditions of acute experiment, under tiopenthal anesthesia. Two experimental methods were used in the study: electrophysiological for subjects and neurosurgical, additionally for animals. For evaluation of the brain reactivity in subjects registration of the somatosensory, to median nerve stimulation, and auditory, to bilateral application of auditory clicks, evoked potentials (EPs) in the symmetrical cortical structures of the brain was used. Registration of the somatosensory and auditory evoked potentials in animals was realized not only from the cortex, but from the brainstem somatosensory and auditory structures. SSEP in subjects-meditators were registered before and during meditation programme. In animals SSEP and AEP registration on the corresponding stimuli realized before and after neurosurgical operation--section of the midbrain tegmentum. Specific alterations of the early (up to 80 ms) and late components SSEP and AEP complexes in forms of topology spreading and diminution of registration areas of

  6. Somatosensory Findings of Pusher Syndrome in Stroke Patients

    PubMed Central

    Lee, Jong Hwa; Kim, Sang Beom; Lee, Kyeong Woo

    2013-01-01

    Objective To investigate the somatosensory findings of pusher syndrome in stroke patients. Methods Twelve pusher patients and twelve non-pusher patients were enrolled in this study. Inclusion criteria were unilateral stroke, sufficient cognitive abilities to understand and follow instructions, and no visual problem. Patients were evaluated for pusher syndrome using a standardized scale for contraversive pushing. Somatosensory finding was assessed by the Cumulative Somatosensory Impairment Index (CSII) and somatosensory evoked potentials (SEPs) at 1 and 14 weeks after the stroke onset. Data of SEPs with median and tibial nerve stimulation were classified into the normal, abnormal, and no response group. Results In the baseline characteristics (sex, lesion character, and side) of both groups, significant differences were not found. The score of CSII decreased in both groups at 14 weeks (p<0.05), but there were no significant differences in the CSII scores between the two groups at 1 and 14 weeks. There were no significant differences in SEPs between the two groups at 1 and 14 weeks after the stroke onset. Conclusion It appears that somatosensory input plays a relatively minor role in pusher syndrome. Further study will be required to reveal the mechanism of pusher syndrome. PMID:23525623

  7. Functional deficits in carpal tunnel syndrome reflect reorganization of primary somatosensory cortex

    PubMed Central

    Kettner, Norman; Holden, Jameson; Lee, Jeungchan; Kim, Jieun; Cina, Stephen; Malatesta, Cristina; Gerber, Jessica; McManus, Claire; Im, Jaehyun; Libby, Alexandra; Mezzacappa, Pia; Morse, Leslie R.; Park, Kyungmo; Audette, Joseph; Tommerdahl, Mark; Napadow, Vitaly

    2014-01-01

    Carpal tunnel syndrome, a median nerve entrapment neuropathy, is characterized by sensorimotor deficits. Recent reports have shown that this syndrome is also characterized by functional and structural neuroplasticity in the primary somatosensory cortex of the brain. However, the linkage between this neuroplasticity and the functional deficits in carpal tunnel syndrome is unknown. Sixty-three subjects with carpal tunnel syndrome aged 20–60 years and 28 age- and sex-matched healthy control subjects were evaluated with event-related functional magnetic resonance imaging at 3 T while vibrotactile stimulation was delivered to median nerve innervated (second and third) and ulnar nerve innervated (fifth) digits. For each subject, the interdigit cortical separation distance for each digit’s contralateral primary somatosensory cortex representation was assessed. We also evaluated fine motor skill performance using a previously validated psychomotor performance test (maximum voluntary contraction and visuomotor pinch/release testing) and tactile discrimination capacity using a four-finger forced choice response test. These biobehavioural and clinical metrics were evaluated and correlated with the second/third interdigit cortical separation distance. Compared with healthy control subjects, subjects with carpal tunnel syndrome demonstrated reduced second/third interdigit cortical separation distance (P < 0.05) in contralateral primary somatosensory cortex, corroborating our previous preliminary multi-modal neuroimaging findings. For psychomotor performance testing, subjects with carpal tunnel syndrome demonstrated reduced maximum voluntary contraction pinch strength (P < 0.01) and a reduced number of pinch/release cycles per second (P < 0.05). Additionally, for four-finger forced-choice testing, subjects with carpal tunnel syndrome demonstrated greater response time (P < 0.05), and reduced sensory discrimination accuracy (P < 0.001) for median nerve, but not ulnar nerve

  8. Beta oscillations define discrete perceptual cycles in the somatosensory domain

    PubMed Central

    Baumgarten, Thomas J.; Schnitzler, Alfons; Lange, Joachim

    2015-01-01

    Whether seeing a movie, listening to a song, or feeling a breeze on the skin, we coherently experience these stimuli as continuous, seamless percepts. However, there are rare perceptual phenomena that argue against continuous perception but, instead, suggest discrete processing of sensory input. Empirical evidence supporting such a discrete mechanism, however, remains scarce and comes entirely from the visual domain. Here, we demonstrate compelling evidence for discrete perceptual sampling in the somatosensory domain. Using magnetoencephalography (MEG) and a tactile temporal discrimination task in humans, we find that oscillatory alpha- and low beta-band (8–20 Hz) cycles in primary somatosensory cortex represent neurophysiological correlates of discrete perceptual cycles. Our results agree with several theoretical concepts of discrete perceptual sampling and empirical evidence of perceptual cycles in the visual domain. Critically, these results show that discrete perceptual cycles are not domain-specific, and thus restricted to the visual domain, but extend to the somatosensory domain. PMID:26324922

  9. Roll-Tilt Perception Using a Somatosensory Bar Task

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Wade, S. W.; Arshi, A.

    1999-01-01

    Visual estimates of roll-tilt perception during static roll-tilt are confounded by an offset due to the ocular counterroll that simultaneously occurs. An alternative, non-visual ('somatosensory') measure of roll-tilt perception was developed which is not contaminated by this offset. The aims of this study were to determine: 1) inter-subject variability of somatosensory settings across test session in normal subjects and patients with unilateral or bilateral vestibular loss and 2) intra-subject variability of settings across test session in normal subjects.

  10. Simultaneous Top-down Modulation of the Primary Somatosensory Cortex and Thalamic Nuclei during Active Tactile Discrimination

    PubMed Central

    Pais-Vieira, Miguel; Lebedev, Mikhail A.; Wiest, Michael C.; Nicolelis, Miguel A.L.

    2013-01-01

    The rat somatosensory system contains multiple thalamocortical loops (TCL) that altogether process, in fundamentally different ways, tactile stimuli delivered passively or actively sampled. To elucidate potential top-down mechanisms that govern TCL processing in awake, behaving animals, we simultaneously recorded neuronal ensemble activity across multiple cortical and thalamic areas while rats performed an active aperture discrimination task. Single neurons located in the primary somatosensory cortex (S1), the ventroposterior medial (VPM) and the posterior medial (POM) thalamic nuclei of the trigeminal somatosensory pathways exhibited prominent anticipatory firing modulations prior to the whiskers touching the aperture edges. This cortical and thalamic anticipatory firing could not be explained by whisker movements or whisker stimulation, because neither trigeminal ganglion sensory-evoked responses nor EMG activity were detected during the same period. Both thalamic and S1 anticipatory activity were predictive of the animal’s discrimination accuracy. Inactivation of the primary motor cortex (M1) with muscimol affected anticipatory patterns in S1 and the thalamus, and impaired the ability to predict the animal’s performance accuracy based on thalamocortical anticipatory activity. These findings suggest that neural processing in TCLs is launched in anticipation of whisker contact with objects, depends on top-down effects generated in part by M1 activity, and cannot be explained by the classical feedforward model of the rat trigeminal system. PMID:23447616

  11. Neural mechanisms of selective attention in the somatosensory system.

    PubMed

    Gomez-Ramirez, Manuel; Hysaj, Kristjana; Niebur, Ernst

    2016-09-01

    Selective attention allows organisms to extract behaviorally relevant information while ignoring distracting stimuli that compete for the limited resources of their central nervous systems. Attention is highly flexible, and it can be harnessed to select information based on sensory modality, within-modality feature(s), spatial location, object identity, and/or temporal properties. In this review, we discuss the body of work devoted to understanding mechanisms of selective attention in the somatosensory system. In particular, we describe the effects of attention on tactile behavior and corresponding neural activity in somatosensory cortex. Our focus is on neural mechanisms that select tactile stimuli based on their location on the body (somatotopic-based attention) or their sensory feature (feature-based attention). We highlight parallels between selection mechanisms in touch and other sensory systems and discuss several putative neural coding schemes employed by cortical populations to signal the behavioral relevance of sensory inputs. Specifically, we contrast the advantages and disadvantages of using a gain vs. spike-spike correlation code for representing attended sensory stimuli. We favor a neural network model of tactile attention that is composed of frontal, parietal, and subcortical areas that controls somatosensory cells encoding the relevant stimulus features to enable preferential processing throughout the somatosensory hierarchy. Our review is based on data from noninvasive electrophysiological and imaging data in humans as well as single-unit recordings in nonhuman primates. PMID:27334956

  12. Topography of somatosensory processing: cerebral lateralization and focused attention.

    PubMed

    Meador, K J; Allison, J D; Loring, D W; Lavin, T B; Pillai, J J

    2002-03-01

    Healthy dextrals underwent fMRI during a task of graphesthesia requiring detection of any number written consecutively from an otherwise random number sequence. Test conditions included (1) focus on unilateral right hand stimuli, (2) focus on unilateral left hand stimuli, (3) focus on right hand only during bilateral hand stimulation, (4) focus on left hand only during bilateral hand stimulation, and (5) rest. Attention to unilateral hand stimulation produced bihemispheric activation with minimal or no activation of ipsilateral primary sensorimotor region. Attention to unilateral left hand stimuli resulted in more activation than attention to unilateral right hand stimuli. Stimulation of the nonattended hand activated the contralateral somatosensory area, but to a lesser spatial extent than attended stimuli. Comparing focused attention to the left versus right side during identical sensory inputs (i.e., bilateral hand stimulation), focused attention to the right hand increased activation in the left somatosensory region, but focused attention to the left hand increased activation in both cerebral hemispheres. Thus, focused attention to unilateral somatosensory stimuli produces bilateral cerebral activation, but the increase in blood flow is greater in the contralateral hemisphere. Unattended stimuli activate the contralateral primary somatosensory area. Left/right asymmetries were demonstrated consistent with cerebral lateralization.

  13. Somatosensory evoked magnetic fields in patients with stroke.

    PubMed

    Maclin, E L; Rose, D F; Knight, J E; Orrison, W W; Davis, L E

    1994-12-01

    We used magnetoencephalography to evaluate areas of sensory cortex in patients with ischemic strokes involving the somatomotor system. We measured somatosensory evoked magnetic fields using a 7-channel neuromagnetometer and estimated the location of cortical responses to median nerve stimulation in 5 patients with cortical or subcortical strokes involving the somatomotor system. All patients underwent quantitative neurological examinations and a high resolution volumetric magnetic resonance imaging. The estimated current dipoles were localized onto the patient's own MRI scan in all patients with measurable responses. The location of the estimated dipole was always in non-infarcted tissue in the anatomical region of the somatosensory cortex. In 1 patient the somatosensory dipole localized to a peninsula of cortex flanked by infarcted tissue. Single photon emission computed tomography found the localized area of cortex to have significant blood flow. The estimated current dipole strengths of somatosensory evoked fields from median nerve stimulation correlated significantly (r = 0.95, P < 0.02) with the patient's ability to recognize numbers written on the involved palm (graphesthesia). The combination of evoked magnetic field recording and magnetic resonance imaging is a promising non-invasive technology for studying brain function in patients with cerebrovascular disease.

  14. Composition, diffusion, and antifungal activity of black mustard (Brassica nigra) essential oil when applied by direct addition or vapor phase contact.

    PubMed

    Mejía-Garibay, Beatriz; Palou, Enrique; López-Malo, Aurelio

    2015-04-01

    In this study, we characterized the essential oil (EO) of black mustard (Brassica nigra) and quantified its antimicrobial activity, when applied by direct contact into the liquid medium or by exposure in the vapor phase (in laboratory media or in a bread-type product), against the growth of Aspergillus niger, Aspergillus ochraceus, or Penicillium citrinum. Allyl-isothiocyanate (AITC) was identified as the major component of B. nigra EO with a concentration of 378.35 mg/ml. When B. nigra EO was applied by direct contact into the liquid medium, it inhibited the growth of A. ochraceus and P. citrinum when the concentration was 2 μl/ml of liquid medium (MIC), while for A. niger, a MIC of B. nigra EO was 4 μl/ml of liquid medium. Exposure of molds to B. nigra EO in vapor phase showed that 41.1 μl of B. nigra EO per liter of air delayed the growth of P. citrinum and A. niger by 10 days, while A. ochraceus growth was delayed for 20 days. Exposure to concentrations ≥ 47 μl of B. nigra EO per liter of air (MIC) inhibited the growth of tested molds by 30 days, and they were not able to recover after further incubation into an environment free of EO (fungicidal effect). Adsorbed AITC was quantified by exposing potato dextrose agar to B. nigra EO in a vapor phase, exhibiting that AITC was retained at least 5 days when testing EO at its MIC or with higher concentrations. Mustard EO MIC was also effective against the evaluated molds inhibiting their growth for 30 days in a bread-type product when exposed to EO by vapor contact, demonstrating its antifungal activity.

  15. Composition, diffusion, and antifungal activity of black mustard (Brassica nigra) essential oil when applied by direct addition or vapor phase contact.

    PubMed

    Mejía-Garibay, Beatriz; Palou, Enrique; López-Malo, Aurelio

    2015-04-01

    In this study, we characterized the essential oil (EO) of black mustard (Brassica nigra) and quantified its antimicrobial activity, when applied by direct contact into the liquid medium or by exposure in the vapor phase (in laboratory media or in a bread-type product), against the growth of Aspergillus niger, Aspergillus ochraceus, or Penicillium citrinum. Allyl-isothiocyanate (AITC) was identified as the major component of B. nigra EO with a concentration of 378.35 mg/ml. When B. nigra EO was applied by direct contact into the liquid medium, it inhibited the growth of A. ochraceus and P. citrinum when the concentration was 2 μl/ml of liquid medium (MIC), while for A. niger, a MIC of B. nigra EO was 4 μl/ml of liquid medium. Exposure of molds to B. nigra EO in vapor phase showed that 41.1 μl of B. nigra EO per liter of air delayed the growth of P. citrinum and A. niger by 10 days, while A. ochraceus growth was delayed for 20 days. Exposure to concentrations ≥ 47 μl of B. nigra EO per liter of air (MIC) inhibited the growth of tested molds by 30 days, and they were not able to recover after further incubation into an environment free of EO (fungicidal effect). Adsorbed AITC was quantified by exposing potato dextrose agar to B. nigra EO in a vapor phase, exhibiting that AITC was retained at least 5 days when testing EO at its MIC or with higher concentrations. Mustard EO MIC was also effective against the evaluated molds inhibiting their growth for 30 days in a bread-type product when exposed to EO by vapor contact, demonstrating its antifungal activity. PMID:25836415

  16. Functional Reorganization of the Primary Somatosensory Cortex of a Phantom Limb Pain Patient.

    PubMed

    Zhao, Jia; Guo, Xiaoli; Xia, Xiaolei; Peng, Weiwei; Wang, Wuchao; Li, Shulin; Zhang, Ya; Hu, Li

    2016-07-01

    Functional reorganization of the somatosensory system was widely observed in phantom limb pain patients. Whereas some studies demonstrated that the primary somatosensory cortex (S1) of the amputated limb was engaged with the regions around it, others showed that phantom limb pain was associated with preserved structure and functional organization in the former brain region. However, according to the law of use and disuse, the sensitivity of S1 of the amputated limb to pain-related context should be enhanced due to the adaptation to the long-lasting phantom limb pain experience. Here, we collected neurophysiological data from a patient with 21-year phantom limb pain using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) techniques. EEG data showed that both laser-evoked potentials (LEPs) and tactile-evoked potentials (TEPs) were clearly presented only when radiant-heat laser pulses and electrical pulses were delivered to the shoulder of the healthy limb, but not of the amputated limb. This observation suggested the functional deficit of somatosensory pathways at the amputated side. FMRI data showed that significant larger brain activations by painful rather than non-painful stimuli in video clips were observed not only at visual-related brain areas and anterior/mid-cingulate cortex, but also at S1 contralateral to the amputated limb. This observation suggested the increased sensitivity of S1 of the amputated limb to the pain-related context. In addition, such increase of sensitivity was significantly larger if the context was associated with the amputated limb of the patient. In summary, our findings provided novel evidence for a possible neuroplasticity of S1 of the amputated limb: in an amputee with long-lasting phantom limb pain, the sensitivity of S1 to pain-related and amputated-limb-related context was greatly enhanced. PMID:27389122

  17. Contact Dermatitis

    MedlinePlus

    ... care Kids’ zone Video library Find a dermatologist Contact dermatitis Overview Contact dermatitis: Many health care workers ... to touching her face while wearing latex gloves. Contact dermatitis: Overview Almost everyone gets this type of ...

  18. Language Contact.

    ERIC Educational Resources Information Center

    Nelde, Peter Hans

    1995-01-01

    Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

  19. Contact reactions to food.

    PubMed

    Killig, Claudia; Werfel, Thomas

    2008-05-01

    Cutaneous adverse reactions to foods, spices, and food additives can occur both in occupational and nonoccupational settings in those who grow, handle, prepare, or cook food. Because spices are also utilized in cosmetics and perfumes, other exposures are encountered that can result in adverse cutaneous reactions. This article describes the reaction patterns that can occur upon contact with foods, including irritant contact dermatitis and allergic contact dermatitis. The ingestion of culprit foods by sensitized individuals can provoke a generalized eczematous rash, referred to as systemic contact dermatitis. Other contact reactions to food include contact urticaria and protein contact dermatitis provoked by high-molecular-weight food proteins often encountered in patients with atopic dermatitis. Phototoxic and photoallergic contact dermatitis are also considered.

  20. Human high frequency somatosensory evoked potential components are refractory to circadian modulations of tonic alertness.

    PubMed

    Gobbelé, René; Waberski, Till D; Thyerlei, Dinah; Thissen, Melanie; Fimm, Bruno; Klostermann, Fabian; Curio, Gabriel; Buchner, Helmut

    2007-02-01

    The impact of vigilance states, such as sleep or arousal changes, on the high-frequency (600 Hz) components (HFOs) of somatosensory evoked potentials (SEPs) is known. The present study sought to characterize the effects of circadian fluctuations of tonic alertness on HFOs in awake humans. Median nerve SEPs were recorded at four times during a 24-hour waking period. In parallel to the SEP recordings, a reaction-time (RT) task was performed to assess tonic alertness. Additionally, the spontaneous EEG was monitored. The low-frequency SEP component N20 and the early and late HFO parts did not change across the measurement sessions. In contrast, RTs were clearly prolonged at night and on the second morning. EEG also showed increased delta power at night. HFOs are sensitive to pronounced vigilance changes, such as sleep, but are refractory to fluctuations of tonic alertness. Tonic alertness is regarded to be the top-down cognitive control mechanism of wakefulness, whereas sleep is mediated by overwhelming bottom-up regulation, which seems apparently more relevant for, at least in part, subcortically triggered high-frequency burst generation in the ascending somatosensory system. PMID:17277574

  1. Resting BOLD fluctuations in the primary somatosensory cortex correlate with tactile acuity.

    PubMed

    Haag, Lauren M; Heba, Stefanie; Lenz, Melanie; Glaubitz, Benjamin; Höffken, Oliver; Kalisch, Tobias; Puts, Nicholaas A; Edden, Richard A E; Tegenthoff, Martin; Dinse, Hubert; Schmidt-Wilcke, Tobias

    2015-03-01

    Sensory perception, including 2-point discrimination (2 ptD), is tightly linked to cortical processing of tactile stimuli in primary somatosensory cortices. While the role of cortical activity in response to a tactile stimulus has been widely investigated, the role of baseline cortical activity is largely unknown. Using resting state fMRI we investigated the relationship between local BOLD fluctuations in the primary somatosensory cortex (the representational field of the hand) and 2 ptD of the corresponding index finger (right and left). Cortical activity was measured using fractional amplitudes of the low frequency BOLD fluctuations (fALFF) and synchronicity using regional homogeneity (ReHo) of the S1 hand region during rest. 2 ptD correlated with higher ReHo values in the representational areas of the contralateral S1 cortex (left hand: p = .028; right hand: p = .049). 2 ptD additionally correlated with higher fALFF in the representational area of the left hand (p = .007) and showed a trend for a significant correlation in the representational area of the right hand (p = .051). Thus, higher BOLD amplitudes and synchronicity at rest, as measures of cortical activity and synchronicity, respectively, are related to better tactile discrimination abilities of the contralateral hand. Our findings extend the relationship seen between spontaneous BOLD fluctuations and sensory perception.

  2. Pathway-specific reorganization of projection neurons in somatosensory cortex during learning.

    PubMed

    Chen, Jerry L; Margolis, David J; Stankov, Atanas; Sumanovski, Lazar T; Schneider, Bernard L; Helmchen, Fritjof

    2015-08-01

    In the mammalian brain, sensory cortices exhibit plasticity during task learning, but how this alters information transferred between connected cortical areas remains unknown. We found that divergent subpopulations of cortico-cortical neurons in mouse whisker primary somatosensory cortex (S1) undergo functional changes reflecting learned behavior. We chronically imaged activity of S1 neurons projecting to secondary somatosensory (S2) or primary motor (M1) cortex in mice learning a texture discrimination task. Mice adopted an active whisking strategy that enhanced texture-related whisker kinematics, correlating with task performance. M1-projecting neurons reliably encoded basic kinematics features, and an additional subset of touch-related neurons was recruited that persisted past training. The number of S2-projecting touch neurons remained constant, but improved their discrimination of trial types through reorganization while developing activity patterns capable of discriminating the animal's decision. We propose that learning-related changes in S1 enhance sensory representations in a pathway-specific manner, providing downstream areas with task-relevant information for behavior.

  3. The Cortical Signature of Central Poststroke Pain: Gray Matter Decreases in Somatosensory, Insular, and Prefrontal Cortices.

    PubMed

    Krause, T; Asseyer, S; Taskin, B; Flöel, A; Witte, A V; Mueller, K; Fiebach, J B; Villringer, K; Villringer, A; Jungehulsing, G J

    2016-01-01

    It has been proposed that cortical structural plasticity plays a crucial role in the emergence and maintenance of chronic pain. Various distinct pain syndromes have accordingly been linked to specific patterns of decreases in regional gray matter volume (GMV). However, it is not known whether central poststroke pain (CPSP) is also associated with cortical structural plasticity. To determine this, we employed T1-weighted magnetic resonance imaging at 3 T and voxel-based morphometry in 45 patients suffering from chronic subcortical sensory stroke with (n = 23) and without CPSP (n = 22), and healthy matched controls (n = 31). CPSP patients showed decreases in GMV in comparison to healthy controls, involving secondary somatosensory cortex (S2), anterior as well as posterior insular cortex, ventrolateral prefrontal and orbitofrontal cortex, temporal cortex, and nucleus accumbens. Comparing CPSP patients to nonpain patients revealed a similar but more restricted pattern of atrophy comprising S2, ventrolateral prefrontal and temporal cortex. Additionally, GMV in the ventromedial prefrontal cortex negatively correlated to pain intensity ratings. This shows for the first time that CPSP is accompanied by a unique pattern of widespread structural plasticity, which involves the sensory-discriminative areas of insular/somatosensory cortex, but also expands into prefrontal cortex and ventral striatum, where emotional aspects of pain are processed.

  4. Somatosensory inputs modify auditory spike timing in dorsal cochlear nucleus principal cells

    PubMed Central

    Koehler, Seth D; Pradhan, Shashwati; Manis, Paul B; Shore, Susan E

    2010-01-01

    In addition to auditory inputs, dorsal cochlear nucleus (DCN) pyramidal cells in the guinea pig receive and respond to somatosensory inputs and perform multisensory integration. DCN pyramidal cells respond to sounds with characteristic spike-timing patterns that are partially controlled by rapidly inactivating potassium conductances. Deactivating these conductances can modify both spike rate and spike timing of responses to sound. Somatosensory pathways are known to modify response rates to subsequent acoustic stimuli, but their effect on spike timing is unknown. Here, we demonstrate that preceding tonal stimulation with spinal trigeminal nucleus (Sp5) stimulation significantly alters the first spike latency, the first interspike interval, and the average discharge regularity of firing evoked by the tone. These effects occur whether the neuron is excited or inhibited by Sp5 stimulation alone. Our results demonstrate that multisensory integration in DCN alters spike-timing representations of acoustic stimuli in pyramidal cells. These changes likely occur through synaptic modulation of intrinsic excitability or synaptic inhibition. PMID:21198989

  5. Diagnosis and management of somatosensory tinnitus: review article

    PubMed Central

    Sanchez, Tanit Ganz; Rocha, Carina Bezerra

    2011-01-01

    Tinnitus is the perception of sound in the absence of an acoustic external stimulus. It affects 10–17% of the world's population and it a complex symptom with multiple causes, which is influenced by pathways other than the auditory one. Recently, it has been observed that tinnitus may be provoked or modulated by stimulation arising from the somatosensorial system, as well as from the somatomotor and visual–motor systems. This specific subgroup – somatosensory tinnitus – is present in 65% of cases, even though it tends to be underdiagnosed. As a consequence, it is necessary to establish evaluation protocols and specific treatments focusing on both the auditory pathway and the musculoskeletal system. PMID:21808880

  6. A somatosensory circuit for cooling perception in mice.

    PubMed

    Milenkovic, Nevena; Zhao, Wen-Jie; Walcher, Jan; Albert, Tobias; Siemens, Jan; Lewin, Gary R; Poulet, James F A

    2014-11-01

    The temperature of an object provides important somatosensory information for animals performing tactile tasks. Humans can perceive skin cooling of less than one degree, but the sensory afferents and central circuits that they engage to enable the perception of surface temperature are poorly understood. To address these questions, we examined the perception of glabrous skin cooling in mice. We found that mice were also capable of perceiving small amplitude skin cooling and that primary somatosensory (S1) cortical neurons were required for cooling perception. Moreover, the absence of the menthol-gated transient receptor potential melastatin 8 ion channel in sensory afferent fibers eliminated the ability to perceive cold and the corresponding activation of S1 neurons. Our results identify parts of a neural circuit underlying cold perception in mice and provide a new model system for the analysis of thermal processing and perception and multimodal integration.

  7. Neural coding and perceptual detection in the primate somatosensory thalamus.

    PubMed

    Vázquez, Yuriria; Zainos, Antonio; Alvarez, Manuel; Salinas, Emilio; Romo, Ranulfo

    2012-09-11

    The contribution of the sensory thalamus to perception and decision making is not well understood. We addressed this problem by recording single neurons in the ventral posterior lateral (VPL) nucleus of the somatosensory thalamus while trained monkeys judged the presence or absence of a vibrotactile stimulus of variable amplitude applied to the skin of a fingertip. We found that neurons in the VPL nucleus modulated their firing rate as a function of stimulus amplitude, and that such modulations accounted for the monkeys' overall psychophysical performance. These neural responses did not predict the animals' decision reports in individual trials, however. Moreover, the sensitivity to changes in stimulus amplitude was similar when the monkeys' performed the detection task and when they were not required to report stimulus detection. These results suggest that the primate somatosensory thalamus likely provides a reliable neural representation of the sensory input to the cerebral cortex, where sensory information is transformed and combined with other cognitive components associated with behavioral performance.

  8. Effects of passive heat stress on human somatosensory processing.

    PubMed

    Nakata, Hiroki; Oshiro, Misaki; Namba, Mari; Shibasaki, Manabu

    2015-12-01

    Herein, we investigated the effects of passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs). Fifteen healthy subjects received a median nerve stimulation at the left wrist under two thermal conditions: Heat Stress and normothermic Time Control. The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4' and P14, N18, P22, and N30 at Fz were evaluated. Under the Heat Stress condition, SEPs were recorded at normothermic baseline (1st), early in heat stress (2nd), when esophageal temperature had increased by ~1.0°C (3rd) and ~2.0°C (4th), and after heat stress (5th). In the Time Control condition, SEPs were measured at the same time intervals as those in the Heat Stress condition. The peak latencies and amplitudes of SEPs did not change early in heat stress. However, the latencies of P14, N20, and N60 at C4' and P14, N18, and P22 at Fz were significantly shorter in the 4th session than in the 1st session. Furthermore, the peak amplitudes of P25 and N60 at C4', and P22 and N30 at Fz decreased with increases in body temperature. On the other hand, under the Time Control condition, no significant differences were observed in the amplitudes or latencies of any component of SEPs. These results suggested that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and hyperthermia impaired the neural activity of cortical somatosensory processing. PMID:26468258

  9. Are There Abnormalities in Peripheral and Central Components of Somatosensory Evoked Potentials in Non-Specific Chronic Low Back Pain?

    PubMed Central

    Puta, Christian; Franz, Marcel; Blume, Kathrin R.; Gabriel, Holger H. W.; Miltner, Wolfgang H. R.; Weiss, Thomas

    2016-01-01

    Chronic low back pain (CLBP) was shown to be associated with longer reflex response latencies of trunk muscles during external upper limb perturbations. One theoretical, but rarely investigated possibility for longer reflex latencies might be related to modulated somatosensory information processing. Therefore, the present study investigated somatosensory evoked potentials (SEPs) to median nerve stimulation in CLBP patients and healthy controls (HC). Latencies of the peripheral N9 SEP component were used as the primary outcome. In addition, latencies and amplitudes of the central N20 SEP component, sensory thresholds, motor thresholds and nerve conduction velocity were also analyzed in CLBP patients and HC. There is a trend for the CLBP patients to exhibit longer N9 latencies at the ipsilateral Erb’s point compared to HC. This trend is substantiated by significantly longer N9 latencies in CLBP patients compared to normative data. None of the other parameters showed any significant difference between CLBP patients and HC. Overall, our data indicate small differences of the peripheral N9 SEP component; however, these differences cannot explain the reflex delay observed in CLBP patients. While it was important to rule out the contribution of early somatosensory processing and to elucidate its contribution to the delayed reflex responses in CLBP patients, further research is needed to find the primary source(s) of time-delayed reflexes in CLBP. PMID:27799904

  10. Voxel-based morphometry in opera singers: Increased gray-matter volume in right somatosensory and auditory cortices.

    PubMed

    Kleber, Boris; Veit, Ralf; Moll, Christina Valérie; Gaser, Christian; Birbaumer, Niels; Lotze, Martin

    2016-06-01

    In contrast to instrumental musicians, professional singers do not train on a specific instrument but perfect a motor system that has already been extensively trained during speech motor development. Previous functional imaging studies suggest that experience with singing is associated with enhanced somatosensory-based vocal motor control. However, experience-dependent structural plasticity in vocal musicians has rarely been studied. We investigated voxel-based morphometry (VBM) in 27 professional classical singers and compared gray matter volume in regions of the "singing-network" to an age-matched group of 28 healthy volunteers with no special singing experience. We found right hemispheric volume increases in professional singers in ventral primary somatosensory cortex (larynx S1) and adjacent rostral supramarginal gyrus (BA40), as well as in secondary somatosensory (S2) and primary auditory cortices (A1). Moreover, we found that earlier commencement with vocal training correlated with increased gray-matter volume in S1. However, in contrast to studies with instrumental musicians, this correlation only emerged in singers who began their formal training after the age of 14years, when speech motor development has reached its first plateau. Structural data thus confirm and extend previous functional reports suggesting a pivotal role of somatosensation in vocal motor control with increased experience in singing. Results furthermore indicate a sensitive period for developing additional vocal skills after speech motor coordination has matured.

  11. The Tactile Window to Consciousness is Characterized by Frequency-Specific Integration and Segregation of the Primary Somatosensory Cortex

    PubMed Central

    Frey, Julia Natascha; Ruhnau, Philipp; Leske, Sabine; Siegel, Markus; Braun, Christoph; Weisz, Nathan

    2016-01-01

    We recently proposed that besides levels of local cortical excitability, also distinct pre-stimulus network states (windows to consciousness) determine whether a near-threshold stimulus will be consciously perceived. In the present magnetoencephalography study, we scrutinised these pre-stimulus network states with a focus on the primary somatosensory cortex. For this purpose participants performed a simple near-threshold tactile detection task. Confirming previous studies, we found reduced alpha and beta power in the somatosensory region contralateral to stimulation prior to correct stimulus detection as compared to undetected stimuli, and stronger event-related responses following successful stimulus detection. As expected, using graph theoretical measures, we also observed modulated pre-stimulus network level integration. Specifically, the right primary somatosensory cortex contralateral to stimulation showed an increased integration in the theta band, and additionally, a decreased integration in the beta band. Overall, these results underline the importance of network states for enabling conscious perception. Moreover, they indicate that also a reduction of irrelevant functional connections contributes to the window to consciousness by tuning pre-stimulus pathways of information flow. PMID:26864304

  12. Somatosensory feedback modulates the respiratory motor program of crystallized birdsong

    PubMed Central

    Suthers, Roderick A.; Goller, Franz; Wild, J. Martin

    2002-01-01

    Birdsong, like human speech, involves rapid, repetitive, or episodic motor patterns requiring precise coordination between respiratory, vocal organ, and vocal tract muscles. The song units or syllables of most adult songbirds exhibit a high degree of acoustic stereotypy that persists for days or months after the elimination of auditory feedback by deafening. Adult song is assumed to depend on central motor programs operating independently from immediate sensory feedback. Nothing is known, however, about the possible role of mechanoreceptive or other somatosensory feedback in the motor control of birdsong. Even in the case of human speech, the question of “how and when sensory information is used in normal speaking conditions… remains unanswered” and controversial [Smith, A. (1992) Crit. Rev. Oral Biol. Med. 3, 233–267]. We report here evidence for somatosensory modulation of ongoing song motor patterns. These patterns include the respiratory muscles that, in both birdsong and speech, provide the power for vocalization. Perturbing respiratory pressure by a brief, irregularly timed injection of air into the cranial thoracic air sac during song elicited a compensatory reduction in the electrical activity of the abdominal expiratory muscles, both in hearing and deafened adult northern cardinals (Cardinalis cardinalis). This muscle response was absent or reduced during quiet respiration, suggesting it is specifically linked to phonation. Our findings indicate that somatosensory feedback to expiratory muscles elicits compensatory adjustments that help stabilize, in real time, the subsyringeal pressure against fluctuations caused by changes in posture or physical activity. PMID:11943843

  13. Representation of tactile curvature in macaque somatosensory area 2

    PubMed Central

    Connor, Charles E.; Hsiao, Steven S.

    2013-01-01

    Tactile shape information is elaborated in a cortical hierarchy spanning primary (SI) and secondary somatosensory cortex (SII). Indeed, SI neurons in areas 3b and 1 encode simple contour features such as small oriented bars and edges, whereas higher order SII neurons represent large curved contour features such as angles and arcs. However, neural coding of these contour features has not been systematically characterized in area 2, the most caudal SI subdivision in the postcentral gyrus. In the present study, we analyzed area 2 neural responses to embossed oriented bars and curved contour fragments to establish whether curvature representations are generated in the postcentral gyrus. We found that many area 2 neurons (26 of 112) exhibit clear curvature tuning, preferring contours pointing in a particular direction. Fewer area 2 neurons (15 of 112) show preferences for oriented bars. Because area 2 response patterns closely resembled SII patterns, we also compared area 2 and SII response time courses to characterize the temporal dynamics of curvature synthesis in the somatosensory system. We found that curvature representations develop and peak concurrently in area 2 and SII. These results reveal that transitions from orientation tuning to curvature selectivity in the somatosensory cortical hierarchy occur within SI rather than between SI and SII. PMID:23536717

  14. Four-dimensional maps of the human somatosensory system

    PubMed Central

    Avanzini, Pietro; Abdollahi, Rouhollah O.; Sartori, Ivana; Caruana, Fausto; Pelliccia, Veronica; Casaceli, Giuseppe; Mai, Roberto; Lo Russo, Giorgio; Rizzolatti, Giacomo; Orban, Guy A.

    2016-01-01

    A fine-grained description of the spatiotemporal dynamics of human brain activity is a major goal of neuroscientific research. Limitations in spatial and temporal resolution of available noninvasive recording and imaging techniques have hindered so far the acquisition of precise, comprehensive four-dimensional maps of human neural activity. The present study combines anatomical and functional data from intracerebral recordings of nearly 100 patients, to generate highly resolved four-dimensional maps of human cortical processing of nonpainful somatosensory stimuli. These maps indicate that the human somatosensory system devoted to the hand encompasses a widespread network covering more than 10% of the cortical surface of both hemispheres. This network includes phasic components, centered on primary somatosensory cortex and neighboring motor, premotor, and inferior parietal regions, and tonic components, centered on opercular and insular areas, and involving human parietal rostroventral area and ventral medial-superior-temporal area. The technique described opens new avenues for investigating the neural basis of all levels of cortical processing in humans. PMID:26976579

  15. Four-dimensional maps of the human somatosensory system.

    PubMed

    Avanzini, Pietro; Abdollahi, Rouhollah O; Sartori, Ivana; Caruana, Fausto; Pelliccia, Veronica; Casaceli, Giuseppe; Mai, Roberto; Lo Russo, Giorgio; Rizzolatti, Giacomo; Orban, Guy A

    2016-03-29

    A fine-grained description of the spatiotemporal dynamics of human brain activity is a major goal of neuroscientific research. Limitations in spatial and temporal resolution of available noninvasive recording and imaging techniques have hindered so far the acquisition of precise, comprehensive four-dimensional maps of human neural activity. The present study combines anatomical and functional data from intracerebral recordings of nearly 100 patients, to generate highly resolved four-dimensional maps of human cortical processing of nonpainful somatosensory stimuli. These maps indicate that the human somatosensory system devoted to the hand encompasses a widespread network covering more than 10% of the cortical surface of both hemispheres. This network includes phasic components, centered on primary somatosensory cortex and neighboring motor, premotor, and inferior parietal regions, and tonic components, centered on opercular and insular areas, and involving human parietal rostroventral area and ventral medial-superior-temporal area. The technique described opens new avenues for investigating the neural basis of all levels of cortical processing in humans. PMID:26976579

  16. Effects of intrathecal anandamide on somatosensory evoked responses in rats.

    PubMed

    Bir, Levent Sinan; Ercan, Sevim

    2006-02-01

    Anandamide, endogenous ligand of cannabinoid receptors produces similar effects of cannabinoids via CB1 receptors in the central nervous system. Its effect on ascending pathways of somatosensory conduction and somatosensory cortex is not known. The aim of this study was to determine the effects of anandamide on somatosensory evoked potentials (SEP). In this study, 24 Wistar male rats were used. The rats were divided into 4 groups. At the beginning, sciatic nerve stimulated scalp SEP traces were obtained from all of the rats. Later, 0.02 cm(3) anhydrous ethanol, 100 microg/kg, 200 microg/kg and 400 microg/kg anandamide dissolved in anhydrous ethanol were injected intrathecally to the first (control), second, third and fourth groups, respectively. Five minutes later, second SEP traces were started. In every SEP trace, two negative waves (N1, N2) following positive deflections were obtained. The latency and amplitudes of these waves assessed were compared in each group. In control and second groups, the parameters of these waves before and after the injections were not significantly different. However, in the third and fourth groups, latencies of N1 and N2 after injections were found significantly longer. This effect was dose dependent. In any of the groups, no significant changes were detected in the amplitudes after injections. In conclusion, anandamide, when injected intrathecally in pharmacological doses caused an induction of moderate conduction delay in SEP systems. PMID:16289169

  17. Representation of tactile curvature in macaque somatosensory area 2.

    PubMed

    Yau, Jeffrey M; Connor, Charles E; Hsiao, Steven S

    2013-06-01

    Tactile shape information is elaborated in a cortical hierarchy spanning primary (SI) and secondary somatosensory cortex (SII). Indeed, SI neurons in areas 3b and 1 encode simple contour features such as small oriented bars and edges, whereas higher order SII neurons represent large curved contour features such as angles and arcs. However, neural coding of these contour features has not been systematically characterized in area 2, the most caudal SI subdivision in the postcentral gyrus. In the present study, we analyzed area 2 neural responses to embossed oriented bars and curved contour fragments to establish whether curvature representations are generated in the postcentral gyrus. We found that many area 2 neurons (26 of 112) exhibit clear curvature tuning, preferring contours pointing in a particular direction. Fewer area 2 neurons (15 of 112) show preferences for oriented bars. Because area 2 response patterns closely resembled SII patterns, we also compared area 2 and SII response time courses to characterize the temporal dynamics of curvature synthesis in the somatosensory system. We found that curvature representations develop and peak concurrently in area 2 and SII. These results reveal that transitions from orientation tuning to curvature selectivity in the somatosensory cortical hierarchy occur within SI rather than between SI and SII.

  18. A case of thalamic syndrome: somatosensory influences on visual orientation

    PubMed Central

    Anastasopoulos, D; Bronstein, A

    1999-01-01

    The ability to set a straight line to the perceived gravitational vertical (subjective visual vertical, SVV) was investigated in a 21 year old woman with long standing left hemihypaesthesia due to a posterior thalamic infarct. The putative structures involved were the somatosensory and vestibular thalamus (VPL, VPM) and associative (pulvinar) thalamus. The SVV was normal when seated upright. When lying on her right side, line settings deviated about 17° to the right, which is the normal A-effect. When lying on the hypaesthetic side the mean SVV remained close to true vertical—that is, the A-effect was absent, and there was a large increase in variability of the SVV settings. The findings support the view that the body tilt-induced bias of the SVV (A-effect) is largely mediated by somatosensory afferents. The finding that the A-effect was absent only when lying on the hypaesthetic side suggests that, during body tilt, the somatosensory system participates in visuogravitational orientation.

 PMID:10449566

  19. Multilevel somatosensory system disinhibition in children with migraine.

    PubMed

    Valeriani, Massimiliano; Rinalduzzi, Steno; Vigevano, Federico

    2005-11-01

    Although migraine is characterised by an abnormal cortical excitability level, whether the central nervous system is hyper- or hypo-excitable in migraine still remains an unsolved problem. The aim of our study was to compare the somatosensory evoked potential (SEP) recovery cycle, a marker of the somatosensory system's excitability, in a group of 15 children suffering from migraine without aura (MO) (mean age 11.7+/-1.6 years, five males, 10 females) and 10 control age-matched subjects (CS) (mean age 10.9+/-2.1 years, six males, four females). We calculated the SEP's latency and amplitude modifications after paired electrical stimuli at 5, 20 and 40 ms interstimulus intervals (ISIs), comparing it with a single stimulus condition assumed as the baseline. In MO patients, the amplitudes of the cervical N13 and of the cortical N20, P24 and N30 responses at 20 and 40 ms ISIs showed a higher recovery than in CS (two-way ANOVA, P<0.05). Since, the SEP recovery cycle depends on the inhibitory interneuron function, our findings suggest that a somatosensory system disinhibition takes place in migraine. This is a generalized phenomenon, not limited to the cerebral cortex, but concerning also the cervical grey matter. The SEP recovery cycle reflects the intracellular concentration of Na(+), therefore, the shortened recovery cycle in our MO patients suggests a high level of intracellular Na(+) and a consequent depolarized resting membrane potential, possibly due to an impaired Na(+) -K(+) ATPase function in migraine. PMID:16213092

  20. Activity of Somatosensory-Responsive Neurons in High Subdivisions of SI Cortex during Locomotion

    PubMed Central

    Favorov, Oleg V.; Nilaweera, Wijitha U.; Miasnikov, Alexandre A.

    2015-01-01

    Responses of neurons in the primary somatosensory cortex during movements are poorly understood, even during such simple tasks as walking on a flat surface. In this study, we analyzed spike discharges of neurons in the rostral bank of the ansate sulcus (areas 1–2) in 2 cats while the cats walked on a flat surface or on a horizontal ladder, a complex task requiring accurate stepping. All neurons (n = 82) that had receptive fields (RFs) on the contralateral forelimb exhibited frequency modulation of their activity that was phase locked to the stride cycle during simple locomotion. Neurons with proximal RFs (upper arm/shoulder) and pyramidal tract-projecting neurons (PTNs) with fast-conducting axons tended to fire at peak rates in the middle of the swing phase, whereas neurons with RFs on the distal limb (wrist/paw) and slow-conducting PTNs typically showed peak firing at the transition between swing and stance phases. Eleven of 12 neurons with tactile RFs on the volar forepaw began firing toward the end of swing, with peak activity occurring at the moment of foot contact with floor, thereby preceding the evoked sensory volley from touch receptors. Requirement to step accurately on the ladder affected 91% of the neurons, suggesting their involvement in control of accuracy of stepping. During both tasks, neurons exhibited a wide variety of spike distributions within the stride cycle, suggesting that, during either simple or ladder locomotion, they represent the cycling somatosensory events in their activity both predictively before and reflectively after these events take place. PMID:25995465

  1. Somatosensory temporal discrimination threshold is increased in patients with cerebellar atrophy.

    PubMed

    Manganelli, Fiore; Dubbioso, Raffaele; Pisciotta, Chiara; Antenora, Antonella; Nolano, Maria; De Michele, Giuseppe; Filla, Alessandro; Berardelli, Alfredo; Santoro, Lucio

    2013-08-01

    Processing of time in the millisecond range seems to depend on cerebellar function and it can be assessed by using the somatosensory temporal discrimination threshold testing. No studies have yet investigated this temporal discrimination task in patients with cerebellar atrophy. Eleven patients with degenerative cerebellar ataxia and 11 controls underwent somatosensory temporal discrimination threshold evaluation. The degree of cerebellar dysfunction was measured by the International Cooperative Ataxia Rating Scale. Somatosensory temporal discrimination threshold was higher in patients compared to controls for each stimulated site (hand, neck, and eye). Age, disease duration, and International Cooperative Ataxia Rating Scale scores were not correlated to somatosensory temporal discrimination threshold. Somatosensory temporal discrimination threshold is abnormal in patients with cerebellar atrophy. These findings suggest that the cerebellum plays a role in modulating the somatosensory temporal discrimination threshold and confirm the role of cerebellum in the processing of time in the millisecond range.

  2. Spatiotemporal dynamics of bimanual integration in human somatosensory cortex and their relevance to bimanual object manipulation.

    PubMed

    Jung, Patrick; Klein, Johannes C; Wibral, Michael; Hoechstetter, Karsten; Bliem, Barbara; Lu, Ming-Kuei; Wahl, Mathias; Ziemann, Ulf

    2012-04-18

    Little is known about the spatiotemporal dynamics of cortical responses that integrate slightly asynchronous somatosensory inputs from both hands. This study aimed to clarify the timing and magnitude of interhemispheric interactions during early integration of bimanual somatosensory information in different somatosensory regions and their relevance for bimanual object manipulation and exploration. Using multi-fiber probabilistic diffusion tractography and MEG source analysis of conditioning-test (C-T) median nerve somatosensory evoked fields in healthy human subjects, we sought to extract measures of structural and effective callosal connectivity between different somatosensory cortical regions and correlated them with bimanual tactile task performance. Neuromagnetic responses were found in major somatosensory regions, i.e., primary somatosensory cortex SI, secondary somatosensory cortex SII, posterior parietal cortex, and premotor cortex. Contralateral to the test stimulus, SII activity was maximally suppressed by 51% at C-T intervals of 40 and 60 ms. This interhemispheric inhibition of the contralateral SII source activity correlated directly and topographically specifically with the fractional anisotropy of callosal fibers interconnecting SII. Thus, the putative pathway that mediated inhibitory interhemispheric interactions in SII was a transcallosal route from ipsilateral to contralateral SII. Moreover, interhemispheric inhibition of SII source activity correlated directly with bimanual tactile task performance. These findings were exclusive to SII. Our data suggest that early interhemispheric somatosensory integration primarily occurs in SII, is mediated by callosal fibers that interconnect homologous SII areas, and has behavioral importance for bimanual object manipulation and exploration.

  3. Choice of contact points during multidigit grasping: effect of predictability of object center of mass location.

    PubMed

    Lukos, Jamie; Ansuini, Caterina; Santello, Marco

    2007-04-01

    It has been shown that when subjects can predict object properties [e.g., weight or center of mass (CM)], fingertip forces are appropriately scaled before the object is lifted, i.e., before somatosensory feedback can be processed. However, it is not known whether subjects, in addition to these anticipatory force mechanisms, exploit the ability to choose where digits can be placed to facilitate object manipulation. We addressed this question by asking subjects to reach and grasp an object whose CM was changed to the left, center, or right of the object in either a predictable or unpredictable manner. The only task requirement was to minimize object roll during lift. We hypothesized that subjects would modulate contact points but only when object CM location could be predicted. As expected, object roll was significantly smaller in the predictable condition. This experimental condition was also associated with statistically distinct spatial distributions of contact points as a function of object CM location but primarily when large torques had to be counteracted, i.e., for right and left CM locations. In contrast, when subjects could not anticipate CM location, a "default" distribution of contact points was used, this being statistically indistinguishable from that adopted for the center CM location in the predictable condition. We conclude that choice of contact points is integrated with anticipatory force control mechanisms to facilitate object manipulation. These results demonstrate that planning of digit placement is an important component of grasp control.

  4. Does somatosensory discrimination activate different brain areas in children with unilateral cerebral palsy compared to typically developing children? An fMRI study.

    PubMed

    Van de Winckel, Ann; Verheyden, Geert; Wenderoth, Nici; Peeters, Ron; Sunaert, Stefan; Van Hecke, Wim; De Cock, Paul; Desloovere, Kaat; Eyssen, Maria; Feys, Hilde

    2013-05-01

    Aside from motor impairment, many children with unilateral cerebral palsy (CP) experience altered tactile, proprioceptive, and kinesthetic awareness. Sensory deficits are addressed in rehabilitation programs, which include somatosensory discrimination exercises. In contrast to adult stroke patients, data on brain activation, occurring during somatosensory discrimination exercises, are lacking in CP children. Therefore, this study investigated brain activation with functional magnetic resonance imaging (fMRI) during passively guided somatosensory discrimination exercises in 18 typically developing children (TD) (age, M=14 ± 1.92 years; 11 girls) and 16 CP children (age, M=15 ± 2.54 years; 8 girls). The demographic variables between both groups were not statistically different. An fMRI compatible robot guided the right index finger and performed pairs of unfamiliar geometric shapes in the air, which were judged on their equality. The control condition comprised discrimination of music fragments. Both groups exhibited significant activation (FDR, p<.05) in frontoparietal, temporal, cerebellar areas, and insula, similar to studies in adults. The frontal areas encompassed ventral premotor areas, left postcentral gyrus, and precentral gyrus; additional supplementary motor area (SMA proper) activation in TD; as well as dorsal premotor, and parietal operculum recruitment in CP. On uncorrected level, p<.001, TD children revealed more left frontal lobe, and right cerebellum activation, compared to CP children. Conversely, CP children activated the left dorsal cingulate gyrus to a greater extent than TD children. These data provide incentives to investigate the effect of somatosensory discrimination during rehabilitation in CP, on clinical outcome and brain plasticity.

  5. Sensorimotor and cognitive involvement of the beta-gamma oscillation in the frontal N30 component of somatosensory evoked potentials.

    PubMed

    Cebolla, A M; Cheron, G

    2015-12-01

    The most consistent negative cortical component of somatosensory evoked potentials (SEPs), namely the frontal N30, can be considered more multidimensional than a strict item of standard somatosensory investigation, dedicated to tracking the afferent volley from the peripheral sensory nerve potentials to the primary somatosensory cortex. In this review, we revisited its classical sensorimotor implication within the framework of the recent oscillatory model of ongoing electroencephalogram (EEG) rhythms. Recently, the N30 component was demonstrated to be related to an increase in the power of beta-gamma EEG oscillation and a phase reorganization of the ongoing EEG oscillations (phase locking) in this frequency band. Thanks to high density EEG recordings and the inverse modeling method (swLORETA), it was shown that different overlapping areas of the motor and premotor cortex are specifically involved in generating the N30 in the form of a beta gamma oscillatory phase locking and power increase. This oscillatory approach has allowed a re-investigation of the movement gating behavior of the N30. It was demonstrated that the concomitant execution of finger movements by a stimulated hand impinges the temporal concentration of the ongoing beta/gamma EEG oscillations and abolished the N30 component. It was hypothesized that the involvement of neuronal populations in both the sensorimotor cortex and other related areas were unable to respond to the phasic sensory activation so could not phase-lock their oscillatory signals to the external sensory input during the movement. In this case, the actual movement has primacy over the artificial somatosensory input. The contribution of the ongoing oscillatory activity in the N30 emergence calls for a reappraisal of fundamental and clinical interpretations of the frontal N30 component. An absent or reduced amplitude of the N30 can now be viewed not only as a deficit in the activation of the somatosensory synaptic network in response

  6. Sensorimotor and cognitive involvement of the beta-gamma oscillation in the frontal N30 component of somatosensory evoked potentials.

    PubMed

    Cebolla, A M; Cheron, G

    2015-12-01

    The most consistent negative cortical component of somatosensory evoked potentials (SEPs), namely the frontal N30, can be considered more multidimensional than a strict item of standard somatosensory investigation, dedicated to tracking the afferent volley from the peripheral sensory nerve potentials to the primary somatosensory cortex. In this review, we revisited its classical sensorimotor implication within the framework of the recent oscillatory model of ongoing electroencephalogram (EEG) rhythms. Recently, the N30 component was demonstrated to be related to an increase in the power of beta-gamma EEG oscillation and a phase reorganization of the ongoing EEG oscillations (phase locking) in this frequency band. Thanks to high density EEG recordings and the inverse modeling method (swLORETA), it was shown that different overlapping areas of the motor and premotor cortex are specifically involved in generating the N30 in the form of a beta gamma oscillatory phase locking and power increase. This oscillatory approach has allowed a re-investigation of the movement gating behavior of the N30. It was demonstrated that the concomitant execution of finger movements by a stimulated hand impinges the temporal concentration of the ongoing beta/gamma EEG oscillations and abolished the N30 component. It was hypothesized that the involvement of neuronal populations in both the sensorimotor cortex and other related areas were unable to respond to the phasic sensory activation so could not phase-lock their oscillatory signals to the external sensory input during the movement. In this case, the actual movement has primacy over the artificial somatosensory input. The contribution of the ongoing oscillatory activity in the N30 emergence calls for a reappraisal of fundamental and clinical interpretations of the frontal N30 component. An absent or reduced amplitude of the N30 can now be viewed not only as a deficit in the activation of the somatosensory synaptic network in response

  7. Military veterans with mental health problems: a protocol for a systematic review to identify whether they have an additional risk of contact with criminal justice systems compared with other veterans groups

    PubMed Central

    2012-01-01

    Background There is concern that some veterans of armed forces, in particular those with mental health, drug or alcohol problems, experience difficulty returning to a civilian way of life and may subsequently come into contact with criminal justice services and imprisonment. The aim of this review is to examine whether military veterans with mental health problems, including substance use, have an additional risk of contact with criminal justice systems when compared with veterans who do not have such problems. The review will also seek to identify veterans’ views and experiences on their contact with criminal justice services, what contributed to or influenced their contact and whether there are any differences, including international and temporal, in incidence, contact type, veteran type, their presenting health needs and reported experiences. Methods/design In this review we will adopt a methodological model similar to that previously used by other researchers when reviewing intervention studies. The model, which we will use as a framework for conducting a review of observational and qualitative studies, consists of two parallel synthesis stages within the review process; one for quantitative research and the other for qualitative research. The third stage involves a cross study synthesis, enabling a deeper understanding of the results of the quantitative synthesis. A range of electronic databases, including MEDLINE, PsychINFO, CINAHL, will be systematically searched, from 1939 to present day, using a broad range of search terms that cover four key concepts: mental health, military veterans, substance misuse, and criminal justice. Studies will be screened against topic specific inclusion/exclusion criteria and then against a smaller subset of design specific inclusion/exclusion criteria. Data will be extracted for those studies that meet the inclusion criteria, and all eligible studies will be critically appraised. Included studies, both quantitative and

  8. The Role of Attention in Somatosensory Processing: A Multi-trait, Multi-method Analysis.

    PubMed

    Wodka, Ericka L; Puts, Nicolaas A J; Mahone, E Mark; Edden, Richard A E; Tommerdahl, Mark; Mostofsky, Stewart H

    2016-10-01

    Sensory processing abnormalities in autism have largely been described by parent report. This study used a multi-method (parent-report and measurement), multi-trait (tactile sensitivity and attention) design to evaluate somatosensory processing in ASD. Results showed multiple significant within-method (e.g., parent report of different traits)/cross-trait (e.g., attention and tactile sensitivity) correlations, suggesting that parent-reported tactile sensory dysfunction and performance-based tactile sensitivity describe different behavioral phenomena. Additionally, both parent-reported tactile functioning and performance-based tactile sensitivity measures were significantly associated with measures of attention. Findings suggest that sensory (tactile) processing abnormalities in ASD are multifaceted, and may partially reflect a more global deficit in behavioral regulation (including attention). Challenges of relying solely on parent-report to describe sensory difficulties faced by children/families with ASD are also highlighted.

  9. The Role of Attention in Somatosensory Processing: A Multi-trait, Multi-method Analysis

    PubMed Central

    Puts, Nicolaas A. J.; Mahone, E. Mark; Edden, Richard A. E.; Tommerdahl, Mark; Mostofsky, Stewart H.

    2016-01-01

    Sensory processing abnormalities in autism have largely been described by parent report. This study used a multi-method (parent-report and measurement), multi-trait (tactile sensitivity and attention) design to evaluate somatosensory processing in ASD. Results showed multiple significant within-method (e.g., parent report of different traits)/cross-trait (e.g., attention and tactile sensitivity) correlations, suggesting that parent-reported tactile sensory dysfunction and performance-based tactile sensitivity describe different behavioral phenomena. Additionally, both parent-reported tactile functioning and performance-based tactile sensitivity measures were significantly associated with measures of attention. Findings suggest that sensory (tactile) processing abnormalities in ASD are multifaceted, and may partially reflect a more global deficit in behavioral regulation (including attention). Challenges of relying solely on parent-report to describe sensory difficulties faced by children/families with ASD are also highlighted. PMID:27448580

  10. The Role of Attention in Somatosensory Processing: A Multi-trait, Multi-method Analysis.

    PubMed

    Wodka, Ericka L; Puts, Nicolaas A J; Mahone, E Mark; Edden, Richard A E; Tommerdahl, Mark; Mostofsky, Stewart H

    2016-10-01

    Sensory processing abnormalities in autism have largely been described by parent report. This study used a multi-method (parent-report and measurement), multi-trait (tactile sensitivity and attention) design to evaluate somatosensory processing in ASD. Results showed multiple significant within-method (e.g., parent report of different traits)/cross-trait (e.g., attention and tactile sensitivity) correlations, suggesting that parent-reported tactile sensory dysfunction and performance-based tactile sensitivity describe different behavioral phenomena. Additionally, both parent-reported tactile functioning and performance-based tactile sensitivity measures were significantly associated with measures of attention. Findings suggest that sensory (tactile) processing abnormalities in ASD are multifaceted, and may partially reflect a more global deficit in behavioral regulation (including attention). Challenges of relying solely on parent-report to describe sensory difficulties faced by children/families with ASD are also highlighted. PMID:27448580

  11. Adaptation to Coriolis force perturbation of movement trajectory; role of proprioceptive and cutaneous somatosensory feedback.

    PubMed

    Lackner, James R; DiZio, Paul

    2002-01-01

    Subjects exposed to constant velocity rotation in a large fully-enclosed room that rotates initially make large reaching errors in pointing to targets. The paths and endpoints of their reaches are deviated in the direction of the transient lateral Coriolis forces generated by the forward velocity of their reaches. With additional reaches, subjects soon reach in straighter paths and become more accurate at landing on target even in the absence of visual feedback about their movements. Two factors contribute to this adaptation: first, muscle spindle and golgi tendon organ feedback interpreted in relation to efferent commands provide information about movement trajectory, and second, somatosensory stimulation of the fingertip at the completion of a reach provides information about the location of the fingertip relative to the torso.

  12. Adaptation to Coriolis force perturbation of movement trajectory; role of proprioceptive and cutaneous somatosensory feedback

    NASA Technical Reports Server (NTRS)

    Lackner, James R.; DiZio, Paul

    2002-01-01

    Subjects exposed to constant velocity rotation in a large fully-enclosed room that rotates initially make large reaching errors in pointing to targets. The paths and endpoints of their reaches are deviated in the direction of the transient lateral Coriolis forces generated by the forward velocity of their reaches. With additional reaches, subjects soon reach in straighter paths and become more accurate at landing on target even in the absence of visual feedback about their movements. Two factors contribute to this adaptation: first, muscle spindle and golgi tendon organ feedback interpreted in relation to efferent commands provide information about movement trajectory, and second, somatosensory stimulation of the fingertip at the completion of a reach provides information about the location of the fingertip relative to the torso.

