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Sample records for dual somatosensory input

  1. Morning/Evening differences in somatosensory inputs for postural control.

    PubMed

    Bougard, Clément; Davenne, Damien

    2014-01-01

    The underlying processes responsible for the differences between morning and afternoon measurements of postural control have not yet been clearly identified. This study was conducted to specify the role played by vestibular, visual, and somatosensory inputs in postural balance and their link with the diurnal fluctuations of body temperature and vigilance level. Nineteen healthy male subjects (mean age: 20.5 ± 1.3 years) participated in test sessions at 6:00 a.m. and 6:00 p.m. after a normal night's sleep. Temperature was measured before the subjects completed a sign cancellation test and a postural control evaluation with eyes both open and closed. Our results confirmed that postural control improved throughout the day according to the circadian rhythm of body temperature and sleepiness/vigilance. The path length as a function of surface ratio increased between 6:00 a.m. and 6:00 p.m. This is due to a decrease in the centre-of-pressure surface area, which is associated with an increase in path length. Romberg's index did not change throughout the day; however, the spectral analysis (fast Fourier transform) of the centre-of-pressure excursions (in anteroposterior and mediolateral directions) indicated that diurnal fluctuations in postural control may occur via changes in the different processes responsible for readjustment via muscle contractions.

  2. Callosal projections in rat somatosensory cortex are altered by early removal of afferent input.

    PubMed Central

    Koralek, K A; Killackey, H P

    1990-01-01

    During the first postnatal week, the distribution of callosal projection neurons in the rat somatosensory cortex changes from a uniform to a discontinuous pattern. To determine if this change is influenced by afferent inputs to the somatosensory cortex, the effect of both early unilateral infraorbital nerve section and unilateral removal of the dorsal thalamus on the distribution of callosal projections in rat somatosensory cortex was examined. One month after either of the above manipulations at birth, the tangential distribution of callosal projections in the somatosensory cortex was examined using the combined retrograde and anterograde transport of horseradish peroxidase. Both manipulations alter the distribution of callosal projection neurons and terminations in the somatosensory cortex. After infraorbital nerve section, the distribution of callosal projections is altered in the contralateral primary somatosensory cortex. The abnormalities observed are consistent with the altered distribution of thalamocortical projections. In addition, consistent abnormalities were observed in the pattern of callosal projections of the second somatosensory area of both hemispheres. Most notably, they are absent in a portion of the region that contains the representation of the mystacial vibrissae and sinus hairs in this area. Thalamic ablation resulted in highly aberrant patterns of callosal projections in the somatosensory cortex on the operated side, where abnormal bands and clusters of callosal projections were observed in apparently random locations. These results are interpreted as evidence that both peripheral and central inputs influence the maturational changes in the distribution of callosal projection neurons. Images PMID:2304906

  3. A mutant with bilateral whisker to barrel inputs unveils somatosensory mapping rules in the cerebral cortex.

    PubMed

    Renier, Nicolas; Dominici, Chloe; Erzurumlu, Reha S; Kratochwil, Claudius F; Rijli, Filippo M; Gaspar, Patricia; Chédotal, Alain

    2017-03-28

    In mammals, tactile information is mapped topographically onto the contralateral side of the brain in the primary somatosensory cortex (S1). Here we describe that in Robo3 mouse mutants a sizeable fraction of the trigemino-thalamic inputs project ipsilaterally rather than contralaterally. The resulting mixture of crossed and uncrossed sensory inputs creates bilateral whisker maps in the thalamus and cortex. Surprisingly, these maps are segregated resulting in a duplication of whisker representations and a doubling of the number of barrels without changes of the S1 size. Sensory deprivation shows competitive interactions between the ipsi/contralateral whisker maps. This study reveals that the somatosensory system can form a somatotopic map to integrate bilateral sensory inputs but organizes the maps in a different way than in the visual, or auditory systems. Therefore, while the molecular pre-patterning constrains their orientation and position, the preservation of the continuity of inputs defines the layout of the somatosensory maps.

  4. Somatosensory Anticipatory Alpha Activity Increases to Suppress Distracting Input

    ERIC Educational Resources Information Center

    Haegens, Saskia; Luther, Lisa; Jensen, Ole

    2012-01-01

    Effective processing of sensory input in daily life requires attentional selection and amplification of relevant input and, just as importantly, attenuation of irrelevant information. It has been proposed that top-down modulation of oscillatory alpha band activity (8-14 Hz) serves to allocate resources to various regions, depending on task…

  5. Locomotor adaptation and aftereffects in patients with reduced somatosensory input due to peripheral neuropathy.

    PubMed

    Bunday, Karen L; Bronstein, Adolfo M

    2009-12-01

    We studied 12 peripheral neuropathy patients (PNP) and 13 age-matched controls with the "broken escalator" paradigm to see how somatosensory loss affects gait adaptation and the release and recovery ("braking") of the forward trunk overshoot observed during this locomotor aftereffect. Trunk displacement, foot contact signals, and leg electromyograms (EMGs) were recorded while subjects walked onto a stationary sled (BEFORE trials), onto the moving sled (MOVING or adaptation trials), and again onto the stationary sled (AFTER trials). PNP were unsteady during the MOVING trials, but this progressively improved, indicating some adaptation. During the after trials, 77% of control subjects displayed a trunk overshoot aftereffect but over half of the PNP (58%) did not. The PNP without a trunk aftereffect adapted to the MOVING trials by increasing distance traveled; subsequently this was expressed as increased distance traveled during the aftereffect rather than as a trunk overshoot. This clear separation in consequent aftereffects was not seen in the normal controls suggesting that, as a result of somatosensory loss, some PNP use distinctive strategies to negotiate the moving sled, in turn resulting in a distinct aftereffects. In addition, PNP displayed earlier than normal anticipatory leg EMG activity during the first after trial. Although proprioceptive inputs are not critical for the emergence or termination of the aftereffect, somatosensory loss induces profound changes in motor adaptation and anticipation. Our study has found individual differences in adaptive motor performance, indicative that PNP adopt different feed-forward gait compensatory strategies in response to peripheral sensory loss.

  6. Dual motion valve with single motion input

    NASA Technical Reports Server (NTRS)

    Belew, Robert (Inventor)

    1987-01-01

    A dual motion valve includes two dual motion valve assemblies with a rotary input which allows the benefits of applying both rotary and axial motion to a rotary sealing element with a plurality of ports. The motion of the rotary sealing element during actuation provides axial engagement of the rotary sealing element with a stationary valve plate which also has ports. Fluid passages are created through the valve when the ports of the rotary sealing element are aligned with the ports of the stationary valve plate. Alignment is achieved through rotation of the rotary sealing element with respect to the stationary valve plate. The fluid passages provide direct paths which minimize fluid turbulence created in the fluid as it passes through the valve.

  7. Plasticity of somatosensory inputs to the cochlear nucleus--implications for tinnitus.

    PubMed

    Shore, S E

    2011-11-01

    This chapter reviews evidence for functional connections of the somatosensory and auditory systems at the very lowest levels of the nervous system. Neural inputs from the dosal root and trigeminal ganglia, as well as their brain stem nuclei, cuneate, gracillis and trigeminal, terminate in the cochlear nuclei. Terminations are primarily in the shell regions surrounding the cochlear nuclei but some terminals are found in the magnocellular regions of cochlear nucleus. The effects of stimulating these inputs on multisensory integration are shown as short and long-term, both suppressive and enhancing. Evidence that these projections are glutamatergic and are altered after cochlear damage is provided in the light of probable influences on the modulation and generation of tinnitus.

  8. Plasticity of somatosensory inputs to the cochlear nucleus – implications for tinnitus

    PubMed Central

    Shore, S.E.

    2011-01-01

    This chapter reviews evidence for functional connections of the somatosensory and auditory systems at the very lowest levels of the nervous system. Neural inputs from the dosal root and trigeminal ganglia, as well as their brain stem nuclei, cuneate, gracillis and trigeminal, terminate in the cochlear nuclei. Terminations are primarily in the shell regions surrounding the cochlear nuclei but some terminals are found in the magnocellular regions of cochlear nucleus. The effects of stimulating these inputs on multisensory integration are shown as short and long-term, both suppressive and enhancing. Evidence that these projections are glutamatergic and are altered after cochlear damage is provided in the light of probable influences on the modulation and generation of tinnitus. PMID:21620940

  9. Locomotor Adaptation and Aftereffects in Patients With Reduced Somatosensory Input Due to Peripheral Neuropathy

    PubMed Central

    Bunday, Karen L.

    2009-01-01

    We studied 12 peripheral neuropathy patients (PNP) and 13 age-matched controls with the “broken escalator” paradigm to see how somatosensory loss affects gait adaptation and the release and recovery (“braking”) of the forward trunk overshoot observed during this locomotor aftereffect. Trunk displacement, foot contact signals, and leg electromyograms (EMGs) were recorded while subjects walked onto a stationary sled (BEFORE trials), onto the moving sled (MOVING or adaptation trials), and again onto the stationary sled (AFTER trials). PNP were unsteady during the MOVING trials, but this progressively improved, indicating some adaptation. During the after trials, 77% of control subjects displayed a trunk overshoot aftereffect but over half of the PNP (58%) did not. The PNP without a trunk aftereffect adapted to the MOVING trials by increasing distance traveled; subsequently this was expressed as increased distance traveled during the aftereffect rather than as a trunk overshoot. This clear separation in consequent aftereffects was not seen in the normal controls suggesting that, as a result of somatosensory loss, some PNP use distinctive strategies to negotiate the moving sled, in turn resulting in a distinct aftereffects. In addition, PNP displayed earlier than normal anticipatory leg EMG activity during the first after trial. Although proprioceptive inputs are not critical for the emergence or termination of the aftereffect, somatosensory loss induces profound changes in motor adaptation and anticipation. Our study has found individual differences in adaptive motor performance, indicative that PNP adopt different feed-forward gait compensatory strategies in response to peripheral sensory loss. PMID:19741105

  10. Interaction of tactile input in the human primary and secondary somatosensory cortex--a magnetoencephalographic study.

    PubMed

    Hoechstetter, K; Rupp, A; Stancák, A; Meinck, H M; Stippich, C; Berg, P; Scherg, M

    2001-09-01

    Interaction of simultaneous tactile input at two finger sites in primary (SI) and secondary somatosensory cortex (SII) was studied by whole-head magnetoencephalography. Short pressure pulses were delivered to fingers of the right and left hand at an interstimulus interval of 1.6 s. The first phalanx of the left digit 1 and four other sites were stimulated either separately or simultaneously. We compared four sites with increasing distance: the second phalanx of left digit 1, left digit 5, and digits 1 and 5 of the right hand. The temporal evolution of source activity in the contralateral SI and bilateral SII was calculated using spatiotemporal source analysis. Interaction was assessed by comparing the source activity during simultaneous stimulation with the sum of the source activities elicited by separate stimulation. Significant suppressive interaction was observed in contralateral SI only for stimuli at the same hand, decreasing with distance. In SII, all digits of the same and the opposite hand interacted significantly with left digit 1. When stimulating bilaterally, SII source waveforms closely resembled the time course of the response to separate stimulation of the opposite hand. Thus, in bilateral simultaneous stimulation, the contralateral input arriving first in SII appeared to inhibit the later ipsilateral input. Similarly, the separate response to input at two unilateral finger sites which arrived slightly earlier in SII dominated the simultaneous response. Our results confirm previous findings of considerable overlap in the cortical hand representation in SII and illustrate hemispheric specialization to contralateral input when simultaneous stimuli occur bilaterally.

  11. 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.

  12. Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs

    PubMed Central

    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

  13. 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

  14. Modulatory effects of movement sequence preparation and covert spatial attention on early somatosensory input to non-primary motor areas.

    PubMed

    Brown, Matt J N; Staines, W Richard

    2015-02-01

    Early frontal somatosensory evoked potentials (SEPs) (i.e., N30) are known to be modulated by movement. Furthermore, individuals with prefrontal lesions have enhanced early frontal SEPs. However, it is currently unclear through what mechanism the prefrontal cortex may modulate early frontal SEPs. The current study investigated whether prefrontal modulatory effects on frontal SEPs may depend on the relevancy of somatosensory input for movement (i.e., interaction with motor areas). Two experiments were conducted to determine whether selective spatial attention alone (Experiment 1-Attend and Mentally Count) or when using attended somatosensory input in the preparation of finger sequences with the limb contralateral to somatosensory stimulation (Experiment 2-Attend for Movement Preparation) could modulate SEPs. In Experiment 1, SEPs elicited by median nerve (MN) stimulation at both wrists were measured in trials when individuals attended and mentally counted vibrotactile (VibT) input at either index finger. In Experiment 2, SEPs elicited by MN stimulation at the left wrist were measured in trials when individuals used attended VibT input at the left index finger to prepare finger sequences that were contralateral to MN stimulation. In both experiments, control conditions were performed where participants received passive VibT and MN stimulation. Results from Experiment 1 confirmed that selective spatial attention alone does not modulate frontal N30 peak amplitudes. However, Experiment 2 revealed that frontal N30 peak amplitudes were decreased (i.e., gated) when individuals used attended VibT input at the left index finger to prepare contralateral finger sequences. These results support a role of sensory gating of early frontal SEPs during finger sequence preparation of the limb contralateral to MN stimulation that may result from increased activity in prefrontal, motor preparatory areas, and basal ganglia.

  15. Parallel organization of proprioceptive inputs from joint receptors to cortical somatosensory areas I and II in the cat.

    PubMed Central

    Mackie, P D; Zhang, H Q; Schmidt, R F; Rowe, M J

    1996-01-01

    1. Studies in monkeys indicate that proprioceptive and tactile inputs are conveyed from the thalamus to the primary somatosensory cortex (SI) and thence to the secondary somatosensory area (SII) in a serial scheme. In contrast, in the cat, tactile information is conveyed in parallel from the thalamus to SI and SII. The present study, in the cat, employed reversible inactivation of SI to determine whether proprioceptive inputs to SII from joint receptors depend on an indirect serial path via SI or are conveyed over a direct path from the thalamus. 2. SI and SII foci for knee joint inputs were determined with evoked potential mapping. Reversible inactivation of the SI focus by cooling had no effect on the amplitude, latency or time course of SII potentials evoked by joint inputs. There was also no consistent effect on the response levels of individual SII neurones examined during SI inactivation. Furthermore, there was no attenuation of the later components of the responses, and therefore no evidence that these depended on an indirect path to SII via SI. 3. Results demonstrate that proprioceptive inputs project directly from thalamus to SII over a pathway organized in parallel with that to SI, in contrast to the serial scheme reported for proprioceptive processing in primates. Images Figure 4 PMID:8842010

  16. 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.

  17. Short-term dynamics of causal information transfer in thalamocortical networks during natural inputs and microstimulation for somatosensory neuroprosthesis

    PubMed Central

    Semework, Mulugeta; DiStasio, Marcello

    2014-01-01

    Recording the activity of large populations of neurons requires new methods to analyze and use the large volumes of time series data thus created. Fast and clear methods for finding functional connectivity are an important step toward the goal of understanding neural processing. This problem presents itself readily in somatosensory neuroprosthesis (SSNP) research, which uses microstimulation (MiSt) to activate neural tissue to mimic natural stimuli, and has the capacity to potentiate, depotentiate, or even destroy functional connections. As the aim of SSNP engineering is artificially creating neural responses that resemble those observed during natural inputs, a central goal is describing the influence of MiSt on activity structure among groups of neurons, and how this structure may be altered to affect perception or behavior. In this paper, we demonstrate the concept of Granger causality, combined with maximum likelihood methods, applied to neural signals recorded before, during, and after natural and electrical stimulation. We show how these analyses can be used to evaluate the changing interactions in the thalamocortical somatosensory system in response to repeated perturbation. Using LFPs recorded from the ventral posterolateral thalamus (VPL) and somatosensory cortex (S1) in anesthetized rats, we estimated pair-wise functional interactions between functional microdomains. The preliminary results demonstrate input-dependent modulations in the direction and strength of information flow during and after application of MiSt. Cortico-cortical interactions during cortical MiSt and baseline conditions showed the largest causal influence differences, while there was no statistically significant difference between pre- and post-stimulation baseline causal activities. These functional connectivity changes agree with physiologically accepted communication patterns through the network, and their particular parameters have implications for both rehabilitation and brain

  18. Short-term dynamics of causal information transfer in thalamocortical networks during natural inputs and microstimulation for somatosensory neuroprosthesis.

    PubMed

    Semework, Mulugeta; DiStasio, Marcello

    2014-01-01

    Recording the activity of large populations of neurons requires new methods to analyze and use the large volumes of time series data thus created. Fast and clear methods for finding functional connectivity are an important step toward the goal of understanding neural processing. This problem presents itself readily in somatosensory neuroprosthesis (SSNP) research, which uses microstimulation (MiSt) to activate neural tissue to mimic natural stimuli, and has the capacity to potentiate, depotentiate, or even destroy functional connections. As the aim of SSNP engineering is artificially creating neural responses that resemble those observed during natural inputs, a central goal is describing the influence of MiSt on activity structure among groups of neurons, and how this structure may be altered to affect perception or behavior. In this paper, we demonstrate the concept of Granger causality, combined with maximum likelihood methods, applied to neural signals recorded before, during, and after natural and electrical stimulation. We show how these analyses can be used to evaluate the changing interactions in the thalamocortical somatosensory system in response to repeated perturbation. Using LFPs recorded from the ventral posterolateral thalamus (VPL) and somatosensory cortex (S1) in anesthetized rats, we estimated pair-wise functional interactions between functional microdomains. The preliminary results demonstrate input-dependent modulations in the direction and strength of information flow during and after application of MiSt. Cortico-cortical interactions during cortical MiSt and baseline conditions showed the largest causal influence differences, while there was no statistically significant difference between pre- and post-stimulation baseline causal activities. These functional connectivity changes agree with physiologically accepted communication patterns through the network, and their particular parameters have implications for both rehabilitation and brain

  19. Synaptic Properties of Thalamic Input to the Subgranular Layers of Primary Somatosensory and Auditory Cortices in the Mouse

    PubMed Central

    Viaene, Angela N.; Petrof, Iraklis; Sherman, S. Murray

    2011-01-01

    The classification of synaptic inputs is an essential part of understanding brain circuitry. In the present study, we examined the synaptic properties of thalamic inputs to pyramidal neurons in layers 5a, 5b, and 6 of primary somatosensory (S1) and auditory (A1) cortices in mouse thalamocortical slices. Stimulation of the ventral posterior medial nucleus (VPM) and the ventral division of the medial geniculate body (MGBv) resulted in three distinct response classes, two of which have never been described before in thalamocortical projections. Class 1A responses included synaptic depression and all-or-none responses while Class 1B responses exhibited synaptic depression and graded responses. Class 1C responses are characterized by mixed facilitation and depression as well as graded responses. Activation of metabotropic glutamate receptors was not observed in any of the response classes. We conclude that Class 1 responses can be broken up into three distinct subclasses, and that thalamic inputs to the subgranular layers of cortex may combine with other, intracortical inputs to drive their postsynaptic target cells. We also integrate these results with our recent, analogous study of thalamocortical inputs to granular and supragranular layers (Viaene et al., 2011). PMID:21900553

  20. Do Visual and Vestibular Inputs Compensate for Somatosensory Loss in the Perception of Spatial Orientation? Insights from a Deafferented Patient

    PubMed Central

    Bringoux, Lionel; Scotto Di Cesare, Cécile; Borel, Liliane; Macaluso, Thomas; Sarlegna, Fabrice R.

    2016-01-01

    The present study aimed at investigating the consequences of a massive loss of somatosensory inputs on the perception of spatial orientation. The occurrence of possible compensatory processes for external (i.e., object) orientation perception and self-orientation perception was examined by manipulating visual and/or vestibular cues. To that aim, we compared perceptual responses of a deafferented patient (GL) with respect to age-matched Controls in two tasks involving gravity-related judgments. In the first task, subjects had to align a visual rod with the gravitational vertical (i.e., Subjective Visual Vertical: SVV) when facing a tilted visual frame in a classic Rod-and-Frame Test. In the second task, subjects had to report whether they felt tilted when facing different visuo-postural conditions which consisted in very slow pitch tilts of the body and/or visual surroundings away from vertical. Results showed that, much more than Controls, the deafferented patient was fully dependent on spatial cues issued from the visual frame when judging the SVV. On the other hand, the deafferented patient did not rely at all on visual cues for self-tilt detection. Moreover, the patient never reported any sensation of tilt up to 18° contrary to Controls, hence showing that she did not rely on vestibular (i.e., otoliths) signals for the detection of very slow body tilts either. Overall, this study demonstrates that a massive somatosensory deficit substantially impairs the perception of spatial orientation, and that the use of the remaining sensory inputs available to a deafferented patient differs regarding whether the judgment concerns external vs. self-orientation. PMID:27199704

  1. Cortical inhibition of laser pain and laser-evoked potentials by non-nociceptive somatosensory input.

    PubMed

    Testani, Elisa; Le Pera, Domenica; Del Percio, Claudio; Miliucci, Roberto; Brancucci, Alfredo; Pazzaglia, Costanza; De Armas, Liala; Babiloni, Claudio; Rossini, Paolo Maria; Valeriani, Massimiliano

    2015-10-01

    Although the inhibitory action that tactile stimuli can have on pain is well documented, the precise timing of the interaction between the painful and non-painful stimuli in the central nervous system is unclear. The aim of this study was to investigate this issue by measuring the timing of the amplitude modulation of laser evoked potentials (LEPs) due to conditioning non-painful stimuli. LEPs were recorded from 31 scalp electrodes in 10 healthy subjects after painful stimulation of the right arm (C6-C7 dermatomes). Non-painful electrical stimuli were applied by ring electrodes on the second and third finger of the right hand. Electrical stimuli were delivered at +50, +150, +200 and +250 ms interstimulus intervals (ISIs) after the laser pulses. LEPs obtained without any conditioning stimulation were used as a baseline. As compared to the baseline, non-painful electrical stimulation reduced the amplitude of the vertex N2/P2 LEP component and the laser pain rating when electrical stimuli followed the laser pulses only at +150 and +200 ms ISIs. As at these ISIs the collision between the non-painful and painful input is likely to take place at the cortical level, we can conclude that the late processing of painful (thermal) stimuli is partially inhibited by the processing of non-painful (cutaneous) stimuli within the cerebral cortex. Moreover, our results do not provide evidence that non-painful inputs can inhibit pain at a lower level, including the spinal cord.

  2. Differential effects of continuous theta burst stimulation over left premotor cortex and right prefrontal cortex on modulating upper limb somatosensory input.

    PubMed

    Brown, Matt J N; Staines, W Richard

    2016-02-15

    Somatosensory evoked potentials (SEPs) represent somatosensory processing in non-primary motor areas (i.e. frontal N30 and N60) and somatosensory cortices (i.e. parietal P50). It is well-known that the premotor cortex (PMC) and prefrontal cortex (PFC) are involved in the preparation and planning of upper limb movements but it is currently unclear how they modulate somatosensory processing for upper limb motor control. In the current study, two experiments examined SEP modulations after continuous theta burst stimulation (cTBS) was used to transiently disrupt the left PMC (Experiment 1) and right PFC (Experiment 2). Both Experiment 1 (n=15) and Experiment 2 (n=16) used pre-post experimental designs. In both experiments participants performed a task requiring detection of varying amplitudes of attended vibrotactile (VibT) stimuli to the left index finger (D2) and execution of a pre-matched finger sequence with the right (contralateral) hand to specific VibT targets. During the task, SEPs were measured to median nerve (MN) stimulations time-locked during pre-stimulus (250 ms before VibT), early response selection (250 ms after VibT), late preparatory (750 ms after VibT) and execution (1250 ms VibT) phases. The key findings of Experiment 1 revealed significant decreases in N30 and N60 peak amplitudes after cTBS to PMC. In contrast, the results of Experiment 2, also found significant decreased N60 peak amplitudes as well as trends for increased N30 and P50 peak amplitudes. A direct comparison of Experiment 1 and Experiment 2 confirmed differential modulation of N30 peak amplitudes after PMC (gated) compared to PFC (enhanced) cTBS. Collectively, these results support that both the left PMC and right PFC have modulatory roles on early somatosensory input into non-primary motor areas, such as PMC and supplementary motor area (SMA), represented by frontal N30 and N60 SEPs. These results confirm that PMC and PFC are both part of a network that regulates somatosensory input

  3. Potentiation of convergent synaptic inputs onto pyramidal neurons in somatosensory cortex: dependence on brain wave frequencies and NMDA receptor subunit composition.

    PubMed

    Pilli, J; Kumar, S S

    2014-07-11

    N-methyl-d-aspartate receptors (NMDARs) at layer (L)1/primary whisker motor cortex synaptic inputs are distinct from thalamic/striatal (Str) synaptic inputs onto L5 pyramidal neurons in the rat somatosensory cortex. However, the consequences of differential expression of putative GluN3A-containing triheteromeric NMDARs at L1 inputs and GluN2A-containing diheteromeric NMDARs at Str inputs on plasticity of the underlying synapses at the respective inputs remain unknown. Here we demonstrate that L1, but not Str, synapses are potentiated following delta burst stimulation (dBS). This potentiation is blocked by d-serine and/or intracellular 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) suggesting that it is subunit-specific and dependent on elevations in intracellular Ca(2+). Interestingly, ifenprodil, the GluN2B-preferring antagonist, suppresses baseline L1 responses but does not prevent induction of dBS-evoked potentiation. Unlike L1, Str synapses are maximally potentiated following theta burst stimulation (tBS) and this potentiation is blocked with BAPTA and/or the GluN2A-preferring antagonist NVP-AAM077. We show further that while dBS is both necessary and sufficient to potentiate L1 synapses, tBS is most effective in potentiating Str synapses. Our data suggest distinct potentiating paradigms for the two convergent inputs onto pyramidal neurons in the somatosensory cortex and co-dependence of synaptic potentiation on brain wave-tuned frequencies of burst stimulation and subunit composition of underlying NMDARs. A model for predicting the likelihood of enhancing synaptic efficacy is proposed based on Ca(2+) influx through these receptors and integration of EPSPs at these inputs. Together, these findings raise the possibility of input-specific enhancements of synaptic efficacy in neurons as a function of the animal's behavioral state and/or arousal in vivo.

  4. The Dual Nature of Early-Life Experience on Somatosensory Processing in the Human Infant Brain.

    PubMed

    Maitre, Nathalie L; Key, Alexandra P; Chorna, Olena D; Slaughter, James C; Matusz, Pawel J; Wallace, Mark T; Murray, Micah M

    2017-04-03

    Every year, 15 million preterm infants are born, and most spend their first weeks in neonatal intensive care units (NICUs) [1]. Although essential for the support and survival of these infants, NICU sensory environments are dramatically different from those in which full-term infants mature and thus likely impact the development of functional brain organization [2]. Yet the integrity of sensory systems determines effective perception and behavior [3, 4]. In neonates, touch is a cornerstone of interpersonal interactions and sensory-cognitive development [5-7]. NICU treatments used to improve neurodevelopmental outcomes rely heavily on touch [8]. However, we understand little of how brain maturation at birth (i.e., prematurity) and quality of early-life experiences (e.g., supportive versus painful touch) interact to shape the development of the somatosensory system [9]. Here, we identified the spatial, temporal, and amplitude characteristics of cortical responses to light touch that differentiate them from sham stimuli in full-term infants. We then utilized this data-driven analytical framework to show that the degree of prematurity at birth determines the extent to which brain responses to light touch (but not sham) are attenuated at the time of discharge from the hospital. Building on these results, we showed that, when controlling for prematurity and analgesics, supportive experiences (e.g., breastfeeding, skin-to-skin care) are associated with stronger brain responses, whereas painful experiences (e.g., skin punctures, tube insertions) are associated with reduced brain responses to the same touch stimuli. Our results shed crucial insights into the mechanisms through which common early perinatal experiences may shape the somatosensory scaffolding of later perceptual, cognitive, and social development.

  5. Dual-Modality Input in Repeated Reading for Foreign Language Learners with Different Learning Styles

    ERIC Educational Resources Information Center

    Liu, Yeu-Ting; Todd, Andrew Graeme

    2014-01-01

    Research into dual-modality theory has long rested on the assumption that presenting input in two modalities leads to better learning outcomes. However, this may not always hold true. This study explored the possible advantages of using dual modality in repeated reading--a pedagogy often used to enhance reading development--for two literacy…

  6. Steady-state evoked potentials to study the processing of tactile and nociceptive somatosensory input in the human brain.

    PubMed

    Colon, E; Legrain, V; Mouraux, A

    2012-10-01

    The periodic presentation of a sensory stimulus induces, at certain frequencies of stimulation, a sustained electroencephalographic response of corresponding frequency, known as steady-state evoked potentials (SS-EP). In visual, auditory and vibrotactile modalities, studies have shown that SS-EP reflect mainly activity originating from early, modality-specific sensory cortices. Furthermore, it has been shown that SS-EP have several advantages over the recording of transient event-related brain potentials (ERP), such as a high signal-to-noise ratio, a shorter time to obtain reliable signals, and the capacity to frequency-tag the cortical activity elicited by concurrently presented sensory stimuli. Recently, we showed that SS-EP can be elicited by the selective activation of skin nociceptors and that nociceptive SS-EP reflect the activity of a population of neurons that is spatially distinct from the somatotopically-organized population of neurons underlying vibrotactile SS-EP. Hence, the recording of SS-EP offers a unique opportunity to study the cortical representation of nociception and touch in humans, and to explore their potential crossmodal interactions. Here, (1) we review available methods to achieve the rapid periodic stimulation of somatosensory afferents required to elicit SS-EP, (2) review previous studies that have characterized vibrotactile and nociceptive SS-EP, (3) discuss the nature of the recorded signals and their relationship with transient event-related potentials and (4) outline future perspectives and potential clinical applications of this technique.

  7. TAC-Cell inputs to human hand and lip induce short-term adaptation of the primary somatosensory cortex.

    PubMed

    Venkatesan, Lalit; Barlow, Steven; Popescu, Mihai; Popescu, Anda; Auer, Edward T

    2010-08-12

    A new pneumatic tactile stimulator, called the TAC-Cell, was developed in our laboratory to non-invasively deliver patterned cutaneous stimulation to the face and hand in order to study the neuromagnetic response adaptation patterns within the primary somatosensory cortex (S1) in young adult humans. Individual TAC-Cells were positioned on the glabrous surface of the right hand, and midline of the upper and lower lip vermilion. A 151-channel magnetoencephalography (MEG) scanner was used to record the cortical response to a novel tactile stimulus which consisted of a repeating 6-pulse train delivered at three different frequencies through the active membrane surface of the TAC-Cell. The evoked activity in S1 (contralateral for hand stimulation, and bilateral for lip stimulation) was characterized from the best-fit dipoles of the earliest prominent response component. The S1 responses manifested significant modulation and adaptation as a function of the frequency of the punctate pneumatic stimulus trains and stimulus site (glabrous lip versus glabrous hand).

  8. Research on input shaping algorithm for rapid positioning of ultra-precision dual-stage

    NASA Astrophysics Data System (ADS)

    Song, Fazhi; Wang, Yan; Chen, Xinglin; He, Ping

    2015-08-01

    As a high-precision servo motion platform, the dual-stage lithographic system uses lots of long-stroke air-bearing linear motors to achieve rapid positioning. Residual vibration, resulting from direct drive, almost zero damping, parallel decoupling structure and high velocity, leads to too long settling time and is one of the key factors in slowing the speed of positioning. To suppress the residual vibration and realize the high positioning precision in shorter settling time, this paper designs feedforward controller with input shaping algorithm for the rotary motor. Traditional input shaper is sensitive to system models and it is very difficult to get the parameters. A parameter self-learning method based on PSO(Particle Swarm Optimization) is proposed in this paper. The simulation of the system is performed by MATLAB/Simulation. The experimental results indicate that the input shaping algorithm proposed in this paper brings about significant reduction in the positioning time of the dual-stage.

  9. Somatosensory inputs by application of KinesioTaping: effects on spasticity, balance, and gait in chronic spinal cord injury

    PubMed Central

    Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco

    2014-01-01

    Introduction: Leg paralysis, spasticity, reduced interlimb coordination, and impaired balance are the chief limitations to overground ambulation in subjects with incomplete spinal cord injury (SCI). In recent years, the application of KinesioTaping (KT) has been proposed to enhance sensory inputs, decreasing spasticity by proprioception feedback and relieving abnormal muscle tension. Because no studies have examined KT-based techniques in SCI subjects, our goal was to analyze the effects of ankle joint KT on spasticity, balance, and gait. Materials and Methods: A randomized crossover case control design was used to compare the effects of KT and conventional nonelastic silk tape (ST) in 11 chronic SCI subjects, AIS level D, with soleus/gastrocnemius (S/G) muscle spasticity and balance and gait impairments. Treatment: 48 h of treatment with KT or ST was followed by 48 h with the other technique after 1 week. A single Y-strip of Cure© tape (KT) and ST was to the S and G muscles with 0% stretch. Before and 48 h after of application of KT and ST, clinical data on the range of motion (ROM), spasticity, clonus, pain, balance, and gait were collected. Stabilometric platform assessment of center of pressure (COP) movements; bidimensional gait analysis; and recording of electromyographic (EMG) activity of the S, G, and tibialis anterior and extensor hallucis lungus muscles were also performed. Results: Only KT had significant effects on spasticity (p < 0.05), clonus (p < 0.001) and COP movements (p < 0.05), kinematic gait parameters (p < 0.001), and EMG activity (p < 0.001). Comparison between ST and KT improvements pointed out significant differences as concerns ROM (p < 0.001), spasticity (p < 0.001), clonus (p < 0.001), pain (p < 0.001), COP parameters (p < 0.05), and most kinematic gait data (p < 0.05). Discussion: Short-term application of KT reduces spasticity and pain and improves balance and gait in chronic SCI subjects. Although these data are promising, they

  10. Dual-input two-compartment pharmacokinetic model of dynamic contrast-enhanced magnetic resonance imaging in hepatocellular carcinoma

    PubMed Central

    Yang, Jian-Feng; Zhao, Zhen-Hua; Zhang, Yu; Zhao, Li; Yang, Li-Ming; Zhang, Min-Ming; Wang, Bo-Yin; Wang, Ting; Lu, Bao-Chun

    2016-01-01

    AIM: To investigate the feasibility of a dual-input two-compartment tracer kinetic model for evaluating tumorous microvascular properties in advanced hepatocellular carcinoma (HCC). METHODS: From January 2014 to April 2015, we prospectively measured and analyzed pharmacokinetic parameters [transfer constant (Ktrans), plasma flow (Fp), permeability surface area product (PS), efflux rate constant (kep), extravascular extracellular space volume ratio (ve), blood plasma volume ratio (vp), and hepatic perfusion index (HPI)] using dual-input two-compartment tracer kinetic models [a dual-input extended Tofts model and a dual-input 2-compartment exchange model (2CXM)] in 28 consecutive HCC patients. A well-known consensus that HCC is a hypervascular tumor supplied by the hepatic artery and the portal vein was used as a reference standard. A paired Student’s t-test and a nonparametric paired Wilcoxon rank sum test were used to compare the equivalent pharmacokinetic parameters derived from the two models, and Pearson correlation analysis was also applied to observe the correlations among all equivalent parameters. The tumor size and pharmacokinetic parameters were tested by Pearson correlation analysis, while correlations among stage, tumor size and all pharmacokinetic parameters were assessed by Spearman correlation analysis. RESULTS: The Fp value was greater than the PS value (FP = 1.07 mL/mL per minute, PS = 0.19 mL/mL per minute) in the dual-input 2CXM; HPI was 0.66 and 0.63 in the dual-input extended Tofts model and the dual-input 2CXM, respectively. There were no significant differences in the kep, vp, or HPI between the dual-input extended Tofts model and the dual-input 2CXM (P = 0.524, 0.569, and 0.622, respectively). All equivalent pharmacokinetic parameters, except for ve, were correlated in the two dual-input two-compartment pharmacokinetic models; both Fp and PS in the dual-input 2CXM were correlated with Ktrans derived from the dual-input extended Tofts model

  11. Removal of GABAergic inhibition alters subthreshold input in neurons in forepaw barrel subfield (FBS) in rat first somatosensory cortex (SI) after digit stimulation.

    PubMed

    Li, Cheng X; Callaway, Joseph C; Waters, Robert S

    2002-08-01

    Our objective was to test the hypothesis that suppression of GABAergic inhibition results in an enhancement of responses to stimulation of the surround receptive field. Neurons in the forepaw barrel subfield (FBS) in rat first somatosensory cortex (SI) receive short latency suprathreshold input from a principal location on the forepaw and longer latency subthreshold input from surrounding forepaw skin regions. Input from principal and surround receptive field sites was examined before, during, and after administration of the GABA(A) receptor blocker bicuculline methiodide (BMI) (in 165 mM NaCl at pH 3.3-3.5). In vivo extracellular recording was used to first identify the location of the glabrous forepaw digit representation within the FBS. In vivo intracellular recording and labeling techniques were then used to impale single FBS neurons in layer IV as well as neurons in layers III and V, determine the receptive field of the cell, and fill the cell with biocytin for subsequent morphological identification. The intracellular recording electrode was fastened with dental wax to a double-barrel pipette for BMI iontophoresis and current balance. A stimulating probe, placed on the glabrous forepaw skin surface, was used to identify principal and surround components of the receptive field. Once a cell was impaled and a stable recording was obtained, a stimulating probe was placed at a selected site within the surround receptive field. Single-pulse stimulation (1 Hz) was then delivered through the skin probe and the percentage of spikes occurring in 1-min intervals before BMI onset was used as a baseline measure. BMI was then iontophoresed while the periphery was simultaneously stimulated, and spike percentage measured during and after BMI ejection was compared with the pre-BMI baseline. The major findings are: (1) suppression of GABAergic inhibition enhanced evoked responses to firing level from sites in surround receptive fields in 65% of the cells ( n=17); (2) evoked

  12. Engineering orthogonal dual transcription factors for multi-input synthetic promoters

    PubMed Central

    Brödel, Andreas K.; Jaramillo, Alfonso; Isalan, Mark

    2016-01-01

    Synthetic biology has seen an explosive growth in the capability of engineering artificial gene circuits from transcription factors (TFs), particularly in bacteria. However, most artificial networks still employ the same core set of TFs (for example LacI, TetR and cI). The TFs mostly function via repression and it is difficult to integrate multiple inputs in promoter logic. Here we present to our knowledge the first set of dual activator-repressor switches for orthogonal logic gates, based on bacteriophage λ cI variants and multi-input promoter architectures. Our toolkit contains 12 TFs, flexibly operating as activators, repressors, dual activator–repressors or dual repressor–repressors, on up to 270 synthetic promoters. To engineer non cross-reacting cI variants, we design a new M13 phagemid-based system for the directed evolution of biomolecules. Because cI is used in so many synthetic biology projects, the new set of variants will easily slot into the existing projects of other groups, greatly expanding current engineering capacities. PMID:27982027

  13. The Effect of Somatosensory and Cognitive-motor Tasks on the Paretic Leg of Chronic Stroke Patients in the Standing Posture

    PubMed Central

    Ju, Sung-kwang; Yoo, Won-gyu

    2014-01-01

    [Purpose] The purpose of this study was to investigate how different standing surfaces alter somatosensory input and how postural control is affected by these changes during the performance of a dual task with a cognitive-motor aspect. [Subjects] The subjects were 20 chronic stroke patients: 18 males, 2 females. [Methods] COP total distance, sway velocity, and the weight load on the paretic leg were measured while subjects performed the following three tasks (somatosensory task, cognitive-motor task, and dual task). [Results] Both COP total distance and sway velocity significantly decreased during the performance of all tasks. COP total distance and sway velocity significantly decreased during the somatosensory task and the dual task. The weight load significantly increased during performance of the somatosensory task and the dual task. [Conclusion] Compensatory mechanisms in the non-paretic leg were limited by placing it on an air cushion, and we observed an increase in somatosensory input from the paretic leg due to an enhanced weight load. PMID:25540484

  14. Experimental validation of optimum input polarization states for Mueller matrix determination with a dual photoelastic modulator polarimeter.

    PubMed

    Gribble, Adam; Layden, David; Vitkin, I Alex

    2013-12-15

    Dual photoelastic modulator polarimeters can measure light polarization, which is often described as a Stokes vector. By evaluating changes in polarization when light interacts with a sample, the sample Mueller matrix also can be derived, completely describing its interaction with polarized light. The choice of which and how many input Stokes vectors to use for sample investigation is under the experimenter's control. Previous work has predicted that sets of input Stokes vectors forming the vertices of platonic solids on the Poincaré sphere allow for the most robust Mueller matrix determination. Further, when errors specific to the dual photoelastic modulator polarimeter are considered, simulations revealed that one specific shape and orientation of Stokes vectors (cube on the Poincaré sphere with vertices away from principal sphere axes) allows for the most robust Mueller matrix determination. Here we experimentally validate the optimum input Stokes vectors for dual photoelastic modulator Mueller polarimetry, toward developing a robust polarimetric platform of increasing relevance to biophotonics.

  15. An Examination of Language Input and Vocabulary Development of Young Latino Dual Language Learners Living in Poverty

    ERIC Educational Resources Information Center

    Boyce, Lisa K.; Gillam, Sandra L.; Innocenti, Mark S.; Cook, Gina A.; Ortiz, Eduardo

    2013-01-01

    The purpose of the study was to evaluate the language status of 120 young, Latino dual language learners living in poverty in the United States. Maternal language input and home language and literacy environments were examined with regard to language development at 24 and 36 months. Results suggested that even when combining English and Spanish…

  16. Antagonistic control of a dual-input mammalian gene switch by food additives

    PubMed Central

    Xie, Mingqi; Ye, Haifeng; Hamri, Ghislaine Charpin-El; Fussenegger, Martin

    2014-01-01

    Synthetic biology has significantly advanced the design of mammalian trigger-inducible transgene-control devices that are able to programme complex cellular behaviour. Fruit-based benzoate derivatives licensed as food additives, such as flavours (e.g. vanillate) and preservatives (e.g. benzoate), are a particularly attractive class of trigger compounds for orthogonal mammalian transgene control devices because of their innocuousness, physiological compatibility and simple oral administration. Capitalizing on the genetic componentry of the soil bacterium Comamonas testosteroni, which has evolved to catabolize a variety of aromatic compounds, we have designed different mammalian gene expression systems that could be induced and repressed by the food additives benzoate and vanillate. When implanting designer cells engineered for gene switch-driven expression of the human placental secreted alkaline phosphatase (SEAP) into mice, blood SEAP levels of treated animals directly correlated with a benzoate-enriched drinking programme. Additionally, the benzoate-/vanillate-responsive device was compatible with other transgene control systems and could be assembled into higher-order control networks providing expression dynamics reminiscent of a lap-timing stopwatch. Designer gene switches using licensed food additives as trigger compounds to achieve antagonistic dual-input expression profiles and provide novel control topologies and regulation dynamics may advance future gene- and cell-based therapies. PMID:25030908

  17. Antagonistic control of a dual-input mammalian gene switch by food additives.

    PubMed

    Xie, Mingqi; Ye, Haifeng; Hamri, Ghislaine Charpin-El; Fussenegger, Martin

    2014-08-01

    Synthetic biology has significantly advanced the design of mammalian trigger-inducible transgene-control devices that are able to programme complex cellular behaviour. Fruit-based benzoate derivatives licensed as food additives, such as flavours (e.g. vanillate) and preservatives (e.g. benzoate), are a particularly attractive class of trigger compounds for orthogonal mammalian transgene control devices because of their innocuousness, physiological compatibility and simple oral administration. Capitalizing on the genetic componentry of the soil bacterium Comamonas testosteroni, which has evolved to catabolize a variety of aromatic compounds, we have designed different mammalian gene expression systems that could be induced and repressed by the food additives benzoate and vanillate. When implanting designer cells engineered for gene switch-driven expression of the human placental secreted alkaline phosphatase (SEAP) into mice, blood SEAP levels of treated animals directly correlated with a benzoate-enriched drinking programme. Additionally, the benzoate-/vanillate-responsive device was compatible with other transgene control systems and could be assembled into higher-order control networks providing expression dynamics reminiscent of a lap-timing stopwatch. Designer gene switches using licensed food additives as trigger compounds to achieve antagonistic dual-input expression profiles and provide novel control topologies and regulation dynamics may advance future gene- and cell-based therapies.

  18. Substitution of natural sensory input by artificial neurostimulation of an amputated trigeminal nerve does not prevent the degeneration of basal forebrain cholinergic circuits projecting to the somatosensory cortex

    PubMed Central

    Herrera-Rincon, Celia; Panetsos, Fivos

    2014-01-01

    Peripheral deafferentation downregulates acetylcholine (ACh) synthesis in sensory cortices. However, the responsible neural circuits and processes are not known. We irreversibly transected the rat infraorbital nerve and implanted neuroprosthetic microdevices for proximal stump stimulation, and assessed cytochrome-oxidase and choline- acetyl-transferase (ChAT) in somatosensory, auditory and visual cortices; estimated the number and density of ACh-neurons in the magnocellular basal nucleus (MBN); and localized down-regulated ACh-neurons in basal forebrain using retrograde labeling from deafferented cortices. Here we show that nerve transection, causes down regulation of MBN cholinergic neurons. Stimulation of the cut nerve reverses the metabolic decline but does not affect the decrease in cholinergic fibers in cortex or cholinergic neurons in basal forebrain. Artifical stimulation of the nerve also has no affect of ACh-innervation of other cortices. Cortical ChAT depletion is due to loss of corticopetal MBN ChAT-expressing neurons. MBN ChAT downregulation is not due to a decrease of afferent activity or to a failure of trophic support. Basalocortical ACh circuits are sensory specific, ACh is provided to each sensory cortex “on demand” by dedicated circuits. Our data support the existence of a modality-specific cortex-MBN-cortex circuit for cognitive information processing. PMID:25452715

  19. Intra-areal and corticocortical circuits arising in the dysgranular zone of rat primary somatosensory cortex that processes deep somatic input.

    PubMed

    Kim, Uhnoh; Lee, Taehee

    2013-08-01

    Somesthesis-guided exploration of the external world requires cortical processing of both cutaneous and proprioceptive information and their integration into motor commands to guide further haptic movement. In the past, attention has been given mostly to the cortical circuits processing cutaneous information for somatic motor integration. By comparison, little has been examined about how cortical circuits are organized for higher order proprioceptive processing. Using the rat cortex as a model, we characterized the intrinsic and corticocortical circuits arising in the major proprioceptive region of the primary somatosensory cortex (SI) that is conventionally referred to as the dysgranular zone (DSZ). We made small injections of biotinylated dextran amine (BDA) as an anterograde tracer in various parts of the DSZ, revealing three distinct principles of its cortical circuit organization. First, its intrinsic circuits extend mainly along the major axis of DSZ to organize multiple patches of interconnections. Second, the central and peripheral regions of DSZ produce differential patterns of intra-areal and corticocortical circuits. Third, the projection fields of DSZ encompass only selective regions of the second somatic (SII), posterior parietal (PPC), and primary motor (MI) cortices. These projection fields are at least partially separated from those of SI cutaneous areas. We hypothesize, based on these observations, that the cortical circuits of DSZ facilitate a modular integration of proprioceptive information along its major axis and disseminate this information to only selective parts of higher order somatic and MI cortices in parallel with cutaneous information.