  13. Population analysis of single neurons in cat somatosensory cortex.

    PubMed

    Warren, R A; Dykes, R W

    1992-01-01

    Single neurons in the somatosensory cortex are divisible into a population with receptive fields and a population without receptive fields. These two populations display different laminar distributions, and their respective functions are unknown. We compared other physiological characteristics of these two neuronal populations in an attempt to understand why some neurons lack a receptive field. Only 23% of 465 neurons isolated in the somatosensory cortex of halothane-anesthetized cats displayed a cutaneous receptive field. The iontophoretic administration of glutamate uncovered input from the periphery in another 34% of the sample, leaving 43% of the neurons without evidence of peripheral input under these experimental conditions. Neurons with a receptive field were spontaneously active much more often than neurons lacking peripheral inputs, and their rates of discharge were higher. No differences were found between neurons having a receptive field uncovered with glutamate and those unaffected by glutamate. In all classes of neurons, those cells with spontaneous activity were excited by smaller amounts of glutamate than were silent neurons, but sensitivity to glutamate was not correlated with the presence or absence of a receptive field. We infer that some classes of somatosensory cortical neurons receive strong thalamocortical inputs, whereas others have only relatively weak or no thalamocortical connections. In other experiments we have shown also that those neurons lacking a receptive field and/or spontaneous activity were more likely to be plastic than those with stronger inputs (see Warren and Dykes, 1993a,b), suggesting that neurons having weaker afferent inputs can be more readily modified under certain circumstances. PMID:1362827

  14. Prism adaptation contrasts perceptual habituation for repetitive somatosensory stimuli.

    PubMed

    Torta, D M; Tatu, M K; Cotroneo, D; Alamia, A; Folegatti, A; Trojan, J

    2016-03-01

    Prism adaptation (PA) is a non-invasive procedure that requires performing a visuo-motor pointing task while wearing prism goggles inducing a visual displacement of the pointed target. This procedure involves a reorganization of sensorimotor coordination, and induces long-lasting effects on numerous higher-order cognitive functions in healthy volunteers and neglect patients. Prismatic displacement (PD) of the visual field can be induced when prisms are worn but no sensorimotor task is required. In this case, it is unlikely that any subsequent reorganization takes place. The effects of PD are short-lived in the sense that they last as long as prisms are worn. In this study we aimed, to the best of our knowledge for the first time, at investigating whether PA and PD induce changes in the perception of intensity of nociceptive and non- nociceptive somatosensory stimuli. We induced, in healthy volunteers, PD (experiment 1), or PA (experiment 2) and asked participants to rate the intensity of the stimuli applied to the hand undergoing the visuo-proprioceptive conflict (experiment 1) or adaptation (experiment 2). Our results indicate that: 1) the visuo-proprioceptive conflict induced by PD does not reduce the perceived intensity of the stimuli, 2) PA prevents perceptual habituation for both nociceptive and non-nociceptive somatosensory stimuli. Moreover, to investigate the possible underlying mechanisms of the effects of PA we conducted a third experiment in which stimuli were applied both at the adapted and the non-adapted hand. In line with the results of experiment 2, we found that perceptual habituation was prevented for stimuli applied onto the adapted hand. Moreover, we observed the same finding for stimuli applied onto the non-adapted hand. This result suggests that the detention of habituation is not merely driven by changes in spatial attention allocation. Taken together, these data indicate that prisms can affect the perceived intensity of somatosensory stimuli

  15. Dissociating vestibular and somatosensory contributions to spatial orientation.

    PubMed

    Alberts, Bart B G T; Selen, Luc P J; Bertolini, Giovanni; Straumann, Dominik; Medendorp, W Pieter; Tarnutzer, Alexander A

    2016-07-01

    Inferring object orientation in the surroundings heavily depends on our internal sense of direction of gravity. Previous research showed that this sense is based on the integration of multiple information sources, including visual, vestibular (otolithic), and somatosensory signals. The individual noise characteristics and contributions of these sensors can be studied using spatial orientation tasks, such as the subjective visual vertical (SVV) task. A recent study reported that patients with complete bilateral vestibular loss perform similar as healthy controls on these tasks, from which it was conjectured that the noise levels of both otoliths and body somatosensors are roll-tilt dependent. Here, we tested this hypothesis in 10 healthy human subjects by roll tilting the head relative to the body to dissociate tilt-angle dependencies of otolith and somatosensory noise. Using a psychometric approach, we measured the perceived orientation, and its variability, of a briefly flashed line relative to the gravitational vertical (SVV). Measurements were taken at multiple body-in-space orientations (-90 to 90°, steps of 30°) and head-on-body roll tilts (30° left ear down, aligned, 30° right ear down). Results showed that verticality perception is processed in a head-in-space reference frame, with a systematic SVV error that increased with larger head-in-space orientations. Variability patterns indicated a larger contribution of the otolith organs around upright and a more substantial contribution of the body somatosensors at larger body-in-space roll tilts. Simulations show that these findings are consistent with a statistical model that involves tilt-dependent noise levels of both otolith and somatosensory signals, confirming dynamic shifts in the weights of sensory inputs with tilt angle. PMID:27075537

  16. Single-trial detection for intraoperative somatosensory evoked potentials monitoring.

    PubMed

    Hu, L; Zhang, Z G; Liu, H T; Luk, K D K; Hu, Y

    2015-12-01

    Abnormalities of somatosensory evoked potentials (SEPs) provide effective evidence for impairment of the somatosensory system, so that SEPs have been widely used in both clinical diagnosis and intraoperative neurophysiological monitoring. However, due to their low signal-to-noise ratio (SNR), SEPs are generally measured using ensemble averaging across hundreds of trials, thus unavoidably producing a tardiness of SEPs to the potential damages caused by surgical maneuvers and a loss of dynamical information of cortical processing related to somatosensory inputs. Here, we aimed to enhance the SNR of single-trial SEPs using Kalman filtering and time-frequency multiple linear regression (TF-MLR) and measure their single-trial parameters, both in the time domain and in the time-frequency domain. We first showed that, Kalman filtering and TF-MLR can effectively capture the single-trial SEP responses and provide accurate estimates of single-trial SEP parameters in the time domain and time-frequency domain, respectively. Furthermore, we identified significant correlations between the stimulus intensity and a set of indicative single-trial SEP parameters, including the correlation coefficient (between each single-trial SEPs and their average), P37 amplitude, N45 amplitude, P37-N45 amplitude, and phase value (at the zero-crossing points between P37 and N45). Finally, based on each indicative single-trial SEP parameter, we investigated the minimum number of trials required on a single-trial basis to suggest the existence of SEP responses, thus providing important information for fast SEP extraction in intraoperative monitoring. PMID:26557929

  17. Single-trial detection for intraoperative somatosensory evoked potentials monitoring.

    PubMed

    Hu, L; Zhang, Z G; Liu, H T; Luk, K D K; Hu, Y

    2015-12-01

    Abnormalities of somatosensory evoked potentials (SEPs) provide effective evidence for impairment of the somatosensory system, so that SEPs have been widely used in both clinical diagnosis and intraoperative neurophysiological monitoring. However, due to their low signal-to-noise ratio (SNR), SEPs are generally measured using ensemble averaging across hundreds of trials, thus unavoidably producing a tardiness of SEPs to the potential damages caused by surgical maneuvers and a loss of dynamical information of cortical processing related to somatosensory inputs. Here, we aimed to enhance the SNR of single-trial SEPs using Kalman filtering and time-frequency multiple linear regression (TF-MLR) and measure their single-trial parameters, both in the time domain and in the time-frequency domain. We first showed that, Kalman filtering and TF-MLR can effectively capture the single-trial SEP responses and provide accurate estimates of single-trial SEP parameters in the time domain and time-frequency domain, respectively. Furthermore, we identified significant correlations between the stimulus intensity and a set of indicative single-trial SEP parameters, including the correlation coefficient (between each single-trial SEPs and their average), P37 amplitude, N45 amplitude, P37-N45 amplitude, and phase value (at the zero-crossing points between P37 and N45). Finally, based on each indicative single-trial SEP parameter, we investigated the minimum number of trials required on a single-trial basis to suggest the existence of SEP responses, thus providing important information for fast SEP extraction in intraoperative monitoring.

  18. Multilevel Cortical Processing of Somatosensory Novelty: A Magnetoencephalography Study

    PubMed Central

    Naeije, Gilles; Vaulet, Thibaut; Wens, Vincent; Marty, Brice; Goldman, Serge; De Tiège, Xavier

    2016-01-01

    Using magnetoencephalography (MEG), this study investigates the spatio-temporal dynamics of the multilevel cortical processing of somatosensory change detection. Neuromagnetic signals of 16 healthy adult subjects (7 females and 9 males, mean age 29 ± 3 years) were recorded using whole-scalp-covering MEG while they underwent an oddball paradigm based on simple standard (right index fingertip tactile stimulation) and deviant (simultaneous right index fingertip and middle phalanx tactile stimulation) stimuli gathered into sequences to create and then deviate from stimulus patterns at multiple (local vs. global) levels of complexity. Five healthy adult subjects (3 females and 2 males, mean age 31, 6 ± 2 years) also underwent a similar oddball paradigm in which standard and deviant stimuli were flipped. Local deviations led to a somatosensory mismatch response peaking at 55–130 ms post-stimulus onset with a cortical generator located at the contralateral secondary somatosensory (cSII) cortex. The mismatch response was independent of the deviant stimuli physical characteristics. Global deviants led to a P300 response with cortical sources located bilaterally at temporo-parietal junction (TPJ) and supplementary motor area (SMA). The posterior parietal cortex (PPC) and the SMA were found to generate a contingent magnetic variation (CMV) attributed to top-down expectations. Amplitude of mismatch responses were modulated by top-down expectations and correlated with both the magnitude of the CMV and the P300 amplitude at the right TPJ. These results provide novel empirical evidence for a unified sensory novelty detection system in the human brain by linking detection of salient sensory stimuli in personal and extra-personal spaces to a common framework of multilevel cortical processing. PMID:27313523

  19. The modulation of somatosensory resonance by psychopathic traits and empathy

    PubMed Central

    Marcoux, Louis-Alexandre; Michon, Pierre-Emmanuel; Voisin, Julien I. A.; Lemelin, Sophie; Vachon-Presseau, Etienne; Jackson, Philip L.

    2013-01-01

    A large number of neuroimaging studies have shown neural overlaps between first-hand experiences of pain and the perception of pain in others. This shared neural representation of vicarious pain is thought to involve both affective and sensorimotor systems. A number of individual factors are thought to modulate the cerebral response to other's pain. The goal of this study was to investigate the impact of psychopathic traits on the relation between sensorimotor resonance to other's pain and self-reported empathy. Our group has previously shown that a steady-state response to non-painful stimulation is modulated by the observation of other people's bodily pain. This change in somatosensory response was interpreted as a form of somatosensory gating (SG). Here, using the same technique, SG was compared between two groups of 15 young adult males: one scoring very high on a self-reported measure of psychopathic traits [60.8 ± 4.98; Levenson's Self-Report Psychopathy Scale (LSRP)] and one scoring very low (42.7 ± 2.94). The results showed a significantly greater reduction of SG to pain observation for the high psychopathic traits group compared to the low psychopathic traits group. SG to pain observation was positively correlated with affective and interpersonal facet of psychopathy in the whole sample. The high psychopathic traits group also reported lower empathic concern (EC) scores than the low psychopathic traits group. Importantly, primary psychopathy, as assessed by the LSRP, mediated the relation between EC and SG to pain observation. Together, these results suggest that increase somatosensory resonance to other's pain is not exclusively explained by trait empathy and may be linked to other personality dimensions, such as psychopathic traits. PMID:23801950

  20. Robot-Assisted Proprioceptive Training with Added Vibro-Tactile Feedback Enhances Somatosensory and Motor Performance

    PubMed Central

    Cuppone, Anna Vera; Squeri, Valentina; Semprini, Marianna; Masia, Lorenzo; Konczak, Jürgen

    2016-01-01

    This study examined the trainability of the proprioceptive sense and explored the relationship between proprioception and motor learning. With vision blocked, human learners had to perform goal-directed wrist movements relying solely on proprioceptive/haptic cues to reach several haptically specified targets. One group received additional somatosensory movement error feedback in form of vibro-tactile cues applied to the skin of the forearm. We used a haptic robotic device for the wrist and implemented a 3-day training regimen that required learners to make spatially precise goal-directed wrist reaching movements without vision. We assessed whether training improved the acuity of the wrist joint position sense. In addition, we checked if sensory learning generalized to the motor domain and improved spatial precision of wrist tracking movements that were not trained. The main findings of the study are: First, proprioceptive acuity of the wrist joint position sense improved after training for the group that received the combined proprioceptive/haptic and vibro-tactile feedback (VTF). Second, training had no impact on the spatial accuracy of the untrained tracking task. However, learners who had received VTF significantly reduced their reliance on haptic guidance feedback when performing the untrained motor task. That is, concurrent VTF was highly salient movement feedback and obviated the need for haptic feedback. Third, VTF can be also provided by the limb not involved in the task. Learners who received VTF to the contralateral limb equally benefitted. In conclusion, somatosensory training can significantly enhance proprioceptive acuity within days when learning is coupled with vibro-tactile sensory cues that provide feedback about movement errors. The observable sensory improvements in proprioception facilitates motor learning and such learning may generalize to the sensorimotor control of the untrained motor tasks. The implications of these findings for

  1. Age-dependent changes in central somatosensory conduction time.

    PubMed

    Strenge, H; Hedderich, J

    1982-01-01

    Cervical and cortical somatosensory evoked potentials(SEPs) were recorded in 45 normal subjects. Absolute peak latencies and latency differences between the components P7, N9, N11, N13, P17 and N20 were measured. Subjects aged 40-60 years had significantly longer latencies of N13 and N20 than subjects aged 15-39 years. Moreover, statistical analysis revealed a significant prolongation of N9-N13, N11-N13 and N13-N20 transit times in older subjects. Possible connections with known morphological age-related findings are discussed. PMID:6288387

  2. Somatosensory temporal discrimination in essential tremor and isolated head and voice tremors.

    PubMed

    Conte, Antonella; Ferrazzano, Gina; Manzo, Nicoletta; Leodori, Giorgio; Fabbrini, Giovanni; Fasano, Alfonso; Tinazzi, Michele; Berardelli, Alfredo

    2015-05-01

    The aim of this study was to investigate the somatosensory temporal discrimination threshold in patients with essential tremor (sporadic and familial) and to evaluate whether somatosensory temporal discrimination threshold values differ depending on the body parts involved by tremor. We also investigated the somatosensory temporal discrimination in patients with isolated voice tremor. We enrolled 61 patients with tremor: 48 patients with essential tremor (31 patients with upper limb tremor alone, nine patients with head tremor alone, and eight patients with upper limb plus head tremor; 22 patients with familial vs. 26 sporadic essential tremor), 13 patients with isolated voice tremor, and 45 healthy subjects. Somatosensory temporal discrimination threshold values were normal in patients with familial essential tremor, whereas they were higher in patients with sporadic essential tremor. When we classified patients according to tremor distribution, somatosensory temporal discrimination threshold values were normal in patients with upper limb tremor and abnormal only in patients with isolated head tremor. Temporal discrimination threshold values were also abnormal in patients with isolated voice tremor. Somatosensory temporal discrimination processing is normal in patients with familial as well as in patients with sporadic essential tremor involving the upper limbs. By contrast, somatosensory temporal discrimination is altered in patients with isolated head tremor and voice tremor. This study with somatosensory temporal discrimination suggests that isolated head and voice tremors might possibly be considered as separate clinical entities from essential tremor.

  3. Somatosensory symptoms in unmedicated de novo patients with idiopathic Parkinson's disease.

    PubMed

    Schindlbeck, Katharina A; Mehl, Arne; Geffe, Sarah; Benik, Steffen; Tütüncü, Serdar; Klostermann, Fabian; Marzinzik, Frank

    2016-03-01

    Parkinson's disease (PD) is a neurodegenerative condition presenting with motor and non-motor symptoms including somatosensory disturbances. As neuropathic syndromes in advanced PD patients are supposed to be due to antiparkinsonian medication, we studied the presence of somatosensory symptoms and peripheral nerve function in drug naïve patients with PD as well as age-matched healthy controls. Somatosensory symptoms and signs were investigated in 39 de novo PD patients and 32 age-matched healthy controls using the modified Toronto Clinical Neuropathy Scale. To elucidate potential underlying mechanisms, peripheral nerve function was analyzed with sensory and motor neurography. About two thirds of de novo diagnosed levodopa naïve PD patients (66.7 %) reported somatosensory symptoms in comparison to one third of the control group (31.2 %) (p = 0.003). The presence of PD (p = 0.017) was a predictive factor for the occurrence of somatosensory symptoms among all participants. In contrast to the significantly higher frequency of somatosensory symptoms in patients with PD compared to controls, neurographically based peripheral nerve function did not differ between the groups. Our results indicate that somatosensory symptoms are a PD feature, which can be found when diagnosed first and independently of dopaminergic treatment. As the electrophysiologically determined peripheral nerve function was not different from that obtained in the control group, somatosensory symptoms are inherent in early PD and may be, at least partially, of central origin. PMID:26392189

  4. Somatosensory Profiles but Not Numbers of Somatosensory Abnormalities of Neuropathic Pain Patients Correspond with Neuropathic Pain Grading

    PubMed Central

    Konopka, Karl-Heinz; Harbers, Marten; Houghton, Andrea; Kortekaas, Rudie; van Vliet, Andre; Timmerman, Wia; den Boer, Johan A.; Struys, Michel M. R. F.; van Wijhe, Marten

    2012-01-01

    Due to the lack of a specific diagnostic tool for neuropathic pain, a grading system to categorize pain as ‘definite’, ‘probable’, ‘possible’ and ‘unlikely’ neuropathic was proposed. Somatosensory abnormalities are common in neuropathic pain and it has been suggested that a greater number of abnormalities would be present in patients with ‘probable’ and ‘definite’ grades. To test this hypothesis, we investigated the presence of somatosensory abnormalities by means of Quantitative Sensory Testing (QST) in patients with a clinical diagnosis of neuropathic pain and correlated the number of sensory abnormalities and sensory profiles to the different grades. Of patients who were clinically diagnosed with neuropathic pain, only 60% were graded as ‘definite’ or ‘probable’, while 40% were graded as ‘possible’ or ‘unlikely’ neuropathic pain. Apparently, there is a mismatch between a clinical neuropathic pain diagnosis and neuropathic pain grading. Contrary to the expectation, patients with ‘probable’ and ‘definite’ grades did not have a greater number of abnormalities. Instead, similar numbers of somatosensory abnormalities were identified for each grade. The profiles of sensory signs in ‘definite’ and ‘probable’ neuropathic pain were not significantly different, but different from the ‘unlikely’ grade. This latter difference could be attributed to differences in the prevalence of patients with a mixture of sensory gain and loss and with sensory loss only. The grading system allows a separation of neuropathic and non-neuropathic pain based on profiles but not on the total number of sensory abnormalities. Our findings indicate that patient selection based on grading of neuropathic pain may provide advantages in selecting homogenous groups for clinical research. PMID:22927981

  5. Long-term plasticity in adult somatosensory cortex: functional reorganization after surgical removal of an arteriovenous malformation.

    PubMed

    Burianová, Hana; Rich, Anina N; Williams, Mark; Morgan, Michael; Marstaller, Lars; Maruff, Paul; Baker, Chris I; Savage, Greg

    2015-01-01

    The temporal scale of neuroplasticity following acute alterations in brain structure due to neurosurgical intervention is still under debate. We conducted a longitudinal study with the objective of investigating the postoperative changes in a patient who underwent cerebrovascular surgery and who subsequently lost proprioception in the fingers of her right hand. The results show increased activation in contralesional somatosensory areas, additional recruitment of premotor and posterior parietal areas, and changes in functional connectivity with left postcentral gyrus. These findings demonstrate long-term modifications of cortical organization and as such have important implications for treatment strategies for patients with brain injury. PMID:25265167

  6. Origins of choice-related activity in mouse somatosensory cortex

    PubMed Central

    Yang, Hongdian; Kwon, Sung E.; Severson, Kyle S.; O’Connor, Daniel H.

    2015-01-01

    During perceptual decisions about faint or ambiguous sensory stimuli, even identical stimuli can produce different choices. Spike trains from sensory cortex neurons can predict trial-to-trial variability in choice. Choice-related spiking is widely studied to link cortical activity to perception, but its origins remain unclear. Using imaging and electrophysiology, we found that mouse primary somatosensory cortex neurons showed robust choice-related activity during a tactile detection task. Spike trains from primary mechanoreceptive neurons did not predict choices about identical stimuli. Spike trains from thalamic relay neurons showed highly transient, weak choice-related activity. Intracellular recordings in cortex revealed a prolonged choice-related depolarization in most neurons that was not accounted for by feedforward thalamic input. Top-down axons projecting from secondary to primary somatosensory cortex signaled choice. An intracellular measure of stimulus sensitivity determined which neurons converted choice-related depolarization into spiking. Our results reveal how choice-related spiking emerges across neural circuits and within single neurons. PMID:26642088

  7. Origins of choice-related activity in mouse somatosensory cortex.

    PubMed

    Yang, Hongdian; Kwon, Sung E; Severson, Kyle S; O'Connor, Daniel H

    2016-01-01

    During perceptual decisions about faint or ambiguous sensory stimuli, even identical stimuli can produce different choices. Spike trains from sensory cortex neurons can predict trial-to-trial variability in choice. Choice-related spiking is widely studied as a way to link cortical activity to perception, but its origins remain unclear. Using imaging and electrophysiology, we found that mouse primary somatosensory cortex neurons showed robust choice-related activity during a tactile detection task. Spike trains from primary mechanoreceptive neurons did not predict choices about identical stimuli. Spike trains from thalamic relay neurons showed highly transient, weak choice-related activity. Intracellular recordings in cortex revealed a prolonged choice-related depolarization in most neurons that was not accounted for by feed-forward thalamic input. Top-down axons projecting from secondary to primary somatosensory cortex signaled choice. An intracellular measure of stimulus sensitivity determined which neurons converted choice-related depolarization into spiking. Our results reveal how choice-related spiking emerges across neural circuits and within single neurons. PMID:26642088

  8. Alteration of somatosensory response in adulthood by early life stress.

    PubMed

    Takatsuru, Yusuke; Koibuchi, Noriyuki

    2015-01-01

    Early life stress is well-known as a critical risk factor for mental and cognitive disorders in adulthood. Such disorders are accompanied by altered neuro- (synapto-) genesis and gene expression. Because psychosomatic disorders induced by early life stress (e.g., physical and/or sexual abuse, and neglect) have become a socio-economic problem, it is very important to clarify the mechanisms underlying these changes. However, despite of intensive clinical and animal studies, such mechanisms have not yet been clarified. Although the disturbance of glucocorticoid and glutamate homeostasis by stress has been well-documented, it has not yet been clarified whether such disturbance by early life stress persists for life. Furthermore, since previous studies have focused on the detection of changes in specific brain regions, such as the hippocampus and prefrontal cortex, it has not been clarified whether early life stress induced changes in the sensory/motor system. Thus, in this review, we introduce recent studies on functional/structural changes in the somatosensory cortex induced by early life stress. We believe that this review provides new insights into the functional alteration of the somatosensory system induced by early life stress. Such information may have clinical relevance in terms of providing effective therapeutic interventions to early life stressed individuals. PMID:26041988

  9. Auditory-somatosensory integration and cortical plasticity in musical training.

    PubMed

    Pantev, Christo; Lappe, Claudia; Herholz, Sibylle C; Trainor, Laurel

    2009-07-01

    Learning to play a musical instrument requires complex multimodal skills involving simultaneous perception of several sensory modalities: auditory, visual, and somatosensory as well as the motor system. Musical training thus provides an adequate neuroscientific model to study multimodal integration and plasticity in musical training. The aim of this study was to investigate the impact of short-term uni- and multimodal musical training on auditory-somatosensory integration and plasticity. Two groups of nonmusicians were musically trained. The first group (sensorimotor-auditory group, SA) learned to play a musical sequence on the piano, whereas the second one (auditory group, A) actively listened to and made judgments about the correctness of the music. The training-induced cortical plasticity effect was assessed by recording musically elicited mismatch negativity (MMN) from magnetoencephalographic (MEG) measurements before and after training. The SA group showed significant enlargement of MMN after training compared to the A group, reflecting greater enhancement of musical representations in auditory cortex after sensorimotor-auditory training compared to mere auditory training. This study demonstrates that the sensorimotor and auditory systems integrate and that this multimodal training causes cortical reorganizational changes in the auditory cortex over and above the changes introduced by auditory training alone.

  10. Objective response detection in an electroencephalogram during somatosensory stimulation.

    PubMed

    Simpson, D M; Tierra-Criollo, C J; Leite, R T; Zayen, E J; Infantosi, A F

    2000-06-01

    Techniques for objective response detection aim to identify the presence of evoked potentials based purely on statistical principles. They have been shown to be potentially more sensitive than the conventional approach of subjective evaluation by experienced clinicians and could be of great clinical use. Three such techniques to detect changes in an electroencephalogram (EEG) synchronous with the stimuli, namely, magnitude-squared coherence (MSC), the phase-synchrony measure (PSM) and the spectral F test (SFT) were applied to EEG signals of 12 normal subjects under conventional somatosensory pulse stimulation to the tibial nerve. The SFT, which uses only the power spectrum, showed the poorest performance, while the PSM, based only on the phase spectrum, gave results almost as good as those of the MSC, which uses both phase and power spectra. With the latter two techniques, stimulus responses were evident in the frequency range of 20-80 Hz in all subjects after 200 stimuli (5 Hz stimulus frequency), whereas for visual recognition at least 500 stimuli are usually applied. Based on these results and on simulations, the phase-based techniques appear promising for the automated detection and monitoring of somatosensory evoked potentials.

  11. Somatosensory nuclei of the manatee brainstem and thalamus.

    PubMed

    Sarko, Diana K; Johnson, John I; Switzer, Robert C; Welker, Wally I; Reep, Roger L

    2007-09-01

    Florida manatees have an extensive, well-developed system of vibrissae distributed over their entire bodies and especially concentrated on the face. Although behavioral and anatomical assessments support the manatee's reliance on somatosensation, a systematic analysis of the manatee thalamus and brainstem areas dedicated to tactile input has never been completed. Using histochemical and histological techniques (including stains for myelin, Nissl, cytochrome oxidase, and acetylcholinesterase), we characterized the relative size, extent, and specializations of somatosensory regions of the brainstem and thalamus. The principal somatosensory regions of the brainstem (trigeminal, cuneate, gracile, and Bischoff's nucleus) and the thalamus (ventroposterior nucleus) were disproportionately large relative to nuclei dedicated to other sensory modalities, providing neuroanatomical evidence that supports the manatee's reliance on somatosensation. In fact, areas of the thalamus related to somatosensation (the ventroposterior and posterior nuclei) and audition (the medial geniculate nucleus) appeared to displace the lateral geniculate nucleus dedicated to the subordinate visual modality. Furthermore, it is noteworthy that, although the manatee cortex contains Rindenkerne (barrel-like cortical nuclei located in layer VI), no corresponding cell clusters were located in the brainstem ("barrelettes") or thalamus ("barreloids"). PMID:17722080

  12. Convergence of sensory inputs upon projection neurons of somatosensory cortex.

    PubMed

    Zarzecki, P; Wiggin, D M

    1982-01-01

    Cortico-cortical neurons and pyramidal tract neurons of the cat were tested for convergent inputs from forelimb afferents. Neurons were recorded in cortical areas 1, 2, and 3a. Consideration was given to both suprathreshold and subthreshold inputs evoked by electrical stimulation of forelimb nerves. Individual cortico-cortical neurons and also pyramidal tract neurons were characterized by convergence of multiple somatosensory inputs from different regions of skin, from several muscle groups, and between group I deep afferents and low threshold cutaneous afferents. Certain patterns of afferent input varied with cytoarchitectonic area. There was, however, no difference between area 3a and areas 1-2 in the incidence of cross-modality convergence in the form of input from cutaneous and also deep nerves. Many of the inputs were subthreshold. Arguments are presented that these inputs, though subthreshold, must be considered for a role in cortical information processing. The convergent nature of the sensory inputs is discussed in relation to the proposed specificities of cortical columns. The patterns of afferent inputs reaching cortico-cortical neurons seem to be appropriate for them to have a role in the formation of sensory fields of motor cortex neurons. PT neurons of somatosensory cortex have possible roles as modifiers of ascending sensory systems, however, the convergent input which these PT neurons receive argues against a simple relationship between the modality of peripheral stimuli influencing them and the modality of the ascending tract neurons under their descending control. PMID:7140889

  13. Induction of transcription factors in somatosensory cortex after tactile stimulation.

    PubMed

    Mack, K J; Mack, P A

    1992-01-01

    Immediate early response genes have been shown to be inducible in the central nervous system after a variety of stimuli. Induction of these transcription factors in cerebral cortex by a physiological stimulus had not previously been demonstrated. In this study, tactile stimuli induced multiple transcription factors in the somatosensory cortex. Adult male rats were lightly anesthetized with urethane. Tactile stimuli was delivered by a paint brush gently stroking an animals whiskers on one side of its face for a 15 min period. Two h later, the animals were sacrificed. Cortex contralateral to the stimulation was compared with ipsilateral cortex using antibodies raised against immediate early response gene products NGFI-A, NGFI-B, and c-fos. The different transcription factors showed slightly different patterns of response to the tactile stimulus. However, the induction of immunohistochemical staining was most prominent in layer 4 with all antibodies under study. This increase in the number of cell bodies stained was less robust than that seen in the somatosensory cortex after a seizure, and showed more of a predominance in layer 4 cells. These data demonstrate that physiologic stimulation can induce immediate early response genes in cortical cells, and that multiple immediate early response genes react to a stimulus. PMID:1312199

  14. Focal dystonia in musicians: linking motor symptoms to somatosensory dysfunction.

    PubMed

    Konczak, Jürgen; Abbruzzese, Giovanni

    2013-01-01

    Musician's dystonia (MD) is a neurological motor disorder characterized by involuntary contractions of those muscles involved in the play of a musical instrument. It is task-specific and initially only impairs the voluntary control of highly practiced musical motor skills. MD can lead to a severe decrement in a musician's ability to perform. While the etiology and the neurological pathomechanism of the disease remain unknown, it is known that MD like others forms of focal dystonia is associated with somatosensory deficits, specifically a decreased precision of tactile and proprioceptive perception. The sensory component of the disease becomes also evident by the patients' use of "sensory tricks" such as touching dystonic muscles to alleviate motor symptoms. The central premise of this paper is that the motor symptoms of MD have a somatosensory origin and are not fully explained as a problem of motor execution. We outline how altered proprioceptive feedback ultimately leads to a loss of voluntary motor control and propose two scenarios that explain why sensory tricks are effective. They are effective, because the sensorimotor system either recruits neural resources normally involved in tactile-proprioceptive (sensory) integration, or utilizes a fully functioning motor efference copy mechanism to align experienced with expected sensory feedback. We argue that an enhanced understanding of how a primary sensory deficit interacts with mechanisms of sensorimotor integration in MD provides helpful insights for the design of more effective behavioral therapies. PMID:23805090

  15. Cortical Plasticity Induced by Spike-Triggered Microstimulation in Primate Somatosensory Cortex

    PubMed Central

    Song, Weiguo; Kerr, Cliff C.; Lytton, William W.; Francis, Joseph T.

    2013-01-01

    Electrical stimulation of the nervous system for therapeutic purposes, such as deep brain stimulation in the treatment of Parkinson’s disease, has been used for decades. Recently, increased attention has focused on using microstimulation to restore functions as diverse as somatosensation and memory. However, how microstimulation changes the neural substrate is still not fully understood. Microstimulation may cause cortical changes that could either compete with or complement natural neural processes, and could result in neuroplastic changes rendering the region dysfunctional or even epileptic. As part of our efforts to produce neuroprosthetic devices and to further study the effects of microstimulation on the cortex, we stimulated and recorded from microelectrode arrays in the hand area of the primary somatosensory cortex (area 1) in two awake macaque monkeys. We applied a simple neuroprosthetic microstimulation protocol to a pair of electrodes in the area 1 array, using either random pulses or pulses time-locked to the recorded spiking activity of a reference neuron. This setup was replicated using a computer model of the thalamocortical system, which consisted of 1980 spiking neurons distributed among six cortical layers and two thalamic nuclei. Experimentally, we found that spike-triggered microstimulation induced cortical plasticity, as shown by increased unit-pair mutual information, while random microstimulation did not. In addition, there was an increased response to touch following spike-triggered microstimulation, along with decreased neural variability. The computer model successfully reproduced both qualitative and quantitative aspects of the experimental findings. The physiological findings of this study suggest that even simple microstimulation protocols can be used to increase somatosensory information flow. PMID:23472086

  16. Metaplasticity in human primary somatosensory cortex: effects on physiology and tactile perception.

    PubMed

    Jones, Christina B; Lulic, Tea; Bailey, Aaron Z; Mackenzie, Tanner N; Mi, Yi Qun; Tommerdahl, Mark; Nelson, Aimee J

    2016-05-01

    Theta-burst stimulation (TBS) over human primary motor cortex evokes plasticity and metaplasticity, the latter contributing to the homeostatic balance of excitation and inhibition. Our knowledge of TBS-induced effects on primary somatosensory cortex (SI) is limited, and it is unknown whether TBS induces metaplasticity within human SI. Sixteen right-handed participants (6 females, mean age 23 yr) received two TBS protocols [continuous TBS (cTBS) and intermittent TBS (iTBS)] delivered in six different combinations over SI in separate sessions. TBS protocols were delivered at 30 Hz and were as follows: a single cTBS protocol, a single iTBS protocol, cTBS followed by cTBS, iTBS followed by iTBS, cTBS followed by iTBS, and iTBS followed by cTBS. Measures included the amplitudes of the first and second somatosensory evoked potentials (SEPs) via median nerve stimulation, their paired-pulse ratio (PPR), and temporal order judgment (TOJ). Dependent measures were obtained before TBS and at 5, 25, 50, and 90 min following stimulation. Results indicate similar effects following cTBS and iTBS; increased amplitudes of the second SEP and PPR without amplitude changes to SEP 1, and impairments in TOJ. Metaplasticity was observed such that TOJ impairments following a single cTBS protocol were abolished following consecutive cTBS protocols. Additionally, consecutive iTBS protocols altered the time course of effects when compared with a single iTBS protocol. In conclusion, 30-Hz cTBS and iTBS protocols delivered in isolation induce effects consistent with a TBS-induced reduction in intracortical inhibition within SI. Furthermore, cTBS- and iTBS-induced metaplasticity appear to follow homeostatic and nonhomeostatic rules, respectively.

  17. Parkinson's disease accelerates age-related decline in haptic perception by altering somatosensory integration.

    PubMed

    Konczak, Jürgen; Sciutti, Alessandra; Avanzino, Laura; Squeri, Valentina; Gori, Monica; Masia, Lorenzo; Abbruzzese, Giovanni; Sandini, Giulio

    2012-11-01

    This study investigated how Parkinson's disease alters haptic perception and the underlying mechanisms of somatosensory and sensorimotor integration. Changes in haptic sensitivity and acuity (the abilities to detect and to discriminate between haptic stimuli) due to Parkinson's disease were systematically quantified and contrasted to the performance of healthy older and young adults. Using a robotic force environment, virtual contours of various curvatures were presented. Participants explored these contours with their hands and indicated verbally whether they could detect or discriminate between two contours. To understand what aspects of sensory or sensorimotor integration are altered by ageing and disease, we manipulated the sensorimotor aspect of the task: the robot either guided the hand along the contour or the participant actively moved the hand. Active exploration relies on multimodal sensory and sensorimotor integration, while passive guidance only requires sensory integration of proprioceptive and tactile information. The main findings of the study are as follows: first, a decline in haptic precision can already be observed in adults before the age of 70 years. Parkinson's disease may lead to an additional decrease in haptic sensitivity well beyond the levels typically seen in middle-aged and older adults. Second, the haptic deficit in Parkinson's disease is general in nature. It becomes manifest as a decrease in sensitivity and acuity (i.e. a smaller perceivable range and a diminished ability to discriminate between two perceivable haptic stimuli). Third, thresholds during both active and passive exploration are elevated, but not significantly different from each other. That is, active exploration did not enhance the haptic deficit when compared to passive hand motion. This implies that Parkinson's disease affects early stages of somatosensory integration that ultimately have an impact on processes of sensorimotor integration. Our results suggest that

  18. Inhibitory effect of intensity and interstimulus interval of conditioning stimuli on somatosensory evoked magnetic fields.

    PubMed

    Onishi, Hideaki; Sugawara, Kazuhiro; Yamashiro, Koya; Sato, Daisuke; Kirimoto, Hikari; Tamaki, Hiroyuki; Shirozu, Hiroshi; Kameyama, Shigeki

    2016-08-01

    Magnetoencephalography (MEG) recordings were performed to investigate the inhibitory effects of conditioning stimuli with various types of interstimulus intervals (ISIs) or intensities on somatosensory evoked magnetic fields (SEFs) using a 306-ch whole-head MEG system. Twenty-three healthy volunteers participated in this study. Electrical stimuli were applied to the right median nerve at the wrist. Six pulse trains with ISIs of 500 ms were presented in Experiment 1. A paired-pulse paradigm with three kinds of conditioning stimulus (CON) intensities, 500 ms before the test stimulus (TS), was applied in Experiment 2. Finally, three CONs 500 or 1000 ms before TS were presented in Experiment 3. Three main SEF deflections (N20m, P35m, and P60m) were observed, and the source activities of P35m and P60m significantly decreased after the 2nd pulse of a six pulse trains. These source activities also significantly decreased with increasing intensity of CON. In addition, these attenuations of source activities were affected by CON-CON or CON-TS intervals. These results indicated that the source activities were modulated by the intensity and ISIs of CONs. Furthermore, P35m after the stimulation were very sensitive to CONs; however, the attenuation of P60m after the stimulation lasted for a longer period than that of P35m. Our findings suggest that the conditioning stimulation had inhibitory effects on subsequent evoked cortical responses for more than 500 ms. Our results also provide important clues about the nature of short-latency somatosensory responses in human studies. PMID:27319980

  19. The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates

    PubMed Central

    Qi, Hui-Xin; Kaas, Jon H.; Reed, Jamie L.

    2014-01-01

    In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b). However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord injury. PMID:24860443

  20. Metaplasticity in human primary somatosensory cortex: effects on physiology and tactile perception.

    PubMed

    Jones, Christina B; Lulic, Tea; Bailey, Aaron Z; Mackenzie, Tanner N; Mi, Yi Qun; Tommerdahl, Mark; Nelson, Aimee J

    2016-05-01

    Theta-burst stimulation (TBS) over human primary motor cortex evokes plasticity and metaplasticity, the latter contributing to the homeostatic balance of excitation and inhibition. Our knowledge of TBS-induced effects on primary somatosensory cortex (SI) is limited, and it is unknown whether TBS induces metaplasticity within human SI. Sixteen right-handed participants (6 females, mean age 23 yr) received two TBS protocols [continuous TBS (cTBS) and intermittent TBS (iTBS)] delivered in six different combinations over SI in separate sessions. TBS protocols were delivered at 30 Hz and were as follows: a single cTBS protocol, a single iTBS protocol, cTBS followed by cTBS, iTBS followed by iTBS, cTBS followed by iTBS, and iTBS followed by cTBS. Measures included the amplitudes of the first and second somatosensory evoked potentials (SEPs) via median nerve stimulation, their paired-pulse ratio (PPR), and temporal order judgment (TOJ). Dependent measures were obtained before TBS and at 5, 25, 50, and 90 min following stimulation. Results indicate similar effects following cTBS and iTBS; increased amplitudes of the second SEP and PPR without amplitude changes to SEP 1, and impairments in TOJ. Metaplasticity was observed such that TOJ impairments following a single cTBS protocol were abolished following consecutive cTBS protocols. Additionally, consecutive iTBS protocols altered the time course of effects when compared with a single iTBS protocol. In conclusion, 30-Hz cTBS and iTBS protocols delivered in isolation induce effects consistent with a TBS-induced reduction in intracortical inhibition within SI. Furthermore, cTBS- and iTBS-induced metaplasticity appear to follow homeostatic and nonhomeostatic rules, respectively. PMID:26984422

  1. Test-retest reliability of concurrently recorded steady-state and somatosensory evoked potentials in somatosensory sustained spatial attention.

    PubMed

    Pang, Cheuk Yee; Mueller, Matthias M

    2014-07-01

    We investigated the test-retest reliability of sustained spatial attention modulation of steady-state somatosensory evoked potentials (SSSEPs) and the N140 component of the somatosensory evoked potentials (SEPs). Participants attended to one or both hands to perform a target detection task while concurrent mechanical vibrations were presented for 4500ms to both hands in two recording sessions. Results revealed that the amplitude and the attentional modulation of SSSEPs had high test-retest reliability, while the test-retest reliability for the N140 component was low. SSSEPs for stimuli with focused and divided attention had about the same amplitude. For the N140 component only the stimuli with focused attention were significantly enhanced. We found greater habituation effects for the N140 compared to SSSEP amplitudes but attentional modulation was unaffected in both signals. Given the great test-retest reliability of SSSEP amplitude modulation with attention, SSSEPs serve as an excellent tool for studying sustained spatial attention in somatosensation.

  2. Parallel coding schemes of whisker velocity in the rat's somatosensory system.

    PubMed

    Lottem, Eran; Gugig, Erez; Azouz, Rony

    2015-03-15

    The function of rodents' whisker somatosensory system is to transform tactile cues, in the form of vibrissa vibrations, into neuronal responses. It is well established that rodents can detect numerous tactile stimuli and tell them apart. However, the transformation of tactile stimuli obtained through whisker movements to neuronal responses is not well-understood. Here we examine the role of whisker velocity in tactile information transmission and its coding mechanisms. We show that in anaesthetized rats, whisker velocity is related to the radial distance of the object contacted and its own velocity. Whisker velocity is accurately and reliably coded in first-order neurons in parallel, by both the relative time interval between velocity-independent first spike latency of rapidly adapting neurons and velocity-dependent first spike latency of slowly adapting neurons. At the same time, whisker velocity is also coded, although less robustly, by the firing rates of slowly adapting neurons. Comparing first- and second-order neurons, we find similar decoding efficiencies for whisker velocity using either temporal or rate-based methods. Both coding schemes are sufficiently robust and hardly affected by neuronal noise. Our results suggest that whisker kinematic variables are coded by two parallel coding schemes and are disseminated in a similar way through various brain stem nuclei to multiple brain areas.

  3. Overview of existing European food consumption databases: critical aspects in relation to their use for the assessment of dietary exposure to additives, flavourings and residues of food contact materials.

    PubMed

    Le Donne, Cinzia; Piccinelli, Raffaela; Sette, Stefania; Leclercq, Catherine

    2011-03-01

    A critical analysis of existing food consumption databases was performed with particular regard for their current and potential use for the assessment of dietary exposure to additives, flavourings and residues of food contact materials. Within the European Food Consumption Validation project (EFCOVAL), a questionnaire on critical aspects of such datasets was developed and administered to researchers responsible for the collection/analysis of national food consumption data in European countries. Information collected was complemented through a review of the literature and of grey publications in order to provide an inventory of the main food consumption surveys performed in Europe from 1994 to 2007, for a total of 23 countries and 37 surveys. It appeared that existing European food consumption surveys have as a main objective the assessment of nutrient intake in the population. On the other hand, most of the databases were shown to be used also for the purpose of dietary exposure assessment.

  4. Neuromagnetic correlates of adaptive plasticity across the hand-face border in human primary somatosensory cortex.

    PubMed

    Muret, Dollyane; Daligault, Sébastien; Dinse, Hubert R; Delpuech, Claude; Mattout, Jérémie; Reilly, Karen T; Farnè, Alessandro

    2016-04-01

    It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual phenomena such as tactile sensations being referred from the face to the phantom hand. It is also known that transient increase of hand somatosensory inputs, via repetitive somatosensory stimulation (RSS) at a fingertip, induces local somatosensory discriminative improvement accompanied by cortical representational changes in the primary somatosensory cortex (SI). We recently demonstrated that RSS at the tip of the right index finger induces similar training-independent perceptual learning across the hand-face border, improving somatosensory perception at the lips (Muret D, Dinse HR, Macchione S, Urquizar C, Farnè A, Reilly KT.Curr Biol24: R736-R737, 2014). Whether neural plastic changes across the hand-face border accompany such remote and adaptive perceptual plasticity remains unknown. Here we used magnetoencephalography to investigate the electrophysiological correlates underlying RSS-induced behavioral changes across the hand-face border. The results highlight significant changes in dipole location after RSS both for the stimulated finger and for the lips. These findings reveal plastic changes that cross the hand-face border after an increase, instead of a decrease, in somatosensory inputs.

  5. Beta rhythm modulation by speech sounds: somatotopic mapping in somatosensory cortex.

    PubMed

    Bartoli, Eleonora; Maffongelli, Laura; Campus, Claudio; D'Ausilio, Alessandro

    2016-01-01

    During speech listening motor regions are somatotopically activated, resembling the activity that subtends actual speech production, suggesting that motor commands can be retrieved from sensory inputs. Crucially, the efficient motor control of the articulators relies on the accurate anticipation of the somatosensory reafference. Nevertheless, evidence about somatosensory activities elicited by auditory speech processing is sparse. The present work looked for specific interactions between auditory speech presentation and somatosensory cortical information processing. We used an auditory speech identification task with sounds having different place of articulation (bilabials and dentals). We tested whether coupling the auditory task with a peripheral electrical stimulation of the lips would affect the pattern of sensorimotor electroencephalographic rhythms. Peripheral electrical stimulation elicits a series of spectral perturbations of which the beta rebound reflects the return-to-baseline stage of somatosensory processing. We show a left-lateralized and selective reduction in the beta rebound following lip somatosensory stimulation when listening to speech sounds produced with the lips (i.e. bilabials). Thus, the somatosensory processing could not return to baseline due to the recruitment of the same neural resources by speech stimuli. Our results are a clear demonstration that heard speech sounds are somatotopically mapped onto somatosensory cortices, according to place of articulation. PMID:27499204

  6. Beta rhythm modulation by speech sounds: somatotopic mapping in somatosensory cortex

    PubMed Central

    Bartoli, Eleonora; Maffongelli, Laura; Campus, Claudio; D’Ausilio, Alessandro

    2016-01-01

    During speech listening motor regions are somatotopically activated, resembling the activity that subtends actual speech production, suggesting that motor commands can be retrieved from sensory inputs. Crucially, the efficient motor control of the articulators relies on the accurate anticipation of the somatosensory reafference. Nevertheless, evidence about somatosensory activities elicited by auditory speech processing is sparse. The present work looked for specific interactions between auditory speech presentation and somatosensory cortical information processing. We used an auditory speech identification task with sounds having different place of articulation (bilabials and dentals). We tested whether coupling the auditory task with a peripheral electrical stimulation of the lips would affect the pattern of sensorimotor electroencephalographic rhythms. Peripheral electrical stimulation elicits a series of spectral perturbations of which the beta rebound reflects the return-to-baseline stage of somatosensory processing. We show a left-lateralized and selective reduction in the beta rebound following lip somatosensory stimulation when listening to speech sounds produced with the lips (i.e. bilabials). Thus, the somatosensory processing could not return to baseline due to the recruitment of the same neural resources by speech stimuli. Our results are a clear demonstration that heard speech sounds are somatotopically mapped onto somatosensory cortices, according to place of articulation. PMID:27499204

  7. Distinct vestibular effects on early and late somatosensory cortical processing in humans.

    PubMed

    Pfeiffer, Christian; van Elk, Michiel; Bernasconi, Fosco; Blanke, Olaf

    2016-01-15

    In non-human primates several brain areas contain neurons that respond to both vestibular and somatosensory stimulation. In humans, vestibular stimulation activates several somatosensory brain regions and improves tactile perception. However, less is known about the spatio-temporal dynamics of such vestibular-somatosensory interactions in the human brain. To address this issue, we recorded high-density electroencephalography during left median nerve electrical stimulation to obtain Somatosensory Evoked Potentials (SEPs). We analyzed SEPs during vestibular activation following sudden decelerations from constant-velocity (90°/s and 60°/s) earth-vertical axis yaw rotations and SEPs during a non-vestibular control period. SEP analysis revealed two distinct temporal effects of vestibular activation: An early effect (28-32ms post-stimulus) characterized by vestibular suppression of SEP response strength that depended on rotation velocity and a later effect (97-112ms post-stimulus) characterized by vestibular modulation of SEP topographical pattern that was rotation velocity-independent. Source estimation localized these vestibular effects, during both time periods, to activation differences in a distributed cortical network including the right postcentral gyrus, right insula, left precuneus, and bilateral secondary somatosensory cortex. These results suggest that vestibular-somatosensory interactions in humans depend on processing in specific time periods in somatosensory and vestibular cortical regions.

  8. Distinct vestibular effects on early and late somatosensory cortical processing in humans.

    PubMed

    Pfeiffer, Christian; van Elk, Michiel; Bernasconi, Fosco; Blanke, Olaf

    2016-01-15

    In non-human primates several brain areas contain neurons that respond to both vestibular and somatosensory stimulation. In humans, vestibular stimulation activates several somatosensory brain regions and improves tactile perception. However, less is known about the spatio-temporal dynamics of such vestibular-somatosensory interactions in the human brain. To address this issue, we recorded high-density electroencephalography during left median nerve electrical stimulation to obtain Somatosensory Evoked Potentials (SEPs). We analyzed SEPs during vestibular activation following sudden decelerations from constant-velocity (90°/s and 60°/s) earth-vertical axis yaw rotations and SEPs during a non-vestibular control period. SEP analysis revealed two distinct temporal effects of vestibular activation: An early effect (28-32ms post-stimulus) characterized by vestibular suppression of SEP response strength that depended on rotation velocity and a later effect (97-112ms post-stimulus) characterized by vestibular modulation of SEP topographical pattern that was rotation velocity-independent. Source estimation localized these vestibular effects, during both time periods, to activation differences in a distributed cortical network including the right postcentral gyrus, right insula, left precuneus, and bilateral secondary somatosensory cortex. These results suggest that vestibular-somatosensory interactions in humans depend on processing in specific time periods in somatosensory and vestibular cortical regions. PMID:26466979

  9. Augmented Pain Processing in Primary and Secondary Somatosensory Cortex in Fibromyalgia: A Magnetoencephalography Study Using Intra-Epidermal Electrical Stimulation

    PubMed Central

    Lim, Manyoel; Roosink, Meyke; Kim, June Sic; Kim, Hye Won; Lee, Eun Bong; Son, Kyeong Min; Kim, Hyun Ah; Chung, Chun Kee

    2016-01-01

    The aim of this study was to investigate augmented pain processing in the cortical somatosensory system in patients with fibromyalgia (FM). Cortical evoked responses were recorded in FM (n = 19) and healthy subjects (n = 21) using magnetoencephalography after noxious intra-epidermal electrical stimulation (IES) of the hand dorsum (pain rating 6 on a numeric rating scale, perceptually-equivalent). In addition, healthy subjects were stimulated using the amplitude corresponding to the average stimulus intensity rated 6 in patients with FM (intensity-equivalent). Quantitative sensory testing was performed on the hand dorsum or thenar muscle (neutral site) and over the trapezius muscle (tender point), using IES (thresholds, ratings, temporal summation of pain, stimulus-response curve) and mechanical stimuli (threshold, ratings). Increased amplitude of cortical responses was found in patients with FM as compared to healthy subjects. These included the contralateral primary (S1) and bilateral secondary somatosensory cortices (S2) in response to intensity-equivalent stimuli and the contralateral S1 and S2 in response to perceptually-equivalent stimuli. The amplitude of the contralateral S2 response in patients with FM was positively correlated with average pain intensity over the last week. Quantitative sensory testing results showed that patients with FM were more sensitive to painful IES as well as to mechanical stimulation, regardless of whether the stimulation site was the hand or the trapezius muscle. Interestingly, the slope of the stimulus-response relationship as well as temporal summation of pain in response to IES was not different between groups. Together, these results suggest that the observed pain augmentation in response to IES in patients with FM could be due to sensitization or disinhibition of the cortical somatosensory system. Since the S2 has been shown to play a role in higher-order functions, further studies are needed to clarify the role of augmented

  10. Augmented Pain Processing in Primary and Secondary Somatosensory Cortex in Fibromyalgia: A Magnetoencephalography Study Using Intra-Epidermal Electrical Stimulation.

    PubMed

    Lim, Manyoel; Roosink, Meyke; Kim, June Sic; Kim, Hye Won; Lee, Eun Bong; Son, Kyeong Min; Kim, Hyun Ah; Chung, Chun Kee

    2016-01-01

    The aim of this study was to investigate augmented pain processing in the cortical somatosensory system in patients with fibromyalgia (FM). Cortical evoked responses were recorded in FM (n = 19) and healthy subjects (n = 21) using magnetoencephalography after noxious intra-epidermal electrical stimulation (IES) of the hand dorsum (pain rating 6 on a numeric rating scale, perceptually-equivalent). In addition, healthy subjects were stimulated using the amplitude corresponding to the average stimulus intensity rated 6 in patients with FM (intensity-equivalent). Quantitative sensory testing was performed on the hand dorsum or thenar muscle (neutral site) and over the trapezius muscle (tender point), using IES (thresholds, ratings, temporal summation of pain, stimulus-response curve) and mechanical stimuli (threshold, ratings). Increased amplitude of cortical responses was found in patients with FM as compared to healthy subjects. These included the contralateral primary (S1) and bilateral secondary somatosensory cortices (S2) in response to intensity-equivalent stimuli and the contralateral S1 and S2 in response to perceptually-equivalent stimuli. The amplitude of the contralateral S2 response in patients with FM was positively correlated with average pain intensity over the last week. Quantitative sensory testing results showed that patients with FM were more sensitive to painful IES as well as to mechanical stimulation, regardless of whether the stimulation site was the hand or the trapezius muscle. Interestingly, the slope of the stimulus-response relationship as well as temporal summation of pain in response to IES was not different between groups. Together, these results suggest that the observed pain augmentation in response to IES in patients with FM could be due to sensitization or disinhibition of the cortical somatosensory system. Since the S2 has been shown to play a role in higher-order functions, further studies are needed to clarify the role of augmented

  11. Listening to Another Sense: Somatosensory Integration in the Auditory System

    PubMed Central

    Wu, Calvin; Stefanescu, Roxana A.; Martel, David T.

    2014-01-01

    Conventionally, sensory systems are viewed as separate entities, each with its own physiological process serving a different purpose. However, many functions require integrative inputs from multiple sensory systems, and sensory intersection and convergence occur throughout the central nervous system. The neural processes for hearing perception undergo significant modulation by the two other major sensory systems, vision and somatosensation. This synthesis occurs at every level of the ascending auditory pathway: the cochlear nucleus, inferior colliculus, medial geniculate body, and the auditory cortex. In this review, we explore the process of multisensory integration from 1) anatomical (inputs and connections), 2) physiological (cellular responses), 3) functional, and 4) pathological aspects. We focus on the convergence between auditory and somatosensory inputs in each ascending auditory station. This review highlights the intricacy of sensory processing, and offers a multisensory perspective regarding the understanding of sensory disorders. PMID:25526698

  12. Somatosensory and hypothalamic inhibitions of baroreflex vagal bradycardia in rats.

    PubMed

    Nosaka, S; Nakase, N; Murata, K

    1989-04-01

    Somatosensory and forebrain mechanisms inhibiting arterial baroreflexes were investigated in chloralose-urethane anesthetized and artificially ventilated rats. Electrical stimulation of the sciatic nerve (ScN) and the hypothalamic pressor area (HP) suppressed baroreflex vagal bradycardia (BVB) and hypotension provoked by electrical stimulation of the aortic depressor nerve (ADN). Suppression of BVB was more marked, but inhibitory potencies of ScN and HP were not different. These two inhibitions were considered to have a functional implication in common, since both were accompanied by increase in hindlimb vascular conductance. A variety of experiments were conducted to localize the target site of ScN and HP inhibitions of BVB. Either ScN or HP stimulations was without effect on antidromic compound spike potentials along ADN evoked by microstimulation of the nucleus tractus solitarius (NTS), precluding the possibility of these inhibitions being presynaptic. Both ScN and HP stimulation suppressed ADN-induced field potentials in the NA region which provoked vagal bradycardia upon microstimulation, but failed to affect ADN-induced responses, either field or unitary, in the NTS region. Antidromic unitary responses in the NA region to vagus cardiac branch stimulation were suppressed by ScN and HP stimulations in NTS-lesioned rats. Intracisternal bicuculline, a GABA antagonist, was found to abolish both ScN and HP inhibitions of BVB, while intracisternal muscimol, a GABA agonist, eliminated bradycardia. These findings suggest that somatosensory and forebrain inhibition of BVB occur principally at the preganglionic cell level and are probably mediated by a GABAergic mechanism. PMID:2726429

  13. Early somatosensory processing in individuals at risk for developing psychoses

    PubMed Central

    Hagenmuller, Florence; Heekeren, Karsten; Theodoridou, Anastasia; Walitza, Susanne; Haker, Helene; Rössler, Wulf; Kawohl, Wolfram

    2014-01-01

    Human cortical somatosensory evoked potentials (SEPs) allow an accurate investigation of thalamocortical and early cortical processing. SEPs reveal a burst of superimposed early (N20) high-frequency oscillations around 600 Hz. Previous studies reported alterations of SEPs in patients with schizophrenia. This study addresses the question whether those alterations are also observable in populations at risk for developing schizophrenia or bipolar disorders. To our knowledge to date, this is the first study investigating SEPs in a population at risk for developing psychoses. Median nerve SEPs were investigated using multichannel EEG in individuals at risk for developing bipolar disorders (n = 25), individuals with high-risk status (n = 59) and ultra-high-risk status for schizophrenia (n = 73) and a gender and age-matched control group (n = 45). Strengths and latencies of low- and high-frequency components as estimated by dipole source analysis were compared between groups. Low- and high-frequency source activity was reduced in both groups at risk for schizophrenia, in comparison to the group at risk for bipolar disorders. HFO amplitudes were also significant reduced in subjects with high-risk status for schizophrenia compared to healthy controls. These differences were accentuated among cannabis non-users. Reduced N20 source strengths were related to higher positive symptom load. These results suggest that the risk for schizophrenia, in contrast to bipolar disorders, may involve an impairment of early cerebral somatosensory processing. Neurophysiologic alterations in schizophrenia precede the onset of initial psychotic episode and may serve as indicator of vulnerability for developing schizophrenia. PMID:25309363

  14. Early somatosensory processing in individuals at risk for developing psychoses.

    PubMed

    Hagenmuller, Florence; Heekeren, Karsten; Theodoridou, Anastasia; Walitza, Susanne; Haker, Helene; Rössler, Wulf; Kawohl, Wolfram

    2014-01-01

    Human cortical somatosensory evoked potentials (SEPs) allow an accurate investigation of thalamocortical and early cortical processing. SEPs reveal a burst of superimposed early (N20) high-frequency oscillations around 600 Hz. Previous studies reported alterations of SEPs in patients with schizophrenia. This study addresses the question whether those alterations are also observable in populations at risk for developing schizophrenia or bipolar disorders. To our knowledge to date, this is the first study investigating SEPs in a population at risk for developing psychoses. Median nerve SEPs were investigated using multichannel EEG in individuals at risk for developing bipolar disorders (n = 25), individuals with high-risk status (n = 59) and ultra-high-risk status for schizophrenia (n = 73) and a gender and age-matched control group (n = 45). Strengths and latencies of low- and high-frequency components as estimated by dipole source analysis were compared between groups. Low- and high-frequency source activity was reduced in both groups at risk for schizophrenia, in comparison to the group at risk for bipolar disorders. HFO amplitudes were also significant reduced in subjects with high-risk status for schizophrenia compared to healthy controls. These differences were accentuated among cannabis non-users. Reduced N20 source strengths were related to higher positive symptom load. These results suggest that the risk for schizophrenia, in contrast to bipolar disorders, may involve an impairment of early cerebral somatosensory processing. Neurophysiologic alterations in schizophrenia precede the onset of initial psychotic episode and may serve as indicator of vulnerability for developing schizophrenia. PMID:25309363

  15. Atypical visual and somatosensory adaptation in schizophrenia-spectrum disorders

    PubMed Central

    Andrade, G N; Butler, J S; Peters, G A; Molholm, S; Foxe, J J

    2016-01-01

    Neurophysiological investigations in patients with schizophrenia consistently show early sensory processing deficits in the visual system. Importantly, comparable sensory deficits have also been established in healthy first-degree biological relatives of patients with schizophrenia and in first-episode drug-naive patients. The clear implication is that these measures are endophenotypic, related to the underlying genetic liability for schizophrenia. However, there is significant overlap between patient response distributions and those of healthy individuals without affected first-degree relatives. Here we sought to develop more sensitive measures of sensory dysfunction in this population, with an eye to establishing endophenotypic markers with better predictive capabilities. We used a sensory adaptation paradigm in which electrophysiological responses to basic visual and somatosensory stimuli presented at different rates (ranging from 250 to 2550 ms interstimulus intervals, in blocked presentations) were compared. Our main hypothesis was that adaptation would be substantially diminished in schizophrenia, and that this would be especially prevalent in the visual system. High-density event-related potential recordings showed amplitude reductions in sensory adaptation in patients with schizophrenia (N=15 Experiment 1, N=12 Experiment 2) compared with age-matched healthy controls (N=15 Experiment 1, N=12 Experiment 2), and this was seen for both sensory modalities. At the individual participant level, reduced adaptation was more robust for visual compared with somatosensory stimulation. These results point to significant impairments in short-term sensory plasticity across sensory modalities in schizophrenia. These simple-to-execute measures may prove valuable as candidate endophenotypes and will bear follow-up in future work. PMID:27163205

  16. Solar cell with back side contacts

    DOEpatents

    Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J; Wanlass, Mark Woodbury; Clews, Peggy J

    2013-12-24

    A III-V solar cell is described herein that includes all back side contacts. Additionally, the positive and negative electrical contacts contact compoud semiconductor layers of the solar cell other than the absorbing layer of the solar cell. That is, the positive and negative electrical contacts contact passivating layers of the solar cell.

  17. Self-injurious behaviours are associated with alterations in the somatosensory system in children with autism spectrum disorder.