  20. High serotonin levels during brain development alter the structural input-output connectivity of neural networks in the rat somatosensory layer IV

    PubMed Central

    Miceli, Stéphanie; Negwer, Moritz; van Eijs, Fenneke; Kalkhoven, Carla; van Lierop, Ilja; Homberg, Judith; Schubert, Dirk

    2013-01-01

    Homeostatic regulation of serotonin (5-HT) concentration is critical for “normal” topographical organization and development of thalamocortical (TC) afferent circuits. Down-regulation of the serotonin transporter (SERT) and the consequent impaired reuptake of 5-HT at the synapse, results in a reduced terminal branching of developing TC afferents within the primary somatosensory cortex (S1). Despite the presence of multiple genetic models, the effect of high extracellular 5-HT levels on the structure and function of developing intracortical neural networks is far from being understood. Here, using juvenile SERT knockout (SERT−/−) rats we investigated, in vitro, the effect of increased 5-HT levels on the structural organization of (i) the TC projections of the ventroposteromedial thalamic nucleus toward S1, (ii) the general barrel-field pattern, and (iii) the electrophysiological and morphological properties of the excitatory cell population in layer IV of S1 [spiny stellate (SpSt) and pyramidal cells]. Our results confirmed previous findings that high levels of 5-HT during development lead to a reduction of the topographical precision of TCA projections toward the barrel cortex. Also, the barrel pattern was altered but not abolished in SERT−/− rats. In layer IV, both excitatory SpSt and pyramidal cells showed a significantly reduced intracolumnar organization of their axonal projections. In addition, the layer IV SpSt cells gave rise to a prominent projection toward the infragranular layer Vb. Our findings point to a structural and functional reorganization of TCAs, as well as early stage intracortical microcircuitry, following the disruption of 5-HT reuptake during critical developmental periods. The increased projection pattern of the layer IV neurons suggests that the intracortical network changes are not limited to the main entry layer IV but may also affect the subsequent stages of the canonical circuits of the barrel cortex. PMID:23761736

  1. A dual-input nonlinear system analysis of autonomic modulation of heart rate.

    PubMed

    Chon, K H; Mullen, T J; Cohen, R J

    1996-05-01

    Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

  2. Relating Input Factors and Dual Language Proficiency in French-English Bilingual Children

    ERIC Educational Resources Information Center

    Cohen, Cathy

    2016-01-01

    The input factors that may cause variation in bilingual proficiency were investigated in 38 French-English bilinguals aged six to eight, of middle-to-high socio-economic status, attending an international state school in France. Data on children's current and cumulative language exposure and family background were collected through questionnaires…

  3. A dual-input nonlinear system analysis of autonomic modulation of heart rate

    NASA Technical Reports Server (NTRS)

    Chon, K. H.; Mullen, T. J.; Cohen, R. J.

    1996-01-01

    Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

  4. 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.

  5. Synthetic dual-input mammalian genetic circuits enable tunable and stringent transcription control by chemical and light.

    PubMed

    Chen, Xianjun; Li, Ting; Wang, Xue; Du, Zengmin; Liu, Renmei; Yang, Yi

    2016-04-07

    Programmable transcription factors can enable precise control of gene expression triggered by a chemical inducer or light. To obtain versatile transgene system with combined benefits of a chemical inducer and light inducer, we created various chimeric promoters through the assembly of different copies of the tet operator and Gal4 operator module, which simultaneously responded to a tetracycline-responsive transcription factor and a light-switchable transactivator. The activities of these chimeric promoters can be regulated by tetracycline and blue light synergistically or antagonistically. Further studies of the antagonistic genetic circuit exhibited high spatiotemporal resolution and extremely low leaky expression, which therefore could be used to spatially and stringently control the expression of highly toxic protein Diphtheria toxin A for light regulated gene therapy. When transferring plasmids engineered for the gene switch-driven expression of a firefly luciferase (Fluc) into mice, the Fluc expression levels of the treated animals directly correlated with the tetracycline and light input program. We suggest that dual-input genetic circuits using TET and light that serve as triggers to achieve expression profiles may enable the design of robust therapeutic gene circuits for gene- and cell-based therapies.

  6. Static and dynamic posture control in postlingual cochlear implanted patients: effects of dual-tasking, visual and auditory inputs suppression

    PubMed Central

    Bernard-Demanze, Laurence; Léonard, Jacques; Dumitrescu, Michel; Meller, Renaud; Magnan, Jacques; Lacour, Michel

    2014-01-01

    Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body's position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI) surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of postlingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static (stable platform) and dynamic (platform in translation) conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO) and eyes closed (EC) conditions, with the CI activated (ON) or not (OFF). Results showed that the postural performance of the CI patients strongly differed from the controls, mainly in the EC condition. The CI patients showed significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk: they behaved dynamically without vision like an inverted pendulum while the controls showed a whole body rigidification strategy. Hearing (prosthesis on) as well

  7. Gamma oscillations in the somatosensory cortex of newborn rats.

    PubMed

    Gerasimova, E V; Zakharov, A V; Lebedeva, Yu A; Inacio, A R; Minlebaev, M G; Sitdikova, G F; Khazipov, R N

    2014-01-01

    Here we addressed a question of whether gamma oscillations previously described in the whisker-related barrel cortex are a universal pattern of activity in the somatosensory cortex of newborn rats. Intracortical recording of local field potentials and action potentials in neurons using multisite silicon electrodes in 2-7-day-old rats showed that mechanical stimulation of single fingers or specific areas on the plantar or back side of the foot evoked early gamma oscillations followed by spindle-burst oscillations in the corresponding regions of the somatosensory cortex. Early gamma oscillations had maximum amplitude in layer IV of the somatosensory cortex and effectively synchronized action potentials in layer IV neurons. It was concluded that early gamma oscillations evoked by activation of the topographic sensory input are a universal activity pattern of the entire somatosensory cortex of newborn rats.

  8. The Role of Input and Output Modality Pairings in Dual-Task Performance: Evidence for Content-Dependent Central Interference

    ERIC Educational Resources Information Center

    Hazeltine, Eliot; Ruthruff, Eric; Remington, Roger W.

    2006-01-01

    Recent debate regarding dual-task performance has focused on whether costs result from limitations in central capacity, and whether central operations can be performed in parallel. While these questions are controversial, the dominant models of dual-task performance share the assumption that central operations are generic--that is, their…

  9. Cervicogenic somatosensory tinnitus: An indication for manual therapy? Part 1: Theoretical concept.

    PubMed

    Oostendorp, Rob A B; Bakker, Iem; Elvers, Hans; Mikolajewska, Emilia; Michiels, Sarah; De Hertogh, Willem; Samwel, Han

    2016-06-01

    Tinnitus can be evoked or modulated by input from the somatosensory and somatomotor systems. This means that the loudness or intensity of tinnitus can be changed by sensory or motor stimuli such as muscle contractions, mechanical pressure on myofascial trigger points, transcutaneous electrical stimulation or joint movements. The neural connections and integration of the auditory and somatosensory systems of the upper cervical region and head have been confirmed by many studies. These connections can give rise to a form of tinnitus known as somatosensory tinnitus. To date only a handful of publications have focussed on (cervicogenic) somatosensory tinnitus and manual therapy. Broadening the current understanding of somatosensory tinnitus would represent a first step towards providing therapeutic approaches relevant to manual therapists. Treatment modalities involving the somatosensory systems, and particularly manual therapy, should now be re-assessed in the subgroup of patients with cervicogenic somatosensory tinnitus. The conceptual phase of this study aims to uncover underlying mechanisms linking the auditory and somatosensory systems in relation to subjective tinnitus through (i) review of the literature (part 1) and (ii) through design of a pilot study that will explore characteristics of the study population and identify relevant components and outcomes of manual therapy in patients with cervicogenic somatosensory tinnitus (part 2). This manuscript focusses the theoretical concept of (cervicogenic) somatosensory tinnitus, either with or without secondary central tinnitus or tinnitus sensitization.

  10. Entorhinal-CA3 Dual-Input Control of Spike Timing in the Hippocampus by Theta-Gamma Coupling.

    PubMed

    Fernández-Ruiz, Antonio; Oliva, Azahara; Nagy, Gergő A; Maurer, Andrew P; Berényi, Antal; Buzsáki, György

    2017-03-08

    Theta-gamma phase coupling and spike timing within theta oscillations are prominent features of the hippocampus and are often related to navigation and memory. However, the mechanisms that give rise to these relationships are not well understood. Using high spatial resolution electrophysiology, we investigated the influence of CA3 and entorhinal inputs on the timing of CA1 neurons. The theta-phase preference and excitatory strength of the afferent CA3 and entorhinal inputs effectively timed the principal neuron activity, as well as regulated distinct CA1 interneuron populations in multiple tasks and behavioral states. Feedback potentiation of distal dendritic inhibition by CA1 place cells attenuated the excitatory entorhinal input at place field entry, coupled with feedback depression of proximal dendritic and perisomatic inhibition, allowing the CA3 input to gain control toward the exit. Thus, upstream inputs interact with local mechanisms to determine theta-phase timing of hippocampal neurons to support memory and spatial navigation.

  11. 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.

  12. A 10-bit 80-MS/s opamp-sharing pipelined ADC with a switch-embedded dual-input MDAC

    NASA Astrophysics Data System (ADS)

    Rui, Yin; Youchun, Liao; Wei, Zhang; Zhangwen, Tang

    2011-02-01

    A 10-bit 80-MS/s opamp-sharing pipelined ADC is implemented in a 0.18-μm CMOS. An opamp-sharing MDAC with a switch-embedded dual-input opamp is proposed to eliminate the non-resetting and successive-stage crosstalk problems observed in the conventional opamp-sharing technique. The ADC achieves a peak SNDR of 60.1 dB (ENOB = 9.69 bits) and a peak SFDR of 76 dB, while maintaining more than 9.6 ENOB for the full Nyquist input bandwidth. The core area of the ADC is 1.1 mm2 and the chip consumes 28 mW with a 1.8 V power supply.

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

    PubMed

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

    2016-04-04

    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.

  14. Auditory, Somatosensory, and Multisensory Insular Cortex in the Rat

    PubMed Central

    Rodgers, Krista M.; Benison, Alexander M.; Klein, Andrea

    2008-01-01

    Compared with other areas of the forebrain, the function of insular cortex is poorly understood. This study examined the unisensory and multisensory function of the rat insula using high-resolution, whole-hemisphere, epipial evoked potential mapping. We found the posterior insula to contain distinct auditory and somatotopically organized somatosensory fields with an interposed and overlapping region capable of integrating these sensory modalities. Unisensory and multisensory responses were uninfluenced by complete lesioning of primary and secondary auditory and somatosensory cortices, suggesting a high degree of parallel afferent input from the thalamus. In light of the established connections of the posterior insula with the amygdala, we propose that integration of auditory and somatosensory modalities reported here may play a role in auditory fear conditioning. PMID:18424777

  15. 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.

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

    PubMed Central

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

    2016-01-01

    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 Biol 24: 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. PMID:26888099

  17. 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

  18. New dual in-growth core isotopic technique to assess the root litter carbon input to the soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The root-derived carbon (C) input to the soil, whose quantification is often neglected because of methodological difficulties, is considered a crucial C flux for soil C dynamics and net ecosystem productivity (NEP) studies. In the present study, we compared two independent methods to quantify this C...

  19. Release-independent depression at pyramidal inputs onto specific cell targets: dual recordings in slices of rat cortex

    PubMed Central

    Thomson, Alex M; Bannister, A Peter

    1999-01-01

    Paired intracellular recordings were performed in slices of adult rat neocortex and hippocampus to examine presynaptic depression. A novel form of depression that occurs even in the absence of transmitter release during conditioning activity was observed at a subset of synaptic connections. In each pair studied, a pyramidal neurone was presynaptic and inputs onto a range of morphologically identified postsynaptic target cells were analysed; high probability connections exhibiting the more traditional forms of release-dependent depression, as well as low probability connections exhibiting facilitation, were tested (n = 35). Connections were tested with presynaptic spike pairs and trains of spikes with a range of interspike intervals. Sweeps in which the first action potential elicited no detectable response (apparent failures of transmission) and sweeps in which the first action potential elicited large EPSPs were selected. Second EPSPs that followed apparent failures were then compared with second EPSPs that followed large first EPSPs. Release-independent depression was apparent when second EPSPs at brief interspike intervals (< 10–15 ms) were on average smaller than second EPSPs at longer interspike intervals, even following apparent failures and when the second EPSP amplitude at these short intervals was independent of the amplitude of the first EPSP. Release-independent depression appeared selectively expressed. Depressing inputs onto some interneurones, such as CA1 basket-like and bistratified cells, and facilitating inputs onto others, such as some fast spiking neocortical interneurones, exhibited this phenomenon. In contrast, depressing inputs onto 10/10 neocortical pyramids and facilitating inputs onto 7/7 oriens-lacunosum moleculare and 5/5 burst firing, sparsely spiny neocortical interneurones did not. PMID:10432339

  20. Semi-intact ex vivo approach to investigate spinal somatosensory circuits

    PubMed Central

    Hachisuka, Junichi; Baumbauer, Kyle M; Omori, Yu; Snyder, Lindsey M; Koerber, H Richard; Ross, Sarah E

    2016-01-01

    The somatosensory input that gives rise to the perceptions of pain, itch, cold and heat are initially integrated in the superficial dorsal horn of the spinal cord. Here, we describe a new approach to investigate these neural circuits in mouse. This semi-intact somatosensory preparation enables recording from spinal output neurons, while precisely controlling somatosensory input, and simultaneously manipulating specific populations of spinal interneurons. Our findings suggest that spinal interneurons show distinct temporal and spatial tuning properties. We also show that modality selectivity — mechanical, heat and cold — can be assessed in both retrogradely labeled spinoparabrachial projection neurons and genetically labeled spinal interneurons. Finally, we demonstrate that interneuron connectivity can be determined via optogenetic activation of specific interneuron subtypes. This new approach may facilitate key conceptual advances in our understanding of the spinal somatosensory circuits in health and disease. DOI: http://dx.doi.org/10.7554/eLife.22866.001 PMID:27991851

  1. Somatosensory response properties of excitatory and inhibitory neurons in rat motor cortex.

    PubMed

    Murray, Peter D; Keller, Asaf

    2011-09-01

    In sensory cortical networks, peripheral inputs differentially activate excitatory and inhibitory neurons. Inhibitory neurons typically have larger responses and broader receptive field tuning compared with excitatory neurons. These differences are thought to underlie the powerful feedforward inhibition that occurs in response to sensory input. In the motor cortex, as in the somatosensory cortex, cutaneous and proprioceptive somatosensory inputs, generated before and during movement, strongly and dynamically modulate the activity of motor neurons involved in a movement and ultimately shape cortical command. Human studies suggest that somatosensory inputs modulate motor cortical activity in a center excitation, surround inhibition manner such that input from the activated muscle excites motor cortical neurons that project to it, whereas somatosensory input from nearby, nonactivated muscles inhibit these neurons. A key prediction of this hypothesis is that inhibitory and excitatory motor cortical neurons respond differently to somatosensory inputs. We tested this prediction with the use of multisite extracellular recordings in anesthetized rats. We found that fast-spiking (presumably inhibitory) neurons respond to tactile and proprioceptive inputs at shorter latencies and larger response magnitudes compared with regular-spiking (presumably excitatory) neurons. In contrast, we found no differences in the receptive field size of these neuronal populations. Strikingly, all fast-spiking neuron pairs analyzed with cross-correlation analysis displayed common excitation, which was significantly more prevalent than common excitation for regular-spiking neuron pairs. These findings suggest that somatosensory inputs preferentially evoke feedforward inhibition in the motor cortex. We suggest that this provides a mechanism for dynamic selection of motor cortical modules during voluntary movements.

  2. Dual Input AND Gate Fabricated From a Single Channel Poly (3-Hexylthiophene) Thin Film Field Effect Transistor

    NASA Technical Reports Server (NTRS)

    Pinto, N. J.; Perez, R.; Mueller, C. H.; Theofylaktos, N.; Miranda, F. A.

    2006-01-01

    A regio-regular poly (3-hexylthiophene) (RRP3HT) thin film transistor having a split-gate architecture has been fabricated on a doped silicon/silicon nitride substrate and characterized. This device demonstrates AND logic functionality. The device functionality was controlled by applying either 0 or -10 V to each of the gate electrodes. When -10 V was simultaneously applied to both gates, the device was conductive (ON), while any other combination of gate voltages rendered the device resistive (OFF). The p-type carrier charge mobility was about 5x10(exp -4) per square centimeter per V-sec. The low mobility is attributed to the sharp contours of the RRP3HT film due to substrate non-planarity. A significant advantage of this architecture is that AND logic devices with multiple inputs can be fabricated using a single RRP3HT channel with multiple gates.

  3. Bilateral representations of touch in the primary somatosensory cortex.

    PubMed

    Tamè, Luigi; Braun, Christoph; Holmes, Nicholas P; Farnè, Alessandro; Pavani, Francesco

    2016-01-01

    According to current textbook knowledge, the primary somatosensory cortex (SI) supports unilateral tactile representations, whereas structures beyond SI, in particular the secondary somatosensory cortex (SII), support bilateral tactile representations. However, dexterous and well-coordinated bimanual motor tasks require early integration of bilateral tactile information. Sequential processing, first of unilateral and subsequently of bilateral sensory information, might not be sufficient to accomplish these tasks. This view of sequential processing in the somatosensory system might therefore be questioned, at least for demanding bimanual tasks. Evidence from the last 15 years is forcing a revision of this textbook notion. Studies in animals and humans indicate that SI is more than a simple relay for unilateral sensory information and, together with SII, contributes to the integration of somatosensory inputs from both sides of the body. Here, we review a series of recent works from our own and other laboratories in favour of interactions between tactile stimuli on the two sides of the body at early stages of processing. We focus on tactile processing, although a similar logic may also apply to other aspects of somatosensation. We begin by describing the basic anatomy and physiology of interhemispheric transfer, drawing on neurophysiological studies in animals and behavioural studies in humans that showed tactile interactions between body sides, both in healthy and in brain-damaged individuals. Then we describe the neural substrates of bilateral interactions in somatosensation as revealed by neurophysiological work in animals and neuroimaging studies in humans (i.e., functional magnetic resonance imaging, magnetoencephalography, and transcranial magnetic stimulation). Finally, we conclude with considerations on the dilemma of how efficiently integrating bilateral sensory information at early processing stages can coexist with more lateralized representations of

  4. Auditory mechanics in a bush-cricket: direct evidence of dual sound inputs in the pressure difference receiver.

    PubMed

    Jonsson, Thorin; Montealegre-Z, Fernando; Soulsbury, Carl D; Robson Brown, Kate A; Robert, Daniel

    2016-09-01

    The ear of the bush-cricket, Copiphora gorgonensis, consists of a system of paired eardrums (tympana) on each foreleg. In these insects, the ear is backed by an air-filled tube, the acoustic trachea (AT), which transfers sound from the prothoracic acoustic spiracle to the internal side of the eardrums. Both surfaces of the eardrums of this auditory system are exposed to sound, making it a directionally sensitive pressure difference receiver. A key feature of the AT is its capacity to reduce the velocity of sound propagation and alter the acoustic driving forces at the tympanum. The mechanism responsible for reduction in sound velocity in the AT remains elusive, yet it is deemed to depend on adiabatic or isothermal conditions. To investigate the biophysics of such multiple input ears, we used micro-scanning laser Doppler vibrometry and micro-computed X-ray tomography. We measured the velocity of sound propagation in the AT, the transmission gains across auditory frequencies and the time-resolved mechanical dynamics of the tympanal membranes in C. gorgonensis Tracheal sound transmission generates a gain of approximately 15 dB SPL, and a propagation velocity of ca 255 m s(-1), an approximately 25% reduction from free field propagation. Modelling tracheal acoustic behaviour that accounts for thermal and viscous effects, we conclude that reduction in sound velocity within the AT can be explained, among others, by heat exchange between the sound wave and the tracheal walls.

  5. Population coding in somatosensory cortex.

    PubMed

    Petersen, Rasmus S; Panzeri, Stefano; Diamond, Mathew E

    2002-08-01

    Computational analyses have begun to elucidate which components of somatosensory cortical population activity may encode basic stimulus features. Recent results from rat barrel cortex suggest that the essence of this code is not synergistic spike patterns, but rather the precise timing of single neuron's first post-stimulus spikes. This may form the basis for a fast, robust population code.

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

    PubMed

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

    2016-08-08

    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.

  7. 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

  8. Modulation of somatosensory evoked magnetic fields by intensity of interfering stimuli in human somatosensory cortex: an MEG study.

    PubMed

    Lim, Manyoel; Kim, June Sic; Chung, Chun Kee

    2012-07-02

    Somatosensory evoked responses are known to be modulated by previous interfering stimuli. Here, we first investigated the modulatory effects of interfering stimuli with different intensities on somatosensory evoked magnetic field in human primary (S1) and secondary (S2) somatosensory cortices. In the control condition of the study, test stimulus, set to strong intensity, was delivered to the left median nerve. Interfering stimuli with three different levels of intensity from weak (WI) through moderate (MI) and finally to strong (SI) were interspersed to the left median nerve between the test stimuli in each interfering condition. The cortical responses to the test stimulus were modeled with equivalent current dipoles in the contralateral S1 and bilateral S2 cortices from 17 subjects. The amplitude of the N20m deflection from the S1 was not changed by any interfering stimuli, whereas the amplitude of later P35m deflection was reduced by MI stimulus. The amplitude of P60m deflection was reduced by MI and SI stimuli. The extent of amplitude reduction of the bilateral S2 response was markedly increased as intensity of interfering stimuli increased from weak to moderate, but further reduction by the SI stimuli compared to MI stimuli was not observed. Those results indicated that somatosensory cortical activation in the S1 (P35m and P60m) and S2 were modulated by intensity of interfering stimuli. Our findings of a greater gating effect on the bilateral S2 compared to the contralateral S1 indicate that S2 may play an important role in temporal integration of different intensity levels of somatosensory inputs.

  9. The Influence of Eye Closure on Somatosensory Discrimination: A Trade-off Between Simple Perception and Discrimination.

    PubMed

    Götz, Theresa; Hanke, David; Huonker, Ralph; Weiss, Thomas; Klingner, Carsten; Brodoehl, Stefan; Baumbach, Philipp; Witte, Otto W

    2017-04-12

    We often close our eyes to improve perception. Recent results have shown a decrease of perception thresholds accompanied by an increase in somatosensory activity after eye closure. However, does somatosensory spatial discrimination also benefit from eye closure? We previously showed that spatial discrimination is accompanied by a reduction of somatosensory activity. Using magnetoencephalography, we analyzed the magnitude of primary somatosensory (somatosensory P50m) and primary auditory activity (auditory P50m) during a one-back discrimination task in 21 healthy volunteers. In complete darkness, participants were requested to pay attention to either the somatosensory or auditory stimulation and asked to open or close their eyes every 6.5 min. Somatosensory P50m was reduced during a task requiring the distinguishing of stimulus location changes at the distal phalanges of different fingers. The somatosensory P50m was further reduced and detection performance was higher during eyes open. A similar reduction was found for the auditory P50m during a task requiring the distinguishing of changing tones. The function of eye closure is more than controlling visual input. It might be advantageous for perception because it is an effective way to reduce interference from other modalities, but disadvantageous for spatial discrimination because it requires at least one top-down processing stage.

  10. Integration of visual and somatosensory target information in goal-directed eye and arm movements.

    PubMed

    Neggers, S F; Bekkering, H

    1999-03-01

    In this study, we compared separate and coordinated eye and hand movements towards visual or somatosensory target stimuli in a dark room, where no visual position information about the hand could be obtained. Experiment 1 showed that saccadic reaction times (RTs) were longer when directed to somatosensory targets than when directed to visual targets in both single- and dual-task conditions. However, for hand movements, this pattern was only found in the dual-task condition and not in the single-task condition. Experiment 1 also showed that correlations between saccadic and hand RTs were significantly higher when directed towards somatosensory targets than when directed towards visual targets. Importantly, experiment 2 indicated that this was not caused by differences in processing times at a perceptual level. Furthermore, hand-pointing accuracy was found to be higher when subjects had to move their eyes as well (dual task) compared to a single-task hand movement. However, this effect was more pronounced for movements to visual targets than to somatosensory targets. A schematic model of sensorimotor transformations for saccadic eye and goal-directed hand movements is proposed and possible shared mechanisms of the two motor systems are discussed.

  11. Static magnetic field stimulation over parietal cortex enhances somatosensory detection in humans.

    PubMed

    Carrasco-López, Carmen; Soto-León, Vanesa; Céspedes, Virginia; Profice, Paolo; Strange, Bryan A; Foffani, Guglielmo; Oliviero, Antonio

    2017-03-09

    The role of neuronal oscillations in human somatosensory perception is currently unclear. To address this, here we employ non-invasive brain stimulation to artificially modulate cortical network dynamics in the context of neurophysiological and behavioral recordings. We demonstrate that transcranial static magnetic stimulation (tSMS) over the somatosensory parietal cortex increases oscillatory power specifically in the alpha range, without significantly affecting bottom-up thalamo-cortical inputs indexed by the early cortical component of somatosensory evoked potentials. Critically, we next show that parietal tSMS enhances the detection of near-threshold somatosensory stimuli. Interestingly, this behavioral improvement reflects a decrease of habituation to somatosensation. Our data therefore provide causal evidence that somatosensory perception depends on parietal alpha activity. Artificially increasing alpha power by placing a powerful magnetic field over the parietal cortex overcomes the natural decline in detection probability of a repeated near-threshold sensory stimulus.SignificanceStatement Artificially increasing alpha power by placing a powerful magnetic field over the somatosensory cortex overcomes the natural decline in detection probability of a repeated near-threshold sensory stimulus.

  12. Normalization in human somatosensory cortex.

    PubMed

    Brouwer, Gijs Joost; Arnedo, Vanessa; Offen, Shani; Heeger, David J; Grant, Arthur C

    2015-11-01

    Functional magnetic resonance imaging (fMRI) was used to measure activity in human somatosensory cortex and to test for cross-digit suppression. Subjects received stimulation (vibration of varying amplitudes) to the right thumb (target) with or without concurrent stimulation of the right middle finger (mask). Subjects were less sensitive to target stimulation (psychophysical detection thresholds were higher) when target and mask digits were stimulated concurrently compared with when the target was stimulated in isolation. fMRI voxels in a region of the left postcentral gyrus each responded when either digit was stimulated. A regression model (called a forward model) was used to separate the fMRI measurements from these voxels into two hypothetical channels, each of which responded selectively to only one of the two digits. For the channel tuned to the target digit, responses in the left postcentral gyrus increased with target stimulus amplitude but were suppressed by concurrent stimulation to the mask digit, evident as a shift in the gain of the response functions. For the channel tuned to the mask digit, a constant baseline response was evoked for all target amplitudes when the mask was absent and responses decreased with increasing target amplitude when the mask was concurrently presented. A computational model based on divisive normalization provided a good fit to the measurements for both mask-absent and target + mask stimulation. We conclude that the normalization model can explain cross-digit suppression in human somatosensory cortex, supporting the hypothesis that normalization is a canonical neural computation.

  13. Listening to another sense: somatosensory integration in the auditory system.

    PubMed

    Wu, Calvin; Stefanescu, Roxana A; Martel, David T; Shore, Susan E

    2015-07-01

    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.

  14. Cross-modal interactions of auditory and somatic inputs in the brainstem and midbrain and their imbalance in tinnitus and deafness

    PubMed Central

    Dehmel, S; Cui, YL; Shore, SE

    2009-01-01

    Purpose This review outlines the anatomical and functional bases of somatosensory influences on auditory processing in the normal brainstem and midbrain. Thereafter, it explores how interactions between the auditory and somatosensory system are modified through deafness and their impact on tinnitus is discussed. Methods literature-review, tract-tracing, immunohistochemistry, in vivo electrophysiological recordings Results Somatosensory input originates in the dorsal root ganglia (DRG) and trigeminal ganglia (TG) and is transmitted directly and indirectly through second order nuclei to the ventral and dorsal cochlear nucleus (VCN, DCN) and inferior colliculus (IC). The glutamatergic somatosensory afferents can be segregated from auditory nerve inputs by the type of vesicular glutamate transporters present in their terminals. Electrical stimulation of the somatosensory input results in a complex combination of excitation and inhibition and alters the rate and timing of responses to acoustic stimulation. Deafness increases the spontaneous rates of those neurons that receive excitatory somatosensory input, and results in a greater sensitivity of DCN neurons to trigeminal stimulation. Conclusions Auditory-somatosensory bimodal integration is already present in first order auditory nuclei. The balance of excitation and inhibition elicited by somatosensory input is altered following deafness. The increase in somatosensory influence on auditory neurons when their auditory input is diminished could be due to cross modal re-innervation or increased synaptic strength, and may contribute to mechanisms underlying somatic tinnitus. PMID:19056923

  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.

  16. Somatosensory disturbance by methylmercury exposure.

    PubMed

    Takaoka, Shigeru; Kawakami, Yoshinobu; Fujino, Tadashi; Oh-ishi, Fumihiro; Motokura, Fukuo; Kumagai, Yoshio; Miyaoka, Tetsu

    2008-05-01

    Minamata disease is methylmercury poisoning from consuming fish and shellfish contaminated by industrial waste. The polluted seafood was widely consumed in the area around Minamata, but many individuals were never examined for or classified as having Minamata disease. Following the determination of the Supreme Court of Japan in October 2004 that the Japanese Government was responsible for spreading Minamata disease, over 13,000 residents came forward to be examined for Minamata disease. We studied 197 residents from the Minamata area who had a history of fish consumption during the polluted period to determine the importance of sensory symptoms and findings in making a diagnosis of Minamata disease. We divided the exposed subjects into non-complicated (E) and complicated (E+N) groups based on the absence or presence of other neurological or neurologically related disorders and compared them to residents in control area (C) after matching for age and sex. We quantitatively measured four somatosensory modalities (minimal tactile sense by Semmes-Weinstein monofilaments, vibration sense, position sense, and two-point discrimination) and did psychophysical tests of fine-surface-texture discrimination. Subjective complaints were higher in groups E and E+N than C. Over 90% of E+N and E subjects displayed a sensory disturbance on conventional neurological examination and 28% had visual constriction. About 50% of the E and E +N groups had upper and lower extremity ataxia and about 70% had truncal ataxia. The prevalence of these neurological findings was significantly higher in exposed subjects than controls. All sensory modalities were impaired in the E and E+N groups. All four quantitatively measured sensory modalities were correlated. The prevalence of complaints, neurological findings, and sensory impairment was similar or a little worse in group E+N than in group E. We conclude that sensory symptoms and findings are important in making the diagnosis of Minamata disease

  17. Sensory incongruence leading to hand disownership modulates somatosensory cortical processing.

    PubMed

    Otsuru, Naofumi; Hashizume, Akira; Nakamura, Daichi; Endo, Yuuki; Inui, Koji; Kakigi, Ryusuke; Yuge, Louis

    2014-09-01

    The sense of body ownership is based on integration of multimodal sensory information, including tactile sensation, proprioception, and vision. Distorted body ownership contributes to the development of chronic pain syndromes and possibly symptoms of psychiatric disease. However, the effects of disownership on cortical processing of somatosensory information are unknown. In the present study, we created a "disownership" condition in healthy individuals by manipulating the visual information indicating the location of the subject's own left hand using a mirror box and examined the influence of this disownership on cortical responses to electrical stimulation of the left index finger using magnetoencephalography (MEG). The event-related magnetic field in the right primary somatosensory cortex at approximately 50 msec (M50) after stimulus was enhanced under the disownership condition. The present results suggest that M50 reflects a cortical incongruence detection mechanism involving integration of sensory inputs from visual and proprioceptive systems. This signal may be valuable for future studies of the mechanisms underlying sense of body ownership and the role that disrupted sense of ownership has in neurological disease.

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

    PubMed Central

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

    2012-01-01

    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. PMID:22927423

  19. 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

  20. Neurodynamics of somatosensory cortices studied by magnetoencephelography.

    PubMed

    Kishida, Kuniharu

    2013-09-01

    From the viewpoint of statistical inverse problems, identification of transfer functions in feedback models is applied for neurodynamics of somatosensory cortices, and brain communication among active regions can be expressed in terms of transfer functions. However, brain activities have been investigated mainly by averaged waveforms in the conventional magnetoencephalography analysis, and thus brain communication among active regions has not yet been identified. It is shown that brain communication among two more than three brain regions is determined, when fluctuations related to concatenate averaged waveforms can be obtained by using a suitable blind source separation method. In blind identification of feedback model, some transfer functions or their impulse responses between output variables of current dipoles corresponding to active regions are identified from reconstructed time series data of fluctuations by the method of inverse problem. Neurodynamics of somatosensory cortices in 5 Hz median nerve stimuli can be shown by cerebral communication among active regions of somatosensory cortices in terms of impulse responses of feedback model.

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

    PubMed

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

    2014-04-01

    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.

  2. Simultaneous all-optical digital comparator and dual-directional half-subtractor for two-input 40 Gbit/s DPSK signals employing SOAs

    NASA Astrophysics Data System (ADS)

    Zhang, Yin; Lei, Lei; Dong, Jianji; Zhang, Xinliang

    2012-02-01

    A module of simultaneous implementation of all-optical digital comparator and dual-directional half-subtractor is proposed. Proof-of-concept experiment is performed at 40 Gbit/s employing the four-wave mixing and cross gain modulation in three parallel semiconductor optical amplifiers. All output results with over 10 dB extinction ratios, clear and wide open eye diagrams, are obtained without using assistant/holding light beam. All-optical half-adder can also be obtained by adjusting the phase shifter of delay interferometer in the proposed module because of its inherent reconfigurability and flexibility. The module would be a promising digital logic elementary circuit in all-optical networks and computing systems.

  3. Basic properties of somatosensory-evoked responses in the dorsal hippocampus of the rat

    PubMed Central

    Bellistri, Elisa; Aguilar, Juan; Brotons-Mas, Jorge R; Foffani, Guglielmo; de la Prida, Liset Menendez

    2013-01-01

    The hippocampus is a pivotal structure for episodic memory function. This ability relies on the possibility of integrating different features of sensory stimuli with the spatio-temporal context in which they occur. While recent studies now suggest that somatosensory information is already processed by the hippocampus, the basic mechanisms still remain unexplored. Here, we used electrical stimulation of the paws, the whisker pad or the medial lemniscus to probe the somatosensory pathway to the hippocampus in the anaesthetized rat, and multisite electrodes, in combination with tetrode and intracellular recordings, to look at the properties of somatosensory hippocampal responses. We found that peripheral and lemniscal stimulation elicited small local field potential responses in the dorsal hippocampus about 35–40 ms post-stimulus. Current source density analysis established the local nature of these responses, revealing associated synaptic sinks that were consistently confined to the molecular layer (ML) of the dentate gyrus (DG), with less regular activation of the CA1 stratum lacunosum moleculare (SLM). A delayed (40–45 ms), potentially active, current source that outlasted the SLM sink was present in about 50% cases around the CA1 pyramidal cell layer. Somatosensory stimulation resulted in multi-unit firing increases in the majority of DG responses (79%), whereas multi-unit firing suppression was observed in the majority of CA1 responses (62%). Tetrode and intracellular recordings of individual cells confirmed different firing modulation in the DG and the CA1 region, and verified the active nature of both the early ML sink and delayed somatic CA1 source. Hippocampal responses to somatosensory stimuli were dependent on fluctuations in the strength and composition of synaptic inputs due to changes of the ongoing local (hippocampal) and distant (cortical) state. We conclude that somatosensory signals reach the hippocampus mainly from layer II entorhinal cortex to

  4. 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...

  5. Recurrent neural processing and somatosensory awareness.

    PubMed

    Auksztulewicz, Ryszard; Spitzer, Bernhard; Blankenburg, Felix

    2012-01-18

    The neural mechanisms of stimulus detection, despite extensive research, remain elusive. The recurrent processing hypothesis, a prominent theoretical account of perceptual awareness, states that, although stimuli might in principle evoke feedforward activity propagating through the visual cortex, stimuli that become consciously detected are further processed in feedforward-feedback loops established between cortical areas. To test this theory in the tactile modality, we applied dynamic causal modeling to electroencephalography (EEG) data acquired from humans in a somatosensory detection task. In the analysis of stimulation-induced event-related potentials (ERPs), we focused on model-based evidence for feedforward, feedback, and recurrent processing between primary and secondary somatosensory cortices. Bayesian model comparison revealed that, although early EEG components were well explained by both the feedforward and the recurrent models, the recurrent model outperformed the other models when later EEG segments were analyzed. Within the recurrent model, stimulus detection was characterized by a relatively early strength increase of the feedforward connection from primary to secondary somatosensory cortex (>80 ms). At longer latencies (>140 ms), also the feedback connection showed a detection-related strength increase. The modeling results on relative evidence between recurrent and feedforward model comparison support the hypothesis that the ERP responses from sensory areas arising after aware stimulus detection can be explained by increased recurrent processing within the somatosensory network in the later stages of stimulus processing.

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

    PubMed Central

    Uppal, Neha; Foxe, John J.; Butler, John S.; Acluche, Frantzy

    2016-01-01

    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

  7. 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

  8. The Processing of Somatosensory Information Shifts from an Early Parallel into a Serial Processing Mode: A Combined fMRI/MEG Study

    PubMed Central

    Klingner, Carsten M.; Brodoehl, Stefan; Huonker, Ralph; Witte, Otto W.

    2016-01-01

    The question regarding whether somatosensory inputs are processed in parallel or in series has not been clearly answered. Several studies that have applied dynamic causal modeling (DCM) to fMRI data have arrived at seemingly divergent conclusions. However, these divergent results could be explained by the hypothesis that the processing route of somatosensory information changes with time. Specifically, we suggest that somatosensory stimuli are processed in parallel only during the early stage, whereas the processing is later dominated by serial processing. This hypothesis was revisited in the present study based on fMRI analyses of tactile stimuli and the application of DCM to magnetoencephalographic (MEG) data collected during sustained (260 ms) tactile stimulation. Bayesian model comparisons were used to infer the processing stream. We demonstrated that the favored processing stream changes over time. We found that the neural activity elicited in the first 100 ms following somatosensory stimuli is best explained by models that support a parallel processing route, whereas a serial processing route is subsequently favored. These results suggest that the secondary somatosensory area (SII) receives information regarding a new stimulus in parallel with the primary somatosensory area (SI), whereas later processing in the SII is dominated by the preprocessed input from the SI. PMID:28066197

  9. Neural coupling between homologous muscles during bimanual tasks: effects of visual and somatosensory feedback.

    PubMed

    Nguyen, Hoi B; Lee, Sang Wook; Harris-Love, Michelle L; Lum, Peter S

    2017-02-01

    While the effects of sensory feedback on bimanual tasks have been studied extensively at two ends of the motor control hierarchy, the cortical and behavioral levels, much less is known about how it affects the intermediate levels, including neural control of homologous muscle groups. We investigated the effects of somatosensory input on the neural coupling between homologous arm muscles during bimanual tasks. Twelve subjects performed symmetric elbow flexion/extension tasks under different types of sensory feedback. The first two types involve visual feedback, with one imposing stricter force symmetry than the other. The third incorporated somatosensory feedback via a balancing apparatus that forced the two limbs to produce equal force levels. Although the force error did not differ between feedback conditions, the somatosensory feedback significantly increased temporal coupling of bilateral force production, indicated by a high correlation between left/right force profiles (P < 0.001). More importantly, intermuscular coherence between biceps brachii muscles was significantly higher with somatosensory feedback than others (P = 0.001). Coherence values also significantly differed between tasks (flexion/extension). Notably, whereas feedback type mainly modulated coherence in the α- and γ-bands, task type only affected β-band coherence. Similar feedback effects were observed for triceps brachii muscles, but there was also a strong phase effect on the coherence values (P < 0.001) that could have diluted feedback effects. These results suggest that somatosensory feedback can significantly increase neural coupling between homologous muscles. Additionally, the between-task difference in β-band coherence may reflect different neural control strategies for the elbow flexor and extensor muscles.

  10. Understanding the role of the primary somatosensory cortex: Opportunities for rehabilitation.

    PubMed

    Borich, M R; Brodie, S M; Gray, W A; Ionta, S; Boyd, L A

    2015-12-01

    Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes.

  11. Task-specific role of ipsilateral pathways: somatosensory evoked potentials during cooperative hand movements.

    PubMed

    Schrafl-Altermatt, Miriam; Dietz, Volker

    2014-12-17

    Task-specific neural coupling during cooperative hand movements has been described in healthy volunteers, manifested by bilateral reflex electromyographic responses in forearm muscles following unilateral ulnar nerve stimulation and by task-specific activation of secondary somatosensory cortical areas (S2) in functional MRI. The aim of this study was to investigate the role of sensory input to the ipsilateral and contralateral cortex during a cooperative task. Somatosensory evoked potentials from the ulnar nerve were recorded over the ipsilateral and contralateral cortex during resting and during cooperative and noncooperative hand movements. Ipsilateral potentials with smaller amplitude were present under all conditions in almost all participants. In relation to the resting condition, the amplitudes of both the ipsilateral and the contralateral potential were reduced during the cooperative and the noncooperative tasks. Nevertheless, the reduction in amplitude was similar for the ipsilateral and the contralateral potentials in the noncooperative task, but less on the ipsilateral compared with the contralateral side during the cooperative task. The ratio of ipsilateral/contralateral somatosensory evoked potential amplitude was thus significantly larger during the cooperative task compared with the control task and the resting condition. This indicates a functional role of ipsilateral pathways connecting the cervical spinal cord with the cortex during the cooperative task. These observations favor the idea of a task-specific mediation of sensory input from both hands to the ipsilateral and contralateral hemispheres as the basis of neuronal coupling.

  12. 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

  13. 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.

  14. Interactions of acoustic and somatosensory evoked responses in a polysensory cortex of the cat.

    PubMed

    Toldi, J; Fehér, O

    1987-01-01

    Interactions of acoustic and somatosensory evoked potentials were studied in the anterior suprasylvian gyrus of the cat. The interactions showed dynamic changes and were susceptible to different kinds of influences. The interactions could be influenced by synchronous activation of the acoustic and somatosensory inputs with 2 Hz frequency, or by elevating the stimulus frequency. Interactions could be influenced by amphetamine and gamma-glutamyl-taurine, drugs known as capable of influencing the arousal level of the brain. The antagonists of amphetamine prevented this effect. Drugs acting on the cortical GABA-ergic system proved also to be decisive in the interactions of evoked potentials of different origins. In some experiments unit activity was recorded parallel with evoked potentials.

  15. 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.

  16. Vestibular-Somatosensory Convergence in Head Movement Control During Locomotion after Long-Duration Space Flight

    NASA Technical Reports Server (NTRS)

    Mulavara, Ajitkumar; Ruttley, Tara; Cohen, Helen; Peters, Brian; Miller, Chris; Brady, Rachel; Merkle, Lauren; Bloomberg, Jacob

    2010-01-01

    Exposure to the microgravity conditions of space flight induces adaptive modification in the control of vestibular-mediated reflexive head movement during locomotion after space flight. Space flight causes astronauts to be exposed to somatosensory adaptation in both the vestibular and body load-sensing (BLS) systems. The goal of these studies was to examine the contributions of vestibular and BLS-mediated somatosensory influences on head movement control during locomotion after long-duration space flight. Subjects were asked to walk on a treadmill driven at 1.8 m/s while performing a visual acuity task. Data were collected using the same testing protocol from three independent subject groups; 1) normal subjects before and after exposure to 30 minutes of 40% bodyweight unloaded treadmill walking, 2) bilateral labyrinthine deficient (LD) patients and 3) astronauts who performed the protocol before and after long duration space flight. Motion data from head and trunk segmental motion data were obtained to calculate the angular head pitch (HP) movements during walking trials while subjects performed the visual task, to estimate the contributions of vestibular reflexive mechanisms in HP movements. Results showed that exposure to unloaded locomotion caused a significant increase in HP movements, whereas in the LD patients the HP movements were significantly decreased. Astronaut subjects results showed a heterogeneous response of both increases and decreases in the amplitude of HP movement. We infer that BLS-mediated somatosensory input centrally modulates vestibular input and can adaptively modify head-movement control during locomotion. Thus, space flight may cause a central adaptation mediated by the converging vestibular and body load-sensing somatosensory systems.

  17. Modulation of excitability in human primary somatosensory and motor cortex by paired associative stimulation targeting the primary somatosensory cortex.

    PubMed

    Kriváneková, Lucia; Lu, Ming-Kuei; Bliem, Barbara; Ziemann, Ulf

    2011-10-01

    Input from primary somatosensory cortex (S1) to primary motor cortex (M1) is important for high-level motor performance, motor skill learning and motor recovery after brain lesion. This study tested the effects of manipulating S1 excitability with paired associative transcranial stimulation (S1-PAS) on M1 excitability. Given the important role of S1 in sensorimotor integration, we hypothesized that changes in S1 excitability would be directly paralleled by changes in M1 excitability. We applied two established protocols (S1-PAS(LTP) and S1-PAS(LTD) ) to the left S1 to induce long-term potentiation (LTP)-like or long-term depression (LTD)-like plasticity. S1 excitability was assessed by the early cortical components (N20-P25) of the median nerve somatosensory-evoked potential. M1 excitability was assessed by motor-evoked potential amplitude and short-interval intracortical inhibition. Effects of S1-PAS(LTP) were compared with those of a PAS(LTP) protocol targeting the left M1 (M1-PAS(LTP) ). S1-PAS(LTP) and S1-PAS(LTD) did not result in significant modifications of S1 or M1 excitability at the group level due to substantial interindividual variability. The individual S1-PAS-induced changes in S1 and M1 excitability showed no correlation. Furthermore, the individual changes in S1 and M1 excitability induced by S1-PAS(LTP) did not correlate with changes in M1 excitability induced by M1-PAS(LTP) . This demonstrates that the effects of S1-PAS in S1 are variable across individuals and, within a given individual, unrelated to those induced by S1-PAS or M1-PAS in M1. Potentially, this extends the opportunities of therapeutic PAS applications because M1-PAS 'non-responders' may well respond to S1-PAS.

  18. 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

  19. Epidural motor cortex stimulation suppresses somatosensory evoked potentials in the primary somatosensory cortex of the rat.

    PubMed

    Chiou, Ruei-Jen; Lee, Hsiao-Yun; Chang, Chen-Wei; Lin, Kuan-Hung; Kuo, Chung-Chih

    2012-06-29

    Motor cortex stimulation (MCS) is a promising clinical procedure to help alleviate chronic pain. Animal models demonstrated that MCS is effective in lessening nocifensive behaviors. The present study explored the effects of MCS on cortical somatosensory evoked potentials (SEPs) recorded at the primary somatosensory cortex (SI) of the rat. SEPs were evoked by electrical stimulation applied to the contralateral forepaws. Effects of different intensities, frequencies, and durations of MCS were tested. MCS at ≥2V suppressed SEPs of the ipsilateral SI. Suppression lasted 120 min at an intensity of 5 V. The optimal frequency was 50 Hz, and the duration was 30s. In contrast, MCS did not affect SEPs recorded on the contralateral SI. Cortical stimulation out of the motor cortex did not induce a decrease in the ipsilateral SEPs. We also investigated involvement of the endogenous opioid system in this inhibition of SEPs induced by MCS. The opioid antagonist, naloxone (0.5 mg/kg), was administered 30 min before MCS. Application of naloxone completely prevented the inhibitory effect of MCS on ipsilateral SEPs. These results demonstrate that MCS blocked the transmission of somatosensory information to the primary somatosensory cortex, and this interference was mediated by the endogenous opioid system. This inhibitory effect on sensory transmission induced by MCS may reflect its antinociceptive effect.