    PubMed

    Duerden, Emma G; Card, Dallas; Roberts, S Wendy; Mak-Fan, Kathleen M; Chakravarty, M Mallar; Lerch, Jason P; Taylor, Margot J

    2014-07-01

    Children with autism spectrum disorder (ASD) frequently engage in self-injurious behaviours, often in the absence of reporting pain. Previous research suggests that altered pain sensitivity and repeated exposure to noxious stimuli are associated with morphological changes in somatosensory and limbic cortices. Further evidence from postmortem studies with self-injurious adults has indicated alterations in the structure and organization of the temporal lobes; however, the effect of self-injurious behaviour on cortical development in children with ASD has not yet been determined. Thirty children and adolescents (mean age = 10.6 ± 2.5 years; range 7-15 years; 29 males) with a clinical diagnosis of ASD and 30 typically developing children (N = 30, mean age = 10.7 ± 2.5 years; range 7-15 years, 26 males) underwent T1-weighted magnetic resonance and diffusion tensor imaging. No between-group differences were seen in cerebral volume, surface area or cortical thickness. Within the ASD group, self-injury scores negatively correlated with thickness in the right superior parietal lobule t = 6.3, p < 0.0001, bilateral primary somatosensory cortices (SI) (right: t = 4.4, p = 0.02; left: t = 4.48, p = 0.004) and the volume of the left ventroposterior (VP) nucleus of the thalamus (r = -0.52, p = 0.008). Based on these findings, we performed an atlas-based region-of-interest diffusion tensor imaging analysis between SI and the VP nucleus and found that children who engaged in self-injury had significantly lower fractional anisotropy (r = -0.4, p = 0.04) and higher mean diffusivity (r = 0.5, p = 0.03) values in the territory of the left posterior limb of the internal capsule. Additionally, greater incidence of self-injury was associated with increased radial diffusivity values in bilateral posterior limbs of the internal capsule (left: r = 0.5, p = 0.02; right: r = 0.5, p = 0.009) and corona radiata (left: r = 0.6, p = 0.005; right: r = 0.5, p = 0.009). Results indicate that self

  18. Somatosensory Representations Link the Perception of Emotional Expressions and Sensory Experience123

    PubMed Central

    2016-01-01

    Abstract Studies of human emotion perception have linked a distributed set of brain regions to the recognition of emotion in facial, vocal, and body expressions. In particular, lesions to somatosensory cortex in the right hemisphere have been shown to impair recognition of facial and vocal expressions of emotion. Although these findings suggest that somatosensory cortex represents body states associated with distinct emotions, such as a furrowed brow or gaping jaw, functional evidence directly linking somatosensory activity and subjective experience during emotion perception is critically lacking. Using functional magnetic resonance imaging and multivariate decoding techniques, we show that perceiving vocal and facial expressions of emotion yields hemodynamic activity in right somatosensory cortex that discriminates among emotion categories, exhibits somatotopic organization, and tracks self-reported sensory experience. The findings both support embodied accounts of emotion and provide mechanistic insight into how emotional expressions are capable of biasing subjective experience in those who perceive them. PMID:27280154

  19. Native Piezo2 Interactomics Identifies Pericentrin as a Novel Regulator of Piezo2 in Somatosensory Neurons.

    PubMed

    Narayanan, Pratibha; Sondermann, Julia; Rouwette, Tom; Karaca, Samir; Urlaub, Henning; Mitkovski, Mišo; Gomez-Varela, David; Schmidt, Manuela

    2016-08-01

    The ability of somatosensory neurons to perceive mechanical stimuli relies on specialized mechanotransducing proteins and their molecular environment. Only recently has the identity of a major transducer of mechanical forces in vertebrates been revealed by the discovery of Piezo2. Further work has established its pivotal role for innocuous touch in mice. Therefore, Piezo2 offers a unique platform for the molecular investigation of somatosensory mechanosensation. We performed a mass spectrometry-based interactomics screen on native Piezo2 in somatosensory neurons of mouse dorsal root ganglia (DRG). Stringent and quantitative data analysis yielded the identity of 36 novel binding partners of Piezo2. The biological significance of this data set is reflected by functional experiments demonstrating a role for Pericentrin in modulating Piezo2 activity and membrane expression in somatosensory neurons. Collectively, our findings provide a framework for understanding Piezo2 physiology and serve as a rich resource for the molecular dissection of mouse somatosensation. PMID:27345391

  20. Native Piezo2 Interactomics Identifies Pericentrin as a Novel Regulator of Piezo2 in Somatosensory Neurons.

    PubMed

    Narayanan, Pratibha; Sondermann, Julia; Rouwette, Tom; Karaca, Samir; Urlaub, Henning; Mitkovski, Mišo; Gomez-Varela, David; Schmidt, Manuela

    2016-08-01

    The ability of somatosensory neurons to perceive mechanical stimuli relies on specialized mechanotransducing proteins and their molecular environment. Only recently has the identity of a major transducer of mechanical forces in vertebrates been revealed by the discovery of Piezo2. Further work has established its pivotal role for innocuous touch in mice. Therefore, Piezo2 offers a unique platform for the molecular investigation of somatosensory mechanosensation. We performed a mass spectrometry-based interactomics screen on native Piezo2 in somatosensory neurons of mouse dorsal root ganglia (DRG). Stringent and quantitative data analysis yielded the identity of 36 novel binding partners of Piezo2. The biological significance of this data set is reflected by functional experiments demonstrating a role for Pericentrin in modulating Piezo2 activity and membrane expression in somatosensory neurons. Collectively, our findings provide a framework for understanding Piezo2 physiology and serve as a rich resource for the molecular dissection of mouse somatosensation.

  1. Subjective Somatosensory Experiences Disclosed by Focused Attention: Cortical-Hippocampal-Insular and Amygdala Contributions

    PubMed Central

    Bauer, Clemens C. C.; Barrios, Fernando A.; Díaz, José-Luis

    2014-01-01

    In order to explore the neurobiological foundations of qualitative subjective experiences, the present study was designed to correlate objective third-person brain fMRI measures with subjective first-person identification and scaling of local, subtle, and specific somatosensory sensations, obtained directly after the imaging procedure. Thus, thirty-four volunteers were instructed to focus and sustain their attention to either provoked or spontaneous sensations of each thumb during the fMRI procedure. By means of a Likert scale applied immediately afterwards, the participants recalled and evaluated the intensity of their attention and identified specific somatosensory sensations (e.g. pulsation, vibration, heat). Using the subject's subjective scores as covariates to model both attention intensity and general somatosensory experiences regressors, the whole-brain random effect analyses revealed activations in the frontopolar prefrontal cortex (BA10), primary somatosensory cortex (BA1), premotor cortex (BA 6), precuneus (BA 7), temporopolar cortex (BA 38), inferior parietal lobe (BA 39), hippocampus, insula and amygdala. Furthermore, BA10 showed differential activity, with ventral BA10 correlating exclusively with attention (r(32) = 0.54, p = 0.0013) and dorsal BA10 correlating exclusively with somatosensory sensation (r(32) = 0.46, p = 0.007). All other reported brain areas showed significant positive correlations solely with subjective somatosensory experiences reports. These results provide evidence that the frontopolar prefrontal cortex has dissociable functions depending on specific cognitive demands; i.e. the dorsal portion of the frontopolar prefrontal cortex in conjunction with primary somatosensory cortex, temporopolar cortex, inferior parietal lobe, hippocampus, insula and amygdala are involved in the processing of spontaneous general subjective somatosensory experiences disclosed by focused and sustained attention. PMID:25166875

  2. Somatosensory Experiences with Action Modulate Alpha and Beta Power during Subsequent Action Observation

    PubMed Central

    Quandt, Lorna C.; Marshall, Peter J.; Bouquet, Cedric A.; Shipley, Thomas F.

    2013-01-01

    How does prior experience with action change how we perceive a similar action performed by someone else? Previous research has examined the role of sensorimotor and visual experiences in action mirroring during subsequent observation, but the contribution of somatosensory experiences to this effect has not been adequately examined. The current study tests whether prior somatosensory stimulation experienced during action production modulates brain activity during observation of similar actions being performed by others. Specifically, changes in alpha- and beta-range oscillations in the electroencephalogram (EEG) during observation of reaching actions were examined in relation to the observer’s own prior experience of somatosensory stimulation while carrying out similar actions. Analyses revealed that alpha power over central electrodes was significantly decreased during observation of an action expected to result in somatosensory stimulation. Conversely, beta power was increased when an observed action was expected to result in somatosensory stimulation. These results suggest that somatosensory experiences may uniquely contribute to the way in which we process others people’s actions. PMID:23994217

  3. Somatosensory assessment and conditioned pain modulation in temporomandibular disorders pain patients.

    PubMed

    Kothari, Simple Futarmal; Baad-Hansen, Lene; Oono, Yuka; Svensson, Peter

    2015-12-01

    The pathophysiology and underlying pain mechanisms of temporomandibular disorders (TMD) are poorly understood. The aims were to assess somatosensory function at the temporomandibular joints (TMJs) and to examine whether conditioned pain modulation (CPM) differs between TMD pain patients (n = 34) and healthy controls (n = 34). Quantitative sensory testing was used to assess the somatosensory function. Z-scores were calculated for patients based on reference data. Conditioned pain modulation was tested by comparing pressure pain thresholds (PPTs) before, during, and after the application of painful and nonpainful cold stimuli. Pressure pain thresholds were measured at the most painful TMJ and thenar muscle (control). Data were analyzed with analyses of variance. Most (85.3%) of the patients exhibited at least 1 or more somatosensory abnormalities at the most painful TMJ with somatosensory gain with regard to PPT and punctate mechanical pain stimuli, and somatosensory loss with regard to mechanical detection and vibration detection stimuli as the most frequent abnormalities. There was a significant CPM effect (increased PPT) at both test sites during painful cold application in healthy controls and patients (P < 0.001). There was no significant difference in the relative CPM effect during painful cold application between groups (P = 0.227). In conclusion, somatosensory abnormalities were commonly detected in TMD pain patients and CPM effects were similar in TMD pain patients and healthy controls. PMID:26307861

  4. Somatosensory assessment and conditioned pain modulation in temporomandibular disorders pain patients.

    PubMed

    Kothari, Simple Futarmal; Baad-Hansen, Lene; Oono, Yuka; Svensson, Peter

    2015-12-01

    The pathophysiology and underlying pain mechanisms of temporomandibular disorders (TMD) are poorly understood. The aims were to assess somatosensory function at the temporomandibular joints (TMJs) and to examine whether conditioned pain modulation (CPM) differs between TMD pain patients (n = 34) and healthy controls (n = 34). Quantitative sensory testing was used to assess the somatosensory function. Z-scores were calculated for patients based on reference data. Conditioned pain modulation was tested by comparing pressure pain thresholds (PPTs) before, during, and after the application of painful and nonpainful cold stimuli. Pressure pain thresholds were measured at the most painful TMJ and thenar muscle (control). Data were analyzed with analyses of variance. Most (85.3%) of the patients exhibited at least 1 or more somatosensory abnormalities at the most painful TMJ with somatosensory gain with regard to PPT and punctate mechanical pain stimuli, and somatosensory loss with regard to mechanical detection and vibration detection stimuli as the most frequent abnormalities. There was a significant CPM effect (increased PPT) at both test sites during painful cold application in healthy controls and patients (P < 0.001). There was no significant difference in the relative CPM effect during painful cold application between groups (P = 0.227). In conclusion, somatosensory abnormalities were commonly detected in TMD pain patients and CPM effects were similar in TMD pain patients and healthy controls.

  5. Reduction of Pain Sensitivity After Somatosensory Therapy in Adults with Cerebral Palsy

    PubMed Central

    Riquelme, Inmaculada; Zamorano, Anna; Montoya, Pedro

    2013-01-01

    Objective: Pain and deficits in somatosensory processing seem to play a relevant role in cerebral palsy (CP). Rehabilitation techniques based on neuroplasticity mechanisms may induce powerful changes in the organization of the primary somatosensory cortex and have been proved to reduce levels of pain and discomfort in neurological pathologies. However, little is known about the efficacy of such interventions for pain sensitivity in CP individuals. Methods: Adults with CP participated in the study and were randomly assigned to the intervention (n = 17) or the control group (n = 20). The intervention group received a somatosensory therapy including four types of exercises (touch, proprioception, vibration, and stereognosis). All participants were asked to continue their standardized motor therapy during the study period. Several somatosensory (pain and touch thresholds, stereognosis, proprioception, texture recognition) and motor parameters (fine motor skills) were assessed before, immediately after and 3 months after the therapy (follow-up). Results: Participants of the intervention group showed a significant reduction on pain sensitivity after treatment and at follow-up after 3 months, whereas participants in the control group displayed increasing pain sensitivity over time. No improvements were found on touch sensitivity, proprioception, texture recognition, or fine motor skills. Conclusion: Data suggest the possibility that somatosensory therapy was effective in eliciting changes in central somatosensory processing. This hypothesis may have implications for future neuromodulatory treatment of pain complaints in children and adults with CP. PMID:23805086

  6. Granger causal time-dependent source connectivity in the somatosensory network

    NASA Astrophysics Data System (ADS)

    Gao, Lin; Sommerlade, Linda; Coffman, Brian; Zhang, Tongsheng; Stephen, Julia M.; Li, Dichen; Wang, Jue; Grebogi, Celso; Schelter, Bjoern

    2015-05-01

    Exploration of transient Granger causal interactions in neural sources of electrophysiological activities provides deeper insights into brain information processing mechanisms. However, the underlying neural patterns are confounded by time-dependent dynamics, non-stationarity and observational noise contamination. Here we investigate transient Granger causal interactions using source time-series of somatosensory evoked magnetoencephalographic (MEG) elicited by air puff stimulation of right index finger and recorded using 306-channel MEG from 21 healthy subjects. A new time-varying connectivity approach, combining renormalised partial directed coherence with state space modelling, is employed to estimate fast changing information flow among the sources. Source analysis confirmed that somatosensory evoked MEG was mainly generated from the contralateral primary somatosensory cortex (SI) and bilateral secondary somatosensory cortices (SII). Transient Granger causality shows a serial processing of somatosensory information, 1) from contralateral SI to contralateral SII, 2) from contralateral SI to ipsilateral SII, 3) from contralateral SII to contralateral SI, and 4) from contralateral SII to ipsilateral SII. These results are consistent with established anatomical connectivity between somatosensory regions and previous source modeling results, thereby providing empirical validation of the time-varying connectivity analysis. We argue that the suggested approach provides novel information regarding transient cortical dynamic connectivity, which previous approaches could not assess.

  7. Development of Human Somatosensory Cortical Functions - What have We Learned from Magnetoencephalography: A Review.

    PubMed

    Nevalainen, Päivi; Lauronen, Leena; Pihko, Elina

    2014-01-01

    The mysteries of early development of cortical processing in humans have started to unravel with the help of new non-invasive brain research tools like multichannel magnetoencephalography (MEG). In this review, we evaluate, within a wider neuroscientific and clinical context, the value of MEG in studying normal and disturbed functional development of the human somatosensory system. The combination of excellent temporal resolution and good localization accuracy provided by MEG has, in the case of somatosensory studies, enabled the differentiation of activation patterns from the newborn's primary (SI) and secondary somatosensory (SII) areas. Furthermore, MEG has shown that the functioning of both SI and SII in newborns has particular immature features in comparison with adults. In extremely preterm infants, the neonatal MEG response from SII also seems to potentially predict developmental outcome: those lacking SII responses at term show worse motor performance at age 2 years than those with normal SII responses at term. In older children with unilateral early brain lesions, bilateral alterations in somatosensory cortical activation detected in MEG imply that the impact of a localized insult may have an unexpectedly wide effect on cortical somatosensory networks. The achievements over the last decade show that MEG provides a unique approach for studying the development of the somatosensory system and its disturbances in childhood. MEG well complements other neuroimaging methods in studies of cortical processes in the developing brain.

  8. Granger causal time-dependent source connectivity in the somatosensory network.

    PubMed

    Gao, Lin; Sommerlade, Linda; Coffman, Brian; Zhang, Tongsheng; Stephen, Julia M; Li, Dichen; Wang, Jue; Grebogi, Celso; Schelter, Bjoern

    2015-05-21

    Exploration of transient Granger causal interactions in neural sources of electrophysiological activities provides deeper insights into brain information processing mechanisms. However, the underlying neural patterns are confounded by time-dependent dynamics, non-stationarity and observational noise contamination. Here we investigate transient Granger causal interactions using source time-series of somatosensory evoked magnetoencephalographic (MEG) elicited by air puff stimulation of right index finger and recorded using 306-channel MEG from 21 healthy subjects. A new time-varying connectivity approach, combining renormalised partial directed coherence with state space modelling, is employed to estimate fast changing information flow among the sources. Source analysis confirmed that somatosensory evoked MEG was mainly generated from the contralateral primary somatosensory cortex (SI) and bilateral secondary somatosensory cortices (SII). Transient Granger causality shows a serial processing of somatosensory information, 1) from contralateral SI to contralateral SII, 2) from contralateral SI to ipsilateral SII, 3) from contralateral SII to contralateral SI, and 4) from contralateral SII to ipsilateral SII. These results are consistent with established anatomical connectivity between somatosensory regions and previous source modeling results, thereby providing empirical validation of the time-varying connectivity analysis. We argue that the suggested approach provides novel information regarding transient cortical dynamic connectivity, which previous approaches could not assess.

  9. Transcranial magnetic stimulation techniques to study the somatosensory system: research applications.

    PubMed

    Staines, W Richard; Bolton, David A E

    2013-01-01

    The introduction of brain stimulation research techniques such as transcranial magnetic stimulation (TMS) has greatly advanced the understanding of the somatosensory system in humans. Over the last several years, several studies have focused on applying TMS in a variety of contexts to alter transiently the excitability of the somatosensory cortex or regions that project to it and exert some control over its activity in specific behavioral contexts. Specific foci that are discussed in this chapter are methods of repetitive TMS, including theta-burst protocols, delivered to the primary somatosensory cortex that have been shown to affect behavioral indices of somatic sensation such as tactile perception. Similar stimulation techniques can also be applied to distant areas that interact with and modulate activity in somatosensory cortex (i.e., attentional or motor networks). For example, suppression of the dorsolateral prefrontal cortex modifies the attention-modulation of somatosensory information in modality-specific cortices. Overall this chapter is focused on understanding the interaction of activity in systems that function with the somatosensory system in behavioral contexts. These include systems such as those that control attention, whether sustained or selective between sensory modalities, or those that control movement based on targets present in other sensory systems. PMID:24112932

  10. Fragrance allergic contact dermatitis.

    PubMed

    Cheng, Judy; Zug, Kathryn A

    2014-01-01

    Fragrances are a common cause of allergic contact dermatitis in Europe and in North America. They can affect individuals at any age and elicit a spectrum of reactions from contact urticaria to systemic contact dermatitis. Growing recognition of the widespread use of fragrances in modern society has fueled attempts to prevent sensitization through improved allergen identification, labeling, and consumer education. This review provides an overview and update on fragrance allergy. Part 1 discusses the epidemiology and evaluation of suspected fragrance allergy. Part 2 reviews screening methods, emerging fragrance allergens, and management of patients with fragrance contact allergy. This review concludes by examining recent legislation on fragrances and suggesting potential additions to screening series to help prevent and detect fragrance allergy.

  11. Does somatosensory discrimination activate different brain areas in children with unilateral cerebral palsy compared to typically developing children? An fMRI study.

    PubMed

    Van de Winckel, Ann; Verheyden, Geert; Wenderoth, Nici; Peeters, Ron; Sunaert, Stefan; Van Hecke, Wim; De Cock, Paul; Desloovere, Kaat; Eyssen, Maria; Feys, Hilde

    2013-05-01

    Aside from motor impairment, many children with unilateral cerebral palsy (CP) experience altered tactile, proprioceptive, and kinesthetic awareness. Sensory deficits are addressed in rehabilitation programs, which include somatosensory discrimination exercises. In contrast to adult stroke patients, data on brain activation, occurring during somatosensory discrimination exercises, are lacking in CP children. Therefore, this study investigated brain activation with functional magnetic resonance imaging (fMRI) during passively guided somatosensory discrimination exercises in 18 typically developing children (TD) (age, M=14 ± 1.92 years; 11 girls) and 16 CP children (age, M=15 ± 2.54 years; 8 girls). The demographic variables between both groups were not statistically different. An fMRI compatible robot guided the right index finger and performed pairs of unfamiliar geometric shapes in the air, which were judged on their equality. The control condition comprised discrimination of music fragments. Both groups exhibited significant activation (FDR, p<.05) in frontoparietal, temporal, cerebellar areas, and insula, similar to studies in adults. The frontal areas encompassed ventral premotor areas, left postcentral gyrus, and precentral gyrus; additional supplementary motor area (SMA proper) activation in TD; as well as dorsal premotor, and parietal operculum recruitment in CP. On uncorrected level, p<.001, TD children revealed more left frontal lobe, and right cerebellum activation, compared to CP children. Conversely, CP children activated the left dorsal cingulate gyrus to a greater extent than TD children. These data provide incentives to investigate the effect of somatosensory discrimination during rehabilitation in CP, on clinical outcome and brain plasticity. PMID:23500165

  12. Individual differences in cortical connections of somatosensory cortex are associated with parental rearing style in prairie voles (Microtus ochrogaster)

    PubMed Central

    Seelke, Adele M. H.; Perkeybile, Allison M.; Grunewald, Rebecca; Bales, Karen L.; Krubitzer, Leah A.

    2015-01-01

    Early life sensory experiences have a profound effect on brain organization, connectivity and subsequent behavior. In most mammals, the earliest sensory inputs are delivered to the developing brain through tactile contact with the parents, especially the mother. Prairie voles (Microtus ochrogaster) are monogamous and, like humans, are biparental. Within the normal prairie vole population, both the type and amount of interactions, particularly tactile contact, that parents have with their offspring varies. The question is whether these early and pervasive differences in tactile stimulation and social experience between parent and offspring are manifest in differences in cortical organization and connectivity. To address this question we examined the cortical and callosal connections of the primary somatosensory area (S1) in high contact (HC) and low contact (LC) offspring using neuroanatomical tracing techniques. Injection sites within S1 were matched so that direct comparisons between these two groups could be made. We observed several important differences between these groups. The first was that HC offspring had a greater density of intrinsic connections within S1 compared to LC offspring. The HC offspring had a more restricted pattern of ipsilateral connections while LC offspring had dense connections with areas of parietal and frontal cortex that were more widespread. Finally, LC offspring had a broader distribution of callosal connections than HC offspring and a significantly higher percentage of callosal labeled neurons. To date, this is the first study that examines individual differences in cortical connections and suggests that they may be related to natural differences in parental rearing styles associated with tactile contact. PMID:26101098

  13. Contact hysteroscopy.

    PubMed

    Baggish, M S; Barbot, J

    1983-06-01

    In 1907 innovations in optics and illumination made by Maximilian Nitze were applied to hysteroscopy by Charles David, who wrote a treatise of hysteroscopy. David improved illumination by placing an electric incandescent bulb at the intrauterine end of his endoscope and also sealed the distal end of the tube with a piece of glass. The history of the contact endoscope that the authors personally used is connected to the invention by Vulmiere (1952) of a revolutionary illumination process in endoscopy--the "cold light" process. The components of cold light consist of a powerful external light source that is transmitted via a special optical guide into the endometrial cavity. The 1st application of his principle (1963) was an optical trochar contained in a metallic sheath. This simple endoscope was perfected, and in 1973 Barbot and Parent, in France, began to use it to examine the uterine cavity. Discussion focuses on methods, instrumentation, method for examination (grasping the instrument, setup, light source, anesthesia, dilatation, technique, and normal endometrium); cervical neoplasia; nonneoplastic lesions of the endometrium (endometrial polyp, submucous myoma, endometrial hyperplasia); intrauterine device localization; neoplastic lesions of the endometrium; precursors (adenocarcinoma); hysteroscopy in pregnancy (embryoscopy, hydatidiform mole, postpartum hemorrhage, incomplete abortion, spontaneous abortion, induced abortions, and amnioscopy); and examinations of children and infants. The contact endoscope must make light contact with the structure to be viewed. The principles of contact endoscopy depend on an interpretation of color, contour, vascular pattern, and a sense of touch. These are computed together and a diagnosis is made on the basis of previously learned clinical pathologic correlations. The contact endoscope is composed of 3 parts: an optical guide; a cylindric chamber that collects and traps ambient light; and a magnifying eyepiece. The phase of

  14. A New Measure for Monitoring Intraoperative Somatosensory Evoked Potentials

    PubMed Central

    Jin, Seung-Hyun; Kim, Jeong Eun; Choi, Young Doo

    2014-01-01

    Objective To propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study. Methods The proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included. Results We found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery. Conclusion Our results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring. PMID:25628803

  15. Widespread somatosensory sensitivity in naturally occurring canine model of osteoarthritis

    PubMed Central

    Knazovicky, David; Helgeson, Erika S.; Case, Beth; Gruen, Margaret E.; Maixner, William; Lascelles, B. Duncan X.

    2016-01-01

    Abstract Osteoarthritis (OA)-associated pain is a leading cause of disability. Central sensitization (CS), as a result of OA, is recognized as an important facet of human patients' chronic pain and has been measured in people using quantitative sensory testing (QST) testing. The spontaneous canine OA model has been suggested as a good translational model, but CS has not been explored in this model. In this study, QST was performed on dogs with and without spontaneous hip or stifle OA to determine whether OA is associated with CS in this model. Mechanical (von Frey and blunt pressure) and thermal (hot and cold) sensory thresholds obtained in dogs with chronic OA-associated pain (n = 31) were compared with those of normal dogs (n = 23). Dogs were phenotyped and joint-pain scored, and testing was performed at the OA-affected joint, cranial tibial muscle, and dorsal metatarsal region. QST summary data were evaluated using mixed-effect models to understand the influence of OA status and covariates, and dogs with OA and control dogs were compared. The presence of OA was strongly associated with hyperalgesia across all QST modalities at the index joint, cranial tibial muscle, and metatarsal site. Mechanical QST scores were significantly moderately negatively correlated with total joint-pain scores. The spontaneous canine OA model is associated with somatosensory sensitivity, likely indicative of CS. These data further validate the canine spontaneous OA model as an appropriate model of the human OA pain condition. PMID:26901805

  16. Quantitative methods for somatosensory evaluation in atypical odontalgia.

    PubMed

    Porporatti, André Luís; Costa, Yuri Martins; Stuginski-Barbosa, Juliana; Bonjardim, Leonardo Rigoldi; Conti, Paulo César Rodrigues; Svensson, Peter

    2015-01-01

    A systematic review was conducted to identify reliable somatosensory evaluation methods for atypical odontalgia (AO) patients. The computerized search included the main databases (MEDLINE, EMBASE, and Cochrane Library). The studies included used the following quantitative sensory testing (QST) methods: mechanical detection threshold (MDT), mechanical pain threshold (MPT) (pinprick), pressure pain threshold (PPT), dynamic mechanical allodynia with a cotton swab (DMA1) or a brush (DMA2), warm detection threshold (WDT), cold detection threshold (CDT), heat pain threshold (HPT), cold pain detection (CPT), and/or wind-up ratio (WUR). The publications meeting the inclusion criteria revealed that only mechanical allodynia tests (DMA1, DMA2, and WUR) were significantly higher and pain threshold tests to heat stimulation (HPT) were significantly lower in the affected side, compared with the contralateral side, in AO patients; however, for MDT, MPT, PPT, CDT, and WDT, the results were not significant. These data support the presence of central sensitization features, such as allodynia and temporal summation. In contrast, considerable inconsistencies between studies were found when AO patients were compared with healthy subjects. In clinical settings, the most reliable evaluation method for AO in patients with persistent idiopathic facial pain would be intraindividual assessments using HPT or mechanical allodynia tests. PMID:25627886

  17. Tongue weakness and somatosensory disturbance following oral endotracheal extubation.

    PubMed

    Su, Han; Hsiao, Tzu-Yu; Ku, Shih-Chi; Wang, Tyng-Guey; Lee, Jang-Jaer; Tzeng, Wen-Chii; Huang, Guan-Hua; Chen, Cheryl Chia-Hui

    2015-04-01

    The tongue plays important roles in mastication, swallowing, and speech, but its sensorimotor function might be affected by endotracheal intubation. The objective of this pilot study was to describe disturbances in the sensorimotor functions of the tongue over 14 days following oral endotracheal extubation. We examined 30 post-extubated patients who had prolonged (≥48 h) oral endotracheal intubation from six medical intensive care units. Another 36 patients were recruited and examined from dental and geriatric outpatient clinics served as a comparison group. Tongue strength was measured by the Iowa Oral Performance Instrument. Sensory disturbance of the tongue was measured by evaluating light touch sensation, oral stereognosis, and two-point discrimination with standardized protocols. Measurements were taken at three time points (within 48 h, and 7 and 14 days post-extubation) for patients with oral intubation but only once for the comparison group. The results show that independent of age, gender, tobacco used, and comorbidities, tongue strength was lower and its sensory functions were more impaired in patients who had oral intubation than in the comparison group. Sensory disturbances of the tongue gradually recovered, taking 14 days to be comparable with the comparison group, while weakness of the tongue persisted. In conclusion, patients with oral endotracheal intubation had weakness and somatosensory disturbances of the tongue lasting at least 14 days from extubation but whether is caused by intubation and whether is contributed to postextubation dysphagia should be further investigated.

  18. Fine-grained nociceptive maps in primary somatosensory cortex

    PubMed Central

    Mancini, Flavia; Haggard, Patrick; Iannetti, Gian Domenico; Longo, Matthew R.; Sereno, Martin I.

    2012-01-01

    Topographic maps of the receptive surface are a fundamental feature of neural organization in many sensory systems. While touch is finely mapped in the cerebral cortex, it remains controversial how precise any cortical nociceptive map may be. Given that nociceptive innervation density is relatively low on distal skin regions such as the digits, one might conclude that the nociceptive system lacks fine representation of these regions. Indeed, only gross spatial organization of nociceptive maps has been reported so far. However, here we reveal the existence of fine-grained somatotopy for nociceptive inputs to the digits in human primary somatosensory cortex (SI). Using painful nociceptive-selective laser stimuli to the hand, and phase-encoded fMRI analysis methods, we observed somatotopic maps of the digits in contralateral SI. These nociceptive maps were highly aligned with maps of non-painful tactile stimuli, suggesting comparable cortical representations for, and possible interactions between, mechanoreceptive and nociceptive signals. Our findings may also be valuable for future studies tracking the timecourse and the spatial pattern of plastic changes in cortical organization involved in chronic pain. PMID:23197708

  19. Spine loss in primary somatosensory cortex during trace eyeblink conditioning.

    PubMed

    Joachimsthaler, Bettina; Brugger, Dominik; Skodras, Angelos; Schwarz, Cornelius

    2015-03-01

    Classical conditioning that involves mnemonic processing, that is, a "trace" period between conditioned and unconditioned stimulus, requires awareness of the association to be formed and is considered a simple model paradigm for declarative learning. Barrel cortex, the whisker representation of primary somatosensory cortex, is required for the learning of a tactile variant of trace eyeblink conditioning (TTEBC) and undergoes distinct map plasticity during learning. To investigate the cellular mechanism underpinning TTEBC and concurrent map plasticity, we used two-photon imaging of dendritic spines in barrel cortex of awake mice while being conditioned. Monitoring layer 5 neurons' apical dendrites in layer 1, we show that one cellular expression of barrel cortex plasticity is a substantial spine count reduction of ∼15% of the dendritic spines present before learning. The number of eliminated spines and their time of elimination are tightly related to the learning success. Moreover, spine plasticity is highly specific for the principal barrel column receiving the main signals from the stimulated vibrissa. Spines located in other columns, even those directly adjacent to the principal column, are unaffected. Because layer 1 spines integrate signals from associative thalamocortical circuits, their column-specific elimination suggests that this spine plasticity may be the result of an association of top-down signals relevant for declarative learning and spatially precise ascending tactile signals.

  20. [Normative aspects of somatosensory evoked P300 components].

    PubMed

    Louzã Neto, M R; Maurer, K; Neuhauser, B

    1989-06-01

    Using a somatosensory version of the oddball-paradigma the influence of age and gender on the P300-component and the comparison of the potential after stimulation of the right and left median nerve was studied in 30 healthy right handed volunteers (age: 20-35 years). Latency, amplitude, area and duration of the P300-potential were analysed. No relationship between age, gender and the P300-parameters were observed. The amplitude and the area of the potential obtained from the F3 electrode were greater after stimulation of the right median nerve compared to the potential after stimulation of the left median nerve. All other results were not significantly different. Strong positive correlations between the results after stimulation of the right and left median nerve were observed. These results showed that by a young group of volunteers age and gender did not influence the P300-component. Although the P300-Parameters had a between-subject variability, their mean remained constant over the study, their correlation coefficients were strong positive and the side of stimulation did not influence them (except for the electrode F3). PMID:2547577

  1. Sharing social touch in the primary somatosensory cortex.

    PubMed

    Bolognini, Nadia; Rossetti, Angela; Fusaro, Martina; Vallar, Giuseppe; Miniussi, Carlo

    2014-07-01

    Touch has an emotional and communicative meaning, and it plays a crucial role in social perception and empathy. The intuitive link between others' somatosensations and our sense of touch becomes ostensible in mirror-touch synesthesia, a condition in which the view of a touch on another person's body elicits conscious tactile sensations on the observer's own body [1]. This peculiar phenomenon may implicate normal social mirror mechanisms [2]. Here, we show that mirror-touch interference effects, synesthesia-like sensations, and even phantom touches can be induced in nonsynesthetes by priming the primary somatosensory cortex (SI) directly or indirectly via the posterior parietal cortex. These results were obtained by means of facilitatory paired-pulse transcranial magnetic stimulation (ppTMS) contingent upon the observation of touch. For these vicarious effects, the SI is engaged at 150 ms from the onset of the visual touch. Intriguingly, individual differences in empathic abilities, assessed with the Interpersonal Reactivity Index [3], drive the activity of the SI when nonsynesthetes witness others' tactile sensations. This evidence implies that, under normal conditions, touch observation activates the SI below the threshold for perceptual awareness [4]; through the visual-dependent tuning of SI activity by ppTMS, what is seen becomes felt, namely, mirror-touch synesthesia. On a broader perspective, the visual responsivity of the SI may allow an automatic and unconscious transference of the sensation that another person is experiencing onto oneself, and, in turn, the empathic sharing of somatosensations [2]. PMID:24954046

  2. [Normative aspects of somatosensory evoked P300 components].

    PubMed

    Louzã Neto, M R; Maurer, K; Neuhauser, B

    1989-06-01

    Using a somatosensory version of the oddball-paradigma the influence of age and gender on the P300-component and the comparison of the potential after stimulation of the right and left median nerve was studied in 30 healthy right handed volunteers (age: 20-35 years). Latency, amplitude, area and duration of the P300-potential were analysed. No relationship between age, gender and the P300-parameters were observed. The amplitude and the area of the potential obtained from the F3 electrode were greater after stimulation of the right median nerve compared to the potential after stimulation of the left median nerve. All other results were not significantly different. Strong positive correlations between the results after stimulation of the right and left median nerve were observed. These results showed that by a young group of volunteers age and gender did not influence the P300-component. Although the P300-Parameters had a between-subject variability, their mean remained constant over the study, their correlation coefficients were strong positive and the side of stimulation did not influence them (except for the electrode F3).

  3. Prevalence of increases in functional connectivity in visual, somatosensory and language areas in congenital blindness

    PubMed Central

    Heine, Lizette; Bahri, Mohamed A.; Cavaliere, Carlo; Soddu, Andrea; Laureys, Steven; Ptito, Maurice; Kupers, Ron

    2015-01-01

    There is ample evidence that congenitally blind individuals rely more strongly on non-visual information compared to sighted controls when interacting with the outside world. Although brain imaging studies indicate that congenitally blind individuals recruit occipital areas when performing various non-visual and cognitive tasks, it remains unclear through which pathways this is accomplished. To address this question, we compared resting state functional connectivity in a group of congenital blind and matched sighted control subjects. We used a seed-based analysis with a priori specified regions-of-interest (ROIs) within visual, somato-sensory, auditory and language areas. Between-group comparisons revealed increased functional connectivity within both the ventral and the dorsal visual streams in blind participants, whereas connectivity between the two streams was reduced. In addition, our data revealed stronger functional connectivity in blind participants between the visual ROIs and areas implicated in language and tactile (Braille) processing such as the inferior frontal gyrus (Broca's area), thalamus, supramarginal gyrus and cerebellum. The observed group differences underscore the extent of the cross-modal reorganization in the brain and the supra-modal function of the occipital cortex in congenitally blind individuals. PMID:26190978

  4. Prevalence of increases in functional connectivity in visual, somatosensory and language areas in congenital blindness.

    PubMed

    Heine, Lizette; Bahri, Mohamed A; Cavaliere, Carlo; Soddu, Andrea; Laureys, Steven; Ptito, Maurice; Kupers, Ron

    2015-01-01

    There is ample evidence that congenitally blind individuals rely more strongly on non-visual information compared to sighted controls when interacting with the outside world. Although brain imaging studies indicate that congenitally blind individuals recruit occipital areas when performing various non-visual and cognitive tasks, it remains unclear through which pathways this is accomplished. To address this question, we compared resting state functional connectivity in a group of congenital blind and matched sighted control subjects. We used a seed-based analysis with a priori specified regions-of-interest (ROIs) within visual, somato-sensory, auditory and language areas. Between-group comparisons revealed increased functional connectivity within both the ventral and the dorsal visual streams in blind participants, whereas connectivity between the two streams was reduced. In addition, our data revealed stronger functional connectivity in blind participants between the visual ROIs and areas implicated in language and tactile (Braille) processing such as the inferior frontal gyrus (Broca's area), thalamus, supramarginal gyrus and cerebellum. The observed group differences underscore the extent of the cross-modal reorganization in the brain and the supra-modal function of the occipital cortex in congenitally blind individuals. PMID:26190978

  5. Motor Skill Acquisition and Retention after Somatosensory Electrical Stimulation in Healthy Humans

    PubMed Central

    Veldman, Menno P.; Zijdewind, Inge; Maffiuletti, Nicola A.; Hortobágyi, Tibor

    2016-01-01

    Somatosensory electrical stimulation (SES) can increase motor performance, presumably through a modulation of neuronal excitability. Because the effects of SES can outlast the period of stimulation, we examined the possibility that SES can also enhance the retention of motor performance, motor memory consolidation, after 24 h (Day 2) and 7 days (Day 7), that such effects would be scaled by SES duration, and that such effects were mediated by changes in aspects of corticospinal excitability, short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF). Healthy young adults (n = 40) received either 20 (SES-20), 40 (SES-40), or 60 min (SES-60) of real SES, or sham SES (SES-0). The results showed SES-20 increased visuomotor performance on Day 2 (15%) and Day 7 (17%) and SES-60 increased visuomotor performance on Day 7 (11%; all p < 0.05) compared with SES-0. Specific responses to transcranial magnetic stimulation (TMS) increased immediately after SES (p < 0.05) but not on Days 2 and 7. In addition, changes in behavioral and neurophysiological parameters did not correlate, suggesting that paths and structures other than the ones TMS can assay must be (also) involved in the increases in visuomotor performance after SES. As examined in the present study, low-intensity peripheral electrical nerve stimulation did not have acute effects on healthy adults' visuomotor performance but SES had delayed effects in the form of enhanced motor memory consolidation that were not scaled by the duration of SES. PMID:27014043

  6. Morphometric analysis of feedforward pathways from the primary somatosensory area (S1) of rats.

    PubMed

    Sá, A L de; Bahia, C P; Correa, V C; Dias, I A; Batista, C; Gomes-Leal, W; Pinho, A L S; Houzel, J C; Picanço-Diniz, C W; Pereira, A

    2016-01-01

    We used biotinylated dextran amine (BDA) to anterogradely label individual axons projecting from primary somatosensory cortex (S1) to four different cortical areas in rats. A major goal was to determine whether axon terminals in these target areas shared morphometric similarities based on the shape of individual terminal arbors and the density of two bouton types: en passant (Bp) and terminaux (Bt). Evidence from tridimensional reconstructions of isolated axon terminal fragments (n=111) did support a degree of morphological heterogeneity establishing two broad groups of axon terminals. Morphological parameters associated with the complexity of terminal arbors and the proportion of beaded Bp vs stalked Bt were found to differ significantly in these two groups following a discriminant function statistical analysis across axon fragments. Interestingly, both groups occurred in all four target areas, possibly consistent with a commonality of presynaptic processing of tactile information. These findings lay the ground for additional work aiming to investigate synaptic function at the single bouton level and see how this might be associated with emerging properties in postsynaptic targets. PMID:27191604

  7. [Variations in the configuration of somatosensory evoked potentials following stimulation of the median nerve].

    PubMed

    Strenge, H

    1989-09-01

    The variants of waveform patterns of cervical and cortical somatosensory evoked potentials to median nerve stimulation at the wrist were analysed in 86 normal subjects aged 15 to 71 years. In cervical SEP recordings the components N13, N14 and the trough-shaped variant of P17 showed the highest short-term stability. Immediate changes of the amplitude proportions of subcomponents within the potential, i.e. a lack of uniformity in waveforms, have to be considered normal. Significant associations were found between the occurrence of components N14 and an arm length of more than 68 cm and between the appearance of a plateau configuration of P17 and an age of at least 40 years. Considering definite criteria the latency of P17 can be used as an additional reliable parameter. In cortical SEP recordings the combination of an initial V-shaped pattern and a following bifid W-configuration appeared as the most frequent waveform profile. All parts of the potential but the positive waves of the primary complex revealed a high intraindividual stability. PMID:2507276

  8. Human Umbilical Cord Blood Cells Restore Brain Damage Induced Changes in Rat Somatosensory Cortex

    PubMed Central

    Geißler, Maren; Dinse, Hubert R.; Neuhoff, Sandra; Kreikemeier, Klaus; Meier, Carola

    2011-01-01

    Intraperitoneal transplantation of human umbilical cord blood (hUCB) cells has been shown to reduce sensorimotor deficits after hypoxic ischemic brain injury in neonatal rats. However, the neuronal correlate of the functional recovery and how such a treatment enforces plastic remodelling at the level of neural processing remains elusive. Here we show by in-vivo recordings that hUCB cells have the capability of ameliorating the injury-related impairment of neural processing in primary somatosensory cortex. Intact cortical processing depends on a delicate balance of inhibitory and excitatory transmission, which is disturbed after injury. We found that the dimensions of cortical maps and receptive fields, which are significantly altered after injury, were largely restored. Additionally, the lesion induced hyperexcitability was no longer observed in hUCB treated animals as indicated by a paired-pulse behaviour resembling that observed in control animals. The beneficial effects on cortical processing were reflected in an almost complete recovery of sensorimotor behaviour. Our results demonstrate that hUCB cells reinstall the way central neurons process information by normalizing inhibitory and excitatory processes. We propose that the intermediate level of cortical processing will become relevant as a new stage to investigate efficacy and mechanisms of cell therapy in the treatment of brain injury. PMID:21673795

  9. Thalamocortical Connections Drive Intracortical Activation of Functional Columns in the Mislaminated Reeler Somatosensory Cortex

    PubMed Central

    Wagener, Robin J.; Witte, Mirko; Guy, Julien; Mingo-Moreno, Nieves; Kügler, Sebastian; Staiger, Jochen F.

    2016-01-01

    Neuronal wiring is key to proper neural information processing. Tactile information from the rodent's whiskers reaches the cortex via distinct anatomical pathways. The lemniscal pathway relays whisking and touch information from the ventral posteromedial thalamic nucleus to layer IV of the primary somatosensory “barrel” cortex. The disorganized neocortex of the reeler mouse is a model system that should severely compromise the ingrowth of thalamocortical axons (TCAs) into the cortex. Moreover, it could disrupt intracortical wiring. We found that neuronal intermingling within the reeler barrel cortex substantially exceeded previous descriptions, leading to the loss of layers. However, viral tracing revealed that TCAs still specifically targeted transgenically labeled spiny layer IV neurons. Slice electrophysiology and optogenetics proved that these connections represent functional synapses. In addition, we assessed intracortical activation via immediate-early-gene expression resulting from a behavioral exploration task. The cellular composition of activated neuronal ensembles suggests extensive similarities in intracolumnar information processing in the wild-type and reeler brains. We conclude that extensive ectopic positioning of neuronal partners can be compensated for by cell-autonomous mechanisms that allow for the establishment of proper connectivity. Thus, genetic neuronal fate seems to be of greater importance for correct cortical wiring than radial neuronal position. PMID:26564256

  10. Individual Differences in Reward and Somatosensory-Motor Brain Regions Correlate with Adiposity in Adolescents.

    PubMed

    Rapuano, Kristina M; Huckins, Jeremy F; Sargent, James D; Heatherton, Todd F; Kelley, William M

    2016-06-01

    The prevalence of adolescent obesity has increased dramatically over the past three decades, and research has documented that the number of television shows viewed during childhood is associated with greater risk for obesity. In particular, considerable evidence suggests that exposure to food marketing promotes eating habits that contribute to obesity. The present study examines neural responses to dynamic food commercials in overweight and healthy-weight adolescents using functional magnetic resonance imaging (fMRI). Compared with non-food commercials, food commercials more strongly engaged regions involved in attention and saliency detection (occipital lobe, precuneus, superior temporal gyri, and right insula) and in processing rewards [left and right nucleus accumbens (NAcc) and left orbitofrontal cortex (OFC)]. Activity in the left OFC and right insula further correlated with subjects' percent body fat at the time of the scan. Interestingly, this reward-related activity to food commercials was accompanied by the additional recruitment of mouth-specific somatosensory-motor cortices-a finding that suggests the intriguing possibility that higher-adiposity adolescents mentally simulate eating behaviors and offers a potential neural mechanism for the formation and reinforcement of unhealthy eating habits that may hamper an individual's ability lose weight later in life. PMID:25994961

  11. Morphometric analysis of feedforward pathways from the primary somatosensory area (S1) of rats

    PubMed Central

    de Sá, A.L.; Bahia, C.P.; Correa, V.C.; Dias, I.A.; Batista, C.; Gomes-Leal, W.; Pinho, A.L.S.; Houzel, J.C.; Picanço-Diniz, C.W.; Pereira, A.

    2016-01-01

    We used biotinylated dextran amine (BDA) to anterogradely label individual axons projecting from primary somatosensory cortex (S1) to four different cortical areas in rats. A major goal was to determine whether axon terminals in these target areas shared morphometric similarities based on the shape of individual terminal arbors and the density of two bouton types: en passant (Bp) and terminaux (Bt). Evidence from tridimensional reconstructions of isolated axon terminal fragments (n=111) did support a degree of morphological heterogeneity establishing two broad groups of axon terminals. Morphological parameters associated with the complexity of terminal arbors and the proportion of beaded Bp vs stalked Bt were found to differ significantly in these two groups following a discriminant function statistical analysis across axon fragments. Interestingly, both groups occurred in all four target areas, possibly consistent with a commonality of presynaptic processing of tactile information. These findings lay the ground for additional work aiming to investigate synaptic function at the single bouton level and see how this might be associated with emerging properties in postsynaptic targets. PMID:27191604

  12. Types of Contact Lenses

    MedlinePlus

    ... Consumer Devices Consumer Products Contact Lenses Types of Contact Lenses Share Tweet Linkedin Pin it More sharing ... Orthokeratology (Ortho-K) Decorative (Plano) Contact Lenses Soft Contact Lenses Soft contact lenses are made of soft, ...

  13. fMRI investigation of unexpected somatosensory feedback perturbation during speech

    PubMed Central

    Golfinopoulos, Elisa; Tourville, Jason A.; Bohland, Jason W.; Ghosh, Satrajit S.; Nieto-Castanon, Alfonso; Guenther, Frank H.

    2011-01-01

    Somatosensory feedback plays a critical role in the coordination of articulator movements for speech production. In response to unexpected resistance to lip or jaw movements during speech, fluent speakers can use the difference between the somatosensory expectations of a speech sound and the actual somatosensory feedback to adjust the trajectories of functionally relevant but unimpeded articulators. In an effort to investigate the neural substrates underlying the somatosensory feedback control of speech, we used an event-related sparse sampling functional magnetic resonance imaging paradigm and a novel pneumatic device that unpredictably blocked subjects’ jaw movements. In comparison to speech, perturbed speech, in which jaw perturbation prompted the generation of compensatory speech motor commands, demonstrated increased effects in bilateral ventral motor cortex, right-lateralized anterior supramarginal gyrus, inferior frontal gyrus pars triangularis and ventral premotor cortex, and bilateral inferior posterior cerebellum (lobule VIII). Structural equation modeling revealed a significant increased influence from left anterior supramarginal gyrus to right anterior supramarginal gyrus and from left anterior supramarginal gyrus to right ventral premotor cortex as well as a significant increased reciprocal influence between right ventral premotor cortex and right ventral motor cortex and right anterior supramarginal gyrus and right inferior frontal gyrus pars triangularis for perturbed speech relative to speech. These results suggest that bilateral anterior supramarginal gyrus, right inferior frontal gyrus pars triangularis, right ventral premotor and motor cortices are functionally coupled and influence speech motor output when somatosensory feedback is unexpectedly perturbed during speech production. PMID:21195191

  14. Architectonic mapping of somatosensory areas involved in skilled forelimb movements and tool use.

    PubMed

    Mayer, Andrei; Nascimento-Silva, Márcio L; Keher, Natalia B; Bittencourt-Navarrete, Ruben Ernesto; Gattass, Ricardo; Franca, João G

    2016-05-01

    Cebus monkeys stand out from other New World monkeys by their ability to perform fine hand movements, and by their spontaneous use of tools in the wild. Those behaviors rely on the integration of somatosensory information, which occurs in different areas of the parietal cortex. Although a few studies have examined and parceled the somatosensory areas of the cebus monkey, mainly using electrophysiological criteria, very little is known about its anatomical organization. In this study we used SMI-32 immunohistochemistry, myelin, and Nissl stains to characterize the architecture of the parietal cortical areas of cebus monkeys. Seven cortical areas were identified between the precentral gyrus and the anterior bank of the intraparietal sulcus. Except for areas 3a and 3b, distinction between different somatosensory areas was more evident in myelin-stained sections and SMI-32 immunohistochemistry than in Nissl stain, especially for area 2 and subdivisions of area 5. Our results show that cebus monkeys have a relatively complex somatosensory cortex, similar to that of macaques and humans. This suggests that, during primate evolution, the emergence of new somatosensory areas underpinned complex manual behaviors in most Old World simians and in the New World cebus monkey. J. Comp. Neurol. 524:1399-1423, 2016. © 2015 Wiley Periodicals, Inc.

  15. Integrated approach for studying adaptation mechanisms in the human somatosensory cortical network.

    PubMed

    Venkatesan, Lalit; Barlow, Steven M; Popescu, Mihai; Popescu, Anda

    2014-11-01

    Magnetoencephalography and independent component analysis (ICA) was utilized to study and characterize neural adaptation in the somatosensory cortical network. Repetitive punctate tactile stimuli were applied unilaterally to the dominant hand and face using a custom-built pneumatic stimulator called the TAC-Cell. ICA-based source estimation from the evoked neuromagnetic responses indicated cortical activity in the contralateral primary somatosensory cortex (SI) for face stimulation, while hand stimulation resulted in robust contralateral SI and posterior parietal cortex (PPC) activation. Activity was also observed in the secondary somatosensory cortical area (SII) with reduced amplitude and higher variability across subjects. There was a significant difference in adaptation rate between SI and higher-order somatosensory cortices for hand stimulation. Adaptation was significantly dependent on stimulus frequency and pulse index within the stimulus train for both hand and face stimulation. The peak latency of the activity was significantly dependent on stimulation site (hand vs. face) and cortical area (SI vs. PPC). The difference in the peak latency of activity in SI and PPC is presumed to reflect a hierarchical serial-processing mechanism in the somatosensory cortex.

  16. Reliability of Visual and Somatosensory Feedback in Skilled Movement: The Role of the Cerebellum.

    PubMed

    Mizelle, J C; Oparah, Alexis; Wheaton, Lewis A

    2016-01-01

    The integration of vision and somatosensation is required to allow for accurate motor behavior. While both sensory systems contribute to an understanding of the state of the body through continuous updating and estimation, how the brain processes unreliable sensory information remains to be fully understood in the context of complex action. Using functional brain imaging, we sought to understand the role of the cerebellum in weighting visual and somatosensory feedback by selectively reducing the reliability of each sense individually during a tool use task. We broadly hypothesized upregulated activation of the sensorimotor and cerebellar areas during movement with reduced visual reliability, and upregulated activation of occipital brain areas during movement with reduced somatosensory reliability. As specifically compared to reduced somatosensory reliability, we expected greater activations of ipsilateral sensorimotor cerebellum for intact visual and somatosensory reliability. Further, we expected that ipsilateral posterior cognitive cerebellum would be affected with reduced visual reliability. We observed that reduced visual reliability results in a trend towards the relative consolidation of sensorimotor activation and an expansion of cerebellar activation. In contrast, reduced somatosensory reliability was characterized by the absence of cerebellar activations and a trend towards the increase of right frontal, left parietofrontal activation, and temporo-occipital areas. Our findings highlight the role of the cerebellum for specific aspects of skillful motor performance. This has relevance to understanding basic aspects of brain functions underlying sensorimotor integration, and provides a greater understanding of cerebellar function in tool use motor control.

  17. Functional magnetic resonance imaging connectivity analyses reveal efference-copy to primary somatosensory area, BA2.

    PubMed

    Cui, Fang; Arnstein, Dan; Thomas, Rajat Mani; Maurits, Natasha M; Keysers, Christian; Gazzola, Valeria

    2014-01-01

    Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively. We found electromyographical recordings, an efference-copy proxy, to predict activity in primary somatosensory regions, in particular Brodmann Area (BA) 2. Partial correlation analyses confirmed that brain activity in cortical structures associated with motor control (premotor and supplementary motor cortices, the parietal area PF and the cerebellum) predicts brain activity in BA2 without being entirely mediated by activity in early somatosensory (BA3b) cortex. Our study therefore provides valuable empirical evidence for efference-copy models of motor control, and shows that signals in BA2 can indeed reflect an input from motor cortices and suggests that we should interpret activations in BA2 as evidence for somatosensory-motor rather than somatosensory coding alone.

  18. Functional Magnetic Resonance Imaging Connectivity Analyses Reveal Efference-Copy to Primary Somatosensory Area, BA2

    PubMed Central

    Cui, Fang; Arnstein, Dan; Thomas, Rajat Mani; Maurits, Natasha M.; Keysers, Christian; Gazzola, Valeria

    2014-01-01

    Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively. We found electromyographical recordings, an efference-copy proxy, to predict activity in primary somatosensory regions, in particular Brodmann Area (BA) 2. Partial correlation analyses confirmed that brain activity in cortical structures associated with motor control (premotor and supplementary motor cortices, the parietal area PF and the cerebellum) predicts brain activity in BA2 without being entirely mediated by activity in early somatosensory (BA3b) cortex. Our study therefore provides valuable empirical evidence for efference-copy models of motor control, and shows that signals in BA2 can indeed reflect an input from motor cortices and suggests that we should interpret activations in BA2 as evidence for somatosensory-motor rather than somatosensory coding alone. PMID:24416222

  19. Interhemispheric connections of the somatosensory cortex in the rabbit.

    PubMed

    Ledoux, M S; Whitworth, R H; Gould, H J

    1987-04-01

    Corpus callosal connections of somatosensory cortex were studied in rabbits by combining anatomical tracing and electrophysiological mapping in the same animals. The results show that callosal connections are unevenly distributed in SI and SII. In SI, the representations of all body surfaces caudal to the neck and midline structures of the head have dense callosal connections. Conversely, connections are sparse to absent within representations of laterally positioned surfaces of the head, such as the sinus hairs, vibrissae, and nonmidline portions of the lips. Almost all of SII has dense callosal connections; only the representations of the vibrissae and sinus hairs have moderate callosal connections. The laminar distribution of callosal connections in rabbit SI and SII is similar to that observed in other mammals. Callosal terminations extend from the inner portion of layer I to the outer portion of layer VI, are moderately denser in the supragranular layers, and are sparse in layer IV. Callosally projecting cells are found predominantly in layers II, III, and V and are sparse in layers IV and VI. These data further emphasize the direct correspondence between the pattern of callosal connections in SI and the functional importance of particular body surfaces. Hence, representations of body surfaces important in the exploration of the environment are relatively free of callosal connections, whereas representations of midline and more lateral surfaces, less significant in tactile exploration, receive dense callosal connections. Callosal connections in rabbits are distributed extensively throughout responsive koniocortical regions rather than being relegated to distinct, specialized regions of "unresponsive" dysgranular cortex as in rodents.

  20. [Clinical application of the central somatosensory conduction time (CCT)].

    PubMed

    Ueda, M; Matsumae, M; Sato, O; Suzuki, Y; Murase, H; Sakurai, I

    1987-09-01

    We tried to prove the usefulness of CCT as an index of cerebral functions. CCT, regional cerebral blood flow (CBF) and CT scan findings were studied in 213 neurological patients with CVD (66 cases), cerebral tumors (66 cases) and head traumas (81 cases). The technique of CCT recording was modified from that of Jones (1977) using CADWELL 5200 system. CCT was defined as the difference of the peak latency between N13 recorded at the C-7 vertebral electrode and N20 recorded at the somatosensory cortex. The control CCT in normal volunteers (N = 20) was 5.7 +/- 0.4 msec. RCBF was measured with 133 Xe intra carotid injection method of Lassen & Ingvar using gammacamera (DEC GAMM 11/34). CCT tended significantly to become more prolonged in affected hemisphere than in unaffected hemisphere of patients with three groups (CVD, tumor and trauma) (p less than 0.01). Forty percent reduction of control rCBF caused a prolongation of CCT over 7 msec. The degrees of CCT prolongations appeared to be proportional to the degree of rCBF diminution. Prolongation of CCT was remarkable in the side of low density area on CT scan. The prolongation of CCT were revealed in the patients before they did not manifest their neurological deficits especially in the disease of metastatic tumors and glioma. In the case of patients with trauma who we could follow to measure rCBF, CCT tended to become shorten as rCBF increased till normal range. CCT was not significantly prolonged in congenital hydrocephalus.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Using constellation pharmacology to define comprehensively a somatosensory neuronal subclass.

    PubMed

    Teichert, Russell W; Memon, Tosifa; Aman, Joseph W; Olivera, Baldomero M

    2014-02-11

    Change is intrinsic to nervous systems; change is required for learning and conditioning and occurs with disease progression, normal development, and aging. To better understand mammalian nervous systems and effectively treat nervous-system disorders, it is essential to track changes in relevant individual neurons. A critical challenge is to identify and characterize the specific cell types involved and the molecular-level changes that occur in each. Using an experimental strategy called constellation pharmacology, we demonstrate that we can define a specific somatosensory neuronal subclass, cold thermosensors, across different species and track changes in these neurons as a function of development. Cold thermosensors are uniformly responsive to menthol and innocuous cool temperature (17 °C), indicating that they express TRPM8 channels. A subset of cold thermosensors expressed α7 nicotinic acetylcholine receptors (nAChRs) but not other nAChR subtypes. Differences in temperature threshold of cold thermosensors correlated with functional expression of voltage-gated K channels Kv1.1/1.2: Relatively higher expression of KV1.1/1.2 channels resulted in a higher threshold response to cold temperature. Other signaling components varied during development and between species. In cold thermosensors of neonatal mice and rats, ATP receptors were functionally expressed, but the expression disappeared with development. This developmental change occurred earlier in low-threshold than high-threshold cold thermosensors. Most rat cold thermosensors expressed TRPA1 channels, whereas mouse cold thermosensors did not. The broad implications of this study are that it is now feasible to track changes in receptor and ion-channel expression in individual neuronal subclasses as a function of development, learning, disease, or aging.

  2. Sensitivity to microstimulation of somatosensory cortex distributed over multiple electrodes.

    PubMed

    Kim, Sungshin; Callier, Thierri; Tabot, Gregg A; Tenore, Francesco V; Bensmaia, Sliman J

    2015-01-01

    Meaningful and repeatable tactile sensations can be evoked by electrically stimulating primary somatosensory cortex. Intracortical microstimulation (ICMS) may thus be a viable approach to restore the sense of touch in individuals who have lost it, for example tetraplegic patients. One of the potential limitations of this approach, however, is that high levels of current can damage the neuronal tissue if the resulting current densities are too high. The limited range of safe ICMS amplitudes thus limits the dynamic range of ICMS-evoked sensations. One way to get around this limitation would be to distribute the ICMS over multiple electrodes in the hopes of intensifying the resulting percept without increasing the current density experienced by the neuronal tissue. Here, we test whether stimulating through multiple electrodes is a viable solution to increase the dynamic range of ICMS-elicited sensations without increasing the peak current density. To this end, we compare the ability of non-human primates to detect ICMS delivered through one vs. multiple electrodes. We also compare their ability to discriminate pulse trains differing in amplitude when these are delivered through one or more electrodes. We find that increasing the number of electrodes through which ICMS is delivered only has a marginal effect on detectability or discriminability despite the fact that 2-4 times more current is delivered overall. Furthermore, the impact of multielectrode stimulation (or lack thereof) is found whether pulses are delivered synchronously or asynchronously, whether the leading phase of the pulses is cathodic or anodic, and regardless of the spatial configuration of the electrode groups. PMID:25914630

  3. Evaluation of somatosensory cortical differences between flutter and vibration tactile stimuli.

    PubMed

    Han, Sang Woo; Chung, Yoon Gi; Kim, Hyung-Sik; Chung, Soon-Cheol; Park, Jang-Yeon; Kim, Sung-Phil

    2013-01-01

    In parallel with advances in haptic-based mobile computing systems, understanding of the neural processing of vibrotactile information becomes of great importance. In the human nervous system, two types of vibrotactile information, flutter and vibration, are delivered from mechanoreceptors to the somatosensory cortex through segregated neural afferents. To investigate how the somatosensory cortex differentiates flutter and vibration, we analyzed the cortical responses to vibrotactile stimuli with a wide range of frequencies. Specifically, we examined whether cortical activity changed most around 50 Hz, which is known as a boundary between flutter and vibration. We explored various measures to evaluate separability of cortical activity across frequency and found that the hypothesis margin method resulted in the greatest separability between flutter and vibration. This result suggests that flutter and vibration information may be processed by different neural processes in the somatosensory cortex.