  20. Coding perceptual discrimination in the somatosensory thalamus

    PubMed Central

    Camarillo, Liliana; Luna, Rogelio; Nácher, Verónica; Romo, Ranulfo

    2012-01-01

    The sensory thalamus is classically viewed as a relay station of sensory information to cortex, but recent studies suggest that it is sensitive to cognitive demands. There are, however, few experiments designed to test whether this is so. We addressed this problem by analyzing the responses of single neurons recorded in the somatosensory thalamus while trained monkeys reported a decision based on the comparison of two mechanical vibration frequencies applied sequentially to one fingertip. In this task, monkeys must hold the first stimulus frequency (f1) in working memory and compare it to the current sensory stimulus (f2) and must postpone the decision report until a cue triggers the decision motor report, i.e., whether f2 > f1 or f2 < f1. We found that thalamic somatosensory neurons encoded the stimulus frequency either in their periodicity and firing-rate responses, but only during the stimulus periods and not during the working memory and decision components of this task. Furthermore, correlation analysis between behavior and stimulus coding showed that only the firing rate modulations accounted for the overall psychophysical performance. However, these responses did not predict the animal’s decision reports on individual trials. Moreover, the sensitivity to changes in stimulus frequency was similar when the monkeys performed the vibrotactile discrimination task and when they were not required to report discrimination. These results suggest that the somatosensory thalamus behaves as a relay station of sensory information to the cortex and that it is insensitive to the cognitive demands of the task used here. PMID:23213243

  1. Beyond the Peak - Tactile Temporal Discrimination Does Not Correlate with Individual Peak Frequencies in Somatosensory Cortex.

    PubMed

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

    2017-01-01

    The human sensory systems constantly receive input from different stimuli. Whether these stimuli are integrated into a coherent percept or segregated and perceived as separate events, is critically determined by the temporal distance of the stimuli. This temporal distance has prompted the concept of temporal integration windows or perceptual cycles. Although this concept has gained considerable support, the neuronal correlates are still discussed. Studies suggested that neuronal oscillations might provide a neuronal basis for such perceptual cycles, i.e., the cycle lengths of alpha oscillations in visual cortex and beta oscillations in somatosensory cortex might determine the length of perceptual cycles. Specifically, recent studies reported that the peak frequency (the frequency with the highest spectral power) of alpha oscillations in visual cortex correlates with subjects' ability to discriminate two visual stimuli. In the present study, we investigated whether peak frequencies in somatosensory cortex might serve as the correlate of perceptual cycles in tactile discrimination. Despite several different approaches, we were unable to find a significant correlation between individual peak frequencies in the alpha- and beta-band and individual discrimination abilities. In addition, analysis of Bayes factor provided evidence that peak frequencies and discrimination thresholds are unrelated. The results suggest that perceptual cycles in the somatosensory domain are not necessarily to be found in the peak frequency, but in other frequencies. We argue that studies based solely on analysis of peak frequencies might thus miss relevant information.

  2. Effect of muscle contraction strength on gating of somatosensory magnetic fields.

    PubMed

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

    2016-11-01

    Afferent somatosensory information is modulated before the afferent input arrives at the primary somatosensory cortex during voluntary movement. The aim of the present study was to clarify the effect of muscular contraction strength on somatosensory evoked fields (SEFs) during voluntary movement. In addition, we examined the differences in gating between innervated and non-innervated muscle during contraction. We investigated the changes in gating effect by muscular contraction strength and innervated and non-innervated muscles in human using 306-channel magnetoencephalography. SEFs were recorded following the right median nerve stimulation in a resting condition and during isometric muscular contractions from 10 % electromyographic activity (EMG), 20 and 30 % EMG of the right extensor indicis muscle and abductor pollicis brevis muscle. Our results showed that the equivalent current dipole (ECD) strength for P35m decreased with increasing strength of muscular contraction of the right abductor pollicis brevis muscle. However, changes were observed only at 30 % EMG contraction level of the right extensor indicis muscle, which was not innervated by the median nerve. There were no significant changes in the peak latencies and ECD locations of each component in all conditions. The ECD strength did not differ significantly for N20m and P60m regardless of the strength of muscular contraction and innervation. Therefore, we suggest that the gating of SEF waveforms following peripheral nerve stimulation was affected by the strength of muscular contraction and innervation of the contracting muscle.

  3. Effects of aerobic exercise under different thermal conditions on human somatosensory processing.

    PubMed

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

    2016-10-01

    The present study aimed to investigate the effects of aerobic exercise on human somatosensory processing recorded by somatosensory evoked potentials (SEPs) under temperate [TEMP, 20°C and 40% relative humidity (RH)] and hot (HOT, 35°C and 30% RH) environments. Fifteen healthy subjects performed 4 × 15-min bouts of a moderate cycling exercise [mean power output: 156.5 ± 7.7 (SE) W], with a 10-min rest period and received a posterior tibial nerve stimulation at the left ankle before and after each exercise bout; SEPs were recorded in five sessions; 1st (pre), 2nd (post-1st exercise bout), 3rd (post-2nd exercise bout), 4th (post-3rd exercise bout), and 5th (post-4th exercise bout). The peak latencies and amplitudes of the P37, N50, P60, and N70 components at Cz were evaluated. The latencies of P37, N50, P60, and N70 were significantly shorter with the repetition of aerobic exercise, and these shortened latencies were significantly greater in the HOT condition than in the TEMP condition (P37: 3rd, P < 0.05, and 5th, P < 0.01; P60: 4th, P < 0.05, and 5th, P < 0.01; N70: 4th, P < 0.05, and 5th, P < 0.001). No significant differences were observed in the amplitudes of any SEP component under either thermal condition. These results suggest that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and aerobic exercise did not alter the strength of neural activity in cortical somatosensory processing.

  4. Subthalamic nucleus stimulation and somatosensory temporal discrimination in Parkinson's disease.

    PubMed

    Conte, Antonella; Modugno, Nicola; Lena, Francesco; Dispenza, Sabrina; Gandolfi, Barbara; Iezzi, Ennio; Fabbrini, Giovanni; Berardelli, Alfredo

    2010-09-01

    Whereas numerous studies document the effects of dopamine medication and deep brain stimulation on motor function in patients with Parkinson's disease, few have investigated deep brain stimulation-induced changes in sensory functions. In this study of 13 patients with Parkinson's disease, we tested the effects of deep brain stimulation on the somatosensory temporal discrimination threshold. To investigate whether deep brain stimulation and dopaminergic medication induce similar changes in somatosensory discrimination, somatosensory temporal discrimination threshold values were acquired under four experimental conditions: (i) medication ON/deep brain stimulation on; (ii) medication ON/deep brain stimulation off; (iii) medication OFF/deep brain stimulation on; and (iv) medication OFF/deep brain stimulation off. Patients also underwent clinical and neuropsychological evaluations during each experimental session. Somatosensory temporal discrimination threshold values obtained in patients were compared with 13 age-matched healthy subjects. Somatosensory temporal discrimination threshold values were significantly higher in patients than in healthy subjects. In patients, somatosensory temporal discrimination threshold values were significantly lower when patients were studied in medication ON than in medication OFF conditions. Somatosensory temporal discrimination threshold values differed significantly between deep brain stimulation on and deep brain stimulation off conditions only when the patients were studied in the medication ON condition and were higher in the deep brain stimulation on/medication ON than in the deep brain stimulation off/medication ON condition. Dopamine but not subthalamic nucleus deep brain stimulation restores the altered somatosensory temporal discrimination in patients with Parkinson's disease. Deep brain stimulation degrades somatosensory temporal discrimination by modifying central somatosensory processing whereas dopamine restores the

  5. Short-term expansion of receptive fields in rat primary somatosensory cortex after hindpaw digit denervation.

    PubMed

    Byrne, J A; Calford, M B

    1991-11-29

    The immediate effect of changing the driving cutaneous input to locations within primary somatosensory cortex (SI) was examined by denervating one or more digits of the rat hindpaw by amputation or local anesthesia. When all or part of a receptive field of a cluster of neurons was denervated, it was found that the cortical location recorded from gained responsiveness to cutaneous stimulation of hindpaw areas bordering the denervated region. In 22 of the 29 animals studied this expansion took place within 5 min of the denervation.

  6. Circadian rhythmicity of synapses in mouse somatosensory cortex.

    PubMed

    Jasinska, Malgorzata; Grzegorczyk, Anna; Woznicka, Olga; Jasek, Ewa; Kossut, Malgorzata; Barbacka-Surowiak, Grazyna; Litwin, Jan A; Pyza, Elzbieta

    2015-10-01

    The circadian rhythmicity displayed by motor behavior of mice: activity at night and rest during the day; and the associated changes in the sensory input are reflected by cyclic synaptic plasticity in the whisker representations located in the somatosensory (barrel) cortex. It was not clear whether diurnal rhythmic changes in synapse density previously observed in the barrel cortex resulted from changes in the activity of the animals, from daily light/dark (LD) rhythm or are driven by an endogenous clock. These changes were investigated in the barrel cortex of C57BL/6 mouse strain kept under LD 12 : 12 h conditions and in constant darkness (DD). Stereological analysis of serial electron microscopic sections was used to assess numerical density of synapses. In mice kept under LD conditions, the total density of synapses and the density of excitatory synapses located on dendritic spines was higher during the light period (rest phase). In contrast, the density of inhibitory synapses located on dendritic spines increased during the dark period (activity phase). Under DD conditions, the upregulation of the inhibitory synapses during the activity phase was retained, but the cyclic changes in the density of excitatory synapses were not observed. The results show that the circadian plasticity concerns only synapses located on spines (and not those on dendritic shafts), and that excitatory and inhibitory synapses are differently regulated during the 24 h cycle: the excitatory synapses are influenced by light, whilst the inhibitory synapses are driven by the endogenous circadian clock.

  7. 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

  8. 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.

  9. Early determination of somatosensory cortex in the human brain.

    PubMed

    Juenger, Hendrik; de Haan, Bianca; Krägeloh-Mann, Ingeborg; Staudt, Martin; Karnath, Hans-Otto

    2011-08-01

    The developing brain possesses a high potential for neuroplasticity. Yet, this remarkable potential of (re-)organization is not a general principle. It seems to vary among different functional systems. Here, we show that distinct brain structures involved in somatosensory processing are already prenatally determined so that a pre- or perinatally acquired (congenital) brain damage of such structures results in a persistent somatosensory deficit. Eleven patients with hemiparesis due to congenital cortico-subcortical unilateral stroke who showed versus not showed a somatosensory deficit were contrasted with magnetic resonance imaging lesion-behavior mapping. The brain areas which were typically damaged in patients with a somatosensory deficit but typically spared in patients without a somatosensory deficit were located in the primary and secondary somatosensory cortex (S1, S2) as well as the inferior parietal cortex directly neighboring S1 and S2. The results argue for an early functional determination of primary and secondary somatosensory cortex, without substantial capacities for (re-)organization. They demonstrate that cortical damage of these areas cannot be compensated by shifting the functional representation to undamaged parts of the cortex.

  10. Primary somatosensory cortex hand representation dynamically modulated by motor output.

    PubMed

    McGeoch, Paul D; Brang, David; Huang, Mingxiong; Ramachandran, V S

    2015-02-01

    The brain's primary motor and primary somatosensory cortices are generally viewed as functionally distinct entities. Here we show by means of magnetoencephalography with a phantom-limb patient, that movement of the phantom hand leads to a change in the response of the primary somatosensory cortex to tactile stimulation. This change correlates with the described conscious perception and suggests a greater degree of functional unification between the primary motor and somatosensory cortices than is currently realized. We suggest that this may reflect the evolution of this part of the human brain, which is thought to have occurred from an undifferentiated sensorimotor cortex.

  11. THE INFLUENCE OF VIBRISSAL SOMATOSENSORY PROCESSING IN RAT SUPERIOR COLLICULUS ON PREY CAPTURE

    PubMed Central

    FAVARO, P. D. N.; GOUVÊA, T. S.; DE OLIVEIRA, S. R.; VAUTRELLE, N.; REDGRAVE, P.; COMOLI, E.

    2011-01-01

    The lateral part of intermediate layer of superior colliculus (SCl) is a critical substrate for successful predation by rats. Hunting-evoked expression of the activity marker Fos is concentrated in SCl while prey capture in rats with NMDA lesions in SCl is impaired. Particularly affected are rapid orienting and stereotyped sequences of actions associated with predation of fast moving prey. Such deficits are consistent with the view that the deep layers of SC are important for sensory guidance of movement. Although much of the relevant evidence involves visual control of movement, less is known about movement guidance by somatosensory input from vibrissae. Indeed, our impression is that prey contact with whiskers is a likely stimulus to trigger predation. Moreover, SCl receives whisker and orofacial somatosensory information directly from trigeminal complex, and indirectly from zona incerta, parvicelular reticular formation and somatosensory barrel cortex. To better understand sensory guidance of predation by vibrissal information we investigated prey capture by rats after whisker removal and the role of superior colliculus (SC) by comparing Fos expression after hunting with and without whiskers. Rats were allowed to hunt cockroaches, after which their whiskers were removed. Two days later they were allowed to hunt cockroaches again. Without whiskers the rats were less able to retain the cockroaches after capture and less able to pursue them in the event of the cockroach escaping. The predatory behaviour of rats with re-grown whiskers returned to normal. In parallel, Fos expression in SCl induced by predation was significantly reduced in whiskerless animals. We conclude that whiskers contribute to the efficiency of rat prey capture and that the loss of vibrissal input to SCl, as reflected by reduced Fos expression, could play a critical role in predatory deficits of whiskerless rats. PMID:21163336

  12. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject.

    PubMed

    Ioannides, Andreas A; Liu, Lichan; Poghosyan, Vahe; Saridis, George A; Gjedde, Albert; Ptito, Maurice; Kupers, Ron

    2013-01-01

    Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG) data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1) and motor (M1) cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45-70 Hz activity at latencies of 20-50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA) 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong, and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI) revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occurred in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

  13. Inhibitory modulation of cat somatosensory cortex: a pharmacological study.

    PubMed

    Brailowsky, S; Knight, R T

    1984-11-26

    In anesthetized preparations, GABA and taurine produced rapid, reversible inhibition of the negative component (N20) of the primary somatosensory evoked potential (SEP) without effect on the earlier positivity (P11). This effect was also produced by low doses of 4-aminopyridine. Neither bicuculline or picrotoxin antagonized these drug effects. A predominance of type B GABA receptors in the superficial layers of the somatosensory cortex is proposed.

  14. 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.

  15. 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

  16. 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

  17. Shared somatosensory and motor functions in musicians

    PubMed Central

    Hosoda, Moe; Furuya, Shinichi

    2016-01-01

    Skilled individuals are characterized by fine-tuned perceptual and motor functions. Here, we tested the idea that the sensory and motor functions of highly-trained individuals are coupled. We assessed the relationships among multifaceted somatosensory and motor functions of expert pianists. The results demonstrated a positive covariation between the acuity of weight discrimination and the precision of force control during piano keystrokes among the pianists but not among the non-musicians. However, neither the age of starting musical training nor the total amount of life-long piano practice was correlated with these sensory-motor functions in the pianists. Furthermore, a difference between the pianists and non-musicians was absent for the weight discrimination acuity but present for precise force control during keystrokes. The results suggest that individuals with innately superior sensory function had finer motor control only in a case of having undergone musical training. Intriguingly, the tactile spatial acuity of the fingertip was superior in the pianists compared with the non-musicians but was not correlated with any functions representing fine motor control among the pianists. The findings implicate the presence of two distinct mechanisms of sensorimotor learning elicited by musical training, which occur either independently in individual sensorimotor modalities or through interacting between modalities. PMID:27886250

  18. Frequency Specific Modulation of Human Somatosensory Cortex

    PubMed Central

    Feurra, Matteo; Paulus, Walter; Walsh, Vincent; Kanai, Ryota

    2011-01-01

    Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One-way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS) over the primary somatosensory cortex (SI) could elicit tactile sensations in humans in a frequency-dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10–14 Hz) and high gamma (52–70 Hz) frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16–20 Hz) stimulation. These findings highlight the frequency dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous electroencephalography/magnetoencephalography studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities. PMID:21713181

  19. Amplified somatosensory and visual cortical projections to a core auditory area, the anterior auditory field, following early- and late-onset deafness.

    PubMed

    Wong, Carmen; Chabot, Nicole; Kok, Melanie A; Lomber, Stephen G

    2015-09-01

    Cross-modal reorganization following the loss of input from a sensory modality can recruit sensory-deprived cortical areas to process information from the remaining senses. Specifically, in early-deaf cats, the anterior auditory field (AAF) is unresponsive to auditory stimuli but can be activated by somatosensory and visual stimuli. Similarly, AAF neurons respond to tactile input in adult-deafened animals. To examine anatomical changes that may underlie this functional adaptation following early or late deafness, afferent projections to AAF were examined in hearing cats, and cats with early- or adult-onset deafness. Unilateral deposits of biotinylated dextran amine were made in AAF to retrogradely label cortical and thalamic afferents to AAF. In early-deaf cats, ipsilateral neuronal labeling in visual and somatosensory cortices increased by 329% and 101%, respectively. The largest increases arose from the anterior ectosylvian visual area and the anterolateral lateral suprasylvian visual area, as well as somatosensory areas S2 and S4. Consequently, labeling in auditory areas was reduced by 36%. The age of deafness onset appeared to influence afferent connectivity, with less marked differences observed in late-deaf cats. Profound changes to visual and somatosensory afferent connectivity following deafness may reflect corticocortical rewiring affording acoustically deprived AAF with cross-modal functionality.

  20. Neuronal activity controls the development of interneurons in the somatosensory cortex

    PubMed Central

    Babij, Rachel

    2017-01-01

    BACKGROUND Neuronal activity in cortical areas regulates neurodevelopment by interacting with defined genetic programs to shape the mature central nervous system. Electrical activity is conveyed to sensory cortical areas via intracortical and thalamocortical neurons, and includes oscillatory patterns that have been measured across cortical regions. OBJECTIVE In this work, we review the most recent findings about how electrical activity shapes the developmental assembly of functional circuitry in the somatosensory cortex, with an emphasis on interneuron maturation and integration. We include studies on the effect of various neurotransmitters and on the influence of thalamocortical afferent activity on circuit development. We additionally reviewed studies describing network activity patterns. METHODS We conducted an extensive literature search using both the PubMed and Google Scholar search engines. The following keywords were used in various iterations: “interneuron”, “somatosensory”, “development”, “activity”, “network patterns”, “thalamocortical”, “NMDA receptor”, “plasticity”. We additionally selected papers known to us from past reading, and those recommended to us by reviewers and members of our lab. RESULTS We reviewed a total of 132 articles that focused on the role of activity in interneuronal migration, maturation, and circuit development, as well as the source of electrical inputs and patterns of cortical activity in the somatosensory cortex. 79 of these papers included in this timely review were written between 2007 and 2016. CONCLUSIONS Neuronal activity shapes the developmental assembly of functional circuitry in the somatosensory cortical interneurons. This activity impacts nearly every aspect of development and acquisition of mature neuronal characteristics, and may contribute to changing phenotypes, altered transmitter expression, and plasticity in the adult. Progressively changing oscillatory network patterns

  1. Interhemispheric plasticity protects the deafferented somatosensory cortex from functional takeover after nerve injury.

    PubMed

    Yu, Xin; Koretsky, Alan P

    2014-11-01

    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.

  2. 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

  3. Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys.

    PubMed

    Qi, Hui-Xin; Wang, Feng; Liao, Chia-Chi; Friedman, Robert M; Tang, Chaohui; Kaas, Jon H; Avison, Malcolm J

    2016-11-15

    After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution cerebral blood volume-based functional magnetic resonance imaging (CBV-fMRI) mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6weeks after a mid-cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with individual differences in damage to and recovery of DC and spinocuneate pathways, and possibly the potentiation of spinothalamic pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on

  4. The Development of Nociceptive Network Activity in the Somatosensory Cortex of Freely Moving Rat Pups

    PubMed Central

    Chang, P.; Fabrizi, L.; Olhede, S.; Fitzgerald, M.

    2016-01-01

    Cortical perception of noxious stimulation is an essential component of pain experience but it is not known how cortical nociceptive activity emerges during brain development. Here we use continuous telemetric electrocorticogram (ECoG) recording from the primary somatosensory cortex (S1) of awake active rat pups to map functional nociceptive processing in the developing brain over the first 4 weeks of life. Cross-sectional and longitudinal recordings show that baseline S1 ECoG energy increases steadily with age, with a distinctive beta component replaced by a distinctive theta component in week 3. Event-related potentials were evoked by brief noxious hindpaw skin stimulation at all ages tested, confirming the presence of functional nociceptive spinothalamic inputs in S1. However, hindpaw incision, which increases pain sensitivity at all ages, did not increase S1 ECoG energy until week 3. A significant increase in gamma (20–50 Hz) energy occurred in the presence of skin incision at week 3 accompanied by a longer-lasting increase in theta (4–8 Hz) energy at week 4. Continuous ECoG recording demonstrates specific postnatal functional stages in the maturation of S1 cortical nociception. Somatosensory cortical coding of an ongoing pain “state” in awake rat pups becomes apparent between 2 and 4 weeks of age. PMID:27797835

  5. Visual-somatosensory integration in aging: does stimulus location really matter?

    PubMed

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

    2014-05-01

    Individuals are constantly bombarded by sensory stimuli across multiple modalities that must be integrated efficiently. Multisensory integration (MSI) is said to be governed by stimulus properties including space, time, and magnitude. While there is a paucity of research detailing MSI in aging, we have demonstrated that older adults reveal the greatest reaction time (RT) benefit when presented with simultaneous visual-somatosensory (VS) stimuli. To our knowledge, the differential RT benefit of visual and somatosensory stimuli presented within and across spatial hemifields has not been investigated in aging. Eighteen older adults (Mean = 74 years; 11 female), who were determined to be non-demented and without medical or psychiatric conditions that may affect their performance, participated in this study. Participants received eight randomly presented stimulus conditions (four unisensory and four multisensory) and were instructed to make speeded foot-pedal responses as soon as they detected any stimulation, regardless of stimulus type and location of unisensory inputs. Results from a linear mixed effect model, adjusted for speed of processing and other covariates, revealed that RTs to all multisensory pairings were significantly faster than those elicited to averaged constituent unisensory conditions (p < 0.01). Similarly, race model violation did not differ based on unisensory spatial location (p = 0.41). In summary, older adults demonstrate significant VS multisensory RT effects to stimuli both within and across spatial hemifields.

  6. Dependence of the negative BOLD response on somatosensory stimulus intensity.

    PubMed

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

    2010-10-15

    The primary somatosensory cortex (SI) has been shown to encode the intensity of a stimulus applied to the contralateral side of the body. Recent studies have demonstrated that ipsilateral SI is also involved in the processing of somatosensory information. In this study, we investigated the dependence of the negative BOLD response in ipsilateral SI on the intensity of somatosensory stimulation. Functional MRI was performed in 12 healthy subjects during electrical median nerve stimulation at four different intensities. A monotonic relationship between stimulus intensity and the strength of the negative BOLD response in ipsilateral SI was found. Additionally, a psychophysiological experiment revealed tight coupling between the stimulus intensity applied to one hand and increased perceptual threshold of the other hand. These findings indicate a stimulus intensity-dependent inhibition of ipsilateral SI.

  7. Impairing somatosensory working memory using rTMS.

    PubMed

    Auksztulewicz, Ryszard; Spitzer, Bernhard; Goltz, Dominique; Blankenburg, Felix

    2011-09-01

    Numerous studies in animals and humans have related central aspects of somatosensory working memory function to neural activity in the inferior frontal gyrus (IFG). However, as previous studies have almost exclusively used correlational analyses, the question whether sustained neural activity in the IFG is causally involved in successful maintenance of somatosensory information remains unanswered. We used an online repetitive transcranial magnetic stimulation (rTMS) protocol to disrupt neuronal activity in the IFG while participants were maintaining tactile information throughout the delay for later comparison against a probe stimulus. rTMS impaired participants' performance in the working memory task, but not in a physically matched perceptual control task. Targeting the IFG in either hemisphere led to comparable working memory impairment. Our results show that the neural activity in the IFG plays a causal role in successful maintenance of somatosensory information.

  8. Beyond the Peak – Tactile Temporal Discrimination Does Not Correlate with Individual Peak Frequencies in Somatosensory Cortex

    PubMed Central

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

    2017-01-01

    The human sensory systems constantly receive input from different stimuli. Whether these stimuli are integrated into a coherent percept or segregated and perceived as separate events, is critically determined by the temporal distance of the stimuli. This temporal distance has prompted the concept of temporal integration windows or perceptual cycles. Although this concept has gained considerable support, the neuronal correlates are still discussed. Studies suggested that neuronal oscillations might provide a neuronal basis for such perceptual cycles, i.e., the cycle lengths of alpha oscillations in visual cortex and beta oscillations in somatosensory cortex might determine the length of perceptual cycles. Specifically, recent studies reported that the peak frequency (the frequency with the highest spectral power) of alpha oscillations in visual cortex correlates with subjects’ ability to discriminate two visual stimuli. In the present study, we investigated whether peak frequencies in somatosensory cortex might serve as the correlate of perceptual cycles in tactile discrimination. Despite several different approaches, we were unable to find a significant correlation between individual peak frequencies in the alpha- and beta-band and individual discrimination abilities. In addition, analysis of Bayes factor provided evidence that peak frequencies and discrimination thresholds are unrelated. The results suggest that perceptual cycles in the somatosensory domain are not necessarily to be found in the peak frequency, but in other frequencies. We argue that studies based solely on analysis of peak frequencies might thus miss relevant information. PMID:28382013

  9. Do patients with chronic patellar tendinopathy have an altered somatosensory profile? A Quantitative Sensory Testing (QST) study.

    PubMed

    van Wilgen, C P; Konopka, K H; Keizer, D; Zwerver, J; Dekker, R

    2013-03-01

    The prevalence of tendinopathies in sports is high. The etiology and pain mechanisms of tendinopathies are not completely understood. Currently, little is known whether, or to which degree, somatosensory changes within the nervous system may contribute to the pain in tendinopathies. We conducted a patient controlled study in which we used the standardized QST protocol developed by the German Research Network on Neuropathic Pain. This protocol consists of seven different tests that measures 13 somatosensory parameters and can be seen as the gold standard to measure somatosensory function. Twelve athletes with clinically diagnosed chronic patellar tendinopathy (PT) mean duration 30 months (range 6-120) and 20 controls were included in the study. In two of the 13 QST parameters namely Mechanical Pain Threshold (P < 0.05) and Vibration Disappearance Threshold (P < 0.5) injured athletes were significantly more sensitive for the applied stimuli. None of the athletes had signs of Dynamic Mechanical Allodynia. Reduced mechanical pain thresholds or pinprick allodynia reflects the involvement of central sensitization upon the myelinated (Aδ-fibre) nociceptive input. From this explorative study, we conclude that sensitization may play a prominent role in the pain during and after sports activity in patella tendinopathy patients.

  10. Auditory-Somatosensory Temporal Sensitivity Improves When the Somatosensory Event Is Caused by Voluntary Body Movement

    PubMed Central

    Kitagawa, Norimichi; Kato, Masaharu; Kashino, Makio

    2016-01-01

    When we actively interact with the environment, it is crucial that we perceive a precise temporal relationship between our own actions and sensory effects to guide our body movements. Thus, we hypothesized that voluntary movements improve perceptual sensitivity to the temporal disparity between auditory and movement-related somatosensory events compared to when they are delivered passively to sensory receptors. In the voluntary condition, participants voluntarily tapped a button, and a noise burst was presented at various onset asynchronies relative to the button press. The participants made either “sound-first” or “touch-first” responses. We found that the performance of temporal order judgment (TOJ) in the voluntary condition (as indexed by the just noticeable difference (JND)) was significantly better (M = 42.5 ms ± 3.8 SEM) than that when their finger was passively stimulated (passive condition: M = 66.8 ms ± 6.3 SEM). We further examined whether the performance improvement with voluntary action can be attributed to the prediction of the timing of the stimulation from sensory cues (sensory-based prediction), kinesthetic cues contained in voluntary action, and/or to the prediction of stimulation timing from the efference copy of the motor command (motor-based prediction). When three noise bursts were presented before the target burst with regular intervals (predictable condition) and when the participant’s finger was moved passively to press the button (involuntary condition), the TOJ performance was not improved from that in the passive condition. These results suggest that the improvement in sensitivity to temporal disparity between somatosensory and auditory events caused by the voluntary action cannot be attributed to sensory-based prediction and kinesthetic cues. Rather, the prediction from the efference copy of the motor command would be crucial for improving the temporal sensitivity. PMID:28018189

  11. Somatotopic direct projections from orofacial areas of secondary somatosensory cortex to trigeminal sensory nuclear complex in rats.

    PubMed

    Haque, T; Akhter, F; Kato, T; Sato, F; Takeda, R; Higashiyama, K; Moritani, M; Bae, Y-C; Sessle, B J; Yoshida, A

    2012-09-06

    Little is known about the projections from the orofacial areas of the secondary somatosensory cortex (S2) to the pons and medulla including the second-order somatosensory neuron pools. To address this in rats, we first examined the distribution of S2 neurons projecting to the trigeminal principal nucleus (Vp) or oral subnucleus (Vo) of the trigeminal sensory nuclear complex (TSNC) after injections of a retrograde tracer, Fluorogold (FG), into five regions in the Vp/Vo which were responsive to stimulation of trigeminal nerves innervating the orofacial tissues. A large number of FG-labeled neurons were found with a somatotopic arrangement in the dorsal areas of S2 (orofacial S2 area). This somatotopic arrangement in the orofacial S2 area was shown to closely match that of the orofacial afferent inputs by recording cortical surface potentials evoked by stimulation of the trigeminal nerves. We then examined the morphology of descending projections from these electrophysiologically defined areas of the orofacial S2 to the pons and medulla after injections of an anterograde tracer, biotinylated dextranamine (BDA), into the areas. A large number of BDA-labeled axon fibers and terminals were seen only in some of the second-order somatosensory neuron pools, most notably in the contralateral TSNC, although the labeled terminals were not seen in certain rostrocaudal levels of the contralateral TSNC including the rostrocaudal middle level of the trigeminal interpolar subnucleus. The projections to the TSNC showed somatotopic arrangements in dorsoventral, superficial-deep and rostrocaudal directions. The somatotopic arrangements in the Vp/Vo closely matched those of the electrophysiologically defined central projection sites of the orofacial trigeminal afferents in the TSNC. The present results suggest that the orofacial S2 projects selectively to certain rostrocaudal levels of the contralateral TSNC, and the projections may allow the orofacial S2 to accurately modulate

  12. Intrinsic Signal Imaging of Deprivation-Induced Contraction of Whisker Representations in Rat Somatosensory Cortex

    PubMed Central

    Drew, Patrick J.

    2009-01-01

    In classical sensory cortical map plasticity, the representation of deprived or underused inputs contracts within cortical sensory maps, whereas spared inputs expand. Expansion of spared inputs occurs preferentially into nearby cortical columns representing temporally correlated spared inputs, suggesting that expansion involves correlation-based learning rules at cross-columnar synapses. It is unknown whether deprived representations contract in a similar anisotropic manner, which would implicate similar learning rules and sites of plasticity. We briefly deprived D-row whiskers in 20-day-old rats, so that each deprived whisker had deprived (D-row) and spared (C- and E-row) neighbors. Intrinsic signal optical imaging revealed that D-row deprivation weakened and contracted the functional representation of deprived D-row whiskers in L2/3 of somatosensory (S1) cortex. Spared whisker representations did not strengthen or expand, indicating that D-row deprivation selectively engages the depression component of map plasticity. Contraction of deprived whisker representations was spatially uniform, with equal withdrawal from spared and deprived neighbors. Single-unit electrophysiological recordings confirmed these results, and showed substantial weakening of responses to deprived whiskers in layer 2/3 of S1, and modest weakening in L4. The observed isotropic contraction of deprived whisker representations during D-row deprivation is consistent with plasticity at intracolumnar, rather than cross-columnar, synapses. PMID:18515797

  13. Somatosensory amplification and its relationship to somatosensory, auditory, and visual evoked and event-related potentials (P300).

    PubMed

    Nakao, Mutsuhiro; Barsky, Arthur J; Nishikitani, Mariko; Yano, Eiji; Murata, Katsuyuki

    2007-03-26

    Somatosensory amplification refers to the tendency to experience benign and ambiguous somatic sensation as intense, noxious, and disturbing. The construct is helpful in assessing the perceptual style of a variety of somatizing conditions, but there is no human study clarifying the effects of neurological function on somatosensory amplification. The present study examines the relationship between somatosensory amplification and different types of evoked potentials. In 33 healthy volunteers (mean age 24 years, 18 men), latencies and amplitudes were recorded using the following parameters: short-latency somatosensory, brainstem-auditory, and visual evoked potentials (SSEP, BAEP, and VEP, respectively) and auditory event-related potentials (ERP). All subjects completed questionnaires for the Somatosensory Amplification Scale (SSAS), 20-item Toronto Alexithymia Scale (TAS-20), and Profile of Mood State (POMS). The SSAS scores were significantly associated with the P200 latency (p=0.020) and P300 amplitude of ERP (p=0.041), controlling for the significant effect of the TAS and POMS depression and tension-anxiety scales. The SSEP, BAEP, and VEP latencies or amplitudes were not statistically significant (all p>0.05). When the subjects were divided into high and low SSAS groups based on the median of the SSAS scores, the P300 amplitude of ERP significantly discriminated the two groups (p=0.023) by multiple logistic regression analysis. Although the findings should be viewed as preliminary because of the small sample size, somatosensory amplification appears to reflect some aspects of long-latency cognitive processing rather than short-latency interceptive sensitivity from the viewpoint of encephalography.

  14. 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.

  15. An embedded four-channel receive-only RF coil array for fMRI experiments of the somatosensory pathway in conscious awake marmosets.

    PubMed

    Papoti, Daniel; Yen, Cecil Chern-Chyi; Mackel, Julie B; Merkle, Hellmut; Silva, Afonso C

    2013-11-01

    fMRI has established itself as the main research tool in neuroscience and brain cognitive research. The common marmoset (Callithrix jacchus) is a non-human primate model of increasing interest in biomedical research. However, commercial MRI coils for marmosets are not generally available. The present work describes the design and construction of a four-channel receive-only surface RF coil array with excellent signal-to-noise ratio (SNR) specifically optimized for fMRI experiments in awake marmosets in response to somatosensory stimulation. The array was designed as part of a helmet-based head restraint system used to prevent motion during the scans. High SNR was obtained by building the coil array using a thin and flexible substrate glued to the inner surface of the restraint helmet, so as to minimize the distance between the array elements and the somatosensory cortex. Decoupling between coil elements was achieved by partial geometrical overlapping and by connecting them to home-built low-input-impedance preamplifiers. In vivo images show excellent coverage of the brain cortical surface with high sensitivity near the somatosensory cortex. Embedding the coil elements within the restraint helmet allowed fMRI data in response to somatosensory stimulation to be collected with high sensitivity and reproducibility in conscious, awake marmosets.

  16. Discriminability of Single and Multichannel Intracortical Microstimulation within Somatosensory Cortex.

    PubMed

    Overstreet, Cynthia K; Hellman, Randall B; Ponce Wong, Ruben D; Santos, Veronica J; Helms Tillery, Stephen I

    2016-01-01

    The addition of tactile and proprioceptive feedback to neuroprosthetic limbs is expected to significantly improve the control of these devices. Intracortical microstimulation (ICMS) of somatosensory cortex is a promising method of delivering this sensory feedback. To date, the main focus of somatosensory ICMS studies has been to deliver discriminable signals, corresponding to varying intensity, to a single location in cortex. However, multiple independent and simultaneous streams of sensory information will need to be encoded by ICMS to provide functionally relevant feedback for a neuroprosthetic limb (e.g., encoding contact events and pressure on multiple digits). In this study, we evaluated the ability of an awake, behaving non-human primate (Macaca mulatta) to discriminate ICMS stimuli delivered on multiple electrodes spaced within somatosensory cortex. We delivered serial stimulation on single electrodes to evaluate the discriminability of sensations corresponding to ICMS of distinct cortical locations. Additionally, we delivered trains of multichannel stimulation, derived from a tactile sensor, synchronously across multiple electrodes. Our results indicate that discrimination of multiple ICMS stimuli is a challenging task, but that discriminable sensory percepts can be elicited by both single and multichannel ICMS on electrodes spaced within somatosensory cortex.

  17. Discriminability of Single and Multichannel Intracortical Microstimulation within Somatosensory Cortex

    PubMed Central

    Overstreet, Cynthia K.; Hellman, Randall B.; Ponce Wong, Ruben D.; Santos, Veronica J.; Helms Tillery, Stephen I.

    2016-01-01

    The addition of tactile and proprioceptive feedback to neuroprosthetic limbs is expected to significantly improve the control of these devices. Intracortical microstimulation (ICMS) of somatosensory cortex is a promising method of delivering this sensory feedback. To date, the main focus of somatosensory ICMS studies has been to deliver discriminable signals, corresponding to varying intensity, to a single location in cortex. However, multiple independent and simultaneous streams of sensory information will need to be encoded by ICMS to provide functionally relevant feedback for a neuroprosthetic limb (e.g., encoding contact events and pressure on multiple digits). In this study, we evaluated the ability of an awake, behaving non-human primate (Macaca mulatta) to discriminate ICMS stimuli delivered on multiple electrodes spaced within somatosensory cortex. We delivered serial stimulation on single electrodes to evaluate the discriminability of sensations corresponding to ICMS of distinct cortical locations. Additionally, we delivered trains of multichannel stimulation, derived from a tactile sensor, synchronously across multiple electrodes. Our results indicate that discrimination of multiple ICMS stimuli is a challenging task, but that discriminable sensory percepts can be elicited by both single and multichannel ICMS on electrodes spaced within somatosensory cortex. PMID:27995126

  18. Spatial frames of reference and somatosensory processing: a neuropsychological perspective.

    PubMed Central

    Vallar, G

    1997-01-01

    In patients with lesions in the right hemisphere, frequently involving the posterior parietal regions, left-sided somatosensory (and visual and motor) deficits not only reflect a disorder of primary sensory processes, but also have a higher-order component related to a defective spatial representation of the body. This additional factor, related to right brain damage, is clinically relevant: contralesional hemianaesthesia (and hemianopia and hemiplegia) is more frequent in right brain-damaged patients than in patients with damage to the left side of the brain. Three main lines of investigation suggest the existence of this higher-order pathological factor. (i) Right brain-damaged patients with left hemineglect may show physiological evidence of preserved processing of somatosensory stimuli, of which they are not aware. Similar results have been obtained in the visual domain. (ii) Direction-specific vestibular, visual optokinetic and somatosensory or proprioceptive stimulations may displace spatial frames of reference in right brain-damaged patients with left hemineglect, reducing or increasing the extent of the patients' ipsilesional rightward directional error, and bring about similar directional effects in normal subjects. These stimulations, which may improve or worsen a number of manifestations of the neglect syndrome (such as extrapersonal and personal hemineglect), have similar effects on the severity of left somatosensory deficits (defective detection of tactile stimuli, position sense disorders). However, visuospatial hemineglect and the somatosensory deficits improved by these stimulations are independent, albeit related, disorders. (iii) The severity of left somatosensory deficits is affected by the spatial position of body segments, with reference to the midsagittal plane of the trunk. A general implication of these observations is that spatial (non-somatotopic) levels of representation contribute to corporeal awareness. The neural basis of these spatial

  19. Parvalbumin-producing cortical interneurons receive inhibitory inputs on proximal portions and cortical excitatory inputs on distal dendrites.

    PubMed

    Kameda, Hiroshi; Hioki, Hiroyuki; Tanaka, Yasuyo H; Tanaka, Takuma; Sohn, Jaerin; Sonomura, Takahiro; Furuta, Takahiro; Fujiyama, Fumino; Kaneko, Takeshi

    2012-03-01

    To examine inputs to parvalbumin (PV)-producing interneurons, we generated transgenic mice expressing somatodendritic membrane-targeted green fluorescent protein specifically in the interneurons, and completely visualized their dendrites and somata. Using immunolabeling for vesicular glutamate transporter (VGluT)1, VGluT2, and vesicular GABA transporter, we found that VGluT1-positive terminals made contacts 4- and 3.1-fold more frequently with PV-producing interneurons than VGluT2-positive and GABAergic terminals, respectively, in the primary somatosensory cortex. Even in layer 4, where VGluT2-positive terminals were most densely distributed, VGluT1-positive inputs to PV-producing interneurons were 2.4-fold more frequent than VGluT2-positive inputs. Furthermore, although GABAergic inputs to PV-producing interneurons were as numerous as VGluT2-positive inputs in most cortical layers, GABAergic inputs clearly preferred the proximal dendrites and somata of the interneurons, indicating that the sites of GABAergic inputs were more optimized than those of VGluT2-positive inputs. Simulation analysis with a PV-producing interneuron model compatible with the present morphological data revealed a plausible reason for this observation, by showing that GABAergic and glutamatergic postsynaptic potentials evoked by inputs to distal dendrites were attenuated to 60 and 87%, respectively, of those evoked by somatic inputs. As VGluT1-positive and VGluT2-positive axon terminals were presumed to be cortical and thalamic glutamatergic inputs, respectively, cortical excitatory inputs to PV-producing interneurons outnumbered the thalamic excitatory and intrinsic inhibitory inputs more than two-fold in any cortical layer. Although thalamic inputs are known to evoke about two-fold larger unitary excitatory postsynaptic potentials than cortical ones, the present results suggest that cortical inputs control PV-producing interneurons at least as strongly as thalamic inputs.

  20. Properties of the primary somatosensory cortex projection to the primary motor cortex in the mouse.

    PubMed

    Petrof, Iraklis; Viaene, Angela N; Sherman, S Murray

    2015-04-01

    The primary somatosensory (S1) and primary motor (M1) cortices are reciprocally connected, and their interaction has long been hypothesized to contribute to coordinated motor output. Very little is known, however, about the nature and synaptic properties of the S1 input to M1. Here we wanted to take advantage of a previously developed sensorimotor slice preparation that preserves much of the S1-to-M1 connectivity (Rocco MM, Brumberg JC. J Neurosci Methods 162: 139-147, 2007), as well as available optogenetic methodologies, in order to investigate the synaptic profile of this projection. Our data show that S1 input to pyramidal cells of M1 is highly homogeneous, possesses many features of a "driver" pathway, such as paired-pulse depression and lack of metabotropic glutamate receptor activation, and is mediated through axons that terminate in both small and large synaptic boutons. Our data suggest that S1 provides M1 with afferents that possess synaptic and anatomical characteristics ideal for the delivery of strong inputs that can "drive" postsynaptic M1 cells, thereby potentially affecting their output.

  1. Whole-brain mapping of direct inputs to midbrain dopamine neurons.

    PubMed

    Watabe-Uchida, Mitsuko; Zhu, Lisa; Ogawa, Sachie K; Vamanrao, Archana; Uchida, Naoshige

    2012-06-07

    Recent studies indicate that dopamine neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) convey distinct signals. To explore this difference, we comprehensively identified each area's monosynaptic inputs using the rabies virus. We show that dopamine neurons in both areas integrate inputs from a more diverse collection of areas than previously thought, including autonomic, motor, and somatosensory areas. SNc and VTA dopamine neurons receive contrasting excitatory inputs: the former from the somatosensory/motor cortex and subthalamic nucleus, which may explain their short-latency responses to salient events; and the latter from the lateral hypothalamus, which may explain their involvement in value coding. We demonstrate that neurons in the striatum that project directly to dopamine neurons form patches in both the dorsal and ventral striatum, whereas those projecting to GABAergic neurons are distributed in the matrix compartment. Neuron-type-specific connectivity lays a foundation for studying how dopamine neurons compute outputs.

  2. Adaptation in human somatosensory cortex as a model of sensory memory construction: a study using high-density EEG.

    PubMed

    Bradley, Claire; Joyce, Niamh; Garcia-Larrea, Luis

    2016-01-01

    Adaptation in sensory cortices has been seen as a mechanism allowing the creation of transient memory representations. Here we tested the adapting properties of early responses in human somatosensory areas SI and SII by analysing somatosensory-evoked potentials over the very first repetitions of a stimulus. SI and SII generators were identified by well-defined scalp potentials and source localisation from high-density 128-channel EEG. Earliest responses (~20 ms) from area 3b in the depth of the post-central gyrus did not show significant adaptation to stimuli repeated at 300 ms intervals. In contrast, responses around 45 ms from the crown of the gyrus (areas 1 and 2) rapidly lessened to a plateau and abated at the 20th stimulation, and activities from SII in the parietal operculum at ~100 ms displayed strong adaptation with a steady amplitude decrease from the first repetition. Although responses in both SI (1-2) and SII areas showed adapting properties and hence sensory memory capacities, evidence of sensory mismatch detection has been demonstrated only for responses reflecting SII activation. This may index the passage from an early form of sensory storage in SI to more operational memory codes in SII, allowing the prediction of forthcoming input and the triggering of a specific signal when such input differs from the previous sequence. This is consistent with a model whereby the length of temporal receptive windows increases with progression in the cortical hierarchy, in parallel with the complexity and abstraction of neural representations.

  3. 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

  4. Radial stretch reveals distinct populations of mechanosensitive mammalian somatosensory neurons

    PubMed Central

    Bhattacharya, Martha R. C.; Bautista, Diana M.; Wu, Karin; Haeberle, Henry; Lumpkin, Ellen A.; Julius, David

    2008-01-01

    Primary afferent somatosensory neurons mediate our sense of touch in response to changes in ambient pressure. Molecules that detect and transduce thermal stimuli have been recently identified, but mechanisms underlying mechanosensation, particularly in vertebrate organisms, remain enigmatic. Traditionally, mechanically evoked responses in somatosensory neurons have been assessed one cell at a time by recording membrane currents in response to application of focal pressure, suction, or osmotic challenge. Here, we used radial stretch in combination with live-cell calcium imaging to gain a broad overview of mechanosensitive neuronal subpopulations. We found that different stretch intensities activate distinct subsets of sensory neurons as defined by size, molecular markers, or pharmacological attributes. In all subsets, stretch-evoked responses required extracellular calcium, indicating that mechanical force triggers calcium influx. This approach extends the repertoire of stimulus paradigms that can be used to examine mechanotransduction in mammalian sensory neurons, facilitating future physiological and pharmacological studies. PMID:19060212

  5. Spatial coincidence modulates interaction between visual and somatosensory evoked potentials.

    PubMed

    Schürmann, Martin; Kolev, Vasil; Menzel, Kristina; Yordanova, Juliana

    2002-05-07

    The time course of interaction between concurrently applied visual and somatosensory stimulation with respect to evoked potentials (EPs) was studied. Visual stimuli, either in the left or right hemifield, and electric stimuli to the left wrist were delivered either alone or simultaneously. Visual and somatosensory EPs were summed and compared to bimodal EPs (BiEP, response to actual combination of both modalities). Temporal coincidence of stimuli lead to sub-additive or over-additive amplitudes in BiEPs in several time windows between 75 and 275 ms. Additional effects of spatial coincidence (left wrist with left hemifield) were found between 75 and 300 ms and beyond 450 ms. These interaction effects hint at a temporo-spatial pattern of multiple brain areas participating in the process of multimodal integration.

  6. 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

  7. Congenital foot deformation alters the topographic organization in the primate somatosensory system

    PubMed Central

    Liao, Chia-Chi; Qi, Hui-Xin; Reed, Jamie L.; Miller, Daniel J.; Kaas, Jon H.

    2015-01-01

    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. PMID:25326245

  8. 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.

  9. Discrimination of Finger Area of Somatosensory Cortex by NIRS

    NASA Astrophysics Data System (ADS)

    Xu, Mingdi; Hayami, Takehito; Iramina, Keiji

    We carried out a near-infrared spectroscopy (NIRS) study to observe the hemodynamic responses associated with cortical activation in the primary somatosensory cortex (SI) by finger electrical stimulation. We examined whether NIRS can assist in investigating the somatotopic arrangement of fingers on the SI hand area. We found that although relatively low in spatial resolution, NIRS can to some extent help to discriminate the representations of thumb and ring finger on the SI hand area.

  10. Touch and personality: extraversion predicts somatosensory brain response.

    PubMed

    Schaefer, Michael; Heinze, Hans-Jochen; Rotte, Michael

    2012-08-01

    The Five-Factor-Model describes human personality in five core dimensions (extraversion, neuroticism, agreeableness, conscientiousness, and openness). These factors are supposed to have different neural substrates. For example, it has been suggested that behavioral differences between introverts and extraverts can be explained by the fact that introverts exhibit an inherent drive to compensate for overactive cortical activity in reticulo-thalamo-cortical pathways. The current study examined if responses in somatosensory cortices due to tactile stimulation are affected by personality traits. Based on previous studies and theoretical models we hypothesized a relationship of extraversion with somatosensory responses in primary somatosensory cortex (SI). In order to test this hypothesis we applied nonpainful tactile stimulation on the fingers of both hands of 23 healthy young participants (mean 25 years, standard deviation ± 2.8 years). Personality traits were assessed according to the Five-Factor-Model (NEO-FFI). Neuromagnetic source imaging revealed that the cortical activity (dipole strengths) for sources in SI were closely associated with the personality trait extraversion. Thus, the less extraverted the participants were, the higher was the cortical activity in SI. This relationship was in particular valid for the right hemisphere. We conclude that personality seems to depend on primary cortex activity. Furthermore, our results provide further evidence for an inter-hemispheric asymmetry of the social brain.

  11. Somatosensory-evoked potentials and MRI in tuberculous spondylodiscitis.

    PubMed

    Titlic, M; Isgum, V; Buca, A; Kolic, K; Tonkic, A; Jukic, I; Milas, I

    2007-01-01

    Early diagnosis of spondylodiscitis is a condition of efficient conservative treatment. Somatosensory-evoked potentials with clinical examination results are used in assessing the diagnosis, as well as in monitoring the course of disease and healing. MRI clearly shows the inflammatory process, healing and scars. We report a 46-year-old woman suffering from non-specific interscapular pains. The evoked somatosensory potentials of the tibial nerveshow potential conductivity being slowed down through the thoracic spine, which is clearly evident from the prolonged latency and the decreased amplitude of the evoked response. The performed thoracic spine MRI shows spondylodiscitis at the Thl0-11 level. The subject is a nurse administering BCG therapy at a urology clinic, due to the fact of which this was deemed to have been a case of tuberculous spondylodiscitis. Due to the possibility of scattering the causative agent by needle, the biopsy was given up and antituberculous therapy was administered ex juvantibus. The disease was followed up by clinical examinations, somatosensory-evoked potentials and MRI up to fully successful and final recovery from spondylodiscitis. The above examinations are of great help in diagnosing the tuberculous spondylodiscitis and monitoring the recovery (Fig. 6, Ref. 16).

  12. 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

  13. 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

  14. The human primary somatosensory cortex response contains components related to stimulus frequency and perception in a frequency discrimination task.

    PubMed

    Liu, L C; Fenwick, P B C; Laskaris, N A; Schellens, M; PoghosyaN, V; Shibata, T; Ioannides, A A

    2003-01-01

    Somatosensory stimulation of primary somatosensory cortex (SI) using frequency discrimination offers a direct, well-defined and accessible way of studying cortical decisions at the locus of early input processing. Animal studies have identified and classified the neuronal responses in SI but they have not yet resolved whether during prolonged stimulation the collective SI response just passively reflects the input or actively participates in the comparison and decision processes. This question was investigated using tomographic analysis of single trial magnetoencephalographic data. Four right-handed males participated in a frequency discrimination task to detect changes in the frequency of an electrical stimulus applied to the right-hand digits 2+3+4. The subjects received approximately 600 pairs of stimuli with Stim1 always at 21 Hz, while Stim2 was either 21 Hz (50%) or varied from 22 to 29 Hz in steps of 1 Hz. Both stimuli were 1 s duration, separated by a 1 s interval of no stimulation. The left-SI was the most consistently activated area and showed the first activation peak at 35-48 ms after Stim1 onset and sustained activity during both stimulus periods. During the Stim2 period, we found that the left-SI activation started to differ significantly between two groups of trials (21 versus 26-29 Hz) within the first 100 ms and this difference was sustained and enhanced thereafter (approximately 600 ms). When only correct responses from the above two groups were used, the difference was even higher at later latencies (approximately 650 ms). For one subject who had enough trials of same perception to different input frequencies, e.g. responded 21 Hz to Stim2 at 21 Hz (correct) and 26-29 Hz (error), we found the sustained difference only before 650 ms. Our results suggest that SI is involved with the analysis of an input frequency and related to perception and decision at different latencies.

  15. 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.

  16. Somatosensory event-related potentials and association with tactile behavioral responsiveness patterns in children with ASD

    PubMed Central

    Cascio, Carissa J.; Gu, Chang; Schauder, Kimberly B.; Key, Alexandra P.; Yoder, Paul

    2015-01-01

    The goal of this study was to explore neural response to touch in children with and without autism spectrum disorder (ASD). Patterns of reduced (hypo-responsiveness) and enhanced (hyper-responsiveness) behavioral reaction to sensory input are prevalent in ASD, but their neural mechanisms are poorly understood. We measured event-related potentials (ERP) to a puff of air on the fingertip and collected parent report of tactile hypo- and hyper-responsiveness in children with ASD (n=21, mean(SD) age: 11.25(3.09), 2 female), and an age-matched typically developing (TD) comparison group (n=28, mean(SD) age:10.1(3.08, 2 female). A global measure of ERP response strength approximately 220–270 msec post-stimulus was associated with tactile hypo-responsiveness in ASD, while tactile hyper-responsiveness was associated with earlier neural response (approximately 120–220 msec post-stimulus) in both groups. These neural responses also related to autism severity. These results suggest that, in ASD, tactile hypo- and hyper-responsiveness may reflect different waypoints in the neural processing stream of sensory input. The timing of the relationship for hyper-responsiveness is consistent with somatosensory association cortical response, while that for hypo-responsiveness is more consistent with later processes that may involve allocation of attention or emotional valence to the stimulus. PMID:26016951

  17. Age-dependent modulation of the somatosensory network upon eye closure.

    PubMed

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

    2016-02-01

    Eye closure even in complete darkness can improve somatosensory perception by switching the brain to a uni-sensory processing mode. This causes an increased information flow between the thalamus and the somatosensory cortex while decreasing modulation by the visual cortex. Previous work suggests that these modulations are age-dependent and that the benefit in somatosensory performance due to eye closing diminishes with age. The cause of this age-dependency and to what extent somatosensory processing is involved remains unclear. Therefore, we intended to characterize the underlying age-dependent modifications in the interaction and connectivity of different sensory networks caused by eye closure. We performed functional MR-imaging with tactile stimulation of the right hand under the conditions of opened and closed eyes in healthy young and elderly participants. Conditional Granger causality analysis was performed to assess the somatosensory and visual networks, including the thalamus. Independent of age, eye closure improved the information transfer from the thalamus to and within the somatosensory cortex. However, beyond that, we found an age-dependent recruitment strategy. Whereas young participants were characterized by an optimized information flow within the relays of the somatosensory network, elderly participants revealed a stronger modulatory influence of the visual network upon the somatosensory cortex. Our results demonstrate that the modulation of the somatosensory and visual networks by eye closure diminishes with age and that the dominance of the visual system is more pronounced in the aging brain.

  18. Increased cortical responses to forepaw stimuli immediately after peripheral deafferentation of hindpaw inputs

    PubMed Central

    Humanes-Valera, D.; Foffani, G.; Aguilar, J.

    2014-01-01

    Both central and peripheral injuries of the nervous system induce dramatic reorganization of the primary somatosensory cortex. We recently showed that spinal cord injuries at thoracic level in anesthetized rats can immediately increase the responses evoked in the forepaw cortex by forepaw stimuli (above the level of the lesion), suggesting that the immediate cortical reorganization after deafferentation can extend across cortical representations of different paws. Here we show that a complete deafferentation of inputs from the hindpaw induced by injury or pharmacological block of the peripheral nerves in anesthetized rats also increases the responses evoked in the forepaw cortex by forepaw stimuli. This increase of cortical responses after peripheral deafferentation is not associated with gross alterations in the state of cortical spontaneous activity. The results of the present study, together with our previous works on spinal cord injury, suggest that the forepaw somatosensory cortex is critically involved in the reorganization that starts immediately after central or peripheral deafferentation of hindpaw inputs. PMID:25451619

  19. Dual function conducting polymer diodes

    DOEpatents

    Heeger, Alan J.; Yu, Gang

    1996-01-01

    Dual function diodes based on conjugated organic polymer active layers are disclosed. When positively biased the diodes function as light emitters. When negatively biased they are highly efficient photodiodes. Methods of preparation and use of these diodes in displays and input/output devices are also disclosed.

  20. 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

  1. 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.

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

    PubMed

    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.

  3. [Somatotopy and information processing in the somatosensory cortex].

    PubMed

    Iwamura, Yoshiaki

    2009-12-01

    The present article reviews studies on the somatotopic representation of the body in the postcentral gyrus. The review consists of 3 sections namely the early studies on the cortical localization of somatosensory in humans and animals, earlier neurophysiological studies in monkeys by recording single units, and more recent studies in human subjects. Results of the neurophysiological studies in monkeys established a hierarchical scheme of information processing and have guided the latest studies on human subjects that use various modern techniques such as neuroimaging. This review illustrates the origin of the concept of somatotopic representation of the body, its utilization in the later cortical mapping studies, and what is the reality of the concept.

  4. The perception of pain in others suppresses somatosensory oscillations: a magnetoencephalography study.

    PubMed

    Cheng, Yawei; Yang, Chia-Yen; Lin, Ching-Po; Lee, Po-Lei; Decety, Jean

    2008-05-01

    Accumulating evidence demonstrates that similar neural circuits are activated during the first-hand experience of pain and the observation of pain in others. However, most functional MRI studies did not detect signal change in the primary somatosensory cortex during pain empathy. To test if the perception of pain in others involves the primary somatosensory cortex, neuromagnetic oscillatory activity was recorded from the primary somatosensory cortex in 16 participants while they observed static pictures depicting body parts in painful and non-painful situations. The left median nerve was stimulated at the wrist, and the poststimulus rebounds of the approximately 10-Hz somatosensory cortical oscillations were quantified. Compared to the baseline condition, the level of the approximately 10-Hz oscillations was suppressed during both of the observational situations, indicating the activation of the primary somatosensory cortex. Importantly, watching painful compared to non-painful situations suppressed somatosensory oscillations to a significant stronger degree. In addition, the suppression caused by perceiving others in the painful relative to the non-painful situations correlated with the perspective taking subscale of the interpersonal reaction index. These results, consistent with the mirror-neuron system, demonstrate that the perception of pain in others modulates neural activity in primary somatosensory cortex and supports the idea that the perception of pain in others elicits subtle somatosensory activity that may be difficult to detect by fMRI techniques.

  5. 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.

  6. 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

  7. Transcranial Direct Current Stimulation Over the Primary and Secondary Somatosensory Cortices Transiently Improves Tactile Spatial Discrimination in Stroke Patients.

    PubMed

    Fujimoto, Shuhei; Kon, Noriko; Otaka, Yohei; Yamaguchi, Tomofumi; Nakayama, Takeo; Kondo, Kunitsugu; Ragert, Patrick; Tanaka, Satoshi

    2016-01-01

    In healthy subjects, dual hemisphere transcranial direct current stimulation (tDCS) over the primary (S1) and secondary somatosensory cortices (S2) has been found to transiently enhance tactile performance. However, the effect of dual hemisphere tDCS on tactile performance in stroke patients with sensory deficits remains unknown. The purpose of this study was to investigate whether dual hemisphere tDCS over S1 and S2 could enhance tactile discrimination in stroke patients. We employed a double-blind, crossover, sham-controlled experimental design. Eight chronic stroke patients with sensory deficits participated in this study. We used a grating orientation task (GOT) to measure the tactile discriminative threshold of the affected and non-affected index fingers before, during, and 10 min after four tDCS conditions. For both the S1 and S2 conditions, we placed an anodal electrode over the lesioned hemisphere and a cathodal electrode over the opposite hemisphere. We applied tDCS at an intensity of 2 mA for 15 min in both S1 and S2 conditions. We included two sham conditions in which the positions of the electrodes and the current intensity were identical to that in the S1 and S2 conditions except that current was delivered for the initial 15 s only. We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition. GOT thresholds were not significantly different between the S1 and S2 conditions at any time point. We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction.

  8. Transcranial Direct Current Stimulation Over the Primary and Secondary Somatosensory Cortices Transiently Improves Tactile Spatial Discrimination in Stroke Patients

    PubMed Central

    Fujimoto, Shuhei; Kon, Noriko; Otaka, Yohei; Yamaguchi, Tomofumi; Nakayama, Takeo; Kondo, Kunitsugu; Ragert, Patrick; Tanaka, Satoshi

    2016-01-01

    In healthy subjects, dual hemisphere transcranial direct current stimulation (tDCS) over the primary (S1) and secondary somatosensory cortices (S2) has been found to transiently enhance tactile performance. However, the effect of dual hemisphere tDCS on tactile performance in stroke patients with sensory deficits remains unknown. The purpose of this study was to investigate whether dual hemisphere tDCS over S1 and S2 could enhance tactile discrimination in stroke patients. We employed a double-blind, crossover, sham-controlled experimental design. Eight chronic stroke patients with sensory deficits participated in this study. We used a grating orientation task (GOT) to measure the tactile discriminative threshold of the affected and non-affected index fingers before, during, and 10 min after four tDCS conditions. For both the S1 and S2 conditions, we placed an anodal electrode over the lesioned hemisphere and a cathodal electrode over the opposite hemisphere. We applied tDCS at an intensity of 2 mA for 15 min in both S1 and S2 conditions. We included two sham conditions in which the positions of the electrodes and the current intensity were identical to that in the S1 and S2 conditions except that current was delivered for the initial 15 s only. We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition. GOT thresholds were not significantly different between the S1 and S2 conditions at any time point. We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction. PMID:27064531

  9. 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.

  10. The human somatosensory system: from perception to decision making.

    PubMed

    Pleger, Burkhard; Villringer, Arno

    2013-04-01

    Pioneering human and animal research has yielded a better understanding of the brain networks involved in somatosensory perception and decision making. New methodical achievements in combination with computational formalization allow research questions to be addressed which increasingly reflect not only the complex sensory demands of real environments, but also the cognitive ones. Here, we review the latest research on somatosensory perception and decision making with a special focus on the recruitment of supplementary brain networks which are dependent on the situation-associated sensory and cognitive demands. We also refer to literature on sensory-motor integration processes during visual decision making to delineate the complexity and dynamics of how sensory information is relayed to the motor output system. Finally, we review the latest literature which provides novel evidence that other everyday life situations, such as semantic decision making or social interactions, appear to depend on tactile experiences; suggesting that the sense of touch, being the first sense to develop ontogenetically, may essentially support later development of other conceptual knowledge.

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

    PubMed Central

    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

  12. Brain micromotion around implants in the rodent somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Gilletti, Aaron; Muthuswamy, Jit

    2006-09-01

    The magnitude of brain tissue micromotion relative to stationary brain implants and its impact on the viability and function of the surrounding brain tissue due to mechanical stresses is poorly understood. The central goal of this study is to characterize surface micromotion in the somatosensory cortex against stationary cylindrical implants. We used a differential variable reluctance transducer (DVRT) in adult rats (n = 6) to monitor micromotion normal to the somatosensory cortex surface. Experiments were performed both in the presence and in the absence of dura mater and displacement measurements were made at three different locations within craniotomies of two different sizes. In anesthetized rats, pulsatile surface micromotion was observed to be in the order of 10-30 µm due to pressure changes during respiration and 2-4 µm due to vascular pulsatility. Brain displacement values due to respiration were significantly lower in the presence of the dura compared to those without the dura. In addition, large inward displacements of brain tissue between 10-60 µm were observed in n = 3 animals immediately following the administration of anesthesia. Such significant micromotion can impact a wide variety of acute and chronic procedures involving any brain implants, precise neurosurgery or imaging and therefore has to be factored in the design of such procedures.

  13. 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

  14. A cognitive neuroprosthetic that uses cortical stimulation for somatosensory feedback

    NASA Astrophysics Data System (ADS)

    Klaes, Christian; Shi, Ying; Kellis, Spencer; Minxha, Juri; Revechkis, Boris; Andersen, Richard A.

    2014-10-01

    Objective. Present day cortical brain-machine interfaces (BMIs) have made impressive advances using decoded brain signals to control extracorporeal devices. Although BMIs are used in a closed-loop fashion, sensory feedback typically is visual only. However medical case studies have shown that the loss of somesthesis in a limb greatly reduces the agility of the limb even when visual feedback is available. Approach. To overcome this limitation, this study tested a closed-loop BMI that utilizes intracortical microstimulation to provide ‘tactile’ sensation to a non-human primate. Main result. Using stimulation electrodes in Brodmann area 1 of somatosensory cortex (BA1) and recording electrodes in the anterior intraparietal area, the parietal reach region and dorsal area 5 (area 5d), it was found that this form of feedback can be used in BMI tasks. Significance. Providing somatosensory feedback has the poyential to greatly improve the performance of cognitive neuroprostheses especially for fine control and object manipulation. Adding stimulation to a BMI system could therefore improve the quality of life for severely paralyzed patients.

  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. Somatosensory eye blink reflex in peripheral facial palsy.

    PubMed

    Erkol, Gökhan; Kiziltan, Meral E; Uluduz, Derya; Uzun, Nurten

    2009-09-04

    To investigate the association between somatosensory blink reflex (SBR) and peripheral facial palsy (PFP) severity and trigeminal blink reflex (BR) changes in cases with PFP and subsequent postparalytic facial syndrome development (PFS). One hundred and twenty subjects with peripheral facial palsy and post-facial syndrome and 44 age and gender matched healthy volunteers were enrolled to this study. Blink reflexes and somatosensory blink reflex were studied in all. The association between R1 and R2 responses of the BR and SBR positivity was investigated. SBR was elicited in 36.3% of normal subjects, in 18.3% of PFP and in 65.3% of PFS patients. In the paralytic side, the frequency of SBR positivity was significantly lower in PFP group compared to controls and SBR was most frequently observed in patients with PFS. Compared to PFP and control groups, SBR positivity on the non-paralytic side significantly revealed a higher rate in PFS patients. SBR positivity of patients in whom R1 or R2 were absent, was significantly lower than those subjects with prolonged or normal R1 or R2 responses. PFP and successive PFS are good models for the sensory motor gate mechanisms and/or excitability enhancement of brainstem neurons responsible for SBR.

  17. Identification of the source of the bilateral projection system from cortex to somatosensory neostriatum and an exploration of its physiological actions.

    PubMed

    Wright, A K; Ramanathan, S; Arbuthnott, G W

    2001-01-01

    Microinjections of cholera toxin B subunit were made into the area of the neostriatum that receives input from the primary somatosensory barrel cortex (SI) in the rat. Studies of the cortices then allowed retrograde identification of the cortical cells supplying the striatal input. When injections were restricted to the neostriatum, retrograde labelling was found in layer V of both SI cortices. Ipsilateral to the injection, cells were retrogradely filled with toxin in all parts of the barrel field, in adjacent parietal cortex, in the motor cortex and in prefrontal areas. A similar distribution across cortical areas was seen contralaterally; however, the stained cells in the SI were between rather than within barrel columns. An earlier anterograde study suggested two inputs from the SI to the neostriatum. The present results indicate that one input to the somatosensory area of the neostriatum arises bilaterally from neurons between the barrels of the SI, while the topographic pathway from below the barrels is present only ipsilaterally. These anatomical results indicate that separate stimulation of the two corticostriatal pathways from the barrel cortex is possible. Electrical stimulation of the contralateral cortex will activate the bilateral pathway, while electrical stimulation of the whisker pads activates the barrels and hence the topographic pathway. Neurons in the somatosensory region of the striatum responded to stimuli in the contralateral cortex and in the contralateral whisker pad. In spite of very different path lengths, stimuli via the two routes gave rise to excitatory postsynaptic potentials in the striatal cells with similar latencies. The excitatory postsynaptic potentials to whisker pad stimulation had a rapid rise time and usually resulted in at least one action potential. Responses to stimulation of the contralateral cortex rose to a peak more slowly and were more variable in latency, but also gave rise to an action potential in the majority of

  18. Large-Scale Expansion of the Face Representation in Somatosensory Areas of the Lateral Sulcus Following Spinal Cord Injuries in Monkeys

    PubMed Central

    Tandon, Shashank; Kambi, Niranjan; Lazar, Leslee; Mohammed, Hisham; Jain, Neeraj

    2009-01-01

    Transection of dorsal columns of the spinal cord in adult monkeys results in large-scale expansion of the face inputs into the deafferented hand region in the primary somatosensory cortex (area 3b) and the ventroposterior nucleus of thalamus. Here we determined if the upstream cortical areas, secondary somatosensory (S2) and parietal ventral (PV) areas, also undergo reorganization following lesions of the dorsal columns. Areas S2, PV and 3b were mapped after long-term unilateral lesions of the dorsal columns at cervical levels in adult macaque monkeys. In areas S2 and PV, we found neurons responding to touch on the face in regions where normally responses to touch on the hand and other body parts are seen. In the reorganized parts of S2 and PV inputs from the chin as well as other parts of the face were observed, whereas, in area 3b only the chin inputs expand into the deafferented regions. The results show that deafferentations lead to a more widespread brain reorganization than previously known. The data also show that reorganization in areas S2 and PV shares a common substrate with area 3b, but there are specific features that emerge in S2 and PV. PMID:19776287

  19. Somatosensory Electrical Stimulation Does Not Augment Motor Skill Acquisition and Intermanual Transfer in Healthy Young Adults - A Pilot Study.

    PubMed

    Négyesi, János; Veldman, Menno P; Berghuis, Kelly M M; Javet, Marie; Tihanyi, József; Hortobágyi, Tibor

    2017-03-24

    Sensory input can modify motor function and magnify interlimb transfer. We examined the effects of low-intensity somatosensory electrical stimulation (SES) on motor practice-induced (MP) skill acquisition and intermanual transfer. Participants practiced a visuomotor skill for 25 minutes and received SES to the practice or the transfer arm. Responses to single- and double pulse transcranial magnetic stimulation (TMS) were measured in both extensor carpi radialis. SES did not further increase skill acquisition (RMP: 30.8%, RMP+RSES: 27.8%) and intermanual transfer (RMP: 13.6%, RMP+RSES: 9.8%) when delivered to the left arm (RMP+LSES: 44.8%, 18.6%, respectively). Furthermore, TMS measures revealed no changes in either hand. Future studies should systematically manipulate SES parameters to better understand the mechanisms of how SES affords motor learning benefits documented but not studied in patients.

  20. Developmental alterations in noxious-evoked EEG activity recorded from rat primary somatosensory cortex.

    PubMed

    Devonshire, I M; Greenspon, C M; Hathway, G J

    2015-10-01

    Primary somatosensory cortex (S1) contains a nociceptive map that localizes potential tissue damage on the body and encodes stimulus intensity. An objective and specific biomarker of pain however is currently lacking and is urgently required for use in non-verbal clinical populations as well as in the validation of pre-clinical pain models. Here we describe studies to see if the responses of the S1 in juvenile rats are different to those in the adult. We recorded electroencephalogram (EEG) responses from S1 of lightly-anesthetized Sprague-Dawley rats at either postnatal day 21 or postnatal day 40 during the presentation of noxious (55 °C) or innocuous (30 °C) thermal stimuli applied to the plantar surface of the left hindpaw. The total EEG power across the recording period was the same in both ages after stimulation but the frequency distribution was significantly affected by age. Noxious heat evoked a significant increase in theta band (4-8 Hz) activity in adults only (P<0.0001 compared to baseline; P<0.0001 compared to juveniles). There were no significant differences in EEG responses to innocuous thermal stimuli. These data show that there are significant alterations in the processing of nociceptive inputs within the maturing cortex and that cortical theta activity is involved only in the adult cortical response to noxious stimulation.

  1. Exploring neuro-vascular and neuro-metabolic coupling in rat somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Mesquita, R. C.; Huppert, T. J.; Boas, D. A.

    2009-01-01

    The existence of a coupling between changes in neuronal activity, cerebral blood flow and blood oxygenation is well known. The explicit relationship between these systems, however, is complex and remains a subject of intense research. Here, we use direct electrophysiological recordings to predict blood flow and oxygenation changes measured with optical methods during parametric stimulation applied to the somatosensory cortex in rat brain. Using a multimodal model of the cerebral functional unit, we estimate a neuro-vascular and a neuro-metabolic transfer function relating the experimentally measured neural responses with the inputs to a vascular model predicting hemodynamic and blood oxygenation changes. We show that our model can accurately predict experimentally measured parametric hemodynamic evoked responses by using a single linear transfer function relationship with a reduced number of state parameters to relate the level of neural activity to evoked cerebral blood flow and oxygen metabolism changes. At the same time, we characterize the metabolic and vascular neural response functions and interpret their physiological significance.

  2. Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers.

    PubMed

    Bhattacharjee, Arindam; Ye, Amanda J; Lisak, Joy A; Vargas, Maria G; Goldreich, Daniel

    2010-10-27

    Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at ∼100 ms intervals, and adjacent raised dots within a character at 50 ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25 ms target tap) and amplitude discrimination (compared with 100 μm reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker, 50 Hz, 50 μm; target-masker delays, ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged but that perceptual processing is accelerated in congenitally blind Braille readers.

  3. A Recurrent Network Model of Somatosensory Parametric Working Memory in the Prefrontal Cortex

    PubMed Central

    Miller, Paul; Brody, Carlos D; Romo, Ranulfo; Wang, Xiao-Jing

    2015-01-01

    A parametric working memory network stores the information of an analog stimulus in the form of persistent neural activity that is monotonically tuned to the stimulus. The family of persistent firing patterns with a continuous range of firing rates must all be realizable under exactly the same external conditions (during the delay when the transient stimulus is withdrawn). How this can be accomplished by neural mechanisms remains an unresolved question. Here we present a recurrent cortical network model of irregularly spiking neurons that was designed to simulate a somatosensory working memory experiment with behaving monkeys. Our model reproduces the observed positively and negatively monotonic persistent activity, and heterogeneous tuning curves of memory activity. We show that fine-tuning mathematically corresponds to a precise alignment of cusps in the bifurcation diagram of the network. Moreover, we show that the fine-tuned network can integrate stimulus inputs over several seconds. Assuming that such time integration occurs in neural populations downstream from a tonically persistent neural population, our model is able to account for the slow ramping-up and ramping-down behaviors of neurons observed in prefrontal cortex. PMID:14576212

  4. Subplate neurons promote spindle bursts and thalamocortical patterning in the neonatal rat somatosensory cortex

    PubMed Central

    Tolner, Else A.; Sheikh, Aminah; Yukin, Alexey Y.; Kaila, Kai; Kanold, Patrick

    2012-01-01

    Patterned neuronal activity such as spindle bursts in the neonatal cortex is likely to promote the maturation of cortical synapses and neuronal circuits. Previous work on cats has shown that removal of subplate neurons, a transient neuronal population in the immature cortex, prevents the functional maturation of thalamocortical and intracortical connectivity. Here we studied the effect of subplate removal in the neonatal rat somatosensory cortex (S1). Using intracortical EEG we show that after selective removal of subplate neurons in the limb region of S1, endogenous and sensory evoked spindle burst activity is largely abolished. Consistent with the reduced in vivo activity in the S1 limb region, we find by in vitro recordings that thalamocortical inputs to layer 4 neurons are weak. In addition, we find that removal of subplate neurons in the S1 barrel region prevents the development of the characteristic histological barrel-like appearance. Thus, subplate neurons are crucially involved in the generation of particular types of early network activity in the neonatal cortex, which are an important feature of cortical development. The altered EEG pattern following subplate damage could be applicable in the neurological assessment of human neonates. PMID:22238105

  5. Altered Onset Response Dynamics in Somatosensory Processing in Autism Spectrum Disorder

    PubMed Central

    Khan, Sheraz; Hashmi, Javeria A.; Mamashli, Fahimeh; Bharadwaj, Hari M.; Ganesan, Santosh; Michmizos, Konstantinos P.; Kitzbichler, Manfred G.; Zetino, Manuel; Garel, Keri-Lee A.; Hämäläinen, Matti S.; Kenet, Tal

    2016-01-01

    Abnormalities in cortical connectivity and evoked responses have been extensively documented in autism spectrum disorder (ASD). However, specific signatures of these cortical abnormalities remain elusive, with data pointing toward abnormal patterns of both increased and reduced response amplitudes and functional connectivity. We have previously proposed, using magnetoencephalography (MEG) data, that apparent inconsistencies in prior studies could be reconciled if functional connectivity in ASD was reduced in the feedback (top-down) direction, but increased in the feedforward (bottom-up) direction. Here, we continue this line of investigation by assessing abnormalities restricted to the onset, feedforward inputs driven, component of the response to vibrotactile stimuli in somatosensory cortex in ASD. Using a novel method that measures the spatio-temporal divergence of cortical activation, we found that relative to typically developing participants, the ASD group was characterized by an increase in the initial onset component of the cortical response, and a faster spread of local activity. Given the early time window, the results could be interpreted as increased thalamocortical feedforward connectivity in ASD, and offer a plausible mechanism for the previously observed increased response variability in ASD, as well as for the commonly observed behaviorally measured tactile processing abnormalities associated with the disorder. PMID:27375417

  6. Receptive Field Properties of the Macaque Second Somatosensory Cortex: Evidence for Multiple Functional Representations

    PubMed Central

    Fitzgerald, Paul J.; Lane, John W.; Thakur, Pramodsingh H.; Hsiao, Steven S.

    2007-01-01

    The detailed functional organization of the macaque second somatosensory cortex (SII) is not well understood. Here we report the results of a study of the functional organization of the SII hand region that combines microelectrode mapping using hand-held stimuli with single-unit recordings using a motorized, computer-controlled tactile oriented bar. The data indicate that the SII hand region extends ~10 mm in the anteroposterior (AP) dimension, primarily within the upper bank of the lateral sulcus. Furthermore, we find evidence that this region consists of multiple functional fields, with a central field containing neurons that are driven well by cutaneous stimuli, flanked by an anterior field and a posterior field that each contain neurons that are driven well by proprioceptive stimuli and less well by cutaneous stimuli. The anterior field extends ~4 –5 mm AP, the central field extends ~3– 4 mm, and the posterior field extends ~3 mm. Data from the motorized stimulator indicate that neurons in the central field are more responsive to oriented bars, more frequently exhibit orientation tuning, and have larger receptive fields than neurons in the anterior and posterior fields. We speculate that the three putative fields play different functional roles in tactile perception; the anterior and posterior fields process information that involves both proprioceptive and cutaneous input such as sensorimotor integration or stereognosis, whereas the central field processes primarily cutaneous information. PMID:15590936

  7. Rat claustrum coordinates but does not integrate somatosensory and motor cortical information.

    PubMed

    Smith, Jared B; Radhakrishnan, Harsha; Alloway, Kevin D

    2012-06-20

    The function of the claustrum is a fundamental issue in neuroscience. Anatomical data indicate that the rat claustrum is part of an interhemispheric circuit that could be involved in the bilateral coordination of whisker movements. Given that whisking is a somesthetic-guided motor behavior, the goal of the current study was to elucidate the connections of the claustrum with respect to the whisker representations in the primary somatosensory (wSI) and motor (wMI) cortical areas. Anterograde tracer injections showed that wMI projects most densely to the claustrum in the contralateral hemisphere, whereas wSI does not project to the claustrum in either hemisphere. Injections of different retrograde tracers into wMI and wSI of the same animal revealed intermingled populations of labeled neurons in the claustrum, as well as many double-labeled neurons. This indicates that the same part of the claustrum projects to the whisker representations in both SI and MI. Finally, injections of different anterograde tracers in the wMI regions of both hemispheres were combined with a retrograde tracer injection in wSI, and this produced dense terminal labeling around retrogradely labeled neurons in the claustrum of both hemispheres. Although the rodent claustrum is probably involved in the interhemispheric coordination of the MI and SI whisker representations, it does not receive inputs from both of these cortical regions. Hence, the claustrum should not be universally regarded as an integrator of somesthetic and motor information.

  8. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  9. MDS MIC Catalog Inputs

    NASA Technical Reports Server (NTRS)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  10. Talking Speech Input.

    ERIC Educational Resources Information Center

    Berliss-Vincent, Jane; Whitford, Gigi

    2002-01-01

    This article presents both the factors involved in successful speech input use and the potential barriers that may suggest that other access technologies could be more appropriate for a given individual. Speech input options that are available are reviewed and strategies for optimizing use of speech recognition technology are discussed. (Contains…

  11. Double anterograde tracing of outputs from adjacent "barrel columns" of rat somatosensory cortex. Neostriatal projection patterns and terminal ultrastructure.

    PubMed

    Wright, A K; Norrie, L; Ingham, C A; Hutton, E A; Arbuthnott, G W

    1999-01-01

    The sensory input to the neostriatum from groups of cortical cells related to individual facial vibrissae has been investigated at both light- and electron-microscopic resolution. The purpose of the study was to establish the extent to which corticostriatal input maintains the anatomical coding of spatial information that is present in cortex. A double anterograde tracing method was used to identify the output projections from groups of adjacent neurons in different barrel columns, so that the anatomical relationships between two groups could be studied throughout their length. Adjacent whiskers are represented in adjoining cortical barrels and an examination of corticostriatal projections from these reveals two patterns of projection. In one, the anatomical topography is partially preserved; the barrels are represented in adjoining, discrete, areas of the somatosensory neostriatum. In the second projection pattern, the neostriatal innervation is diffuse and adjacent barrels are represented in overlapping regions of the neostriatum. Moreover, the fibres are thinner, have smaller boutons, and are present in both the ipsilateral and contralateral neostriatum. The two systems also enter the neostriatal neuropile separately. The discrete topographic system enters the adjacent neostriatum as collaterals which leave the descending corticofugal fibres at right angles, while the diffuse system enters directly from the corpus callosum at an acute angle. Examination of the neostriatal terminal fields by correlated light and electron microscopy, shows that characteristic axospinous terminals on spiny neurons are made by both groups of cortical fibres, although they differ in their size and morphology. It is concluded that at least two corticostriatal pathways arise from the barrel cortex. One connection maintains some of the anatomical code implicit in the barrel pattern of primary somatosensory cortex, but another, more diffuse, system is overlaid upon it which may carry

  12. 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.

  13. UWB dual burst transmit driver

    SciTech Connect

    Dallum, Gregory E; Pratt, Garth C; Haugen, Peter C; Zumstein, James M; Vigars, Mark L; Romero, Carlos E

    2012-04-17

    A dual burst transmitter for ultra-wideband (UWB) communication systems generates a pair of precisely spaced RF bursts from a single trigger event. An input trigger pulse produces two oscillator trigger pulses, an initial pulse and a delayed pulse, in a dual trigger generator. The two oscillator trigger pulses drive a gated RF burst (power output) oscillator. A bias driver circuit gates the RF output oscillator on and off and sets the RF burst packet width. The bias driver also level shifts the drive signal to the level that is required for the RF output device.

  14. Deciphering laminar-specific neural inputs with line-scanning fMRI

    PubMed Central

    Yu, Xin; Qian, Chunqi; Chen, Der-yow; Dodd, Stephen; Koretsky, Alan P.

    2014-01-01

    Using a line-scanning method during functional magnetic resonance imaging (fMRI) we obtain high temporal (50 ms) and spatial (50 μm) resolution information along the cortical thickness, and show that the laminar position of fMRI onset coincides with distinct neural inputs t in therat somatosensory and motor cortices. This laminar specific fMRI onset allowed the identification of the neural inputs underlying ipsilateral fMRI activation in the barrel cortex due to peripheral denervation-induced plasticity. PMID:24240320

  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

    resulting from prolonged bed-rest impacts functional performance particularly for tests with a greater requirement for postural equilibrium control. These changes in functional performance were paralleled by similar decrement in tests designed to specifically assess postural equilibrium and dynamic gait control. These results indicate that body support unloading experienced during space flight plays a central role in postflight alteration of functional task performance. These data also support the concept that space flight may cause central adaptation of converging body-load somatosensory and vestibular input during gravitational transitions.

  16. Cellular mechanisms for response heterogeneity among L2/3 pyramidal cells in whisker somatosensory cortex.

    PubMed

    Elstrott, Justin; Clancy, Kelly B; Jafri, Haani; Akimenko, Igor; Feldman, Daniel E

    2014-07-15

    Whisker deflection evokes sparse, low-probability spiking among L2/3 pyramidal cells in rodent somatosensory cortex (S1), with spiking distributed nonuniformly between more and less responsive cells. The cellular and local circuit factors that determine whisker responsiveness across neurons are unclear. To identify these factors, we used two-photon calcium imaging and loose-seal recording to identify more and less responsive L2/3 neurons in S1 slices in vitro, during feedforward recruitment of the L2/3 network by L4 stimulation. We observed a broad gradient of spike recruitment thresholds within local L2/3 populations, with low- and high-threshold cells intermixed. This recruitment gradient was significantly correlated across different L4 stimulation sites, and between L4-evoked and whisker-evoked responses in vivo, indicating that a substantial component of responsiveness is independent of tuning to specific feedforward inputs. Low- and high-threshold L2/3 pyramidal cells differed in L4-evoked excitatory synaptic conductance and intrinsic excitability, including spike threshold and the likelihood of doublet spike bursts. A gradient of intrinsic excitability was observed across neurons. Cells that spiked most readily to L4 stimulation received the most synaptic excitation but had the lowest intrinsic excitability. Low- and high-threshold cells did not differ in dendritic morphology, passive membrane properties, or L4-evoked inhibitory conductance. Thus multiple gradients of physiological properties exist across L2/3 pyramidal cells, with excitatory synaptic input strength best predicting overall spiking responsiveness during network recruitment.

  17. A MEG investigation of somatosensory processing in the rhesus monkey

    PubMed Central

    Wilson, Tony W.; Godwin, Dwayne W.; Czoty, Paul W.; Nader, Michael A.; Kraft, Robert A.; Buchheimer, Nancy C.; Daunais, James B.

    2009-01-01

    The use of minimally and non-invasive neuroimaging methods in animal models has sharply increased over the past decade. Such studies have enhanced understanding of the neural basis of the physical signals quantified by these tools, and have addressed an assortment of fundamental and otherwise intractable questions in neurobiology. To date, these studies have almost exclusively utilized positron-emission tomography or variants of magnetic resonance based imaging. These methods provide largely indirect measures of brain activity and are strongly reliant on intact vasculature and normal blood flow, which is known to be compromised in many clinical conditions. The current study provides the first demonstration of whole-head magnetoencephalography (MEG), a non-invasive and direct measure of neuronal activity, in a rhesus monkey, and in the process supplies the initial data on systems-level dynamics in somatosensory cortices. An adult rhesus monkey underwent three separate studies of tactile stimulation on the pad of the right second or fifth digit as whole-head MEG data were acquired. The neural generators of the primary neuromagnetic components were localized using an equivalent-current-dipole model. Second digit stimulation produced an initial cortical response peaking ∼16 ms after stimulus onset in the contralateral somatosensory cortices, with a later response at ∼96 ms in an overlapping or nearby neural area with a roughly orthogonal orientation. Stimulation of the fifth digit produced similar results, the main exception being a substantially weaker later response. We believe the 16ms response is likely the monkey homologue of the human M50 response, as both are the earliest cortical response and localize to the contralateral primary somatosensory area. Thus, these data suggest that mechanoreception in nonhuman primates operates substantially faster than that in adult humans. More broadly, these results demonstrate that it is feasible to use current human whole

  18. A MEG investigation of somatosensory processing in the rhesus monkey.

    PubMed

    Wilson, Tony W; Godwin, Dwayne W; Czoty, Paul W; Nader, Michael A; Kraft, Robert A; Buchheimer, Nancy C; Daunais, James B

    2009-07-15

    The use of minimally and non-invasive neuroimaging methods in animal models has sharply increased over the past decade. Such studies have enhanced understanding of the neural basis of the physical signals quantified by these tools, and have addressed an assortment of fundamental and otherwise intractable questions in neurobiology. To date, these studies have almost exclusively utilized positron-emission tomography or variants of magnetic resonance based imaging. These methods provide largely indirect measures of brain activity and are strongly reliant on intact vasculature and normal blood-flow, which is known to be compromised in many clinical conditions. The current study provides the first demonstration of whole-head magnetoencephalography (MEG), a non-invasive and direct measure of neuronal activity, in a rhesus monkey, and in the process supplies the initial data on systems-level dynamics in somatosensory cortices. An adult rhesus monkey underwent three separate studies of tactile stimulation on the pad of the right second or fifth digit as whole-head MEG data were acquired. The neural generators of the primary neuromagnetic components were localized using an equivalent-current-dipole model. Second digit stimulation produced an initial cortical response peaking approximately 16 ms after stimulus onset in the contralateral somatosensory cortices, with a later response at approximately 96 ms in an overlapping or nearby neural area with a roughly orthogonal orientation. Stimulation of the fifth digit produced similar results, the main exception being a substantially weaker later response. We believe the 16 ms response is likely the monkey homologue of the human M50 response, as both are the earliest cortical response and localize to the contralateral primary somatosensory area. Thus, these data suggest that mechanoreception in nonhuman primates operates substantially faster than that in adult humans. More broadly, these results demonstrate that it is feasible to

  19. 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

  20. Children with Autism Show Reduced Somatosensory Response: An MEG Study

    PubMed Central

    Marco, Elysa J.; Khatibi, Kasra; Hill, Susanna S.; Siegel, Bryna; Arroyo, Monica S.; Dowling, Anne F.; Neuhaus, John M.; Sherr, Elliott H.; Hinkley, Leighton N. B.; Nagarajan, Srikantan S.

    2012-01-01

    Lay Abstract Autism spectrum disorders are reported to affect nearly one out of every one hundred children, with over 90% of these children showing behavioral disturbances related to the processing of basic sensory information. Behavioral sensitivity to light touch, such as profound discomfort with clothing tags and physical contact, is a ubiquitous finding in children on the autism spectrum. In this study, we investigate the strength and timing of brain activity in response to simple, light taps to the fingertip. Our results suggest that children with autism show a diminished early response in the primary somatosensory cortex (S1). This finding is most evident in the left hemisphere. In exploratory analysis, we also show that tactile sensory behavior, as measured by the Sensory Profile, may be a better predictor of the intensity and timing of brain activity related to touch than a clinical autism diagnosis. We report that children with atypical tactile behavior have significantly lower amplitude somatosensory cortical responses in both hemispheres. Thus sensory behavioral phenotype appears to be a more powerful strategy for investigating neural activity in this cohort. This study provides evidence for atypical brain activity during sensory processing in autistic children and suggests that our sensory behavior based methodology may be an important approach to investigating brain activity in people with autism and neurodevelopmental disorders. Scientific Abstract The neural underpinnings of sensory processing differences in autism remain poorly understood. This prospective magnetoencephalography (MEG) study investigates whether children with autism show atypical cortical activity in the primary somatosensory cortex (S1) in comparison to matched controls. Tactile stimuli were clearly detectable, painless taps applied to the distal phalanx of the second (D2) and third (D3) fingers of the right and left hands. Three tactile paradigms were administered: an oddball

  1. A cognitive neuroprosthetic that uses cortical stimulation for somatosensory feedback

    PubMed Central

    Klaes, Christian; Shi, Ying; Kellis, Spencer; Minxha, Juri; Revechkis, Boris; Andersen, Richard A.

    2015-01-01

    Present day cortical brain machine interfaces (BMI) have made impressive advances using decoded brain signals to control extracorporeal devices. Although BMIs are used in a closed-loop fashion, sensory feedback typically is visual only. However medical case studies have shown that the loss of somesthesis in a limb greatly reduces the agility of the limb even when visual feedback is available (for review see Robles-De-La-Torre, 2006). To overcome this limitation, this study tested a closed-loop BMI that utilizes intracortical microstimulation (ICMS) to provide ‘tactile’ sensation to a non-human primate (NHP). Using stimulation electrodes in Brodmann area 1 of somatosensory cortex (BA1) and recording electrodes in the anterior intraparietal area (AIP), the parietal reach region (PRR) and dorsal area 5 (area 5d), it was found that this form of feedback can be used in BMI tasks. PMID:25242377

  2. 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

  3. Decoding stimulus features in primate somatosensory cortex during perceptual categorization

    PubMed Central

    Alvarez, Manuel; Zainos, Antonio; Romo, Ranulfo

    2015-01-01

    Neurons of the primary somatosensory cortex (S1) respond as functions of frequency or amplitude of a vibrotactile stimulus. However, whether S1 neurons encode both frequency and amplitude of the vibrotactile stimulus or whether each sensory feature is encoded by separate populations of S1 neurons is not known, To further address these questions, we recorded S1 neurons while trained monkeys categorized only one sensory feature of the vibrotactile stimulus: frequency, amplitude, or duration. The results suggest a hierarchical encoding scheme in S1: from neurons that encode all sensory features of the vibrotactile stimulus to neurons that encode only one sensory feature. We hypothesize that the dynamic representation of each sensory feature in S1 might serve for further downstream processing that leads to the monkey’s psychophysical behavior observed in these tasks. PMID:25825711

  4. Behavioral detection of passive whisker stimuli requires somatosensory cortex.

    PubMed

    Miyashita, Toshio; Feldman, Daniel E

    2013-07-01

    Rodent whisker sensation occurs both actively, as whiskers move rhythmically across objects, and in a passive mode in which externally applied deflections are sensed by static, non-moving whiskers. Passive whisker stimuli are robustly encoded in the somatosensory (S1) cortex, and provide a potentially powerful means of studying cortical processing. However, whether S1 contributes to passive sensation is debated. We developed 2 new behavioral tasks to assay passive whisker sensation in freely moving rats: Detection of unilateral whisker deflections and discrimination of right versus left whisker deflections. Stimuli were simple, simultaneous multi-whisker deflections. Local muscimol inactivation of S1 reversibly and robustly abolished sensory performance on these tasks. Thus, S1 is required for the detection and discrimination of simple stimuli by passive whiskers, in addition to its known role in active whisker sensation.