  4. [Tactile agnosia and dysfunction of the primary somatosensory area. Data of the study by somatosensory evoked potentials in patients with deficits of tactile object recognition].

    PubMed

    Mauguière, F; Isnard, J

    1995-01-01

    The question as to whether a failure of recognition unrelated to impaired sensory processing or to disorder of naming can occur in the somato-sensory modality has been eagerly debated in the french neurology. Taking as an argument the fact that he had never observed a tactile agnosia in the absence of subtle sensory deficits Dejerine denied the localizing value of tactile agnosia (or asterognosis). Conversely Delay, 20 years later, identified tactile performances such as discrimination of texture and shapes, which he considered as a specific neocortical function, that were lost in parietal syndromes with astereognosis and preserved elementary sensations. He also coined the term "tactile asymbolia" to qualify the patients with astereognosis in whom these performances are preserved. When referring to the definition of agnosias only "tactile asymbolia" should be considered as a "true" tactile agnosia. The recording of early somatosensory evoked potentials (SEPs) now offers the possibility of assessing non invasively the function of the primary somatosensory cortex (in particular area 3b). We have recorded SEPs to median nerve or finger stimulation in 309 subjects with a focal hemispheric lesion presenting with a somatosensory deficit of any type. We could confirm that asterognosis referable to impaired discrimination of textures and/or shapes in the absence of impaired elementary sensation is quite rare since it was observed in only 12 of our patients (3.9%). Moreover early cortical SEPs reflecting the activity of the primary somatosensory area (N20 or/and P27) were clearly abnormal in all of them. A single patient of this group of 12 could be considered as a case of tactile asymbolia but his early cortical SEPs were abnormal. The only condition combining a failure of tactile recognition of objects with normal early SEPs is represented by the "tactile anomia" observed in callosal dysconnexions. Thus, in our patients unable to identify objects by palpation in spite of

  5. Short-Latency Median-Nerve Somatosensory-Evoked Potentials and Induced Gamma-Oscillations in Humans

    ERIC Educational Resources Information Center

    Fukuda, Miho; Nishida, Masaaki; Juhasz, Csaba; Muzik, Otto; Sood, Sandeep; Chugani, Harry T.; Asano, Eishi

    2008-01-01

    Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the…

  6. Forebrain organization representing baroreceptor gating of somatosensory afferents within the cortical autonomic network.

    PubMed

    Goswami, Ruma; Frances, Maria Fernanda; Steinback, Craig Douglas; Shoemaker, J Kevin

    2012-07-01

    Somatosensory afferents are represented within the cortical autonomic network (CAN). However, the representation of somatosensory afferents, and the consequent cardiovascular effects, may be modified by levels of baroreceptor input. Thus, we examined the cortical regions involved with processing somatosensory inputs during baroreceptor unloading. Neuroimaging sessions (functional magnetic resonance imaging [fMRI]) recorded brain activity during 30 mmHg lower-body negative pressure (LBNP) alone and combined with somatosensory stimulation (LBNP+SS) of the forearm (n = 14). Somatosensory processing was also assessed during increased sympathetic outflow via end-expiratory apnea. Heart rate (HR), blood pressure (BP), cardiac output (Q), and muscle sympathetic nerve activity (MSNA) were recorded during the same protocols in a separate laboratory session. SS alone had no effect on any cardiovascular or MSNA variable at rest. Measures of HR, BP, and Q during LBNP were not different compared with LBNP+SS. The rise in MSNA burst frequency was attenuated during LBNP+SS versus LBNP alone (8 vs. 12 bursts/min, respectively, P < 0.05). SS did not affect the change in MSNA during apnea. Activations within the insula and dorsal anterior cingulate cortex (ACC) observed during LBNP were not seen during LBNP+SS. Anterior insula and ACC activations occurring during apnea were not modified by SS. Thus, the absence of insular and dorsal ACC activity during LBNP+SS along with an attenuation of MSNA burst frequency suggest sympathoinhibitory effects of sensory stimulation during decreased baroreceptor input by a mechanism that includes conjoint insula-dorsal ACC regulation. These findings reveal that the level of baroreceptor input influences the forebrain organization of somatosensory afferents. PMID:22514285

  7. Reducing contact resistance in graphene devices through contact area patterning.

    PubMed

    Smith, Joshua T; Franklin, Aaron D; Farmer, Damon B; Dimitrakopoulos, Christos D

    2013-04-23

    Performance of graphene electronics is limited by contact resistance associated with the metal-graphene (M-G) interface, where unique transport challenges arise as carriers are injected from a 3D metal into a 2D-graphene sheet. In this work, enhanced carrier injection is experimentally achieved in graphene devices by forming cuts in the graphene within the contact regions. These cuts are oriented normal to the channel and facilitate bonding between the contact metal and carbon atoms at the graphene cut edges, reproducibly maximizing "edge-contacted" injection. Despite the reduction in M-G contact area caused by these cuts, we find that a 32% reduction in contact resistance results in Cu-contacted, two-terminal devices, while a 22% reduction is achieved for top-gated graphene transistors with Pd contacts as compared to conventionally fabricated devices. The crucial role of contact annealing to facilitate this improvement is also elucidated. This simple approach provides a reliable and reproducible means of lowering contact resistance in graphene devices to bolster performance. Importantly, this enhancement requires no additional processing steps.

  8. Mild systemic inflammation and moderate hypoxia transiently alter neuronal excitability in mouse somatosensory cortex.

    PubMed

    Mordel, Jérôme; Sheikh, Aminah; Tsohataridis, Simeon; Kanold, Patrick O; Zehendner, Christoph M; Luhmann, Heiko J

    2016-04-01

    During the perinatal period, the brain is highly vulnerable to hypoxia and inflammation, which often cause white matter injury and long-term neuronal dysfunction such as motor and cognitive deficits or epileptic seizures. We studied the effects of moderate hypoxia (HYPO), mild systemic inflammation (INFL), or the combination of both (HYPO+INFL) in mouse somatosensory cortex induced during the first postnatal week on network activity and compared it to activity in SHAM control animals. By performing in vitro electrophysiological recordings with multi-electrode arrays from slices prepared directly after injury (P8-10), one week after injury (P13-16), or in young adults (P28-30), we investigated how the neocortical network developed following these insults. No significant difference was observed between the four groups in an extracellular solution close to physiological conditions. In extracellular 8mM potassium solution, slices from the HYPO, INFL, and HYPO+INFL group were more excitable than SHAM at P8-10 and P13-16. In these two age groups, the number and frequency of spontaneous epileptiform events were significantly increased compared to SHAM. The frequency of epileptiform events was significantly reduced by the NMDA antagonist D-APV in HYPO, INFL, and HYPO+INFL, but not in SHAM, indicating a contribution of NMDA receptors to this pathophysiological activity. In addition, the AMPA/kainate receptor antagonist CNQX suppressed the remaining epileptiform activity. Electrical stimulation evoked prominent epileptiform activity in slices from HYPO, INFL and HYPO+INFL animals. Stimulation threshold to elicit epileptiform events was lower in these groups than in SHAM. Evoked events spread over larger areas and lasted longer in treated animals than in SHAM. In addition, the evoked epileptiform activity was reduced in the older (P28-30) group indicating that cortical dysfunction induced by hypoxia and inflammation was transient and compensated during early development.

  9. Cortical and medullary somatosensory projections to the cochlear nuclear complex in the hedgehog tenrec.

    PubMed

    Wolff, A; Künzle, H

    1997-01-17

    Various tracer substances were injected into the spinal cord, the dorsal column nuclei, the trigeminal nuclear complex and the somatosensory cortex in Madagascan hedgehog tenrecs. With the exception of the cases injected exclusively into the spinal cord all injections gave rise to sparse, but distinct anterograde projections to the cochlear nuclear complex, particularly the granular cell domain within and outside of the dorsal cochlear nucleus. Among these cochlear afferents the projection from the primary somatosensory cortex is the most remarkable because the hedgehog tenrec has one of the lowest encephalisation indices among mammals and a similar cortico-cochlear connection has not been demonstrated so far in other species.

  10. Role of somatosensory and vestibular cues in attenuating visually induced human postural sway

    NASA Technical Reports Server (NTRS)

    Peterka, Robert J.; Benolken, Martha S.

    1993-01-01

    The purpose was to determine the contribution of visual, vestibular, and somatosensory cues to the maintenance of stance in humans. Postural sway was induced by full field, sinusoidal visual surround rotations about an axis at the level of the ankle joints. The influences of vestibular and somatosensory cues were characterized by comparing postural sway in normal and bilateral vestibular absent subjects in conditions that provided either accurate or inaccurate somatosensory orientation information. In normal subjects, the amplitude of visually induced sway reached a saturation level as stimulus amplitude increased. The saturation amplitude decreased with increasing stimulus frequency. No saturation phenomena was observed in subjects with vestibular loss, implying that vestibular cues were responsible for the saturation phenomenon. For visually induced sways below the saturation level, the stimulus-response curves for both normal and vestibular loss subjects were nearly identical implying that (1) normal subjects were not using vestibular information to attenuate their visually induced sway, possibly because sway was below a vestibular-related threshold level, and (2) vestibular loss subjects did not utilize visual cues to a greater extent than normal subjects; that is, a fundamental change in visual system 'gain' was not used to compensate for a vestibular deficit. An unexpected finding was that the amplitude of body sway induced by visual surround motion could be almost three times greater than the amplitude of the visual stimulus in normals and vestibular loss subjects. This occurred in conditions where somatosensory cues were inaccurate and at low stimulus amplitudes. A control system model of visually induced postural sway was developed to explain this finding. For both subject groups, the amplitude of visually induced sway was smaller by a factor of about four in tests where somatosensory cues provided accurate versus inaccurate orientation information. This

  11. Chain Of Test Contacts For Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Lieneweg, Udo

    1989-01-01

    Test structure forms chain of "cross" contacts fabricated together with large-scale integrated circuits. If necessary, number of such chains incorporated at suitable locations in integrated-circuit wafer for determination of fabrication yield of contacts. In new structure, resistances of individual contacts determined: In addition to making it possible to identify local defects, enables generation of statistical distributions of contact resistances for prediction of "parametric" contact yield of fabrication process.

  12. Representation of somatosensory inputs within the cortical autonomic network.

    PubMed

    Goswami, Ruma; Frances, Maria Fernanda; Shoemaker, J Kevin

    2011-01-15

    Regions of the cortical autonomic network (CAN) are activated during muscle contraction. However, it is not known to what extent CAN activation patterns reflect muscle sensory inputs, top-down signals from the motor cortex, and/or motor drive to cardiovascular structures. The present study explored the functional representation of somatosensory afferent input within the CAN with an a priori interest in the insula and ventral medial prefrontal cortex (vMPFC) (n=12). Heart rate (HR) and functional MRI data were acquired during 1) 30s periods of electrical stimulation of the wrist flexors at sub-motor (SUB; Type I,II afferents) and 2) motor thresholds (MOT; Type I,II,III afferents), 3) volitional wrist flexion at 5% maximal voluntary contraction (MVC) to match the MOT tension (VOL5%), and 4) volitional handgrip at 35% MVC to elicit tachycardia (VOL35%). Compared with rest, HR did not change during SUB, MOT, or VOL5% but increased during VOL35% (p<0.001). High frequency HR variability was 29.42±18.87 ms(2) (mean±S.D.) at rest and 39.85±27.60 ms(2) during SUB (p=0.06). High frequency HR variability was decreased during VOL35% compared to rest (p≤0.005). SUB increased activity in the bilateral posterior insula, vMPFC, subgenual anterior cingulate cortex (ACC), mid-cingulate cortex (MCC), and posterior cingulate cortex. MOT increased activity in the left posterior insula and MCC. During VOL5%, activity increased in the right anterior-mid insula. VOL35% was associated with activity in the bilateral insula as well as vMPFC and subgenual ACC deactivation. These data suggest that the left posterior insula processes sensory input from muscle during passive conditions and specifically that Type I and/or II muscle afferent stimulation during SUB impacts the vMPFC and/or subgenual ACC, regions believed to be involved in brain default mode and parasympathetic activity. PMID:20884359

  13. Contact pressure-aided spectroscopy.

    PubMed

    Bregar, Maksimilijan; Bürmen, Miran; Aljancic, Uroš; Cugmas, Blaž; Pernuš, Franjo; Likar, Boštjan

    2014-02-01

    Contact pressure induced by manually operated fiber optic probes can significantly affect the optical properties of the studied tissue. If the contact pressure and the changes in optical properties are measured properly, then the complementary information can be used to obtain additional insight into the tissue physiology. However, as reliable assessment of the contact pressure in the existing diffuse reflectance setups is difficult, the impact of contact pressure is usually neglected or considered as a source of errors. We introduce a measurement system for controlled application of contact pressure and for the acquisition of diffuse reflectance spectra, which is suitable for in vivo studies and for overcoming the limitations of the existing measurement setups. A spectral-contact-pressure plane is proposed to present the combined information, highlighting the unique tissue response to the applied pressure.

  14. Contact dermatitis in children.

    PubMed

    Rademaker, M; Forsyth, A

    1989-02-01

    125 children under the age of 12 years were patch tested over a period of 7 years. 60 (48%) of the children had 1 or more positive (+ve) reactions, of which 92% (55/60) were considered relevant. The most common allergens were metals (35 + ves), fragrances (24 + ves) and rubber compounds (11 + ves). 40 of the children were also tested for contact urticaria against food additives and fragrances, of whom 20 were positive (benzoic acid 14, cinnamaldehyde 12).

  15. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

    PubMed

    Castejon, Carlos; Barros-Zulaica, Natali; Nuñez, Angel

    2016-01-01

    Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm) is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1) in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas.

  16. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function

    PubMed Central

    Castejon, Carlos; Barros-Zulaica, Natali; Nuñez, Angel

    2016-01-01

    Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm) is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1) in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas. PMID:26820514

  17. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

    PubMed

    Castejon, Carlos; Barros-Zulaica, Natali; Nuñez, Angel

    2016-01-01

    Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm) is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1) in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas. PMID:26820514

  18. EDITORIAL: Close contact Close contact

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2010-07-01

    The development of scanning probe techniques, such as scanning tunnelling microscopy [1], has often been touted as the catalyst for the surge in activity and progress in nanoscale science and technology. Images of nanoscale structural detail have served as an invaluable investigative resource and continue to fascinate with the fantastical reality of an intricate nether world existing all around us, but hidden from view of the naked eye by a disparity in scale. As is so often the case, the invention of the scanning tunnelling microscope heralded far more than just a useful new apparatus, it demonstrated the scope for exploiting the subtleties of electronic contact. The shrinking of electronic devices has been a driving force for research into molecular electronics, in which an understanding of the nature of electronic contact at junctions is crucial. In response, the number of experimental techniques in molecular electronics has increased rapidly in recent years. Scanning tunnelling microscopes have been used to study electron transfer through molecular films on a conducting substrate, and the need to monitor the contact force of scanning tunnelling electrodes led to the use of atomic force microscopy probes coated in a conducting layer as studied by Cui and colleagues in Arizona [2]. In this issue a collaboration of researchers at Delft University and Leiden University in the Netherlands report a new device architecture for the independent mechanical and electrostatic tuning of nanoscale charge transport, which will enable thorough studies of molecular transport in the future [3]. Scanning probes can also be used to pattern surfaces, such as through spatially-localized Suzuki and Heck reactions in chemical scanning probe lithography. Mechanistic aspects of spatially confined Suzuki and Heck chemistry are also reported in this issue by researchers in Oxford [4]. All these developments in molecular electronics fabrication and characterization provide alternative

  19. Somatosensory evoked potentials assess the efficacy of circumcision for premature ejaculation.

    PubMed

    Xia, J-D; Jiang, H-S; Zhu, L-L; Zhang, Z; Chen, H; Dai, Y-T

    2016-07-01

    To assess the efficacy and mechanism of circumcision in the treatment of premature ejaculation (PE) with redundant prepuce, we enrolled a total of 81 PE patients who received circumcision. The patients' ejaculatory ability and sexual performances were evaluated before and after circumcision by using questionnaires (Intravaginal ejaculation latency time (IELT), Chinese Index of PE with 5 questions (CIPE-5) and International Index of Erectile function- 5 (IIEF-5)). Furthermore, somatosensory evoked potentials (SEPs) including dorsal nerve (DNSEP) and glans penis (GPSEP) of the patients were also measured. The mean IELTs of preoperation and post operation were 1.10±0.55 and 2.48±2.03 min, respectively (P<0.001). In addition, the geometric mean IELT after operation was 2.16 min, compared with the baseline 1.07 min before the operation, the fold increase of the IELT was 2.02. Compared with the uncircumcised status, scores of CIPE-5 showed a significant increase after circumcision (P<0.001). The mean latencies (and amplitudes) of GPSEP and DNSEP were 38.1±4.0 ms (3.0±1.9 uV) and 40.5±3.4 ms (2.8±1.6 uV) before circumcision, respectively; and 42.8±3.3 ms (2.8±1.6 uV) and 40.5±4.1 ms (2.4±1.2 uV) in the follow-up end point after circumcision. Only the latencies of GPSEP showed significant prolongation before and after circumcision (P<0.001). The ejaculation time improvement after circumcision is so small, and equal to placebo response, therefore it could not be interpreted as a therapeutic method in men with PE.

  20. Effects of flurbiprofen enantiomers on pain-related chemo-somatosensory evoked potentials in human subjects.

    PubMed Central

    Lötsch, J; Geisslinger, G; Mohammadian, P; Brune, K; Kobal, G

    1995-01-01

    1. The aim of the study was to investigate the analgesic effects of flurbiprofen enantiomers using an experimental pain model based on both chemo-somatosensory event-related potentials (CSSERP) and subjective pain ratings. 2. Healthy female volunteers (n = 16, age 23-36 years) participated in a placebo-controlled, randomised, double-blind, four-way crossover study. Single doses of (S)-flurbiprofen (50 mg), (R)-flurbiprofen (50 and 100 mg) and placebo were administered orally. Measurements were taken before and 2 h after administration of the medications. During each measurement, 32 painful stimuli of gaseous carbon dioxide (200 ms duration, interval approximately 30 s) of two concentrations (60 and 65% CO2 v/v) were applied to the right nostril. EEG was recorded from five positions and CSSERP were obtained in response to the painful CO2- stimuli. Additionally, subjects rated the perceived intensity of the painful stimuli by means of a visual analogue scale (VAS). 3. The CSSERP-amplitude P2, a measure of analgesic effect, decreased after administration of both (R)- and (S)-flurbiprofen, while it increased after placebo. This was statistically significant at recording positions C4 (P < 0.01) and Fz (P < 0.05). The analgesia-related decreases in evoked potential produced by (R)-flurbiprofen were dose-dependent. Comparing similar doses of (R)- and (S)-flurbiprofen, the decrease in CSSERP-amplitudes produced by the (S)-enantiomer was somewhat more pronounced, indicating a higher analgesic potency. 4. The present data indicate that both enantiomers of flurbiprofen produce analgesic effects. Since (R)-flurbiprofen caused only little toxicity in rats as compared with the (S)-enantiomer or the racemic compound, a reduction of the quantitatively most important side effects in the gastrointestinal tract might be achieved by employing (R)-flurbiprofen in pain therapy. PMID:8554936

  1. Distribution and morphology of nitrergic neurons across functional domains of the rat primary somatosensory cortex

    PubMed Central

    Nogueira-Campos, Anaelli A.; Finamore, Deborah M.; Imbiriba, Luis A.; Houzel, Jean C.; Franca, João G.

    2012-01-01

    The rat primary somatosensory cortex (S1) is remarkable for its conspicuous vertical compartmentalization in barrels and septal columns, which are additionally stratified in horizontal layers. Whereas excitatory neurons from each of these compartments perform different types of processing, the role of interneurons is much less clear. Among the numerous types of GABAergic interneurons, those producing nitric oxide (NO) are especially puzzling, since this gaseous messenger can modulate neural activity, synaptic plasticity, and neurovascular coupling. We used a quantitative morphological approach to investigate whether nitrergic interneurons, which might therefore be considered both as NO volume diffusers and as elements of local circuitry, display features that could relate to barrel cortex architecture. In fixed brain sections, nitrergic interneurons can be revealed by histochemical processing for NADPH-diaphorase (NADPHd). Here, the dendritic arbors of nitrergic neurons from different compartments of area S1 were 3D reconstructed from serial 200 μm thick sections, using 100x objective and the Neurolucida system. Standard morphological parameters were extracted for all individual arbors and compared across columns and layers. Wedge analysis was used to compute dendritic orientation indices. Supragranular (SG) layers displayed the highest density of nitrergic neurons, whereas layer IV contained nitrergic neurons with largest soma area. The highest nitrergic neuronal density was found in septa, where dendrites were previously characterized as more extense and ramified than in barrels. Dendritic arbors were not confined to the boundaries of the column nor layer of their respective soma, being mostly double-tufted and vertically oriented, except in SG layers. These data strongly suggest that nitrergic interneurons adapt their morphology to the dynamics of processing performed by cortical compartments. PMID:23133407

  2. Effects of flurbiprofen enantiomers on pain-related chemo-somatosensory evoked potentials in human subjects.

    PubMed

    Lötsch, J; Geisslinger, G; Mohammadian, P; Brune, K; Kobal, G

    1995-10-01

    1. The aim of the study was to investigate the analgesic effects of flurbiprofen enantiomers using an experimental pain model based on both chemo-somatosensory event-related potentials (CSSERP) and subjective pain ratings. 2. Healthy female volunteers (n = 16, age 23-36 years) participated in a placebo-controlled, randomised, double-blind, four-way crossover study. Single doses of (S)-flurbiprofen (50 mg), (R)-flurbiprofen (50 and 100 mg) and placebo were administered orally. Measurements were taken before and 2 h after administration of the medications. During each measurement, 32 painful stimuli of gaseous carbon dioxide (200 ms duration, interval approximately 30 s) of two concentrations (60 and 65% CO2 v/v) were applied to the right nostril. EEG was recorded from five positions and CSSERP were obtained in response to the painful CO2- stimuli. Additionally, subjects rated the perceived intensity of the painful stimuli by means of a visual analogue scale (VAS). 3. The CSSERP-amplitude P2, a measure of analgesic effect, decreased after administration of both (R)- and (S)-flurbiprofen, while it increased after placebo. This was statistically significant at recording positions C4 (P < 0.01) and Fz (P < 0.05). The analgesia-related decreases in evoked potential produced by (R)-flurbiprofen were dose-dependent. Comparing similar doses of (R)- and (S)-flurbiprofen, the decrease in CSSERP-amplitudes produced by the (S)-enantiomer was somewhat more pronounced, indicating a higher analgesic potency. 4. The present data indicate that both enantiomers of flurbiprofen produce analgesic effects. Since (R)-flurbiprofen caused only little toxicity in rats as compared with the (S)-enantiomer or the racemic compound, a reduction of the quantitatively most important side effects in the gastrointestinal tract might be achieved by employing (R)-flurbiprofen in pain therapy.

  3. Somatosensory evoked potentials assess the efficacy of circumcision for premature ejaculation.

    PubMed

    Xia, J-D; Jiang, H-S; Zhu, L-L; Zhang, Z; Chen, H; Dai, Y-T

    2016-07-01

    To assess the efficacy and mechanism of circumcision in the treatment of premature ejaculation (PE) with redundant prepuce, we enrolled a total of 81 PE patients who received circumcision. The patients' ejaculatory ability and sexual performances were evaluated before and after circumcision by using questionnaires (Intravaginal ejaculation latency time (IELT), Chinese Index of PE with 5 questions (CIPE-5) and International Index of Erectile function- 5 (IIEF-5)). Furthermore, somatosensory evoked potentials (SEPs) including dorsal nerve (DNSEP) and glans penis (GPSEP) of the patients were also measured. The mean IELTs of preoperation and post operation were 1.10±0.55 and 2.48±2.03 min, respectively (P<0.001). In addition, the geometric mean IELT after operation was 2.16 min, compared with the baseline 1.07 min before the operation, the fold increase of the IELT was 2.02. Compared with the uncircumcised status, scores of CIPE-5 showed a significant increase after circumcision (P<0.001). The mean latencies (and amplitudes) of GPSEP and DNSEP were 38.1±4.0 ms (3.0±1.9 uV) and 40.5±3.4 ms (2.8±1.6 uV) before circumcision, respectively; and 42.8±3.3 ms (2.8±1.6 uV) and 40.5±4.1 ms (2.4±1.2 uV) in the follow-up end point after circumcision. Only the latencies of GPSEP showed significant prolongation before and after circumcision (P<0.001). The ejaculation time improvement after circumcision is so small, and equal to placebo response, therefore it could not be interpreted as a therapeutic method in men with PE. PMID:27193064

  4. Somatosensory evoked changes in cerebral oxygen consumption measured non-invasively in premature neonates

    PubMed Central

    Roche-Labarbe, Nadege; Fenoglio, Angela; Radakrishnan, Harsha; Kocienski-Filip, Marcia; Carp, Stefan A.; Dubb, Jay; Boas, David A.; Grant, P. Ellen; Franceschini, Maria Angela

    2013-01-01

    The hemodynamic functional response is used as a reliable marker of neuronal activity in countless studies of brain function and cognition. In newborns and infants, however, conflicting results have appeared in the literature concerning the typical response, and there is little information on brain metabolism and functional activation. Measurement of all hemodynamic components and oxygen metabolism is critical for understanding neurovascular coupling in the developing brain. To this end, we combined multiple near infrared spectroscopy techniques to measure oxy- and deoxy-hemoglobin concentrations, cerebral blood volume (CBV), and relative cerebral blood flow (CBF) in the somatosensory cortex of 6 preterm neonates during passive tactile stimulation of the hand. By combining these measures we estimated relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2). CBF starts increasing immediately after stimulus onset, and returns to baseline before blood volume. This is consistent with the model of pre-capillary arteriole active dilation driving the CBF response, with a subsequent CBV increase influenced by capillaries and veins dilating passively to accommodate the extra blood. rCMRO2 estimated using the steady-state formulation shows a biphasic pattern: an increase immediately after stimulus onset, followed by a post-stimulus undershoot due to blood flow returning faster to baseline than oxygenation. However, assuming a longer mean transit time from the arterial to the venous compartment, due to the immature vascular system of premature infants, reduces the post-stimulus undershoot and increases the flow/consumption ratio to values closer to adult values reported in the literature. We are the first to report changes in local rCBF and rCMRO2 during functional activation in preterm infants. The ability to measure these variables in addition to hemoglobin concentration changes is critical for understanding neurovascular coupling in the developing

  5. Central poststroke pain: somatosensory abnormalities and the presence of associated myofascial pain syndrome

    PubMed Central

    2012-01-01

    Background Central post-stroke pain (CPSP) is a neuropathic pain syndrome associated with somatosensory abnormalities due to central nervous system lesion following a cerebrovascular insult. Post-stroke pain (PSP) refers to a broader range of clinical conditions leading to pain after stroke, but not restricted to CPSP, including other types of pain such as myofascial pain syndrome (MPS), painful shoulder, lumbar and dorsal pain, complex regional pain syndrome, and spasticity-related pain. Despite its recognition as part of the general PSP diagnostic possibilities, the prevalence of MPS has never been characterized in patients with CPSP patients. We performed a cross-sectional standardized clinical and radiological evaluation of patients with definite CPSP in order to assess the presence of other non-neuropathic pain syndromes, and in particular, the role of myofascial pain syndrome in these patients. Methods CPSP patients underwent a standardized sensory and motor neurological evaluation, and were classified according to stroke mechanism, neurological deficits, presence and profile of MPS. The Visual Analogic Scale (VAS), McGill Pain Questionnaire (MPQ), and Beck Depression Scale (BDS) were filled out by all participants. Results Forty CPSP patients were included. Thirty-six (90.0%) had one single ischemic stroke. Pain presented during the first three months after stroke in 75.0%. Median pain intensity was 10 (5 to 10). There was no difference in pain intensity among the different lesion site groups. Neuropathic pain was continuous-ongoing in 34 (85.0%) patients and intermittent in the remainder. Burning was the most common descriptor (70%). Main aggravating factors were contact to cold (62.5%). Thermo-sensory abnormalities were universal. MPS was diagnosed in 27 (67.5%) patients and was more common in the supratentorial extra-thalamic group (P <0.001). No significant differences were observed among the different stroke location groups and pain questionnaires and

  6. Objective classification of motion- and direction-sensitive neurons in primary somatosensory cortex of awake monkeys.

    PubMed

    Warren, S; Hamalainen, H A; Gardner, E P

    1986-09-01

    In order to classify movement-sensitive neurons in SI cortex, and to estimate their relative distribution, we have developed a new simple method for controlled motion of textured surfaces across the skin, as well as a set of objective criteria for determining direction selectivity. Moving stimuli were generated using 5 mm thick precision gear wheels, whose teeth formed a grafting. They were mounted on the shafts of low-torque potentiometers (to measure the speed and direction of movement) and rolled manually across the skin using the potentiometer shaft as an axle. As the grafting wheel was advanced, its ridges sequentially contacted a specific set of points on the skin, leaving gaps of defined spacing that were unstimulated. This stimulus was reproducible from trial to trial and produced little distention of the skin. Three objective criteria were used to categorize responses: the ratio of responses to motion in the most and least preferred directions [direction index (DI)], the difference between mean firing rates in the two directions divided by the average standard deviation [index of discriminability (delta'e)], and statistical tests. Neurons were classified as direction sensitive if DI greater than 35, delta's greater than or equal to 1.35 (equivalent to 75% correct discrimination by an unbiased observer), and firing rates in most- and least-preferred directions were significantly different (P less than 0.05). Good agreement was found between the three classification schemes. Recordings were made from 1,020 cortical neurons in the hand and forearm regions of primary somatosensory cortex (areas 3b, 1 and 2) of five macaque monkeys. Tangential motion across the skin was found to be an extremely effective stimulus for SI cortical neurons. Two hundred eighty six of 757 tactile neurons (38%) responded more vigorously to moving stimuli than to pressure or tapping the skin. One hundred twenty-one cells were tested with moving gratings and were classified according

  7. The Role of Attention in Somatosensory Processing: A Multi-Trait, Multi-Method Analysis

    ERIC Educational Resources Information Center

    Wodka, Ericka L.; Puts, Nicolaas A. J.; Mahone, E. Mark; Edden, Richard A. E.; Tommerdahl, Mark; Mostofsky, Stewart H.

    2016-01-01

    Sensory processing abnormalities in autism have largely been described by parent report. This study used a multi-method (parent-report and measurement), multi-trait (tactile sensitivity and attention) design to evaluate somatosensory processing in ASD. Results showed multiple significant within-method (e.g., parent report of different…

  8. Left Lateralized Enhancement of Orofacial Somatosensory Processing Due to Speech Sounds

    ERIC Educational Resources Information Center

    Ito, Takayuki; Johns, Alexis R.; Ostry, David J.

    2013-01-01

    Purpose: Somatosensory information associated with speech articulatory movements affects the perception of speech sounds and vice versa, suggesting an intimate linkage between speech production and perception systems. However, it is unclear which cortical processes are involved in the interaction between speech sounds and orofacial somatosensory…

  9. Electrophysiological Evidence for a Sensory Recruitment Model of Somatosensory Working Memory.

    PubMed

    Katus, Tobias; Grubert, Anna; Eimer, Martin

    2015-12-01

    Sensory recruitment models of working memory assume that information storage is mediated by the same cortical areas that are responsible for the perceptual processing of sensory signals. To test this assumption, we measured somatosensory event-related brain potentials (ERPs) during a tactile delayed match-to-sample task. Participants memorized a tactile sample set at one task-relevant hand to compare it with a subsequent test set on the same hand. During the retention period, a sustained negativity (tactile contralateral delay activity, tCDA) was elicited over primary somatosensory cortex contralateral to the relevant hand. The amplitude of this component increased with memory load and was sensitive to individual limitations in memory capacity, suggesting that the tCDA reflects the maintenance of tactile information in somatosensory working memory. The tCDA was preceded by a transient negativity (N2cc component) with a similar contralateral scalp distribution, which is likely to reflect selection of task-relevant tactile stimuli at the encoding stage. The temporal sequence of N2cc and tCDA components mirrors previous observations from ERP studies of working memory in vision. The finding that the sustained somatosensory delay period activity varies as a function of memory load supports a sensory recruitment model for spatial working memory in touch.

  10. Detection of Optogenetic Stimulation in Somatosensory Cortex by Non-Human Primates - Towards Artificial Tactile Sensation

    PubMed Central

    Brush, Benjamin; Borton, David; Wagner, Fabien; Agha, Naubahar; Sheinberg, David L.; Nurmikko, Arto V.

    2014-01-01

    Neuroprosthesis research aims to enable communication between the brain and external assistive devices while restoring lost functionality such as occurs from stroke, spinal cord injury or neurodegenerative diseases. In future closed-loop sensorimotor prostheses, one approach is to use neuromodulation as direct stimulus to the brain to compensate for a lost sensory function and help the brain to integrate relevant information for commanding external devices via, e.g. movement intention. Current neuromodulation techniques rely mainly of electrical stimulation. Here we focus specifically on the question of eliciting a biomimetically relevant sense of touch by direct stimulus of the somatosensory cortex by introducing optogenetic techniques as an alternative to electrical stimulation. We demonstrate that light activated opsins can be introduced to target neurons in the somatosensory cortex of non-human primates and be optically activated to create a reliably detected sensation which the animal learns to interpret as a tactile sensation localized within the hand. The accomplishment highlighted here shows how optical stimulation of a relatively small group of mostly excitatory somatosensory neurons in the nonhuman primate brain is sufficient for eliciting a useful sensation from data acquired by simultaneous electrophysiology and from behavioral metrics. In this first report to date on optically neuromodulated behavior in the somatosensory cortex of nonhuman primates we do not yet dissect the details of the sensation the animals exerience or contrast it to those evoked by electrical stimulation, issues of considerable future interest. PMID:25541938

  11. Somatosensory effects of action inhibition: a study with the stop-signal paradigm.

    PubMed

    Walsh, Eamonn; Haggard, Patrick

    2010-07-01

    When a weak shock is delivered to the finger immediately before a voluntary movement, or during a delay interval where subjects are prepared to make the movement, shock detection rates worsen progressively as the movement approaches. Further, we previously showed that shock detection improves again if a NoGo signal produces inhibition of a prepared response. Here, we used a somatosensory version of the stop-signal paradigm to investigate inhibitory processing during the 'horserace' period when motor excitation and inhibition processes may be simultaneously active. When subjects made a rapid keypress response to a go-signal, shock detection deteriorated in a time-dependent manner, replicating sensory suppression. However, when go-signals were followed by adaptively delayed stop-signals so that subjects could not inhibit the prepared movement, and made errors of commission, we found a paradoxical brief increase in shock detection performance just after the stop-signal, as if in a NoGo trial. During this brief window, the somatosensory system showed a pattern consistent with motor inhibition, even though the motor system itself was too far advanced in movement execution for action to be inhibited. Most models of stop-signal processing propose a two-horse race between excitation and inhibition, with a winner-takes-all solution. We show that there may be distinct motor and somatosensory races. Moreover, inhibitory processes may lead in the somatosensory race, at least briefly, even when excitatory processes win the motor race.

  12. Spinal pathways mediating somatosensory evoked potentials from cutaneous and muscle nerves in the cat.

    PubMed

    Ducati, A; Schieppati, M

    1980-01-01

    The Authors give evidence on the function of a pathway mediating somatosensory evoked potentials (SEPs) from muscle nerves, other than the dorsal columns: physiological and anatomical data prove its location to be in the spinothalamic tract. Previous contrasting results on the topic are discussed.

  13. Pain perception: predictive value of sex, depression, anxiety, somatosensory amplification, obesity, and age

    PubMed Central

    Kivrak, Yuksel; Kose-Ozlece, Hatice; Ustundag, Mehmet Fatih; Asoglu, Mehmet

    2016-01-01

    Objective Factors affecting pain sensation are still being investigated. In this study, we aimed to examine the effects of sex, age, body mass index (BMI), somatosensory amplification, anxiety, and depression on the perception of pain. Methods Venipuncture was performed on 140 healthy individuals. All the cases completed a sociodemographic data form, visual analog scale (VAS), Beck Anxiety Inventory (BAI), Beck Depression Inventory, and Somatosensory Amplification Scale. Height and weight were also measured. Results When both the sexes were compared, there was no difference in terms of VAS, BMI, age, and Beck Depression Inventory, but Somatosensory Amplification Scale and BAI were found to be higher in females. A correlation was found among VAS points, BAI, and BMI. The results of a regression analysis show that the BAI score is a predictor for the VAS score. Conclusion These results indicate that anxiety may be a predictor of pain, whereas sex, depression, somatosensory amplification, age, and weight do not appear to influence the perception of pain. PMID:27536113

  14. Psychophysical methods for the measurement of somatosensory dysfunction of laboratory animals.

    PubMed Central

    Cabe, P A

    1982-01-01

    Somatosensory dysfunction is a widely reported clinical consequence of chemical exposure. Assessment of such dysfunction should be an important component of agent safety testing, necessarily implying evaluation of psychophysical functions in laboratory animals. The logic of testing agent-induced sensory dysfunction, conceptual and practical factors affecting such tests, and the categories of experimental methods available are reviewed. PMID:7044779

  15. Functional assays of local connectivity in the somatosensory cortex of individuals with autism.

    PubMed

    Coskun, Mehmet Akif; Loveland, Katherine A; Pearson, Deborah A; Papanicolaou, Andrew C; Sheth, Bhavin R

    2013-06-01

    Emerging evidence for differences between individuals with autism spectrum disorder (ASD) and neurotypical (NT) individuals in somatic processing and brain response to touch suggests somatosensory cortex as a promising substrate for elucidating differences in functional brain connectivity between individuals with and without autism. Signals from adjacent digits project to neighboring locations or representations in somatosensory cortex. When a digit is stimulated, i.e. touched, its representation in cortex is directly activated; local intracortical connections indirectly activate nonprimary cortical representations corresponding to adjacent digits. The response of the nonprimary cortical representations is thus a proxy for connection strength. Local overconnectivity in autism implies that the nonprimary/primary response ratios of the ASD group will be higher than those of the NT group. D1 and D2 of the dominant hand of the participant were individually stimulated while we recorded neural responses using magnetoencephalography. The cortical representations of D1 and D2 (somatosensory-evoked fields) were computed from the ensemble-averaged data using (a) dipole model fits and (b) singular value decomposition. Individual adjacent/primary response ratios were measured, and group response ratio data were fitted with straight lines. Local overconnectivity in autism implies steeper ASD vs. NT group slopes. Our findings did not support local overconnectivity. Slopes were found to be significantly shallower for the ASD group than the NT group. Our findings support the idea of local underconnectivity in the somatosensory cortex of the brains of individuals with ASD. PMID:23427110

  16. A Somatosensory Latency between the Thalamus and Cortex also Correlates with Level of Intelligence.

    ERIC Educational Resources Information Center

    Reed, T. Edward; Jensen, Arthur R.

    1993-01-01

    Results for sensory thalamocortical latency (3 somatosensory evoked potentials) for 205 college students agree with data that correlate a more extensive visual evoked potential latency with intelligence quotient. Findings suggest that the correlation occurs because the latency indexes cortical nerve conduction velocity. (SLD)

  17. Changes in somatosensory-evoked potentials and high-frequency oscillations after paired-associative stimulation.

    PubMed

    Murakami, Takenobu; Sakuma, Kenji; Nomura, Takashi; Uemura, Yusuke; Hashimoto, Isao; Nakashima, Kenji

    2008-01-01

    Paired-associative stimulation (PAS), combining electrical median nerve stimulation with transcranial magnetic stimulation (TMS) with a variable delay, causes long-term potentiation or depression (LTP/LTD)-like cortical plasticity. In the present study, we examined how PAS over the motor cortex affected a distant site, the somatosensory cortex. Furthermore, the influences of PAS on high-frequency oscillations (HFOs) were investigated to clarify the origin of HFOs. Interstimulus intervals between median nerve stimulation and TMS were 25 ms (PAS(25)) and 10 ms (PAS(10)). PAS was performed over the motor and somatosensory cortices. SEPs following median nerve stimulation were recorded before and after PAS. HFOs were isolated by 400-800 Hz band-pass filtering. PAS(25) over the motor cortex increased the N20-P25 and P25-N33 amplitudes and the HFOs significantly. The enhancement of the P25-N33 amplitude and the late HFOs lasted more than 60 min. After PAS(10) over the motor cortex, the N20-P25 and P25-N33 amplitudes decreased for 40 min, and the HFOs decreased for 60 min. Frontal SEPs were not affected after PAS over the motor cortex. PAS(25/10) over the somatosensory cortex did not affect SEPs and HFOs. PAS(25/10) over the motor cortex caused the LTP/LTD-like phenomena in a distant site, the somatosensory cortex. The PAS paradigms over the motor cortex can modify both the neural generators of SEPs and HFOs. HFOs may reflect the activation of GABAergic inhibitory interneurons regulating pyramidal neurons in the somatosensory cortex. PMID:17724581

  18. Effects of bicuculline application on the somatosensory responses of secondary vestibular neurons.

    PubMed

    Grasso, C; Li Volsi, G; Cataldo, E; Manzoni, D; Barresi, M

    2016-10-29

    Limb somatosensory signals modify the discharge of vestibular neurons and elicit postural reflexes, which stabilize the body position. The aim of this study was to investigate the contribution of the γ-amino-butyric-acid (GABA) to the responsiveness of vestibular neurons to somatosensory inputs. The activity of 128 vestibular units was recorded in anesthetized rats in resting conditions and during sinusoidal foreleg rotation around the elbow or shoulder joints (0.026-0.625Hz, 45° peak amplitude). None of the recorded units was influenced by elbow rotation, while 40% of them responded to shoulder rotation. The selective GABAA antagonist receptor, bicuculline methiodine (BIC), was applied by microiontophoresis on single vestibular neurons and the changes in their activity at rest and during somatosensory stimulation was studied. In about half of cells the resting activity increased after the BIC application: 75% of these neurons showed also an increased response to somatosensory inputs whereas 17% exhibited a decrease. Changes in responsiveness in both directions were detected also in the units whose resting activity was not influenced by BIC. These data suggest that the responses of vestibular neurons to somatosensory inputs are modulated by GABA through a tonic release, which modifies the membrane response to the synaptic current. It is also possible that a phasic release of GABA occurs during foreleg rotation, shaping the stimulus-elicited current passing through the membrane. If this is the case, the changes in the relative position of body segments would modify the GABA release inducing changes in the vestibular reflexes and in learning processes that modify their spatio-temporal development.

  19. Effects of bicuculline application on the somatosensory responses of secondary vestibular neurons.

    PubMed

    Grasso, C; Li Volsi, G; Cataldo, E; Manzoni, D; Barresi, M

    2016-10-29

    Limb somatosensory signals modify the discharge of vestibular neurons and elicit postural reflexes, which stabilize the body position. The aim of this study was to investigate the contribution of the γ-amino-butyric-acid (GABA) to the responsiveness of vestibular neurons to somatosensory inputs. The activity of 128 vestibular units was recorded in anesthetized rats in resting conditions and during sinusoidal foreleg rotation around the elbow or shoulder joints (0.026-0.625Hz, 45° peak amplitude). None of the recorded units was influenced by elbow rotation, while 40% of them responded to shoulder rotation. The selective GABAA antagonist receptor, bicuculline methiodine (BIC), was applied by microiontophoresis on single vestibular neurons and the changes in their activity at rest and during somatosensory stimulation was studied. In about half of cells the resting activity increased after the BIC application: 75% of these neurons showed also an increased response to somatosensory inputs whereas 17% exhibited a decrease. Changes in responsiveness in both directions were detected also in the units whose resting activity was not influenced by BIC. These data suggest that the responses of vestibular neurons to somatosensory inputs are modulated by GABA through a tonic release, which modifies the membrane response to the synaptic current. It is also possible that a phasic release of GABA occurs during foreleg rotation, shaping the stimulus-elicited current passing through the membrane. If this is the case, the changes in the relative position of body segments would modify the GABA release inducing changes in the vestibular reflexes and in learning processes that modify their spatio-temporal development. PMID:27579770

  20. Cerebellar inhibitory output shapes the temporal dynamics of its somatosensory inferior olivary input.

    PubMed

    Hogri, Roni; Segalis, Eyal; Mintz, Matti

    2014-08-01

    The cerebellum is necessary and sufficient for the acquisition and execution of adaptively timed conditioned motor responses following repeated paired presentations of a conditioned stimulus and an unconditioned stimulus. The underlying plasticity depends on the convergence of conditioned and unconditioned stimuli signals relayed to the cerebellum by the pontine nucleus and the inferior olive (IO), respectively. Adaptive timing of conditioned responses relies on the correctly predicted onset of the unconditioned stimulus, usually a noxious somatosensory stimulus. We addressed two questions: First, does the IO relay information regarding the duration of somatosensory stimuli to the cerebellum? Multiple-unit recordings from the IO of anesthetized rats that received periorbital airpuffs of various durations revealed that sustained somatosensory stimuli are invariably transformed into phasic IO outputs. The phasic response was followed by a post-peak depression in IO activity as compared to baseline, providing the cerebellum with a highly synchronous signal, time-locked to the stimulus' onset. Second, we sought to examine the involvement of olivocerebellar interactions in this signal transformation. Cerebello-olivary inhibition was interrupted using temporary pharmacological inactivation of cerebellar output nuclei, resulting in more sustained (i.e., less synchronous) IO responses to sustained somatosensory stimuli, in which the post-peak depression was substituted with elevated activity as compared to baseline. We discuss the possible roles of olivocerebellar negative-feedback loops and baseline cerebello-olivary inhibition levels in shaping the temporal dynamics of the IO's response to somatosensory stimuli and the consequences of this shaping for cerebellar plasticity and its ability to adapt to varying contexts.

  1. 'Colored' and Decorative Contact Lenses: A Prescription Is a Must

    MedlinePlus

    ... labeling. (See additional information about cleaning solutions with hydrogen peroxide on the FDA website.) See your eye ... For More Information Decorative Contact Lenses Contact Lenses Hydrogen Peroxide Solution Related Consumer Updates Focusing on Contact ...

  2. Somatosensory Psychophysical Losses in Inhabitants of Riverside Communities of the Tapajós River Basin, Amazon, Brazil: Exposure to Methylmercury Is Possibly Involved.

    PubMed

    Khoury, Eliana Dirce Torres; Souza, Givago da Silva; da Costa, Carlos Araújo; de Araújo, Amélia Ayako Kamogari; de Oliveira, Cláudia Simone Baltazar; Silveira, Luiz Carlos de Lima; Pinheiro, Maria da Conceição Nascimento

    2015-01-01

    a weak linear correlation between tactile sensation threshold and mercury concentration in the head hair samples. No correlation was found for the other two measurements. Mercury-exposed subjects had impaired somatosensory function compared with non-exposed control subjects. Long-term mercury exposure of riverside communities in the Tapajós river basin is a possible but not a definitely proven cause for psychophysical somatosensory losses observed in their population. Additionally, the relatively simple psychophysical measures used in this work should be followed by more rigorous measures of the same population.

  3. Somatosensory Psychophysical Losses in Inhabitants of Riverside Communities of the Tapajós River Basin, Amazon, Brazil: Exposure to Methylmercury Is Possibly Involved

    PubMed Central

    Khoury, Eliana Dirce Torres; Souza, Givago da Silva; da Costa, Carlos Araújo; de Araújo, Amélia Ayako Kamogari; de Oliveira, Cláudia Simone Baltazar; Silveira, Luiz Carlos de Lima; Pinheiro, Maria da Conceição Nascimento

    2015-01-01

    . There was a weak linear correlation between tactile sensation threshold and mercury concentration in the head hair samples. No correlation was found for the other two measurements. Mercury-exposed subjects had impaired somatosensory function compared with non-exposed control subjects. Long-term mercury exposure of riverside communities in the Tapajós river basin is a possible but not a definitely proven cause for psychophysical somatosensory losses observed in their population. Additionally, the relatively simple psychophysical measures used in this work should be followed by more rigorous measures of the same population. PMID:26658153

  4. Somatosensory Psychophysical Losses in Inhabitants of Riverside Communities of the Tapajós River Basin, Amazon, Brazil: Exposure to Methylmercury Is Possibly Involved.

    PubMed

    Khoury, Eliana Dirce Torres; Souza, Givago da Silva; da Costa, Carlos Araújo; de Araújo, Amélia Ayako Kamogari; de Oliveira, Cláudia Simone Baltazar; Silveira, Luiz Carlos de Lima; Pinheiro, Maria da Conceição Nascimento

    2015-01-01

    a weak linear correlation between tactile sensation threshold and mercury concentration in the head hair samples. No correlation was found for the other two measurements. Mercury-exposed subjects had impaired somatosensory function compared with non-exposed control subjects. Long-term mercury exposure of riverside communities in the Tapajós river basin is a possible but not a definitely proven cause for psychophysical somatosensory losses observed in their population. Additionally, the relatively simple psychophysical measures used in this work should be followed by more rigorous measures of the same population. PMID:26658153

  5. Elastohydrodynamic lubrication of elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1981-01-01

    The determination of the minimum film thickness within contact is considered for both fully flooded and starved conditions. A fully flooded conjunction is one in which the film thickness is not significantly changed when the amount of lubricant is increased. The fully flooded results presented show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. These results are applied to materials of high elastic modulus (hard EHL), such as metal, and to materials of low elastic modulus(soft EHL), such as rubber. In addition to the film thickness equations that are developed, contour plots of pressure and film thickness are given which show the essential features of elastohydrodynamically lubricated conjunctions. The crescent shaped region of minimum film thickness, with its side lobes in which the separation between the solids is a minimum, clearly emerges in the numerical solutions. In addition to the 3 presented for the fully flooded results, 15 more cases are used for hard EHL contacts and 18 cases are used for soft EHL contacts in a theoretical study of the influence of lubricant starvation on film thickness and pressure. From the starved results for both hard and soft EHL contacts, a simple and important dimensionless inlet boundary distance is specified. This inlet boundary distance defines whether a fully flooded or a starved condition exists in the contact. Contour plots of pressure and film thickness in and around the contact are shown for conditions.

  6. Contact modeling for robotics applications

    SciTech Connect

    Lafarge, R.A.; Lewis, C.

    1998-08-01

    At Sandia National Laboratories (SNL), the authors are developing the ability to accurately predict motions for arbitrary numbers of bodies of arbitrary shapes experiencing multiple applied forces and intermittent contacts. In particular, the authors are concerned with the simulation of systems such as part feeders or mobile robots operating in realistic environments. Preliminary investigation of commercial dynamics software packages led them to the conclusion that they could use commercial software to provide everything they needed except for the contact model. They found that ADAMS best fit their needs for a simulation package. To simulate intermittent contacts, they need collision detection software that can efficiently compute the distances between non-convex objects and return the associated witness features. They also require a computationally efficient contact model for rapid simulation of impact, sustained contact under load, and transition to and from contact conditions. This paper provides a technical review of a custom hierarchical distance computation engine developed at Sandia, called the C-Space Toolkit (CSTk). In addition, they describe an efficient contact model using a non-linear damping term developed by SNL and Ohio State. Both the CSTk and the non-linear damper have been incorporated in a simplified two-body testbed code, which is used to investigate how to correctly model the contact using these two utilities. They have incorporated this model into the ADAMS software using the callable function interface. An example that illustrates the capabilities of the 9.02 release of ADAMS with their extensions is provided.

  7. [Contact allergy from cigarette smoking].

    PubMed

    Rat, J P; Larregue, M

    1987-04-01

    Usually, recorded cases of allergic contact dermatitis to tobacco are confined to occupational diseases and involve agricultural workers and those engaged in manufacturing or selling the products, all of whom are in contact with tobacco leaves. We have found three cases of contact dermatitis caused by cigarette smoke, which are not occupational disease. We do not know what offending agent is, but in one case the patient is allergic to perfume and this may be the factor responsible, since she smokes only flavoured cigarettes. In addition, we need to know whether the allergen only appears during combustion and is therefore present only in cigarette smoke.

  8. The primary somatosensory cortex and the insula contribute differently to the processing of transient and sustained nociceptive and non-nociceptive somatosensory inputs.

    PubMed

    Hu, Li; Zhang, Li; Chen, Rui; Yu, Hongbo; Li, Hong; Mouraux, André

    2015-11-01

    Transient nociceptive stimuli elicit consistent brain responses in the primary and secondary somatosensory cortices (S1, S2), the insula and the anterior and mid-cingulate cortex (ACC/MCC). However, the functional significance of these responses, especially their relationship with sustained pain perception, remains largely unknown. Here, using functional magnetic resonance imaging, we characterize the differential involvement of these brain regions in the processing of sustained nociceptive and non-nociceptive somatosensory input. By comparing the spatial patterns of activity elicited by transient (0.5 ms) and long-lasting (15 and 30 s) stimuli selectively activating nociceptive or non-nociceptive afferents, we found that the contralateral S1 responded more strongly to the onset of non-nociceptive stimulation as compared to the onset of nociceptive stimulation and the sustained phases of nociceptive and non-nociceptive stimulation. Similarly, the anterior insula responded more strongly to the onset of nociceptive stimulation as compared to the onset of non-nociceptive stimulation and the sustained phases of nociceptive and non-nociceptive stimulation. This suggests that S1 is specifically sensitive to changes in incoming non-nociceptive input, whereas the anterior insula is specifically sensitive to changes in incoming nociceptive input. Second, we found that the MCC responded more strongly to the onsets as compared to the sustained phases of both nociceptive and non-nociceptive stimulation, suggesting that it could be involved in the detection of change regardless of sensory modality. Finally, the posterior insula and S2 responded maximally during the sustained phase of non-nociceptive stimulation but not nociceptive stimulation, suggesting that these regions are preferentially involved in processing non-nociceptive somatosensory input. PMID:26252509

  9. Spatial segregation of somato-sensory and pain activations in the human operculo-insular cortex.

    PubMed

    Mazzola, Laure; Faillenot, Isabelle; Barral, Fabrice-Guy; Mauguière, François; Peyron, Roland

    2012-03-01

    The role of operculo-insular region in the processing of somato-sensory inputs, painful or not, is now well established. However, available maps from previous literature show a substantial overlap of cortical areas activated by these stimuli, and the region referred to as the "secondary somatosensory area (SII)" is widely distributed in the parietal operculum. Differentiating SII from posterior insula cortex, which is anatomically contiguous, is not easy, explaining why the "operculo-insular" label has been introduced to describe activations by somatosensory stimuli in this cortical region. Based on the recent cyto-architectural parcellation of the human insular/SII cortices (Eickhoff et al., 2006, Kurth et al., 2010), the present study investigates with functional MRI (fMRI), whether these structural subdivisions could subserve distinct aspects of discriminative somato-sensory functions, including pain. Responses to five types of stimuli applied on the left hand of 25 healthy volunteers were considered: i) tactile stimuli; ii) passive movements; iii) innocuous cold stimuli; iv) non-noxious warm and v) heat pain. Our results show different patterns of activation depending on the type of somato-sensory stimulation. The posterior part of SII (OP1 area), contralateral to stimuli, was the only sub-region activated by all type of stimuli and might therefore be considered as a common cortical target for different types of somato-sensory inputs. Proprioceptive stimulation by passive finger movements activated the posterior part of SII (OP1 sub-region) bilaterally and the contralateral median part of insula (PreCG and MSG). Innocuous cooling activated the contralateral posterior part of SII (OP1) and the dorsal posterior and median part of insula (OP2, PostCG). Pain stimuli induced the most widespread and intense activation that was bilateral in SII (OP1, OP4) and distributed to all sub-regions of contralateral insula (except OP2) and to the anterior part of the

  10. Adhesion in hydrogel contacts

    NASA Astrophysics Data System (ADS)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  11. Irritant Contact Dermatitis

    MedlinePlus

    ... and rashes clinical tools newsletter | contact Share | Irritant Contact Dermatitis Information for adults A A A This ... severe involvement in the patient's armpit. Overview Irritant contact dermatitis is an inflammatory rash caused by direct ...

  12. Contact Lens Risks

    MedlinePlus

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  13. Contact Lens Care

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More ... 1088, www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative ...

  14. Contact Lens Solution Toxicity

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  15. Somatosensory evoked potentials can be recorded on the midline of the skull with subdermal electrodes in non-sedated rats elicited by magnetic stimulation of the tibial nerve.

    PubMed

    Zhang, Shu-Xin; Huang, Fengfa; Gates, Mary; Holmberg, Eric G

    2012-07-15

    Somatosensory evoked potentials (SSEPs) are a sensitive quantitative measure of conduction in somatosensory pathways of the central nervous system and are increasingly used in both clinical trials and animal experiments. SSEPs can be recorded in non-sedated rodents by magnetic stimulation (MS) of peripheral nerves. To overcome some disadvantages caused by using anesthesia and implanted recording electrodes, we used subdermal needle electrodes located on the midline of the skull to successfully record SSEPs in non-sedated rats, elicited by stimulating the tibial nerve with a magnetic stimulator. The wave form contains a typical P1 peak and N1 peak. Although there is a variation of P1 latency, N1 latency, and P1-N1 amplitude between right side and left side, it was not statistically significant. In addition, there is a significantly positive relationship between P1-N1 amplitude and MS strength, suggesting that the increase in magnetic stimulating strength resulted in the increase in P1-N1 amplitude. Results in the present study demonstrate that our modified method is a reliable and feasible paradigm for recording SSEPs in non-sedated rats. PMID:22579876

  16. The interaction between felt touch and tactile consequences of observed actions: an action-based somatosensory congruency paradigm.

    PubMed

    Deschrijver, Eliane; Wiersema, Jan R; Brass, Marcel

    2016-07-01

    Action observation leads to a representation of both the motor aspect of an observed action (motor simulation) and its somatosensory consequences (action-based somatosensory simulation) in the observer's brain. In the current electroencephalography-study, we investigated the neuronal interplay of action-based somatosensory simulation and felt touch. We presented index or middle finger tapping movements of a human or a wooden hand, while simultaneously presenting 'tap-like' tactile sensations to either the corresponding or non-corresponding fingertip of the participant. We focused on an early stage of somatosensory processing [P50, N100 and N140 sensory evoked potentials (SEPs)] and on a later stage of higher-order processing (P3-complex). The results revealed an interaction effect of animacy and congruency in the early P50 SEP and an animacy effect in the N100/N140 SEPs. In the P3-complex, we found an interaction effect indicating that the influence of congruency was larger in the human than in the wooden hand. We argue that the P3-complex may reflect higher-order self-other distinction by signaling simulated action-based touch that does not match own tactile information. As such, the action-based somatosensory congruency paradigm might help understand higher-order social processes from a somatosensory point of view.

  17. Phantom acupuncture: dissociating somatosensory and cognitive/affective components of acupuncture stimulation with a novel form of placebo acupuncture.

    PubMed

    Lee, Jeungchan; Napadow, Vitaly; Kim, Jieun; Lee, Seunggi; Choi, Woojin; Kaptchuk, Ted J; Park, Kyungmo

    2014-01-01

    In a clinical setting, acupuncture treatment consists of multiple components including somatosensory stimulation, treatment context, and attention to needle-based procedures. In order to dissociate somatosensory versus contextual and attentional aspects of acupuncture, we devised a novel form of placebo acupuncture, a visual manipulation dubbed phantom acupuncture, which reproduces the acupuncture needling ritual without somatosensory tactile stimulation. Subjects (N = 20) received both real (REAL) and phantom (PHNT) acupuncture. Subjects were retrospectively classified into two groups based on PHNT credibility (PHNTc, who found phantom acupuncture credible; and PHNTnc, who did not). Autonomic and psychophysical responses were monitored. We found that PHNT can be delivered in a credible manner. Acupuncture needling, a complex, ritualistic somatosensory intervention, induces sympathetic activation (phasic skin conductance [SC] response), which may be specific to the somatosensory component of acupuncture. In contrast, contextual effects, such as needling credibility, are instead associated with a shift toward relative cardiovagal activation (decreased heart rate) during needling and sympathetic inhibition (decreased SC) and parasympathetic activation (decreased pupil size) following acupuncture needling. Visual stimulation characterizing the needling ritual is an important factor for phasic autonomic responses to acupuncture and may undelie the needling orienting response. Our study suggests that phantom acupuncture can be a viable sham control for acupuncture as it completely excludes the somatosensory component of real needling while maintaining the credibility of the acupuncture treatment context in many subjects.

  18. The interaction between felt touch and tactile consequences of observed actions: an action-based somatosensory congruency paradigm.