  5. Automatic Parametrization of Somatosensory Evoked Potentials With Chirp Modeling.

    PubMed

    Vayrynen, Eero; Noponen, Kai; Vipin, Ashwati; Thow, X Y; Al-Nashash, Hasan; Kortelainen, Jukka; All, Angelo

    2016-09-01

    In this paper, an approach using polynomial phase chirp signals to model somatosensory evoked potentials (SEPs) is proposed. SEP waveforms are assumed as impulses undergoing group velocity dispersion while propagating along a multipath neural connection. Mathematical analysis of pulse dispersion resulting in chirp signals is performed. An automatic parameterization of SEPs is proposed using chirp models. A Particle Swarm Optimization algorithm is used to optimize the model parameters. Features describing the latencies and amplitudes of SEPs are automatically derived. A rat model is then used to evaluate the automatic parameterization of SEPs in two experimental cases, i.e., anesthesia level and spinal cord injury (SCI). Experimental results show that chirp-based model parameters and the derived SEP features are significant in describing both anesthesia level and SCI changes. The proposed automatic optimization based approach for extracting chirp parameters offers potential for detailed SEP analysis in future studies. The method implementation in Matlab technical computing language is provided online.

  6. Motor and somatosensory conversion disorder: a functional unawareness syndrome?

    PubMed

    Perez, David L; Barsky, Arthur J; Daffner, Kirk; Silbersweig, David A

    2012-01-01

    Although conversion disorder is closely connected to the origins of neurology and psychiatry, it remains poorly understood. In this article, the authors discuss neural and clinical parallels between lesional unawareness disorders and unilateral motor and somatosensory conversion disorder, emphasizing functional neuroimaging/disease correlates. Authors suggest that a functional-unawareness neurobiological framework, mediated by right hemisphere-lateralized, large-scale brain network dysfunction, may play a significant role in the neurobiology of conversion disorder. The perigenual anterior cingulate and the posterior parietal cortices are detailed as important in disease pathophysiology. Further investigations will refine the functional-unawareness concept, clarify the role of affective circuits, and delineate the process through which functional neurologic symptoms emerge.

  7. 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

  8. 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

  9. Prestimulus oscillatory power and connectivity patterns predispose conscious somatosensory perception.

    PubMed

    Weisz, Nathan; Wühle, Anja; Monittola, Gianpiero; Demarchi, Gianpaolo; Frey, Julia; Popov, Tzvetan; Braun, Christoph

    2014-01-28

    Which aspects of our sensory environment enter conscious awareness does not only depend on physical features of the stimulus, but also critically on the so-called current brain state. Results from magnetoencephalography/EEG studies using near-threshold stimuli have consistently pointed to reduced levels of α- (8-12 Hz) power in relevant sensory areas to predict whether a stimulus will be consciously perceived or not. These findings have been mainly interpreted in strictly "local" terms of enhanced excitability of neuronal ensembles in respective cortical regions. The present study aims to introduce a framework that complements this rather local perspective, by stating that the functional connectivity architecture before stimulation will predetermine information flow. Thus, information computed at a local level will be distributed throughout a network, thereby becoming consciously accessible. Data from a previously published experiment on conscious somatosensory near-threshold perception was reanalyzed focusing on the prestimulus period. Analysis of spectral power showed reduced α-power mainly in the contralateral S2 and middle frontal gyrus to precede hits, thus overall supporting the current literature. Furthermore, differences between hits and misses were obtained on global network (graph theoretical) features in the same interval. Most importantly, in accordance with our framework, we could show that the somatosensory cortex is "more efficiently" integrated into a distributed network in the prestimulus period. This finding means that when a relevant sensory stimulus impinges upon the system, it will encounter preestablished pathways for information flow. In this sense, prestimulus functional connectivity patterns form "windows" to conscious perception.

  10. MoS2 based dual input logic AND gate

    NASA Astrophysics Data System (ADS)

    Martinez, Luis M.; Pinto, Nicholas J.; Naylor, Carl H.; Johnson, A. T. Charlie

    2016-12-01

    Crystalline monolayers of CVD MoS2 are used as the active semiconducting channel in a split-gate field effect transistor. The device demonstrates logic AND functionality that is controlled by independently addressing each gate terminal with ±10V. When +10V was simultaneously applied to both gates, the device was conductive (ON), while any other combination of gate voltages rendered the device resistive (OFF). The ON/OFF ratio of the device was ˜ 35 and the charge mobility using silicon nitride as the gate dielectric was 1.2cm2/V-s and 0.1cm2/V-s in the ON and OFF states respectively. Clear discrimination between the two states was observed when a simple circuit containing a load resistor was used to test the device logic AND functionality at 10Hz. One advantage is that split gate technology can reduce the number of devices required in complex circuits, leading to compact electronics and large scale integration based on intrinsic 2-D semiconducting materials.

  11. Dermatomal Organization of SI Leg Representation in Humans: Revising the Somatosensory Homunculus.

    PubMed

    Dietrich, Caroline; Blume, Kathrin R; Franz, Marcel; Huonker, Ralph; Carl, Maria; Preißler, Sandra; Hofmann, Gunther O; Miltner, Wolfgang H R; Weiss, Thomas

    2017-01-23

    Penfield and Rasmussen's homunculus is the valid map of the neural body representation of nearly each textbook of biology, physiology, and neuroscience. The somatosensory homunculus places the foot representation on the mesial surface of the postcentral gyrus followed by the representations of the lower leg and the thigh in superio-lateral direction. However, this strong homuncular organization contradicts the "dermatomal" organization of spinal nerves. We used somatosensory-evoked magnetic fields and source analysis to study the leg's neural representation in the primary somatosensory cortex (SI). We show that the representation of the back of the thigh is located inferior to the foot's representation in SI whereas the front of the thigh is located laterally to the foot's representation. This observation indicates that the localization of the leg in SI rather follows the dermatomal organization of spinal nerves than the typical map of neighboring body parts as depicted in Penfield and Rasmussen's illustration of the somatosensory homunculus.

  12. Unanticipated Disturbance in Somatosensory Evoked Potentials in a Patient in Park-Bench Position.

    PubMed

    Babakhani, Babak; Schott, Martin; Hosseinitabatabaei, Narges; Jantzen, Jan-Peter

    2015-06-01

    Perioperative neuropathy is a known complication of malpositioning during anaesthesia. Somatosensory evoked potentials are used for detecting such a complication in selected surgeries. Most reports of intraoperative nerve injuries due to malpositioning are limited to injuries to the peripheral nervous system, and there have been no previously reported cases of somatosensory evoked potential monitoring disturbance attributable to position-related cerebral ischemia in the park-bench position. We present the case of a patient with glioblastoma in the park-bench position whose somatosensory evoked potential waveforms disappeared after head and neck repositioning. A prompt diagnosis of this complication and elimination of the underlying cause led to the return of somatosensory evoked potential waveforms, and there was no relevant neurologic deficit at the end of the surgery.

  13. 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

    2016-08-05

    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.

  14. 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

  15. Investigation of brachial plexus traction lesions by peripheral and spinal somatosensory evoked potentials.

    PubMed Central

    Jones, S J

    1979-01-01

    Peripheral, spinal and cortical somatosensory evoked potentials were recorded in 26 patients with unilateral traction injuries of the brachial plexus ganglia. Of 10 cases explored surgically the recordings correctly anticipated the major site of the lesion in eight. PMID:422958

  16. Input and Input Processing in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Alcon, Eva

    1998-01-01

    Analyzes second-language learners' processing of linguistic data within the target language, focusing on input and intake in second-language acquisition and factors and cognitive processes that affect input processing. Input factors include input simplification, input enhancement, and interactional modifications. Individual learner differences…

  17. Unattended Dual Current Monitor

    SciTech Connect

    Newell, Matthew R.; Parker, Robert F.; Jones, David C.

    2016-08-11

    The Unattended Dual Current Monitor (UDCM) is an ideal solution for current measurement needs such as ion chamber gamma measurements. The UDCM has two independent inputs and each input detects currents in two user selectable ranges, -0.2nA to -20nA or -20nA to -2uA. Measurement results can be retrieved via an Ethernet connection or by monitoring the TTL output pulses with a simple counter. Measurement data is also stored on a user accessible micro-SD card and automatically downloaded to a USB flash drive. A programmable negative High Voltage (HV) power supply provides detector bias voltages from 0 to -1,000V. The UDCM is fully compatible with the IAEA Multi Instrument Collect (MIC) software and responds to the existing MiniGRAND commands. The Ethernet port provides an IAEA RAINSTORM compliant data transfer and data security interface. The UDCM produces TTL pulses at a rate proportional to the input current, 100cps/nA. The UDCM can simplify instrumentation needs by enabling the use of a simple pulse counter for both neutron and gamma measurements. The UDCM is a simple instrument, inexpensive to manufacturer and designed for reliability.

  18. Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions.

    PubMed

    Craddock, Matt; Poliakoff, Ellen; El-Deredy, Wael; Klepousniotou, Ekaterini; Lloyd, Donna M

    2017-02-01

    Fluctuations of pre-stimulus oscillatory activity in the somatosensory alpha band (8-14Hz) observed using human EEG and MEG have been shown to influence the detection of supra- and peri-threshold somatosensory stimuli. However, some reports of touch occur even without a stimulus. We investigated the possibility that pre-stimulus alpha oscillations might also influence these false reports of touch - known as tactile misperceptions. We recorded EEG while participants performed the Somatic Signal Detection Task (SSDT), in which participants must detect brief, peri-threshold somatosensory targets. We found that pre-stimulus oscillatory power in the somatosensory alpha range exhibited a negative linear relationship with reporting of touch at electrode clusters over both contralateral and ipsilateral somatosensory regions. As pre-stimulus alpha power increased, the probability of reporting a touch declined; as it decreased, the probability of reporting a touch increased. This relationship was stronger on trials without a somatosensory stimulus than on trials with a somatosensory stimulus, although was present for both trial types. Spatio-temporal cluster-based permutation analysis also found that pre-stimulus alpha was lower on trials when touch was reported - irrespective of whether it was present - over contralateral and ipsilateral somatosensory cortices, as well as left frontocentral areas. We argue that alpha power may reflect changes in response criterion rather than sensitivity alone. Low alpha power relates to a low barrier to reporting a touch even when one is not present, while high alpha power is linked to less frequent reporting of touch overall.

  19. 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

  20. Input Decimated Ensembles

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Oza, Nikunj C.; Clancy, Daniel (Technical Monitor)

    2001-01-01

    Using an ensemble of classifiers instead of a single classifier has been shown to improve generalization performance in many pattern recognition problems. However, the extent of such improvement depends greatly on the amount of correlation among the errors of the base classifiers. Therefore, reducing those correlations while keeping the classifiers' performance levels high is an important area of research. In this article, we explore input decimation (ID), a method which selects feature subsets for their ability to discriminate among the classes and uses them to decouple the base classifiers. We provide a summary of the theoretical benefits of correlation reduction, along with results of our method on two underwater sonar data sets, three benchmarks from the Probenl/UCI repositories, and two synthetic data sets. The results indicate that input decimated ensembles (IDEs) outperform ensembles whose base classifiers use all the input features; randomly selected subsets of features; and features created using principal components analysis, on a wide range of domains.

  1. Segregation of tactile input features in neurons of the cuneate nucleus.

    PubMed

    Jörntell, Henrik; Bengtsson, Fredrik; Geborek, Pontus; Spanne, Anton; Terekhov, Alexander V; Hayward, Vincent

    2014-09-17

    Our tactile perception of external objects depends on skin-object interactions. The mechanics of contact dictates the existence of fundamental spatiotemporal input features-contact initiation and cessation, slip, and rolling contact-that originate from the fact that solid objects do not interpenetrate. However, it is unknown whether these features are represented within the brain. We used a novel haptic interface to deliver such inputs to the glabrous skin of finger/digit pads and recorded from neurons of the cuneate nucleus (the brain's first level of tactile processing) in the cat. Surprisingly, despite having similar receptive fields and response properties, each cuneate neuron responded to a unique combination of these inputs. Hence, distinct haptic input features are encoded already at subcortical processing stages. This organization maps skin-object interactions into rich representations provided to higher cortical levels and may call for a re-evaluation of our current understanding of the brain's somatosensory systems.

  2. 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.

  3. Cortex mapping of ipsilateral somatosensory area following anatomical hemispherectomy: a MEG study.

    PubMed

    Yao, Ning; Qiao, Hui; Shu, Ning; Wang, Zide; Chen, Daxing; Wu, Liang; Deng, Xiaofeng; Xu, Yulun

    2013-04-01

    A remarkable preservation of sensorimotor function is observed in patients with refractory epilepsy who were treated by hemispherectomy. Cortical regions in the remaining hemisphere or contralateral subcortical region contribute to the residual sensorimotor function. Somatosensory evoked field (SEF) is used to investigate the residual sensory function in hemispherectomized patients. The SEFs are usually recorded with magnetoencephalography (MEG). The objective is to investigate the ipsilateral cortical regions associated with residual sensory function in hemispherectomized patients using somatosensory evoked field techniques. Six patients with anatomical hemispherectomy were included. Ipsilateral and contralateral sensory functions were assessed by physical examination. Somatosensory evoked fields to electrical stimulation of the bilateral median nerves were recorded by MEG in the hemispherectomized patients and six control subjects. The stimulus intensity was adjusted to the minimum threshold that elicited a thumb twitch. The presumed neuronal source was identified as the equivalent current dipole. Six patients demonstrated different degrees of residual sensory function. Three patients had somatosensory evoked field activation in the ipsilateral cortex upon electrical stimulation of the hemiplegic hand. In these patients the locations of the ipsilateral sensorimotor cortex activation were in the primary somatosensory cortex (SI). The latency of the reliable somatosensory evoked field after stimulation of the median nerve was significantly longer for responses from the hemiplegic side compared with responses to stimulation of the median nerve from the normal side. In conclusion, ipsilateral sensory function has a time-locked relation to the cortical electromagnetic activation in the SI area of hemispherectomized patients.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25997414

  5. Sensory perception changes induced by transcranial magnetic stimulation over the primary somatosensory cortex in Parkinson's disease.

    PubMed

    Palomar, Francisco J; Díaz-Corrales, Francisco; Carrillo, Fatima; Fernández-del-Olmo, Miguel; Koch, Giacomo; Mir, Pablo

    2011-09-01

    Sensory symptoms are common nonmotor manifestations of Parkinson's disease. It has been hypothesized that abnormal central processing of sensory signals occurs in Parkinson's disease and is related to dopaminergic treatment. The objective of this study was to investigate the alterations in sensory perception induced by transcranial magnetic stimulation of the primary somatosensory cortex in patients with Parkinson's disease and the modulatory effects of dopaminergic treatment. Fourteen patients with Parkinson's disease with and without dopaminergic treatment and 13 control subjects were included. Twenty milliseconds after peripheral electrical tactile stimuli in the contralateral thumb, paired-pulse transcranial magnetic stimulation over the right primary somatosensory cortex was delivered. We evaluated the perception of peripheral electrical tactile stimuli at 2 conditioning stimulus intensities, set at 70% and 90% of the right resting motor threshold, using different interstimulus intervals. At 70% of the resting motor threshold, paired-pulse transcranial magnetic stimulation over the right primary somatosensory cortex induced an increase in positive responses at short interstimulus intervals (1-7 ms) in controls but not in patients with dopaminergic treatment. At 90% of the resting motor threshold, controls and patients showed similar transcranial magnetic stimulation effects. Changes in peripheral electrical tactile stimuli perception after paired-pulse transcranial magnetic stimulation over the primary somatosensory cortex are altered in patients with Parkinson's disease with dopaminergic treatment compared with controls. These findings suggest that primary somatosensory cortex excitability could be involved in changes in somatosensory integration in Parkinson's disease with dopaminergic treatment.

  6. 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.

  7. 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

  8. The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds

    PubMed Central

    Iwaniuk, Andrew N.; Castro, Isabel; Alley, Maurice R.; Birkhead, Tim R.; Parsons, Stuart

    2013-01-01

    Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These ‘bill-tip organs’ allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill

  9. The anatomy of the bill tip of kiwi and associated somatosensory regions of the brain: comparisons with shorebirds.

    PubMed

    Cunningham, Susan J; Corfield, Jeremy R; Iwaniuk, Andrew N; Castro, Isabel; Alley, Maurice R; Birkhead, Tim R; Parsons, Stuart

    2013-01-01

    Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These 'bill-tip organs' allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill

  10. Adaptation of the cortical somatosensory evoked potential following pulsed pneumatic stimulation of the lower face in adults.

    PubMed

    Custead, Rebecca; Oh, Hyuntaek; Rosner, Austin Oder; Barlow, Steven

    2015-10-05

    Cortical adaptation to sustained sensory input is a pervasive form of short-term plasticity in neurological systems. Its role in sensory perception in health and disease, or predicting long-term plastic changes resulting from sensory training offers insight into the mechanisms of somatosensory and sensorimotor processing. A 4-channel electroencephalography (EEG) recording montage was placed bilaterally (C3-P3, C4-P4, F7-P3, F8-P4) to characterize the short-term effects of pulsed pneumatic orofacial stimulation on the cortical somatosensory evoked potential (cSEP) in twenty neurotypical adults (mean age=21±2.88 years). A servo-controlled pneumatic amplifier was used to deliver a repetitive series of pneumatic pulse trains (six 50-ms pulses, 5-second intertrain interval) through a linked pair of custom acetal homopolymer probes (aka TAC-Cells) adhered to the nonglabrous skin of the lower face proximal to the right oral angle to synchronously activate mechanoreceptive afferents in the trigeminal nerve. Blocks of pulse trains were counterbalanced among participants and delivered at two rates, 2 and 4Hz. TAC-Cell stimulation of the lower face consistently evoked a series of cSEPs at P7, N20, P28, N38, P75, N85, and P115. The spatial organization and adaptation of the evoked cSEP was dependent on stimulus pulse index (1-6 within the pulse train, p=.012), frequency of stimulus presentation (2 vs 4Hz, p<.001), component (P7-P115, p<.001), and recording montage (channels 1-4, p<.001). Early component latencies (P7-N20) were highly stable in polarity (sign) and latency, and consistent with putative far-field generators (e.g., trigeminal brainstem, ventroposteromedial thalamus).

  11. Cutaneous and periodontal inputs to the cerebellum of the naked mole-rat (Heterocephalus glaber).

    PubMed

    Sarko, Diana K; Leitch, Duncan B; Catania, Kenneth C

    2013-01-01

    The naked mole-rat (Heterocephalus glaber) is a small fossorial rodent with specialized dentition that is reflected by the large cortical area dedicated to representation of the prominent incisors. Due to naked mole-rats' behavioral reliance on the incisors for digging and for manipulating objects, as well as their ability to move the lower incisors independently, we hypothesized that expanded somatosensory representations of the incisors would be present within the cerebellum in order to accommodate a greater degree of proprioceptive, cutaneous, and periodontal input. Multiunit electrophysiological recordings targeting the ansiform lobule were used to investigate tactile inputs from receptive fields on the entire body with a focus on the incisors. Similar to other rodents, a fractured somatotopy appeared to be present with discrete representations of the same receptive fields repeated within each folium of the cerebellum. These findings confirm the presence of somatosensory inputs to a large area of the naked mole-rat cerebellum with particularly extensive representations of the lower incisors and mystacial vibrissae. We speculate that these extensive inputs facilitate processing of tactile cues as part of a sensorimotor integration network that optimizes how sensory stimuli are acquired through active exploration and in turn adjusts motor outputs (such as independent movement of the lower incisors). These results highlight the diverse sensory specializations and corresponding brain organizational schemes that have evolved in different mammals to facilitate exploration of and interaction with their environment.

  12. Tactile impoverishment and sensorimotor restriction deteriorate the forepaw cutaneous map in the primary somatosensory cortex of adult rats.

    PubMed

    Coq, J O; Xerri, C

    1999-12-01

    We investigated the effects of sensory deprivation on the forepaw representation in the primary somatosensory cortex (SI) in the adult rat. Cortical maps were constructed from high-resolution multiunit recordings of the response of layer IV neurons to somatosensory stimuli. The main features of the forepaw representation were described in terms of areal extent and topography of the cortical map, and sensory submodality, size, and location of the receptive field (RF) of small clusters of the cortical neurons. After being weaned, two groups of Long-Evans rats were housed in a standard (SE) or impoverished (IE) environment for 65-115 days. A third group of SE rats was subjected to severe sensorimotor restriction (SR) of one forepaw for 7 days or 14 days, by using a one-sleeved cast. A concomitant effect of unilateral forelimb immobilization was a forced use of the nonrestricted forelimb in postural balance. The maps of both forepaws were derived 24 h after the cast was removed and the animal was allowed normal limb use. In a fourth group, SE rats experienced a 7-day immobilization followed by symmetrical limb use for 7 days before we mapped the hemisphere contralateral to the casted limb. For the SE and IE rats, the total areal extent of the cutaneous forepaw representation was similar, but IE rats exhibited a significant expansion of cortical islets serving high-threshold, presumably noncutaneous inputs, which were included in the cutaneous maps. In addition, SI neurons of IE rats had greatly enlarged glabrous, but not hairy, skin RFs. For the SR rats, the areal extent of the cutaneous map of the casted forepaw decreased by about 50%, after both 7- and 14-day forelimb immobilization. Large cortical sectors presumed to be formerly activated by cutaneous inputs were driven by high-threshold inputs that disrupted the somatotopic representation of the forepaw skin surfaces. These "emergent" representational sectors were topographically organized. By contrast, the areal

  13. Subcortical interactions between somatosensory stimuli of different modalities and their temporal profile.

    PubMed

    Costa, João; Valls-Solé, Josep; Valldeoriola, Francesc; Rumià, Jordi

    2008-09-01

    Interactions between inputs of different sensory modality occur along the sensory pathway, including the thalamus. However, the temporal profile of such interaction has not been fully studied. In eight patients who had been implanted an intrathalamic electrode for deep brain stimulation as symptomatic treatment of tremor, we investigated the interactions between mechanical taps and electrical nerve stimuli. Somatosensory evoked potentials (SEPs) were recorded from Erb's point, cervical spinal cord, nucleus ventrointermedialis of the thalamus, and parietal cortex. A handheld electronic reflex hammer was used to deliver a mechanical tap to the skin overlying the first dorsal interosseous muscle and to trigger an ipsilateral digital median nerve electrical stimulus time-locked to the mechanical tap with a variable delay of 0 to 50 ms. There were significant time-dependent interactions between the two sensory volleys at the subcortical level. Thalamic SEPs were decreased in amplitude at interstimulus intervals (ISIs) from 10 to 40 ms with maximum effect at 20 ms (-42.8 +/- 10.5%; P < 0.001). A similar decrease was also seen in the number and frequency of the high-frequency components of thalamic SEPs (-25 +/- 4%). A smaller reduction (-18.1 +/- 5.8%; P < 0.001) was present in upper cervical response at ISI = 20 ms. There were no changes in peripheral responses. Cortical SEPs were almost completely absent in some subjects at ISIs from 20 to 50 ms. There were no changes in SEP latencies. Our results indicate that significant time-dependent interactions between sensory volleys occur at the subcortical level. These observations provide further insight into the physiological mechanisms underlying afferent gating between sensory volleys of different modality.

  14. Neuronal activity in somatosensory cortex related to tactile exploration.

    PubMed

    Fortier-Poisson, Pascal; Smith, Allan M

    2016-01-01

    The very light contact forces (∼0.60 N) applied by the fingertips during tactile exploration reveal a clearly optimized sensorimotor strategy. To investigate the cortical mechanisms involved with this behavior, we recorded 230 neurons in the somatosensory cortex (S1), as two monkeys scanned different surfaces with the fingertips in search of a tactile target without visual feedback. During the exploration, the monkeys, like humans, carefully controlled the finger forces. High-friction surfaces offering greater tangential shear force resistance to the skin were associated with decreased normal contact forces. The activity of one group of neurons was modulated with either the normal or tangential force, with little or no influence from the orthogonal force component. A second group responded to kinetic friction or the ratio of tangential to normal forces rather than responding to a specific parameter, such as force magnitude or direction. A third group of S1 neurons appeared to respond to particular vectors of normal and tangential force on the skin. Although 45 neurons correlated with scanning speed, 32 were also modulated by finger forces, suggesting that forces on the finger should be considered as the primary parameter encoding the skin compliance and that finger speed is a secondary parameter that co-varies with finger forces. Neurons (102) were also tested with different textures, and the activity of 62 of these increased or decreased in relation to the surface friction.

  15. An Intelligent Decision System for Intraoperative Somatosensory Evoked Potential Monitoring.

    PubMed

    Fan, Bi; Li, Han-Xiong; Hu, Yong

    2016-02-01

    Somatosensory evoked potential (SEP) is a useful, noninvasive technique widely used for spinal cord monitoring during surgery. One of the main indicators of a spinal cord injury is the drop in amplitude of the SEP signal in comparison to the nominal baseline that is assumed to be constant during the surgery. However, in practice, the real-time baseline is not constant and may vary during the operation due to nonsurgical factors, such as blood pressure, anaesthesia, etc. Thus, a false warning is often generated if the nominal baseline is used for SEP monitoring. In current practice, human experts must be used to prevent this false warning. However, these well-trained human experts are expensive and may not be reliable and consistent due to various reasons like fatigue and emotion. In this paper, an intelligent decision system is proposed to improve SEP monitoring. First, the least squares support vector regression and multi-support vector regression models are trained to construct the dynamic baseline from historical data. Then a control chart is applied to detect abnormalities during surgery. The effectiveness of the intelligent decision system is evaluated by comparing its performance against the nominal baseline model by using the real experimental datasets derived from clinical conditions.

  16. [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).

  17. Feeling Touched: Emotional Modulation of Somatosensory Potentials to Interpersonal Touch.

    PubMed

    Ravaja, N; Harjunen, V; Ahmed, I; Jacucci, G; Spapé, M M

    2017-01-12

    Although the previous studies have shown that an emotional context may alter touch processing, it is not clear how visual contextual information modulates the sensory signals, and at what levels does this modulation take place. Therefore, we investigated how a toucher's emotional expressions (anger, happiness, fear, and sadness) modulate touchee's somatosensory-evoked potentials (SEPs) in different temporal ranges. Participants were presented with tactile stimulation appearing to originate from expressive characters in virtual reality. Touch processing was indexed using SEPs, and self-reports of touch experience were collected. Early potentials were found to be amplified after angry, happy and sad facial expressions, while late potentials were amplified after anger but attenuated after happiness. These effects were related to two stages of emotional modulation of tactile perception: anticipation and interpretation. The findings show that not only does touch affect emotion, but also emotional expressions affect touch perception. The affective modulation of touch was initially obtained as early as 25 ms after the touch onset suggesting that emotional context is integrated to the tactile sensation at a very early stage.

  18. Dodecapus: An MR-compatible system for somatosensory stimulation.

    PubMed

    Huang, Ruey-Song; Sereno, Martin I

    2007-02-01

    Somatotopic mapping of human body surface using fMRI is challenging. First, it is difficult to deliver tactile stimuli in the scanner. Second, multiple stimulators are often required to cover enough area of the complex-shaped body surface, such as the face. In this study, a computer-controlled pneumatic system was constructed to automatically deliver air puffs to 12 locations on the body surface through an MR-compatible manifold (Dodecapus) mounted on a head coil inside the scanner bore. The timing of each air-puff channel is completely programmable and this allows systematic and precise stimulation on multiple locations on the body surface during functional scans. Three two-condition block-design "Localizer" paradigms were employed to localize the cortical representations of the face, lips, and fingers, respectively. Three "Phase-encoded" paradigms were employed to map the detailed somatotopic organizations of the face, lips, and fingers following each "Localizer" paradigm. Multiple somatotopic representations of the face, lips, and fingers were localized and mapped in primary motor cortex (MI), ventral premotor cortex (PMv), polysensory zone (PZ), primary (SI) and secondary (SII) somatosensory cortex, parietal ventral area (PV) and 7b, as well as anterior and ventral intraparietal areas (AIP and VIP). The Dodecapus system is portable, easy to setup, generates no radio frequency interference, and can also be used for EEG and MEG experiments. This system could be useful for non-invasive somatotopic mapping in both basic and clinical studies.

  19. 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

  20. Subthalamic stimulation influences postmovement cortical somatosensory processing in Parkinson's disease.

    PubMed

    Devos, D; Labyt, E; Cassim, F; Bourriez, J L; Reyns, N; Touzet, G; Blond, S; Guieu, J D; Derambure, P; Destée, A; Defebvre, L

    2003-10-01

    In Parkinson's disease, poor motor performance (resulting primarily from abnormal cortical activation during movement preparation and execution) may also be due to impaired sensorimotor integration and defective cortical activity termination of the ongoing movement, thus delaying preparation of the following one. Reduced movement-related synchronization of the beta rhythm in Parkinson's disease compared to controls has been put forward as evidence for impaired postmovement cortical deactivation. We assessed the effects of subthalamic deep brain stimulation and l-dopa on beta rhythm synchronization over the premotor and primary sensorimotor cortex. Ten advanced patients performed self-paced wrist flexion in four conditions according to the presence or not of stimulation and l-dopa. Compared to without treatment, the motor score improved by approximately 60%; the beta synchronization was present over the contralateral frontocentral region and increased significantly over the contralateral central region under stimulation and under l-dopa, with a maximal effect when both treatments were associated. Our advanced patients displayed very focused and attenuated beta rhythm synchronization which, under stimulation, increased over the contralateral premotor and primary sensorimotor cortex. Stimulation and l-dopa both partly restored postmovement cortical deactivation in advanced Parkinson's disease, although the respective mechanisms probably differ. They may improve bradykinesia and cortical deactivation by reestablishing movement-related somatosensory processing at the end of the movement through the basal ganglia into the cortex.

  1. Neuronal correlates of sensory discrimination in the somatosensory cortex

    PubMed Central

    Hernández, Adrián; Zainos, Antonio; Romo, Ranulfo

    2000-01-01

    Monkeys are able to discriminate the difference in frequency between two periodic mechanical vibrations applied sequentially to the fingertips. It has been proposed that this ability is mediated by the periodicity of the responses in the quickly adapting (QA) neurons of the primary somatosensory cortex (S1), instead of the average firing rates. We recorded from QA neurons of S1 while monkeys performed the vibrotactile discrimination task. We found that the periodic mechanical vibrations can be represented both in the periodicity and in the firing rate responses to varying degrees across the QA neuronal population. We then computed neurometric functions by using both the periodicity and the firing rate and sought to determine which of these two measures is associated with the psychophysical performance. We found that neurometric thresholds based on the firing rate are very similar to the animal's psychometric thresholds whereas neurometric thresholds based on periodicity are far lower than those thresholds. These results indicate that an observer could solve this task with a precision similar to that of the monkey, based only on the firing rate produced during the stimulus periods. PMID:10811922

  2. Feeling Touched: Emotional Modulation of Somatosensory Potentials to Interpersonal Touch

    PubMed Central

    Ravaja, N.; Harjunen, V.; Ahmed, I.; Jacucci, G.; Spapé, M. M.

    2017-01-01

    Although the previous studies have shown that an emotional context may alter touch processing, it is not clear how visual contextual information modulates the sensory signals, and at what levels does this modulation take place. Therefore, we investigated how a toucher’s emotional expressions (anger, happiness, fear, and sadness) modulate touchee’s somatosensory-evoked potentials (SEPs) in different temporal ranges. Participants were presented with tactile stimulation appearing to originate from expressive characters in virtual reality. Touch processing was indexed using SEPs, and self-reports of touch experience were collected. Early potentials were found to be amplified after angry, happy and sad facial expressions, while late potentials were amplified after anger but attenuated after happiness. These effects were related to two stages of emotional modulation of tactile perception: anticipation and interpretation. The findings show that not only does touch affect emotion, but also emotional expressions affect touch perception. The affective modulation of touch was initially obtained as early as 25 ms after the touch onset suggesting that emotional context is integrated to the tactile sensation at a very early stage. PMID:28079157

  3. Neuronal activity in somatosensory cortex related to tactile exploration

    PubMed Central

    Fortier-Poisson, Pascal

    2015-01-01

    The very light contact forces (∼0.60 N) applied by the fingertips during tactile exploration reveal a clearly optimized sensorimotor strategy. To investigate the cortical mechanisms involved with this behavior, we recorded 230 neurons in the somatosensory cortex (S1), as two monkeys scanned different surfaces with the fingertips in search of a tactile target without visual feedback. During the exploration, the monkeys, like humans, carefully controlled the finger forces. High-friction surfaces offering greater tangential shear force resistance to the skin were associated with decreased normal contact forces. The activity of one group of neurons was modulated with either the normal or tangential force, with little or no influence from the orthogonal force component. A second group responded to kinetic friction or the ratio of tangential to normal forces rather than responding to a specific parameter, such as force magnitude or direction. A third group of S1 neurons appeared to respond to particular vectors of normal and tangential force on the skin. Although 45 neurons correlated with scanning speed, 32 were also modulated by finger forces, suggesting that forces on the finger should be considered as the primary parameter encoding the skin compliance and that finger speed is a secondary parameter that co-varies with finger forces. Neurons (102) were also tested with different textures, and the activity of 62 of these increased or decreased in relation to the surface friction. PMID:26467519

  4. Ontogeny of somatostatin receptors in the rat somatosensory cortex

    SciTech Connect

    Gonzalez, B.J.; Leroux, P.; Bodenant, C.; Vaudry, H. )

    1991-03-08

    The distribution and density of SRIF receptors (SRIF-R) were studied during development in the rat somatosensory cortex by in vitro autoradiography with monoiodinated (Tyr0-DTrp8)S14. In 16-day-old fetuses (E16), intense labeling was evident in the intermediate zone of the cortex while low concentrations of SRIF-R were detected in the marginal and ventricular zones. The highest density of SRIF-R was measured in the intermediate zone at E18. At this stage, labeling was also intense in the internal part of the developing cortical plate; in contrast, the concentration of binding sites associated with the marginal and ventricular zones remained relatively low. Profound modifications in the distribution of SRIF-R appeared at birth. In particular, a transient reduction of receptor density occurred in the cortical plate. During the first postnatal week, the density of receptors measured in the intermediate zone decreased gradually; conversely, high levels of SRIF-R were observed in the developing cortical layers (II to VI). At postpartum day 13 (P13), a stage which just precedes completion of cell migration in the parietal cortex, the most intensely labeled regions were layers V-VI and future layers II-III. From P13 to adulthood, the concentrations of SRIF-R decreased in all cortical layers (I to VI) and the pattern of distribution of receptors at P21 was similar to that observed in the adults.

  5. Dual Brushless Resolver Rate Sensor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor)

    1997-01-01

    A resolver rate sensor is disclosed in which dual brushless resolvers are mechanically coupled to the same output shaft. Diverse inputs are provided to each resolver by providing the first resolver with a DC input and the second resolver with an AC sinusoidal input. A trigonometric identity in which the sum of the squares of the sin and cosine components equal one is used to advantage in providing a sensor of increased accuracy. The first resolver may have a fixed or variable DC input to permit dynamic adjustment of resolver sensitivity thus permitting a wide range of coverage. In one embodiment of the invention the outputs of the first resolver are directly inputted into two separate multipliers and the outputs of the second resolver are inputted into the two separate multipliers, after being demodulated in a pair of demodulator circuits. The multiplied signals are then added in an adder circuit to provide a directional sensitive output. In another embodiment the outputs from the first resolver is modulated in separate modulator circuits and the output from the modulator circuits are used to excite the second resolver. The outputs from the second resolver are demodulated in separate demodulator circuit and added in an adder circuit to provide a direction sensitive rate output.

  6. Cortical hyperexcitability in response to preserved spinothalamic inputs immediately after spinal cord hemisection.

    PubMed

    Yague, J G; Foffani, G; Aguilar, J

    2011-02-01

    Chronic injury of the main somatosensory pathways ascending along the spinal cord - the dorsal columns and the spinothalamic tract - can produce both changes in the organization of cortical somatotopic maps and neuropathic pain. Little is known, however, about the early neurophysiological changes occurring immediately after injury. We bilaterally recorded the neural activity of the hindpaw representation of the primary somatosensory cortex evoked by stimuli delivered to the hindpaws before and immediately after a thoracic spinal cord hemisection in anesthetized rats. This unilateral spinal cord injury allowed us to separately investigate the cortical effects of deafferenting the dorsal column (stimuli ipsilateral to the hemisection) or the spinothalamic tract (stimuli contralateral to the hemisection). The hemisection produced immediate bilateral changes in the cortical responses evoked by stimuli delivered to the hindpaw ipsilateral to the hemisection (deafferented dorsal column): an expected loss of classical short-latency cortical responses, accompanied by an unexpected appearance of long-latency activations. At the population level, these activations reflected a progressive stimulus-induced transition of the hindpaw somatosensory cortex from up-and-down states to a sustained activated state. At the single-cell level, these cortical activations resembled the "wind-up" typically observed - with the same type of stimuli - in the dorsal horn cells originating the spinothalamic tract. Virtually no changes were observed in the responses evoked by stimuli delivered to the hindpaw contralateral to the hemisection (deafferented spinothalamic tract). These results suggest that spinal cord hemisection immediately produces an abnormal hyperexcitability of the primary somatosensory cortex in response to preserved spinothalamic inputs from the hindpaw. This immediate cortical hyperexcitability could be important to understand the long-term development of cortical

  7. Facilitation of cutaneous inputs during the planning phase of gait initiation

    PubMed Central

    Fontan, Aurélie; Tandonnet, Christophe; Perrier, Joy; Saradjian, Anahid H.; Blouin, Jean; Simoneau, Martin

    2015-01-01

    It has been shown that during the planning of a voluntary movement the transmission of cutaneous afferent inputs to the somatosensory cortex is attenuated shortly before the motor output as well as during movement execution. However, it is not known whether the sensory suppression observed during the planning phase (i.e., before any movement execution) is a systemic phenomenon or whether it is dependent on movement context. For example, movements such as step initiation are controlled based on information received from cutaneous receptors in the feet. Because afferent information emerging from these receptors is critical for movement initiation, we hypothesized that suppression of these inputs may not occur during the planning phase prior to gait initiation. To examine this hypothesis we measured the cortical response to somatosensory stimulation during the planning phase of step initiation and during movement execution. Sensitivity to cutaneous stimulation was assessed by measuring the amplitude of the cortical somatosensory-evoked potential (SEP, over the Cz electrode) following electrical stimulations of the plantar sole of one foot. Two stimulations were provided during the planning phase of a step movement and two stimulations during movement execution. It was found that the P50-N80 SEP was facilitated in the early planning phase (−700 ms before motor execution) compared with when participants remained still (control standing task). This mechanism might contribute to an enhanced perception of cutaneous input leading to a more accurate setting of the forces to be exerted onto the ground to shift the body's weight toward the supporting side prior to foot-off. PMID:25925329

  8. 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.

  9. Sensory gating, inhibition control and gamma oscillations in the human somatosensory cortex.

    PubMed

    Cheng, Chia-Hsiung; Chan, Pei-Ying S; Niddam, David M; Tsai, Shang-Yueh; Hsu, Shih-Chieh; Liu, Chia-Yih

    2016-02-04

    Inhibiting the responses to irrelevant stimuli is an essential component of human cognitive function. Pre-attentive auditory sensory gating (SG), an attenuated neural activation to the second identical stimulus, has been found to be related to the performance of higher-hierarchical brain function. However, it remains unclear whether other cortical regions, such as somatosensory cortex, also possess similar characteristics, or if such a relationship is modality-specific. This study used magnetoencephalography to record neuromagnetic responses to paired-pulse electrical stimulation to median nerve in 22 healthy participants. Somatosensory SG ratio and cortical brain oscillations were obtained and compared with the behavioral performance of inhibition control, as evaluated by somatosensory and auditory Go-Nogo tasks. The results showed that somatosensory P35m SG ratio correlated with behavioral performance of inhibition control. Such relationship was also established in relation to the auditory Go-Nogo task. Finally, a higher frequency value of evoked gamma oscillations was found to relate to a better somatosensory SG ability. In conclusion, our data provided an empirical link between automatic cortical inhibition and behavioral performance of attentive inhibition control. This study invites further research on the relationships among gamma oscillations, neurophysiological indices, and behavioral performance in clinical populations in terms of SG or cortical inhibition.

  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.

  11. Regularity of approaching visual stimuli influences spatial expectations for subsequent somatosensory stimuli.

    PubMed

    Kimura, Tsukasa; Katayama, Jun'ichi

    2017-03-07

    This study examines how the regularity of visual stimuli approaching the body influences spatial expectations of subsequent somatosensory stimuli by recording event-related brain potentials (ERPs) during a simple reaction time (RT) task involving responses to somatosensory stimuli. Twenty-one participants were instructed to put their arms on a desk, and three LEDs were placed equidistantly between their arms. Electrical stimuli were presented with a high probability (80%) of being applied to one wrist and a low probability (20%) of being applied to the opposite wrist. One trial was composed of three visual stimuli followed by one electrical stimulus. In the regular approach condition, LEDs flashed sequentially toward the wrist with the high-probability somatosensory stimulus. In the irregular approach condition, the first and second visual stimuli were presented randomly, but the third visual stimulus was invariably presented near the wrist with the high-probability stimulus. In both conditions, RTs for low-probability stimuli were slower than those for high-probability stimuli, and the low-probability stimuli elicited larger P3 amplitudes than the high-probability stimuli. Furthermore, the largest P3 amplitude was elicited by low-probability stimuli under the regular approach condition, whereas the amplitudes of contingent negative variation (CNV) elicited before the presentation of the somatosensory stimuli did not differ between conditions. These results indicate that regularity of visual stimuli approaching the body facilitates an automatic spatial expectation for subsequent somatosensory stimuli.

  12. Sustained attention to spontaneous thumb sensations activates brain somatosensory and other proprioceptive areas.

    PubMed

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

    2014-06-01

    The present experiment was designed to test if sustained attention directed to the spontaneous sensations of the right or left thumb in the absence of any external stimuli is able to activate corresponding somatosensory brain areas. After verifying in 34 healthy volunteers that external touch stimuli to either thumb effectively activate brain contralateral somatosensory areas, and after subtracting attention mechanisms employed in both touch and spontaneous-sensation conditions, fMRI evidence was obtained that the primary somatosensory cortex (specifically left BA 3a/3b) becomes active when an individual is required to attend to the spontaneous sensations of either thumb in the absence of external stimuli. In addition, the left superior parietal cortex, anterior cingulate gyrus, insula, motor and premotor cortex, left dorsolateral prefrontal cortex, Broca's area, and occipital cortices were activated. Moreover, attention to spontaneous-sensations revealed an increased connectivity between BA 3a/3b, superior frontal gyrus (BA 9) and anterior cingulate cortex (BA 32), probably allowing top-down activations of primary somatosensory cortex. We conclude that specific primary somatosensory areas in conjunction with other left parieto-frontal areas are involved in processing proprioceptive and interoceptive bodily information that underlies own body-representations and that these networks and cognitive functions can be modulated by top-down attentional processes.

  13. 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.

  14. fMRI investigation of unexpected somatosensory feedback perturbation during speech.

    PubMed

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

    2011-04-01

    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.

  15. Sensory gating, inhibition control and gamma oscillations in the human somatosensory cortex

    PubMed Central

    Cheng, Chia-Hsiung; Chan, Pei-Ying S.; Niddam, David M.; Tsai, Shang-Yueh; Hsu, Shih-Chieh; Liu, Chia-Yih

    2016-01-01

    Inhibiting the responses to irrelevant stimuli is an essential component of human cognitive function. Pre-attentive auditory sensory gating (SG), an attenuated neural activation to the second identical stimulus, has been found to be related to the performance of higher-hierarchical brain function. However, it remains unclear whether other cortical regions, such as somatosensory cortex, also possess similar characteristics, or if such a relationship is modality-specific. This study used magnetoencephalography to record neuromagnetic responses to paired-pulse electrical stimulation to median nerve in 22 healthy participants. Somatosensory SG ratio and cortical brain oscillations were obtained and compared with the behavioral performance of inhibition control, as evaluated by somatosensory and auditory Go-Nogo tasks. The results showed that somatosensory P35m SG ratio correlated with behavioral performance of inhibition control. Such relationship was also established in relation to the auditory Go-Nogo task. Finally, a higher frequency value of evoked gamma oscillations was found to relate to a better somatosensory SG ability. In conclusion, our data provided an empirical link between automatic cortical inhibition and behavioral performance of attentive inhibition control. This study invites further research on the relationships among gamma oscillations, neurophysiological indices, and behavioral performance in clinical populations in terms of SG or cortical inhibition. PMID:26843358

  16. 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.

  17. Position and velocity coupling of postural sway to somatosensory drive.

    PubMed

    Jeka, J; Oie, K; Schöner, G; Dijkstra, T; Henson, E

    1998-04-01

    Light touch contact of a fingertip to a stationary surface provides orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip lead to sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, the coupling of postural sway to a moving contact surface was investigated in detail. Head, center of mass, and center of pressure displacement were measured as the contact surface moved rhythmically at 0.1, 0.2, 0.4, 0.6, and 0.8 Hz. Stimulus amplitude decreased with frequency to maintain peak velocity constant across frequency. Head and body sway were highly coherent with contact surface motion at all frequencies except 0.8 Hz, where a drop-off in coherence was observed. Mean frequency of head and body sway matched the driving frequency somatosensory system.

  18. Neurodegeneration in the somatosensory cortex after experimental diffuse brain injury

    PubMed Central

    Lisembee, Amanda M.

    2012-01-01

    Disruption and consequent reorganization of central nervous system circuits following traumatic brain injury may manifest as functional deficits and behavioral morbidities. We previously reported axotomy and neuronal atrophy in the ventral basal (VB) complex of the thalamus, without gross degeneration after experimental diffuse brain injury in adult rats. Pathology in VB coincided with the development of late-onset aberrant behavioral responses to whisker stimulation, which lead to the current hypothesis that neurodegeneration after experimental diffuse brain injury includes the primary somatosensory barrel cortex (S1BF), which receives projection of VB neurons and mediates whisker somatosensation. Over 28 days after midline fluid percussion brain injury, argyrophilic reaction product within superficial layers and layer IV barrels at 1 day progresses into the cortex to subcortical white matter by 7 days, and selective inter-barrel septa and subcortical white matter labeling at 28 days. Cellular consequences were determined by stereological estimates of neuronal nuclear volumes and number. In all cortical layers, neuronal nuclear volumes significantly atrophied by 42–49% at 7 days compared to sham, which marginally attenuated by 28 days. Concomitantly, the number of healthy neurons was reduced by 34–45% at 7 days compared to sham, returning to control levels by 28 days. Progressive neurodegeneration, including argyrophilic reaction product and neuronal nuclear atrophy, indicates injury-induced damage and reorganization of the reciprocal thalamocortical projections that mediate whisker somatosensation. The rodent whisker barrel circuit may serve as a discrete model to evaluate the causes and consequences of circuit reorganization after diffuse brain injury. PMID:21597967

  19. Somatosensory-evoked blink response: investigation of the physiological mechanisms.

    PubMed

    Miwa, H; Nohara, C; Hotta, M; Shimo, Y; Amemiya, K

    1998-02-01

    The somatosensory-evoked blink response (SBR) is a newly identified blink reflex elicited by electrical stimulation of peripheral nerves. The present study was performed to investigate the physiological mechanism underlying the SBR elicited by median nerve stimulation in normal subjects. The peripheral afferents responsible for the SBR included low-threshold cutaneous fibres. In the SBR-positive subjects, the late (R2) component of the blink reflex elicited by supraorbital nerve stimulation and the SBR facilitated each other when both responses were induced at the same time, but they each caused long-lasting inhibition in the other when one stimulus was given as a conditioning stimulus. The extent of inhibition was correlated with the size of the preceding SBR. In the SBR-negative subjects, simultaneous inhibition of R2 was observed when median nerve stimulation was applied as a conditioning stimulus. Brainstem excitability, as evaluated by blink-reflex recovery studies, did not differ between SBR-positive and SBR-negative subjects. Therefore, based on anatomical and physiological findings, it appears that the reflex pathways of the SBR and R2 converge within the brainstem and compete with each other, presumably by presynaptic inhibition at the premotor level, before entering the common blink-reflex pathway. The influence of median nerve stimulation upon tonic contraction of the orbicularis oculi muscle was studied to detect the latent SBR. There was not only a facilitatory period corresponding to the SBR but also an active inhibitory period (exteroceptive suppression), suggesting that the mechanism generating the SBR is not only influenced by blink-reflex volleys but also by active exteroceptive suppression. Thus, the SBR may appear as a result of integration of facilitatory and inhibitory mechanisms within the brainstem.

  20. 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.

  1. Decoding temporally encoded sensory input by cortical oscillations and thalamic phase comparators.

    PubMed

    Ahissar, E; Haidarliu, S; Zacksenhouse, M

    1997-10-14

    The temporally encoded information obtained by vibrissal touch could be decoded "passively," involving only input-driven elements, or "actively," utilizing intrinsically driven oscillators. A previous study suggested that the trigeminal somatosensory system of rats does not obey the bottom-up order of activation predicted by passive decoding. Thus, we have tested whether this system obeys the predictions of active decoding. We have studied cortical single units in the somatosensory cortices of anesthetized rats and guinea pigs and found that about a quarter of them exhibit clear spontaneous oscillations, many of them around whisking frequencies ( approximately 10 Hz). The frequencies of these oscillations could be controlled locally by glutamate. These oscillations could be forced to track the frequency of induced rhythmic whisker movements at a stable, frequency-dependent, phase difference. During these stimulations, the response intensities of multiunits at the thalamic recipient layers of the cortex decreased, and their latencies increased, with increasing input frequency. These observations are consistent with thalamocortical loops implementing phase-locked loops, circuits that are most efficient in decoding temporally encoded information like that obtained by active vibrissal touch. According to this model, and consistent with our results, populations of thalamic "relay" neurons function as phase "comparators" that compare cortical timing expectations with the actual input timing and represent the difference by their population output rate.

  2. Reticular thalamic responses to nociceptive inputs in anesthetized rats.

    PubMed

    Yen, Chen-Tung; Shaw, Fu-Zen

    2003-04-11

    The present study compares nociceptive responses of neurons in the reticular thalamic nucleus (RT) to those of the ventroposterior lateral nucleus (VPL). Extracellular single-unit activities of cells in the RT and VPL were recorded in anesthetized rats. Only units with identified tactile receptive fields in the forepaw or hindpaw were studied. In the first series of experiments, RT and VPL responses to pinching with a small artery clamp were tested with the rats under pentobarbital, urethane, ketamine, or halothane anesthesia. Under all types of anesthesia, many RT units were inhibited. Second, the specificity of the nociceptive response was tested by pinching and noxious heating of the unit's tactile receptive field. Of the 39 VPL units tested, 20 were excited by both types of noxious stimuli. In sharp contrast, of the 30 RT units tested, none were excited and 17 were inhibited. In a third series of experiments, low-intensity and beam-diffused CO(2) laser irradiation was used to activate peripheral nociceptive afferents. Wide-dynamic-range VPL units responded with short- and long-latency excitations. In contrast, RT units had short-latency excitation followed by long-latency inhibition. Nociceptive input inhibited RT units in less than 500 ms. We conclude that a significant portion of RT neurons were polysynaptically inhibited by nociceptive inputs. Since all the cells tested were excited by light tactile inputs, the somatosensory RT may serve in the role of a modality gate, which modifies (i.e. inhibits) tactile inputs while letting noxious inputs pass.

  3. [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

  4. 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.

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

    SciTech Connect

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

    1990-07-01

    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.

  6. Lack of activation of human secondary somatosensory cortex in Unverricht-Lundborg type of progressive myoclonus epilepsy.

    PubMed

    Forss, N; Silén, T; Karjalainen, T

    2001-01-01

    Previous electroencephalographic and magnetoencephalographic studies have demonstrated giant early somatosensory cortical responses in patients with cortical myoclonus. We applied whole-scalp magnetoencephalography to study activation sequences of the somatosensory cortical network in 7 patients with Unverricht-Lundborg-type progressive myoclonus epilepsy diagnostically verified by DNA analysis. Responses to electric median nerve stimuli displayed 30-msec peaks at the contralateral primary somatosensory cortex that were four times stronger in patients than in control subjects. The amplitudes of 20-msec responses did not significantly differ between the groups. In contrast to control subjects, 5 patients displayed ipsilateral primary somatosensory cortex activity at 48 to 61 msec in response to both left- and right-sided median nerve stimuli. Furthermore, their secondary somatosensory cortex was not significantly activated. These abnormalities indicate altered responsiveness of the entire somatosensory cortical network outside the contralateral primary somatosensory cortex in patients with Unverricht-Lundborg-type progressive myoclonus epilepsy. The deficient activation of the secondary somatosensory cortex in Unverricht-Lundborg patients may reflect disturbed sensorimotor integration, probably related to impaired movement coordination.

  7. 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…

  8. Effects of repetitive transcranial magnetic stimulation on the somatosensory cortex during prism adaptation.

    PubMed

    Yoon, Hee-Chul; Lee, Kyung-Hyun; Huh, Dong-Chan; Lee, Ji-Hang; Lee, Dong-Hyun

    2014-04-01

    Although the behavioral characteristics and the neural correlates of prism adaptation processes have been studied extensively, the underlying mechanism is yet to be investigated. Recently, somatosensory suppression was heralded as a mechanism for the sensory re-alignment process accompanying the adaptation. Somatosensory suppression should facilitate the re-alignment process in the proprioceptive system. The shift in the proprioceptive system takes place mostly during a concurrent visual feedback (CVF) condition; during a terminal visual feedback (TVF) condition, the visual system experiences significant adaptation (visual shift), so somatosensory suppression should have minimal functional consequences under TVF. To test this hypothesis, a repetitive transcranial magnetic stimulation (rTMS) was applied to the primary somatosensory cortex as an artificial somatosensory suppression right after the reaching initiation in CVF and TVF conditions, and changes in adaptation were observed. Because somatosensory suppression is already in effect during CVF, rTMS would cause no significant changes. During TVF with rTMS, however, significantly different patterns of adaptation could be expected when compared to a sham rTMS condition. Young adults (N = 12) participated in 4 sessions (CVF/ TVF, real/sham rTMS); visual proprioceptive, and total shifts were measured. Movement time and curvature of the reaching movement were measured during the adaptation phase. Results showed that while the total shift was unchanged, the proprioceptive shift increased and the visual shift decreased in the TVF condition when rTMS was delivered. However, the total, proprioceptive, and visual shifts were not influenced by rTMS in the CVF condition. Suppression of proprioception induced by the rTMS could be one of the requisites for successful proprioceptive shift during prism adaptation.

  9. Dual control active superconductive devices

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1993-07-20

    A superconducting active device has dual control inputs and is constructed such that the output of the device is effectively a linear mix of the two input signals. The device is formed of a film of superconducting material on a substrate and has two main conduction channels, each of which includes a weak link region. A first control line extends adjacent to the weak link region in the first channel and a second control line extends adjacent to the weak link region in the second channel. The current flowing from the first channel flows through an internal control line which is also adjacent to the weak link region of the second channel. The weak link regions comprise small links of superconductor, separated by voids, through which the current flows in each channel. Current passed through the control lines causes magnetic flux vortices which propagate across the weak link regions and control the resistance of these regions. The output of the device taken across the input to the main channels and the output of the second main channel and the internal control line will constitute essentially a linear mix of the two input signals imposed on the two control lines. The device is especially suited to microwave applications since it has very low input capacitance, and is well suited to being formed of high temperature superconducting materials since all of the structures may be formed coplanar with one another on a substrate.

  10. TASSRAP Input Module

    DTIC Science & Technology

    1977-07-29

    retrieve data necessary for the other modules to function. Initially there are 13 inputs, with the CRT dis - playing the information to be entered...id 46aý .0sso somma % 4bt--f. ft Aa W #4t - lQ *a - 4 c ,0 45 40 aK 43 ’ C = 04 ZSC 0 de *020.4 %- li’l ~ ~ ~ ~ ~ ~ & 1&.1 gol~ -,.-’ ow. -6 -N*4••1L...tv Z (𔃽 - C- ft %- ftb 0*4 *- -1 *4* (30 w ag &h 𔃾 0 a _6a .N I 0 A. 6.2 IL ILN ’ S MS 6C 0 to ~ 0 " di a S 0 m J *- -j f’ md op9 -9 $-. -6 = -A U .Af

  11. Vibration control in piping system by dual dynamic absorbers

    SciTech Connect

    Sodeyama, H.; Ikahata, N.; Sunakoda, K.; Seto, K.

    1995-12-31

    This paper deals with the applicability of a seismic response reduction method with a dual dynamic absorber for equipment, piping system, etc. in a nuclear power plant. The dual dynamic absorber which utilizes a magnetic damping effect was developed and the investigation was done to the characteristics of vibration controllability through excitation tests. As the primary stage of this study, a simple vertical straight pipe with a diameter of 60.8 mm and a length of 2,000 mm was excited by random vibration input, and amplitude of vibration level was reduced by the dual dynamic absorber mounted on the pipe. The mass ratio of the dual dynamic absorber to the straight pipe was 0.05. The result of this test was that the response reduction effect of the dual dynamic absorber for random excitations was verified. Also, the damping characteristic with fine linearity for the input level was obtained.

  12. 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

  13. 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.

  14. Intraoperative intrinsic optical imaging of human somatosensory cortex during neurosurgical operations.

    PubMed

    Sato, Katsushige; Nariai, Tadashi; Momose-Sato, Yoko; Kamino, Kohtaro

    2017-07-01

    Intrinsic optical imaging as developed by Grinvald et al. is a powerful technique for monitoring neural function in the in vivo central nervous system. The advent of this dye-free imaging has also enabled us to monitor human brain function during neurosurgical operations. We briefly describe our own experience in functional mapping of the human somatosensory cortex, carried out using intraoperative optical imaging. The maps obtained demonstrate new additional evidence of a hierarchy for sensory response patterns in the human primary somatosensory cortex.

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

    NASA Technical Reports Server (NTRS)

    Peterka, R. J.; Benolken, M. S.

    1995-01-01

    The purpose of this study 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 were 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 subjects and subjects experiencing vestibular loss were nearly identical, implying (1) that 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) that subjects with vestibular loss 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 3 times greater than the amplitude of the visual stimulus in normal subjects and subjects with vestibular loss. 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 4 in tests where somatosensory cues provided

  16. Input Multiplicities in Process Control.

    ERIC Educational Resources Information Center

    Koppel, Lowell B.

    1983-01-01

    Describes research investigating potential effect of input multiplicity on multivariable chemical process control systems. Several simple processes are shown to exhibit the possibility of theoretical developments on input multiplicity and closely related phenomena are discussed. (JN)

  17. Modeling and generating input processes

    SciTech Connect

    Johnson, M.E.

    1987-01-01

    This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.

  18. The biology of skin wetness perception and its implications in manual function and for reproducing complex somatosensory signals in neuroprosthetics.

    PubMed

    Filingeri, Davide; Ackerley, Rochelle

    2017-01-25

    Our perception of skin wetness is generated readily, yet humans have no known receptor (hygroreceptor) to signal this directly. It is easy to imagine the sensation of water running over our hands, or the feel of rain on our skin. The synthetic sensation of wetness is thought to be produced from a combination of specific skin thermal and tactile inputs, registered through thermoreceptors and mechanoreceptors, respectively. The present review explores how thermal and tactile afference from the periphery can generate the percept of wetness centrally. We propose that the main signals include information about skin cooling, signaled primarily by thinly-myelinated thermoreceptors, and rapid changes in touch, through fast-conducting, myelinated mechanoreceptors. Potential central sites for integration of these signals, and thus the perception of skin wetness, include the primary and secondary somatosensory cortices and the insula cortex. The interactions underlying these processes can also be modeled to aid in understanding and engineering the mechanisms. Further, we discuss the role that sensing wetness could play in precision grip and the dexterous manipulation of objects. We expand on these lines of inquiry to the application of the knowledge in designing and creating skin sensory feedback in prosthetics. The addition of real-time, complex sensory signals would mark a significant advance in the use and incorporation of prosthetic body parts for amputees in everyday life.

  19. Age-related changes in primary somatosensory cortex of rats: evidence for parallel degenerative and plastic-adaptive processes.

    PubMed

    Godde, Ben; Berkefeld, Thomas; David-Jürgens, Marianne; Dinse, Hubert R

    2002-11-01

    Aged rats show a characteristic decline of the sensorimotor state, most strikingly expressed in an impairment of the hindlimbs leading to significantly reduced sensory stimulation on the hindpaw. We review recent studies using optical imaging and electrophysiological recordings to investigate the effects of aging on somatosensory cortex and to identify age-related changes in terms of degeneration or plastic adaptation. For the cortical hindpaw representation, reduction of map size, receptive field enlargement and reduced response strength were described. None of these changes were reported in the forepaw representation in the same individual, however, in both the fore-and hindpaw representations response latencies and cerebral blood flow were affected. Changes of latencies and blood flow are best explained by degeneration, but the regional and specific changes of maps, receptive fields and response strength by plastic phenomena arising from the reduced sensory inputs. While the degenerative changes are not modifiable by enriched environmental conditions or application of Ca(2+) blocker, the plastic changes were fully reversible under these conditions. We discuss the implications of these findings for cognitive functions at old age and possible treatments of age-related changes in human subjects.

  20. Identifying local and descending inputs for primary sensory neurons

    PubMed Central

    Zhang, Yi; Zhao, Shengli; Rodriguez, Erica; Takatoh, Jun; Han, Bao-Xia; Zhou, Xiang; Wang, Fan

    2015-01-01

    Primary pain and touch sensory neurons not only detect internal and external sensory stimuli, but also receive inputs from other neurons. However, the neuronal derived inputs for primary neurons have not been systematically identified. Using a monosynaptic rabies viruses–based transneuronal tracing method combined with sensory-specific Cre-drivers, we found that sensory neurons receive intraganglion, intraspinal, and supraspinal inputs, the latter of which are mainly derived from the rostroventral medulla (RVM). The viral-traced central neurons were largely inhibitory but also consisted of some glutamatergic neurons in the spinal cord and serotonergic neurons in the RVM. The majority of RVM-derived descending inputs were dual GABAergic and enkephalinergic (opioidergic). These inputs projected through the dorsolateral funiculus and primarily innervated layers I, II, and V of the dorsal horn, where pain-sensory afferents terminate. Silencing or activation of the dual GABA/enkephalinergic RVM neurons in adult animals substantially increased or decreased behavioral sensitivity, respectively, to heat and mechanical stimuli. These results are consistent with the fact that both GABA and enkephalin can exert presynaptic inhibition of the sensory afferents. Taken together, this work provides a systematic view of and a set of tools for examining peri- and extrasynaptic regulations of pain-afferent transmission. PMID:26426077

  1. Enhancement of median nerve regeneration by mesenchymal stem cells engraftment in an absorbable conduit: improvement of peripheral nerve morphology with enlargement of somatosensory cortical representation

    PubMed Central

    Oliveira, Julia T.; Bittencourt-Navarrete, Ruben Ernesto; de Almeida, Fernanda M.; Tonda-Turo, Chiara; Martinez, Ana Maria B.; Franca, João G.

    2014-01-01

    We studied the morphology and the cortical representation of the median nerve (MN), 10 weeks after a transection immediately followed by treatment with tubulization using a polycaprolactone (PCL) conduit with or without bone marrow-derived mesenchymal stem cell (MSC) transplant. In order to characterize the cutaneous representation of MN inputs in primary somatosensory cortex (S1), electrophysiological cortical mapping of the somatosensory representation of the forepaw and adjacent body parts was performed after acute lesion of all brachial plexus nerves, except for the MN. This was performed in ten adult male Wistar rats randomly assigned in three groups: MN Intact (n = 4), PCL-Only (n = 3), and PCL+MSC (n = 3). Ten weeks before mapping procedures in animals from PCL-Only and PCL+MSC groups, animal were subjected to MN transection with removal of a 4-mm-long segment, immediately followed by suturing a PCL conduit to the nerve stumps with (PCL+MSC group) or without (PCL-Only group) injection of MSC into the conduit. After mapping the representation of the MN in S1, animals had a segment of the regenerated nerve processed for light and transmission electron microscopy. For histomorphometric analysis of the nerve segment, sample size was increased to five animals per experimental group. The PCL+MSC group presented a higher number of myelinated fibers and a larger cortical representation of MN inputs in S1 (3,383 ± 390 fibers; 2.3 mm2, respectively) than the PCL-Only group (2,226 ± 575 fibers; 1.6 mm2). In conclusion, MSC-based therapy associated with PCL conduits can improve MN regeneration. This treatment seems to rescue the nerve representation in S1, thus minimizing the stabilization of new representations of adjacent body parts in regions previously responsive to the MN. PMID:25360086

  2. Enhancement of median nerve regeneration by mesenchymal stem cells engraftment in an absorbable conduit: improvement of peripheral nerve morphology with enlargement of somatosensory cortical representation.

    PubMed

    Oliveira, Julia T; Bittencourt-Navarrete, Ruben Ernesto; de Almeida, Fernanda M; Tonda-Turo, Chiara; Martinez, Ana Maria B; Franca, João G

    2014-01-01

    We studied the morphology and the cortical representation of the median nerve (MN), 10 weeks after a transection immediately followed by treatment with tubulization using a polycaprolactone (PCL) conduit with or without bone marrow-derived mesenchymal stem cell (MSC) transplant. In order to characterize the cutaneous representation of MN inputs in primary somatosensory cortex (S1), electrophysiological cortical mapping of the somatosensory representation of the forepaw and adjacent body parts was performed after acute lesion of all brachial plexus nerves, except for the MN. This was performed in ten adult male Wistar rats randomly assigned in three groups: MN Intact (n = 4), PCL-Only (n = 3), and PCL+MSC (n = 3). Ten weeks before mapping procedures in animals from PCL-Only and PCL+MSC groups, animal were subjected to MN transection with removal of a 4-mm-long segment, immediately followed by suturing a PCL conduit to the nerve stumps with (PCL+MSC group) or without (PCL-Only group) injection of MSC into the conduit. After mapping the representation of the MN in S1, animals had a segment of the regenerated nerve processed for light and transmission electron microscopy. For histomorphometric analysis of the nerve segment, sample size was increased to five animals per experimental group. The PCL+MSC group presented a higher number of myelinated fibers and a larger cortical representation of MN inputs in S1 (3,383 ± 390 fibers; 2.3 mm(2), respectively) than the PCL-Only group (2,226 ± 575 fibers; 1.6 mm(2)). In conclusion, MSC-based therapy associated with PCL conduits can improve MN regeneration. This treatment seems to rescue the nerve representation in S1, thus minimizing the stabilization of new representations of adjacent body parts in regions previously responsive to the MN.

  3. mGluR5 Exerts Cell-Autonomous Influences on the Functional and Anatomical Development of Layer IV Cortical Neurons in the Mouse Primary Somatosensory Cortex

    PubMed Central

    Ballester-Rosado, Carlos J.; Sun, Hao; Huang, Jui-Yen

    2016-01-01

    Glutamate neurotransmission refines synaptic connections to establish the precise neural circuits underlying sensory processing. Deleting metabotropic glutamate receptor 5 (mGluR5) in mice perturbs cortical somatosensory map formation in the primary somatosensory (S1) cortex at both functional and anatomical levels. To examine the cell-autonomous influences of mGluR5 signaling in the morphological and functional development of layer IV spiny stellate glutamatergic neurons receiving sensory input, mGluR5 genetic mosaic mice were generated through in utero electroporation. In the S1 cortex of these mosaic brains, we found that most wild-type neurons were located in barrel rings encircling thalamocortical axon (TCA) clusters while mGluR5 knock-out (KO) neurons were placed in the septal area, the cell-sparse region separating barrels. These KO neurons often displayed a symmetrical dendritic morphology with increased dendritic complexity, in contrast to the polarized pattern of wild-type neurons. The dendritic spine density of mGluR5 KO spiny stellate neurons was significantly higher than in wild-type neurons. Whole-cell electrophysiological recordings detected a significant increase in the frequencies of spontaneous and miniature excitatory postsynaptic events in mGluR5 KO neurons compared with neighboring wild-type neurons. Our mosaic analysis provides strong evidence supporting the cell-autonomous influence of mGluR5 signaling on the functional and anatomical development of cortical glutamatergic neurons. Specifically, mGluR5 is required in cortical glutamatergic neurons for the following processes: (1) the placement of cortical glutamatergic neurons close to TCA clusters; (2) the regulation of dendritic complexity and outgrowth toward TCA clusters; (3) spinogenesis; and (4) tuning of excitatory inputs. SIGNIFICANCE STATEMENT Glutamatergic transmission plays a critical role in cortical circuit formation. Its dysfunction has been proposed as a core factor in the

  4. Governance of dual-use research: an ethical dilemma

    PubMed Central

    2009-01-01

    Abstract Scenarios where the results of well-intentioned scientific research can be used for both good and harmful purposes give rise to what is now widely known as the “dual-use dilemma”. There has been growing debate about the dual-use nature of life science research with implications for making biological weapons. This paper reviews several controversial publications that have been the focus of debates about dual-use life science research and critically examines relevant policy developments, particularly in the United States of America. Though the dual-use dilemma is inherently ethical in nature, the majority of debates about dual-use research have primarily involved science and security experts rather than ethicists. It is important that there is more ethical input into debates about the governance of dual-use research. PMID:19784453

  5. The Kepler Input Catalog

    NASA Astrophysics Data System (ADS)

    Latham, D. W.; Brown, T. M.; Monet, D. G.; Everett, M.; Esquerdo, G. A.; Hergenrother, C. W.

    2005-12-01

    The Kepler mission will monitor 170,000 planet-search targets during the first year, and 100,000 after that. The Kepler Input Catalog (KIC) will be used to select optimum targets for the search for habitable earth-like transiting planets. The KIC will include all known catalogued stars in an area of about 177 square degrees centered at RA 19:22:40 and Dec +44:30 (l=76.3 and b=+13.5). 2MASS photometry will be supplemented with new ground-based photometry obtained in the SDSS g, r, i, and z bands plus a custom filter centered on the Mg b lines, using KeplerCam on the 48-inch telescope at the Whipple Observatory on Mount Hopkins, Arizona. The photometry will be used to estimate stellar characteristics for all stars brighter than K 14.5 mag. The KIC will include effective temperature, surface gravity, metallicity, reddening, distance, and radius estimates for these stars. The CCD images are pipeline processed to produce instrumental magnitudes at PSI. The photometry is then archived and transformed to the SDSS system at HAO, where the astrophysical analysis of the stellar characteristics is carried out. The results are then merged with catalogued data at the USNOFS to produce the KIC. High dispersion spectroscopy with Hectochelle on the MMT will be used to supplement the information for many of the most interesting targets. The KIC will be released before launch for use by the astronomical community and will be available for queries over the internet. Support from the Kepler mission is gratefully acknowledged.

  6. 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

  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. Imbalance in Multiple Sclerosis: A Result of Slowed Spinal Somatosensory Conduction

    PubMed Central

    Cameron, Michelle H.; Horak, Fay B.; Herndon, Robert R.; Bourdette, Dennis

    2009-01-01

    Balance problems and falls are common in people with multiple sclerosis (MS) but their cause and nature are not well understood. It is known that MS affects many areas of the central nervous system that can impact postural responses to maintain balance, including the cerebellum and the spinal cord. Cerebellar balance disorders are associated with normal latencies but reduced scaling of postural responses. We therefore examined the latency and scaling of automatic postural responses, and their relationship to somatosensory evoked potentials (SSEPs), in 10 people with MS and imbalance and 10 age-, sex-matched, healthy controls. The latency and scaling of postural responses to backward surface translations of 5 different velocities and amplitudes, and the latency of spinal and supraspinal somatosensory conduction, were examined. Subjects with MS had large, but very delayed automatic postural response latencies compared to controls (161ms ± 31 vs 102 ± 21, p < 0.01) and these postural response latencies correlated with the latencies of their spinal SSEPs (r=0.73, p< 0.01). Subjects with MS also had normal or excessive scaling of postural response amplitude to perturbation velocity and amplitude. Longer latency postural responses were associated with less velocity scaling and more amplitude scaling. Balance deficits in people with MS appear to be caused by slowed spinal somatosensory conduction and not by cerebellar involvement. People with MS appear to compensate for their slowed spinal somatosensory conduction by increasing the amplitude scaling and the magnitude of their postural responses. PMID:18570015

  9. Human Short-Latency Somatosensory Evoked Potentials in Impact Acceleration Research: Equipment, Procedures and Techniques

    DTIC Science & Technology

    1990-10-01

    Instrumentation Data Sheet .......................... 10 Figure 8. Human Physiology Screen One ....................................... 1I1 Figure 9. Human ... Physiology Screen Two...................................... 12 Figure 10. Human Physiology Screen Three ..................................... 12 Figure...Short-Latency Somatosensory Evoked Potentials in Impact Acceleration Research ***** HUMAN PHYSIOLOGY SCREEN***** Please Read First To move from one

  10. 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.

  11. 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)

  12. Contralateral somatosensory neglect in unrestrained rats after lesion of the parietal cortex of the left hemisphere.

    PubMed

    Holm, S; Mogensen, J

    1993-01-01

    Three groups of rats were studied: a sham operated control group and two groups in which the parietal "association" cortex had been ablated in the left and right hemispheres respectively. Twenty-four hours and 8 days postoperatively the animals were subjected to a test in which their responsiveness to lateralized somatosensory stimuli was measured while the rats were left unrestrained. Additionally, an activity cage locomotion test followed immediately upon both tests of somatosensory responsiveness. Twenty-four hours postoperatively the animals in which the parietal cortex of the left hemisphere had been ablated demonstrated a significant contralateral neglect of somatosensory stimuli while the group in which the right parietal cortex had been ablated only exhibited a non-significant tendency to a contralateral neglect. While the activity cage test did not reveal an overall difference in the activity level of the three groups the latency to initiate locomotion in the activity cage was found to be significantly decreased in both ablated groups. Eight days postoperatively both ablated groups appeared fully recovered. It is concluded that ablations of the parietal "association" cortex of the rat are associated with a syndrome of contralateral somatosensory neglect that can even be demonstrated if the animals are left unrestrained during testing.

  13. Ankyrin-B structurally defines terminal microdomains of peripheral somatosensory axons.

    PubMed

    Engelhardt, Maren; Vorwald, Silke; Sobotzik, Jürgen-Markus; Bennett, Vann; Schultz, Christian

    2013-07-01

    Axons are subdivided into functionally organized microdomains, which are required for generation and propagation of action potentials (APs). In the central nervous system (CNS), APs are generated near the soma in the axon initial segment (AIS) and propagated by nodes of Ranvier (noR). The crucial role of the membrane adapter proteins ankyrin-B and ankyrin-G as organizers of AIS and noR is now well established. By comparison, little is known on the localization and function of these proteins in sensory axon terminals of the peripheral nervous systems (PNS). Here, we tested the hypothesis that somatosensory PNS terminals are organized by distinct members of the ankyrin protein family. We discovered a specific distribution of ankyrin-B in somatosensory axon terminals of skin and muscle. Specifically, ankyrin-B was localized along the membrane of axons innervating Meissner corpuscles, Pacinian corpuscles and hair follicle receptors. Likewise, proprioceptive terminals of muscle spindles exhibited prominent ankyrin-B expression. Furthermore, ankyrin-B expression extended into nociceptive and thermoceptive intraepidermal nerve fibers. Interestingly, all studied somatosensory terminals were largely devoid of ankyrin-G, indicating that this scaffolding protein does not contribute to organization of mechanoelectric transduction zones in peripheral somatosensory neurons. Instead, we propose that ankyrin-B serves as a major membrane organizer in mechanoreceptive and nociceptive terminals of the PNS.

  14. 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…

  15. Early changes in somatosensory function in spinal pain: protocol for a systematic review

    PubMed Central

    2013-01-01

    Background Back and neck pain are common conditions that have a high burden of disease. Changes in somatosensory function in the periphery, the spinal cord and the brain have been well documented at the time when these conditions have become chronic. It is unknown, however, how early these changes occur, what the timecourse is of sensory dysfunction and what the specific nature of these changes are in the first 12 weeks after onset of pain. In this paper, we describe the protocol for a systematic review of the literature on somatosensory dysfunction in the first 12 weeks after pain onset. Methods and design We will conduct a comprehensive search for articles indexed in the databases Ovid MEDLINE, Ovid Embase, Ovid PsycINFO and Cochrane Central Register of Controlled Trial (CENTRAL) from their inception to August 2013 that report on any aspect of somatosensory function in acute or subacute neck or back pain. Two independent reviewers will screen studies for eligibility, assess risk of bias and extract relevant data. Results will be tabulated and a narrative synthesis of the results conducted. Discussion Currently, there is a gap in our knowledge about the timing of somatosensory changes in back and neck pain. The systematic review outlined in this protocol aims to address this knowledge gap and inform developments in diagnostic tools and pain mechanism-based treatments. Trial Registration Our protocol has been registered on PROSPERO, CRD42013005113. PMID:24088219

  16. Somatosensory Contribution to Motor Learning Due to Facial Skin Deformation

    PubMed Central

    Ito, Takayuki

    2010-01-01

    Motor learning is dependent on kinesthetic information that is obtained both from cutaneous afferents and from muscle receptors. In human arm movement, information from these two kinds of afferents is largely correlated. The facial skin offers a unique situation in which there are plentiful cutaneous afferents and essentially no muscle receptors and, accordingly, experimental manipulations involving the facial skin may be used to assess the possible role of cutaneous afferents in motor learning. We focus here on the information for motor learning provided by the deformation of the facial skin and the motion of the lips in the context of speech. We used a robotic device to slightly stretch the facial skin lateral to the side of the mouth in the period immediately preceding movement. We found that facial skin stretch increased lip protrusion in a progressive manner over the course of a series of training trials. The learning was manifest in a changed pattern of lip movement, when measured after learning in the absence of load. The newly acquired motor plan generalized partially to another speech task that involved a lip movement of different amplitude. Control tests indicated that the primary source of the observed adaptation was sensory input from cutaneous afferents. The progressive increase in lip protrusion over the course of training fits with the basic idea that change in sensory input is attributed to motor performance error. Sensory input, which in the present study precedes the target movement, is credited to the target-related motion, even though the skin stretch is released prior to movement initiation. This supports the idea that the nervous system generates motor commands on the assumption that sensory input and kinematic error are in register. PMID:20592121

  17. Distinct α- and β-band rhythms over rat somatosensory cortex with similar properties as in humans.

    PubMed

    Fransen, Anne M M; Dimitriadis, George; van Ede, Freek; Maris, Eric

    2016-06-01

    We demonstrate distinct α- (7-14 Hz) and β-band (15-30 Hz) rhythms in rat somatosensory cortex in vivo using epidural electrocorticography recordings. Moreover, we show in rats that a genuine β-rhythm coexists alongside β-activity that reflects the second harmonic of the arch-shaped somatosensory α-rhythm. This demonstration of a genuine somatosensory β-rhythm depends on a novel quantification of neuronal oscillations that is based on their rhythmic nature: lagged coherence. Using lagged coherence, we provide two lines of evidence that this somatosensory β-rhythm is distinct from the second harmonic of the arch-shaped α-rhythm. The first is based on the rhythms' spatial properties: the α- and β-rhythms are demonstrated to have significantly different topographies. The second is based on the rhythms' temporal properties: the lagged phase-phase coupling between the α- and β-rhythms is demonstrated to be significantly less than would be expected if both reflected a single underlying nonsinusoidal rhythm. Finally, we demonstrate that 1) the lagged coherence spectrum is consistent between signals from rat and human somatosensory cortex; and 2) a tactile stimulus has the same effect on the somatosensory α- and β-rhythms in both rats and humans, namely suppressing them. Thus we not only provide evidence for the existence of genuine α- and β-rhythms in rat somatosensory cortex, but also for their homology to the primate sensorimotor α- and β-rhythms.

  18. Expectation violation and attention to pain jointly modulate neural gain in somatosensory cortex.

    PubMed

    Fardo, Francesca; Auksztulewicz, Ryszard; Allen, Micah; Dietz, Martin J; Roepstorff, Andreas; Friston, Karl J

    2017-03-21

    The neural processing and experience of pain are influenced by both expectations and attention. For example, the amplitude of event-related pain responses is enhanced by both novel and unexpected pain, and by moving the focus of attention towards a painful stimulus. Under predictive coding, this congruence can be explained by appeal to a precision-weighting mechanism, which mediates bottom-up and top-down attentional processes by modulating the influence of feedforward and feedback signals throughout the cortical hierarchy. The influence of expectation and attention on pain processing can be mapped onto changes in effective connectivity between or within specific neuronal populations, using a canonical microcircuit (CMC) model of hierarchical processing. We thus implemented a CMC within dynamic causal modelling for magnetoencephalography in human subjects, to investigate how expectation violation and attention to pain modulate intrinsic (within-source) and extrinsic (between-source) connectivity in the somatosensory hierarchy. This enabled us to establish whether both expectancy and attentional processes are mediated by a similar precision-encoding mechanism within a network of somatosensory, frontal and parietal sources. We found that both unexpected and attended pain modulated the gain of superficial pyramidal cells in primary and secondary somatosensory cortex. This modulation occurred in the context of increased lateralized recurrent connectivity between somatosensory and fronto-parietal sources, driven by unexpected painful occurrences. Finally, the strength of effective connectivity parameters in S1, S2 and IFG predicted individual differences in subjective pain modulation ratings. Our findings suggest that neuromodulatory gain control in the somatosensory hierarchy underlies the influence of both expectation violation and attention on cortical processing and pain perception.

  19. 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

  20. Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials

    PubMed Central

    Jones, Matthew D.; Taylor, Janet L.; Booth, John; Barry, Benjamin K.

    2016-01-01

    Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1–SEPs; Experiment 2–LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = −0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = −0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = −0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = −0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia. PMID:27965587

  1. Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

    PubMed

    Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

    2016-01-01

    Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

  2. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  3. SDR Input Power Estimation Algorithms

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  4. Intermediate inputs and economic productivity.

    PubMed

    Baptist, Simon; Hepburn, Cameron

    2013-03-13

    Many models of economic growth exclude materials, energy and other intermediate inputs from the production function. Growing environmental pressures and resource prices suggest that this may be increasingly inappropriate. This paper explores the relationship between intermediate input intensity, productivity and national accounts using a panel dataset of manufacturing subsectors in the USA over 47 years. The first contribution is to identify sectoral production functions that incorporate intermediate inputs, while allowing for heterogeneity in both technology and productivity. The second contribution is that the paper finds a negative correlation between intermediate input intensity and total factor productivity (TFP)--sectors that are less intensive in their use of intermediate inputs have higher productivity. This finding is replicated at the firm level. We propose tentative hypotheses to explain this association, but testing and further disaggregation of intermediate inputs is left for further work. Further work could also explore more directly the relationship between material inputs and economic growth--given the high proportion of materials in intermediate inputs, the results in this paper are suggestive of further work on material efficiency. Depending upon the nature of the mechanism linking a reduction in intermediate input intensity to an increase in TFP, the implications could be significant. A third contribution is to suggest that an empirical bias in productivity, as measured in national accounts, may arise due to the exclusion of intermediate inputs. Current conventions of measuring productivity in national accounts may overstate the productivity of resource-intensive sectors relative to other sectors.

  5. Sensory inputs control the integration of neurogliaform interneurons into cortical circuits.

    PubMed

    De Marco García, Natalia V; Priya, Rashi; Tuncdemir, Sebnem N; Fishell, Gord; Karayannis, Theofanis

    2015-03-01

    Neuronal microcircuits in the superficial layers of the mammalian cortex provide the substrate for associative cortical computation. Inhibitory interneurons constitute an essential component of the circuitry and are fundamental to the integration of local and long-range information. Here we report that, during early development, superficially positioned Reelin-expressing neurogliaform interneurons in the mouse somatosensory cortex receive afferent innervation from both cortical and thalamic excitatory sources. Attenuation of ascending sensory, but not intracortical, excitation leads to axo-dendritic morphological defects in these interneurons. Moreover, abrogation of the NMDA receptors through which the thalamic inputs signal results in a similar phenotype, as well as in the selective loss of thalamic and a concomitant increase in intracortical connectivity. These results suggest that thalamic inputs are critical in determining the balance between local and long-range connectivity and are fundamental to the proper integration of Reelin-expressing interneurons into nascent cortical circuits.

  6. Sensory inputs control the integration of neurogliaform interneurons into cortical circuits

    PubMed Central

    De Marco García, Natalia V; Priya, Rashi; Tuncdemir, Sebnem N; Fishell, Gord; Karayannis, Theofanis

    2015-01-01

    Neuronal microcircuits in the superficial layers of the mammalian cortex provide the substrate for associative cortical computation. Inhibitory interneurons constitute an essential component of the circuitry and are fundamental to the integration of local and long-range information. Here we report that, during early development, superficially positioned Reelin-expressing neurogliaform interneurons in the mouse somatosensory cortex receive afferent innervation from both cortical and thalamic excitatory sources. Attenuation of ascending sensory, but not intracortical, excitation leads to axo-dendritic morphological defects in these interneurons. Moreover, abrogation of the NMDA receptors through which the thalamic inputs signal results in a similar phenotype, as well as in the selective loss of thalamic and a concomitant increase in intracortical connectivity. These results suggest that thalamic inputs are critical in determining the balance between local and long-range connectivity and are fundamental to the proper integration of Reelin-expressing interneurons into nascent cortical circuits. PMID:25664912

  7. Self-organisation in the human visual system--visuo-motor processing with congenitally abnormal V1 input.

    PubMed

    Wolynski, Barbara; Kanowski, Martin; Meltendorf, Synke; Behrens-Baumann, Wolfgang; Hoffmann, Michael B

    2010-11-01

    Due to an abnormal projection of the temporal retina the albinotic primary visual cortex receives substantial input from the ipsilateral visual field. To test whether representation abnormalities are also evident in higher tier visual, and in motor and somatosensory cortices, brain activity was measured with fMRI in 14 subjects with albinism performing a visuo-motor task. During central fixation, a blue or red target embedded in a distractor array was presented for 250 ms in the left or right visual hemifield. After a delay, the subjects were prompted to indicate with left or right thumb button presses the target presence in the upper or lower hemifield. The fMRI responses were evaluated for different regions of interest concerned with visual, motor and somatosensory processing and compared to previously acquired data from 14 controls. The following results were obtained: (1) in albinism the hit rates in the visuo-motor task were indistinguishable from normal. (2) In area MT and the intraparietal sulcus there was an indication of abnormal lateralisation patterns. (3) Largely normal lateralisation patterns were evident in motor and somatosensory cortices. It is concluded that in human albinism, the abnormal visual field representation is made available for visuo-motor processing with a motor cortex that comprises an essentially normal lateralisation. Consequently, specific adaptations of the mechanisms mediating visuo-motor integration are required in albinism.

  8. Dual Wavelength Lasers

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.

    2010-01-01

    Dual wavelength lasers are discussed, covering fundamental aspects on the spectroscopy and laser dynamics of these systems. Results on Tm:Ho:Er:YAG dual wavelength laser action (Ho at 2.1 m and Er at 2.9 m) as well as Nd:YAG (1.06 and 1.3 m) are presented as examples of such dual wavelength systems. Dual wavelength lasers are not common, but there are criteria that govern their behavior. Based on experimental studies demonstrating simultaneous dual wavelength lasing, some general conclusions regarding the successful operation of multi-wavelength lasers can be made.

  9. Encoding of whisker input by cerebellar Purkinje cells

    PubMed Central

    Bosman, Laurens W J; Koekkoek, Sebastiaan K E; Shapiro, Joël; Rijken, Bianca F M; Zandstra, Froukje; van der Ende, Barry; Owens, Cullen B; Potters, Jan-Willem; de Gruijl, Jornt R; Ruigrok, Tom J H; De Zeeuw, Chris I

    2010-01-01

    The cerebellar cortex is crucial for sensorimotor integration. Sensorimotor inputs converge on cerebellar Purkinje cells via two afferent pathways: the climbing fibre pathway triggering complex spikes, and the mossy fibre–parallel fibre pathway, modulating the simple spike activities of Purkinje cells. We used, for the first time, the mouse whisker system as a model system to study the encoding of somatosensory input by Purkinje cells. We show that most Purkinje cells in ipsilateral crus 1 and crus 2 of awake mice respond to whisker stimulation with complex spike and/or simple spike responses. Single-whisker stimulation in anaesthetised mice revealed that the receptive fields of complex spike and simple spike responses were strikingly different. Complex spike responses, which proved to be sensitive to the amplitude, speed and direction of whisker movement, were evoked by only one or a few whiskers. Simple spike responses, which were not affected by the direction of movement, could be evoked by many individual whiskers. The receptive fields of Purkinje cells were largely intermingled, and we suggest that this facilitates the rapid integration of sensory inputs from different sources. Furthermore, we describe that individual Purkinje cells, at least under anaesthesia, may be bound in two functional ensembles based on the receptive fields and the synchrony of the complex spike and simple spike responses. The ‘complex spike ensembles’ were oriented in the sagittal plane, following the anatomical organization of the climbing fibres, while the ‘simple spike ensembles’ were oriented in the transversal plane, as are the beams of parallel fibres. PMID:20724365

  10. Intracortical and Thalamocortical Connections of the Hand and Face Representations in Somatosensory Area 3b of Macaque Monkeys and Effects of Chronic Spinal Cord Injuries.

    PubMed

    Chand, Prem; Jain, Neeraj

    2015-09-30

    Brains of adult monkeys with chronic lesions of dorsal columns of spinal cord at cervical levels undergo large-scale reorganization. Reorganization results in expansion of intact chin inputs, which reactivate neurons in the deafferented hand representation in the primary somatosensory cortex (area 3b), ventroposterior nucleus of the thalamus and cuneate nucleus of the brainstem. A likely contributing mechanism for this large-scale plasticity is sprouting of axons across the hand-face border. Here we determined whether such sprouting takes place in area 3b. We first determined the extent of intrinsic corticocortical connectivity between the hand and the face representations in normal area 3b. Small amounts of neuroanatomical tracers were injected in these representations close to the electrophysiologically determined hand-face border. Locations of the labeled neurons were mapped with respect to the detailed electrophysiological somatotopic maps and histologically determined hand-face border revealed in sections of the flattened cortex stained for myelin. Results show that intracortical projections across the hand-face border are few. In monkeys with chronic unilateral lesions of the dorsal columns and expanded chin representation, connections across the hand-face border were not different compared with normal monkeys. Thalamocortical connections from the hand and face representations in the ventroposterior nucleus to area 3b also remained unaltered after injury. The results show that sprouting of intrinsic connections in area 3b or the thalamocortical inputs does not contribute to large-scale cortical plasticity. Significance statement: Long-term injuries to dorsal spinal cord in adult primates result in large-scale somatotopic reorganization due to which chin inputs expand into the deafferented hand region. Reorganization takes place in multiple cortical areas, and thalamic and medullary nuclei. To what extent this brain reorganization due to dorsal column injuries

  11. Neuroplastic changes related to pain occur at multiple levels of the human somatosensory system: A somatosensory-evoked potentials study in patients with cervical radicular pain.

    PubMed

    Tinazzi, M; Fiaschi, A; Rosso, T; Faccioli, F; Grosslercher, J; Aglioti, S M

    2000-12-15

    Studies suggest that pain may play a major role in determining cortical rearrangements in the adult human somatosensory system. Most studies, however, have been performed under conditions whereby pain coexists with massive deafferentation (e.g., amputations). Moreover, no information is available on whether spinal and brainstem changes contribute to pain-related reorganizational processes in humans. Here we assess the relationships between pain and plasticity by recording somatosensory-evoked potentials (SEPs) in patients who complained of pain to the right thumb after a right cervical monoradiculopathy caused by compression of the sixth cervical root, but did not present with clinical or neurophysiological signs of deafferentation. Subcortical and cortical potentials evoked by stimulation of digital nerves of the right thumb and middle finger were compared with those obtained after stimulation of the left thumb and middle finger and with those obtained in a control group tested in comparable conditions. Amplitudes of spinal N13, brainstem P14, parietal N20 and P27, and frontal N30 potentials after stimulation of the painful right thumb were greater than those of the nonpainful left thumb and showed a positive correlation with magnitude of pain. This right-left asymmetry was absent after stimulation of the patients' middle fingers and in control subjects. Results suggest that chronic cervical radicular pain is associated with changes in neural activity at multiple levels of the somatosensory system. The absence of correlation between the amplitude of spinal, brainstem, and cortical components of SEPs suggests that enhancement of cortical activity is not a simple amplification of subcortical enhancement.

  12. Automatic differentiation using vectorized hyper dual numbers

    NASA Astrophysics Data System (ADS)

    Swaroop, Kshitiz

    Sensitivity analysis is a method to measure the change in a dependent variable with respect to one or more independent variables with uses including optimization, design analysis and risk modeling. Conventional methods like finite difference suffer from both truncation, subtraction errors and cannot be used to simultaneously calculate derivatives of an output with respect to multiple inputs (commonly seen in optimization problems). Automatic Differentiation tackles all these issues successfully allowing us to calculate derivatives of any variable with respect to the independent variables in a computer program up to machine precision without any significant user input. Vectorized Hyper Dual Numbers, an extension of Hyper Dual Numbers, which allows the user to automatically calculate both the Hessian and derivative along with the function evaluation is developed for this thesis. The method is then used for the sizing and layup of a composite wind turbine blade as a proof of concept.

  13. Effects of age on negative BOLD signal changes in the primary somatosensory cortex.

    PubMed

    Gröschel, Sonja; Sohns, Jan Martin; Schmidt-Samoa, Carsten; Baudewig, Jürgen; Becker, Lars; Dechent, Peter; Kastrup, Andreas

    2013-05-01

    In addition to a contralateral activation of the primary and secondary somatosensory cortices, peripheral sensory stimulation has been shown to elicit responses in the ipsilateral primary somatosensory cortex (SI). In particular, evidence is accumulating that processes of interhemispheric inhibition as depicted by negative blood oxygenation level dependent (BOLD) signal changes are part of somatosensory processes. The aim of the study was to analyze age-related differences in patterns of cerebral activation in the somatosensory system in general and processes of interhemispheric inhibition in particular. For this, a functional magnetic resonance imaging (fMRI) study was performed including 14 younger (mean age 23.3±0.9years) and 13 healthy older participants (mean age 73.2±8.3years). All subjects were scanned during peripheral electrical median nerve stimulation (40Hz) to obtain BOLD responses in the somatosensory system. Moreover, the individual current perception threshold (CPT) as a quantitative measure of sensory function was determined in a separate psychophysical testing. Significant increases in BOLD signal across the entire group could be measured within the contralateral SI, in the bilateral secondary somatosensory cortex (SII), the contralateral supplementary motor area and the insula. Negative BOLD signal changes were delineated in ipsilateral SI/MI as well as in the ipsilateral thalamus and basal ganglia. After comparing the two groups, only the cortical deactivation in ipsilateral SI in the early stimulation phase as well as the activation in contralateral SI and SII in the late stimulation block remained as statistically significant differences between the two groups. The psychophysical experiments yielded a significant age-dependent effect of CPT change with less difference in the older group which is in line with the significantly smaller alterations in maximal BOLD signal change in the contra- and ipsilateral SI found between the two groups

  14. REL - English Bulk Data Input.

    ERIC Educational Resources Information Center

    Bigelow, Richard Henry

    A bulk data input processor which is available for the Rapidly Extensible Language (REL) English versions is described. In REL English versions, statements that declare names of data items and their interrelationships normally are lines from a terminal or cards in a batch input stream. These statements provide a convenient means of declaring some…

  15. Inputs for L2 Acquisition.

    ERIC Educational Resources Information Center

    Saleemi, Anjum P.