    PubMed

    Deschrijver, Eliane; Wiersema, Jan R; Brass, Marcel

    2016-07-01

    Action observation leads to a representation of both the motor aspect of an observed action (motor simulation) and its somatosensory consequences (action-based somatosensory simulation) in the observer's brain. In the current electroencephalography-study, we investigated the neuronal interplay of action-based somatosensory simulation and felt touch. We presented index or middle finger tapping movements of a human or a wooden hand, while simultaneously presenting 'tap-like' tactile sensations to either the corresponding or non-corresponding fingertip of the participant. We focused on an early stage of somatosensory processing [P50, N100 and N140 sensory evoked potentials (SEPs)] and on a later stage of higher-order processing (P3-complex). The results revealed an interaction effect of animacy and congruency in the early P50 SEP and an animacy effect in the N100/N140 SEPs. In the P3-complex, we found an interaction effect indicating that the influence of congruency was larger in the human than in the wooden hand. We argue that the P3-complex may reflect higher-order self-other distinction by signaling simulated action-based touch that does not match own tactile information. As such, the action-based somatosensory congruency paradigm might help understand higher-order social processes from a somatosensory point of view. PMID:26152577

  19. Quantifying the effect of isoflurane and nitrous oxide on somatosensory-evoked potentials.

    PubMed

    Devadoss, Usha; Babu, S; Cherian, Vt

    2010-01-01

    Anaesthetic techniques may have a significant effect on intraoperative-evoked potentials (EP). The present study is designed to compare Propofol anaesthesia with Isoflurane (with or without nitrous oxide) during intraoperative somatosensory-evoked potential (SSEP) monitoring in 15 ASA Grade I and II patients undergoing surgery for intracranial tumours. SSEPs in response to median and posterior tibial nerve stimulation were recorded under four different anaesthetic conditions: 1) Propofol infusion and ventilation with air-oxygen, 2) Isoflurane, 1.0 MAC and ventilation with air-oxygen, 3) Isoflurane 1.0 MAC and ventilation with nitrous oxide-oxygen, and 4) Return to Isoflurane, 1.0 MAC and ventilation with air-oxygen. Intraoperative monitoring of somatosensory evoked potentials is best recordable using Propofol. The morphology of the EP is reproducible with Isoflurane. This effect is exaggerated when it is advisable to avoid nitrous oxide. PMID:20532071

  20. Valid cues for auditory or somatosensory targets affect their perception: a signal detection approach.

    PubMed

    Van Hulle, Lore; Van Damme, Stefaan; Crombez, Geert

    2013-01-01

    We investigated the effects of focusing attention towards auditory or somatosensory stimuli on perceptual sensitivity and response bias using a signal detection task. Participants (N = 44) performed an unspeeded detection task in which weak (individually calibrated) somatosensory or auditory stimuli were delivered. The focus of attention was manipulated by the presentation of a visual cue at the start of each trial. The visual cue consisted of the word "warmth" or the word "tone". This word cue was predictive of the corresponding target on two-thirds of the trials. As hypothesised, the results showed that cueing attention to a specific sensory modality resulted in a higher perceptual sensitivity for validly cued targets than for invalidly cued targets, as well as in a more liberal response criterion for reporting stimuli in the valid modality than in the invalid modality. The value of this experimental paradigm for investigating excessive attentional focus or hypervigilance in various non-clinical and clinical populations is discussed.

  1. Visual-Somatosensory Integration is Linked to Physical Activity Level in Older Adults.

    PubMed

    Mahoney, Jeannette R; Dumas, Kristina; Holtzer, Roee

    2015-01-01

    Studies examining multisensory integration (MSI) in aging consistently demonstrate greater reaction time (RT) facilitation in old compared to young adults, but often fail to determine the utility of MSI. The aim of the current experiment was to further elucidate the utility of MSI in aging by determining its relationship to physical activity level. 147 non-demented older adults (mean age 77 years; 57% female) participated. Participants were instructed to make speeded responses to visual, somatosensory, and visual-somatosensory (VS) stimuli. Depending on the magnitude of the individuals' RT facilitation, participants were classified into a MSI or NO MSI group. Physical activity was assessed using a validated physical activity scale. As predicted, RTs to VS stimuli were significantly shorter than those elicited to constituent unisensory conditions. Multisensory RT facilitation was a significant predictor of total number of physical activity days per month, with individuals in the NO MSI group reporting greater engagement in physical activities compared to those requiring greater RT facilitation.

  2. Glutamate-Mediated Primary Somatosensory Cortex Excitability Correlated with Circulating Copper and Ceruloplasmin

    PubMed Central

    Tecchio, Franca; Assenza, Giovanni; Zappasodi, Filippo; Mariani, Stefania; Salustri, Carlo; Squitti, Rosanna

    2011-01-01

    Objective. To verify whether markers of metal homeostasis are related to a magnetoencephalographic index representative of glutamate-mediated excitability of the primary somatosensory cortex. The index is identified as the source strength of the earliest component (M20) of the somatosensory magnetic fields (SEFs) evoked by right median nerve stimulation at wrist. Method. Thirty healthy right-handed subjects (51 ± 22 years) were enrolled in the study. A source reconstruction algorithm was applied to assess the amount of synchronously activated neurons subtending the M20 and the following SEF component (M30), which is generated by two independent contributions of gabaergic and glutamatergic transmission. Serum copper, ceruloplasmin, iron, transferrin, transferrin saturation, and zinc levels were measured. Results. Total copper and ceruloplasmin negatively correlated with the M20 source strength. Conclusion. This pilot study suggests that higher level of body copper reserve, as marked by ceruloplasmin variations, parallels lower cortical glutamatergic responsiveness. PMID:22145081

  3. No Evidence for Threat-Induced Spatial Prioritization of Somatosensory Stimulation during Pain Control Using a Synchrony Judgment Paradigm

    PubMed Central

    Van Damme, Stefaan

    2016-01-01

    Topical research efforts on attention to pain often take a critical look at the modulatory role of top-down factors. For instance, it has been shown that the fearful expectation of pain at a location of the body directs attention towards that body part. In addition, motivated attempts to control this pain were found to modulate this prioritization effect. Such studies have often used a temporal order judgment task, requiring participants to judge the order in which two stimuli are presented by indicating which one they perceived first. As this constitutes a forced-choice response format, such studies may be subject to response bias. The aim of the current study was to address this concern. We used a ternary synchrony judgment paradigm, in which participants judged the order in which two somatosensory stimuli occurred. Critically, participants now also had the option to give a ‘simultaneous’ response when they did not perceive a difference. This way we eliminated the need for guessing, and thus reduced the risk of response bias. One location was threatened with the possibility of pain in half of the trials, as predicted by an auditory cue. Additionally, half of the participants (pain control group) were encouraged to avoid pain stimuli by executing a quick button press. The other half (comparison group) performed a similar action, albeit unrelated to the occurrence of pain. Our data did not support threat-induced spatial prioritization, nor did we find evidence that pain control attempts influenced attention in any way. PMID:27270456

  4. Dizziness and Loss of Balance in Individuals With Diabetes: Relative Contribution of Vestibular Versus Somatosensory Dysfunction

    PubMed Central

    Walley, Megan; Anderson, Elizabeth; Pippen, Mary Walch; Maitland, Gerry

    2014-01-01

    In Brief The authors studied patients with diabetes and complaints of dizziness to determine whether peripheral neuropathy or inner ear dysfunction was more likely to disturb balance. Quantitative testing showed that the majority failed to maintain balance in vestibular-related conditions and had normal equilibrium scores in conditions relying on somatosensory input. Vestibular dysfunction should be an immediate consideration in patients with diabetes and complaints of dizziness regardless of the presence of peripheral neuropathy. PMID:26130865

  5. Enhancement of the amplitude of somatosensory evoked potentials following magnetic pulse stimulation of the human brain.

    PubMed

    Seyal, M; Browne, J K; Masuoka, L K; Gabor, A J

    1993-01-01

    In this study we have demonstrated an enhancement of cortically generated wave forms of the somatosensory evoked potential (SEP) following magnetic pulse stimulation of the human brain. Subcortically generated activity was unaltered. The enhancement of SEP amplitude was greatest when the median nerve was stimulated 30-70 msec following magnetic pulse stimulation over the contralateral parietal scalp. We posit that the enhancement of the SEP is the result of synchronization of pyramidal cells in the sensorimotor cortex resulting from the magnetic pulse.

  6. Children with cerebral palsy have uncharacteristic somatosensory cortical oscillations after stimulation of the hand mechanoreceptors.

    PubMed

    Kurz, M J; Becker, K M; Heinrichs-Graham, E; Wilson, T W

    2015-10-01

    Numerous clinical investigations have reported that children with cerebral palsy (CP) have tactile discrimination deficits that likely limit their ability to plan and manipulate objects. Despite this clinical awareness, we still have a substantial knowledge gap in our understanding of the neurological basis for these tactile discrimination deficits. Previously, we have shown that children with CP have aberrant theta-alpha (4-14 Hz) oscillations in the somatosensory cortices following tactile stimulation of the foot. In this investigation, we evaluated if these aberrant theta-alpha oscillations also extend to the hand. Magnetoencephalography was used to evaluate event-related changes in the theta-alpha and beta (18-34 Hz) somatosensory cortical oscillations in groups of children with CP and typically developing (TD) children following tactile stimulation of their hands. Our results showed that the somatosensory theta-alpha oscillations were relatively intact in children with CP, which is in contrast to our previous results for foot tactile stimulations. We suspect that these inter-study differences may be related to the higher probability that the neural tracts serving the lower extremities are damaged in children with CP, compared to those serving the upper extremities. This inference is plausible since the participating children with CP had Manual Ability Classification System (MACS) levels between I and II. In contrast to the theta-alpha results, children with CP did exhibit a sharp increase in beta activity during the same time period, which was not observed in TD children. This suggests that children with CP still have deficits in the computational aspect of somatosensory processing.

  7. Vestibular-somatosensory convergence in head movement control during locomotion after long-duration space flight.

    PubMed

    Mulavara, A P; Ruttley, T; Cohen, H S; Peters, B T; Miller, C; Brady, R; Merkle, L; Bloomberg, J J

    2012-01-01

    Space flight causes astronauts to be exposed to adaptation in both the vestibular and body load-sensing somatosensory systems. The goal of these studies was to examine the contributions of vestibular and body load-sensing somatosensory influences on vestibular mediated head movement control during locomotion after long-duration space flight. Subjects walked on a motor driven treadmill while performing a gaze stabilization task. Data were collected from three independent subject groups that included bilateral labyrinthine deficient (LD) patients, normal subjects before and after 30 minutes of 40% bodyweight unloaded treadmill walking, and astronauts before and after long-duration space flight. Motion data from the head and trunk segments were used to calculate the amplitude of angular head pitch and trunk vertical translation movement while subjects performed a gaze stabilization task, to estimate the contributions of vestibular reflexive mechanisms in head pitch movements. Exposure to unloaded locomotion caused a significant increase in head pitch movements in normal subjects, whereas the head pitch movements of LD patients were significantly decreased. This is the first evidence of adaptation of vestibular mediated head movement responses to unloaded treadmill walking. Astronaut subjects showed a heterogeneous response of both increases and decreases in the amplitude of head pitch movement. We infer that body load-sensing somatosensory input centrally modulates vestibular input and can adaptively modify vestibularly mediated head-movement control during locomotion. Thus, space flight may cause central adaptation of the converging vestibular and body load-sensing somatosensory systems leading to alterations in head movement control.

  8. Cross-sectional imaging of functional activation in the rat somatosensory cortex with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Aguirre, A. D.; Chen, Y.; Ruvinskaya, L.; Devor, A.; Boas, D. A.; Fujimoto, J. G.

    2005-08-01

    Simultaneous optical coherence tomography (OCT) and video microscopy were performed on the rat somatosensory cortex through a thinned skull during forepaw stimulation. Fractional change measurements in OCT images reveal a functional signal timecourse similar to well understood hemodynamic signal timecourses measured with video microscopy. The precise etiology of the observed OCT functional signal is still under investigation, but these results suggest that OCT can provide high-resolution cross-sectional images of functional neuro-vascular activation.

  9. [The cervical somatosensory evoked potential in lesions of the cortical efferents].

    PubMed

    Strenge, H

    1990-03-01

    Cervical and cortical somatosensory evoked potentials to median nerve stimulation were analysed in 20 patients with unilateral central paresis of the arm. Neither the configuration nor the latency and amplitude measures of the neck potential did reveal any association with pathological alterations of cortical efferents or with abnormal cortically evoked responses. Thus, also in this population the evaluation of cervical potentials can be done according to the known criteria. PMID:2110891

  10. Cortical localization of phase and amplitude dynamics predicting access to somatosensory awareness.

    PubMed

    Hirvonen, Jonni; Palva, Satu

    2016-01-01

    Neural dynamics leading to conscious sensory perception have remained enigmatic in despite of large interest. Human functional magnetic resonance imaging (fMRI) studies have revealed that a co-activation of sensory and frontoparietal areas is crucial for conscious sensory perception in the several second time-scale of BOLD signal fluctuations. Electrophysiological recordings with magneto- and electroencephalography (MEG and EEG) and intracranial EEG (iEEG) have shown that event related responses (ERs), phase-locking of neuronal activity, and oscillation amplitude modulations in sub-second timescales are greater for consciously perceived than for unperceived stimuli. The cortical sources of ER and oscillation dynamics predicting the conscious perception have, however, remained unclear because these prior studies have utilized MEG/EEG sensor-level analyses or iEEG with limited neuroanatomical coverage. We used a somatosensory detection task, magnetoencephalography (MEG), and cortically constrained source reconstruction to identify the cortical areas where ERs, local poststimulus amplitudes and phase-locking of neuronal activity are predictive of the conscious access of somatosensory information. We show here that strengthened ERs, phase-locking to stimulus onset (SL), and induced oscillations amplitude modulations all predicted conscious somatosensory perception, but the most robust and widespread of these was SL that was sustained in low-alpha (6-10 Hz) band. The strength of SL and to a lesser extent that of ER predicted conscious perception in the somatosensory, lateral and medial frontal, posterior parietal, and in the cingulate cortex. These data suggest that a rapid phase-reorganization and concurrent oscillation amplitude modulations in these areas play an instrumental role in the emergence of a conscious percept.

  11. The importance of the negative blood-oxygenation-level-dependent (BOLD) response in the somatosensory cortex.

    PubMed

    Klingner, Carsten M; Brodoehl, Stefan; Witte, Otto W

    2015-01-01

    In recent years, multiple studies have shown task-induced negative blood-oxygenation-level-dependent responses (NBRs) in multiple brain regions in humans and animals. Converging evidence suggests that task-induced NBRs can be interpreted in terms of decreased neuronal activity. However, the vascular and metabolic dynamics and functional importance of the NBR are highly debated. Here, we review studies investigating the origin and functional importance of the NBR, with special attention to the somatosensory cortex. PMID:26057216

  12. Children with cerebral palsy have uncharacteristic somatosensory cortical oscillations after stimulation of the hand mechanoreceptors.

    PubMed

    Kurz, M J; Becker, K M; Heinrichs-Graham, E; Wilson, T W

    2015-10-01

    Numerous clinical investigations have reported that children with cerebral palsy (CP) have tactile discrimination deficits that likely limit their ability to plan and manipulate objects. Despite this clinical awareness, we still have a substantial knowledge gap in our understanding of the neurological basis for these tactile discrimination deficits. Previously, we have shown that children with CP have aberrant theta-alpha (4-14 Hz) oscillations in the somatosensory cortices following tactile stimulation of the foot. In this investigation, we evaluated if these aberrant theta-alpha oscillations also extend to the hand. Magnetoencephalography was used to evaluate event-related changes in the theta-alpha and beta (18-34 Hz) somatosensory cortical oscillations in groups of children with CP and typically developing (TD) children following tactile stimulation of their hands. Our results showed that the somatosensory theta-alpha oscillations were relatively intact in children with CP, which is in contrast to our previous results for foot tactile stimulations. We suspect that these inter-study differences may be related to the higher probability that the neural tracts serving the lower extremities are damaged in children with CP, compared to those serving the upper extremities. This inference is plausible since the participating children with CP had Manual Ability Classification System (MACS) levels between I and II. In contrast to the theta-alpha results, children with CP did exhibit a sharp increase in beta activity during the same time period, which was not observed in TD children. This suggests that children with CP still have deficits in the computational aspect of somatosensory processing. PMID:26235434

  13. Allergic Contact Dermatitis

    PubMed Central

    Nelson, Jenny L.

    2010-01-01

    Epicutaneous patch testing is the gold standard method for the diagnosis of allergic contact dermatitis. Despite this knowledge, many clinical dermatologists do not offer patch testing in their offices or offer testing with only a limited number of allergens. Introduced in 1995, the Thin-Layer Rapid Use Epicutaneous Test originally contained 23 allergens and one control. In 2007, five additional allergens were added. This United States Food and Drug Administration-approved patch testing system made patch testing more convenient, and after its introduction, more dermatologists offered patch testing services. However, the number of allergens in the Thin-Layer Rapid Use Epicutaneous Test remains relatively low. Every two years, the North American Contact Dermatitis Group collects and reports the data from patch testing among its members to a standardized series of allergens. In 2005-2006, the Group used a series of 65 allergens. Of the top 30 allergens reported in 2005-2006, 10 were not included in the Thin-Layer Rapid Use Epicutaneous Test. Knowledge of and testing for additional allergens such as these may increase patch testing yield. PMID:20967194

  14. Somatosensory brainstem, thalamus, and cortex of the California sea lion (Zalophus californianus).

    PubMed

    Sawyer, Eva K; Turner, Emily C; Kaas, Jon H

    2016-06-15

    Pinnipeds (sea lions, seals, and walruses) are notable for many reasons, including their ape-sized brains, their adaptation to a coastal niche that combines mastery of the sea with strong ties to land, and the remarkable abilities of their trigeminal whisker system. However, little is known about the central nervous system of pinnipeds. Here we report on the somatosensory areas of the nervous system of the California sea lion (Zalophus californianus). Using stains for Nissl, cytochrome oxidase, and vesicular glutamate transporters, we investigated the primary somatosensory areas in the brainstem, thalamus, and cortex in one sea lion pup and the external anatomy of the brain in a second pup. We find that the sea lion's impressive array of whiskers is matched by a large trigeminal representation in the brainstem with well-defined parcellation that resembles the barrelettes found in rodents but scaled upward in size. The dorsal column nuclei are large and distinct. The ventral posterior nucleus of the thalamus has divisions, with a large area for the presumptive head representation. Primary somatosensory cortex is located in the neocortex just anterior to the main vertical fissure, and precisely locating it as we do here is useful for comparing the highly gyrified pinniped cortex with that of other carnivores. To our knowledge this work is the first comprehensive report on the central nervous system areas for any sensory system in a pinniped. The results may be useful both in the veterinary setting and for comparative studies related to brain evolution. PMID:26878587

  15. Seeing Is Not Feeling: Posterior Parietal But Not Somatosensory Cortex Engagement During Touch Observation

    PubMed Central

    Baker, Chris I.

    2015-01-01

    Observing touch has been reported to elicit activation in human primary and secondary somatosensory cortices and is suggested to underlie our ability to interpret other's behavior and potentially empathy. However, despite these reports, there are a large number of inconsistencies in terms of the precise topography of activation, the extent of hemispheric lateralization, and what aspects of the stimulus are necessary to drive responses. To address these issues, we investigated the localization and functional properties of regions responsive to observed touch in a large group of participants (n = 40). Surprisingly, even with a lenient contrast of hand brushing versus brushing alone, we did not find any selective activation for observed touch in the hand regions of somatosensory cortex but rather in superior and inferior portions of neighboring posterior parietal cortex, predominantly in the left hemisphere. These regions in the posterior parietal cortex required the presence of both brush and hand to elicit strong responses and showed some selectivity for the form of the object or agent of touch. Furthermore, the inferior parietal region showed nonspecific tactile and motor responses, suggesting some similarity to area PFG in the monkey. Collectively, our findings challenge the automatic engagement of somatosensory cortex when observing touch, suggest mislocalization in previous studies, and instead highlight the role of posterior parietal cortex. PMID:25632124

  16. Early changes in somatosensory function in spinal pain: a systematic review and meta-analysis.

    PubMed

    Marcuzzi, Anna; Dean, Catherine M; Wrigley, Paul J; Hush, Julia M

    2015-02-01

    Alterations in sensory processing have been demonstrated in chronic low back and neck pain. However, it has not been yet systematically summarized how early these changes occur in spinal pain. This systematic review examines the available literature measuring somatosensory function in acute (<6 weeks) and subacute (6-12 weeks) spinal pain. The protocol for this review has been registered on the International Prospective Register of Systematic Reviews (PROSPERO). An electronic search of 4 databases was conducted to retrieve studies assessing somatosensory function by quantitative sensory testing in adults with spinal pain of up to 12 weeks duration. Two reviewers independently screened the studies and assessed the risk of bias. Studies were grouped according to spinal pain condition (whiplash injury, idiopathic neck pain, and nonspecific low back pain), and, where possible, meta-analyses were performed for comparable results. Fifteen studies were included. Sources of bias included lack of assessor blinding, unclear sampling methods, and lack of control for confounders. We found that: (1) there is consistent evidence for thermal and widespread mechanical pain hypersensitivity in the acute stage of whiplash, (2) there is no evidence for pain hypersensitivity in the acute and subacute stage of idiopathic neck pain, although the body of evidence is small, and (3) hyperalgesia and spinal cord hyperexcitability have been detected in early stages of nonspecific low back pain, although evidence about widespread effects are conflicting. Future longitudinal research using multiple sensory modalities and standardized testing may reveal the involvement of somatosensory changes in the development and maintenance of chronic pain.

  17. The impact of eye closure on somatosensory perception in the elderly.

    PubMed

    Brodoehl, Stefan; Klingner, Carsten; Stieglitz, Katharina; Witte, Otto W

    2015-10-15

    Visual dominance over other senses is a well-known phenomenon. Closing the eyes, even in complete darkness, can improve somatosensory perception by switching off various aspects of visual dominance. How and if this mechanism is affected by aging remains unknown. We performed detailed neurophysiological and functional MR-imaging on healthy young and elderly participants under the conditions of opened and closed eyes. We found an improved perception threshold in both groups when the eyes were closed, but the improvement was significantly less pronounced in the elderly. fMRI data revealed increased resting activity in the somatosensory cortex with closed eyes, and the stimulus-induced activity of the secondary somatosensory cortex decreased in the young but not in the elderly. This study demonstrates that a switch towards unisensory processing via eye closure is preserved but significantly reduced in the aging brain. We suggest that the decreased ability for unisensory processing is a general phenomenon in the aging brain resulting in a shift toward multisensory integration.

  18. The separation of overlapping neuromagnetic sources in first and second somatosensory cortices.

    PubMed

    Elbert, T; Junghöfer, M; Scholz, B; Schneider, S

    1995-01-01

    In response to a somatosensory stimulus, two cortical centers in each hemisphere produce neural mass activity large enough to be detected with electric (EEG) or magnetic (MEG) measurements. Both the primary somatosensory cortex (S-I), located in the postcentral sulcus and in the depths of the central sulcus, as well as the secondary somatic sensory cortex (S-II), lying in the upper bank of the Sylvian fissure, respond within the first 100 ms such that the two activities overlap in time. We demonstrate that this overlap can be disentangled using a MUSIC-type approach, as suggested by Oppelt and Scholz. It needs no a priori information about the sources. As the results show, there are several instances in time in which only one of the two centers (SI, SII) is active. It is only for these time segments that a single moving dipole yields meaningful results. Such time intervals occur during the upstroke of the late component around 60 ms (only SI activity) and during the down-stroke around 120 ms (only SII activity). In these time intervals the activity of one of the somatosensory areas is still large enough, while the other center is not yet or is no longer active.

  19. The roles of primary somatosensory cortex in the coding of pain

    PubMed Central

    Vierck, Charles J.; Whitsel, Barry L.; Favorov, Oleg V.; Brown, Alexander W.; Tommerdahl, Mark

    2014-01-01

    The intensity and submodality of pain are widely attributed to stimulus encoding by peripheral and subcortical spinal/trigeminal portions of the somatosensory nervous system. Consistent with this interpretation are studies of surgically anesthetized animals, showing that relationships between nociceptive stimulation and activation of neurons are similar at subcortical levels of somatosensory projection and within the primary somatosensory cortex (in cytoarchitectural areas 3b and 1 of SI). Such findings have led to characterizations of SI as a network which preserves, rather than transforms, the excitatory drive it receives from subcortical levels. Inconsistent with this perspective are images and neurophysiological recordings of SI neurons in lightly anesthetized primates. These studies show that an extreme anterior position within SI (area 3a) receives input originating predominantly from unmyelinated nociceptors, distinguishing it from posterior SI (areas 3b and 1), long recognized as receiving input predominantly from myelinated afferents, including nociceptors. Of particular importance, interactions between these subregions during maintained nociceptive stimulation are accompanied by an altered SI response to myelinated and unmyelinated nociceptors. A revised view of pain coding within SI cortex is discussed, and potentially significant clinical implications are emphasized. PMID:23245864

  20. Topographic representation of vestibular and somatosensory signals in the anuran thalamus.

    PubMed

    Westhoff, G; Roth, G; Straka, H

    2004-01-01

    In the isolated brain of the fire-bellied toad, Bombina orientalis, the spatial distribution of vestibular and somatosensory responses in thalamic nuclei was studied following electrical activation of the Vth nerve, the ramus anterior of the VIIIth nerve and of the dorsal roots of spinal nerves 3 and 8. Responses were systematically mapped in frontal planes through the diencephalon at four rostro-caudal levels. The calculated activity maps were superimposed on the outlines of diencephalic nuclei, and those nuclei that received particularly large inputs from the stimulated sensory nerve roots were indicated. Maximal response amplitudes coincided with ventral, central, and posterior thalamic areas and exhibited a topography that differed for each sensory nerve root. Maximal responses evoked from the Vth nerve were largely separated from those from spinal dorsal roots 3 and 8, whereas maximal vestibular responses partly overlapped with those from the other somatosensory nerve roots. Our findings indicate that within the amphibian thalamus sensory signals originating from different nerve roots are largely represented in separate areas as is the case in the thalamus of amniotes. However, the anterior dorsal thalamus which is the only origin of ascending pathways to the medial and dorsal pallium (assumed homologues of the mammalian hippocampus and neocortex, respectively) receives only minor vestibular and somatosensory input. This corroborates the view that amphibians lack a direct sensory thalamo-cortical, or "lemnothalamic," pathway typical of mammals and birds.

  1. Development of somatosensory perception in children: a longitudinal QST-study.

    PubMed

    Hirschfeld, Gerrit; Zernikow, Boris; Kraemer, Nicole; Hechler, Tanja; Aksu, Fuat; Krumova, Elena; Maier, Christoph; Magerl, Walter; Blankenburg, Markus

    2012-02-01

    Cross-sectional studies on somatosensory perception in children demonstrate lower pain thresholds for children compared with adolescents. The aim of the present longitudinal study was to replicate these age-related differences in a longitudinal design. Total 38 children and adolescents aged 6 to 16 years (two girls and two boys within each year) participated in this study. Quantitative sensory testing (QST) according to the protocol of the German research network on neuropathic pain (DFNS) was assessed twice with an interval of 15.8 ± 3.0 months. Bland-Altman analyses describe the short-term reliability of the measurements. Intraindividual sensory development was measured using paired t-test and quantified by effect sizes Cohen's d between the two measurements. QST parameters showed good short-term reliability. Over a period of 1 year, children became less sensitive to painful stimuli, especially to cold pain, pressure pain, and mechanical pain. No systematic developmental changes were observed in response to the other somatosensory stimuli. QST is reliable over short retest intervals. In line with previous results from cross-sectional studies, we find a decrease in pain sensitivity with increasing age but no differences in nonnociceptive somatosensory processing over a period of 1 year in children between 6 and 16 years of age. Taken together, these results highlight the importance of a reference-based interpretation of the individual QST data.

  2. Image-Guided Transcranial Focused Ultrasound Stimulates Human Primary Somatosensory Cortex

    NASA Astrophysics Data System (ADS)

    Lee, Wonhye; Kim, Hyungmin; Jung, Yujin; Song, In-Uk; Chung, Yong An; Yoo, Seung-Schik

    2015-03-01

    Focused ultrasound (FUS) has recently been investigated as a new mode of non-invasive brain stimulation, which offers exquisite spatial resolution and depth control. We report on the elicitation of explicit somatosensory sensations as well as accompanying evoked electroencephalographic (EEG) potentials induced by FUS stimulation of the human somatosensory cortex. As guided by individual-specific neuroimage data, FUS was transcranially delivered to the hand somatosensory cortex among healthy volunteers. The sonication elicited transient tactile sensations on the hand area contralateral to the sonicated hemisphere, with anatomical specificity of up to a finger, while EEG recordings revealed the elicitation of sonication-specific evoked potentials. Retrospective numerical simulation of the acoustic propagation through the skull showed that a threshold of acoustic intensity may exist for successful cortical stimulation. The neurological and neuroradiological assessment before and after the sonication, along with strict safety considerations through the individual-specific estimation of effective acoustic intensity in situ and thermal effects, showed promising initial safety profile; however, equal/more rigorous precautionary procedures are advised for future studies. The transient and localized stimulation of the brain using image-guided transcranial FUS may serve as a novel tool for the non-invasive assessment and modification of region-specific brain function.

  3. Asymmetric Multisensory Interactions of Visual and Somatosensory Responses in a Region of the Rat Parietal Cortex

    PubMed Central

    Lippert, Michael T.; Takagaki, Kentaroh

    2013-01-01

    Perception greatly benefits from integrating multiple sensory cues into a unified percept. To study the neural mechanisms of sensory integration, model systems are required that allow the simultaneous assessment of activity and the use of techniques to affect individual neural processes in behaving animals. While rodents qualify for these requirements, little is known about multisensory integration and areas involved for this purpose in the rodent. Using optical imaging combined with laminar electrophysiological recordings, the rat parietal cortex was identified as an area where visual and somatosensory inputs converge and interact. Our results reveal similar response patterns to visual and somatosensory stimuli at the level of current source density (CSD) responses and multi-unit responses within a strip in parietal cortex. Surprisingly, a selective asymmetry was observed in multisensory interactions: when the somatosensory response preceded the visual response, supra-linear summation of CSD was observed, but the reverse stimulus order resulted in sub-linear effects in the CSD. This asymmetry was not present in multi-unit activity however, which showed consistently sub-linear interactions. These interactions were restricted to a specific temporal window, and pharmacological tests revealed significant local intra-cortical contributions to this phenomenon. Our results highlight the rodent parietal cortex as a system to model the neural underpinnings of multisensory processing in behaving animals and at the cellular level. PMID:23667650

  4. Image-Guided Transcranial Focused Ultrasound Stimulates Human Primary Somatosensory Cortex

    PubMed Central

    Lee, Wonhye; Kim, Hyungmin; Jung, Yujin; Song, In-Uk; Chung, Yong An; Yoo, Seung-Schik

    2015-01-01

    Focused ultrasound (FUS) has recently been investigated as a new mode of non-invasive brain stimulation, which offers exquisite spatial resolution and depth control. We report on the elicitation of explicit somatosensory sensations as well as accompanying evoked electroencephalographic (EEG) potentials induced by FUS stimulation of the human somatosensory cortex. As guided by individual-specific neuroimage data, FUS was transcranially delivered to the hand somatosensory cortex among healthy volunteers. The sonication elicited transient tactile sensations on the hand area contralateral to the sonicated hemisphere, with anatomical specificity of up to a finger, while EEG recordings revealed the elicitation of sonication-specific evoked potentials. Retrospective numerical simulation of the acoustic propagation through the skull showed that a threshold of acoustic intensity may exist for successful cortical stimulation. The neurological and neuroradiological assessment before and after the sonication, along with strict safety considerations through the individual-specific estimation of effective acoustic intensity in situ and thermal effects, showed promising initial safety profile; however, equal/more rigorous precautionary procedures are advised for future studies. The transient and localized stimulation of the brain using image-guided transcranial FUS may serve as a novel tool for the non-invasive assessment and modification of region-specific brain function. PMID:25735418

  5. Effect of Range and Angular Velocity of Passive Movement on Somatosensory Evoked Magnetic Fields.

    PubMed

    Sugawara, Kazuhiro; Onishi, Hideaki; Yamashiro, Koya; Kojima, Sho; Miyaguchi, Shota; Kotan, Shinichi; Tsubaki, Atsuhiro; Kirimoto, Hikari; Tamaki, Hiroyuki; Shirozu, Hiroshi; Kameyama, Shigeki

    2016-09-01

    To clarify characteristics of each human somatosensory evoked field (SEF) component following passive movement (PM), PM1, PM2, and PM3, using high spatiotemporal resolution 306-channel magnetoencephalography and varying PM range and angular velocity. We recorded SEFs following PM under three conditions [normal range-normal velocity (NN), small range-normal velocity (SN), and small range-slow velocity (SS)] with changing movement range and angular velocity in 12 participants and calculated the amplitude, equivalent current dipole (ECD) location, and the ECD strength for each component. All components were observed in six participants, whereas only PM1 and PM3 in the other six. Clear response deflections at the ipsilateral hemisphere to PM side were observed in seven participants. PM1 amplitude was larger under NN and SN conditions, and mean ECD location for PM1 was at primary motor area. PM3 amplitude was larger under SN condition and mean ECD location for PM3 under SS condition was at primary somatosensory area. PM1 amplitude was dependent on the angular velocity of PM, suggesting that PM1 reflects afferent input from muscle spindle, whereas PM3 amplitude was dependent on the duration. The ECD for PM3 was located in the primary somatosensory cortex, suggesting that PM3 reflects cutaneous input. We confirmed the hypothesis for locally distinct generators and characteristics of each SEF component.

  6. Amplitude and timing of somatosensory cortex activity in Task Specific Focal Hand Dystonia

    PubMed Central

    Dolberg, Rebecca; Hinkley, Leighton B. N.; Honma, Susanne; Zhu, Zhao; Findlay, Anne M.; Byl, Nancy N.; Nagarjan, Srikantan S.

    2011-01-01

    Objective Task-specific focal hand dystonia (tspFHD) is a movement disorder diagnosed in individuals performing repetitive hand behaviors. The extent to which processing anomalies in primary sensory cortex extend to other regions or across the two hemispheres is presently unclear. Methods In response to low/high rate and novel tactile stimuli on the affected and unaffected hands, magnetoencephalography (MEG) was used to elaborate activity timing and amplitude in the primary somatosensory (S1) and secondary somatosensory/parietal ventral (S2/PV) cortices. MEG and clinical performance measures were collected from thirteen patients and matched controls. Results Compared to controls, subjects with tspFHD had increased response amplitude in S2/PV bilaterally in response to high rate and novel stimuli. Subjects with tspFHD also showed increased response latency (low rate, novel) of the affected digits in contralateral S1. For high rate, subjects with tspFHD showed increased response latency in ipsilateral S1 and S2/PV bilaterally. Activation differences correlated with functional sensory deficits (predicting a latency shift in S1), motor speed and muscle strength. Conclusions There are objective differences in the amplitude and timing of activity for both hands across contralateral and ipsilateral somatosensory cortex in patients with tspFHD. Significance Knowledge of cortical processing abnormalities across S1 and S2/PV in dystonia should be applied towards the development of learning based sensorimotor interventions. PMID:21802357

  7. Somatosensory profiling of intra-oral capsaicin and menthol in healthy subjects.

    PubMed

    Lu, Shengyi; Baad-Hansen, Lene; List, Thomas; Zhang, Zhenting; Svensson, Peter

    2013-02-01

    This study was designed to investigate the effect of surrogate orofacial pain models on the quantitative sensory testing (QST) profile in healthy participants. Capsaicin, menthol, or saline (control) were applied topically onto the gingiva of 15 healthy subjects for 15 min. During application, the subjects rated pain intensity on a score of 0-10, on an electronic visual analog scale (VAS). A standardized intra-oral QST protocol was performed before and immediately after application. Data obtained before and after application were compared using rank-sum tests, and QST profiles were made after Z-transformation. Application of capsaicin caused moderate levels of pain (VAS(peak)  = 6.0 ± 0.7), and application of menthol produced mild levels of pain (VAS(peak)  = 1.8 ± 0.6). Capsaicin induced hypersensitivity to warmth, heat pain and cold pain and hyposensitivity to mechanical stimuli. Menthol induced hypersensitivity to cold and warmth. Saline caused hypersensitivity to heat pain and hyposensitivity to mechanical stimuli. However, somatosensory profiles from Z-scores demonstrated sensory gains regarding warmth detection and heat pain only after application of capsaicin. In conclusion, a standardized battery of QST showed somatosensory changes after application of capsaicin, menthol and saline to the gingiva. However, the Z-score-based profiles may only reflect the most prominent somatosensory changes and thus represent a conservative approach for evaluation of data. PMID:23331421

  8. Skill-specific changes in somatosensory-evoked potentials and reaction times in baseball players.

    PubMed

    Yamashiro, Koya; Sato, Daisuke; Onishi, Hideaki; Yoshida, Takuya; Horiuchi, Yoko; Nakazawa, Sho; Maruyama, Atsuo

    2013-03-01

    Athletic training is known to induce neuroplastic alterations in specific somatosensory circuits, which are reflected by changes in short-latency somatosensory-evoked potentials (SEPs). The aim of this study is to clarify whether specific training in athletes affects the long-latency SEPs related to information processing of stimulation. The long-latency SEPs P100 and N140 were recorded at midline cortical electrode positions (Fz, Cz, and Pz) in response to stimulation of the index finger of the dominant hand in fifteen baseball players (baseball group) and in fifteen athletes in sports such as swimming, track and field events, and soccer (sports group) that do not require fine somatosensory discrimination or motor control of the hand. The long-latency SEPs were measured under a passive condition (no response required) and a reaction time (RT) condition in which subjects were instructed to rapidly push a button in response to stimulus presentation. The peak P100 and peak N140 latencies and RT were significantly shorter in the baseball group than the sports group. Moreover, there were significant positive correlations between RT and both the peak P100 and the peak N140 latencies. Specific athletic training regimens that involve the hand may induce neuroplastic alterations in the cortical hand representation areas playing a vital role in rapid sensory processing and initiation of motor responses.

  9. Somatosensory brainstem, thalamus, and cortex of the California sea lion (Zalophus californianus).

    PubMed

    Sawyer, Eva K; Turner, Emily C; Kaas, Jon H

    2016-06-15

    Pinnipeds (sea lions, seals, and walruses) are notable for many reasons, including their ape-sized brains, their adaptation to a coastal niche that combines mastery of the sea with strong ties to land, and the remarkable abilities of their trigeminal whisker system. However, little is known about the central nervous system of pinnipeds. Here we report on the somatosensory areas of the nervous system of the California sea lion (Zalophus californianus). Using stains for Nissl, cytochrome oxidase, and vesicular glutamate transporters, we investigated the primary somatosensory areas in the brainstem, thalamus, and cortex in one sea lion pup and the external anatomy of the brain in a second pup. We find that the sea lion's impressive array of whiskers is matched by a large trigeminal representation in the brainstem with well-defined parcellation that resembles the barrelettes found in rodents but scaled upward in size. The dorsal column nuclei are large and distinct. The ventral posterior nucleus of the thalamus has divisions, with a large area for the presumptive head representation. Primary somatosensory cortex is located in the neocortex just anterior to the main vertical fissure, and precisely locating it as we do here is useful for comparing the highly gyrified pinniped cortex with that of other carnivores. To our knowledge this work is the first comprehensive report on the central nervous system areas for any sensory system in a pinniped. The results may be useful both in the veterinary setting and for comparative studies related to brain evolution.

  10. The State-of-the-Science on Somatosensory Function and Its Impact on Daily Life in Adults and Older Adults, and Following Stroke: A Scoping Review.

    PubMed

    Carey, Leeanne M; Lamp, Gemma; Turville, Megan

    2016-04-01

    The aim was to identify and synthesize research evidence about how adults and older adults process somatosensory information in daily activities, and the interventions available to regain somatosensory function following stroke. We developed two interacting concept maps to address the research questions. The scoping review was conducted from 2005 to 2015 across Web of Science, AMED, CINAHL, Embase, Medline, and PsychInfo databases. Search terms included somatosensory, perception, performance, participation, older adult, stroke, intervention, discrimination, learning, and neuroplasticity. Contributions from 103 articles for Concept 1 and 14 articles for Concept 2 are reported. Measures of somatosensory processing, performance, and participation used are identified. Interventions available to treat somatosensory loss are summarized in relation to approach, outcome measures, and theory/mechanisms underlying. A gap exists in the current understanding of how somatosensory function affects the daily lives of adults. A multidisciplinary approach that includes performance and participation outcomes is recommended to advance the field.

  11. The State-of-the-Science on Somatosensory Function and Its Impact on Daily Life in Adults and Older Adults, and Following Stroke: A Scoping Review.

    PubMed

    Carey, Leeanne M; Lamp, Gemma; Turville, Megan

    2016-04-01

    The aim was to identify and synthesize research evidence about how adults and older adults process somatosensory information in daily activities, and the interventions available to regain somatosensory function following stroke. We developed two interacting concept maps to address the research questions. The scoping review was conducted from 2005 to 2015 across Web of Science, AMED, CINAHL, Embase, Medline, and PsychInfo databases. Search terms included somatosensory, perception, performance, participation, older adult, stroke, intervention, discrimination, learning, and neuroplasticity. Contributions from 103 articles for Concept 1 and 14 articles for Concept 2 are reported. Measures of somatosensory processing, performance, and participation used are identified. Interventions available to treat somatosensory loss are summarized in relation to approach, outcome measures, and theory/mechanisms underlying. A gap exists in the current understanding of how somatosensory function affects the daily lives of adults. A multidisciplinary approach that includes performance and participation outcomes is recommended to advance the field. PMID:27504989

  12. Protein Residue Contacts and Prediction Methods

    PubMed Central

    Adhikari, Badri

    2016-01-01

    In the field of computational structural proteomics, contact predictions have shown new prospects of solving the longstanding problem of ab initio protein structure prediction. In the last few years, application of deep learning algorithms and availability of large protein sequence databases, combined with improvement in methods that derive contacts from multiple sequence alignments, have shown a huge increase in the precision of contact prediction. In addition, these predicted contacts have also been used to build three-dimensional models from scratch. In this chapter, we briefly discuss many elements of protein residue–residue contacts and the methods available for prediction, focusing on a state-of-the-art contact prediction tool, DNcon. Illustrating with a case study, we describe how DNcon can be used to make ab initio contact predictions for a given protein sequence and discuss how the predicted contacts may be analyzed and evaluated. PMID:27115648

  13. Contact Dermatitis in Pediatrics.

    PubMed

    Pelletier, Janice L; Perez, Caroline; Jacob, Sharon E

    2016-08-01

    Contact dermatitis is an umbrella term that describes the skin's reaction to contacted noxious or allergenic substances. The two main categories of contact dermatitis are irritant type and allergic type. This review discusses the signs, symptoms, causes, and complications of contact dermatitis. It addresses the testing, treatment, and prevention of contact dermatitis. Proper management of contact dermatitis includes avoidance measures for susceptible children. Implementation of a nickel directive (regulating the use of nickel in jewelry and other products that come into contact with the skin) could further reduce exposure to the most common allergens in the pediatric population. [Pediatr Ann. 2016;45(8):e287-e292.]. PMID:27517356

  14. Attention and visual interference stimulation affect somatosensory processing: a magnetoencephalographic study.

    PubMed

    Lam, K; Kakigi, R; Mukai, T; Yamasaki, H

    2001-01-01

    In our previous study, continuous visual (cartoon and random dot motion) and auditory (music) stimulation changed the somatosensory evoked magnetic fields following electrical stimulation of the median nerve in human subjects. They enhanced the middle-latency components (3M and 4M) generated in the contralateral primary somatosensory cortex, and reduced the MI component generated in the ipsilateral secondary somatosensory cortex. We speculated that such interference effects were caused by activation of polymodal neurons in areas 5 and/or 7 of the parietal lobe as well as in the medial superior temporal region and superior temporal sulcus. However, we could not exclude the effect of attention on such interference effects. In the present study, to know the effect of attention on visual and auditory interference in these changes, we stimulated the bilateral median nerves unilaterally in a random order, and asked subjects to count the number of times the left median nerve was stimulated while visual or auditory interference was applied. Five components (1M-5M) were identified in the hemisphere contralateral to the stimulated nerve and only one component (MI) was found in the ipsilateral hemisphere. The 3M and 4M components (33-75 ms in latency) were enhanced by both attention and visual interference stimulation but not by auditory stimulation. The 5M component (70-115 ms) and MI component (70-133 ms) were enhanced by attention, but were not changed by attention together with visual or auditory interference. Summarizing the results of our previous study and the present study, (1) visual interference alone enhanced the 3M and 4M but reduced the MI, and (2) attention alone also enhanced the 3M and 4M, and enhanced the 5M and MI. As a result, (3) visual interference with attention enhanced the 3M and 4M more, and showed no significant change of the 5M and MI. This was compatible with a summation of the effects caused by visual interference alone and attention alone, but

  15. CORRIGENDUM: Multiscale electrical contact resistance in clustered contact distribution Multiscale electrical contact resistance in clustered contact distribution

    NASA Astrophysics Data System (ADS)

    Lee, Sangyoung; Cho, Hyun; Jang, Yong Hoon

    2010-06-01

    The authors wish to explain the similarity between some figures in the above paper (hereafter called the JPD paper) and in their other publication, Lee S, Jang Y H and Kim W 2008 Effects of nanosized contact spots on thermal contact resistance J. Appl. Phys.103 074308 (hereafter called the JAP paper), and to explain the differences between the two papers, which are not explicitly stated in the JPD paper. The main objective of the JAP paper is to calculate the thermal contact resistance of the nanosized contact spots in multiscale contact. During the process of multiscale analysis, the thermal conductivity varies, especially below the phonon mean free path. The JPD paper deals with the electrical contact resistance in the multiscale contact distribution with an assumption of constant electrical resistivity, which is known as a different kind of physics in a larger characteristic length scale. There are similar figures in the JPD paper and the JAP paper: figures 6, 7 and 8 in the JPD paper and figures 3, 4 and 5 in the JAP paper. Two research works were performed on the basis of a specific microcontact distribution. In the JAP paper, the scale of the contact distribution is in the range of the phonon mean free path of Si, which is a very small size of contact distribution. In the JPD paper, the scale of contact distribution is in the continuum scale, which is larger than the phonon mean free path. In addition, due to the characteristics of a fractal surface which repeatedly generates a similar shape of contact distribution in the different length scales, the shape of contact distribution looks similar, but the total sizes of domain in the JPD and JAP figures are different. The projected areas L × L of fractal surface of the JAP paper and JPD paper are 10 μm × 10 μm and 10 mm × 10 mm, respectively. The length scale is already stated in the JAP paper, but not in the JPD paper. Thus, we have to state that the figures were adapted from the JAP paper without clear

  16. Corticofugal projections induce long-lasting effects on somatosensory responses in the trigeminal complex of the rat

    PubMed Central

    Malmierca, Eduardo; Chaves-Coira, Irene; Rodrigo-Angulo, Margarita; Nuñez, Angel

    2014-01-01

    The sensory information flow at subcortical relay stations is controlled by the action of topographic connections from the neocortex. To determinate the functional properties of the somatosensory corticofugal projections to the principal (Pr5) and caudal spinal (Sp5C) trigeminal nuclei, we performed unitary recordings in anesthetized rats. To examine the effect of these cortical projections we used tactile stimulation of the whisker and electrical stimulation of somatosensory cortices. Corticofugal anatomical projections to Pr5 and Sp5C nuclei were detected by using retrograde fluorescent tracers. Neurons projecting exclusively to Pr5 were located in the cingulate cortex while neurons projecting to both Sp5C and Pr5 nuclei were located in the somatosensory and insular cortices (>75% of neurons). Physiological results indicated that primary somatosensory cortex produced a short-lasting facilitating or inhibiting effects (<5 min) of tactile responses in Pr5 nucleus through activation of NMDA glutamatergic or GABAA receptors since effects were blocked by iontophoretically application of APV and bicuculline, respectively. In contrast, stimulation of secondary somatosensory cortex did not affect most of the Pr5 neurons; however both cortices inhibited the nociceptive responses in the Sp5C nucleus through activation of glycinergic or GABAA receptors because effects were blocked by iontophoretically application of strychnine and bicuculline, respectively. These and anatomical results demonstrated that the somatosensory cortices projects to Pr5 nucleus to modulate tactile responses by excitatory and inhibitory actions, while projections to the Sp5C nucleus control nociceptive sensory transmission by only inhibitory effects. Thus, somatosensory cortices may modulate innocuous and noxious inputs simultaneously, contributing to the perception of specifically tactile or painful sensations. PMID:24904321

  17. The neural dynamics of somatosensory processing and adaptation across childhood: a high-density electrical mapping study.

    PubMed

    Uppal, Neha; Foxe, John J; Butler, John S; Acluche, Frantzy; Molholm, Sophie

    2016-03-01

    Young children are often hyperreactive to somatosensory inputs hardly noticed by adults, as exemplified by irritation to seams or labels in clothing. The neurodevelopmental mechanisms underlying changes in sensory reactivity are not well understood. Based on the idea that neurodevelopmental changes in somatosensory processing and/or changes in sensory adaptation might underlie developmental differences in somatosensory reactivity, high-density electroencephalography was used to examine how the nervous system responds and adapts to repeated vibrotactile stimulation over childhood. Participants aged 6-18 yr old were presented with 50-ms vibrotactile stimuli to the right wrist over the median nerve at 5 blocked interstimulus intervals (ranging from ∼7 to ∼1 stimulus per second). Somatosensory evoked potentials (SEPs) revealed three major phases of activation within the first 200 ms, with scalp topographies suggestive of neural generators in contralateral somatosensory cortex. Although overall SEPs were highly similar for younger, middle, and older age groups (6.1-9.8, 10.0-12.9, and 13.0-17.8 yr old), there were significant age-related amplitude differences in initial and later phases of the SEP. In contrast, robust adaptation effects for fast vs. slow presentation rates were observed that did not differ as a function of age. A greater amplitude response in the later portion of the SEP was observed for the youngest group and may be related to developmental changes in responsivity to somatosensory stimuli. These data suggest the protracted development of the somatosensory system over childhood, whereas adaptation, as assayed in this study, is largely in place by ∼7 yr of age. PMID:26763781

  18. Physical Exercise Preserves Adult Visual Plasticity in Mice and Restores it after a Stroke in the Somatosensory Cortex

    PubMed Central

    Kalogeraki, Evgenia; Pielecka-Fortuna, Justyna; Hüppe, Janika M.; Löwel, Siegrid

    2016-01-01

    The primary visual cortex (V1) is widely used to study brain plasticity, which is not only crucial for normal brain function, such as learning and memory, but also for recovery after brain injuries such as stroke. In standard cage (SC) raised mice, experience-dependent ocular dominance (OD) plasticity in V1 declines with age and is compromised by a lesion in adjacent and distant cortical regions. In contrast, mice raised in an enriched environment (EE), exhibit lifelong OD plasticity and are protected from losing OD plasticity after a stroke-lesion in the somatosensory cortex. Since SC mice with an access to a running wheel (RW) displayed preserved OD plasticity during aging, we investigated whether physical exercise might also provide a plasticity promoting effect after a cortical stroke. To this end, we tested if adult RW-raised mice preserved OD plasticity after stroke and also if short-term running after stroke restored OD plasticity to SC mice. Indeed, unlike mice without a RW, adult RW mice continued to show OD plasticity even after stroke, and a 2 weeks RW experience after stroke already restored lost OD plasticity. Additionally, the experience-enabled increase of the spatial frequency and contrast threshold of the optomotor reflex of the open eye, normally lost after a stroke, was restored in both groups of RW mice. Our data suggest that physical exercise alone can not only preserve visual plasticity into old age, but also restore it after a cortical stroke. PMID:27708575

  19. Early and moderate sensory stimulation exerts a protective effect on perilesion representations of somatosensory cortex after focal ischemic damage.

    PubMed

    Xerri, Christian; Zennou-Azogui, Yoh'i

    2014-01-01

    Previous studies have shown that intensive training within an early critical time window after focal cortical ischemia increases the area of damaged tissue and is detrimental to behavioral recovery. We postulated that moderate stimulation initiated soon after the lesion could have protective effects on peri-infarct cortical somatotopic representations. Therefore, we have assessed the effects of mild cutaneous stimulation delivered in an attention-demanding behavioral context on the functional organization of the perilesion somatosensory cortex using high-density electrophysiological mapping. We compared the effects of 6-day training initiated on the 3rd day postlesion (early training; ET) to those of same-duration training started on the 8th day (delayed training; DT). Our findings confirm previous work showing that the absence of training aggravates representational loss in the perilesion zone. In addition, ET was found to be sufficient to limit expansion of the ischemic lesion and reduce tissue loss, and substantially maintain the neuronal responsiveness to tactile stimulation, thereby preserving somatotopic map arrangement in the peri-infarct cortical territories. By contrast, DT did not prevent tissue loss and only partially reinstated lost representations in a use-dependent manner within the spared peri-infarct cortical area. This study differentiates the effects of early versus delayed training on perilesion tissue and cortical map reorganization, and underscores the neuroprotective influence of mild rehabilitative stimulation on neuronal response properties in the peri-infarct cortex during an early critical period. PMID:24914807

  20. Representation of Afferent Signals from Forearm Muscle and Cutaneous Nerves in the Primary Somatosensory Cortex of the Macaque Monkey

    PubMed Central

    Yamada, Hiroshi; Yaguchi, Hiroaki; Tomatsu, Saeka; Takei, Tomohiko; Oya, Tomomichi

    2016-01-01

    Proprioception is one’s overall sense of the relative positions and movements of the various parts of one’s body. The primary somatosensory cortex (SI) is involved in generating the proprioception by receiving peripheral sensory inputs from both cutaneous and muscle afferents. In particular, area 3a receives input from muscle afferents and areas 3b and 1 from cutaneous afferents. However, segregation of two sensory inputs to these cortical areas has not been evaluated quantitatively because of methodological difficulties in distinguishing the incoming signals. To overcome this, we applied electrical stimulation separately to two forearm nerves innervating muscle (deep radial nerve) and skin (superficial radial nerve), and examined the spatiotemporal distribution of sensory evoked potentials (SEPs) in SI of anaesthetized macaques. The SEPs arising from the deep radial nerve were observed exclusively at the bottom of central sulcus (CS), which was identified as area 3a using histological reconstruction. In contrast, SEPs evoked by stimulation of the superficial radial nerve were observed in the superficial part of SI, identified as areas 3b and 1. In addition to these earlier, larger potentials, we also found small and slightly delayed SEPs evoked by cutaneous nerve stimulation in area 3a. Coexistence of the SEPs from both deep and superficial radial nerves suggests that area 3a could integrate muscle and cutaneous signals to shape proprioception. PMID:27701434

  1. [Systemic contact dermatitis].

    PubMed

    Nowak, Daria; Gomułka, Krzysztof; Dziemieszonek, Paulina; Panaszek, Bernard

    2016-01-01

    Systemic contact dermatitis (SCD) is a skin inflammation occurring in a patient after systemic administration of a hapten, which previously caused an allergic contact skin reaction in the same person. Most frequently, hypersensitivity reactions typical for SCD occur after absorption of haptens with food or inhalation. Haptens occur mainly in the forms of metals and compounds present in natural resins, preservatives, food thickeners, flavorings and medicines. For many years, several studies have been conducted on understanding the pathogenesis of SCD in which both delayed type hypersensitivity (type IV) and immediate type I are observed. Components of the complement system are also suspected to attend there. Helper T cells (Th) (Th1 and Th2), cytotoxic T lymphocytes (Tc), and NK cells play a crucial role in the pathogenesis of SCD. They secrete a number of pro-inflammatory cytokines. In addition, regulatory T cells (Tregs) have an important role. They control and inhibit activity of the immune system during inflammation. Tregs release suppressor cytokines and interact directly with a target cell through presentation of immunosuppressive particles at the cell surface. Diagnostic methods are generally the patch test, oral provocation test, elimination diet and lymphocyte stimulation test. There are many kinds of inflammatory skin reactions caused by systemic haptens' distribution. They are manifested in a variety of clinical phenotypes of the disease. PMID:26943310

  2. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  3. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  4. Update on contact lithotripsy.

    PubMed

    Michel, M S; Köhrmann, K U; Alken, P

    2000-11-01

    Despite the development of extracorporeal shockwave lithotripsy, endoscopic stone removal, with or without intracorporeal lithotripsy, is still an effective minimally invasive alternative for special indications. There is no defined all-purpose lithotripsy procedure for contact lithotripsy. The choice of the lithotripsy procedure for endoscopic stone disintegration depends on a number of different factors, the main one being stone localization. Small calibre, flexible probes (electrohydraulic, pneumatic, laser) are especially appropriate for ureterorenoscopy, but the speed of stone disintegration is a limiting factor. In contrast, large calibre rigid probes (ultrasound) are clearly more effective, but are unsuitable in size for flexible ureterorenoscopy. This indicates that the type and size of the endoscope decisively influences the choice of devices for endoscopic stone disintegration. Additional inhibiting factors are the flexibility or the rigidity of the instrument and the diameter of the working channel. It must be noted that total costs are not only calculated on the purchase of the equipment, but must also cover disposable materials.

  5. Somatosensory processing and schizophrenia liability: proprioception, exteroceptive sensitivity, and graphesthesia performance in the biological relatives of schizophrenia patients.

    PubMed

    Chang, Bernard P; Lenzenweger, Mark F

    2005-02-01

    In the present study, the authors examined somatosensory processing in 30 biological relatives of persons with schizophrenia (hereafter called "schizophrenia relatives"), 30 biological relatives of persons with bipolar affective disorder (psychiatric family control subjects), and 30 healthy control subjects with no family history of psychopathology. All 3 groups completed a weight discrimination task, a 2-point discrimination task, and a complex cognitive somatosensory task (i.e., graphesthesia). The schizophrenia relatives performed significantly worse on all 3 somatosensory tasks compared with both the healthy control subjects and the bipolar relatives. The healthy control subjects and psychiatric family control subjects showed no significant differences on any of the somatosensory tasks. Within the weight discrimination and 2-point discrimination tasks, schizophrenia relatives showed group differences on the d' index, the measure of sensitivity, whereas all 3 groups did not differ on lnbeta, the measure of response bias, suggesting a genuine difference in weight and touch sensitivity. The d' value of the weight discrimination task was significantly associated with both the cognitive-perceptual factor and negative symptom factor of the clinical questionnaire (e.g., Schizotypal Personality Questionnaire; SPQ), whereas the 2-point discrimination d' value and graphesthesia scores were significantly associated only with the cognitive-perceptual factor of the SPQ. Implications for the possible relation between somatosensory task performance and schizophrenia liability are discussed.

  6. Detection of a weak somatosensory stimulus: role of the prestimulus mu rhythm and its top-down modulation.

    PubMed

    Zhang, Yan; Ding, Mingzhou

    2010-02-01

    The ongoing neural activity in human primary somatosensory cortex (SI) is characterized by field potential oscillations in the 7-13 Hz range known as the mu rhythm. Recent work has shown that the magnitude of the mu oscillation immediately preceding the onset of a weak stimulus has a significant impact on its detection. The neural mechanisms mediating this impact remain not well understood. In particular, whether and how somatosensory mu rhythm is modulated by executive areas prior to stimulus onset for improved behavioral performance has not been investigated. We addressed these issues by recording 128-channel scalp electroencephalogram from normal volunteers performing a somatosensory perception experiment in which they reported the detection of a near-threshold electrical stimulus ( approximately 50% detection rate) delivered to the right index finger. Three results were found. First, consistent with numerous previous reports, the N1 component ( approximately 140 msec) of the somatosensory-evoked potential was significantly enhanced for perceived stimulus compared to unperceived stimulus. Second, the prestimulus mu power and the evoked N1 amplitude exhibited an inverted-U relationship, suggesting that an intermediate level of prestimulus mu oscillatory activity is conducive to stimulus processing and perception. Third, a Granger causality analysis revealed that the prestimulus causal influence in the mu band from prefrontal cortex to SI was significantly higher for perceived stimulus than for unperceived stimulus, indicating that frontal executive structures, via ongoing mu oscillations, exert cognitive control over posterior sensory cortices to facilitate somatosensory processing.

  7. Allergic Contact Dermatitis

    MedlinePlus

    ... causes of allergic contact dermatitis include nickel, chromates, rubber chemicals, and topical antibiotic ointments and creams. Frequent ... construction workers who are in contact with cement. Rubber chemicals are found in gloves, balloons, elastic in ...

  8. Colored Contact Lens Dangers

    MedlinePlus

    ... Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Sep. 26, 2013 It ... the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In One Eye By ...

  9. Contact solution algorithms

    NASA Technical Reports Server (NTRS)

    Tielking, John T.

    1989-01-01

    Two algorithms for obtaining static contact solutions are described in this presentation. Although they were derived for contact problems involving specific structures (a tire and a solid rubber cylinder), they are sufficiently general to be applied to other shell-of-revolution and solid-body contact problems. The shell-of-revolution contact algorithm is a method of obtaining a point load influence coefficient matrix for the portion of shell surface that is expected to carry a contact load. If the shell is sufficiently linear with respect to contact loading, a single influence coefficient matrix can be used to obtain a good approximation of the contact pressure distribution. Otherwise, the matrix will be updated to reflect nonlinear load-deflection behavior. The solid-body contact algorithm utilizes a Lagrange multiplier to include the contact constraint in a potential energy functional. The solution is found by applying the principle of minimum potential energy. The Lagrange multiplier is identified as the contact load resultant for a specific deflection. At present, only frictionless contact solutions have been obtained with these algorithms. A sliding tread element has been developed to calculate friction shear force in the contact region of the rolling shell-of-revolution tire model.

  10. Glasses and Contact Lenses

    MedlinePlus

    ... Here's Help White House Lunch Recipes Glasses and Contact Lenses KidsHealth > For Kids > Glasses and Contact Lenses Print A A A Text Size What's ... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ...

  11. CONTACT URTICARIA: PRESENT SCENARIO

    PubMed Central

    Bhatia, Ruchi; Alikhan, Ali; Maibach, Howard I

    2009-01-01

    Immunological contact urticaria is a hypersensitivity reaction that appears on the skin following contact with an eliciting substance. Recent advances in our understanding of the molecular mechanism and pathogenesis of this reaction have altered its classification, diagnosis, and treatment. We discuss classification, epidemiology, diagnosis, testing, and treatment options that are available to patients with contact urticaria. PMID:20161861

  12. Optogenetic activation of zebrafish somatosensory neurons using ChEF-tdTomato.

    PubMed

    Palanca, Ana Marie S; Sagasti, Alvaro

    2013-01-01

    Larval zebrafish are emerging as a model for describing the development and function of simple neural circuits. Due to their external fertilization, rapid development, and translucency, zebrafish are particularly well suited for optogenetic approaches to investigate neural circuit function. In this approach, light-sensitive ion channels are expressed in specific neurons, enabling the experimenter to activate or inhibit them at will and thus assess their contribution to specific behaviors. Applying these methods in larval zebrafish is conceptually simple but requires the optimization of technical details. Here we demonstrate a procedure for expressing a channelrhodopsin variant in larval zebrafish somatosensory neurons, photo-activating single cells, and recording the resulting behaviors. By introducing a few modifications to previously established methods, this approach could be used to elicit behavioral responses from single neurons activated up to at least 4 days post-fertilization (dpf). Specifically, we created a transgene using a somatosensory neuron enhancer, CREST3, to drive the expression of the tagged channelrhodopsin variant, ChEF-tdTomato. Injecting this transgene into 1-cell stage embryos results in mosaic expression in somatosensory neurons, which can be imaged with confocal microscopy. Illuminating identified cells in these animals with light from a 473 nm DPSS laser, guided through a fiber optic cable, elicits behaviors that can be recorded with a high-speed video camera and analyzed quantitatively. This technique could be adapted to study behaviors elicited by activating any zebrafish neuron. Combining this approach with genetic or pharmacological perturbations will be a powerful way to investigate circuit formation and function. PMID:23407374

  13. The influence of visual perspective on the somatosensory steady-state response during pain observation

    PubMed Central

    Canizales, Dora L.; Voisin, Julien I. A.; Michon, Pierre-Emmanuel; Roy, Marc-André; Jackson, Philip L.