    1989-01-01

    Major approaches of describing or examining linguistic data from a potential target language (input) are analyzed for adequacy in addressing the concerns of second language learning theory. Suggestions are made for making the best of these varied concepts of input and for reformulation of a unified concept. (MSE)

  16. Input in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Gass, Susan M., Ed.; Madden, Carolyn G., Ed.

    This collection of conference papers includes: "When Does Teacher Talk Work as Input?"; "Cultural Input in Second Language Learning"; "Skilled Variation in a Kindergarten Teacher's Use of Foreigner Talk"; "Teacher-Pupil Interaction in Second Language Development"; "Foreigner Talk in the University…

  17. Contributions of skin and muscle afferent input to movement sense in the human hand.

    PubMed

    Cordo, Paul J; Horn, Jean-Louis; Künster, Daniela; Cherry, Anne; Bratt, Alex; Gurfinkel, Victor

    2011-04-01

    In the stationary hand, static joint-position sense originates from multimodal somatosensory input (e.g., joint, skin, and muscle). In the moving hand, however, it is uncertain how movement sense arises from these different submodalities of proprioceptors. In contrast to static-position sense, movement sense includes multiple parameters such as motion detection, direction, joint angle, and velocity. Because movement sense is both multimodal and multiparametric, it is not known how different movement parameters are represented by different afferent submodalities. In theory, each submodality could redundantly represent all movement parameters, or, alternatively, different afferent submodalities could be tuned to distinctly different movement parameters. The study described in this paper investigated how skin input and muscle input each contributes to movement sense of the hand, in particular, to the movement parameters dynamic position and velocity. Healthy adult subjects were instructed to indicate with the left hand when they sensed the unseen fingers of the right hand being passively flexed at the metacarpophalangeal (MCP) joint through a previously learned target angle. The experimental approach was to suppress input from skin and/or muscle: skin input by anesthetizing the hand, and muscle input by unexpectedly extending the wrist to prevent MCP flexion from stretching the finger extensor muscle. Input from joint afferents was assumed not to play a significant role because the task was carried out with the MCP joints near their neutral positions. We found that, during passive finger movement near the neutral position in healthy adult humans, both skin and muscle receptors contribute to movement sense but qualitatively differently. Whereas skin input contributes to both dynamic position and velocity sense, muscle input may contribute only to velocity sense.

  18. Guidelines and recommendations for assessment of somatosensory function in oro-facial pain conditions--a taskforce report.

    PubMed

    Svensson, P; Baad-Hansen, L; Pigg, M; List, T; Eliav, E; Ettlin, D; Michelotti, A; Tsukiyama, Y; Matsuka, Y; Jääskeläinen, S K; Essick, G; Greenspan, J D; Drangsholt, M

    2011-05-01

    The goals of an international taskforce on somatosensory testing established by the Special Interest Group of Oro-facial Pain (SIG-OFP) under the International Association for the Study of Pain (IASP) were to (i) review the literature concerning assessment of somatosensory function in the oro-facial region in terms of techniques and test performance, (ii) provide guidelines for comprehensive and screening examination procedures, and (iii) give recommendations for future development of somatosensory testing specifically in the oro-facial region. Numerous qualitative and quantitative psychophysical techniques have been proposed and used in the description of oro-facial somatosensory function. The selection of technique includes time considerations because the most reliable and accurate methods require multiple repetitions of stimuli. Multiple-stimulus modalities (mechanical, thermal, electrical, chemical) have been applied to study oro-facial somatosensory function. A battery of different test stimuli is needed to obtain comprehensive information about the functional integrity of the various types of afferent nerve fibres. Based on the available literature, the German Neuropathic Pain Network test battery appears suitable for the study of somatosensory function within the oro-facial area as it is based on a wide variety of both qualitative and quantitative assessments of all cutaneous somatosensory modalities. Furthermore, these protocols have been thoroughly described and tested on multiple sites including the facial skin and intra-oral mucosa. Standardisation of both comprehensive and screening examination techniques is likely to improve the diagnostic accuracy and facilitate the understanding of neural mechanisms and somatosensory changes in different oro-facial pain conditions and may help to guide management.

  19. Orthogonal topography in the parallel input architecture of songbird HVC.

    PubMed

    Elliott, Kevin C; Wu, Wei; Bertram, Richard; Hyson, Richard L; Johnson, Frank

    2017-02-11

    Neural activity within the cortical premotor nucleus HVC (acronym is name) encodes the learned songs of adult male zebra finches (Taeniopygia guttata). HVC activity is driven and/or modulated by a group of five afferent nuclei (the Medial Magnocellular nucleus of the Anterior Nidopallium, MMAN; Nucleus Interface, NIf; nucleus Avalanche, Av; the Robust nucleus of the Arcopallium, RA; the Uvaeform nucleus, Uva). While earlier evidence suggested that HVC receives a uniformly distributed and nontopographic pattern of afferent input, recent evidence suggests this view is incorrect (Basista et al., ). Here, we used a double-labeling strategy (varying both the distance between and the axial orientation of dual tracer injections into HVC) to reveal a massively parallel and in some cases topographic pattern of afferent input. Afferent neurons target only one rostral or caudal location within medial or lateral HVC, and each HVC location receives convergent input from each afferent nucleus in parallel. Quantifying the distributions of single-labeled cells revealed an orthogonal topography in the organization of afferent input from MMAN and NIf, two cortical nuclei necessary for song learning. MMAN input is organized across the lateral-medial axis whereas NIf input is organized across the rostral-caudal axis. To the extent that HVC activity is influenced by afferent input during the learning, perception, or production of song, functional models of HVC activity may need revision to account for the parallel input architecture of HVC, along with the orthogonal input topography of MMAN and NIf. J. Comp. Neurol., 2016. © 2016 Wiley Periodicals, Inc.

  20. 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.

  1. Ethosuximide Affects Paired-Pulse Facilitation in Somatosensory Cortex of WAG\\Rij Rats as a Model of Absence Seizure

    PubMed Central

    Ghamkhari Nejad, Ghazaleh; Shahabi, Parviz; Alipoor, Mohamad Reza; Ghaderi Pakdel, Firouz; Asghari, Mohammad; Sadighi Alvandi, Mina

    2015-01-01

    Purpose: The interaction between somatosensory cortex and thalamus via a thalamocortical loop is a theory behind induction of absence epilepsy. Inside peri-oral somatosensory (S1po) and primary somatosensory forelimb (S1fl) regions, excitatory and inhibitory systems are not balanced and GABAergic inhibitory synapses seem to play a fundamental role in short-term plasticity alterations. Methods: We investigated the effects of Ethosuximide on presynaptic changes by utilizing paired-pulse stimulation that was recorded from somatosensory cortex in 18 WAG\\Rij rats during epileptic activity. A twisted tripolar electrode including two stimulating electrodes and one recording electrode was implanted into the S1po and S1FL according to stereotaxic landmarks. Paired-pulses (200 µs, 100-1000 µA, 0.1 Hz) were applied to somatosensory cortex at 50, 100, 400, 500 ms inter-pulse intervals for 50 min period. Results: The results showed that paired-pulse facilitation was significantly reduced at all intervals in all times, but compared to the control group of epileptic WAG/Rij rats (p<0.05), it was exceptional about the first 10 minutes after the injection. At the intervals of 50 and 100 ms, a remarkable PPD was found in second, third, fourth and fifth 10-min post injection. Conclusion: These experiments indicate that Ethosuximide has effects on presynaptic facilitation in somatosensory cortex inhibitory loops by alteration in GABA levels that leads to a markedly diminished PPF in paired-pulse stimulation. PMID:26819920

  2. Spinal direct current stimulation modulates the activity of gracile nucleus and primary somatosensory cortex in anaesthetized rats

    PubMed Central

    Aguilar, J; Pulecchi, F; Dilena, R; Oliviero, A; Priori, A; Foffani, G

    2011-01-01

    Abstract Afferent somatosensory activity from the spinal cord has a profound impact on the activity of the brain. Here we investigated the effects of spinal stimulation using direct current, delivered at the thoracic level, on the spontaneous activity and on the somatosensory evoked potentials of the gracile nucleus, which is the main entry point for hindpaw somatosensory signals reaching the brain from the dorsal columns, and of the primary somatosensory cortex in anaesthetized rats. Anodal spinal direct current stimulation (sDCS) increased the spontaneous activity and decreased the amplitude of evoked responses in the gracile nucleus, whereas cathodal sDCS produced the opposite effects. At the level of the primary somatosensory cortex, the changes in spontaneous activity induced by sDCS were consistent with the effects observed in the gracile nucleus, but the changes in cortical evoked responses were more variable and state dependent. Therefore, sDCS can modulate in a polarity-specific manner the supraspinal activity of the somatosensory system, offering a versatile bottom-up neuromodulation technique that could potentially be useful in a number of clinical applications. PMID:21825031

  3. Interhemispheric modulation of sensory transmission in the primary somatosensory cortex of rats.

    PubMed

    Shin, H C; Won, C K; Jung, S C; Oh, S; Park, S; Sohn, J H

    1997-07-18

    Single unit responses of the primary somatosensory (SI) cortical neurons to the stimulation of the forepaw single digit were monitored in anesthetized rats before and after subcutaneous injection of lidocaine to an ipsilateral homologous receptive field (IHRF). Quantitative determination of the temporal changes of afferent sensory transmission was done by analyzing poststimulus time histograms of unit responses. Temporary deafferentation to the IHRF induced immediate, but reversible suppression of afferent sensory transmission in the SI cortex and this suppression lasts up to 35 min post-deafferentation period (during 10-15 min, -21.81 +/- 5.9%, P < 0.01). This result suggests that temporary absence of afferent inflow from the digit to the SI cortex may exert interhemispheric modulation of afferent sensory transmission in the opposite somatosensory cortex of anesthetized rats.

  4. 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.

  5. Tactile representation in somatosensory thalamus (VPL) and cortex (S1) of awake primate and the plasticity induced by VPL neuroprosthetic stimulation.

    PubMed

    Song, Weiguo; Semework, Mulugeta

    2015-11-02

    To further understand how tactile information is carried in somatosensory cortex (S1) and the thalamus (VPL), and how neuronal plasticity after neuroprosthetic stimulation affects sensory encoding, we chronically implanted microelectrode arrays across hand areas in both S1 and VPL, where neuronal activities were simultaneously recorded during tactile stimulation on the finger pad of awake monkeys. Tactile information encoded in the firing rate of individual units (rate coding) or in the synchrony of unit pairs (synchrony coding) was quantitatively assessed within the information theoretic-framework. We found that tactile information encoded in VPL was higher than that encoded in S1 for both rate coding and synchrony coding; rate coding carried greater information than synchrony coding for the same recording area. With the aim for neuroprosthetic stimulation, plasticity of the circuit was tested after 30 min of VPL electrical stimulation, where stimuli were delivered either randomly or contingent on the spiking of an S1 unit. We showed that neural encoding in VPL was more stable than in S1, which depends not only on the thalamic input but also on recurrent feedback. The percent change of mutual-information after stimulation was increased with closed-loop stimulation, but decreased with random stimulation. The underlying mechanisms during closed-loop stimulation might be spike-timing-dependent plasticity, while frequency-dependent synaptic plasticity might play a role in random stimulation. Our results suggest that VPL could be a promising target region for somatosensory stimulation with closed-loop brain-machine-interface applications.

  6. Can an electro-tactile vestibular substitution system improve balance in patients with unilateral vestibular loss under altered somatosensory conditions from the foot and ankle?

    PubMed

    Vuillerme, N; Hlavackova, P; Franco, C; Diot, B; Demongeot, J; Payan, Y

    2011-01-01

    This pilot study aimed at assessing the feasibility and the effectiveness of an electro Electro-tactile Vestibular Substitution System (EVSS) in patients with unilateral vestibular loss under normal and altered somatosensory conditions from the foot and ankle. Four unilateral vestibular-defective patients voluntarily participated in the experiment. They were asked to stand upright as still as possible with their eyes closed in two Normal and Altered foot and ankle sensory conditions. In the Normal condition, the postural task was executed on a firm support surface constituted by the force platform. In the Altered condition, a 2-cm thick foam support surface was placed under the participants' feet. These two foot and ankle sensory conditions were executed under two No EVSS and EVSS experimental conditions. The No EVSS condition served as a control condition. In the EVSS condition, participants executed the postural task using a biofeedback system whose underlying principle consisted of supplying them with additional information about their head orientation/motion with respect to gravitational vertical through electro-tactile stimulation of their tongue. Centre of foot pressure displacements (CoP) were recorded using the force platform. Results showed that, relative to the No EVSS condition, the EVSS condition decreased CoP displacements in both the Normal and the Altered foot and ankle sensory conditions. Interestingly, the stabilizing effect was more pronounced in the Altered than in the Normal foot and ankle sensory condition. These preliminary results suggest that patients with unilateral vestibular loss were able to take advantage to a head position-based electro-tactile tongue biofeedback to mitigate the postural perturbation induced by alteration of somatosensory input from the foot and the ankle.

  7. Interaction of vestibular, somatosensory and visual signals for postural control and motion perception under terrestrial and microgravity conditions--a conceptual model.

    PubMed

    Mergner, T; Rosemeier, T

    1998-11-01

    This article considers the intersensory interaction mechanisms and biomechanical aspects of human spatially oriented behavior and asks to what extent these are interrelated on earth by gravity and how they might be affected under microgravity. The interactions between vestibular, somatosensory and visual inputs for postural control are obscured by several complications (biomechanics, multi-body dynamics, multimodal feedback control, cognition etc.). However, they can be revealed in psychophysical studies on human self-motion perception. Based on such studies, we present a conceptual model, which we think is valid also for postural control. It accounts for the multi-segmental structure of the body, allowing local control of inter-segmental joints, but uses one global reference system for all segments, which is derived from the intersensory interactions. We hold that, at a sensory level, the system is tied together by linkages between vestibular, visual and somatosensory information which develop through experience of inertial and gravitational reaction forces. On earth these linkages are established even in the absence of active behavior by gravity, allowing the incorporation of one's body and its support into a notion (Gestalt) of ourselves in the environment. Under microgravity, in contrast, the linkages have to be actively established for postural and perceptual stability in the environment (e.g., by grasping a handle on the wall). From this work we recommend that future research under altered gravity conditions should be guided by models that include biomechanics, considerations of intersensory interaction and dynamic control mechanisms. Such an integrative conceptual framework will be helpful for reaching a general understanding of spatially oriented behavior.

  8. Vestibular inputs to human motion-sensitive visual cortex.

    PubMed

    Smith, Andrew T; Wall, Matthew B; Thilo, Kai V

    2012-05-01

    Two crucial sources of information available to an organism when moving through an environment are visual and vestibular stimuli. Macaque cortical area MSTd processes visual motion, including cues to self-motion arising from optic flow and also receives information about self-motion from the vestibular system. In humans, whether human MST (hMST) receives vestibular afferents is unknown. We have combined 2 techniques, galvanic vestibular stimulation and functional MRI (fMRI), to show that hMST is strongly activated by vestibular stimulation in darkness, whereas adjacent area MT is unaffected. The activity cannot be explained in terms of somatosensory stimulation at the electrode site. Vestibular input appears to be confined to the anterior portion of hMST, suggesting that hMST as conventionally defined may contain 2 subregions. Vestibular activity was also seen in another area previously implicated in processing visual cues to self-motion, namely the cingulate sulcus visual area (CSv), but not in visual area V6. The results suggest that cross-modal convergence of cues to self-motion occurs in both hMST and CSv.

  9. Therapeutic hypothermia and reliability of somatosensory evoked potentials in predicting outcome after cardiopulmonary arrest.

    PubMed

    Rothstein, Ted Laurence

    2012-08-01

    The loss of the N20 component on testing median somatosensory evoked potentials (SSEP) has been established as the most reliable indicator of unfavorable prognosis in post-cardiopulmonary arrest patients. With the intervention of therapeutic hypothermia in the management of patients who remain comatose following cardiopulmonary arrest that association is now in dispute. Abandoning SSEP as a key prognostic indicator of neurologic outcome would be a serious loss and cannot be justified.

  10. Palliation of recurrent Ewing sarcoma of the pelvis with cryoablation and somatosensory-evoked potentials.

    PubMed

    Lessard, Anne-Marie I; Gilchrist, James; Schaefer, Leah; Dupuy, Damian E

    2009-01-01

    Palliation of recurrent Ewing sarcoma can be difficult to treat due to tumor resistance to chemotherapy and previously received maximum dose radiotherapy. We report the successful use of cryoablation for pain palliation in a patient with recurrent pelvic Ewing sarcoma. Tumor location necessitated use of somatosensory-evoked potentials to prevent nerve damage to the S1 nerve root. Clinical and imaging aspects of the case are discussed.

  11. 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.

  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.

  13. 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.

  14. 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

  15. Distributed functions of detection and discrimination of vibrotactile stimuli in the hierarchical human somatosensory system.

    PubMed

    Kim, Junsuk; Müller, Klaus-Robert; Chung, Yoon Gi; Chung, Soon-Cheol; Park, Jang-Yeon; Bülthoff, Heinrich H; Kim, Sung-Phil

    2014-01-01

    According to the hierarchical view of human somatosensory network, somatic sensory information is relayed from the thalamus to primary somatosensory cortex (S1), and then distributed to adjacent cortical regions to perform further perceptual and cognitive functions. Although a number of neuroimaging studies have examined neuronal activity correlated with tactile stimuli, comparatively less attention has been devoted toward understanding how vibrotactile stimulus information is processed in the hierarchical somatosensory cortical network. To explore the hierarchical perspective of tactile information processing, we studied two cases: (a) discrimination between the locations of finger stimulation; and (b) detection of stimulation against no stimulation on individual fingers, using both standard general linear model (GLM) and searchlight multi-voxel pattern analysis (MVPA) techniques. These two cases were studied on the same data set resulting from a passive vibrotactile stimulation experiment. Our results showed that vibrotactile stimulus locations on fingers could be discriminated from measurements of human functional magnetic resonance imaging (fMRI). In particular, it was in case (a) we observed activity in contralateral posterior parietal cortex (PPC) and supramarginal gyrus (SMG) but not in S1, while in case; (b) we found significant cortical activations in S1 but not in PPC and SMG. These discrepant observations suggest the functional specialization with regard to vibrotactile stimulus locations, especially, the hierarchical information processing in the human somatosensory cortical areas. Our findings moreover support the general understanding that S1 is the main sensory receptive area for the sense of touch, and adjacent cortical regions (i.e., PPC and SMG) are in charge of a higher level of processing and may thus contribute most for the successful classification between stimulated finger locations.

  16. Input management of production systems.

    PubMed

    Odum, E P

    1989-01-13

    Nonpoint sources of pollution, which are largely responsible for stressing regional and global life-supporting atmosphere, soil, and water, can only be reduced (and ultimately controlled) by input management that involves increasing the efficiency of production systems and reducing the inputs of environmentally damaging materials. Input management requires a major change, an about-face, in the approach to management of agriculture, power plants, and industries because the focus is on waste reduction and recycling rather than on waste disposal. For large-scale ecosystem-level situations a top-down hierarchical approach is suggested and illustrated by recent research in agroecology and landscape ecology.

  17. A systematic analysis of neurons with large somatosensory receptive fields covering multiple body regions in the secondary somatosensory area of macaque monkeys

    PubMed Central

    Toda, T.; Hihara, S.; Tanaka, M.; Iriki, A.; Iwamura, Y.

    2016-01-01

    Previous neurophysiological studies performed in macaque monkeys have revealed complex somatosensory responses in the secondary somatosensory area (SII), such as large receptive fields (RFs), as well as bilateral ones. However, systematic analyses of neurons with large RFs have not been performed. In the present study, we recorded single-unit activities in SII of awake macaque monkeys to investigate systematically large RFs by dividing the whole body into four body regions (head, trunk, forelimb, and hindlimb). Recorded neurons were classified into two types, according to whether the RFs were confined to one body region: single (n = 817) and combined (n = 282) body-region types. These two types were distinct in terms of the percentage of bilateral RFs: 55% in the single-region type and 90% in the combined type, demonstrating that two types of RF enlargement occur simultaneously in the combined type, namely, RF convergence from different body regions and RF convergence from both hemibodies. Among the combined-type RFs, two tendencies of RF convergence were found: 1) the distal parts of the limbs (i.e., hand and foot) and the mouth are interconnected, and 2) the trunk RFs extend continuously toward the distal parts of the limb and head to cover the entire body surface. Our distribution analysis on unfolded maps clarified that neurons having RFs with these two tendencies were distributed within specific subregions in SII. PMID:27559139

  18. Dual adaptive control: Design principles and applications

    NASA Technical Reports Server (NTRS)

    Mookerjee, Purusottam

    1988-01-01

    The design of an actively adaptive dual controller based on an approximation of the stochastic dynamic programming equation for a multi-step horizon is presented. A dual controller that can enhance identification of the system while controlling it at the same time is derived for multi-dimensional problems. This dual controller uses sensitivity functions of the expected future cost with respect to the parameter uncertainties. A passively adaptive cautious controller and the actively adaptive dual controller are examined. In many instances, the cautious controller is seen to turn off while the latter avoids the turn-off of the control and the slow convergence of the parameter estimates, characteristic of the cautious controller. The algorithms have been applied to a multi-variable static model which represents a simplified linear version of the relationship between the vibration output and the higher harmonic control input for a helicopter. Monte Carlo comparisons based on parametric and nonparametric statistical analysis indicate the superiority of the dual controller over the baseline controller.

  19. 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.

  20. 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

  1. Behavioural and neurofunctional impact of transcranial direct current stimulation on somatosensory learning.

    PubMed

    Hilgenstock, Raphael; Weiss, Thomas; Huonker, Ralph; Witte, Otto W

    2016-04-01

    We investigated the effect of repeated delivery of anodal transcranial direct current stimulation (tDCS) on somatosensory performance and long-term learning. Over the course of five days, tDCS was applied to the primary somatosensory cortex (S1) by means of neuronavigation employing magnetencephalography (MEG). Compared to its sham application, tDCS promoted tactile learning by reducing the two-point discrimination threshold assessed by the grating orientation task (GOT) primarily by affecting intersessional changes in performance. These results were accompanied by alterations in the neurofunctional organization of the brain, as revealed by functional magnetic resonance imaging conducted prior to the study, at the fifth day of tDCS delivery and four weeks after the last application of tDCS. A decrease in activation at the primary site of anodal tDCS delivery in the left S1 along retention of superior tactile acuity was observed at follow-up four weeks after the application of tDCS. Thus, we demonstrate long-term effects that repeated tDCS imposes on somatosensory functioning. This is the first study to provide insight into the mode of operation of tDCS on the brain's response to long-term perceptual learning, adding an important piece of evidence from the domain of non-invasive brain stimulation to show that functional changes detectable by fMRI in primary sensory cortices participate in perceptual learning.

  2. Seeing is not feeling: posterior parietal but not somatosensory cortex engagement during touch observation.

    PubMed

    Chan, Annie W-Y; Baker, Chris I

    2015-01-28

    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.

  3. Image-guided transcranial focused ultrasound stimulates human primary somatosensory cortex.

    PubMed

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

    2015-03-04

    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.

  4. 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.

  5. 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.

  6. Suppression of vibrotactile discrimination by transcranial magnetic stimulation of primary somatosensory cortex.

    PubMed

    Morley, J W; Vickery, R M; Stuart, M; Turman, A B

    2007-08-01

    A number of human and animal studies have reported a differential representation of the frequency of vibrotactile stimuli in the somatosensory cortices: neurons in the primary somatosensory cortex (SI) are predominantly responsive to lower frequencies of tactile vibration, and those in the secondary somatosensory cortex (SII) are predominantly responsive to higher frequencies. We employed transcranial magnetic stimulation (TMS) over SI in human subjects to investigate the extent to which the inactivation of SI disrupted the discrimination of vibrotactile stimulation at frequencies that give rise to the tactile sensations of flutter (30 Hz) and vibration (200 Hz). Frequency discrimination around the 30-Hz standard following application of TMS to SI was reduced in seven of the eight subjects, and around the 200-Hz standard was reduced in all eight subjects. The average change in discrimination following TMS was about 20% for both low and high frequencies of vibrotactile stimulation. These data suggest that disruption of SI: (1) has a direct effect on the discrimination of both low and high frequencies of vibrotactile stimuli, consistent with a serial model of processing, or (2) has a direct effect on low-frequency vibrotactile stimuli and an indirect effect on the processing of high-frequency vibrotactile stimuli by SII via cortico-cortical connections between the two regions.

  7. Bilateral connectivity in the somatosensory region using near-infrared spectroscopy (NIRS) by wavelet coherence

    NASA Astrophysics Data System (ADS)

    Fernandez Rojas, Raul; Huang, Xu; Ou, Keng-Liang

    2016-12-01

    Near-infrared spectroscopy (NIRS) has been used in medical imaging to obtain oxygenation and hemodynamic response in the cerebral cortex. This technique has been applied in cortical activation detection and functional connectivity in brain research. Despite some advances in functional connectivity, most of the studies have focused on the prefrontal cortex and little has been done to study the somatosensory region (S1). For that reason, the aim of our present study is to assess bilateral connectivity in the somatosensory region by using NIRS and noxious stimulation. Eleven healthy subjects were investigated using near-infrared spectroscopy during an acupuncture stimulation procedure to safely induce pain in subjects. A multiscale analysis based on wavelet transform coherence (WTC) was designed to assess the functional connectivity of corresponding channel pairs within the left and right s1 region. The cortical activation in the somatosensory region was higher after the acupuncture stimulation, which was consistent with similar studies. The coherence in time-frequency domain between homologous signals generated by contralateral channel pairs revealed two main periods (3.2 s and 12.8 s) with high coherence. Based on the WTC analysis, it was also found that the coherence increase in these periods was task-related. This study contributes to the research field to investigate cerebral hemodynamic response of pain perception using NIRS and demonstrates the use of wavelet transform as a method to investigate functional lateralization in the cerebral cortex.

  8. Abnormal Somatosensory Synchronization in Patients With Paroxysmal Kinesigenic Dyskinesia: A Magnetoencephalographic Study.

    PubMed

    Hsiao, Fu-Jung; Hsu, Wan-Yu; Chen, Wei-Ta; Chen, Rou-Shayn; Lin, Yung-Yang

    2016-08-11

    Paroxysmal kinesigenic dyskinesia (PKD) is a rare group of hyperkinetic movement disorders characterized by brief attacks of choreoathetosis or dystonia. To clarify the alterations of the functional connectivity within the somatosensory network in PKD patients, magnetoencephalographic (MEG) responses to paired median-nerve electrical stimulation were recorded in 10 PKD patients treated by carbamazepine or oxcarbamazepine and 22 age-matched controls. In patients, MEG recordings were obtained during drug-on and -off periods. Source-based functional connectivity analysis was performed between contralateral primary (cSI) and secondary (cSII), and ipsilateral secondary (iSII) somatosensory areas. During drug-off periods, patients with PKD demonstrated decreased cSI-iSII and increased cSII-iSII somatosensory connectivity at theta band. Drug-on periods lowered the functional connectivity in cSI-cSII at alpha and beta bands and in cSII-iSII at theta band compared with the drug-off periods. We suggest that altered theta functional connectivity in cSI-iSII and cSII-iSII could be the neurophysiological signatures in PKD.

  9. Common Coding and Dynamic Interactions Between Observed, Imagined, and Experienced Motor and Somatosensory Activity

    PubMed Central

    Case, Laura K; Pineda, Jaime; Ramachandran, Vilayanur S

    2015-01-01

    Motor imagery and perception- considered generally as forms of motor simulation- share overlapping neural representations with motor production. While much research has focused on the extent of this “common coding,” less attention has been paid to how these overlapping representations interact. How do imagined, observed, or produced actions influence one another, and how do we maintain control over our perception and behavior? In the first part of this review we describe interactions between motor production and motor simulation, and explore apparent regulatory mechanisms that balance these processes. Next, we consider the somatosensory system. Numerous studies now support a “sensory mirror system” comprised of neural representations activated by either afferent sensation or vicarious sensation. In the second part of this review we summarize evidence for shared representations of sensation and sensory simulation (including imagery and observed sensation), and suggest that similar interactions and regulation of simulation occur in the somatosensory domain as in the motor domain. We suggest that both motor and somatosensory simulations are flexibly regulated to support simulations congruent with our sensorimotor experience and goals and suppress or separate the influence of those that are not. These regulatory mechanisms are frequently revealed by cases of brain injury but can also be employed to facilitate sensorimotor rehabilitation. PMID:25863237

  10. 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.

  11. 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.

  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. System monitors discrete computer inputs

    NASA Technical Reports Server (NTRS)

    Burns, J. J.

    1966-01-01

    Computer system monitors inputs from checkout devices. The comparing, addressing, and controlling functions are performed in the I/O unit. This leaves the computer main frame free to handle memory, access priority, and interrupt instructions.

  14. Line scanning fMRI reveals earlier onset of optogenetically evoked BOLD response in rat somatosensory cortex as compared to sensory stimulation.

    PubMed

    Albers, Franziska; Schmid, Florian; Wachsmuth, Lydia; Faber, Cornelius

    2016-12-21

    The combination of optogenetic control and fMRI readout in the brain is increasingly used to assess neuronal networks and underlying signal processing. However, how exactly optogenetic activation or inhibition reproduces normal physiological input has not been fully unraveled. To assess details of temporal dynamics of the hemodynamic response, temporal resolution in rodent fMRI is often not sufficient. Recent advances in human fMRI using faster acquisition schemes cannot be easily translated to small animals due to smaller dimensions, fast physiological motion, and higher sensitivity to artefacts. Here, we applied a one dimensional line scanning acquisition with 50ms temporal resolution in rat somatosensory cortex. We observed that optogenetic activation reproduces the hemodynamic response upon sensory stimulation, but shows a 160 to 340ms earlier onset of the response. This difference is explained by direct activation of all opsin-expressing and illuminated cortical layers, while hemodynamic response to sensory stimulation is delayed during intracortical transmission between cortical layers. Our results confirm that optogenetic activation is a valid model for physiological neuronal input, and that differences in temporal behavior of only a few hundred milliseconds can be resolved in rodent fMRI.

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

    PubMed

    Maeda, Yumi; 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

    2014-06-01

    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

  16. 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

  17. 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

  18. Rewiring the primary somatosensory cortex in carpal tunnel syndrome with acupuncture.

    PubMed

    Maeda, Yumi; Kim, Hyungjun; Kettner, Norman; Kim, Jieun; Cina, Stephen; Malatesta, Cristina; Gerber, Jessica; McManus, Claire; Ong-Sutherland, Rebecca; Mezzacappa, Pia; Libby, Alexandra; Mawla, Ishtiaq; Morse, Leslie R; Kaptchuk, Ted J; Audette, Joseph; Napadow, Vitaly

    2017-03-02

    Carpal tunnel syndrome is the most common entrapment neuropathy, affecting the median nerve at the wrist. Acupuncture is a minimally-invasive and conservative therapeutic option, and while rooted in a complex practice ritual, acupuncture overlaps significantly with many conventional peripherally-focused neuromodulatory therapies. However, the neurophysiological mechanisms by which acupuncture impacts accepted subjective/psychological and objective/physiological outcomes are not well understood. Eligible patients (n = 80, 65 female, age: 49.3 ± 8.6 years) were enrolled and randomized into three intervention arms: (i) verum electro-acupuncture 'local' to the more affected hand; (ii) verum electro-acupuncture at 'distal' body sites, near the ankle contralesional to the more affected hand; and (iii) local sham electro-acupuncture using non-penetrating placebo needles. Acupuncture therapy was provided for 16 sessions over 8 weeks. Boston Carpal Tunnel Syndrome Questionnaire assessed pain and paraesthesia symptoms at baseline, following therapy and at 3-month follow-up. Nerve conduction studies assessing median nerve sensory latency and brain imaging data were acquired at baseline and following therapy. Functional magnetic resonance imaging assessed somatotopy in the primary somatosensory cortex using vibrotactile stimulation over three digits (2, 3 and 5). While all three acupuncture interventions reduced symptom severity, verum (local and distal) acupuncture was superior to sham in producing improvements in neurophysiological outcomes, both local to the wrist (i.e. median sensory nerve conduction latency) and in the brain (i.e. digit 2/3 cortical separation distance). Moreover, greater improvement in second/third interdigit cortical separation distance following verum acupuncture predicted sustained improvements in symptom severity at 3-month follow-up. We further explored potential differential mechanisms of local versus distal acupuncture using diffusion tensor

  19. Dual laser gyro test program

    NASA Astrophysics Data System (ADS)

    Jones, Malcolm E.; Moore, Kim Eric

    This paper addresses the results of a comparative test evaluation of two similar-sized but otherwise dissimilar ring laser gyroscopes (RLG's). Both units were tested side by side, with the input axes (IA's) parallel, on the same test table. This report describes the rationale and design factors considered important to the test objectives. Emphasis was placed upon the evaluation of the scale factor (SF) linearity, drift rate stability (short term and long term), and derived rate. Conclusions drawn were (1) that dual operation had an observable but insignificant effect on the test results, (2) that the benefits of dual operation outweighed the additional design and analysis efforts required at the outset of the program, and (3) that the performance characteristics of the two test articles were significantly different. The differences between the two test articles (1) led to suggestions which could direct one vendor toward obtaining improved performance and (2) resulted in the creation of a conceptually new method (DELTA TIME-COUNT histogram) for quickly assessing the quality of laser gyros (or any digital sensor device for that matter).

  20. Dual Enrollment Academy Programs

    ERIC Educational Resources Information Center

    Gonzalez, Nicolas; Chavez, Guadalupe

    2009-01-01

    Dual Enrollment Engineering (DEEA) and Medical Science (DEMSA) Academies are two-year dual enrollment programs for high school students. Students explore engineering and medical careers through college coursework. Students prepare for higher education in engineering and medical fields while completing associate degrees in biology or engineering…

  1. Single trial somatosensory evoked potential extraction with ARX filtering for a combined spinal cord intraoperative neuromonitoring technique

    PubMed Central

    Rossi, Lorenzo; Bianchi, Anna Maria; Merzagora, Anna; Gaggiani, Alberto; Cerutti, Sergio; Bracchi, Francesco

    2007-01-01

    Background When spinal cord functional integrity is at risk during surgery, intraoperative neuromonitoring is recommended. Tibial Single Trial Somatosensory Evoked Potentials (SEPs) and H-reflex are here used in a combined neuromonitoring method: both signals monitor the spinal cord status, though involving different nervous pathways. However, SEPs express a trial-to-trial variability that is difficult to track because of the intrinsic low signal-to-noise ratio. For this reason single trial techniques are needed to extract SEPs from the background EEG. Methods The analysis is performed off line on data recorded in eight scoliosis surgery sessions during which the spinal cord was simultaneously monitored through classical SEPs and H-reflex responses elicited by the same tibial nerve electrical stimulation. The single trial extraction of SEPs from the background EEG is here performed through AutoRegressive filter with eXogenous input (ARX). The electroencephalographic recording can be modeled as the sum of the background EEG, which can be described as an autoregressive process not related to the stimulus, and the evoked potential (EP), which can be viewed as a filtered version of a reference signal related to the stimulus. The choice of the filter optimal orders is based on the Akaike Information Criterion (AIC). The reference signal used as exogenous input in the ARX model is a weighted average of the previous SEPs trials with exponential forgetting behavior. Results The moving average exponentially weighted, used as reference signal for the ARX model, shows a better sensibility than the standard moving average in tracking SEPs fast inter-trial changes. The ability to promptly detect changes allows highlighting relations between waveform changes and surgical maneuvers. It also allows a comparative study with H-reflex trends: in particular, the two signals show different fall and recovery dynamics following stressful conditions for the spinal cord. Conclusion The ARX

  2. Segregation of Tactile Input Features in Neurons of the Cuneate Nucleus

    PubMed Central

    Jörntell, Henrik; Bengtsson, Fredrik; Geborek, Pontus; Spanne, Anton; Terekhov, Alexander V.; Hayward, Vincent

    2014-01-01

    Summary Our tactile perception of external objects depends on skin-object interactions. The mechanics of contact dictates the existence of fundamental spatiotemporal input features—contact initiation and cessation, slip, and rolling contact—that originate from the fact that solid objects do not interpenetrate. However, it is unknown whether these features are represented within the brain. We used a novel haptic interface to deliver such inputs to the glabrous skin of finger/digit pads and recorded from neurons of the cuneate nucleus (the brain’s first level of tactile processing) in the cat. Surprisingly, despite having similar receptive fields and response properties, each cuneate neuron responded to a unique combination of these inputs. Hence, distinct haptic input features are encoded already at subcortical processing stages. This organization maps skin-object interactions into rich representations provided to higher cortical levels and may call for a re-evaluation of our current understanding of the brain’s somatosensory systems. PMID:25175880

  3. Dual-tasking alleviated sleep deprivation disruption in visuomotor tracking: An fMRI study

    PubMed Central

    Gazes, Yunglin; Rakitin, Brian C.; Steffener, Jason; Habeck, Christian; Butterfield, Brady; Basner, Robert C.; Ghez, Claude; Stern, Yaakov

    2012-01-01

    Effects of dual-responding on tracking performance after 49-hr of sleep deprivation (SD) were evaluated behaviorally and with functional magnetic resonance imaging (fMRI). Continuous visuomotor tracking was performed simultaneously with an intermittent color-matching visual detection task in which a pair of color-matched stimuli constituted a target and non-matches were non-targets. Tracking error means were binned time-locked to stimulus onset of the detection task in order to observe changes associated with dual-responding by comparing the error during targets and non-targets. Similar comparison was made with fMRI data. Our result showed that despite a significant increase in the overall tracking error post SD, from 20 pixels pre SD to 45 pixels post SD, error decreased to a minimum of about 25 pixels 0 to 6 s after dual-response. Despite an overall reduced activation post SD, greater activation difference between targets and non-targets was found post SD in task-related regions, such as the left cerebellum, the left somatosensory cortex, the left extrastriate cortex, bilateral precuneus, the left middle frontal gyrus, and the left motor cortex. Our results suggest that dual-response helps to alleviate performance impairment usually associated with SD. The duration of the alleviation effect was on the order of seconds after dual-responding. PMID:22305924

  4. Input Type and Parameter Resetting: Is Naturalistic Input Necessary?

    ERIC Educational Resources Information Center

    Rothman, Jason; Iverson, Michael

    2007-01-01

    It has been argued that extended exposure to naturalistic input provides L2 learners with more of an opportunity to converge of target morphosyntactic competence as compared to classroom-only environments, given that the former provide more positive evidence of less salient linguistic properties than the latter (e.g., Isabelli 2004). Implicitly,…

  5. Mass exchange processes with input

    NASA Astrophysics Data System (ADS)

    Krapivsky, P. L.

    2015-05-01

    We investigate a system of interacting clusters evolving through mass exchange and supplemented by input of small clusters. Three possibilities depending on the rate of exchange generically occur when input is homogeneous: continuous growth, gelation, and instantaneous gelation. We mostly study the growth regime using scaling methods. An exchange process with reaction rates equal to the product of reactant masses admits an exact solution which allows us to justify the validity of scaling approaches in this special case. We also investigate exchange processes with a localized input. We show that if the diffusion coefficients are mass-independent, the cluster mass distribution becomes stationary and develops an algebraic tail far away from the source.

  6. Brain activation during dual-task processing is associated with cardiorespiratory fitness and performance in older adults

    PubMed Central

    Wong, Chelsea N.; Chaddock-Heyman, Laura; Voss, Michelle W.; Burzynska, Agnieszka Z.; Basak, Chandramallika; Erickson, Kirk I.; Prakash, Ruchika S.; Szabo-Reed, Amanda N.; Phillips, Siobhan M.; Wojcicki, Thomas; Mailey, Emily L.; McAuley, Edward; Kramer, Arthur F.

    2015-01-01

    Higher cardiorespiratory fitness is associated with better cognitive performance and enhanced brain activation. Yet, the extent to which cardiorespiratory fitness-related brain activation is associated with better cognitive performance is not well understood. In this cross-sectional study, we examined whether the association between cardiorespiratory fitness and executive function was mediated by greater prefrontal cortex activation in healthy older adults. Brain activation was measured during dual-task performance with functional magnetic resonance imaging in a sample of 128 healthy older adults (59–80 years). Higher cardiorespiratory fitness was associated with greater activation during dual-task processing in several brain areas including the anterior cingulate and supplementary motor cortex (ACC/SMA), thalamus and basal ganglia, right motor/somatosensory cortex and middle frontal gyrus, and left somatosensory cortex, controlling for age, sex, education, and gray matter volume. Of these regions, greater ACC/SMA activation mediated the association between cardiorespiratory fitness and dual-task performance. We provide novel evidence that cardiorespiratory fitness may support cognitive performance by facilitating brain activation in a core region critical for executive function. PMID:26321949

  7. DUAL PATHWAYS FOR HAPTIC AND VISUAL PERCEPTION OF SPATIAL AND TEXTURE INFORMATION

    PubMed Central

    Sathian, K.; Lacey, Simon; Stilla, Randall; Gibson, Gregory O.; Deshpande, Gopikrishna; Hu, Xiaoping; LaConte, Stephen; Glielmi, Christopher

    2011-01-01

    Segregation of information flow along a dorsally directed pathway for processing object location and a ventrally directed pathway for processing object identity is well established in the visual and auditory systems, but is less clear in the somatosensory system. We hypothesized that segregation of location vs. identity information in touch would be evident if texture is the relevant property for stimulus identity, given the salience of texture for touch. Here, we used functional magnetic resonance imaging (fMRI) to investigate whether the pathways for haptic and visual processing of location and texture are segregated, and the extent of bisensory convergence. Haptic texture-selectivity was found in the parietal operculum and posterior visual cortex bilaterally, and in parts of left inferior frontal cortex. There was bisensory texture-selectivity at some of these sites in posterior visual and left inferior frontal cortex. Connectivity analyses demonstrated, in each modality, flow of information from unisensory non-selective areas to modality-specific texture-selective areas and further to bisensory texture-selective areas. Location-selectivity was mostly bisensory, occurring in dorsal areas, including the frontal eye fields and multiple regions around the intraparietal sulcus bilaterally. Many of these regions received input from unisensory areas in both modalities. Together with earlier studies, the activation and connectivity analyses of the present study establish that somatosensory processing flows into segregated pathways for location and object identity information. The location-selective somatosensory pathway converges with its visual counterpart in dorsal frontoparietal cortex, while the texture-selective somatosensory pathway runs through the parietal operculum before converging with its visual counterpart in visual and frontal cortex. Both segregation of sensory processing according to object property and multisensory convergence appear to be universal

  8. Delta opioid receptors presynaptically regulate cutaneous mechanosensory neuron input to the spinal cord dorsal horn.

    PubMed

    Bardoni, Rita; Tawfik, Vivianne L; Wang, Dong; François, Amaury; Solorzano, Carlos; Shuster, Scott A; Choudhury, Papiya; Betelli, Chiara; Cassidy, Colleen; Smith, Kristen; de Nooij, Joriene C; Mennicken, Françoise; O'Donnell, Dajan; Kieffer, Brigitte L; Woodbury, C Jeffrey; Basbaum, Allan I; MacDermott, Amy B; Scherrer, Grégory

    2014-03-19

    Cutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity.

  9. Dual Credit/Dual Enrollment and Data Driven Policy Implementation

    ERIC Educational Resources Information Center

    Lichtenberger, Eric; Witt, M. Allison; Blankenberger, Bob; Franklin, Doug

    2014-01-01

    The use of dual credit has been expanding rapidly. Dual credit is a college course taken by a high school student for which both college and high school credit is given. Previous studies provided limited quantitative evidence that dual credit/dual enrollment is directly connected to positive student outcomes. In this study, predictive statistics…

  10. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  11. Optimal Inputs for System Identification.

    DTIC Science & Technology

    1995-09-01

    The derivation of the power spectral density of the optimal input for system identification is addressed in this research. Optimality is defined in...identification potential of general System Identification algorithms, a new and efficient System Identification algorithm that employs Iterated Weighted Least

  12. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  13. The advanced LIGO input optics

    NASA Astrophysics Data System (ADS)

    Mueller, Chris L.; Arain, Muzammil A.; Ciani, Giacomo; DeRosa, Ryan. T.; Effler, Anamaria; Feldbaum, David; Frolov, Valery V.; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J.; Kokeyama, Keiko; Korth, William Z.; Martin, Rodica M.; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H.; Tanner, David B.; Vorvick, Cheryl; Williams, Luke F.; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  14. Lab Inputs for Common Micros.

    ERIC Educational Resources Information Center

    Tinker, Robert

    1984-01-01

    The game paddle inputs of Apple microcomputers provide a simple way to get laboratory measurements into the computer. Discusses these game paddles and the necessary interface software. Includes schematics for Apple built-in paddle electronics, TRS-80 game paddle I/O, Commodore circuit for user port, and bus interface for Sinclair/Timex, Commodore,…

  15. The advanced LIGO input optics

    SciTech Connect

    Mueller, Chris L. Arain, Muzammil A.; Ciani, Giacomo; Feldbaum, David; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Martin, Rodica M.; Reitze, David H.; Tanner, David B.; Williams, Luke F.; Mueller, Guido; DeRosa, Ryan T.; Effler, Anamaria; Kokeyama, Keiko; Frolov, Valery V.; Mullavey, Adam; Kawabe, Keita; Vorvick, Cheryl; King, Eleanor J.; and others

    2016-01-15

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  16. Signal Prediction With Input Identification

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Chen, Ya-Chin

    1999-01-01

    A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

  17. 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.

  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

    2013-11-06

    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. Comparing development of synaptic proteins in rat visual, somatosensory, and frontal cortex.