    2013-01-01

    The observation and evaluation of other’s pain activate part of the neuronal network involved in the actual experience of pain, including those regions subserving the sensori-discriminative dimension of pain. This was largely interpreted as evidence showing that part of the painful experience can be shared vicariously. Here, we investigated the effect of the visual perspective from which other people’s pain is seen on the cortical response to continuous 25 Hz non-painful somatosensory stimulation (somatosensory steady-state response: SSSR). Based on the shared representation framework, we expected first-person visual perspective (1PP) to yield more changes in cortical activity than third-person visual perspective (3PP) during pain observation. Twenty healthy adults were instructed to rate a series of pseudo-dynamic pictures depicting hands in either painful or non-painful scenarios, presented either in 1PP (0–45° angle) or 3PP (180° angle), while changes in brain activity was measured with a 128-electode EEG system. The ratings demonstrated that the same scenarios were rated on average as more painful when observed from the 1PP than from the 3PP. As expected from previous works, the SSSR response was decreased after stimulus onset over the left caudal part of the parieto-central cortex, contralateral to the stimulation side. Moreover, the difference between the SSSR was of greater amplitude when the painful situations were presented from the 1PP compared to the 3PP. Together, these results suggest that a visuospatial congruence between the viewer and the observed scenarios is associated with both a higher subjective evaluation of pain and an increased modulation in the somatosensory representation of observed pain. These findings are discussed with regards to the potential role of visual perspective in pain communication and empathy. PMID:24367323

  14. Ethnic differences in oro-facial somatosensory profiles-quantitative sensory testing in Chinese and Danes.

    PubMed

    Yang, G; Luo, Y; Baad-Hansen, L; Wang, K; Arendt-Nielsen, L; Xie, Q-F; Svensson, P

    2013-11-01

    Ethnic differences in pain experiences have been widely assessed in various pathological and experimental conditions. However, limited sensory modalities have been described in previous research, and the affective-motivational factors have so far been estimated to be the main mediator for the ethnic differences. This study aimed to detect the ethnic differences of oro-facial somatosensory profiles related to the sensory-discriminative dimension in healthy volunteers. The standardised quantitative sensory testing battery developed by the German Research Network on Neuropathic Pain was performed bilaterally in the infraorbital and mental regions on age- and gender-matched healthy Chinese and Danes, 29 participants each group. The influences of ethnicity, gender and test site on the somatosensory profile were evaluated by three-way anova. The ethnic disparities were also presented by Z-scores. Compared to Danes, Chinese were more sensitive to thermal detection, thermal pain, mechanical deep pain and mechanical pain rating parameters (P < 0·002) related to small fibre functions. However, the inverse results were observed for mechanical tactile modality related to large fibre function (P < 0·001) and wind-up ratio (P = 0·006). Women presented higher sensitivity compared to men. The mean Z-scores of all the parameters from Chinese group were in the normal zone created by Danish Caucasians' means and SDs. The ethnic disparities in somatosensory profile illustrated the necessity of establishing the reference data for different ethnic groups and possibly individual pain management strategies for the different ethnic groups.

  15. The functional and anatomical dissection of somatosensory subpopulations using mouse genetics

    PubMed Central

    Le Pichon, Claire E.; Chesler, Alexander T.

    2014-01-01

    The word somatosensation comes from joining the Greek word for body (soma) with a word for perception (sensation). Somatosensory neurons comprise the largest sensory system in mammals and have nerve endings coursing throughout the skin, viscera, muscle, and bone. Their cell bodies reside in a chain of ganglia adjacent to the dorsal spinal cord (the dorsal root ganglia) and at the base of the skull (the trigeminal ganglia). While the neuronal cell bodies are intermingled within the ganglia, the somatosensory system is in reality composed of numerous sub-systems, each specialized to detect distinct stimuli, such as temperature and touch. Historically, somatosensory neurons have been classified using a diverse host of anatomical and physiological parameters, such as the size of the cell body, degree of myelination, histological labeling with markers, specialization of the nerve endings, projection patterns in the spinal cord and brainstem, receptive tuning, and conduction velocity of their action potentials. While useful, the picture that emerged was one of heterogeneity, with many markers at least partially overlapping. More recently, by capitalizing on advances in molecular techniques, researchers have identified specific ion channels and sensory receptors expressed in subsets of sensory neurons. These studies have proved invaluable as they allow genetic access to small subsets of neurons for further molecular dissection. Data being generated from transgenic mice favor a model whereby an array of dedicated neurons is responsible for selectively encoding different modalities. Here we review the current knowledge of the different sensory neuron subtypes in the mouse, the markers used to study them, and the neurogenetic strategies used to define their anatomical projections and functional roles. PMID:24795573

  16. Somatosensory phenotype is associated with thalamic metabolites and pain intensity after spinal cord injury

    PubMed Central

    Widerström-Noga, Eva; Cruz-Almeida, Yenisel; Felix, Elizabeth R.; Pattany, Pradip M.

    2015-01-01

    Neuropathic pain is one of the most difficult consequences of spinal cord injury (SCI). The clinical correlates of the underlying mechanisms responsible for neuropathic pain are not well understood, although methods such as quantitative somatosensory testing (QST) or brain imaging have been used to further a mechanism-based understanding of pain. Our previous SCI study demonstrated a significantly lower glutamate-glutamine/myo-inositol ratio (Glx/Ins) in the anterior cingulate cortex in persons with severe neuropathic pain compared with those with less severe neuropathic pain or pain-free, able-bodied controls, suggesting that a combination of decreased glutamatergic metabolism and glial activation may contribute to the development of severe neuropathic pain after SCI. The present study aimed to determine the relationships between somatosensory function below the level of injury and low thalamic Glx/Ins in persons with intense neuropathic pain after SCI. Participants underwent QST and a 3 Tesla proton magnetic resonance spectroscopy. A cluster analysis including SCI participants resulted in 1 group (n = 19) with significantly (P < 0.001) greater pain intensity (6.43 ± 1.63; high neuropathic pain [HNP], and lower Glx/Ins [1.22 ± 0.16]) and another group (n = 35) with lower pain intensity ratings (1.59 ± 1.52, low neuropathic pain [LNP], and higher Glx/Ins [1.47 ± 0.26]). After correcting for age, QST indicated significantly greater somatosensory function in the HNP group compared with the LNP group. Our results are consistent with research suggesting that damage to, but not abolition of, the spinothalamic tract contributes to development of neuropathic pain after SCI and that secondary inflammatory processes may amplify residual spinothalamic tract signals by facilitation, disinhibition, or sensitization. PMID:25599312

  17. Somatosensory phenotype is associated with thalamic metabolites and pain intensity after spinal cord injury.

    PubMed

    Widerström-Noga, Eva; Cruz-Almeida, Yenisel; Felix, Elizabeth R; Pattany, Pradip M

    2015-01-01

    Neuropathic pain is one of the most difficult consequences of spinal cord injury (SCI). The clinical correlates of the underlying mechanisms responsible for neuropathic pain are not well understood, although methods such as quantitative somatosensory testing (QST) or brain imaging have been used to further a mechanism-based understanding of pain. Our previous SCI study demonstrated a significantly lower glutamate-glutamine/myo-inositol ratio (Glx/Ins) in the anterior cingulate cortex in persons with severe neuropathic pain compared with those with less severe neuropathic pain or pain-free, able-bodied controls, suggesting that a combination of decreased glutamatergic metabolism and glial activation may contribute to the development of severe neuropathic pain after SCI. The present study aimed to determine the relationships between somatosensory function below the level of injury and low thalamic Glx/Ins in persons with intense neuropathic pain after SCI. Participants underwent QST and a 3 Tesla proton magnetic resonance spectroscopy. A cluster analysis including SCI participants resulted in 1 group (n = 19) with significantly (P < 0.001) greater pain intensity (6.43 ± 1.63; high neuropathic pain [HNP], and lower Glx/Ins [1.22 ± 0.16]) and another group (n = 35) with lower pain intensity ratings (1.59 ± 1.52, low neuropathic pain [LNP], and higher Glx/Ins [1.47 ± 0.26]). After correcting for age, QST indicated significantly greater somatosensory function in the HNP group compared with the LNP group. Our results are consistent with research suggesting that damage to, but not abolition of, the spinothalamic tract contributes to development of neuropathic pain after SCI and that secondary inflammatory processes may amplify residual spinothalamic tract signals by facilitation, disinhibition, or sensitization.

  18. Altered somatosensory barrel cortex refinement in the developing brain of Mecp2-null mice.

    PubMed

    Moroto, M; Nishimura, A; Morimoto, M; Isoda, K; Morita, T; Yoshida, M; Morioka, S; Tozawa, T; Hasegawa, T; Chiyonobu, T; Yoshimoto, K; Hosoi, H

    2013-11-01

    Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl-CpG binding protein 2 (MeCP2) gene. In previous studies, monoaminergic dysfunctions have been detected in patients with RTT and in a murine model of RTT, the Mecp2-null mouse. Therefore, the pathogenesis of RTT is thought to involve impairments in the monoaminergic systems. However, there have been limited data showing that the impairment of monoamines leads to early symptoms during development. We used histochemistry to study the somatosensory barrel cortex in the B6.129P2(C)-Mecp2(tm1.1Bird) mouse model of RTT. The barrel cortex is widely used to investigate neuronal development and its regulation by various neurotransmitters including 5-HT. 5-HT levels were measured by high performance liquid chromatography with electrochemical detection (HPLC/EC), and serotonin transporter (SERT) and 5-HT1B receptor mRNAs were measured in the somatosensory cortex, thalamus and striatum on postnatal days (P) 10, P20 and P40. Mecp2-null mice (Mecp2-/y) had significantly smaller barrel fields than age-matched wild-type controls (Mecp2+/y) on P10 and P40, but the topographic map was accurately formed. Levels of 5-HT, and SERT and 5-HT1B receptor mRNA expression in the somatosensory cortex did not differ significantly between the Mecp2-null and wild-type mice on P10. However, thalamic 5-HT was reduced in Mecp2-null mice. Our data indicate that a lack of MeCP2 may disturb the refinement of the barrel cortex in the early postnatal period. Our findings suggest that a decrease in thalamic 5-HT might be involved in this phenomenon.

  19. Nociceptive stimuli induce changes in somatosensory responses of rat dorsal column nuclei neurons.

    PubMed

    Costa-García, Miguel; Nuñez, Angel

    2004-10-29

    Accumulating evidence suggest that the dorsal column nuclei (DCN) neurons play a role in nociception. To evaluate DCN neuronal responses to nociceptive stimuli, unit recordings were performed in urethane-anesthesized rats. Neurons selected for this analysis displayed a low spontaneous firing rate and some of them were antidromically activated by electrical stimulation of the ventral posterolateral thalamic nucleus. Formalin injections into receptive fields (RFs) of DCN cells, or applications of short-lasting and long-lasting thermal nociceptive stimuli were used. DCN neurons displayed smaller responses when long-lasting nociceptive thermal stimuli were applied to their RFs in comparison with values obtained from the innocuous cutaneous stimulation (5.2+/-1.0 and 4.0+/-0.6 spikes/stimuli, respectively; p=0.02). Formalin also decreased the responses to innocuous cutaneous stimuli when these stimuli were applied to the formalin injection site (2.6+/-0.3 spikes/stimuli in control conditions and 1.8+/-0.3 spikes/stimuli 20 min after formalin; p=0.002). In contrast, responses to sensory stimuli applied at the periphery of the RF after formalin injection increased (2.2+/-0.2 to 2.8+/-0.3 spikes/stimuli; p=0.005). In some cases, DCN neurons expanded their RF. Fiber input to the DCN did not modify their somatosensory responses when nociceptive stimuli were applied. Results demonstrate that thermal and formalin nociceptive stimuli modify the somatosensory responses of DCN neurons. Thus, decreasing somatosensory responses at the pain induction site or the generation of allodynia may be due to the activity of DCN neurons.

  20. The functional and anatomical dissection of somatosensory subpopulations using mouse genetics.

    PubMed

    Le Pichon, Claire E; Chesler, Alexander T

    2014-01-01

    The word somatosensation comes from joining the Greek word for body (soma) with a word for perception (sensation). Somatosensory neurons comprise the largest sensory system in mammals and have nerve endings coursing throughout the skin, viscera, muscle, and bone. Their cell bodies reside in a chain of ganglia adjacent to the dorsal spinal cord (the dorsal root ganglia) and at the base of the skull (the trigeminal ganglia). While the neuronal cell bodies are intermingled within the ganglia, the somatosensory system is in reality composed of numerous sub-systems, each specialized to detect distinct stimuli, such as temperature and touch. Historically, somatosensory neurons have been classified using a diverse host of anatomical and physiological parameters, such as the size of the cell body, degree of myelination, histological labeling with markers, specialization of the nerve endings, projection patterns in the spinal cord and brainstem, receptive tuning, and conduction velocity of their action potentials. While useful, the picture that emerged was one of heterogeneity, with many markers at least partially overlapping. More recently, by capitalizing on advances in molecular techniques, researchers have identified specific ion channels and sensory receptors expressed in subsets of sensory neurons. These studies have proved invaluable as they allow genetic access to small subsets of neurons for further molecular dissection. Data being generated from transgenic mice favor a model whereby an array of dedicated neurons is responsible for selectively encoding different modalities. Here we review the current knowledge of the different sensory neuron subtypes in the mouse, the markers used to study them, and the neurogenetic strategies used to define their anatomical projections and functional roles. PMID:24795573

  1. Differential changes in gingival somatosensory sensitivity after painful electrical tooth stimulation.

    PubMed

    Baad-Hansen, Lene; Lu, Shengyi; Kemppainen, Pentti; List, Thomas; Zhang, Zhenting; Svensson, Peter

    2015-04-01

    We aimed to evaluate the effect of painful tooth stimulation on gingival somatosensory sensitivity of healthy volunteers in a randomized, controlled design. Thirteen healthy volunteers (six women, seven men; 28.4 ± 5.0 years) were included for two experimental sessions of electrical tooth stimulation: painful tooth stimulation and tooth stimulation below the sensory threshold (control). Eight of the human subjects participated in a third session without tooth stimulation. In all sessions, the somatosensory sensitivity of the gingiva adjacent to the stimulated tooth was evaluated with a standardized battery of quantitative sensory tests (QST) before, immediately after and 30 min after tooth stimulation. Painful tooth stimulation evoked significant decreases in warmth and heat pain thresholds (P < 0.001) as well as pressure pain thresholds (increased sensitivity) (P = 0.024) and increases in mechanical detection thresholds (decreased sensitivity) (P < 0.050). Similar thermal threshold changes (P < 0.019) but no mechanical changes were found after tooth stimulation below the sensory threshold (P > 0.086). No QST changes were detected in the session without tooth stimulation (P > 0.060). In conclusion, modest increased gingival sensitivity to warmth, painful heat and pressure stimuli as well as desensitization to non-painful mechanical stimulation were demonstrated after tooth stimulation. This suggests involvement of competing heterotopic facilitatory and inhibitory mechanisms. Furthermore, stimulation below the sensory threshold induced similar thermal sensitization suggesting the possibility of activation of axon-reflex-like mechanisms even at intensities below the perception threshold. These findings may have implications for interpretation of somatosensory results in patients with chronic intraoral pain. PMID:25567087

  2. Differential changes in gingival somatosensory sensitivity after painful electrical tooth stimulation.

    PubMed

    Baad-Hansen, Lene; Lu, Shengyi; Kemppainen, Pentti; List, Thomas; Zhang, Zhenting; Svensson, Peter

    2015-04-01

    We aimed to evaluate the effect of painful tooth stimulation on gingival somatosensory sensitivity of healthy volunteers in a randomized, controlled design. Thirteen healthy volunteers (six women, seven men; 28.4 ± 5.0 years) were included for two experimental sessions of electrical tooth stimulation: painful tooth stimulation and tooth stimulation below the sensory threshold (control). Eight of the human subjects participated in a third session without tooth stimulation. In all sessions, the somatosensory sensitivity of the gingiva adjacent to the stimulated tooth was evaluated with a standardized battery of quantitative sensory tests (QST) before, immediately after and 30 min after tooth stimulation. Painful tooth stimulation evoked significant decreases in warmth and heat pain thresholds (P < 0.001) as well as pressure pain thresholds (increased sensitivity) (P = 0.024) and increases in mechanical detection thresholds (decreased sensitivity) (P < 0.050). Similar thermal threshold changes (P < 0.019) but no mechanical changes were found after tooth stimulation below the sensory threshold (P > 0.086). No QST changes were detected in the session without tooth stimulation (P > 0.060). In conclusion, modest increased gingival sensitivity to warmth, painful heat and pressure stimuli as well as desensitization to non-painful mechanical stimulation were demonstrated after tooth stimulation. This suggests involvement of competing heterotopic facilitatory and inhibitory mechanisms. Furthermore, stimulation below the sensory threshold induced similar thermal sensitization suggesting the possibility of activation of axon-reflex-like mechanisms even at intensities below the perception threshold. These findings may have implications for interpretation of somatosensory results in patients with chronic intraoral pain.

  3. Increased excitability of somatosensory cortex in aged humans is associated with impaired tactile acuity.

    PubMed

    Lenz, Melanie; Tegenthoff, Martin; Kohlhaas, Karsten; Stude, Philipp; Höffken, Oliver; Gatica Tossi, Mario A; Kalisch, Tobias; Kowalewski, Rebecca; Dinse, Hubert R

    2012-02-01

    Aging affects all levels of neural processing, including changes of intracortical inhibition and cortical excitability. Paired-pulse stimulation, the application of two stimuli in close succession, is a useful tool to investigate cortical excitability in humans. The paired-pulse behavior is characterized by the second response being significantly suppressed at short stimulus onset asynchronies. While in rat somatosensory cortex, intracortical inhibition has been demonstrated to decline with increasing age, data from human motor cortex of elderly subjects are controversial and there are no data for the human somatosensory cortex (SI). Moreover, behavioral implications of age-related changes of cortical excitability remain elusive. We therefore assessed SI excitability by combining paired-pulse median nerve stimulation with recording somatosensory evoked potentials in 138 healthy subjects aged 17-86 years. We found that paired-pulse suppression was characterized by substantial interindividual variability, but declined significantly with age, confirming reduced intracortical inhibition in elderly subjects. To link the age-related increase of cortical excitability to perceptual changes, we measured tactile two-point discrimination in a subsample of 26 aged participants who showed either low or high paired-pulse suppression. We found that tactile performance was particularly impaired in subjects showing markedly enhanced cortical excitability. Our data demonstrate that paired-pulse suppression of human SI is significantly reduced in older adults, and that age-related enhancement of cortical excitability correlates with degradation of tactile perception. These findings indicate that cortical excitability constitutes an important mechanism that links age-related neurophysiological changes to behavioral alterations in humans.

  4. Ferromagnetic tunnel contacts to graphene: Contact resistance and spin signal

    SciTech Connect

    Cubukcu, M.; Laczkowski, P.; Vergnaud, C.; Marty, A.; Attané, J.-P.; Notin, L.; Vila, L. Jamet, M.; Martin, M.-B.; Seneor, P.; Anane, A.; Deranlot, C.; Fert, A.; Auffret, S.; Ducruet, C.

    2015-02-28

    We report spin transport in CVD graphene-based lateral spin valves using different magnetic contacts. We compared the spin signal amplitude measured on devices where the cobalt layer is directly in contact with the graphene to the one obtained using tunnel contacts. Although a sizeable spin signal (up to ∼2 Ω) is obtained with direct contacts, the signal is strongly enhanced (∼400 Ω) by inserting a tunnel barrier. In addition, we studied the resistance-area product (R.A) of a variety of contacts on CVD graphene. In particular, we compared the R.A products of alumina and magnesium oxide tunnel barriers grown by sputtering deposition of aluminum or magnesium and subsequent natural oxidation under pure oxygen atmosphere or by plasma. When using an alumina tunnel barrier on CVD graphene, the R.A product is high and exhibits a large dispersion. This dispersion can be highly reduced by using a magnesium oxide tunnel barrier, as for the R.A value. This study gives insight in the material quest for reproducible and efficient spin injection in CVD graphene.

  5. Cortical astrocytes rewire somatosensory cortical circuits for peripheral neuropathic pain.

    PubMed

    Kim, Sun Kwang; Hayashi, Hideaki; Ishikawa, Tatsuya; Shibata, Keisuke; Shigetomi, Eiji; Shinozaki, Youichi; Inada, Hiroyuki; Roh, Seung Eon; Kim, Sang Jeong; Lee, Gihyun; Bae, Hyunsu; Moorhouse, Andrew J; Mikoshiba, Katsuhiko; Fukazawa, Yugo; Koizumi, Schuichi; Nabekura, Junichi

    2016-05-01

    Long-term treatments to ameliorate peripheral neuropathic pain that includes mechanical allodynia are limited. While glial activation and altered nociceptive transmission within the spinal cord are associated with the pathogenesis of mechanical allodynia, changes in cortical circuits also accompany peripheral nerve injury and may represent additional therapeutic targets. Dendritic spine plasticity in the S1 cortex appears within days following nerve injury; however, the underlying cellular mechanisms of this plasticity and whether it has a causal relationship to allodynia remain unsolved. Furthermore, it is not known whether glial activation occurs within the S1 cortex following injury or whether it contributes to this S1 synaptic plasticity. Using in vivo 2-photon imaging with genetic and pharmacological manipulations of murine models, we have shown that sciatic nerve ligation induces a re-emergence of immature metabotropic glutamate receptor 5 (mGluR5) signaling in S1 astroglia, which elicits spontaneous somatic Ca2+ transients, synaptogenic thrombospondin 1 (TSP-1) release, and synapse formation. This S1 astrocyte reactivation was evident only during the first week after injury and correlated with the temporal changes in S1 extracellular glutamate levels and dendritic spine turnover. Blocking the astrocytic mGluR5-signaling pathway suppressed mechanical allodynia, while activating this pathway in the absence of any peripheral injury induced long-lasting (>1 month) allodynia. We conclude that reawakened astrocytes are a key trigger for S1 circuit rewiring and that this contributes to neuropathic mechanical allodynia. PMID:27064281

  6. Cortical astrocytes rewire somatosensory cortical circuits for peripheral neuropathic pain

    PubMed Central

    Hayashi, Hideaki; Ishikawa, Tatsuya; Shibata, Keisuke; Inada, Hiroyuki; Roh, Seung Eon; Kim, Sang Jeong; Moorhouse, Andrew J.

    2016-01-01

    Long-term treatments to ameliorate peripheral neuropathic pain that includes mechanical allodynia are limited. While glial activation and altered nociceptive transmission within the spinal cord are associated with the pathogenesis of mechanical allodynia, changes in cortical circuits also accompany peripheral nerve injury and may represent additional therapeutic targets. Dendritic spine plasticity in the S1 cortex appears within days following nerve injury; however, the underlying cellular mechanisms of this plasticity and whether it has a causal relationship to allodynia remain unsolved. Furthermore, it is not known whether glial activation occurs within the S1 cortex following injury or whether it contributes to this S1 synaptic plasticity. Using in vivo 2-photon imaging with genetic and pharmacological manipulations of murine models, we have shown that sciatic nerve ligation induces a re-emergence of immature metabotropic glutamate receptor 5 (mGluR5) signaling in S1 astroglia, which elicits spontaneous somatic Ca2+ transients, synaptogenic thrombospondin 1 (TSP-1) release, and synapse formation. This S1 astrocyte reactivation was evident only during the first week after injury and correlated with the temporal changes in S1 extracellular glutamate levels and dendritic spine turnover. Blocking the astrocytic mGluR5-signaling pathway suppressed mechanical allodynia, while activating this pathway in the absence of any peripheral injury induced long-lasting (>1 month) allodynia. We conclude that reawakened astrocytes are a key trigger for S1 circuit rewiring and that this contributes to neuropathic mechanical allodynia. PMID:27064281

  7. Somatosensory evoked potentials aid prediction after hypoxic-ischaemic brain injury.

    PubMed

    Kane, Nick; Oware, Agyepong

    2015-10-01

    Cardiopulmonary resuscitation, basic life support and early defibrillation are leading to more survivors of out-of-hospital cardiac arrest reaching hospital. Once stabilised on an intensive care unit, it can be difficult to predict the neurological outcome using clinical criteria alone, particularly with modern management using sedation, neuromuscular blockade and hypothermia. If we are to prevent ongoing futile life support, it is important to try to identify the majority of patients who, despite best efforts, will not make a meaningful recovery. Somatosensory evoked potentials are widely available electrophysiological tests that can provide an objective biomarker of a poor neurological outcome and assist in predicting the prognosis.

  8. Alteration of digital representations in somatosensory cortex in focal hand dystonia.

    PubMed

    Elbert, T; Candia, V; Altenmüller, E; Rau, H; Sterr, A; Rockstroh, B; Pantev, C; Taub, E

    1998-11-16

    Focal hand dystonia involves a loss of motor control of one or more digits; it is associated with the repetitive, synchronous movements of the digits made by musicians over periods of many years. Magnetic source imaging revealed that there is a smaller distance (fusion) between the representations of the digits in somatosensory cortex for the affected hand of dystonic musicians than for the hands of non-musician control subjects. The data suggest that use-dependent susceptibility to digital representation fusion in cortex may be involved in the etiology of focal dystonia. A successful therapy for the condition has been developed based on this consideration.

  9. Early development of a somatosensory fovea: a head start in the cortical space race?

    PubMed

    Catania, K C

    2001-04-01

    Star-nosed moles have 11 mechanosensory appendages surrounding each nostril, and primary afferents from a single appendage-the tactile fovea-are greatly over-represented in somatosensory cortex. It was found that the foveal appendage led development in the periphery, had the greatest innervated surface area in embryos, and developed mature nerve terminals and epidermal sensory organs first; also, in developing cortex, markers for metabolic activity (cytochrome oxidase) appeared first in the fovea representation. This developmental sequence may provide the fovea with an advantage in a competition for cortical space, and account for the much larger areas of cortex devoted to foveal afferents. PMID:11276222

  10. Functional response of cerebral blood flow induced by somatosensory stimulation in rats with subarachnoid hemorrhage

    NASA Astrophysics Data System (ADS)

    Li, Zhiguo; Huang, Qin; Liu, Peng; Li, Pengcheng; Ma, Lianting; Lu, Jinling

    2015-09-01

    Subarachnoid hemorrhage (SAH) is often accompanied by cerebral vasospasm (CVS), which is the phenomenon of narrowing of large cerebral arteries, and then can produce delayed ischemic neurological deficit (DIND) such as lateralized sensory dysfunction. CVS was regarded as a major contributor to DIND in patients with SAH. However, therapy for preventing vasospasm after SAH to improve the outcomes may not work all the time. It is important to find answers to the relationship between CVS and DIND after SAH. How local cerebral blood flow (CBF) is regulated during functional activation after SAH still remains poorly understood, whereas, the regulation of CBF may play an important role in weakening the impact of CVS on cortex function. Therefore, it is worthwhile to evaluate the functional response of CBF in the activated cortex in an SAH animal model. Most evaluation of the effect of SAH is presently carried out by neurological behavioral scales. The functional imaging of cortical activation during sensory stimulation may help to reflect the function of the somatosensory cortex more locally than the behavioral scales do. We investigated the functional response of CBF in the somatosensory cortex induced by an electrical stimulation to contralateral forepaw via laser speckle imaging in a rat SAH model. Nineteen Sprague-Dawley rats from two groups (control group, n=10 and SAH group, n=9) were studied. SAH was induced in rats by double injection of autologous blood into the cisterna magna after CSF aspiration. The same surgical procedure was applied in the control group without CSF aspiration or blood injection. Significant CVS was found in the SAH group. Meanwhile, we observed a delayed peak of CBF response in rats with SAH compared with those in the control group, whereas no significant difference was found in magnitude, duration, and areas under curve of relative CBF changes between the two groups. The results suggest that the regulation function of local CBF during

  11. Early development of a somatosensory fovea: a head start in the cortical space race?

    PubMed

    Catania, K C

    2001-04-01

    Star-nosed moles have 11 mechanosensory appendages surrounding each nostril, and primary afferents from a single appendage-the tactile fovea-are greatly over-represented in somatosensory cortex. It was found that the foveal appendage led development in the periphery, had the greatest innervated surface area in embryos, and developed mature nerve terminals and epidermal sensory organs first; also, in developing cortex, markers for metabolic activity (cytochrome oxidase) appeared first in the fovea representation. This developmental sequence may provide the fovea with an advantage in a competition for cortical space, and account for the much larger areas of cortex devoted to foveal afferents.

  12. Analysis of pain-related somatosensory evoked magnetic fields using the MUSIC (multiple signal classification) algorithm for magnetoencephalography.

    PubMed

    Ninomiya, Y; Kitamura, Y; Yamamoto, S; Okamoto, M; Oka, H; Yamada, N; Kuroda, S

    2001-06-13

    We evaluated the effectiveness of the Multiple Signal Classification (MUSIC) algorithm by analysing pain-related somatosensory-evoked magnetic fields (SEFs) by 148-channel whole-head-type magnetoencephalography. MUSIC peaks of middle latency components were located around the primary somatosensory cortex (SI), contralateral to the stimulated finger. Long latency components were located around the bilateral secondary somatosensory cortices (SII) and cingulate gyri. Peaks at the SII and cingulate gyri were more prominent on very painful and moderately painful stimulation than on weak stimulation. The results were in very good agreement with results from single dipole estimation. These findings suggest that the MUSIC algorithm could be a useful tool for analysis of pain-related SEFs.

  13. [The dynamics of somatosensory and visual evoked potentials as a correlate of reversible states of altered consciousness].

    PubMed

    Gordeev, S A; Baziian, B Kh; Liubimov, N N

    1992-11-01

    Somatosensory and visual evoked potentials (EPs) of the brain of 17 sensitive subjects (extrasenses) and 12 ordinary healthy subjects were studied. It was found that during extrasensory activity (direct impact, meditation) in comparison to rest values, the amplitude of intermediate and late components of visual and somatosensory EPs of both hemispheres and early components of somatosensory EPs of ipsilateral in relation to stimulation hemisphere diminished 2-4--fold. There was a recovery of these components after discontinuation of extrasensory activity. It is shown that ordinary subjects could not change their EPs when they tried their best to decrease EPs. It is shown that ordinary subjects could not change their EPs when they tried their best to decrease EPs. It is suggested that the ability of extrasenses for reversible changes of their mind by direct adjustment of the activity of the ascending nonspecific systems of the brain and by alterations of interhemispheric relations forms the basis of extrasensory activity.

  14. Contact lens in keratoconus

    PubMed Central

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  15. Complementary Barrier Infrared Detector (CBIRD) Contact Methods

    NASA Technical Reports Server (NTRS)

    Ting, David Z.; Hill, Cory J.; Gunapala, Sarath D.

    2013-01-01

    The performance of the CBIRD detector is enhanced by using new device contacting methods that have been developed. The detector structure features a narrow gap adsorber sandwiched between a pair of complementary, unipolar barriers that are, in turn, surrounded by contact layers. In this innovation, the contact adjacent to the hole barrier is doped n-type, while the contact adjacent to the electron barrier is doped p-type. The contact layers can have wider bandgaps than the adsorber layer, so long as good electrical contacts are made to them. If good electrical contacts are made to either (or both) of the barriers, then one could contact the barrier(s) directly, obviating the need for additional contact layers. Both the left and right contacts can be doped either n-type or ptype. Having an n-type contact layer next to the electron barrier creates a second p-n junction (the first being the one between the hole barrier and the adsorber) over which applied bias could drop. This reduces the voltage drop over the adsorber, thereby reducing dark current generation in the adsorber region.

  16. Chronic stress and peripheral pain: Evidence for distinct, region-specific changes in visceral and somatosensory pain regulatory pathways.

    PubMed

    Zheng, Gen; Hong, Shuangsong; Hayes, John M; Wiley, John W

    2015-11-01

    Chronic stress alters the hypothalamic-pituitary-adrenal (HPA) axis and enhances visceral and somatosensory pain perception. It is unresolved whether chronic stress has distinct effects on visceral and somatosensory pain regulatory pathways. Previous studies reported that stress-induced visceral hyperalgesia is associated with reciprocal alterations of endovanilloid and endocannabinoid pain pathways in DRG neurons innervating the pelvic viscera. In this study, we compared somatosensory and visceral hyperalgesia with respect to differential responses of peripheral pain regulatory pathways in a rat model of chronic, intermittent stress. We found that chronic stress induced reciprocal changes in the endocannabinoid 2-AG (increased) and endocannabinoid degradation enzymes COX-2 and FAAH (decreased), associated with down-regulation of CB1 and up-regulation of TRPV1 receptors in L6-S2 DRG but not L4-L5 DRG neurons. In contrast, sodium channels Nav1.7 and Nav1.8 were up-regulated in L4-L5 but not L6-S2 DRGs in stressed rats, which was reproduced in control DRGs treated with corticosterone in vitro. The reciprocal changes of CB1, TRPV1 and sodium channels were cell-specific and observed in the sub-population of nociceptive neurons. Behavioral assessment showed that visceral hyperalgesia persisted, whereas somatosensory hyperalgesia and enhanced expression of Nav1.7 and Nav1.8 sodium channels in L4-L5 DRGs normalized 3 days after completion of the stress phase. These data indicate that chronic stress induces visceral and somatosensory hyperalgesia that involves differential changes in endovanilloid and endocannabinoid pathways, and sodium channels in DRGs innervating the pelvic viscera and lower extremities. These results suggest that chronic stress-induced visceral and lower extremity somatosensory hyperalgesia can be treated selectively at different levels of the spinal cord. PMID:26408049

  17. Chronic Stress and Peripheral Pain: Evidence for Distinct, Region-specific Changes in Visceral and Somatosensory Pain Regulatory Pathways

    PubMed Central

    Zheng, Gen; Hong, Shuangsong; Hayes, John M; Wiley, John W

    2015-01-01

    Chronic stress alters the hypothalamic-pituitary-adrenal (HPA) axis and enhances visceral and somatosensory pain perception. It is unresolved whether chronic stress has distinct effects on visceral and somatosensory pain regulatory pathways. Previous studies reported that stress-induced visceral hyperalgesia is associated with reciprocal alterations of endovanilloid and endocannabinoid pain pathways in DRG neurons innervating the pelvic viscera. In this study, we compared somatosensory and visceral hyperalgesia with respect to differential responses of peripheral pain regulatory pathways in a rat model of chronic, intermittent stress. We found that chronic stress induced reciprocal changes in the endocannabinoid 2-AG (increased) and endocannabinoid degradation enzymes COX-2 and FAAH (decreased), associated with down-regulation of CB1 and up-regulation of TRPV1 receptors in L6-S2 DRG but not L4-L5 DRG neurons. In contrast, sodium channels Nav1.7 and Nav1.8 were up-regulated in L4-L5 but not L6-S2 DRGs in stressed rats, which was reproduced in control L4-L5 DRGs treated with corticosterone in vitro. The reciprocal changes of CB1, TRPV1 and sodium channels were cell-specific and observed in the sub-population of nociceptive neurons. Behavioral assessment showed that visceral hyperalgesia persisted, whereas somatosensory hyperalgesia and enhanced expression of Nav1.7 and Nav1.8 sodium channels in L4-L5 DRGs normalized 3 days after completion of the stress phase. These data indicate that chronic stress induces visceral and somatosensory hyperalgesia that involves differential changes in endovanilloid and endocannabinoid pathways, and sodium channels in DRGs innervating the pelvic viscera and lower extremities. These results suggest that chronic stress-induced visceral and lower extremity somatosensory hyperalgesia can be treated selectively at different levels of the spinal cord. PMID:26408049

  18. Elastohydrodynamic lubrication of elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1982-01-01

    Fully flooded, elastohydrodynamically lubricated, elliptical contacts are discussed. The relevant equations used in the elastohydrodynamic lubrication (EHL) of elliptical contacts are briefly described. Film thickness equations are developed for materials of high elastic modulus, such as metal, and for materials of low elastic modulus, such as rubber. In addition to the film thickness equations that are developed, plots of pressure and film thickness are presented. A theoretical study of the influence of lubricant starvation on film thickness and pressure in hard and soft elliptical elastohydrodynamic contacts is presented. From the results for both hard and soft EHL contacts a simple and important dimensionless inlet boundary distance is specified. It is also found that the film thickness for a starved condition can be written in dimensionless terms as a function of the inlet distance parameter and the film thickness for a fully flooded condition. contour plots of pressure and film thickness in and around the contact are shown for fully flooded and starved conditions. The theoretical findings are compared directly with results obtained experimentally.

  19. The relationship of a monoamine fiber system to a somatosensory tectal projection in the salamander Ambystoma tigrinum.

    PubMed

    Gruberg, E R; Solish, S P

    1978-08-01

    After hemisection of the spinal cord and medulla oblongata, a projection has been traced to the inner half of the tectal white of the tiger salamander, using Fink-Heimer degeneration staining. By microelectrode recording it was found that the tectal projection forms a topographic somatosensory map of the contralateral half of the body. This map is in register with the overlying retino-tectal visual projection. Using the Falck-Hillarp technique, it was found that the somatosensory tectal input is associated with yellow-fluorescing 5-hydroxytryptamine fibers.

  20. Inherited erythromelalgia due to mutations in SCN9A: natural history, clinical phenotype and somatosensory profile.

    PubMed

    McDonnell, Aoibhinn; Schulman, Betsy; Ali, Zahid; Dib-Hajj, Sulayman D; Brock, Fiona; Cobain, Sonia; Mainka, Tina; Vollert, Jan; Tarabar, Sanela; Waxman, Stephen G

    2016-04-01

    Inherited erythromelalgia, the first human pain syndrome linked to voltage-gated sodium channels, is widely regarded as a genetic model of human pain. Because inherited erythromelalgia was linked to gain-of-function changes of sodium channel Na(v)1.7 only a decade ago, the literature has mainly consisted of reports of genetic and/or clinical characterization of individual patients. This paper describes the pattern of pain, natural history, somatosensory profile, psychosocial status and olfactory testing of 13 subjects with primary inherited erythromelalgia with mutations of SCN9A, the gene encoding Na(v)1.7. Subjects were clinically profiled using questionnaires, quantitative sensory testing and olfaction testing during the in-clinic phase of the study. In addition, a detailed pain phenotype for each subject was obtained over a 3-month period at home using diaries, enabling subjects to self-report pain attacks, potential triggers, duration and severity of pain. All subjects reported pain and heat in the extremities (usually feet and/or hands), with pain attacks triggered by heat or exercise and relieved mainly by non-pharmacological manoeuvres such as cooling. A large proportion of pain attacks (355/1099; 32%) did not involve a specific trigger. There was considerable variability in the number, duration and severity of pain attacks between subjects, even those carrying the same mutation within a family, and within individuals over the 12-13 week observation period. Most subjects (11/13) had pain between attacks. For these subjects, mean pain severity between pain attacks was usually lower than that during an attack. Olfaction testing using the Sniffin'T test did not demonstrate hyperosmia. One subject had evidence of orthostatic hypotension. Overall, there was a statistically significant correlation between total Hospital Anxiety and Depression Scale scores (P= 0.005) and pain between attacks and for Hospital Anxiety and Depression Scale Depression scores and pain

  1. Non-contact measurement of contact wire

    NASA Astrophysics Data System (ADS)

    Yi, Yaxing; Ye, Xuemei; Li, Zhongke; Yue, Kaiduan

    2008-12-01

    The overhead contact system is the power supply unit of the electric locomotive. This article is to introduce our newly developed method to measure the height and pull out value of the contact wire. A carema dolly which can move on railway is applied to bear the weight of the measure equipment; two linear CCD cameras are installed on the dolly symmetrically about the midline of two rails. While the dolly move along the railway, two CCD cameras grasp the image synchronously, and a computer real-time process the images, the height and pull out value can be calculate out from the images.

  2. A Neural Field Model of the Somatosensory Cortex: Formation, Maintenance and Reorganization of Ordered Topographic Maps

    PubMed Central

    Detorakis, Georgios Is.; Rougier, Nicolas P.

    2012-01-01

    We investigate the formation and maintenance of ordered topographic maps in the primary somatosensory cortex as well as the reorganization of representations after sensory deprivation or cortical lesion. We consider both the critical period (postnatal) where representations are shaped and the post-critical period where representations are maintained and possibly reorganized. We hypothesize that feed-forward thalamocortical connections are an adequate site of plasticity while cortico-cortical connections are believed to drive a competitive mechanism that is critical for learning. We model a small skin patch located on the distal phalangeal surface of a digit as a set of 256 Merkel ending complexes (MEC) that feed a computational model of the primary somatosensory cortex (area 3b). This model is a two-dimensional neural field where spatially localized solutions (a.k.a. bumps) drive cortical plasticity through a Hebbian-like learning rule. Simulations explain the initial formation of ordered representations following repetitive and random stimulations of the skin patch. Skin lesions as well as cortical lesions are also studied and results confirm the possibility to reorganize representations using the same learning rule and depending on the type of the lesion. For severe lesions, the model suggests that cortico-cortical connections may play an important role in complete recovery. PMID:22808127

  3. Somatosensory organ topography across the star of the star-nosed mole (Condylura cristata).

    PubMed

    Sawyer, Eva K; Catania, Kenneth C

    2016-04-01

    Quantifying somatosensory receptor distribution in glabrous skin is usually difficult because of the diversity of skin receptor subtypes and their location within the dermis and epidermis. However, the glabrous noses of moles are an exception. In most species of moles, the skin on the nose is covered with domed mechanosensory units known as an Eimer's organs. Eimer's organs contain a stereotyped array of different mechanosensory neurons, meaning that the distribution of mechanosensitive nerve endings can be inferred by visual inspection of the skin surface. Here we detail the distribution of Eimer's organs on the highly derived somatosensory star on the rostrum of the star-nosed mole (Condylura cristata). The star consists of 22 fleshy appendages, or rays, that are covered in Eimer's organs. We find that the density of Eimer's organs increases from proximal to distal locations along the length of the star's rays with a ratio of 1:2.3:3.1 from the surface nearest to the nostril, to the middle part of ray, to the ray tip, respectively. This ratio is comparable to the increase in receptor unit density reported for the human hand, from the palm, to the middle of the digits, to the distal fingertips. We also note that the tactile fovea of the star-nosed mole, located on the medial ventral ray, does not have increased sensory organ density, and we describe these findings in comparison with other sensory fovea.

  4. The role of self-touch in somatosensory and body representation disorders after stroke

    PubMed Central

    van Stralen, H. E.; van Zandvoort, M. J. E.; Dijkerman, H. C.

    2011-01-01

    Somatosensory impairments occur in about half of the cases of stroke. These impairments range from primary deficits in tactile detection and the perception of features, to higher order impairments in haptic object recognition and bodily experience. In this paper, we review the influence of active- and self-touch on somatosensory impairments after stroke. Studies have shown that self-touch improves tactile detection in patients with primary tactile deficits. A small number of studies concerned with the effect of self-touch on bodily experience in healthy individuals have demonstrated that self-touch influences the structural representation of one's own body. In order to better understand the effect of self-touch on body representations, we present an informal study of a stroke patient with somatoparaphrenia and misoplegia. The role of self-touch on body ownership was investigated by asking the patient to stroke the impaired left hand and foreign hands. The patient reported ownership and a change in affect over all presented hands through self-touch. The time it took to accomplish ownership varied, based on the resemblance of the foreign hand to the patient's own hand. Our findings suggest that self-touch can modulate impairments in body ownership and affect, perhaps by helping to reinstate the representation of the body. PMID:21969696

  5. Diagnostic classification of intrinsic functional connectivity highlights somatosensory, default mode, and visual regions in autism.

    PubMed

    Chen, Colleen P; Keown, Christopher L; Jahedi, Afrooz; Nair, Aarti; Pflieger, Mark E; Bailey, Barbara A; Müller, Ralph-Axel

    2015-01-01

    Despite consensus on the neurological nature of autism spectrum disorders (ASD), brain biomarkers remain unknown and diagnosis continues to be based on behavioral criteria. Growing evidence suggests that brain abnormalities in ASD occur at the level of interconnected networks; however, previous attempts using functional connectivity data for diagnostic classification have reached only moderate accuracy. We selected 252 low-motion resting-state functional MRI (rs-fMRI) scans from the Autism Brain Imaging Data Exchange (ABIDE) including typically developing (TD) and ASD participants (n = 126 each), matched for age, non-verbal IQ, and head motion. A matrix of functional connectivities between 220 functionally defined regions of interest was used for diagnostic classification, implementing several machine learning tools. While support vector machines in combination with particle swarm optimization and recursive feature elimination performed modestly (with accuracies for validation datasets <70%), diagnostic classification reached a high accuracy of 91% with random forest (RF), a nonparametric ensemble learning method. Among the 100 most informative features (connectivities), for which this peak accuracy was achieved, participation of somatosensory, default mode, visual, and subcortical regions stood out. Whereas some of these findings were expected, given previous findings of default mode abnormalities and atypical visual functioning in ASD, the prominent role of somatosensory regions was remarkable. The finding of peak accuracy for 100 interregional functional connectivities further suggests that brain biomarkers of ASD may be regionally complex and distributed, rather than localized. PMID:26106547

  6. Nociception-related somatosensory evoked potentials in awake dogs recorded after intra epidermal electrical stimulation.

    PubMed

    van Oostrom, Hugo; Stienen, Peter J; Doornenbal, Arie; Hellebrekers, Ludo J

    2009-02-01

    At present, the specific neurophysiologic methodology of recording pain-related evoked potentials is considered a most promising approach to objectively quantify pain in man. This study was designed to characterise and evaluate the use of somatosensory evoked potentials to study nociception in a canine model. To this aim, somatosensory evoked potentials were evoked by intra-epidermal electrical stimulation and recorded from the scalp in 8 beagle dogs. Characteristics determined were: (1) the conduction velocities of the peripheral nerve fibres involved, (2) the stimulus intensity response characteristics and (3) the evaluation of possible disturbance of the signals by muscular activity from the hind paw withdrawal reflex (EMG artefact). The results showed (1) the conduction velocities to be in the A-delta fibre range (i.e. fibres involved in nociception), (2) an increase in amplitude and a decrease in latency of the evoked potential following increasing stimulus intensities and (3) the absence of EMG artefact in the signals. These data indicate that the evoked potentials recorded, are related to nociception and thus are suited to quantitatively characterise the perception of noxious stimuli making this model useful for pain- and analgesia-related research.

  7. Neuronal mechanisms mediating the variability of somatosensory evoked potentials during sleep oscillations in cats

    PubMed Central

    Rosanova, Mario; Timofeev, Igor

    2005-01-01

    The slow oscillation (SO) generated within the corticothalamic system is composed of active and silent states. The studies of response variability during active versus silent network states within thalamocortical system of human and animals provided inconsistent results. To investigate this inconsistency, we used electrophysiological recordings from the main structures of the somatosensory system in anaesthetized cats. Stimulation of the median nerve (MN) elicited cortical responses during all phases of SO. Cortical responses to stimulation of the medial lemniscus (ML) were virtually absent during silent periods. At the ventral-posterior lateral (VPL) level, ML stimuli elicited either EPSPs in isolation or EPSPs crowned by spikes, as a function of membrane potential. Response to MN stimuli elicited compound synaptic responses and spiked at any physiological level of membrane potential. The responses of dorsal column nuclei neurones to MN stimuli were of similar latency, but the latencies of antidromic responses to ML stimuli were variable. Thus, the variable conductance velocity of ascending prethalamic axons was the most likely cause of the barrages of synaptic events in VPL neurones mediating their firing at different level of the membrane potential. We conclude that the preserved ability of the somatosensory system to transmit the peripheral stimuli to the cerebral cortex during all the phases of sleep slow oscillation is based on the functional properties of the medial lemniscus and on the intrinsic properties of the thalamocortical cells. However the reduced firing ability of the cortical neurones during the silent state may contribute to impair sensory processing during sleep. PMID:15528249

  8. Single-unit Analysis of Somatosensory Processing in Core Auditory Cortex of Hearing Ferrets

    PubMed Central

    Meredith, M. Alex; Allman, Brian L.

    2014-01-01

    The recent findings in several species that primary auditory cortex processes non-auditory information have largely overlooked the possibility for somatosensory effects. Therefore, the present investigation examined the core auditory cortices (anterior – AAF, and primary auditory-- A1, fields) for tactile responsivity. Multiple single-unit recordings from anesthetized ferret cortex yielded histologically verified neurons (n=311) tested with electronically controlled auditory, visual and tactile stimuli and their combinations. Of the auditory neurons tested, a small proportion (17%) was influenced by visual cues, but a somewhat larger number (23%) was affected by tactile stimulation. Tactile effects rarely occurred alone and spiking responses were observed in bimodal auditory-tactile neurons. However, the broadest tactile effect that was observed, which occurred in all neuron types, was that of suppression of the response to a concurrent auditory cue. The presence of tactile effects in core auditory cortices was supported by a substantial anatomical projection from the rostral suprasylvian sulcal somatosensory area. Collectively, these results demonstrate that crossmodal effects in auditory cortex are not exclusively visual and that somatosensation plays a significant role in modulation of acoustic processing and indicate that crossmodal plasticity following deafness may unmask these existing non-auditory functions. PMID:25728185

  9. Understanding the link between somatosensory temporal discrimination and movement execution in healthy subjects.

    PubMed

    Conte, Antonella; Belvisi, Daniele; Manzo, Nicoletta; Bologna, Matteo; Barone, Francesca; Tartaglia, Matteo; Upadhyay, Neeraj; Berardelli, Alfredo

    2016-09-01

    The somatosensory temporal discrimination threshold (STDT) is the shortest interval at which an individual recognizes paired stimuli as separate in time. We investigated whether and how voluntary movement modulates STDT in healthy subjects. In 17 healthy participants, we tested STDT during voluntary index-finger abductions at several time-points after movement onset and during motor preparation. We then tested whether voluntary movement-induced STDT changes were specific for the body segment moved, depended on movement kinematics, on the type of movement or on the intensity for delivering paired electrical stimuli for STDT To understand the mechanisms underlying STDT modulation, we also tested STDT during motor imagery and after delivering repetitive transcranial magnetic stimulation to elicit excitability changes in the primary somatosensory cortex (S1). When tested on the moving hand at movement onset and up to 200 msec thereafter, STDT values increased from baseline, but during motor preparation remained unchanged. STDT values changed significantly during fast and slow index-finger movements and also, though less, during passive index-finger abductions, whereas during tonic index-finger abductions they remained unchanged. STDT also remained unchanged when tested in body parts other than those engaged in movement and during imagined movement. Nor did testing STDT at increased intensity influence movement-induced STDT changes. The cTBS-induced S1 cortical changes left movement-induced STDT changes unaffected. Our findings suggest that movement execution in healthy subjects may alter STDT processing. PMID:27650249

  10. The assessment of somatosensory cortex plasticity during sleep deprivation by paired associative stimulation.

    PubMed

    Gorgoni, Maurizio; Ferlazzo, Fabio; D'Atri, Aurora; Lauri, Giulia; Ferrara, Michele; Rossini, Paolo Maria; De Gennaro, Luigi

    2015-01-01

    Many animal studies suggest that during sleep deprivation (SD) synaptic strength should progressively increase, leading to the saturation of the ability to induce long-term potentiation (LTP). Nevertheless, direct evidences about the effects of sustained wakefulness on cortical plasticity in humans are still lacking. The aim of the present study was to assess changes in the ability to induce LTP-like mechanism in humans during a period of SD by means of a paired associative stimulation (PAS) protocol, which combines median nerve stimulation with transcranial magnetic stimulation (TMS) applied over the contralateral somatosensory cortex. During a 41-h SD protocol, 16 healthy subjects, defined as responders to the PAS protocol after a pre-selection session, were involved in 4 experimental sessions (11.00 a.m. and 11.00 p.m. of first and second day) with: a) pre-PAS somatosensory evoked potentials (SEPs) recordings; b) PAS protocol; c) post-PAS SEPs recordings. The effect of PAS on SEPs early components (N20-P25 complex) was assessed. During the first experimental session (without SD) no significant PAS effects on SEPs components amplitude have been found, and large intra- and inter-individual variability have been observed. A lack of significant changes has been observed also in the subsequent sessions. Our results index a low intra- and inter-individual reliability of the PAS protocol, suggesting particular caution when longitudinally evaluating the effect of this technique on cortical plasticity. PMID:26742665

  11. Hypnotically induced somatosensory alterations: Toward a neurophysiological understanding of hypnotic anaesthesia.

    PubMed

    Zeev-Wolf, Maor; Goldstein, Abraham; Bonne, Omer; Abramowitz, Eitan G

    2016-07-01

    Whereas numerous studies have investigated hypnotic analgesia, few have investigated hypnotic anaesthesia. Using magnetoencephalography (MEG) we investigated and localized brain responses (event-related fields and oscillatory activity) during sensory processing under hypnotic anaesthesia. Nineteen right handed neurotypical individuals with moderate-to-high hypnotizability received 100 vibrotactile stimuli to right and left index fingers in a random sequence. Thereafter a hypnotic state was induced, in which anaesthetic suggestion was applied to the left hand only. Once anaesthetic suggestion was achieved, a second, identical, session of vibrotactile stimuli was commenced. We found greater brain activity in response to the stimuli delivered to the left (attenuated) hand before hypnotic anaesthesia, than under hypnotic anaesthesia, in both the beta and alpha bands. In the beta band, the reduction of activity under hypnotic anaesthesia was found around 214-413ms post-stimuli and was located mainly in the right insula. In the alpha band, it was found around 253-500ms post-stimuli and was located mainly in the left inferior frontal gyrus. In a second experiment, attention modulation per se was ruled out as the underlying cause of the effects found. These findings may suggest that the brain mechanism underlying hypnotic anaesthesia involves top-down somatosensory inhibition and, therefore, a reduction of somatosensory awareness. The result of this mechanism is a mental state in which individuals lose bodily sensation. PMID:27212058

  12. Task-relevant modulation of primary somatosensory cortex suggests a prefrontal-cortical sensory gating system.

    PubMed

    Schaefer, Michael; Heinze, Hans-Jochen; Rotte, Michael

    2005-08-01

    Increasing evidence suggests that somatosensory information is modulated cortically for task-specific sensory inflow: Several studies report short-term adaptation of representational maps in primary somatosensory cortex (SI) due to attention or induced by task-related motor activity such as handwriting. Recently, it has been hypothesized that the frontal or prefrontal cortex may modulate SI. In order to test this hypothesis, we studied the functional organization of SI while subjects performed the Tower of Hanoi task. This task is known to be related to activation of frontal or prefrontal areas. The functional organization of SI while performing the Tower of Hanoi task was compared to the organization of SI during performing the same movements but without the Tower of Hanoi task and with rest. Topography of SI was assessed using neuromagnetic source imaging based on tactile stimulation of the first (D1) and fifth digits (D5). Performing the Tower of Hanoi task was accompanied by plastic changes in SI as indicated by significant shifts in the cortical representations of D1 and D5: They moved further apart during the Tower of Hanoi task compared to the control task containing the same movements but without the cognitive characteristic. Thus, we conclude that SI maps undergo dynamic modulation depending on motor tasks with different cognitive demands. The results suggest that this short-term plasticity may be regulated by a prefrontal-cortical sensory gating system. PMID:15886021

  13. Transcriptional profiling at whole population and single cell levels reveals somatosensory neuron molecular diversity

    PubMed Central

    Chiu, Isaac M; Barrett, Lee B; Williams, Erika K; Strochlic, David E; Lee, Seungkyu; Weyer, Andy D; Lou, Shan; Bryman, Gregory S; Roberson, David P; Ghasemlou, Nader; Piccoli, Cara; Ahat, Ezgi; Wang, Victor; Cobos, Enrique J; Stucky, Cheryl L; Ma, Qiufu; Liberles, Stephen D; Woolf, Clifford J

    2014-01-01

    The somatosensory nervous system is critical for the organism's ability to respond to mechanical, thermal, and nociceptive stimuli. Somatosensory neurons are functionally and anatomically diverse but their molecular profiles are not well-defined. Here, we used transcriptional profiling to analyze the detailed molecular signatures of dorsal root ganglion (DRG) sensory neurons. We used two mouse reporter lines and surface IB4 labeling to purify three major non-overlapping classes of neurons: 1) IB4+SNS-Cre/TdTomato+, 2) IB4−SNS-Cre/TdTomato+, and 3) Parv-Cre/TdTomato+ cells, encompassing the majority of nociceptive, pruriceptive, and proprioceptive neurons. These neurons displayed distinct expression patterns of ion channels, transcription factors, and GPCRs. Highly parallel qRT-PCR analysis of 334 single neurons selected by membership of the three populations demonstrated further diversity, with unbiased clustering analysis identifying six distinct subgroups. These data significantly increase our knowledge of the molecular identities of known DRG populations and uncover potentially novel subsets, revealing the complexity and diversity of those neurons underlying somatosensation. DOI: http://dx.doi.org/10.7554/eLife.04660.001 PMID:25525749

  14. Reconciling Homeostatic and Use-Dependent Plasticity in the Context of Somatosensory Deprivation

    PubMed Central

    Orczyk, John J.; Garraghty, Preston E.

    2015-01-01

    The concept of homeostatic plasticity postulates that neurons maintain relatively stable rates of firing despite changing inputs. Homeostatic and use-dependent plasticity mechanisms operate concurrently, although they have different requirements for induction. Depriving central somatosensory neurons of their primary activating inputs reduces activity and results in compensatory changes that favor excitation. Both a reduction of GABAergic inhibition and increase in glutamatergic excitatory transmission are observed in input-deprived cortex. Topographic reorganization of the adult somatosensory cortex is likely driven by both homeostatic and use-dependent mechanisms. Plasticity is induced by changes in the strengths of synaptic inputs, as well as changes in temporal correlation of neuronal activity. However, there is less certainty regarding the in vivo contribution of homeostatic mechanisms as in vitro experiments rely on manipulations that create states that do not normally occur in the living nervous system. Homeostatic plasticity seems to occur, but more in vivo research is needed to determine mechanisms. In vitro research is also needed but should better conform to conditions that might occur naturally in vivo. PMID:25866682

  15. Cortical EEG alpha rhythms reflect task-specific somatosensory and motor interactions in humans.

    PubMed

    Babiloni, Claudio; Del Percio, Claudio; Arendt-Nielsen, Lars; Soricelli, Andrea; Romani, Gian Luca; Rossini, Paolo Maria; Capotosto, Paolo

    2014-10-01

    Anticipating sensorimotor events allows adaptive reactions to environment with crucial implications for self-protection and survival. Here we review several studies of our group that aimed to test the hypothesis that the cortical processes preparing the elaboration of sensorimotor interaction is reflected by the reduction of anticipatory electroencephalographic alpha power (about 8-12Hz; event-related desynchronization, ERD), as an index that regulate task-specific sensorimotor processes, accounted by high-alpha sub-band (10-12Hz), rather than a general tonic alertness, accounted by low-alpha sub-band (8-10Hz). In this line, we propose a model for human cortical processes anticipating warned sensorimotor interactions. Overall, we reported a stronger high-alpha ERD before painful than non-painful somatosensory stimuli that is also predictive of the subjective evaluation of pain intensity. Furthermore, we showed that anticipatory high-alpha ERD increased before sensorimotor interactions between non-painful or painful stimuli and motor demands involving opposite hands. In contrast, sensorimotor interactions between painful somatosensory and sensorimotor demands involving the same hand decreased anticipatory high-alpha ERD, due to a sort of sensorimotor "gating" effect. In conclusion, we suggest that anticipatory cortical high-alpha rhythms reflect the central interference and/or integration of ascending (sensory) and descending (motor) signals relative to one or two hands before non-painful and painful sensorimotor interactions. PMID:24929901

  16. Estimation of phase signal change in neuronal current MRI for evoke response of tactile detection with realistic somatosensory laminar network model.

    PubMed

    BagheriMofidi, Seyed Mehdi; Pouladian, Majid; Jameie, Seyed Behnamedin; Abbaspour Tehrani-Fard, Ali

    2016-09-01

    Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot-savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm(3). With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.

  17. Estimation of phase signal change in neuronal current MRI for evoke response of tactile detection with realistic somatosensory laminar network model.

    PubMed

    BagheriMofidi, Seyed Mehdi; Pouladian, Majid; Jameie, Seyed Behnamedin; Abbaspour Tehrani-Fard, Ali

    2016-09-01

    Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot-savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm(3). With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. PMID:27585451

  18. [Contact dermatitis in Dakar].

    PubMed

    Niang, S O

    2007-01-01

    Because of the widespread repartition of allergens, allergic contact dermatitis is the most common inflammatory skin disease. It's the best model of dilated hypersensibility mediated by T lymphocytes cells. Atopic dermatitis and irritative dermatitis are to be distinguished to contact dermatitis. The aetiological diagnosis is the most important step of management of patients with that disease because it's the best way to avoid recurrences. The identification of cause is based on aetiological interrogatory and epicutaneous tests with 23 allergens completed with personnel products and specialised tests. Contact dermatitis can be classified according to results of aetiological management. In occupational contact dermatitis, contact dermatitis due to drugs, to metals, cosmetics, clothes and accessory and proteins. Management of patients with contact dermatitis is based on individual eviction, protection, cosmetovigilance, declaration of occupational dermatosis and allergovigilance. PMID:19102084

  19. Dynamic contact angle measurements on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.

    2015-03-01

    In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, θD3 ∝ Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at θA = 160∘, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.

  20. Optical contact micrometer

    SciTech Connect

    Jacobson, Steven D.

    2014-08-19

    Certain examples provide optical contact micrometers and methods of use. An example optical contact micrometer includes a pair of opposable lenses to receive an object and immobilize the object in a position. The example optical contact micrometer includes a pair of opposable mirrors positioned with respect to the pair of lenses to facilitate viewing of the object through the lenses. The example optical contact micrometer includes a microscope to facilitate viewing of the object through the lenses via the mirrors; and an interferometer to obtain one or more measurements of the object.

  1. Intraoperative somatosensory evoked potential recovery following opening of the fourth ventricle during posterior fossa decompression in Chiari malformation: case report.

    PubMed

    Grossauer, Stefan; Koeck, Katharina; Vince, Giles H

    2015-03-01

    The most appropriate surgical technique for posterior fossa decompression in Chiari malformation (CM) remains a matter of debate. Intraoperative electrophysiological studies during posterior fossa decompression of Type I CM (CM-I) aim to shed light on the entity's pathomechanism as well as on the ideal extent of decompression. The existing reports on this issue state that significant improvement in conduction occurs after craniotomy in all cases, but additional durotomy contributes a further improvement in only a minority of cases. This implies that craniotomy alone might suffice for clinical improvement without the need of duraplasty or even subarachnoid manipulation at the level of the craniocervical junction. In contrast to published data, the authors describe the case of a 32-year-old woman who underwent surgery for CM associated with extensive cervicothoracic syringomyelia and whose intraoperative somatosensory evoked potentials (SSEPs) did not notably improve after craniotomy or following durotomy; rather, they only improved after opening of the fourth ventricle and restoration of CSF flow through the foramen of Magendie. Postoperatively, the patient recovered completely from her preoperative neurological deficits. To the authors' knowledge, this is the first report of significant SSEP recovery after opening the fourth ventricle in the decompression of a CM-I. The electrophysiological and operative techniques are described in detail and the findings are discussed in the light of available literature. The authors conclude that there might be a subset of CM-I patients who require subarachnoid dissection at the level of the craniocervical junction to benefit clinically. Prospective studies with detailed electrophysiological analyses seem warranted to answer the question regarding the best surgical approach in CM-I decompression.

  2. Experience-dependent changes in spatiotemporal properties of cutaneous inputs remodel somatosensory cortical maps following skin flap rotation.

    PubMed

    Rosselet, Céline; Zennou-Azogui, Yoh'i; Escoffier, Guy; Kirmaci, Fatma; Xerri, Christian

    2008-03-01

    Contiguous skin surfaces that tend to be synchronously stimulated are represented in neighbouring sectors of primary somatosensory maps. Moreover, neuronal receptive fields (RFs) are reshaped through ongoing competitive/cooperative interactions that segregate/desegregate inputs converging onto cortical neuronal targets. The present study was designed to evaluate the influence of spatio-temporal constraints on somatotopic map organization. A vascularized and innervated pedicle flap of the ventrum skin bearing nipples was rotated by 180 degrees . Electrophysiological maps of ventrum skin were elaborated in the same rats at 24 h after surgery and 2 weeks after parturition. Neurones with split RFs resulting from the surgical separation of formerly adjoining skin surfaces were more numerous in non-nursing than nursing rats. RFs that included newly adjacent skin surfaces on both sides of the scar line emerged in nursing rats, suggesting that the spatial contiguity of formerly separated skin surfaces induced a fusion of their cortical representations through nursing-induced stimulation. In addition, nursing-dependent inputs were found to reincorporate the rotated skin flap representation in an updated topographical organization of the cortical map. A skin territory including recipient and translocated skin areas was costimulated for 7 h, using a brushing device. Neural responses evoked by a piezoelectric-induced skin indentation before and after skin brushing confirmed the emergence of RFs crossing the scar line and contraction of non-brushed components of split RFs. Our findings provide further evidence that the spatiotemporal structure of sensory inputs changing rapidly or evolving in a natural context is critical for experience-dependent reorganization of cortical map topography. PMID:18312588

  3. Phosphazene additives

    DOEpatents

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  4. Potlining Additives

    SciTech Connect

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  5. Detection of optogenetic stimulation in somatosensory cortex by non-human primates--towards artificial tactile sensation.

    PubMed

    May, Travis; Ozden, Ilker; Brush, Benjamin; Borton, David; Wagner, Fabien; Agha, Naubahar; Sheinberg, David L; Nurmikko, Arto V

    2014-01-01

    Neuroprosthesis research aims to enable communication between the brain and external assistive devices while restoring lost functionality such as occurs from stroke, spinal cord injury or neurodegenerative diseases. In future closed-loop sensorimotor prostheses, one approach is to use neuromodulation as direct stimulus to the brain to compensate for a lost sensory function and help the brain to integrate relevant information for commanding external devices via, e.g. movement intention. Current neuromodulation techniques rely mainly of electrical stimulation. Here we focus specifically on the question of eliciting a biomimetically relevant sense of touch by direct stimulus of the somatosensory cortex by introducing optogenetic techniques as an alternative to electrical stimulation. We demonstrate that light activated opsins can be introduced to target neurons in the somatosensory cortex of non-human primates and be optically activated to create a reliably detected sensation which the animal learns to interpret as a tactile sensation localized within the hand. The accomplishment highlighted here shows how optical stimulation of a relatively small group of mostly excitatory somatosensory neurons in the nonhuman primate brain is sufficient for eliciting a useful sensation from data acquired by simultaneous electrophysiology and from behavioral metrics. In this first report to date on optically neuromodulated behavior in the somatosensory cortex of nonhuman primates we do not yet dissect the details of the sensation the animals exerience or contrast it to those evoked by electrical stimulation, issues of considerable future interest.

  6. Visual Responsiveness of Neurons in the Secondary Somatosensory Area and its Surrounding Parietal Operculum Regions in Awake Macaque Monkeys

    PubMed Central

    Hihara, Sayaka; Taoka, Miki; Tanaka, Michio; Iriki, Atsushi

    2015-01-01

    Previous neurophysiological studies performed in macaque monkeys have shown that the secondary somatosensory cortex (SII) is essentially engaged in the processing of somatosensory information and no other sensory input has been reported. In contrast, recent human brain-imaging studies have revealed the effects of visual and auditory stimuli on SII activity, which suggest multisensory integration in the human SII. To determine whether multisensory responses of the SII also exist in nonhuman primates, we recorded single-unit activity in response to visual and auditory stimuli from the SII and surrounding regions in 8 hemispheres from 6 awake monkeys. Among 1157 recorded neurons, 306 neurons responded to visual stimuli. These visual neurons usually responded to rather complex stimuli, such as stimulation of the peripersonal space (40.5%), observation of human action (29.1%), and moving-object stimulation outside the monkey's reach (23.9%). We occasionally applied auditory stimuli to visual neurons and found 10 auditory-responsive neurons that exhibited somatosensory responses. The visual neurons were distributed continuously along the lateral sulcus covering the entire SII, along with other somatosensory neurons. These results highlight the need to investigate novel functional roles—other than somesthetic sensory processing—of the SII. PMID:25962920

  7. Visual Responsiveness of Neurons in the Secondary Somatosensory Area and its Surrounding Parietal Operculum Regions in Awake Macaque Monkeys.

    PubMed

    Hihara, Sayaka; Taoka, Miki; Tanaka, Michio; Iriki, Atsushi

    2015-11-01

    Previous neurophysiological studies performed in macaque monkeys have shown that the secondary somatosensory cortex (SII) is essentially engaged in the processing of somatosensory information and no other sensory input has been reported. In contrast, recent human brain-imaging studies have revealed the effects of visual and auditory stimuli on SII activity, which suggest multisensory integration in the human SII. To determine whether multisensory responses of the SII also exist in nonhuman primates, we recorded single-unit activity in response to visual and auditory stimuli from the SII and surrounding regions in 8 hemispheres from 6 awake monkeys. Among 1157 recorded neurons, 306 neurons responded to visual stimuli. These visual neurons usually responded to rather complex stimuli, such as stimulation of the peripersonal space (40.5%), observation of human action (29.1%), and moving-object stimulation outside the monkey's reach (23.9%). We occasionally applied auditory stimuli to visual neurons and found 10 auditory-responsive neurons that exhibited somatosensory responses. The visual neurons were distributed continuously along the lateral sulcus covering the entire SII, along with other somatosensory neurons. These results highlight the need to investigate novel functional roles-other than somesthetic sensory processing-of the SII.

  8. Effects of Improvement on Selective Attention: Developing Appropriate Somatosensory Video Game Interventions for Institutional-Dwelling Elderly with Disabilities

    ERIC Educational Resources Information Center

    Chen, Shang-Ti; Chiang, I-Tsun; Liu, Eric Zhi-Feng; Chang, Maiga

    2012-01-01

    The purpose of this study was to develop appropriate somatosensory video game interventions on enhancing selective attention of institutional-dwelling elderly with disabilities. Fifty-eight participants aged 65[approximately]92 were recruited and divided into four groups, 4-week and 8-week experimental and two control groups, for evaluating the…

  9. Language Contact: An Introduction.

    ERIC Educational Resources Information Center

    Thomason, Sarah G.

    This book surveys situations in which language contact arises and focuses on what happens to the languages themselves: sometimes nothing, sometimes the incorporation of new words, sometimes the spread of new sounds and sentence structures across many languages and wide swathes of territory. It outlines the origins and results of contact-induced…

  10. Calmodulin Methyltransferase Is Required for Growth, Muscle Strength, Somatosensory Development and Brain Function.

    PubMed

    Haziza, Sitvanit; Magnani, Roberta; Lan, Dima; Keinan, Omer; Saada, Ann; Hershkovitz, Eli; Yanay, Nurit; Cohen, Yoram; Nevo, Yoram; Houtz, Robert L; Sheffield, Val C; Golan, Hava; Parvari, Ruti

    2015-08-01

    Calmodulin lysine methyl transferase (CaM KMT) is ubiquitously expressed and highly conserved from plants to vertebrates. CaM is frequently trimethylated at Lys-115, however, the role of CaM methylation in vertebrates has not been studied. CaM KMT was found to be homozygously deleted in the 2P21 deletion syndrome that includes 4 genes. These patients present with cystinuria, severe intellectual disabilities, hypotonia, mitochondrial disease and facial dysmorphism. Two siblings with deletion of three of the genes included in the 2P21 deletion syndrome presented with cystinuria, hypotonia, a mild/moderate mental retardation and a respiratory chain complex IV deficiency. To be able to attribute the functional significance of the methylation of CaM in the mouse and the contribution of CaM KMT to the clinical presentation of the 2p21deletion patients, we produced a mouse model lacking only CaM KMT with deletion borders as in the human 2p21deletion syndrome. No compensatory activity for CaM methylation was found. Impairment of complexes I and IV, and less significantly III, of the mitochondrial respiratory chain was more pronounced in the brain than in muscle. CaM KMT is essential for normal body growth and somatosensory development, as well as for the proper functioning of the adult mouse brain. Developmental delay was demonstrated for somatosensory function and for complex behavior, which involved both basal motor function and motivation. The mutant mice also had deficits in motor learning, complex coordination and learning of aversive stimuli. The mouse model contributes to the evaluation of the role of methylated CaM. CaM methylation appears to have a role in growth, muscle strength, somatosensory development and brain function. The current study has clinical implications for human patients. Patients presenting slow growth and muscle weakness that could result from a mitochondrial impairment and mental retardation should be considered for sequence analysis of the Ca

  11. Co-occurrence of Pain Symptoms and Somatosensory Sensitivity in Burning Mouth Syndrome: A Systematic Review

    PubMed Central

    Moisset, Xavier; Calbacho, Valentina; Torres, Pilar; Gremeau-Richard, Christelle; Dallel, Radhouane

    2016-01-01

    Background Burning mouth syndrome (BMS) is a chronic and spontaneous oral pain with burning quality in the tongue or other oral mucosa without any identifiable oral lesion or laboratory finding. Pathogenesis and etiology of BMS are still unknown. However, BMS has been associated with other chronic pain syndromes including other idiopathic orofacial pain, the dynias group and the family of central sensitivity syndromes. This would imply that BMS shares common mechanisms with other cephalic and/or extracephalic chronic pains. The primary aim of this systematic review was to determine whether BMS is actually associated with other pain syndromes, and to analyze cephalic and extracephalic somatosensory sensitivity in these patients. Methods This report followed the PRISMA Statement. An electronic search was performed until January 2015 in PubMed, Cochrane library, Wiley and ScienceDirect. Searched terms included “burning mouth syndrome OR stomatodynia OR glossodynia OR burning tongue OR oral burning”. Studies were selected according to predefined inclusion criteria (report of an association between BMS and other pain(s) symptoms or of cutaneous cephalic and/or extracephalic quantitative sensory testing in BMS patients), and a descriptive analysis conducted. Results The search retrieved 1512 reports. Out of these, twelve articles met criteria for co-occurring pain symptoms and nine studies for quantitative sensory testing (QST) in BMS patients. The analysis reveals that in BMS patients co-occurring pain symptoms are rare, assessed by only 0.8% (12 of 1512) of the retrieved studies. BMS was associated with headaches, TMD, atypical facial pain, trigeminal neuralgia, post-herpetic facial pain, back pain, fibromyalgia, joint pain, abdominal pain, rectal pain or vulvodynia. However, the prevalence of pain symptoms in BMS patients is not different from that in the age-matched general population. QST studies reveal no or inconsistent evidence of abnormal cutaneous cephalic

  12. Calmodulin Methyltransferase Is Required for Growth, Muscle Strength, Somatosensory Development and Brain Function

    PubMed Central

    Haziza, Sitvanit; Magnani, Roberta; Lan, Dima; Keinan, Omer; Saada, Ann; Hershkovitz, Eli; Yanay, Nurit; Cohen, Yoram; Nevo, Yoram; Houtz, Robert L.; Sheffield, Val C.; Golan, Hava; Parvari, Ruti

    2015-01-01

    Calmodulin lysine methyl transferase (CaM KMT) is ubiquitously expressed and highly conserved from plants to vertebrates. CaM is frequently trimethylated at Lys-115, however, the role of CaM methylation in vertebrates has not been studied. CaM KMT was found to be homozygously deleted in the 2P21 deletion syndrome that includes 4 genes. These patients present with cystinuria, severe intellectual disabilities, hypotonia, mitochondrial disease and facial dysmorphism. Two siblings with deletion of three of the genes included in the 2P21 deletion syndrome presented with cystinuria, hypotonia, a mild/moderate mental retardation and a respiratory chain complex IV deficiency. To be able to attribute the functional significance of the methylation of CaM in the mouse and the contribution of CaM KMT to the clinical presentation of the 2p21deletion patients, we produced a mouse model lacking only CaM KMT with deletion borders as in the human 2p21deletion syndrome. No compensatory activity for CaM methylation was found. Impairment of complexes I and IV, and less significantly III, of the mitochondrial respiratory chain was more pronounced in the brain than in muscle. CaM KMT is essential for normal body growth and somatosensory development, as well as for the proper functioning of the adult mouse brain. Developmental delay was demonstrated for somatosensory function and for complex behavior, which involved both basal motor function and motivation. The mutant mice also had deficits in motor learning, complex coordination and learning of aversive stimuli. The mouse model contributes to the evaluation of the role of methylated CaM. CaM methylation appears to have a role in growth, muscle strength, somatosensory development and brain function. The current study has clinical implications for human patients. Patients presenting slow growth and muscle weakness that could result from a mitochondrial impairment and mental retardation should be considered for sequence analysis of the Ca

  13. Somatosensory Amplification, Anxiety, and Depression in Patients With Hepatitis B: Impact on Functionality

    PubMed Central

    Yilmaz, Ahmet; Ucmak, Feyzullah; Dönmezdil, Süleyman; Kaya, Mehmet Cemal; Tekin, Recep; Günes, Mehmet; Arslan, Necmi; Bulut, Mahmut

    2016-01-01

    Abstract In the present study, we aimed to determine the differences in body image along with anxiety and depression levels, and also to evaluate their impact on disability parameters in patients with hepatitis B. Our study comprised 77 patients with hepatitis B (n = 41, chronic active patients; n = 36, patients with inactive hepatitis B) and 53 healthy individuals (control group). Enrolled patients responded to several questionnaires, including a sociodemographic form, Sheehan Disability Scale (SDS), Hospital Anxiety and Depression Scale (HADS), and Somatosensory Amplification Scale. Patients with chronic active hepatitis B (CAHB) had higher levels of somatosensory perception than patients with inactive hepatitis B (IHB) and control group (P < 0.001, P = 0.001, respectively). Patients with CAHB had high scores on all the 3 domains of SDS (work/school, P < 0.001; social life, P < 0.001; and family life, P < 0.001). Also, patients with CAHB had a significantly higher HADS total score, HADS anxiety score, and HADS depression score than control group (P < 0.001, P < 0.001, P < 0.001, respectively). No significant difference was noted between patients with CAHB and patients with IHB with regard to HADS depression score; however, HADS anxiety and HADS total scores were significantly higher in the CAHB group (NS, P = 0.027, P = 0.035, respectively). Moreover, the IHB group exhibited higher scores for the work/school and social life domains of SDS than those of the control group (P = 0.008, P = 0.047). Although patients with CAHB may present with somatosensory amplification, anxiety, and depression, patients with IHB do not exhibit such symptoms. However, functionality is affected in both carrier and active patient groups. We believe that routine health checks of patients with hepatitis B should include psychiatric evaluation, psychiatric examination, and follow-up. PMID:27227947

  14. Noneczematous Contact Dermatitis

    PubMed Central

    Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

    2013-01-01

    Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents. PMID:24109520

  15. Contact dermatitis in athletes.

    PubMed

    Kockentiet, Brett; Adams, Brian B

    2007-06-01

    Athletes face numerous hazards in their daily activities. An athlete's skin, in particular, endures repeated exposure to trauma, heat, moisture, and numerous allergens and chemicals. These factors combine with other unique and less well-defined genetically predisposing factors in the athlete's skin to cause both allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD). As with other cases of contact dermatitis, these eruptions in athletes present as a spectrum of acute to subacute to chronic dermatitis. Recognizing the unique environmental irritants and allergens encountered by athletes is paramount to facilitate appropriate therapy and prevention. This review comprehensively examines the literature on contact dermatitis in athletes. The different types of contact dermatitis have been classified under sport-specific subheadings. Furthermore, within each subheading, both ACD and ICD types are discussed.

  16. Contact symmetries and Hamiltonian thermodynamics

    SciTech Connect

    Bravetti, A.; Lopez-Monsalvo, C.S.; Nettel, F.

    2015-10-15

    It has been shown that contact geometry is the proper framework underlying classical thermodynamics and that thermodynamic fluctuations are captured by an additional metric structure related to Fisher’s Information Matrix. In this work we analyse several unaddressed aspects about the application of contact and metric geometry to thermodynamics. We consider here the Thermodynamic Phase Space and start by investigating the role of gauge transformations and Legendre symmetries for metric contact manifolds and their significance in thermodynamics. Then we present a novel mathematical characterization of first order phase transitions as equilibrium processes on the Thermodynamic Phase Space for which the Legendre symmetry is broken. Moreover, we use contact Hamiltonian dynamics to represent thermodynamic processes in a way that resembles the classical Hamiltonian formulation of conservative mechanics and we show that the relevant Hamiltonian coincides with the irreversible entropy production along thermodynamic processes. Therefore, we use such property to give a geometric definition of thermodynamically admissible fluctuations according to the Second Law of thermodynamics. Finally, we show that the length of a curve describing a thermodynamic process measures its entropy production.

  17. [Patch-testing methods: additional specialised or additional series].

    PubMed

    Cleenewerck, M-B

    2009-01-01

    The tests in the European standard battery must occasionally be supplemented by specialised or additional batteries, particularly where the contact allergy is thought to be of occupational origin. These additional batteries cover all allergens associated with various professional activities (hairdressing, baking, dentistry, printing, etc.) and with different classes of materials and chemical products (glue, plastic, rubber...). These additional tests may also include personal items used by patients on a daily basis such as cosmetics, shoes, plants, textiles and so on.

  18. BISON Contact Improvements CASL FY14 Report

    SciTech Connect

    B. W. Spencer; J. D. Hales; D. R. Gaston; D. A. Karpeev; R. L. Williamson; S. R. Novascone; D. M. Perez; R. J. Gardner; K. A. Gamble

    2014-09-01

    The BISON code is the foundation for multiple fuel performance modeling efforts, and is cur- rently under heavy development. For a variety of fuel forms, the effects of heat conduction across a gap and mechanical contact between components of a fuel system are very significant. It is thus critical that BISON have robust capabilities for enforcement of thermal and mechanical contact. BISON’s solver robustness has generally been quite good before mechanical contact between the fuel and cladding occurs, but there have been significant challenges obtaining converged so- lutions once that contact occurs and the solver begins to enforce mechanical contact constraints. During the current year, significant development effort has been focused on the enforcement of mechanical contact to provide improved solution robustness. In addition to this work to improve mechanical contact robustness, an investigation into ques- tionable results attributable to thermal contact has been performed. This investigation found that the order of integration typically used on the surfaces involved in thermal contact was not suffi- ciently high. To address this problem, a new option was provided to permit the use of a different integration order for surfaces, and new usage recommendations were provided.

  19. Steady-State Somatosensory Evoked Potential for Brain-Computer Interface—Present and Future

    PubMed Central

    Ahn, Sangtae; Kim, Kiwoong; Jun, Sung Chan

    2016-01-01

    Brain-computer interface (BCI) performance has achieved continued improvement over recent decades, and sensorimotor rhythm-based BCIs that use motor function have been popular subjects of investigation. However, it remains problematic to introduce them to the public market because of their low reliability. As an alternative resolution to this issue, visual-based BCIs that use P300 or steady-state visually evoked potentials (SSVEPs) seem promising; however, the inherent visual fatigue that occurs with these BCIs may be unavoidable. For these reasons, steady-state somatosensory evoked potential (SSSEP) BCIs, which are based on tactile selective attention, have gained increasing attention recently. These may reduce the fatigue induced by visual attention and overcome the low reliability of motor activity. In this literature survey, recent findings on SSSEP and its methodological uses in BCI are reviewed. Further, existing limitations of SSSEP BCI and potential future directions for the technique are discussed. PMID:26834611

  20. Dendritic branching angles of pyramidal cells across layers of the juvenile rat somatosensory cortex.

    PubMed

    Leguey, Ignacio; Bielza, Concha; Larrañaga, Pedro; Kastanauskaite, Asta; Rojo, Concepción; Benavides-Piccione, Ruth; DeFelipe, Javier

    2016-09-01

    The characterization of the structural design of cortical microcircuits is essential for understanding how they contribute to function in both health and disease. Since pyramidal neurons represent the most abundant neuronal type and their dendritic spines constitute the major postsynaptic elements of cortical excitatory synapses, our understanding of the synaptic organization of the neocortex largely depends on the available knowledge regarding the structure of pyramidal cells. Previous studies have identified several apparently common rules in dendritic geometry. We study the dendritic branching angles of pyramidal cells across layers to further shed light on the principles that determine the geometric shapes of these cells. We find that the dendritic branching angles of pyramidal cells from layers II-VI of the juvenile rat somatosensory cortex suggest common design principles, despite the particular morphological and functional features that are characteristic of pyramidal cells in each cortical layer. J. Comp. Neurol. 524:2567-2576, 2016. © 2016 Wiley Periodicals, Inc.

  1. The effects of halothane on somatosensory and flash visual evoked potentials during operations.

    PubMed

    Wang, A D; Costa e Silva, I; Symon, L; Jewkes, D

    1985-06-01

    Intraoperative use of somatosensory evoked potentials (SEP's) to monitor intracranial aneurysm surgery and flash visual evoked potentials (F-VEP's) for parasellar surgery have been routinely employed in our clinic. We found that both EP modalities are sensitive to the changing concentration of our standard hypotensive agent, halothane. The prolongation of the N14-N20 interpeak latency to median nerve stimulation at the wrist, and prolongation of P100 latency with altered configuration of early VEP components to flash light stimulation, appear to be the results of direct pharmacological effects of the agent and not an effect of secondary hypotension. VEP is found easily abolished by halothane at a concentration of 2.0%, while the SEP is more resistant. Halothane is not ideal however when monitoring intraoperative VEP.

  2. Early somatosensory event-related potentials reveal attentional bias for internal stimuli in social anxiety.

    PubMed

    Kanai, Yoshihiro; Nittono, Hiroshi; Kubo, Kenta; Sasaki-Aoki, Shoko; Iwanaga, Makoto

    2012-03-01

    The present study used event-related brain potentials (ERPs) to investigate allocation of attentional resources to internal and external stimuli in individuals with social anxiety. High and low socially anxious individuals were presented with depictions of various facial expressions or household objects, followed by an internal (vibration presented to the finger) or external probe (the letter "E"). Participants were told that the vibration signals physiological changes and were asked to detect both probes. High socially anxious individuals showed larger front-central N140 amplitudes in response to vibratory internal probes as compared to non-anxious controls. ERPs elicited by picture stimuli and external probes and reaction times in response to both probe types did not differ between high and low social anxiety individuals. Early somatosensory ERPs reveal an attentional bias for internal stimuli that does not appear in overt behavior. PMID:22285128

  3. [The cervical somatosensory evoked potential and its relation to F-wave activity].

    PubMed

    Strenge, H

    1989-06-01

    In 6 healthy volunteers aged 18-25 years cervical somatosensory evoked potentials (CEPs) were recorded following stimulation of the right median nerve at the wrist. At the same time the antidromically elicited individual F-waves evoked by any single impulse were recorded from the abductor pollicis brevis muscle. By means of selective averaging of the neck responses it could be shown that there was a close relationship between an F-wave-activity of 120-150 microV/stimulus or more during the trial and the appearance or the enhancement of a negative peak occurring 0.5-1.4 ms after the main CEP component N13. An F-wave-activity of more than 224 microV/stimulus regularly resulted in a total change of the CEP configuration. PMID:2503360

  4. [The significance of sex-linked differences for the assessment of somatosensory evoked potentials (author's transl)].

    PubMed

    Strenge, H; Hedderich, J; Tackmann, W

    1981-09-01

    In 45 healthy volunteers (22 males and 23 females with the same age structure) the peak latencies and inter-peak differences of the cervical and early cortical components of the somatosensory evoked potential were measured. The distribution of the values of the variables and their relationship with arm length were investigated both for the sample as a whole and for each sex separately. Significantly higher average values of the latencies and arm lengths were found in men. The correlations between arm length and latency had consistently higher values for the female sample. On the basis of these results it is concluded that a sufficient assessment of the latencies is only possible with the help of sex-specific normal values. PMID:6795015

  5. Effect of raising body temperature on visual and somatosensory evoked potentials in patients with multiple sclerosis.

    PubMed

    Matthews, W B; Read, D J; Pountney, E

    1979-03-01

    The effects of raising body temperature on the visual (VEP) and somatosensory (SEP) evoked potentials were observed in normal subjects and in patients with multiple sclerosis. The amplitude of the VEP was significantly reduced to the same degree after heating in normal subjects and in patients with multiple sclerosis but there was no effect on the latency of the potential. Changes in amplitude could not be related to reduction in acuity. In contrast, the cervical SEP was greatly disorganised after heating in many patients with multiple sclerosis while the only effect in normal subjects was to reduce the latency by increasing peripheral conduction velocity. These results suggest that heat caused conduction block in demyelinated axons in the sensory pathways of the cervical spinal cord.

  6. Dendritic branching angles of pyramidal cells across layers of the juvenile rat somatosensory cortex.

    PubMed

    Leguey, Ignacio; Bielza, Concha; Larrañaga, Pedro; Kastanauskaite, Asta; Rojo, Concepción; Benavides-Piccione, Ruth; DeFelipe, Javier

    2016-09-01

    The characterization of the structural design of cortical microcircuits is essential for understanding how they contribute to function in both health and disease. Since pyramidal neurons represent the most abundant neuronal type and their dendritic spines constitute the major postsynaptic elements of cortical excitatory synapses, our understanding of the synaptic organization of the neocortex largely depends on the available knowledge regarding the structure of pyramidal cells. Previous studies have identified several apparently common rules in dendritic geometry. We study the dendritic branching angles of pyramidal cells across layers to further shed light on the principles that determine the geometric shapes of these cells. We find that the dendritic branching angles of pyramidal cells from layers II-VI of the juvenile rat somatosensory cortex suggest common design principles, despite the particular morphological and functional features that are characteristic of pyramidal cells in each cortical layer. J. Comp. Neurol. 524:2567-2576, 2016. © 2016 Wiley Periodicals, Inc. PMID:26850576

  7. Somatosensory evoked magnetic fields arising from sources in the human cerebellum.

    PubMed

    Tesche, C D; Karhu, J

    1997-01-01

    Somatosensory evoked neuromagnetic activity of human cerebellum was recorded noninvasively with a 122-channel whole-scalp magnetometer. Cerebellar source areas activated 13-19 ms after unilateral electric stimulation of the median nerve. The first signals preceded those occurring in the primary sensorimotor cortex at around 20 ms and overlapped in time with the activation of thalamic sources. The orientation and location of most prominent cerebellar activation suggest that the detected signals represent synchronized postsynaptic activity of spinocerebellar cortex. These signals are probably elicited by the first afferent sensory volley from peripheral nerve endings and mediated by spinocerebellar (cuneocerebellar) tracts. The results imply strong coherent activation of cerebellar neuronal populations after purely sensory stimulation. Moreover, with presented methods the millisecond-scale temporal resolution of neurophysiological measurements can be more generally applied to the study of neuronal population activity in intact human cerebellum.

  8. Somatotopic source arrangement of 600 Hz oscillatory magnetic fields at the human primary somatosensory hand cortex.

    PubMed

    Curio, G; Mackert, B M; Burghoff, M; Neumann, J; Nolte, G; Scherg, M; Marx, P

    1997-10-01

    Based on low-noise superconducting quantum interference devices (SQUIDs) magnetoencephalography allows the non-invasive detection of low-amplitude high-frequency brain responses evoked about 20 ms after electric hand nerve stimulation. The main spectral energy of these brief oscillatory bursts (near 600 Hz) is in the range typical for rapidly repeated action potentials. Here, the magnetic fields of median and ulnar nerve evoked 600 Hz bursts are shown to exhibit a somatotopic arrangement at the primary somatosensory hand cortex closely resembling that of the concomitant postsynaptic primary cortical response (¿N20m'). Two possible burst generators are discussed: (1) repetitive spike volleys conducted along the terminal segments of somatotopically arranged thalamocortical axons, and (2) early intracortical spike activity in nerve-specific subterritories of the 3b hand area.

  9. Allergic contact dermatitis.

    PubMed

    Becker, Detlef

    2013-07-01

    Allergic contact dermatitis is a frequent inflammatory skin disease. The suspected diagnosis is based on clinical symptoms, a plausible contact to allergens and a suitable history of dermatitis. Differential diagnoses should be considered only after careful exclusion of any causal contact sensitization. Hence, careful diagnosis by patch testing is of great importance. Modifications of the standardized test procedure are the strip patch test and the repeated open application test. The interpretation of the SLS (sodium lauryl sulfate) patch test as well as testing with the patients' own products and working materials are potential sources of error. Accurate patch test reading is affected in particular by the experience and individual factors of the examiner. Therefore, a high degree of standardization and continuous quality control is necessary and may be supported by use of an online patch test reading course made available by the German Contact Dermatitis Research Group. A critical relevance assessment of allergic patch test reactions helps to avoid relapses and the consideration of differential diagnoses. Any allergic test reaction should be documented in an allergy ID card including the INCI name, if appropriate. The diagnostics of allergic contact dermatitis is endangered by a seriously reduced financing of patch testing by the German statutory health insurances. Restrictive regulations by the German Drug Law block the approval of new contact allergens for routine patch testing. Beside the consistent avoidance of allergen contact, temporary use of systemic and topical corticosteroids is the therapy of first choice.

  10. Computational modeling of direct neuronal recruitment during intracortical microstimulation in somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Overstreet, C. K.; Klein, J. D.; Helms Tillery, S. I.

    2013-12-01

    Objective. Electrical stimulation of cortical tissue could be used to deliver sensory information as part of a neuroprosthetic device, but current control of the location, resolution, quality, and intensity of sensations elicited by intracortical microstimulation (ICMS) remains inadequate for this purpose. One major obstacle to resolving this problem is the poor understanding of the neural activity induced by ICMS. Even with new imaging methods, quantifying the activity of many individual neurons within cortex is difficult. Approach. We used computational modeling to examine the response of somatosensory cortex to ICMS. We modeled the axonal arbors of eight distinct morphologies of interneurons and seven types of pyramidal neurons found in somatosensory cortex and identified their responses to extracellular stimulation. We then combined these axonal elements to form a multi-layered slab of simulated cortex and investigated the patterns of neural activity directly induced by ICMS. Specifically we estimated the number, location, and variety of neurons directly recruited by stimulation on a single penetrating microelectrode. Main results. The population of neurons activated by ICMS was dependent on both stimulation strength and the depth of the electrode within cortex. Strikingly, stimulation recruited interneurons and pyramidal neurons in very different patterns. Interneurons are primarily recruited within a dense, continuous region around the electrode, while pyramidal neurons were recruited in a sparse fashion both near the electrode and up to several millimeters away. Thus ICMS can lead to an unexpectedly complex spatial distribution of firing neurons. Significance. These results lend new insights to the complexity and range of neural activity that can be induced by ICMS. This work also suggests mechanisms potentially responsible for the inconsistency and unnatural quality of sensations initiated by ICMS. Understanding these mechanisms will aid in the design of

  11. Youth at risk for obesity show greater activation of striatal and somatosensory regions to food.

    PubMed

    Stice, Eric; Yokum, Sonja; Burger, Kyle S; Epstein, Leonard H; Small, Dana M

    2011-03-23

    Obese humans, compared with normal-weight humans, have less striatal D2 receptors and striatal response to food intake; weaker striatal response to food predicts weight gain for individuals at genetic risk for reduced dopamine (DA) signaling, consistent with the reward-deficit theory of obesity. Yet these may not be initial vulnerability factors, as overeating reduces D2 receptor density, D2 sensitivity, reward sensitivity, and striatal response to food. Obese humans also show greater striatal, amygdalar, orbitofrontal cortex, and somatosensory region response to food images than normal-weight humans do, which predicts weight gain for those not at genetic risk for compromised dopamine signaling, consonant with the reward-surfeit theory of obesity. However, after pairings of palatable food intake and predictive cues, DA signaling increases in response to the cues, implying that eating palatable food contributes to increased responsivity. Using fMRI, we tested whether normal-weight adolescents at high- versus low-risk for obesity showed aberrant activation of reward circuitry in response to receipt and anticipated receipt of palatable food and monetary reward. High-risk youth showed greater activation in the caudate, parietal operculum, and frontal operculum in response to food intake and in the caudate, putamen, insula, thalamus, and orbitofrontal cortex in response to monetary reward. No differences emerged in response to anticipated food or monetary reward. Data indicate that youth at risk for obesity show elevated reward circuitry responsivity in general, coupled with elevated somatosensory region responsivity to food, which may lead to overeating that produces blunted dopamine signaling and elevated responsivity to food cues.

  12. Low-level Taekwondo practitioners have better somatosensory organisation in standing balance than sedentary people.

    PubMed

    Leong, Hio-Teng; Fu, Siu N; Ng, Gabriel Y F; Tsang, William W N

    2011-08-01

    Sports training, especially for those requiring fast and skilled movements have been reported to improve one's postural control, but the underlying sensory integration mechanism is unknown. The purpose is to explore the sensory organisation strategies for maintaining standing balance in Taekwondo practitioners, and to examine the quasi-static and dynamic balance performance in subjects with and without TKD training. Case-control study was used as a study design. Eleven subjects with low level of Taekwondo training for 1-3 years, and eleven sedentary healthy subjects were assessed with the sensory organisation tests (SOT) under six visual and somatosensory input conditions and their balance upon landing from self- or operator-triggered drop test with the eyes closed condition. The SOT measured the equilibrium scores, whereas the drop test assessed the time to stabilisation (TTS), normalised peak force and distance of antero-posterior and medial-lateral centre of pressure on landing. Results for the SOT test revealed that Taekwondo subjects performed better during stance with eyes closed on a fixed support than the untrained group (p = 0.011). For the drop tests, the untrained group was slower in postural correction as revealed by the longer TTS than the Taekwondo group after the operator-triggered drops (p = 0.018). All subjects had a larger normalised peak force in operator-triggered than self-triggered drops. In conclusion, we observed that people with low-level Taekwondo training have better balance performance than untrained subjects as shown in the SOT results and shorter TTS with the drop test. They may rely more on the somatosensory and vestibular inputs for maintaining balance. People with balance problems may benefit from Taekwondo training.

  13. Enhanced Somatosensory Feedback Reduces Prefrontal Cortical Activity During Walking in Older Adults

    PubMed Central

    Christou, Evangelos A.; Ring, Sarah A.; Williamson, John B.; Doty, Leilani

    2014-01-01

    Background. The coordination of steady state walking is relatively automatic in healthy humans, such that active attention to the details of task execution and performance (controlled processing) is low. Somatosensation is a crucial input to the spinal and brainstem circuits that facilitate this automaticity. Impaired somatosensation in older adults may reduce automaticity and increase controlled processing, thereby contributing to deficits in walking function. The primary objective of this study was to determine if enhancing somatosensory feedback can reduce controlled processing during walking, as assessed by prefrontal cortical activation. Methods. Fourteen older adults (age 77.1±5.56 years) with mild mobility deficits and mild somatosensory deficits participated in this study. Functional near-infrared spectroscopy was used to quantify metabolic activity (tissue oxygenation index, TOI) in the prefrontal cortex. Prefrontal activity and gait spatiotemporal data were measured during treadmill walking and overground walking while participants wore normal shoes and under two conditions of enhanced somatosensation: wearing textured insoles and no shoes. Results. Relative to walking with normal shoes, textured insoles yielded a bilateral reduction of prefrontal cortical activity for treadmill walking (ΔTOI = −0.85 and −1.19 for left and right hemispheres, respectively) and for overground walking (ΔTOI = −0.51 and −0.66 for left and right hemispheres, respectively). Relative to walking with normal shoes, no shoes yielded lower prefrontal cortical activity for treadmill walking (ΔTOI = −0.69 and −1.13 for left and right hemispheres, respectively), but not overground walking. Conclusions. Enhanced somatosensation reduces prefrontal activity during walking in older adults. This suggests a less intensive utilization of controlled processing during walking. PMID:25112494

  14. Heightened sensitivity to somatosensory stimuli in anorexia nervosa: an exploratory study with the SASTCA scale.

    PubMed

    Calvo Sagardoy, Rosa; Gallego Morales, Luis T; Kassem García, Soledad; Codesal Julián, Rosana; Blanco Fernández, Ascensión; Solórzano Ostolaza, Gloria; Morales Martínez, Carmen

    2014-11-04

    Objetivo: destacar la presencia de una sensibilidad extrema hacia estímulos externos e internos (Amplificación Somatosensorial) en pacientes con Anorexia, similar pero no idéntica, a la descrita en pacientes con unexple somatic symtoms. Método: Se ha elaborado una escala de Amplificación Somatosensorial para Trastornos de la Conducta Alimentaria, (SASTCA), que mide la intensidad de la respuesta hacia estímulos somatosensoriales específicos. La escala ha sido cumplimentada por un grupo de 48 pacientes anoréxicas y un grupo control de 31 sujetos emparejados en edad, sexo y nivel socioeducativo. Los resultados se han comparado con los obtenidos en la escala SSAS de Barsky. Resultados: La Fiabilidad (Alfa de Cronbach 0,946; dos mitades de Guttman 0,936) y la Validez (ROC, 0,933), son indicativas de elevada sensibilidad y especificidad de la escala SASTCA. El grupo de pacientes presenta una media 58,73 12,38, significativamente superior al grupo control 37,81 7,47, (=0,001). Las pacientes presentan en la escala SSAS una media 31,21 6,68 significativamente superior al grupo control 26,58 5,49 (=0,01), aunque la diferencia es menos extremada. Ambas escalas correlacionan positivamente. 0,634 Conclusiones: Los resultados sugieren la presencia en AN. de una sensibilidad extrema hacia estímulos somatosensoriales. ¿Podria esta elevada sensibilidad sensorial ayudarnos a explicar el proceso de formación del auto-concepto distorsionado (“gordo, enfermo, feo”) de estos pacientes? De confirmar su presencia en otras muestras de pacientes con anorexia, en sus familiares y en diferentes pacientes somatomorfos o TCA, esta elevada sensibilidad podría considerarse el endofenotipo somatomorfo del trastorno anoréxico.

  15. Youth at Risk for Obesity Show Greater Activation of Striatal and Somatosensory Regions to Food

    PubMed Central

    Stice, E; Yokum, S; Burger, KS; Epstein, LH; Small, DM

    2011-01-01

    Obese versus normal-weight humans have less striatal D2 receptors and striatal response to food intake, and weaker striatal response to food predicts weight gain for individuals at genetic risk for reduced dopamine (DA) signaling, consistent with the reward deficit theory of obesity. Yet these may not be initial vulnerability factors, as overeating reduces D2 receptor density, D2 sensitivity, reward sensitivity, and striatal response to food. Obese versus normal-weight humans also show greater striatal, amygdalar, orbitofrontal cortex, and somatosensory region response to food images, which predicts weight gain for those not at genetic risk for compromised dopamine signaling, consonant with the reward surfeit theory of obesity. However, after pairings of palatable food intake and predictive cues, DA signaling increases in response to the cues, implying that eating palatable food contributes to increased responsivity. We tested whether normal-weight adolescents at high- versus low-risk for obesity showed aberrant activation of reward circuitry in response to receipt and anticipated receipt of palatable food and monetary reward using fMRI. High-risk youth showed greater activation in the caudate, parietal operculum, and frontal operculum in response to food intake and in the caudate, putamen, insula, thalamus, and orbitofrontal cortex in response to monetary reward. No differences emerged in response to anticipated food or monetary reward. Data indicate that youth at risk for obesity show elevated reward circuitry responsivity in general coupled with elevated somatosensory region responsivity to food, which may lead to overeating that produces blunted dopamine signaling and elevated responsivity to food cues. PMID:21430137

  16. Youth at risk for obesity show greater activation of striatal and somatosensory regions to food.

    PubMed

    Stice, Eric; Yokum, Sonja; Burger, Kyle S; Epstein, Leonard H; Small, Dana M

    2011-03-23

    Obese humans, compared with normal-weight humans, have less striatal D2 receptors and striatal response to food intake; weaker striatal response to food predicts weight gain for individuals at genetic risk for reduced dopamine (DA) signaling, consistent with the reward-deficit theory of obesity. Yet these may not be initial vulnerability factors, as overeating reduces D2 receptor density, D2 sensitivity, reward sensitivity, and striatal response to food. Obese humans also show greater striatal, amygdalar, orbitofrontal cortex, and somatosensory region response to food images than normal-weight humans do, which predicts weight gain for those not at genetic risk for compromised dopamine signaling, consonant with the reward-surfeit theory of obesity. However, after pairings of palatable food intake and predictive cues, DA signaling increases in response to the cues, implying that eating palatable food contributes to increased responsivity. Using fMRI, we tested whether normal-weight adolescents at high- versus low-risk for obesity showed aberrant activation of reward circuitry in response to receipt and anticipated receipt of palatable food and monetary reward. High-risk youth showed greater activation in the caudate, parietal operculum, and frontal operculum in response to food intake and in the caudate, putamen, insula, thalamus, and orbitofrontal cortex in response to monetary reward. No differences emerged in response to anticipated food or monetary reward. Data indicate that youth at risk for obesity show elevated reward circuitry responsivity in general, coupled with elevated somatosensory region responsivity to food, which may lead to overeating that produces blunted dopamine signaling and elevated responsivity to food cues. PMID:21430137

  17. Hmx1 is required for the normal development of somatosensory neurons in the geniculate ganglion.

    PubMed

    Quina, Lely A; Tempest, Lynne; Hsu, Yun-Wei A; Cox, Timothy C; Turner, Eric E

    2012-05-01

    Hmx1 is a variant homeodomain transcription factor expressed in the developing sensory nervous system, retina, and craniofacial mesenchyme. Recently, mutations at the Hmx1 locus have been linked to craniofacial defects in humans, rats, and mice, but its role in nervous system development is largely unknown. Here we show that Hmx1 is expressed in a subset of sensory neurons in the cranial and dorsal root ganglia which does not correspond to any specific sensory modality. Sensory neurons in the dorsal root and trigeminal ganglia of Hmx1dm/dm mouse embryos have no detectable Hmx1 protein, yet they undergo neurogenesis and express sensory subtype markers normally, demonstrating that Hmx1 is not globally required for the specification of sensory neurons from neural crest precursors. Loss of Hmx1 expression has no obvious effect on the early development of the trigeminal (V), superior (IX/X), or dorsal root ganglia neurons in which it is expressed, but results in marked defects in the geniculate (VII) ganglion. Hmx1dm/dm mouse embryos possess only a vestigial posterior auricular nerve, and general somatosensory neurons in the geniculate ganglion are greatly reduced by mid-gestation. Although Hmx1 is expressed in geniculate neurons prior to cell cycle exit, it does not appear to be required for neurogenesis, and the loss of geniculate neurons is likely to be the result of increased cell death. Fate mapping of neural crest-derived tissues indicates that Hmx1-expressing somatosensory neurons at different axial levels may be derived from either the neural crest or the neurogenic placodes. PMID:22586713

  18. Observing another in pain facilitates vicarious experiences and modulates somatosensory experiences

    PubMed Central

    Vandenbroucke, Sophie; Crombez, Geert; Loeys, Tom; Goubert, Liesbet

    2014-01-01

    Objective: This study investigated whether individuals reporting vicarious pain in daily life (e.g., the self-reported vicarious pain group) display vicarious experiences during an experimental paradigm, and also show an improved detection of somatosensory stimuli while observing another in pain. Furthermore, this study investigated the stability of these phenomena. Finally, this study explored the putative modulating role of dispositional empathy and hypervigilance for pain. Methods: Vicarious pain responders (i.e., reporting vicarious pain in daily life; N = 16) and controls (N = 19) were selected from a large sample, and viewed videos depicting pain-related (hands being pricked) and non-pain related scenes, whilst occasionally experiencing vibrotactile stimuli themselves on the left, right or both hands. Participants reported the location at which they felt a somatosensory stimulus. We calculated the number of vicarious errors (i.e., the number of trials in which an illusionary sensation was reported while observing pain-related scenes) and detection accuracy. Thirty-three participants (94.29%) took part in the same experiment 5 months later to investigate the temporal stability of the outcomes. Results: The vicarious pain group reported more vicarious errors compared with controls and this effect proved to be stable over time. Detection was facilitated while observing pain-related scenes compared with non-pain related scenes. Observers' characteristics, i.e., dispositional empathy and hypervigilance for pain, did not modulate the effects. Conclusion: Observing pain facilitates the detection of tactile stimuli, both in vicarious pain responders and controls. Interestingly, vicarious pain responders reported more vicarious errors during the experimental paradigm compared to controls and this effect remained stable over time. PMID:25191251

  19. Limb-state information encoded by peripheral and central somatosensory neurons: Implications for an afferent interface

    PubMed Central

    Weber, Douglas J.; London, Brian M.; Hokanson, James A.; Ayers, Christopher A.; Gaunt, Robert A.; Torres, Ricardo R.; Zaaimi, Boubker; Miller, Lee E.

    2013-01-01

    A major issue to be addressed in the development of neural interfaces for prosthetic control is the need for somatosensory feedback. Here, we investigate two possible strategies: electrical stimulation of either dorsal root ganglia (DRG) or primary somatosensory cortex (S1). In each approach, we must determine a model that reflects the representation of limb state in terms of neural discharge. This model can then be used to design stimuli that artificially activate the nervous system to convey information about limb state to the subject. Electrically activating DRG neurons using naturalistic stimulus patterns, modeled on recordings made during passive limb movement, evoked activity in S1 that was similar to that of the original movement. We also found that S1 neural populations could accurately discriminate different patterns of DRG stimulation across a wide range of stimulus pulse-rates. In studying the neural coding of limb-state in S1, we also decoded the kinematics of active limb movement using multi-electrode recordings in the monkey. Neurons having both proprioceptive and cutaneous receptive fields contributed equally to this decoding. Some neurons were most informative of limb state in the recent past, but many others appeared to signal upcoming movements suggesting that they also were modulated by an efference copy signal. Finally, we show that a monkey was able to detect stimulation through a large percentage of electrodes implanted in area 2. We discuss the design of appropriate stimulus paradigms for conveying time-varying limb state information, and the relative merits and limitations of central and peripheral approaches. PMID:21878419

  20. BOLD fMRI of visual and somatosensory-motor stimulations in baboons.

    PubMed

    Wey, Hsiao-Ying; Li, Jinqi; Szabó, C Akos; Fox, Peter T; Leland, M Michelle; Jones, Lisa; Duong, Timothy Q

    2010-10-01

    Baboon, with its large brain size and extensive cortical folding compared to other non-human primates, serves as a good model for neuroscience research. This study reports the implementation of a baboon model for blood oxygenation level-dependent (BOLD) fMRI studies (1.5 x 1.5 x 4 mm resolution) on a clinical 3T-MRI scanner. BOLD fMRI responses to hypercapnic (5% CO(2)) challenge, 10 Hz flicker visual, and vibrotactile somatosensory-motor stimulations were investigated in baboons anesthetized sequentially with isoflurane and ketamine. Hypercapnia evoked robust BOLD increases. Paralysis was determined to be necessary to achieve reproducible functional activations within and between subjects under our experimental conditions. With optimized anesthetic doses (0.8-1.0% isoflurane or 6-8 mg/kg/h ketamine) and adequate paralysis (vecuronium, 0.2 mg/kg), robust activations were detected in the visual (V), primary (S1) and secondary (S2) somatosensory, primary motor (M cortices), supplementary motor area (SMA), lateral geniculate nucleus (LGN) and thalamus (Th). Data were tabulated for 11 trials under isoflurane and 10 trials under ketamine on 5 baboons. S1, S2, M, and V activations were detected in essentially all trials (90-100% of the time, except 82% for S2 under isoflurane and 70% for M under ketamine). LGN activations were detected 64-70% of the time under both anesthetics. SMA and Th activations were detected 36-45% of the time under isoflurane and 60% of the time under ketamine. BOLD percent changes among different structures were slightly higher under ketamine than isoflurane (0.75% versus 0.58% averaging all structures), but none was statistically different (P>0.05). This baboon model offers an opportunity to non-invasively image brain functions and dysfunctions in large non-human primates.

  1. Endocannabinoid modulation of hyperaemia evoked by physiologically relevant stimuli in the rat primary somatosensory cortex

    PubMed Central

    Ho, W-SV; Patel, S; Thompson, JR; Roberts, CJ; Stuhr, KL; Hillard, CJ

    2010-01-01

    Background and purpose: In vitro studies demonstrate that cannabinoid CB1 receptors subserve activity-dependent suppression of inhibition in the neocortex. To examine this mechanism in vivo, we assessed the effects of local changes in CB1 receptor activity on somatosensory cortex neuronal activation by whisker movement in rats. Experimental approach: Laser Doppler flowmetry and c-Fos immunohistochemistry were used to measure changes in local blood flow and neuronal activation, respectively. All drugs were applied directly to the cranium above the whisker barrel fields of the primary somatosensory cortex. Key results: The CB1 receptor agonist WIN55212-2 potentiated the hyperaemia induced by whisker movement and this potentiation was occluded by bicuculline. The CB1 receptor antagonists, rimonabant and AM251, inhibited hyperaemic responses to whisker movement; indicating that activation of endogenous CB1 receptors increased during whisker movement. Whisker movement-induced expression of c-Fos protein in neurons of the whisker barrel cortex was inhibited by rimonabant. Movement of the whiskers increased the 2-arachidonoylglycerol content in the contralateral, compared to the ipsilateral, sensory cortex. Conclusions and implications: These results support the hypothesis that endocannabinoid signalling is recruited during physiologically relevant activation of the sensory cortex. These data support the hypothesis that the primary effect of CB1 receptor activation within the activated whisker barrel cortex is to inhibit GABA release, resulting in disinhibition of neuronal activation. These studies provide physiological data involving endocannabinoid signalling in activity-dependent regulation of neuronal activation and provide a mechanistic basis for the effects of cannabis use on sensory processing in humans. This article is part of a themed issue on Cannabinoids. To view the editorial for this themed issue visit http://dx.doi.org/10.1111/j.1476-5381.2010.00831.x PMID

  2. Muscle- and Skin-Derived Cues Jointly Orchestrate Patterning of Somatosensory Dendrites.

    PubMed

    Díaz-Balzac, Carlos A; Rahman, Maisha; Lázaro-Peña, María I; Martin Hernandez, Lourdes A; Salzberg, Yehuda; Aguirre-Chen, Cristina; Kaprielian, Zaven; Bülow, Hannes E

    2016-09-12

    Sensory dendrite arbors are patterned through cell-autonomously and non-cell-autonomously functioning factors [1-3]. Yet, only a few non-cell-autonomously acting proteins have been identified, including semaphorins [4, 5], brain-derived neurotrophic factors (BDNFs) [6], UNC-6/Netrin [7], and the conserved MNR-1/Menorin-SAX-7/L1CAM cell adhesion complex [8, 9]. This complex acts from the skin to pattern the stereotypic dendritic arbors of PVD and FLP somatosensory neurons in Caenorhabditis elegans through the leucine-rich transmembrane receptor DMA-1/LRR-TM expressed on PVD neurons [8, 9]. Here we describe a role for the diffusible C. elegans protein LECT-2, which is homologous to vertebrate leukocyte cell-derived chemotaxin 2 (LECT2)/Chondromodulin II. LECT2/Chondromodulin II has been implicated in a variety of pathological conditions [10-13], but the developmental functions of LECT2 have remained elusive. We find that LECT-2/Chondromodulin II is required for development of PVD and FLP dendritic arbors and can act as a diffusible cue from a distance to shape dendritic arbors. Expressed in body-wall muscles, LECT-2 decorates neuronal processes and hypodermal cells in a pattern similar to the cell adhesion molecule SAX-7/L1CAM. LECT-2 functions genetically downstream of the MNR-1/Menorin-SAX-7/L1CAM adhesion complex and upstream of the DMA-1 receptor. LECT-2 localization is dependent on SAX-7/L1CAM, but not on MNR-1/Menorin or DMA-1/LRR-TM, suggesting that LECT-2 functions as part of the skin-derived MNR-1/Menorin-SAX-7/L1CAM adhesion complex. Collectively, our findings suggest that LECT-2/Chondromodulin II acts as a muscle-derived, diffusible cofactor together with a skin-derived cell adhesion complex to orchestrate the molecular interactions of three tissues during patterning of somatosensory dendrites. PMID:27451901

  3. Congenital foot deformation alters the topographic organization in the primate somatosensory system.

    PubMed

    Liao, Chia-Chi; Qi, Hui-Xin; Reed, Jamie L; Miller, Daniel J; Kaas, Jon H

    2016-01-01

    Limbs may fail to grow properly during fetal development, but the extent to which such growth alters the nervous system has not been extensively explored. Here we describe the organization of the somatosensory system in a 6-year-old monkey (Macaca radiata) born with a deformed left foot in comparison to the results from a normal monkey (Macaca fascicularis). Toes 1, 3, and 5 were missing, but the proximal parts of toes 2 and 4 were present. We used anatomical tracers to characterize the patterns of peripheral input to the spinal cord and brainstem, as well as between thalamus and cortex. We also determined the somatotopic organization of primary somatosensory area 3b of both hemispheres using multiunit electrophysiological recording. Tracers were subcutaneously injected into matching locations of each foot to reveal their representations within the lumbar spinal cord, and the gracile nucleus (GrN) of the brainstem. Tracers injected into the representations of the toes and plantar pads of cortical area 3b labeled neurons in the ventroposterior lateral nucleus (VPL) of the thalamus. Contrary to the orderly arrangement of the foot representation throughout the lemniscal pathway in the normal monkey, the plantar representation of the deformed foot was significantly expanded and intruded into the expected representations of toes in the spinal cord, GrN, VPL, and area 3b. We also observed abnormal representation of the intact foot in the ipsilateral spinal cord and contralateral area 3b. Thus, congenital malformation influences the somatotopic representation of the deformed as well as the intact foot.

  4. Learned control over spinal nociception reduces supraspinal nociception as quantified by late somatosensory evoked potentials.

    PubMed

    Ruscheweyh, Ruth; Bäumler, Maximilian; Feller, Moritz; Krafft, Stefanie; Sommer, Jens; Straube, Andreas

    2015-12-01

    We have recently shown that subjects can learn to use cognitive-emotional strategies to suppress their spinal nociceptive flexor reflex (RIII reflex) under visual RIII feedback and proposed that this reflects learned activation of descending pain inhibition. Here, we investigated whether learned RIII suppression also affects supraspinal nociception and whether previous relaxation training increases success. Subjects were trained over 3 sessions to reduce their RIII size by self-selected cognitive-emotional strategies. Two groups received true RIII feedback (with or without previous relaxation training) and a sham group received false feedback (15 subjects per group). RIII reflexes, late somatosensory evoked potentials (SEPs), and F-waves were recorded and pain intensity ratings collected. Both true feedback groups achieved significant (P < 0.01) but similar RIII suppression (to 79% ± 21% and 70% ± 17% of control). Somatosensory evoked potential amplitude (100-150 milliseconds after stimulation) was reduced in parallel with the RIII size (r = 0.57, P < 0.01). In the sham group, neither RIII size nor SEP amplitude was significantly reduced during feedback training. Pain intensity was significantly reduced in all 3 groups and also correlated with RIII reduction (r = 0.44, P < 0.01). F-wave parameters were not affected during RIII suppression. The present results show that learned RIII suppression also affects supraspinal nociception as quantified by SEPs, although effects on pain ratings were less clear. Lower motor neuron excitability as quantified by F-waves was not affected. Previous relaxation training did not significantly improve RIII feedback training success. PMID:26270584

  5. Giant early components of somatosensory evoked potentials to tibial nerve stimulation in cortical myoclonus.

    PubMed

    Anzellotti, Francesca; Onofrj, Marco; Bonanni, Laura; Saracino, Antonio; Franciotti, Raffaella

    2016-01-01

    Enlarged cortical components of somatosensory evoked potentials (giant SEPs) recorded by electroencephalography (EEG) and abnormal somatosensory evoked magnetic fields (SEFs) recorded by magnetoencephalography (MEG) are observed in the majority of patients with cortical myoclonus (CM). Studies on simultaneous recordings of SEPs and SEFs showed that generator mechanism of giant SEPs involves both primary sensory and motor cortices. However the generator sources of giant SEPs have not been fully understood as only one report describes clearly giant SEPs following lower limb stimulation. In our study we performed a combined EEG-MEG recording on responses elicited by electric median and tibial nerve stimulation in a patient who developed consequently to methyl bromide intoxication CM with giant SEPs to median and tibial nerve stimuli. SEPs wave shapes were identified on the basis of polarity-latency components (e.g. P15-N20-P25) as defined by earlier studies and guidelines. At EEG recording, the SEP giant component did not appear in the latency range of the first cortical component for median nerve SEP (N20), but appeared instead in the range of the P37 tibial nerve SEP, which is currently identified as the first cortical component elicited by tibial nerve stimuli. Our MEG and EEG SEPs recordings also showed that components in the latency range of P37 were preceded by other cortical components. These findings suggest that lower limb P37 does not correspond to upper limb N20. MEG results confirmed that giant SEFs are the second component from both tibial (N43m-P43m) and median (N27m-P27m) nerve stimulation. MEG dipolar sources of these giant components were located in the primary sensory and motor area. PMID:27489768

  6. Tactile response adaptation to whisker stimulation in the lemniscal somatosensory pathway of rats.

    PubMed

    Martin-Cortecero, Jesus; Nuñez, Angel

    2014-12-01

    Response adaptation is associated with attenuation of neural responses as the result of different mechanisms. However, the main function of adaptation may be to enhance the flow of relevant information transmission in sensory pathways. To study tactile response adaptation in the somatosensory pathway, unit recordings were performed in the principal trigeminal nucleus, ventro postero-medial thalamic nucleus and barrel cortex by means of tungsten microelectrodes in urethane anesthetized rats. Tactile stimuli consisted in 20 ms duration whisker deflections at different frequencies (0.5-10 Hz). Presumably pyramidal cortical neurons showed response adaptation at frequencies >2 Hz while putative inhibitory cortical neurons did not show response adaptation at 0.5, 5 or 10 Hz. Inhibitory activity was increased by muscimol application into the cortex (8mM, 0.1 µl); in this condition cortical adaptation was not affected, suggesting that adaptation was not due to an increase of inhibitory mechanisms. Adaptation was also observed in subcortical structures although the response attenuation was lesser than in the barrel cortex. Adaptation remained in subcortical structures after reversible cortical inactivation by cooling the barrel cortex. Acetylcholine application (10 μM; 0.1 μl) into the barrel cortex reduced response adaptation through the activation of muscarinic receptors because the effect was blocked by intraperitoneal injection of atropine (1mg/kg), suggesting that adaptation may change according to the cortical Ach level. Results indicate that response adaptation increases along the somatosensory pathway probably to alter the sensitivity of neurons in order to encode sensory stimuli more efficiently and to enhance the detectability of rare stimuli.

  7. Telescopic vision contact lens

    NASA Astrophysics Data System (ADS)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  8. Optical contacting of quartz

    NASA Technical Reports Server (NTRS)

    Payne, L. L.

    1982-01-01

    The strength of the bond between optically contacted quartz surfaces was investigated. The Gravity Probe-B (GP-B) experiment to test the theories of general relativity requires extremely precise measurements. The quartz components of the instruments to make these measurements must be held together in a very stable unit. Optical contacting is suggested as a possible method of joining these components. The fundamental forces involved in optical contacting are reviewed and relates calculations of these forces to the results obtained in experiments.

  9. Contact microscopy with synchrotron radiation

    SciTech Connect

    Panessa-Warren, B.J.

    1985-10-01

    Soft x-ray contact microscopy with synchrotron radiation offers the biologist and especially the microscopist, a way to morphologically study specimens that could not be imaged by conventional TEM, STEM or SEM methods (i.e. hydrated samples, samples easily damaged by an electron beam, electron dense samples, thick specimens, unstained low contrast specimens) at spatial resolutions approaching those of the TEM, with the additional possibility to obtain compositional (elemental) information about the sample as well. Although flash x-ray sources offer faster exposure times, synchrotron radiation provides a highly collimated, intense radiation that can be tuned to select specific discrete ranges of x-ray wavelengths or specific individual wavelengths which optimize imaging or microanalysis of a specific sample. This paper presents an overview of the applications of x-ray contact microscopy to biological research and some current research results using monochromatic synchrotron radiation to image biological samples. 24 refs., 10 figs.

  10. Occupational Contact Dermatitis

    PubMed Central

    2008-01-01

    Occupational contact dermatitis accounts for 90% of all cases of work-related cutaneous disorders. It can be divided into irritant contact dermatitis, which occurs in 80% of cases, and allergic contact dermatitis. In most cases, both types will present as eczematous lesions on exposed parts of the body, notably the hands. Accurate diagnosis relies on meticulous history taking, thorough physical examination, careful reading of Material Safety Data Sheets to distinguish between irritants and allergens, and comprehensive patch testing to confirm or rule out allergic sensitization. This article reviews the pathogenesis and clinical manifestations of occupational contact dermatitis and provides diagnostic guidelines and a rational approach to management of these often frustrating cases. PMID:20525126

  11. Contacting American Overseas Schools.

    ERIC Educational Resources Information Center

    Engelhardt, David

    1993-01-01

    Provides contacts for architects or educational consultants who wish to work overseas. Cites a directory, newsletters, newspapers, and associations focused on educators involved with independent overseas schools that are organized around the United States curriculum. (MLF)

  12. Relay contact monitoring system

    SciTech Connect

    Mehta, V.

    1994-01-11

    A switching system for switching on and off heating and air conditioning units in an environmental control system. The switching system includes a thermostat and a relay conductively coupled to the thermostat. The relay has a contact, which is responsive to a change signal for changing its position. The system further includes a programmable monitor having predetermined positions stored in a memory. The monitor is conductively coupled to the contact and to the thermostat for continually determining the position of the contact, and for sending a change signal to the relay for switching the position of the contact, as needed, to be in conformance with a predetermined position stored in the memory. 3 figs.

  13. Contact gating at GHz frequency in graphene

    PubMed Central

    Wilmart, Q.; Inhofer, A.; Boukhicha, M.; Yang, W.; Rosticher, M.; Morfin, P.; Garroum, N.; Fève, G.; Berroir, J.-M.; Plaçais, B.

    2016-01-01

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates. PMID:26879709

  14. Contact gating at GHz frequency in graphene

    NASA Astrophysics Data System (ADS)

    Wilmart, Q.; Inhofer, A.; Boukhicha, M.; Yang, W.; Rosticher, M.; Morfin, P.; Garroum, N.; Fève, G.; Berroir, J.-M.; Plaçais, B.

    2016-02-01

    The paradigm of graphene transistors is based on the gate modulation of the channel carrier density by means of a local channel gate. This standard architecture is subject to the scaling limit of the channel length and further restrictions due to access and contact resistances impeding the device performance. We propose a novel design, overcoming these issues by implementing additional local gates underneath the contact region which allow a full control of the Klein barrier taking place at the contact edge. In particular, our work demonstrates the GHz operation of transistors driven by independent contact gates. We benchmark the standard channel and novel contact gating and report for the later dynamical transconductance levels at the state of the art. Our finding may find applications in electronics and optoelectronics whenever there is need to control independently the Fermi level and the electrostatic potential of electronic sources or to get rid of cumbersome local channel gates.

  15. The impact of contact

    NASA Astrophysics Data System (ADS)

    Finney, B.

    1986-10-01

    Scenarios of the impact on human society of radio contact with an extraterrestrial civilization are presented. Some believe that contact with advanced extraterrestrials would quickly devastate the human spirit, while others believe that these super-intelligent beings would show the inhabitants of the earth how to live in peace. It is proposed that the possible existence of extraterrestrial civilizations and the development of means of studying and communicating with them need to be considered.

  16. ELECTRIC CONTACT MEANS

    DOEpatents

    Grear, J.W. Jr.

    1959-03-10

    A switch adapted to maintain electrical connections under conditions of vibration or acceleration is described. According to the invention, thc switch includes a rotatable arm carrying a conductive bar arranged to close against two contacts spaced in the same plane. The firm and continuous engagement of the conductive bar with the contacts is acheived by utilizeing a spring located betwenn the vbar and athe a rem frzme and slidable mounting the bar in channel between two arms suspendef from the arm frame.

  17. Lettuce contact allergy.

    PubMed

    Paulsen, Evy; Andersen, Klaus E

    2016-02-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy.

  18. Additive Manufacturing Infrared Inspection

    NASA Technical Reports Server (NTRS)

    Gaddy, Darrell

    2014-01-01

    Additive manufacturing is a rapid prototyping technology that allows parts to be built in a series of thin layers from plastic, ceramics, and metallics. Metallic additive manufacturing is an emerging form of rapid prototyping that allows complex structures to be built using various metallic powders. Significant time and cost savings have also been observed using the metallic additive manufacturing compared with traditional techniques. Development of the metallic additive manufacturing technology has advanced significantly over the last decade, although many of the techniques to inspect parts made from these processes have not advanced significantly or have limitations. Several external geometry inspection techniques exist such as Coordinate Measurement Machines (CMM), Laser Scanners, Structured Light Scanning Systems, or even traditional calipers and gages. All of the aforementioned techniques are limited to external geometry and contours or must use a contact probe to inspect limited internal dimensions. This presentation will document the development of a process for real-time dimensional inspection technique and digital quality record of the additive manufacturing process using Infrared camera imaging and processing techniques.

  19. Surrogate Modeling of Deformable Joint Contact using Artificial Neural Networks

    PubMed Central

    Eskinazi, Ilan; Fregly, Benjamin J.

    2016-01-01

    Deformable joint contact models can be used to estimate loading conditions for cartilage-cartilage, implant-implant, human-orthotic, and foot-ground interactions. However, contact evaluations are often so expensive computationally that they can be prohibitive for simulations or optimizations requiring thousands or even millions of contact evaluations. To overcome this limitation, we developed a novel surrogate contact modeling method based on artificial neural networks (ANNs). The method uses special sampling techniques to gather input-output data points from an original (slow) contact model in multiple domains of input space, where each domain represents a different physical situation likely to be encountered. For each contact force and torque output by the original contact model, a multi-layer feed-forward ANN is defined, trained, and incorporated into a surrogate contact model. As an evaluation problem, we created an ANN-based surrogate contact model of an artificial tibiofemoral joint using over 75,000 evaluations of a fine-grid elastic foundation (EF) contact model. The surrogate contact model computed contact forces and torques about 1000 times faster than a less accurate coarse grid EF contact model. Furthermore, the surrogate contact model was seven times more accurate than the coarse grid EF contact model within the input domain of a walking motion. For larger input domains, the surrogate contact model showed the expected trend of increasing error with increasing domain size. In addition, the surrogate contact model was able to identify out-of-contact situations with high accuracy. Computational contact models created using our proposed ANN approach may remove an important computational bottleneck from musculoskeletal simulations or optimizations incorporating deformable joint contact models. PMID:26220591

  20. The contribution of primary and secondary somatosensory cortices to the representation of body parts and body sides: an fMRI adaptation study.

    PubMed

    Tamè, Luigi; Braun, Christoph; Lingnau, Angelika; Schwarzbach, Jens; Demarchi, Gianpaolo; Li Hegner, Yiwen; Farnè, Alessandro; Pavani, Francesco

    2012-12-01

    Although the somatosensory homunculus is a classically used description of the way somatosensory inputs are processed in the brain, the actual contributions of primary (SI) and secondary (SII) somatosensory cortices to the spatial coding of touch remain poorly understood. We studied adaptation of the fMRI BOLD response in the somatosensory cortex by delivering pairs of vibrotactile stimuli to the finger tips of the index and middle fingers. The first stimulus (adaptor) was delivered either to the index or to the middle finger of the right or left hand, and the second stimulus (test) was always administered to the left index finger. The overall BOLD response evoked by the stimulation was primarily contralateral in SI and was more bilateral in SII. However, our fMRI adaptation approach also revealed that both somatosensory cortices were sensitive to ipsilateral as well as to contralateral inputs. SI and SII adapted more after subsequent stimulation of homologous as compared with nonhomologous fingers, showing a distinction between different fingers. Most importantly, for both somatosensory cortices, this finger-specific adaptation occurred irrespective of whether the tactile stimulus was delivered to the same or to different hands. This result implies integration of contralateral and ipsilateral somatosensory inputs in SI as well as in SII. Our findings suggest that SI is more than a simple relay for sensory information and that both SI and SII contribute to the spatial coding of touch by discriminating between body parts (fingers) and by integrating the somatosensory input from the two sides of the body (hands).

  1. Common contact sensitizers in Delhi.

    PubMed

    Singhal, V; Reddy, B S

    2000-07-01

    Seventy-five patients of both sexes with clinically suspected contact dermatitis were patch tested with the Indian Standard Series and indigenous antigens. The results were compared with the data from other centers. Most of these patients were young adults between 20 and 39 yrs old with the mean age of 36.63 +/- 5.6 yrs. Their occupational profiles included household workers (17.33%), masons (10.66%), farmers (6.66%), factory workers (4%), medical personnel (4%), lab workers (2.66%), and miscellaneous (17.33%). Itching and burning were two of the most common complaints, and chronic dermatitis was the predominant morphologic pattern of the lesions observed. Frequent sites involved included the hands (40.83%), airborne type (22.44%), hands and feet (12.24%), feet (12.24%), face (10.2%), and neck (2.04%). Patch test analysis of these patients revealed that, out of 75 subjects tested, 49 (65.3%) reacted to one or more allergens. Parthenium (20%) is the most common contact sensitizer followed by potassium dichromate (16%), xanthium (13.33%), nickel sulphate (12%), chrysanthemum (8%), mercaptobenzothiazole, and garlic (6.66% each). These findings are in broad conformity with those in other reports. We concluded that the Indian Standard Series of antigens with the addition of a few more (such as garlic, onion and chlorheximide of local relevance) is suitable for detecting the allergens responsible for the contact dermatitis prevailing in this region. PMID:10935340

  2. The contact caveat: negative contact predicts increased prejudice more than positive contact predicts reduced prejudice.

    PubMed

    Barlow, Fiona Kate; Paolini, Stefania; Pedersen, Anne; Hornsey, Matthew J; Radke, Helena R M; Harwood, Jake; Rubin, Mark; Sibley, Chris G

    2012-12-01

    Contact researchers have largely overlooked the potential for negative intergroup contact to increase prejudice. In Study 1, we tested the interaction between contact quantity and valence on prejudice toward Black Australians (n = 1,476), Muslim Australians (n = 173), and asylum seekers (n = 293). In all cases, the association between contact quantity and prejudice was moderated by its valence, with negative contact emerging as a stronger and more consistent predictor than positive contact. In Study 2, White Americans (n = 441) indicated how much positive and negative contact they had with Black Americans on separate measures. Although both quantity of positive and negative contact predicted racism and avoidance, negative contact was the stronger predictor. Furthermore, negative (but not positive) contact independently predicted suspicion about Barack Obama's birthplace. These results extend the contact hypothesis by issuing an important caveat: Negative contact may be more strongly associated with increased racism and discrimination than positive contact is with its reduction.

  3. Contact Lenses for Vision Correction

    MedlinePlus

    ... Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd Reviewed by: Brenda ... on the surface of the eye. They correct vision like eyeglasses do and are safe when used ...

  4. Shoe allergic contact dermatitis.

    PubMed

    Matthys, Erin; Zahir, Amir; Ehrlich, Alison

    2014-01-01

    Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years.

  5. Acrylate Systemic Contact Dermatitis.

    PubMed

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates.

  6. Immediate effects of somatosensory stimulation on hand function in patients with poststroke hemiparesis: a randomized cross-over trial.

    PubMed

    Sim, Sun-Mi; Oh, Duck-Won; Chon, Seung-chul

    2015-12-01

    This study aimed to determine the immediate effects of somatosensory stimulation on hand function in patients with poststroke hemiparesis. Eleven patients with poststroke hemiparesis participated in this study. Four types (no stimulation, vibration, and light and rough touches) of somatosensory stimulation were performed randomly for 4 days applying only one type of somatosensory stimulation each day. The box and block test (BBT), the Jebsen-Taylor hand function test (JTHFT), hand grip strength (HGS), and movement distance and peak velocity of the wrist joint during a forward-reaching task were measured. The BBT and JTHFT scores for no stimulation [BBT: median (interquartile range), 0.00 (-1.00 to 1.00) and JTHFT: 2.57 (-0.47 to 4.92)] were significantly different from those for vibration [BBT: 3.00 (2.00-5.00) and JTHFT: -16.02 (-23.06 to -4.31)], light touch [BBT: 3.00 (1.00-4.00) and JTHFT: -5.00 (-21.20 to -0.94)], and rough touch [BBT: 2.00 (1.00-4.00) and JTHFT: -6.19 (-18.22 to -3.70)]. The JTHFT score was significantly higher for vibration than that for rough touch (P<0.05). The increase in HGS was significantly greater for light touch than that for no stimulation (P<0.05) and for vibration than that for light touch (P<0.05). There were significant differences for the sagittal and coronal planes in movement distance and for the sagittal and horizontal planes in peak velocity during the forward-reaching task (P<0.05). The findings suggest that somatosensory stimulation may be advantageous to improve the hand function of patients with poststroke hemiparesis, with more favorable effects observed in vibration stimulation.

  7. A trade-off between somatosensory and auditory related brain activity during object naming but not reading.

    PubMed

    Seghier, Mohamed L; Hope, Thomas M H; Prejawa, Susan; Parker Jones, 'Ōiwi; Vitkovitch, Melanie; Price, Cathy J

    2015-03-18

    The parietal operculum, particularly the cytoarchitectonic area OP1 of the secondary somatosensory area (SII), is involved in somatosensory feedback. Using fMRI with 58 human subjects, we investigated task-dependent differences in SII/OP1 activity during three familiar speech production tasks: object naming, reading and repeatedly saying "1-2-3." Bilateral SII/OP1 was significantly suppressed (relative to rest) during object naming, to a lesser extent when repeatedly saying "1-2-3" and not at all during reading. These results cannot be explained by task difficulty but the contrasting difference between naming and reading illustrates how the demands on somatosensory activity change with task, even when motor output (i.e., production of object names) is matched. To investigate what determined SII/OP1 deactivation during object naming, we searched the whole brain for areas where activity increased as that in SII/OP1 decreased. This across subject covariance analysis revealed a region in the right superior temporal sulcus (STS) that lies within the auditory cortex, and is activated by auditory feedback during speech production. The tradeoff between activity in SII/OP1 and STS was not observed during reading, which showed significantly more activation than naming in both SII/OP1 and STS bilaterally. These findings suggest that, although object naming is more error prone than reading, subjects can afford to rely more or less on somatosensory or auditory feedback during naming. In contrast, fast and efficient error-free reading places more consistent demands on both types of feedback, perhaps because of the potential for increased competition between lexical and sublexical codes at the articulatory level. PMID:25788691

  8. Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs.

    PubMed

    Mahoney, Jeannette R; Molholm, Sophie; Butler, John S; Sehatpour, Pejman; Gomez-Ramirez, Manuel; Ritter, Walter; Foxe, John J

    2015-01-01

    Correlated sensory inputs coursing along the individual sensory processing hierarchies arrive at multisensory convergence zones in cortex where inputs are processed in an integrative manner. The exact hierarchical level of multisensory convergence zones and the timing of their inputs are still under debate, although increasingly, evidence points to multisensory integration (MSI) at very early sensory processing levels. While MSI is said to be governed by stimulus properties including space, time, and magnitude, violations of these rules have been documented. The objective of the current study was to determine, both psychophysically and electrophysiologically, whether differential visual-somatosensory (VS) integration patterns exist for stimuli presented to the same versus opposite hemifields. Using high-density electrical mapping and complementary psychophysical data, we examined multisensory integrative processing for combinations of visual and somatosensory inputs presented to both left and right spatial locations. We assessed how early during sensory processing VS interactions were seen in the event-related potential and whether spatial alignment of the visual and somatosensory elements resulted in differential integration effects. Reaction times to all VS pairings were significantly faster than those to the unisensory conditions, regardless of spatial alignment, pointing to engagement of integrative multisensory processing in all conditions. In support, electrophysiological results revealed significant differences between multisensory simultaneous VS and summed V + S responses, regardless of the spatial alignment of the constituent inputs. Nonetheless, multisensory effects were earlier in the aligned conditions, and were found to be particularly robust in the case of right-sided inputs (beginning at just 55 ms). In contrast to previous work on audio-visual and audio-somatosensory inputs, the current work suggests a degree of spatial specificity to the earliest

  9. A Trade-Off between Somatosensory and Auditory Related Brain Activity during Object Naming But Not Reading

    PubMed Central

    Hope, Thomas M.H.; Prejawa, Susan; Parker Jones, ‘Ōiwi; Vitkovitch, Melanie; Price, Cathy J.

    2015-01-01

    The parietal operculum, particularly the cytoarchitectonic area OP1 of the secondary somatosensory area (SII), is involved in somatosensory feedback. Using fMRI with 58 human subjects, we investigated task-dependent differences in SII/OP1 activity during three familiar speech production tasks: object naming, reading and repeatedly saying “1-2-3.” Bilateral SII/OP1 was significantly suppressed (relative to rest) during object naming, to a lesser extent when repeatedly saying “1-2-3” and not at all during reading. These results cannot be explained by task difficulty but the contrasting difference between naming and reading illustrates how the demands on somatosensory activity change with task, even when motor output (i.e., production of object names) is matched. To investigate what determined SII/OP1 deactivation during object naming, we searched the whole brain for areas where activity increased as that in SII/OP1 decreased. This across subject covariance analysis revealed a region in the right superior temporal sulcus (STS) that lies within the auditory cortex, and is activated by auditory feedback during speech production. The tradeoff between activity in SII/OP1 and STS was not observed during reading, which showed significantly more activation than naming in both SII/OP1 and STS bilaterally. These findings suggest that, although object naming is more error prone than reading, subjects can afford to rely more or less on somatosensory or auditory feedback during naming. In contrast, fast and efficient error-free reading places more consistent demands on both types of feedback, perhaps because of the potential for increased competition between lexical and sublexical codes at the articulatory level. PMID:25788691

  10. Intraoperative monitoring of somatosensory-evoked potential in the spinal cord rectification operation by means of wavelet analysis

    NASA Astrophysics Data System (ADS)

    Liu, W.; Du, M. H.; Chan, Francis H. Y.; Lam, F. K.; Luk, D. K.; Hu, Y.; Fung, Kan S. M.; Qiu, W.

    1998-09-01

    Recently there has been a considerable interest in the use of a somatosensory evoked potential (SEP) for monitoring the functional integrity of the spinal cord during surgery such as spinal scoliosis. This paper describes a monitoring system and signal processing algorithms, which consists of 50 Hz mains filtering and a wavelet signal analyzer. Our system allows fast detection of changes in SEP peak latency, amplitude and signal waveform, which are the main parameters of interest during intra-operative procedures.

  11. A trade-off between somatosensory and auditory related brain activity during object naming but not reading.

    PubMed

    Seghier, Mohamed L; Hope, Thomas M H; Prejawa, Susan; Parker Jones, 'Ōiwi; Vitkovitch, Melanie; Price, Cathy J

    2015-03-18

    The parietal operculum, particularly the cytoarchitectonic area OP1 of the secondary somatosensory area (SII), is involved in somatosensory feedback. Using fMRI with 58 human subjects, we investigated task-dependent differences in SII/OP1 activity during three familiar speech production tasks: object naming, reading and repeatedly saying "1-2-3." Bilateral SII/OP1 was significantly suppressed (relative to rest) during object naming, to a lesser extent when repeatedly saying "1-2-3" and not at all during reading. These results cannot be explained by task difficulty but the contrasting difference between naming and reading illustrates how the demands on somatosensory activity change with task, even when motor output (i.e., production of object names) is matched. To investigate what determined SII/OP1 deactivation during object naming, we searched the whole brain for areas where activity increased as that in SII/OP1 decreased. This across subject covariance analysis revealed a region in the right superior temporal sulcus (STS) that lies within the auditory cortex, and is activated by auditory feedback during speech production. The tradeoff between activity in SII/OP1 and STS was not observed during reading, which showed significantly more activation than naming in both SII/OP1 and STS bilaterally. These findings suggest that, although object naming is more error prone than reading, subjects can afford to rely more or less on somatosensory or auditory feedback during naming. In contrast, fast and efficient error-free reading places more consistent demands on both types of feedback, perhaps because of the potential for increased competition between lexical and sublexical codes at the articulatory level.

  12. Interaction of gustatory and lingual somatosensory perceptions at the cortical level in the human: a functional magnetic resonance imaging study.

    PubMed

    Cerf-Ducastel, B; Van de Moortele, P F; MacLeod, P; Le Bihan, D; Faurion, A

    2001-05-01

    The present study has investigated interaction at the cortical level in the human between two major components of flavor perception, pure chemical gustatory and lingual somatosensory perception. Twelve subjects participated in a functional magnetic resonance imaging study and tasted six stimuli, applied on the whole tongue, among which four were pure gustatory stimuli (NaCl, aspartame, quinine and HCl, pH 2.4 or 2.2) and two were both taste and lingual somatosensory stimuli, i.e. somato-gustatory stimuli (HCl, pH 1.6 or 1.5, and aluminum potassium sulfate). Functional images were acquired with an echo planar sequence on a 3 T system and were individually processed by correlation with the temporal perception profile. Both sets of stimuli showed activation in the same cortical areas, namely the insula, the rolandic operculum (base of the pre- and post-central gyri), the frontal operculum and the temporal operculum, confirming a wide overlap of taste and lingual somatosensory representations. However, the relative activation across areas and the analysis of co-activated areas across all runs for each set of stimuli allowed discrimination of taste and somatosensory modalities. Factor analysis of correspondences indicated different patterns of activation across the sub-insular and opercular regions, depending on the gustatory or somato-gustatory nature of the stimuli. For gustatory stimuli different activation patterns for the superior and inferior parts of the insula suggested a difference in function between these two insular sub-regions. Furthermore, the left inferior insula was co-activated with the left angular gyrus, a structure involved in semantic processing. In contrast, only somato-gustatory stimuli specifically produced a simultaneous and symmetrical activation of both the left and right rolandic opercula, which include a part of the sensory homunculus dedicated to the tactile representation of oral structures.

  13. Transient Receptor Potential Channel Polymorphisms Are Associated with the Somatosensory Function in Neuropathic Pain Patients

    PubMed Central

    Baron, Ralf; Maier, Christoph; Tölle, Thomas R.; Treede, Rolf-Detlef; Berthele, Achim; Faltraco, Frank; Flor, Herta; Gierthmühlen, Janne; Haenisch, Sierk; Huge, Volker; Magerl, Walter; Maihöfner, Christian; Richter, Helmut; Rolke, Roman; Scherens, Andrea; Üçeyler, Nurcan; Ufer, Mike; Wasner, Gunnar; Zhu, Jihong; Cascorbi, Ingolf

    2011-01-01

    Transient receptor potential channels are important mediators of thermal and mechanical stimuli and play an important role in neuropathic pain. The contribution of hereditary variants in the genes of transient receptor potential channels to neuropathic pain is unknown. We investigated the frequency of transient receptor potential ankyrin 1, transient receptor potential melastin 8 and transient receptor potential vanilloid 1 single nucleotide polymorphisms and their impact on somatosensory abnormalities in neuropathic pain patients. Within the German Research Network on Neuropathic Pain (Deutscher Forscbungsverbund Neuropathischer Schmerz) 371 neuropathic pain patients were phenotypically characterized using standardized quantitative sensory testing. Pyrosequencing was employed to determine a total of eleven single nucleotide polymorphisms in transient receptor potential channel genes of the neuropathic pain patients and a cohort of 253 German healthy volunteers. Associations of quantitative sensory testing parameters and single nucleotide polymorphisms between and within groups and subgroups, based on sensory phenotypes, were analyzed. Single nucleotide polymorphisms frequencies did not differ between both the cohorts. However, in neuropathic pain patients transient receptor potential ankyrin 1 710G>A (rs920829, E179K) was associated with the presence of paradoxical heat sensation (p = 0.03), and transient receptor potential vanilloid 1 1911A>G (rs8065080, I585V) with cold hypoalgesia (p = 0.0035). Two main subgroups characterized by preserved (1) and impaired (2) sensory function were identified. In subgroup 1 transient receptor potential vanilloid 1 1911A>G led to significantly less heat hyperalgesia, pinprick hyperalgesia and mechanical hypaesthesia (p = 0.006, p = 0.005 and p<0.001) and transient receptor potential vanilloid 1 1103C>G (rs222747, M315I) to cold hypaesthesia (p = 0.002), but there was absence of associations in subgroup 2. In

  14. Somatosensory cortex functional connectivity abnormalities in autism show opposite trends, depending on direction and spatial scale

    PubMed Central

    Khan, Sheraz; Michmizos, Konstantinos; Tommerdahl, Mark; Ganesan, Santosh; Kitzbichler, Manfred G.; Zetino, Manuel; Garel, Keri-Lee A.; Herbert, Martha R.; Hämäläinen, Matti S.

    2015-01-01

    Functional connectivity is abnormal in autism, but the nature of these abnormalities remains elusive. Different studies, mostly using functional magnetic resonance imaging, have found increased, decreased, or even mixed pattern functional connectivity abnormalities in autism, but no unifying framework has emerged to date. We measured functional connectivity in individuals with autism and in controls using magnetoencephalography, which allowed us to resolve both the directionality (feedforward versus feedback) and spatial scale (local or long-range) of functional connectivity. Specifically, we measured the cortical response and functional connectivity during a passive 25-Hz vibrotactile stimulation in the somatosensory cortex of 20 typically developing individuals and 15 individuals with autism, all males and right-handed, aged 8–18, and the mu-rhythm during resting state in a subset of these participants (12 per group, same age range). Two major significant group differences emerged in the response to the vibrotactile stimulus. First, the 50-Hz phase locking component of the cortical response, generated locally in the primary (S1) and secondary (S2) somatosensory cortex, was reduced in the autism group (P < 0.003, corrected). Second, feedforward functional connectivity between S1 and S2 was increased in the autism group (P < 0.004, corrected). During resting state, there was no group difference in the mu-α rhythm. In contrast, the mu-β rhythm, which has been associated with feedback connectivity, was significantly reduced in the autism group (P < 0.04, corrected). Furthermore, the strength of the mu-β was correlated to the relative strength of 50 Hz component of the response to the vibrotactile stimulus (r = 0.78, P < 0.00005), indicating a shared aetiology for these seemingly unrelated abnormalities. These magnetoencephalography-derived measures were correlated with two different behavioural sensory processing scores (P < 0.01 and P < 0.02 for the autism

  15. Vestibular and Somatosensory Covergence in Postural Equilibrium Control: Insights from Spaceflight and Bed Rest Studies

    NASA Technical Reports Server (NTRS)

    Mulavara, A. P.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Peters, B. T.; Phillips, T.; Platts, S. H.; Ploutz-Snyder, L. L.; Reschke, M. F.; Ryder, J. W.; Stenger, M. B.; Taylor, L. C.; Bloomberg, J. J.

    2014-01-01

    The goal of the Functional Task Test study is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. We are currently conducting studies on both International Space Station (ISS) astronauts experiencing up to 6 months of microgravity and subjects experiencing 70 days of 6??head-down bed-rest as an analog for space flight. Bed-rest provides the opportunity for us to investigate the role of prolonged axial body unloading in isolation from the other physiological effects produced by exposure to the microgravity environment of space flight. This allows us to parse out the contribution of the body unloading somatosensory component on functional performance. Both ISS crewmembers and bed-rest subjects were tested using a protocol that evaluated functional performance along with tests of postural and locomotor control before and after space flight and bed-rest, respectively. Functional tests included ladder climbing, hatch opening, jump down, manual manipulation of objects and tool use, seat egress and obstacle avoidance, recovery from a fall, and object translation tasks. Astronauts were tested three times before flight, and on 1, 6, and 30 days after landing. Bed-rest subjects were tested three times before bed-rest and immediately after getting up from bed-rest as well as 1, 6, and 12 days after re-ambulation. A comparison of bed-rest and space flight data showed a significant concordance in performance changes across all functional tests. Tasks requiring a greater demand for dynamic control of postural equilibrium (i.e. fall recovery, seat egress/obstacle avoidance during walking, object translation, jump down) showed the greatest decrement in performance. Functional tests with reduced requirements for postural stability showed less reduction in performance. Results indicate that body unloading

  16. Exposure to Music and Noise During Pregnancy Influences Neurogenesis and Thickness in Motor and Somatosensory Cortex of Rat Pups

    PubMed Central

    Kim, Chang-Hee; Lee, Sang-Chul; Shin, Je Wook; Chung, Kyung-Jin; Lee, Shin-Ho; Shin, Mal-Soon; Baek, Sang-Bin; Sung, Yun-Hee; Kim, Chang-Ju

    2013-01-01

    Purpose Prenatal environmental conditions affect the development of the fetus. In the present study, we investigated the effects of exposure to music and noise during pregnancy on neurogenesis and thickness in the motor and somatosensory cortex of rat pups. Methods The pregnant rats in the music-applied group were exposed to 65 dB of comfortable music for 1 hour, once per day, from the 15th day of pregnancy until delivery. The pregnant rats in the noise-applied group were exposed to 95 dB of sound from a supersonic sound machine for 1 hour, once per day, from the 15th day of pregnancy until delivery. After birth, the offspring were left undisturbed together with their mother. The rat pups were sacrificed at 21 days after birth. Results Exposure to music during pregnancy increased neurogenesis in the motor and somatosensory cortex of rat pups. In contrast, rat pups exposed to noise during pregnancy showed decreased neurogenesis and thickness in the motor and somatosensory cortex. Conclusions Our study suggests that music and noise during the developmental period are important factors influencing brain development and urogenital disorders. PMID:24143288

  17. Have Confidence in Contact

    ERIC Educational Resources Information Center

    Crisp, Richard J.; Turner, Rhiannon N.

    2010-01-01

    In an article in the May-June 2009 "American Psychologist," we discussed a new approach to reducing prejudice and encouraging more positive intergroup relations (Crisp & Turner, 2009). We named the approach imagined intergroup contact and defined it as "the mental simulation of a social interaction with a member or members of an outgroup category"…

  18. The Language Contact Profile

    ERIC Educational Resources Information Center

    Freed, Barbara F.; Dewey, Dan P.; Segalowitz, Norman; Halter, Randall

    2004-01-01

    Efforts to gather data of various sorts--demographics, language-learning history, contact with native speakers, use of the language in the field--as they relate to participants in SLA research studies are inherent to understanding more about language acquisition and use. Scholars frequently develop questionnaires of their own, which are rarely…

  19. Thermal Contact Conductance

    NASA Technical Reports Server (NTRS)

    Salerno, Louis J.; Kittel, Peter

    1997-01-01

    The performance of cryogenic instruments is often a function of their operating temperature. Thus, designers of cryogenic instruments often are required to predict the operating temperature of each instrument they design. This requires accurate thermal models of cryogenic components which include the properties of the materials and assembly techniques used. When components are bolted or otherwise pressed together, a knowledge of the thermal performance of such joints are also needed. In some cases, the temperature drop across these joints represents a significant fraction of the total temperature difference between the instrument and its cooler. While extensive databases exist on the thermal properties of bulk materials, similar databases for pressed contacts do not. This has often lead to instrument designs that avoid pressed contacts or to the over-design of such joints at unnecessary expense. Although many people have made measurements of contact conductances at cryogenic temperatures, this data is often very narrow in scope and even more often it has not been published in an easily retrievable fashion, if published at all. This paper presents a summary of the limited pressed contact data available in the literature.

  20. [Contact allergies in musicians].

    PubMed

    Gasenzer, E R; Neugebauer, E A M

    2012-12-01

    During the last years, the problem of allergic diseases has increased. Allergies are errant immune responses to a normally harmless substance. In musicians the allergic contact dermatitis to exotic woods is a special problem. Exotic rosewood contains new flavonoids, which trigger an allergic reaction after permanent contact with the instrument. High quality woodwind instruments such as baroque flute or clarinets are made in ebony or palisander because of its great sound. Today instruments for non-professional players are also made in these exotic materials and non-professionals may have the risk to develop contact dermatitis, too. Brass-player has the risk of an allergic reaction to the different metals contained in the metal sheets of modern flutes and brass instruments. Specially nickel and brass alloys are used to product flute tubes or brass instruments. Special problem arises in children: patients who are allergic to plants or foods have a high risk to develop contact dermatitis. Parents don't know the materials of low-priced instruments for beginners. Often unknown cheap woods from exotic areas are used. Low-priced brass instruments contain high amount of brass and other cheap metals. Physicians should advice musician-patients or parents about the risks of the different materials and look for the reason of eczema on mouth, face, or hands. PMID:23233303

  1. Contact sensitivity to proflavine.

    PubMed

    Goh, C L

    1986-09-01

    Proflavine lotion is a commonly used topical antiseptic in the tropics, but its sensitizing potential was never emphasized and many who developed allergic contact dermatitis were never aware of it. In a study of 45 patients, most presented with acute or subacute dermatitis which started on the arms and legs. Concomitant cutaneous sensitivity to other medicaments and lanolin occurred in 66% of the patients.

  2. [Current contact allergens].

    PubMed

    Geier, J; Uter, W; Lessmann, H; Schnuch, A

    2011-10-01

    Ever-changing exposure to contact allergens, partly due to statutory directives (e.g. nickel, chromate, methyldibromo glutaronitrile) or recommendations from industrial associations (e.g. hydroxyisohexyl 3-cyclohexene carboxaldehyde), requires on-going epidemiologic surveillance of contact allergy. In this paper, the current state with special focus in fragrances and preservatives is described on the basis of data of the Information Network of Departments of Dermatology (IVDK) of the year 2010. In 2010, 12,574 patients were patch tested in the dermatology departments belonging to the IVDK. Nickel is still the most frequent contact allergen. However the continuously improved EU nickel directive already has some beneficial effect; sensitization frequency in young women is dropping. In Germany, chromate-reduced cement has been in use now for several years, leading to a decline in chromate sensitization in brick-layers. Two fragrance mixes are part of the German baseline series; they are still relevant. The most important fragrances in these mixes still are oak moss absolute and hydroxyisohexyl 3-cyclohexene carboxaldehyde. However, in relation to these leading allergens, sensitization frequency to other fragrances contained in the mixes seems to be increasing. Among the preservatives, MCI/MI has not lost its importance as contact allergen, in contrast to MDBGN. Sources of MCI/MI sensitization obviously are increasingly found in occupational context. Methylisothiazolinone is a significant allergen in occupational settings, and less frequently in body care products.

  3. Contact Efflorescence on Demand

    NASA Astrophysics Data System (ADS)

    Davis, R. D.; Lance, S.; Gordon, J. A.; Ushijima, S.; Tolbert, M. A.

    2014-12-01

    The phase state of atmospheric aerosols (liquid vs solid) plays an important role in particle growth, cloud formation, climate impact and visibility degradation. In the atmosphere, changes in relative humidity (RH) and temperature cause phase transitions in the atmospheric particulate. Efflorescence, the process of salt crystal nucleation from an aqueous electrolyte solution upon decreasing RH, often occurs at a lower RH than the reverse process of deliquescence. It has been shown that the efflorescence RH can occur at a higher RH in the presence of a heterogeneous surface immersed in a liquid particle. Here we present a new laboratory technique using optically levitated particles to study heterogeneous efflorescence initiated by contact with an external particle. In this work, collisions between aqueous microdroplets and heterogeneous nuclei are monitored in situ using scattered laser light to quantify the number of collisions and to detect phase transitions. We find that when contact initiates the phase transition, efflorescence occurs at a higher RH than when the same heterogeneous nucleus is immersed in the particle. The results of these experiments will be discussed in the context of understanding contact nucleation on a mechanistic level and predicting the relative importance of contact efflorescence in the atmosphere.

  4. Multigrid contact detection method

    NASA Astrophysics Data System (ADS)

    He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

    2007-03-01

    Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.

  5. Compact contacting device

    NASA Technical Reports Server (NTRS)

    Acharya, Arun (Inventor); Gottzmann, Christian F. (Inventor); Lockett, Michael J. (Inventor); Schneider, James S. (Inventor); Victor, Richard A. (Inventor); Zawierucha, Robert (Inventor)

    1994-01-01

    An apparatus comprising a rotatable mass of structured packing for mass or heat transfer between two contacting fluids of different densities wherein the packing mass is made up of corrugated sheets of involute shape relative to the axis of the packing mass and form a logarithmic spiral curved counter to the direction of rotation.

  6. [Contact allergies in musicians].

    PubMed

    Gasenzer, E R; Neugebauer, E A M

    2012-12-01

    During the last years, the problem of allergic diseases has increased. Allergies are errant immune responses to a normally harmless substance. In musicians the allergic contact dermatitis to exotic woods is a special problem. Exotic rosewood contains new flavonoids, which trigger an allergic reaction after permanent contact with the instrument. High quality woodwind instruments such as baroque flute or clarinets are made in ebony or palisander because of its great sound. Today instruments for non-professional players are also made in these exotic materials and non-professionals may have the risk to develop contact dermatitis, too. Brass-player has the risk of an allergic reaction to the different metals contained in the metal sheets of modern flutes and brass instruments. Specially nickel and brass alloys are used to product flute tubes or brass instruments. Special problem arises in children: patients who are allergic to plants or foods have a high risk to develop contact dermatitis. Parents don't know the materials of low-priced instruments for beginners. Often unknown cheap woods from exotic areas are used. Low-priced brass instruments contain high amount of brass and other cheap metals. Physicians should advice musician-patients or parents about the risks of the different materials and look for the reason of eczema on mouth, face, or hands.

  7. Contact: Releasing the news

    NASA Astrophysics Data System (ADS)

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  8. Toward patient-specific articular contact mechanics

    PubMed Central

    Ateshian, Gerard A.; Henak, Corinne R.; Weiss, Jeffrey A.

    2015-01-01

    The mechanics of contacting cartilage layers is fundamentally important to understanding the development, homeostasis and pathology of diarthrodial joints. Because of the highly nonlinear nature of both the materials and the contact problem itself, numerical methods such as the finite element method are typically incorporated to obtain solutions. Over the course of five decades, we have moved from an initial qualitative understanding of articular cartilage material behavior to the ability to perform complex, three-dimensional contact analysis, including multiphasic material representations. This history includes the development of analytical and computational contact analysis methods that now provide the ability to perform highly nonlinear analyses. Numerical implementations of contact analysis based on the finite element method are rapidly advancing and will soon enable patient-specific analysis of joint contact mechanics using models based on medical image data. In addition to contact stress on the articular surfaces, these techniques can predict variations in strain and strain through the cartilage layers, providing the basis to predict damage and failure. This opens up exciting areas for future research and application to patient-specific diagnosis and treatment planning applied to a variety of pathologies that affect joint function and cartilage homeostasis. PMID:25698236

  9. Resistivity of Rotated Graphite-Graphene Contacts.

    PubMed

    Chari, Tarun; Ribeiro-Palau, Rebeca; Dean, Cory R; Shepard, Kenneth

    2016-07-13

    Robust electrical contact of bulk conductors to two-dimensional (2D) material, such as graphene, is critical to the use of these 2D materials in practical electronic devices. Typical metallic contacts to graphene, whether edge or areal, yield a resistivity of no better than 100 Ω μm but are typically >10 kΩ μm. In this Letter, we employ single-crystal graphite for the bulk contact to graphene instead of conventional metals. The graphite contacts exhibit a transfer length up to four-times longer than in conventional metallic contacts. Furthermore, we are able to drive the contact resistivity to as little as 6.6 Ω μm(2) by tuning the relative orientation of the graphite and graphene crystals. We find that the contact resistivity exhibits a 60° periodicity corresponding to crystal symmetry with additional sharp decreases around 22° and 39°, which are among the commensurate angles of twisted bilayer graphene.

  10. Toward patient-specific articular contact mechanics.

    PubMed

    Ateshian, Gerard A; Henak, Corinne R; Weiss, Jeffrey A

    2015-03-18

    The mechanics of contacting cartilage layers is fundamentally important to understanding the development, homeostasis and pathology of diarthrodial joints. Because of the highly nonlinear nature of both the materials and the contact problem itself, numerical methods such as the finite element method are typically incorporated to obtain solutions. Over the course of five decades, we have moved from an initial qualitative understanding of articular cartilage material behavior to the ability to perform complex, three-dimensional contact analysis, including multiphasic material representations. This history includes the development of analytical and computational contact analysis methods that now provide the ability to perform highly nonlinear analyses. Numerical implementations of contact analysis based on the finite element method are rapidly advancing and will soon enable patient-specific analysis of joint contact mechanics using models based on medical image data. In addition to contact stress on the articular surfaces, these techniques can predict variations in strain and strain through the cartilage layers, providing the basis to predict damage and failure. This opens up exciting areas for future research and application to patient-specific diagnosis and treatment planning applied to a variety of pathologies that affect joint function and cartilage homeostasis.

  11. The embodiment of emotion: language use during the feeling of social emotions predicts cortical somatosensory activity

    PubMed Central

    Saxbe, Darby E.; Yang, Xiao-Fei; Borofsky, Larissa A.

    2013-01-01

    Complex social emotions involve both abstract cognitions and bodily sensations, and individuals may differ on their relative reliance on these. We hypothesized that individuals’ descriptions of their feelings during a semi-structured emotion induction interview would reveal two distinct psychological styles—a more abstract, cognitive style and a more body-based, affective style—and that these would be associated with somatosensory neural activity. We examined 28 participants’ open-ended verbal responses to admiration- and compassion-provoking narratives in an interview and BOLD activity to the same narratives during subsequent functional magnetic resonance imaging scanning. Consistent with hypotheses, individuals’ affective and cognitive word use were stable across emotion conditions, negatively correlated and unrelated to reported emotion strength in the scanner. Greater use of affective relative to cognitive words predicted more activation in SI, SII, middle anterior cingulate cortex and insula during emotion trials. The results suggest that individuals’ verbal descriptions of their feelings reflect differential recruitment of neural regions supporting physical body awareness. Although somatosensation has long been recognized as an important component of emotion processing, these results offer ‘proof of concept’ that individual differences in open-ended speech reflect different processing styles at the neurobiological level. This study also demonstrates SI involvement during social emotional experience. PMID:22798396

  12. Repetitive Transcranial Magnetic Stimulation of the Primary Somatosensory Cortex Modulates Perception of the Tendon Vibration Illusion.

    PubMed

    Huh, D C; Lee, J M; Oh, S M; Lee, J-H; Van Donkelaar, P; Lee, D H

    2016-10-01

    The effect of repetitive transcranial magnetic stimulation on kinesthetic perception, when applied to the somatosensory cortex, was examined. Further, the facilitatory and inhibitory effects of repetitive transcranial magnetic stimulation using different stimulation frequencies were tested. Six female (M age = 32.0 years, SD = 6.7) and nine male (M age = 32.9 years, SD = 6.6) participants were asked to perceive the tendon vibration illusion of the left wrist joint and to replicate the illusion with their right hand. When comparing changes in the corresponding movement amplitude and velocity after three different repetitive transcranial magnetic stimulation protocols (sham, 1 Hz inhibitory, and 5 Hz facilitatory repetitive transcranial magnetic stimulation), the movement amplitude was found to decrease with the inhibitory repetitive transcranial magnetic stimulation, while the movement velocity respectively increased and decreased with the facilitatory and inhibitory repetitive transcranial magnetic stimulation. These results confirmed the modulating effects of repetitive transcranial magnetic stimulation on kinesthetic perception in a single experimental paradigm. PMID:27516411

  13. Flumazenil antagonizes the suppressive effect of midazolam on the somatosensory evoked potentials in the rat.

    PubMed Central

    Suzuki, N.; Hirose, Y.; Katakura, N.; Kubota, Y.

    1991-01-01

    The effect of flumazenil, a specific benzodiazepine antagonist, on the midazolam-induced suppression of somatosensory evoked potentials (SEPs) following strong electrical stimulation of the upper lip was investigated in Wistar albino rats. The averaged SEPs were recorded from the contralateral surface of the skull in the temporal area. Each rat received midazolam in a dose of 10 mg/kg intraperitoneally. Five min after midazolam injection, the relative amplitude of the P1N1 wave of the SEPs was reduced significantly. A 0.5 mg dose of flumazenil or physiological saline was injected intraperitoneally 7.5 min after midazolam injection. The P1N1 amplitude recovered rapidly to the control value in the flumazenil group but not in the physiological saline group. No significant differences were found in the latencies of the P1 and N1 peaks before or after midazolam or flumazenil injection. It is suggested that flumazenil strongly antagonizes the midazolam-induced suppression of SEPs in the rat. PMID:1809048

  14. Monitoring of Motor and Somatosensory Evoked Potentials During Spine Surgery: Intraoperative Changes and Postoperative Outcomes

    PubMed Central

    2016-01-01

    Objective To evaluate whether the combination of muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials (SEPs) measured during spinal surgery can predict immediate and permanent postoperative motor deficits. Methods mMEP and SEP was monitored in patients undergoing spinal surgery between November 2012 and July 2014. mMEPs were elicited by a train of transcranial electrical stimulation over the motor cortex and recorded from the upper/lower limbs. SEPs were recorded by stimulating the tibial and median nerves. Results Combined mMEP/SEP recording was successfully achieved in 190 operations. In 117 of these, mMEPs and SEPs were stable and 73 showed significant changes. In 20 cases, motor deficits in the first 48 postoperative hours were observed and 6 patients manifested permanent neurological deficits. The two potentials were monitored in a number of spinal surgeries. For surgery on spinal deformities, the sensitivity and specificity of combined mMEP/SEP monitoring were 100% and 92.4%, respectively. In the case of spinal cord tumor surgeries, sensitivity was only 50% but SEP changes were observed preceding permanent motor deficits in some cases. Conclusion Intraoperative monitoring is a useful tool in spinal surgery. For spinal deformity surgery, combined mMEP/SEP monitoring showed high sensitivity and specificity; in spinal tumor surgery, only SEP changes predicted permanent motor deficits. Therefore, mMEP, SEP, and joint monitoring may all be appropriate and beneficial for the intraoperative monitoring of spinal surgery. PMID:27446784

  15. Tactile texture signals in primate primary somatosensory cortex and their relation to subjective roughness intensity.

    PubMed

    Bourgeon, Stéphanie; Dépeault, Alexandra; Meftah, El-Mehdi; Chapman, C Elaine

    2016-04-01

    This study investigated the hypothesis that a simple intensive code, based on mean firing rate, could explain the cortical representation of subjective roughness intensity and its invariance with scanning speed. We examined the sensitivity of neurons in the cutaneous, finger representation of primary somatosensory cortex (S1) to a wide range of textures [1 mm high, raised-dot surfaces; spatial periods (SPs), 1.5-8.5 mm], scanned under the digit tips at different speeds (40-115 mm/s). Since subjective roughness estimates show a monotonic increase over this range and are independent of speed, we predicted that the mean firing rate of a subgroup of S1 neurons would share these properties. Single-unit recordings were made in four alert macaques (areas 3b, 1 and 2). Cells whose discharge rate showed a monotonic increase with SP, independent of speed, were particularly concentrated in area 3b. Area 2 was characterized by a high proportion of cells sensitive to speed, with or without texture sensitivity. Area 1 had intermediate properties. We suggest that area 3b and most likely area 1 play a key role in signaling roughness intensity, and that a mean rate code, signaled by both slowly and rapidly adapting neurons, is present at the level of area 3b. Finally, the substantial proportion of neurons that showed a monotonic change in discharge limited to a small range of SPs (often independent of response saturation) could play a role in discriminating smaller changes in SP. PMID:26763776

  16. Quantitative analysis of somatosensory cortex development in metatherians and monotremes, with comparison to the laboratory rat.

    PubMed

    Ashwell, Ken W S

    2015-01-01

    Metatherians and monotremes are born in an immature state, followed by prolonged nurturing by maternal lactation. Quantitative analysis of isocortical sections held in the collections at the Museum für Naturkunde, Berlin was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness between metatherian groups, monotremes, and the laboratory rat. Analysis indicated that the pace of pallial growth in the monotremes is much lower than that in the metatherians or laboratory rat, with an estimated 8.6-fold increase in parietal cortex thickness between 10 and 100 mm body length, compared to a 10- to 20-fold increase among the metatherians and the rat. It was found that aggregation of cortical plate neurons occurs at similar embryo size in the mammals studied (around 8-14 mm body length) and a similar pallial thickness (around 200 µm), but that proliferative zone involution occurs at a much higher body size and pallial thickness in the monotremes compared to the metatherians and the laboratory rat. The observations suggest that cortical development in the monotremes is slower and subject to different regulatory signals to the therians studied. The slow pace may be related to either generally slower metabolism in monotremes or less efficient nutrient supply to the offspring due to the lack of teats. PMID:25393314

  17. Quantitative analysis of somatosensory cortex development in eutherians, with a comparison with metatherians and monotremes.

    PubMed

    Ashwell, Ken W S

    2015-01-01

    Extant eutherians exhibit a wide range of adult brain sizes and degree of cortical gyrification. Quantitative analysis of parietal isocortical sections held in museum collections was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness among diverse eutherian embryos, foetuses, and neonates. Analysis indicated that, for most eutherians, cortical plate aggregation begins at about 6-18 mm greatest length or about 120-320 µm pallial thickness. Expansion of the proliferative compartment occurs at a similar pace in most eutherians, but exceptionally rapidly in hominoids. Involution of the pallial proliferative zones occurs over a wide range of body sizes (42 mm to over 500 mm greatest length) or when the cerebral cortex reaches a thickness of 1.2-9.8 mm depending on the eutherian group. Many of these values overlap with those for metatherians. The findings suggest that there is less evolutionary flexibility in the timing of cortical plate aggregation than in the rate of expansion of the pallial proliferative compartment and the duration of proliferative zone activity. PMID:25884290

  18. Glutamate receptor blockade at cortical synapses disrupts development of thalamocortical and columnar organization in somatosensory cortex.

    PubMed Central

    Fox, K; Schlaggar, B L; Glazewski, S; O'Leary, D D

    1996-01-01

    The segregation of thalamocortical inputs into eye-specific stripes in the developing cat or monkey visual cortex is prevented by manipulations that perturb or abolish neural activity in the visual pathway. Such findings show that proper development of the functional organization of visual cortex is dependent on normal patterns of neural activity. The generalisation of this conclusion to other sensory cortices has been questioned by findings that the segregation of thalamocortical afferents into a somatotopic barrel pattern in developing rodent primary somatosensory cortex (S1) is not prevented by activity blockade. We show that a temporary block of N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors in rat S1 during the critical period for barrel development disrupts the topographic refinement of thalamocortical connectivity and columnar organization. These effects are evident well after the blockade is ineffective and thus may be permanent. Our findings show that neural activity and specifically the activation of postsynaptic cortical neurons has a prominent role in establishing the primary sensory map in S1, as well as the topographic organization of higher order synaptic connections. Images Fig. 1 PMID:8643619

  19. Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects

    SciTech Connect

    Fox, P.T.; Raichle, M.E.

    1986-02-01

    Coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) was studied using multiple sequential administrations of VO-labeled radiotracers and positron emission tomography. In the resting state an excellent correlation between CBF and CMRO2 was found when paired measurements of CBF and CMRO2 from multiple (30-48) brain regions were tested in each of 33 normal subjects. Regional uncoupling of CBF and CMRO2 was found, however, during neuronal activation induced by somatosensory stimulation. Stimulus-induced focal augmentation of cerebral blood flow (29% mean) far exceeded the concomitant local increase in tissue metabolic rate (mean, 5%), when resting-state and stimulated-state measurements were obtained in each of 9 subjects. Stimulus duration had no significant effect on response magnitude or on the degree of CBF-CMRO2 uncoupling observed. Dynamic, physiological regulation of CBF by a mechanism (neuronal or biochemical) dependent on neuronal firing per se, but independent of the cerebral metabolic rate of oxygen, is hypothesized.

  20. Time-frequency component analysis of somatosensory evoked potentials in rats

    PubMed Central

    Zhang, Zhi-Guo; Yang, Jun-Lin; Chan, Shing-Chow; Luk, Keith Dip-Kei; Hu, Yong

    2009-01-01

    Background Somatosensory evoked potential (SEP) signal usually contains a set of detailed temporal components measured and identified in a time domain, giving meaningful information on physiological mechanisms of the nervous system. The purpose of this study is to measure and identify detailed time-frequency components in normal SEP using time-frequency analysis (TFA) methods and to obtain their distribution pattern in the time-frequency domain. Methods This paper proposes to apply a high-resolution time-frequency analysis algorithm, the matching pursuit (MP), to extract detailed time-frequency components of SEP signals. The MP algorithm decomposes a SEP signal into a number of elementary time-frequency components and provides a time-frequency parameter description of the components. A clustering by estimation of the probability density function in parameter space is followed to identify stable SEP time-frequency components. Results Experimental results on cortical SEP signals of 28 mature rats show that a series of stable SEP time-frequency components can be identified using the MP decomposition algorithm. Based on the statistical properties of the component parameters, an approximated distribution of these components in time-frequency domain is suggested to describe the complex SEP response. Conclusion This study shows that there is a set of stable and minute time-frequency components in SEP signals, which are revealed by the MP decomposition and clustering. These stable SEP components have specific localizations in the time-frequency domain. PMID:19203394

  1. Referral of Touch and Ownership between the Hands and the Role of the Somatosensory Cortices

    PubMed Central

    Schaefer, Michael; Konczak, Franziska; Heinze, Hans-Jochen; Rotte, Michael

    2013-01-01

    Recent studies have shown that the feeling of body ownership can be fooled by simple visuo-tactile manipulations. Perceptual illusions have been reported in which participants sense phantom touch seen on a rubber hand (rubber hand illusion). While previous studies used homologous limbs for those experiments, we here examined an illusion where people feel phantom touch on a left rubber hand when they see it brushed simultaneously with brushes applied to their right hand. Thus, we investigated a referral of touch from the right to the left hand (across the body midline). Since it is known from animal studies that tactile illusions may alter early sensory processing, we expected a modulation of the primary somatosensory cortex (SI) corresponding to this illusion. Neuromagnetic source imaging of the functional topographic organization in SI showed a shift in left SI, associated with the strength of the referral of touch. Hence, we argue that SI seems to be closely associated with this perceptual illusion. The results suggest that the transfer of tactile information across the body midline could be mediated by neurons with bilateral tactile receptive fields (most likely BA2). PMID:23300992

  2. Quantitative analysis of somatosensory cortex development in metatherians and monotremes, with comparison to the laboratory rat.

    PubMed

    Ashwell, Ken W S

    2015-01-01

    Metatherians and monotremes are born in an immature state, followed by prolonged nurturing by maternal lactation. Quantitative analysis of isocortical sections held in the collections at the Museum für Naturkunde, Berlin was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness between metatherian groups, monotremes, and the laboratory rat. Analysis indicated that the pace of pallial growth in the monotremes is much lower than that in the metatherians or laboratory rat, with an estimated 8.6-fold increase in parietal cortex thickness between 10 and 100 mm body length, compared to a 10- to 20-fold increase among the metatherians and the rat. It was found that aggregation of cortical plate neurons occurs at similar embryo size in the mammals studied (around 8-14 mm body length) and a similar pallial thickness (around 200 µm), but that proliferative zone involution occurs at a much higher body size and pallial thickness in the monotremes compared to the metatherians and the laboratory rat. The observations suggest that cortical development in the monotremes is slower and subject to different regulatory signals to the therians studied. The slow pace may be related to either generally slower metabolism in monotremes or less efficient nutrient supply to the offspring due to the lack of teats.

  3. Quantitative analysis of somatosensory cortex development in eutherians, with a comparison with metatherians and monotremes.

    PubMed

    Ashwell, Ken W S

    2015-01-01

    Extant eutherians exhibit a wide range of adult brain sizes and degree of cortical gyrification. Quantitative analysis of parietal isocortical sections held in museum collections was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness among diverse eutherian embryos, foetuses, and neonates. Analysis indicated that, for most eutherians, cortical plate aggregation begins at about 6-18 mm greatest length or about 120-320 µm pallial thickness. Expansion of the proliferative compartment occurs at a similar pace in most eutherians, but exceptionally rapidly in hominoids. Involution of the pallial proliferative zones occurs over a wide range of body sizes (42 mm to over 500 mm greatest length) or when the cerebral cortex reaches a thickness of 1.2-9.8 mm depending on the eutherian group. Many of these values overlap with those for metatherians. The findings suggest that there is less evolutionary flexibility in the timing of cortical plate aggregation than in the rate of expansion of the pallial proliferative compartment and the duration of proliferative zone activity.

  4. Somatosensory areas of manatee cerebral cortex: histochemical characterization and functional implications.

    PubMed

    Sarko, D K; Reep, R L

    2007-01-01

    A histochemical and cytoarchitectural analysis was completed for the neocortex of the Florida manatee in order to localize primary sensory areas and particularly primary somatosensory cortex (SI). Based on the location of cytochrome oxidase-dense staining in flattened cortex preparations, preliminary functional divisions were assigned for SI with the face represented laterally followed by the flipper, body and tail representations proceeding medially. The neonate exhibited four distinct patches in the frontoparietal cortex (presumptive SI), whereas juvenile and adult specimens demonstrated a distinct pattern in which cytochrome oxidase-dense staining appeared to be blended into one large patch extending dorsomedially. This differential staining between younger versus older more developed animals was also seen on coronal sections stained for cytochrome oxidase, myelin, or Nissl bodies. These were systematically analyzed in order to accurately localize the laminar and cytoarchitectural extent of cytochrome oxidase staining. Overall, SI appears to span seven cytoarchitectural areas to which we have assigned presumptive functional representations based on the relative locations of cytochrome oxidase-dense staining. PMID:16912474

  5. Being watched: the effect of social self-focus on interoceptive and exteroceptive somatosensory perception.

    PubMed

    Durlik, Caroline; Cardini, Flavia; Tsakiris, Manos

    2014-04-01

    We become aware of our bodies interoceptively, by processing signals arising from within the body, and exteroceptively, by processing signals arising on or outside the body. Recent research highlights the importance of the interaction of exteroceptive and interoceptive signals in modulating bodily self-consciousness. The current study investigated the effect of social self-focus, manipulated via a video camera that was facing the participants and that was either switched on or off, on interoceptive sensitivity (using a heartbeat perception task) and on tactile perception (using the Somatic Signal Detection Task (SSDT)). The results indicated a significant effect of self-focus on SSDT performance, but not on interoception. SSDT performance was not moderated by interoceptive sensitivity, although interoceptive sensitivity scores were positively correlated with false alarms, independently of self-focus. Together with previous research, our results suggest that self-focus may exert different effects on body perception depending on its mode (private versus social). While interoception has been previously shown to be enhanced by private self-focus, the current study failed to find an effect of social self-focus on interoceptive sensitivity, instead demonstrating that social self-focus improves exteroceptive somatosensory processing.

  6. Interhemispheric Plasticity Protects the Deafferented Somatosensory Cortex from Functional Takeover After Nerve Injury

    PubMed Central

    Koretsky, Alan P.

    2014-01-01

    Abstract Functional changes across brain hemispheres have been reported after unilateral cortical or peripheral nerve injury. Interhemispheric callosal connections usually underlie this cortico-cortical plasticity. However, the effect of the altered callosal inputs on local cortical plasticity in the adult brain is not well studied. Ipsilateral functional magnetic resonance imaging (fMRI) activation has been reliably detected in the deafferented barrel cortex (BC) at 2 weeks after unilateral infraorbital denervation (IO) in adult rats. The ipsilateral fMRI signal relies on callosal-mediated interhemispheric plasticity. This form of interhemispheric plasticity provides a good chronic model to study the interaction between callosal inputs and local cortical plasticity. The receptive field of forepaw in the primary somatosensory cortex (S1), which is adjacent to the BC, was mapped with fMRI. The S1 receptive field expanded to take over a portion of the BC in 2 weeks after both ascending inputs and callosal inputs were removed in IO rats with ablated contralateral BC (IO+ablation). This expansion, estimated specifically by fMRI mapping, is significantly larger than what has been observed in the IO rats with intact callosal connectivity, as well as in the rats with sham surgery. This work indicates that altered callosal inputs prevent the functional takeover of the deafferented BC from adjacent cortices and may help preserve the functional identity of the BC. PMID:25117691

  7. The embodiment of emotion: language use during the feeling of social emotions predicts cortical somatosensory activity.

    PubMed

    Saxbe, Darby E; Yang, Xiao-Fei; Borofsky, Larissa A; Immordino-Yang, Mary Helen

    2013-10-01

    Complex social emotions involve both abstract cognitions and bodily sensations, and individuals may differ on their relative reliance on these. We hypothesized that ind