    PubMed

    Pinto, Joshua G A; Jones, David G; Murphy, Kathryn M

    2013-01-01

    Two theories have influenced our understanding of cortical development: the integrated network theory, where synaptic development is coordinated across areas; and the cascade theory, where the cortex develops in a wave-like manner from sensory to non-sensory areas. These different views on cortical development raise challenges for current studies aimed at comparing detailed maturation of the connectome among cortical areas. We have taken a different approach to compare synaptic development in rat visual, somatosensory, and frontal cortex by measuring expression of pre-synaptic (synapsin and synaptophysin) proteins that regulate vesicle cycling, and post-synaptic density (PSD-95 and Gephyrin) proteins that anchor excitatory or inhibitory (E-I) receptors. We also compared development of the balances between the pairs of pre- or post-synaptic proteins, and the overall pre- to post-synaptic balance, to address functional maturation and emergence of the E-I balance. We found that development of the individual proteins and the post-synaptic index overlapped among the three cortical areas, but the pre-synaptic index matured later in frontal cortex. Finally, we applied a neuroinformatics approach using principal component analysis and found that three components captured development of the synaptic proteins. The first component accounted for 64% of the variance in protein expression and reflected total protein expression, which overlapped among the three cortical areas. The second component was gephyrin and the E-I balance, it emerged as sequential waves starting in somatosensory, then frontal, and finally visual cortex. The third component was the balance between pre- and post-synaptic proteins, and this followed a different developmental trajectory in somatosensory cortex. Together, these results give the most support to an integrated network of synaptic development, but also highlight more complex patterns of development that vary in timing and end point among the

  20. Prominent activation of the intraparietal and somatosensory areas during angle discrimination by intra-active touch.

    PubMed

    Yang, Jiajia; Han, Hongbin; Chui, Dehua; Shen, Yong; Wu, Jinglong

    2012-12-01

    Intra-active touch (IAT) is a process that involves a body part doing the touching (active touch [AT]) and another body part being touched (passive touch [PT]) simultaneously. The brain representation related to IAT is still unclear. A total of 23 subjects carried out angle discrimination under PT, AT and IAT conditions with functional magnetic resonance imaging. All of the tasks were strictly dependent on cutaneous feedback from the finger(s). As the subjects were able to perceive the angle stimuli from the right (touching) and left (touched) sides during the IAT condition, we expected there would be greater brain activation with the IAT condition than for the AT or PT condition. Therefore, we hypothesized that the region within and/or around the intraparietal sulcus (IPS) and the part of the primary somatosensory cortex (SI) that is associated with high-level tactile spatial processing would be more active during the IAT task than during the AT and PT tasks. Compared with the areas activated by the motor somatosensory control task, the most prominent activation areas evoked by the three-angle discrimination tasks were in the SI and secondary somatosensory cortex areas in the bilateral parietal operculum, IPS, lateral occipital complex, insula and cerebellum. Finally, we directly compared IAT with AT and PT, and the results suggest that the contralateral part of IPS and part of the SI are more active under IAT conditions than under either AT or PT conditions. These results suggest that both hemispheres contribute to angle discrimination during IAT.

  1. 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

  2. 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

  3. 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

  4. Heart rate variability is encoded in the spontaneous discharge of thalamic somatosensory neurones in cat

    PubMed Central

    Massimini, Marcello; Porta, Alberto; Mariotti, Maurizio; Malliani, Alberto; Montano, Nicola

    2000-01-01

    We studied the spontaneous discharge variability of thalamocortical somatosensory neurones in the awake cat in order to disclose its possible information content. The presence of slow (0.09–1.39 Hz) regular fluctuations in the discharge rate of these cells during the waking state has been previously reported. Oscillations in a similar frequency range are known to characterize the activity of central and peripheral neurones pertaining to the autonomic nervous system and the variability of heart period (RR interval variability).A surrogate data test, performed on our database, confirmed the presence of slow (0.05–1 Hz) non-random fluctuations in firing rate.Linear regression detected the presence of an inverse relationship between the values of RR interval and the concurrent levels of neural discharge.Frequency domain analysis indicated that a significant coupling between the two variability signals preferentially occurred in two frequency bands: in the frequency of the respiratory sinus arrhythmia and in correspondence with a slower rhythm (0.07–0.3 Hz), the two signals being in phase opposition in most of the cases.Coherent fluctuations could also be observed when epochs of evoked activity were analysed, while coupling between the two variability signals appeared to be disrupted after sleep onset.We conclude that RR interval variability, an internally generated dynamic related to basic visceral regulation, is encoded in the discharge of single somatosensory thalamocortical neurones during wakefulness. A possible interaction with the transmission of somatosensory information has to be evaluated. PMID:10896727

  5. Somatosensory Evoked Field in Response to Visuotactile Stimulation in 3- to 4-Year-Old Children

    PubMed Central

    Remijn, Gerard B.; Kikuchi, Mitsuru; Shitamichi, Kiyomi; Ueno, Sanae; Yoshimura, Yuko; Nagao, Kikuko; Tsubokawa, Tsunehisa; Kojima, Haruyuki; Higashida, Haruhiro; Minabe, Yoshio

    2014-01-01

    A child-customized magnetoencephalography system was used to investigate somatosensory evoked field (SEF) in 3- to 4-year-old children. Three stimulus conditions were used in which the children received tactile-only stimulation to their left index finger or visuotactile stimulation. In the two visuotactile conditions, the children received tactile stimulation to their finger while they watched a video of tactile stimulation applied either to someone else’s finger (the finger-touch condition) or to someone else’s toe (the toe-touch condition). The latencies and source strengths of equivalent current dipoles (ECDs) over contralateral (right) somatosensory cortex were analyzed. In the preschoolers who provided valid ECDs, the stimulus conditions induced an early-latency ECD occurring between 60 and 68 ms mainly with an anterior direction. We further identified a middle-latency ECD between 97 and 104 ms, which predominantly had a posterior direction. Finally, initial evidence was found for a late-latency ECD at about 139–151 ms again more often with an anterior direction. Differences were found in the source strengths of the middle-latency ECDs among the stimulus conditions. For the paired comparisons that could be formed, ECD source strength was more pronounced in the finger-touch condition than in the tactile-only and the toe-touch conditions. Although more research is necessary to expand the data set, this suggests that visual information modulated preschool SEF. The finding that ECD source strength was higher when seen and felt touch occurred to the same body part, as compared to a different body part, might further indicate that connectivity between visual and tactile information is indexed in preschool somatosensory cortical activity, already in a somatotopic way. PMID:24715860

  6. Integration of auditory and somatosensory error signals in the neural control of speech movements.

    PubMed

    Feng, Yongqiang; Gracco, Vincent L; Max, Ludo

    2011-08-01

    We investigated auditory and somatosensory feedback contributions to the neural control of speech. In task I, sensorimotor adaptation was studied by perturbing one of these sensory modalities or both modalities simultaneously. The first formant (F1) frequency in the auditory feedback was shifted up by a real-time processor and/or the extent of jaw opening was increased or decreased with a force field applied by a robotic device. All eight subjects lowered F1 to compensate for the up-shifted F1 in the feedback signal regardless of whether or not the jaw was perturbed. Adaptive changes in subjects' acoustic output resulted from adjustments in articulatory movements of the jaw or tongue. Adaptation in jaw opening extent in response to the mechanical perturbation occurred only when no auditory feedback perturbation was applied or when the direction of adaptation to the force was compatible with the direction of adaptation to a simultaneous acoustic perturbation. In tasks II and III, subjects' auditory and somatosensory precision and accuracy were estimated. Correlation analyses showed that the relationships 1) between F1 adaptation extent and auditory acuity for F1 and 2) between jaw position adaptation extent and somatosensory acuity for jaw position were weak and statistically not significant. Taken together, the combined findings from this work suggest that, in speech production, sensorimotor adaptation updates the underlying control mechanisms in such a way that the planning of vowel-related articulatory movements takes into account a complex integration of error signals from previous trials but likely with a dominant role for the auditory modality.

  7. Bifocal dual reflector antenna

    NASA Technical Reports Server (NTRS)

    Rao, B. L. J.

    1973-01-01

    A bifocal dual reflector antenna is similar to and has better scan capability than classical cassegrain reflector antenna. The method used in determining the reflector surfaces is a modification of a design method for the dielectric bifocal lens. The three dimensional dual reflector is obtained by first designing an exact (in geometrical optics sense) two-point corrected two dimensional reflector and then rotating it around its axis of symmetry. A point by point technique is used in computing the reflector surfaces. Computed radiation characteristics of the dual reflector are compared with those of a cassegrain reflector. The results confirm that the bifocal antenna has superior performance.

  8. ’Short-Latency’ Somatosensory Evoked Potentials during Experimentally Induced Biodynamic Stress in Humans.

    DTIC Science & Technology

    1985-12-01

    BP, a negative-going * ."" near-field wave originating in the brachial plexus, the A and B waves of Chiappa , et a]. (1980), and the NI, N2, and P2...1981) and by Chiappa , et al. (1980). Table 2 shows the baseline means and standard deviations of the SSEP peaks for all five Ss, derived from the loose...Head and Spine. Charles Thomas, Springfield, 1982, 324-378. Chiappa , K.H., Choi, S.K. and Young, R.R. Short latency somatosensory evoked potentials

  9. 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.

  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. Aristotle's illusion reveals interdigit functional somatosensory alterations in focal hand dystonia.

    PubMed

    Tinazzi, Michele; Marotta, Angela; Fasano, Alfonso; Bove, Francesco; Bentivoglio, Anna Rita; Squintani, Giovanna; Pozzer, Lara; Fiorio, Mirta

    2013-03-01

    In focal hand dystonia, the cortical somatosensory representation of the fingers is abnormal, with overlapping receptive fields and reduced interdigit separation. These abnormalities are associated with deficits in sensory perception, as previously demonstrated by applying tactile stimuli to one finger at a time. What is still unknown is whether the sensory deficits can be observed when tactile perception involves more than one finger. To address this issue, we applied 'Aristotle's illusion' to 15 patients with focal hand dystonia, 15 patients with dystonia not affecting the hand (blepharospasm and cervical dystonia) and 15 healthy control subjects. In this illusion, one object touching the contact point of two crossed fingertips is perceived as two objects by a blindfolded subject. The same object placed between two parallel fingertips is correctly perceived as one. The illusory doubling sensation is because of the fact that the contact point between the crossed fingers consists of non-adjacent and functionally unrelated skin regions, which usually send sensory signals to separate spots in the somatosensory cortex. In our study, participants were touched by one sphere between the second-third digits, the second-fourth digits and the fourth-fifth digits of both hands, either in crossed or in parallel position, and had to refer whether they felt one or two stimuli. The percentage of 'two stimuli' responses was an index of the illusory doubling. Both healthy control subjects and dystonic patients presented Aristotle's illusion when the fingers were crossed. However, patients with focal hand dystonia presented a significant reduction of the illusion when the sphere was placed between the crossed fourth and fifth digits of the affected hand. This reduction correlated with the severity of motor disease at the fingers. Similar findings were not observed in non-hand dystonia and control groups. The reduction of Aristotle's illusion in non-affected fingers and its

  12. ISPMER: Integrated system for combined PET, MRI, and electrophysiological recording in somatosensory studies in rats

    NASA Astrophysics Data System (ADS)

    Shih, Yen-Yu; Chen, You-Yin; Chen, Jyh-Cheng; Chang, Chen; Jaw, Fu-Shan

    2007-10-01

    The present study developed an integrated system for use in combined PET, MRI, and electrophysiological recording in somatosensory studies in rats, called ISPMER. A stereotaxic frame was designed for animal positioning that could be used in all three measurement modalities, and its dimensions complied with the gold standard of the Paxinos and Watson rat brain atlas. A graphical user interface was developed for analyzing the data using several signal processing algorithms. This integrated system provides a novel interface for the recording and processing of three-dimensional neuronal signals in three modalities.

  13. Optical intrinsic signals in rat primary somatosensory cortex during non-noxious and noxious elecrical stimulation of the sciatic nerve

    NASA Astrophysics Data System (ADS)

    Luo, Weihua; Li, Pengcheng; Chen, Shangbin; Luo, Qingming

    2003-12-01

    Optical imaging method was applied into observing the temporal-spatial characteristic of rat primary somatosensory cortex during graded electrical stimulation of the sciatic nerve (5hz,duration of 2s,0.5ms puls,1x,10x and 20x muscle twitch threshold). We found that the temporal and spatial properties of hindlimb somatosensory cortex were modulated by graded intensity electrical stimulation of the sciatic nerve. The magnitude and time course were larger and longer with the intensity raising. And the spatial extent was wider at 20x stimulus than the other two kinds of stimulus. Therefore, our optical imaging was based on 570nm, which only reflect the changes of blood volume. Then our future study will reveal more information of pain modulation in primary somatosensory cortex.

  14. Kinematic mapping reveals different spatial distributions of center of pressure high-speed regions under somatosensory loss.

    PubMed

    Portela, Fellipe M; Ferreira, Arthur S

    2014-01-01

    The spatial distribution of center-of-pressure speed during postural tasks and its changes due to somatosensory constraint (temporary ischemic hypoxia on ankle/feet) were investigated in young, healthy subjects (n = 13). A single high-speed region in the central region of the statokinesigram was observed during postural tasks with full sensory information. A significant increase in the quantity of high-speed regions was observed during ischemia and somatosensory constraint, whereas a significant increase in the quantity of high-speed regions localized more distant to the center of center-of-pressure area occurred under somatosensory constraints, suggesting a redirection of center-of-pressure trajectory to adjust the position of the center of mass with respect to the egocentric reference of balance.

  15. Cooling of the cerebellar interpositus nucleus abolishes somatosensory cortical learning-related activity in eyeblink conditioned rabbits.

    PubMed

    Wikgren, Jan; Lavond, David G; Ruusuvirta, Timo; Korhonen, Tapani

    2006-06-03

    Nictitating membrane movement and multiple-unit activity in the somatosensory cortex were recorded from rabbits during paired (N=6) and unpaired (N=5) presentations of a tone conditioned stimulus (CS) and an airpuff unconditioned stimulus (US). A behavioural conditioned response (CR) to the CS and an accompanying neural response in the somatosensory cortex developed only in the paired group. Inactivation of the cerebellar interpositus nucleus abolished both the acquired CR and the accompanying neural response. However, the CS facilitated both behavioural and neural responses to the US during the inactivation. Thus, the absence of the CR could not be accounted for by the general inability of the CS to alter the behaviour constituting the CR or the activity of the somatosensory cortex. These findings suggest that the efferent copy of the signal related to the eyeblink CR is projected from the cerebellum to the cerebral cortical areas of the US modality.

  16. Systems and methods for reconfiguring input devices

    NASA Technical Reports Server (NTRS)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  17. Early and late activity in somatosensory cortex reflects changes in bodily self-consciousness: an evoked potential study.

    PubMed

    Aspell, J E; Palluel, E; Blanke, O

    2012-08-02

    How can we investigate the brain mechanisms underlying self-consciousness? Recent behavioural studies on multisensory bodily perception have shown that multisensory conflicts can alter bodily self-consciousness such as in the "full body illusion" (FBI) in which changes in self-identification with a virtual body and tactile perception are induced. Here we investigated whether experimental changes in self-identification during the FBI are accompanied by activity changes in somatosensory cortex by recording somatosensory-evoked potentials (SEPs). To modulate self-identification, participants were filmed by a video camera from behind while their backs were stroked, either synchronously (illusion condition) or asynchronously (control condition) with respect to the stroking seen on their virtual body. Tibial nerve SEPs were recorded during the FBI and analysed using evoked potential (EP) mapping. Tactile mislocalisation was measured using the crossmodal congruency task. SEP mapping revealed five sequential periods of brain activation during the FBI, of which two differed between the illusion condition and the control condition. Activation at 30-50 ms (corresponding to the P40 component) in primary somatosensory cortex was stronger in the illusion condition. A later activation at ∼110-200 ms, likely originating in higher-tier somatosensory regions in parietal cortex, was stronger and lasted longer in the control condition. These data show that changes in bodily self-consciousness modulate activity in primary and higher-tier somatosensory cortex at two distinct processing steps. We argue that early modulations of primary somatosensory cortex may be a consequence of (1) multisensory integration of synchronous vs. asynchronous visuo-tactile stimuli and/or (2) differences in spatial attention (to near or far space) between the conditions. The later activation in higher-tier parietal cortex (and potentially other regions in temporo-parietal and frontal cortex) likely

  18. 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

  19. Intracortical connections are altered after long-standing deprivation of dorsal column inputs in the hand region of area 3b in squirrel monkeys.

    PubMed

    Liao, Chia-Chi; Reed, Jamie L; Kaas, Jon H; Qi, Hui-Xin

    2016-05-01

    A complete unilateral lesion of the dorsal column somatosensory pathway in the upper cervical spinal cord deactivates neurons in the hand region in contralateral somatosensory cortex (areas 3b and 1). Over weeks to months of recovery, parts of the hand region become reactivated by touch on the hand or face. To determine whether changes in cortical connections potentially contribute to this reactivation, we injected tracers into electrophysiologically identified locations in cortex of area 3b representing the reactivated hand and normally activated face in adult squirrel monkeys. Our results indicated that even when only partially reactivated, most of the expected connections of area 3b remained intact. These intact connections include the majority of intrinsic connections within area 3b; feedback connections from area 1, secondary somatosensory cortex (S2), parietal ventral area (PV), and other cortical areas; and thalamic inputs from the ventroposterior lateral nucleus (VPL). In addition, tracer injections in the reactivated hand region of area 3b labeled more neurons in the face and shoulder regions of area 3b than in normal monkeys, and injections in the face region of area 3b labeled more neurons in the hand region. Unexpectedly, the intrinsic connections within area 3b hand cortex were more widespread after incomplete dorsal column lesions (DCLs) than after a complete DCL. Although these additional connections were limited, these changes in connections may contribute to the reactivation process after injuries. J. Comp. Neurol. 524:1494-1526, 2016. © 2015 Wiley Periodicals, Inc.

  20. Human Factors Engineering: Current and Emerging Dual-Use Applications

    NASA Technical Reports Server (NTRS)

    Chandlee, G. O.; Goldsberry, B. S.

    1994-01-01

    Human Factors Engineering is a multidisciplinary endeavor in which information pertaining to human characteristics is used in the development of systems and machines. Six representatives considered to be experts from the public and private sectors were surveyed in an effort to identify the potential dual-use of human factors technology. Each individual was asked to provide a rating as to the dual-use of 85 identified NASA technologies. Results of the survey were as follows: nearly 75 percent of the technologies were identified at least once as high dual-use by one of the six survey respondents, and nearly 25 percent of the identified NASA technologies were identified as high dual-use technologies by a majority of the respondents. The perceived level of dual-use appeared to be independent of the technology category. Successful identification of dual-use technology requires expanded input from industry. As an adjunct, cost-benefit analysis should be conducted to identify the feasibility of the dual-use technology. Concurrent with this effort should be an examination of precedents established by other technologies in other industrial settings. Advances in human factors and systems engineering are critical to reduce risk in any workplace and to enhance industrial competitiveness.

  1. National hospital input price index.

    PubMed

    Freeland, M S; Anderson, G; Schendler, C E

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 per cent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies.

  2. Functional connectivity and activity of white matter in somatosensory pathways under tactile stimulations.

    PubMed

    Wu, Xi; Yang, Zhipeng; Bailey, Stephen K; Zhou, Jiliu; Cutting, Laurie E; Gore, John C; Ding, Zhaohua

    2017-03-08

    Functional MRI has proven to be effective in detecting neural activity in brain cortices on the basis of blood oxygenation level dependent (BOLD) contrast, but has relatively poor sensitivity for detecting neural activity in white matter. To demonstrate that BOLD signals in white matter are detectable and contain information on neural activity, we stimulated the somatosensory system and examined distributions of BOLD signals in related white matter pathways. The temporal correlation profiles and frequency contents of BOLD signals were compared between stimulation and resting conditions, and between relevant white matter fibers and background regions, as well as between left and right side stimulations. Quantitative analyses show that, overall, MR signals from white matter fiber bundles in the somatosensory system exhibited significantly greater temporal correlations with the primary sensory cortex and greater signal power during tactile stimulations than in a resting state, and were stronger than corresponding measurements for background white matter both during stimulations and in a resting state. The temporal correlation and signal power under stimulation were found to be twice those observed from the same bundle in a resting state, and bore clear relations with the side of stimuli. These indicate that BOLD signals in white matter fibers encode neural activity related to their functional roles connecting cortical volumes, which are detectable with appropriate methods.

  3. Insula and somatosensory cortical myelination and iron markers underlie individual differences in empathy

    PubMed Central

    Allen, Micah; Frank, Darya; Glen, James C.; Fardo, Francesca; Callaghan, Martina F.; Rees, Geraint

    2017-01-01

    Empathy is a key component of our ability to engage and interact with others. In recent years, the neural mechanisms underlying affective and cognitive empathy have garnered intense interest. This work demonstrates that empathy for others depends upon a distributed network of regions such as the insula, parietal cortex, and somatosensory areas, which are also activated when we ourselves experience an empathized-with emotion (e.g., pain). Individuals vary markedly in their ability to empathize with others, which predicts the tendency to help others and relates to individual differences in the neuroanatomy of these areas. Here, we use a newly developed, high-resolution (800 μm isotropic), quantitative MRI technique to better elucidate the neuroanatomical underpinnings of individual differences in empathy. Our findings extend previous studies of the neuroanatomical correlates of cognitive and affective empathy. In particular, individual differences in cognitive empathy were associated with markers of myeloarchitectural integrity of the insular cortex, while affective empathy was predicted by a marker of iron content in second somatosensory cortex. These results indicate potential novel biomarkers of trait empathy, suggesting that microstructural features of an empathy and body-related network are crucial for understanding the mental and emotional states of others. PMID:28256532

  4. Motor imagery evokes increased somatosensory activity in Parkinson's disease patients with tremor.

    PubMed

    Helmich, Rick C; Bloem, Bastiaan R; Toni, Ivan

    2012-08-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and whether these differences relate to the cerebral circuit producing tremor. We compared 18 PD patients with marked tremor, 20 PD patients without tremor, and 19 healthy controls. Subjects performed a controlled motor imagery task during fMRI scanning. We quantified imagery-related cerebral activity by contrasting imagery of biomechanically difficult and easy movements. Tremor-related activity was identified by relating cerebral activity to fluctuations in tremor amplitude, using electromyography during scanning. PD patients with tremor had better behavioral performance than PD patients without tremor. Furthermore, tremulous PD patients showed increased imagery-related activity in somatosensory area 3a, as compared with both healthy controls and to nontremor PD patients. This effect was independent from tremor-related activity, which was localized to the motor cortex, cerebellum, and thalamic ventral intermediate nucleus (VIM). The VIM, with known projections to area 3a, was unique in showing both tremor- and imagery-related responses. We conclude that parkinsonian tremor influences motor imagery by modulating central somatosensory processing through the VIM. This mechanism may explain clinical differences between PD patients with and without tremor.

  5. Quality discrimination for noxious stimuli in secondary somatosensory cortex: a MEG-study.

    PubMed

    Maihöfner, Christian; Kaltenhäuser, Martin

    2009-11-01

    A complex cortical network is believed to encode the multi-dimensionality of the human pain experience. In the present study, we used magnetoencephalography (MEG) to examine whether the cortical processing of noxious stimuli with different psychophysical properties differs in primary (S1) and secondary (S2) somatosensory cortices. Noxious low (condition 1) and high (condition 2) current density stimulations of equal stimulus intensities were applied at the left forearm in 12 subjects in a randomised order. Concomitantly, subjects had to evaluate the corresponding sensory-discriminative and affective-motivational pain dimensions. MEG revealed an increased activation of bilateral secondary somatosensory cortices (S2) during condition 2 compared to condition 1. Higher activations of bilateral S2 were significantly correlated with higher scores for the sensory-discriminative component during condition 2. In contrast, corresponding scores for the affective-motivational pain dimension did not differ between both conditions. Therefore, concerning the sensory dimension of the human pain experience we conclude that the S2 cortex is involved in the encoding of quality discrimination.

  6. Visual–Somatosensory Integration is Linked to Physical Activity Level in Older Adults

    PubMed Central

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

    2016-01-01

    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. PMID:26152050

  7. Somatosensory Evoked Potentials in Patients with Hypoxic-Ischemic Brain Injury.

    PubMed

    Horn, Janneke; Tjepkema-Cloostermans, Marleen C

    2017-02-01

    Predicting the future of patients with hypoxic-ischemic encephalopathy after successful cardiopulmonary resuscitation is often difficult. Registration of the median nerve somatosensory evoked potential (SSEP) can assist in the neurologic evaluation in these patients. In this article, the authors discuss the principles, applications, and limitations of SSEP registration in the intensive care unit, with a focus on prognostication. Registration of the SSEP is a very reliable and reproducible method, if it is performed and interpreted correctly. During SSEP recordings, great care should be taken to improve the signal-to-noise ratio. If the noise level is too high, the peripheral responses are abnormal or the response is not reproducible in a second set of stimuli; therefore, interpretation of the SSEPs cannot be done reliably. A bilaterally absent cortical SSEP response is a very reliable predictor of poor neurologic outcome in patients with HIE. It has a high specificity, but a low sensitivity, indicating that present cortical responses are a weak predictor of a good recovery. Further research is being done to increase the sensitivity. Somatosensory evoked potentials can be used in a multimodal approach for prognostication of outcome.

  8. Transcranial magnetic stimulation over human secondary somatosensory cortex disrupts perception of pain intensity.

    PubMed

    Lockwood, Patricia L; Iannetti, Gian Domenico; Haggard, Patrick

    2013-09-01

    Pain is a complex sensory experience resulting from the activity of a network of brain regions. However, the functional contribution of individual regions in this network remains poorly understood. We delivered single-pulse transcranial magnetic stimulation (TMS) to the contralateral primary somatosensory cortex (S1), secondary somatosensory cortex (S2) and vertex (control site) 120 msec after selective stimulation of nociceptive afferents using neodymium:yttrium-aluminium-perovskite (Nd:YAP) laser pulses causing painful sensations. Participants were required to judge either the intensity (medium/high) or the spatial location (proximal/distal) of the stimulus in a two-alternative forced choice paradigm. When TMS pulses were delivered over S2, participants' ability to judge pain intensity was disrupted, as compared to S1 and vertex (control) stimulation. Signal-detection analysis demonstrated a loss of sensitivity to stimulation intensity, rather than a shift in perceived pain level or response bias. We did not find any effect of TMS on the ability to localise nociceptive stimuli on the skin. The novel finding that TMS over S2 can disrupt perception of pain intensity suggests a causal role for S2 in encoding of pain intensity.

  9. 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.

  10. Stochastic resonance in the spinal cord and somatosensory cortex of the cat

    NASA Astrophysics Data System (ADS)

    Manjarrez, Elias; Rojas-Piloni, Gerardo; Perez, Hugo; Mendez, Ignacio; Hernandez-Paxtian, Zulma; Flores, Amira

    2003-05-01

    The aim of this study was to demonstrate the occurrence of stochastic resonance (SR) in spinal and cortical potentials elicited by periodic tactile stimuli in the anaesthetised cat. The periodic tactile stimuli were applied on the central pad of the hindpaw and the noisy tactile stimuli on the glabrous skin of the third hindpaw digit. This protocol allowed that the signal and noise were mixed not in the skin but in the somatosensory regions of the central nervous system. The results show that a particular level of tactile noise can increase the amplitude of the spinal and cortical potentials elicited by periodic tactile stimuli. The topographical distribution of evoked potentials indicates that the effects of noise were spatially restricted. All cats showed distinct SR behavior at the spinal and cortical stages of the sensory encoding. Such SR was abolished in the cortical but not in the spinal recording after the sectioning of the ascending pathways. This suggests that the spinal neurones may also contribute to the SR observed at the cortical level. The present study documents the first evidence that the SR phenomenon occurs in the spinal and cortical somatosensory system itself and not only in the peripheral sensory receptors.

  11. Structure of a single whisker representation in layer 2 of mouse somatosensory cortex.

    PubMed

    Clancy, Kelly B; Schnepel, Philipp; Rao, Antara T; Feldman, Daniel E

    2015-03-04

    Layer (L)2 is a major output of primary sensory cortex that exhibits very sparse spiking, but the structure of sensory representation in L2 is not well understood. We combined two-photon calcium imaging with deflection of many whiskers to map whisker receptive fields, characterize sparse coding, and quantitatively define the point representation in L2 of mouse somatosensory cortex. Neurons within a column-sized imaging field showed surprisingly heterogeneous, salt-and-pepper tuning to many different whiskers. Single whisker deflection elicited low-probability spikes in highly distributed, shifting neural ensembles spanning multiple cortical columns. Whisker-evoked response probability correlated strongly with spontaneous firing rate, but weakly with tuning properties, indicating a spectrum of inherent responsiveness across pyramidal cells. L2 neurons projecting to motor and secondary somatosensory cortex differed in whisker tuning and responsiveness, and carried different amounts of information about columnar whisker deflection. From these data, we derive a quantitative, fine-scale picture of the distributed point representation in L2.

  12. A redefinition of somatosensory areas in the lateral sulcus of macaque monkeys.

    PubMed

    Krubitzer, L; Clarey, J; Tweedale, R; Elston, G; Calford, M

    1995-05-01

    The present investigation was designed to determine the organization of somatosensory fields in the lateral sulcus of macaque monkeys using standard microelectrode recording techniques. Our results provide evidence for two complete representations of the body surface. We term these fields the second somatosensory area (SII) and the parietal ventral area (PV) because of their similarities in position, internal organization, and relationship to anterior parietal fields, as described for SII and PV in other mammals. Areas SII and PV are mirror-symmetrical representations of the body surface, sharing a common boundary at the representations of the digits of the hand and foot, lips, and mouth. These fields are located adjacent to the face representations of anterior parietal fields (areas 3b, 1, and 2), and are bounded ventrally and caudally by other regions of cortex in which neurons are responsive to somatic or multimodal stimulation. The finding of a double representation of the body surface in the region of cortex traditionally designated as SII may explain conflicting descriptions of SII organization in macaque monkeys. In addition, the present study raises some questions regarding the designation of serial processing pathways in Old World monkeys, by suggesting that fields may have been confused in studies demonstrating such pathways. We propose that SII and PV are components of a common plan of organization, and are present in many eutherian mammals.

  13. Beta oscillations in the monkey sensorimotor network reflect somatosensory decision making

    PubMed Central

    Haegens, Saskia; Nácher, Verónica; Hernández, Adrián; Luna, Rogelio; Jensen, Ole; Romo, Ranulfo

    2011-01-01

    The neuronal correlate of perceptual decision making has been extensively studied in the monkey somatosensory system by using a vibrotactile discrimination task, showing that stimulus encoding, retention, and comparison are widely distributed across cortical areas. However, from a network perspective, it is not known what role oscillations play in this task. We recorded local field potentials (LFPs) from diverse cortical areas of the sensorimotor system while one monkey performed the vibrotactile discrimination task. Exclusively during stimulus presentation, a periodic response reflecting the stimulus frequency was observed in the somatosensory regions, suggesting that after initial processing, the frequency content of the stimulus is coded in some other way than entrainment. Interestingly, we found that oscillatory activity in the beta band reflected the dynamics of decision making in the monkey sensorimotor network. During the comparison and decision period, beta activity showed a categorical response that reflected the decision of the monkey and distinguished correct from incorrect responses. Importantly, this differential activity was absent in a control condition that involved the same stimulation and response but no decision making required, suggesting it does not merely reflect the maintenance of a motor plan. We conclude that beta band oscillations reflect the temporal and spatial dynamics of the accumulation and processing of evidence in the sensorimotor network leading to the decision outcome. PMID:21670296

  14. 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

  15. 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

  16. A vibrotactile behavioral battery for investigating somatosensory processing in children and adults.

    PubMed

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

    2013-08-15

    The cortical dynamics of somatosensory processing can be investigated using vibrotactile psychophysics. It has been suggested that different vibrotactile paradigms target different cortical mechanisms, and a number of recent studies have established links between somatosensory cortical function and measurable aspects of behavior. The relationship between cortical mechanisms and sensory function is particularly relevant with respect to developmental disorders in which altered inhibitory processing has been postulated, such as in ASD and ADHD. In this study, a vibrotactile battery consisting of nine tasks (incorporating reaction time, detection threshold, and amplitude- and frequency discrimination) was applied to a cohort of healthy adults and a cohort of typically developing children to assess the feasibility of such a vibrotactile battery in both cohorts, and the performance between children and adults was compared. These results showed that children and adults were both able to perform these tasks with a similar performance, although the children were slightly less sensitive in frequency discrimination. Performance within different task-groups clustered together in adults, providing further evidence that these tasks tap into different cortical mechanisms, which is also discussed. This clustering was not observed in children, which may be potentially indicative of development and a greater variability. In conclusion, in this study, we showed that both children and adults were able to perform an extensive vibrotactile battery, and we showed the feasibility of applying this battery to other (e.g., neurodevelopmental) cohorts to probe different cortical mechanisms.

  17. 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.

  18. The effects of acute cortical somatosensory deafferentation on grip force control

    PubMed Central

    Richardson, Andrew G.; Attiah, Mark A.; Berman, Jeffrey I.; Chen, H. Isaac; Liu, Xilin; Zhang, Milin; Van der Spiegel, Jan; Lucas, Timothy H.

    2015-01-01

    Grip force control involves mechanisms to adjust to unpredictable and predictable changes in loads during manual manipulation. Somatosensory feedback is critical not just to reactive, feedback control but also to updating the internal representations needed for proactive, feedforward control. The role of primary somatosensory cortex (S1) in these control strategies is not well established. Here we investigated grip force control in a rare case of acute central deafferentation following resection of S1. The subject had complete loss of somatosensation in the right arm without any deficit in muscle strength or reflexes. In the first task, the subject was asked to maintain a constant grip force with and without visual feedback. The subject was able to attain the target force with visual feedback but not maintain that force for more than a few seconds after visual feedback was removed. In the second task, the subject was asked to grip and move an instrumented object. The induced acceleration-dependent loads were countered by adjustments in grip force. Both amplitude and timing of the grip force modulation were not affected by deafferentation. The dissociation of these effects demonstrates the differential contribution of S1 to the mechanisms of grip force control. PMID:26587914

  19. Central somatosensory changes associated with improved dynamic balance in subjects with anterior cruciate ligament deficiency.

    PubMed

    Courtney, Carol A; Rine, Rose M

    2006-10-01

    To examine the mechanisms underlying return to pre-injury function in individuals with anterior cruciate ligament deficiency (ACL-D), we grouped 15 individuals (18-50 years of age) with ACL-D by functional status and strength (i.e. copers, non-copers and adapters) and compared measures of proprioception, somatosensory evoked potentials and neuromuscular responses to dynamic testing between groups. Seven subjects without ACL-D provided a comparative sample for dynamic balance testing (DBT). DBT consisted of bilateral EMG recordings of anterior tibialis, medial gastrocnemius, medial hamstrings and quadriceps during toes-down platform rotation. Relative latencies and relative amplitudes were calculated. Somatosensory evoked potential (SEPs) testing was based on identifying the presence or absence of the P27 potential. Proprioception was tested using threshold to detection of passive movement (TDPM). Those with the highest level of function, the copers, had a proprioceptive deficit, loss of P27 and altered postural synergies consisting of earlier and larger hamstring activation. Conversely, those with the lowest functional status, the non-copers, had strength and proprioception deficits, intact SEPs and inconsistent postural synergies. These results suggest that changes in central sensory representation may facilitate altered postural synergies that enable return to pre-injury functional status.

  20. [Methylmercury causes diffuse damage to the somatosensory cortex: how to diagnose Minamata disease].

    PubMed

    Ekino, Shigeo; Ninomiya, Tadashi; Imamura, Keiko; Susa, Mari

    2007-01-01

    The first acute case of methylmercury (MeHg) poisoning by the consumption of fish arose in Minamata, Japan, in 1953. It was officially recognized and called Minamata disease (MD) in 1956. There are still arguments about the definition of MD in terms of its associated clinical symptoms and lesions even 50 years after the initial recognition of MD. Studies on this MD epidemic are reviewed along with its historical background. Since MeHg dispersed from Minamata to the Shiranui Sea, residents living around the sea had been exposed to low-dose MeHg through fish consumption for about 20 years (at least from 1950 to 1968). These chronic MeHg poisoning patients complained of paresthesia at the distal parts of their extremities and around the lips even 30 years after the cessation of exposure to MeHg of anthropogenic origin. The persisting somatosensory disorders after the discontinuation of exposure to MeHg were induced by diffuse damage to the somatosensory cortex, but not by damage to the peripheral nervous system, as previously believed. Based on these findings, symptoms and lesions in MeHg poisoning are reappraised.

  1. Diagnostic use of dermatomal somatosensory-evoked potentials in spinal disorders: Case series

    PubMed Central

    Dikmen, Pinar Yalinay; Oge, A. Emre

    2013-01-01

    Objective/Context Dermatomal somatosensory-evoked potentials (dSEPs) may be valuable for diagnostic purposes in selected cases with spinal disorders. Design Reports on cases with successful use of dSEPs. Findings Cases 1 and 2 had lesions causing multiple root involvement (upper to middle lumbar region in Case 1 and lower sacral region in Case 2). Cystic lesions in both cases seemed to compress more than one nerve root, and stimulation at the center of the involved dermatomes in dSEPs helped to reveal the functional abnormality. Cases 3 and 4 had lesions involving the spinal cord with or without nerve root impairment. In Case 3, an magnetic resonance imaging (MRI)-verified lesion seemed to occupy a considerable volume of the lower spinal cord, causing only very restricted clinical sensory and motor signs. In Case 4, a cervical MRI showed a small well-circumscribed intramedullary lesion at right C2 level. All neurophysiological investigations were normal in the latter two patients (motor, tibial, and median somatosensory-evoked potentials in Case 3, and electromyography in both) except for the dSEPs. Conclusions Objectifying the presence and degree of sensory involvement in spinal disorders may be helpful for establishing diagnoses and in therapeutic decision-making. Valuable information could be provided by dSEPs in selected patients with multiple root or spinal cord involvement. PMID:24089995

  2. 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.

  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. Somatosensory organ topography across the star of the star-nosed mole (Condylura cristata)

    PubMed Central

    Sawyer, Eva K.; Catania, Kenneth C.

    2015-01-01

    Quantifying somatosensory receptor distribution in glabrous skin is usually difficult due to 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 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 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 in 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 to other sensory fovea. PMID:26659700

  5. 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.

  6. Abnormal activation of the primary somatosensory cortex in spasmodic dysphonia: an fMRI study.

    PubMed

    Simonyan, Kristina; Ludlow, Christy L

    2010-11-01

    Spasmodic dysphonia (SD) is a task-specific focal dystonia of unknown pathophysiology, characterized by involuntary spasms in the laryngeal muscles during speaking. Our aim was to identify symptom-specific functional brain activation abnormalities in adductor spasmodic dysphonia (ADSD) and abductor spasmodic dysphonia (ABSD). Both SD groups showed increased activation extent in the primary sensorimotor cortex, insula, and superior temporal gyrus during symptomatic and asymptomatic tasks and decreased activation extent in the basal ganglia, thalamus, and cerebellum during asymptomatic tasks. Increased activation intensity in SD patients was found only in the primary somatosensory cortex during symptomatic voice production, which showed a tendency for correlation with ADSD symptoms. Both SD groups had lower correlation of activation intensities between the primary motor and sensory cortices and additional correlations between the basal ganglia, thalamus, and cerebellum during symptomatic and asymptomatic tasks. Compared with ADSD patients, ABSD patients had larger activation extent in the primary sensorimotor cortex and ventral thalamus during symptomatic task and in the inferior temporal cortex and cerebellum during symptomatic and asymptomatic voice production. The primary somatosensory cortex shows consistent abnormalities in activation extent, intensity, correlation with other brain regions, and symptom severity in SD patients and, therefore, may be involved in the pathophysiology of SD.

  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. Somatosensory Rehabilitation for Neuropathic Pain in Burn Survivors: A Case Series.

    PubMed

    Nedelec, Bernadette; Calva, Valerie; Chouinard, Annick; Couture, Marie-Andrée; Godbout, Elisabeth; de Oliveira, Ana; LaSalle, Léo

    2016-01-01

    Neuropathic pain is an enormous rehabilitation challenge that has a substantial negative effect on patient function and quality of life. Somatosensory rehabilitation is a novel, nonpharmacological intervention described by Spicher based on the neuroplasticity of the somatosensory system. The rationale for somatosensory rehabilitation is that treating hypoesthesia will decrease neuropathic pain. Particularly for those with established neuropathic pain, the hypoesthesia may be masked by mechanical allodynia, which must be treated before treating the underlying hyposensitive zone. This case series describes the outcome of 17 burn survivors treated with somatosensory rehabilitation for their neuropathic pain. Before initiating treatment a modified version of the McGill Pain Questionnaire-short form (Questionnaire de la douleur St. Antoine, QDSA) was completed with the patients. The total score (×/64) was converted to percentage. The mechanical allodynia was assessed with the Rainbow Pain Scale that uses touch with the 15-g Semmes Weinstein Monofilaments (SWMs) and that was rated as painful on the visual analog scale (3/10 or resting pain + 1/10), as the criteria for mechanical allodynia. The severity level was assessed using seven predetermined SWMs to identify the smallest that elicited pain. The treatment consisted of avoiding all touch in the allodynic zone while concurrently providing proximal sensory and vibratory counter stimulation. Once the mechanical allodynia was eliminated, the underlying hypoesthesia was treated. Hypoesthesia was evaluated with the SWMs, and the percent improvement from baseline was calculated. The sensory reeducation treatment for hypoesthesia consisted of touch discrimination, texture perception, and vibratory stimulation. Seventeen patients (71/29% male/female, 21 ± 25% TBSA burned, 486 ± 596 days postburn) were evaluated and treated. Of these 15 initially presented with mechanical allodynia. The SWM scores had improved by 27 ± 21

  9. Influence of norepinephrine on somatosensory neuronal responses in the rat thalamus: a combined modeling and in vivo multi-channel, multi-neuron recording study.

    PubMed

    Moxon, Karen A; Devilbiss, David M; Chapin, John K; Waterhouse, Barry D

    2007-05-25

    Norepinephrine released within primary sensory circuits from locus coeruleus afferent fibers can produce a spectrum of modulatory actions on spontaneous or sensory-evoked activity of individual neurons. Within the ventral posterior medial thalamus, membrane currents modulated by norepinephrine have been identified. However, the relationship between the cellular effects of norepinephrine and the impact of norepinephrine release on populations of neurons encoding sensory signals is still open to question. To address this lacuna in understanding the net impact of the noradrenergic system on sensory signal processing, a computational model of the rat trigeminal somatosensory thalamus was generated. The effects of independent manipulation of different cellular actions of norepinephrine on simulated afferent input to the computational model were then examined. The results of these simulations aided in the design of in vivo neural ensemble recording experiments where sensory-driven responses of thalamic neurons were measured before and during locus coeruleus activation in waking animals. Together the simulated and experimental results reveal several key insights regarding the regulation of neural network operation by norepinephrine including: 1) cell-specific modulatory actions of norepinephrine, 2) mechanisms of norepinephrine action that can improve the tuning of the network and increase the signal-to-noise ratio of cellular responses in order to enhance network representation of salient stimulus features and 3) identification of the dynamic range of thalamic neuron function through which norepinephrine operates.

  10. Receptive field scatter, topography and map variability in different layers of the hindpaw representation of rat somatosensory cortex.

    PubMed

    Haupt, S Shuichi; Spengler, Friederike; Husemann, Robert; Dinse, Hubert R

    2004-04-01

    We recorded neurons extracellularly in layers II/III, IV, and V of the hindpaw representation of primary somatosensory cortex in anesthetized rats and studied laminar features of receptive fields (RFs) and representational maps. On average, RFs were smallest in layer IV and largest in layer V; however, for individual penetrations we found substantial deviations from this rule. Within the hindpaw representation, a distinct rostrocaudal gradient of RF size was present in all layers. While layer V RFs were generally largest independent of this gradient, layer IV RFs recorded caudally representing the proximal portions of the paw were larger than layer II/III RFs recorded rostrally representing the digits. The individual scatter of the locations of RFs across laminar groups was in the range of several millimeters, corresponding to about 25% of the average RF diameter. The cutaneous representations of the hindpaw in extragranular layers were confined to the areal extent defined by responsive sites in layer IV. Comparison between RFs determined quantitatively and by handplotting showed a reliable correspondence. Repeated measurements of RFs revealed spontaneous fluctuations of RF size of no more than 5% of the initial condition over an observation period of several hours. The topography and variability of cortical maps of the hindpaw representation were studied with a quantitative interpolation method taking into account the geometric centers of RFs and the corresponding cortical recording sites. On average, the overall topography in terms of preservation of neighborhood relations was present in all layers, although some individual maps showed severe distortions of topography. Factors contributing to map variability were overall position of the representation on the cortical surface, internal topography and spatial extent. Interindividual variability of map layout was always highest in the digit representations. Local topographic orderliness was lowest in layer V, but

  11. Test-retest reliability of quantitative sensory testing for mechanical somatosensory and pain modulation assessment of masticatory structures.

    PubMed

    Costa, Y M; Morita-Neto, O; de Araújo-Júnior, E N S; Sampaio, F A; Conti, P C R; Bonjardim, L R

    2017-03-01

    Assessing the reliability of medical measurements is a crucial step towards the elaboration of an applicable clinical instrument. There are few studies that evaluate the reliability of somatosensory assessment and pain modulation of masticatory structures. This study estimated the test-retest reliability, that is over time, of the mechanical somatosensory assessment of anterior temporalis, masseter and temporomandibular joint (TMJ) and the conditioned pain modulation (CPM) using the anterior temporalis as the test site. Twenty healthy women were evaluated in two sessions (1 week apart) by the same examiner. Mechanical detection threshold (MDT), mechanical pain threshold (MPT), wind-up ratio (WUR) and pressure pain threshold (PPT) were assessed on the skin overlying the anterior temporalis, masseter and TMJ of the dominant side. CPM was tested by comparing PPT before and during the hand immersion in a hot water bath. anova and intra-class correlation coefficients (ICCs) were applied to the data (α = 5%). The overall ICCs showed acceptable values for the test-retest reliability of mechanical somatosensory assessment of masticatory structures. The ICC values of 75% of all quantitative sensory measurements were considered fair to excellent (fair = 8·4%, good = 33·3% and excellent = 33·3%). However, the CPM paradigm presented poor reliability (ICC = 0·25). The mechanical somatosensory assessment of the masticatory structures, but not the proposed CPM protocol, can be considered sufficiently reliable over time to evaluate the trigeminal sensory function.

  12. Long-term dynamics of somatosensory activity in a stroke model of distal middle cerebral artery oclussion

    PubMed Central

    Barios, Juan A; Pisarchyk, Liudmila; Fernandez-Garcia, Laura; Barrio, Luis C; Ramos, Milagros; Martinez-Murillo, Ricardo

    2015-01-01

    A constant challenge in experimental stroke is the use of appropriate tests to identify signs of recovery and adverse effects linked to a particular therapy. In this study, we used a long-term longitudinal approach to examine the functional brain changes associated with cortical infarction in a mouse model induced by permanent ligation of the middle cerebral artery (MCA). Sensorimotor function and somatosensory cortical activity were evaluated with fault-foot and forelimb asymmetry tests in combination with somatosensory evoked potentials. The stroke mice exhibited both long-term deficits in the functional tests and impaired responses in the infarcted and intact hemispheres after contralateral and ipsilateral forepaw stimulation. In the infarcted hemisphere, reductions in the amplitudes of evoked responses were detected after contralateral and ipsilateral stimulation. In the intact hemisphere, and similar to cortical stroke patients, a gradual hyperexcitability was observed after contralateral stimulation but no parallel evidence of a response was detected after ipsilateral stimulation. Our results suggest the existence of profound and persistent changes in the somatosensory cortex in this specific mouse cortical stroke model. The study of evoked potentials constitutes a feasible and excellent tool for evaluating the fitness of the somatosensory cortex in relation to functional recovery after preclinical therapeutic intervention. PMID:26661150

  13. 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.

  14. Chronic exposure of adult rats to low doses of methylmercury induced a state of metabolic deficit in the somatosensory cortex.

    PubMed

    Kong, Hang-Kin; Wong, Ming-Hung; Chan, Hing-Man; Lo, Samuel Chun-Lap

    2013-11-01

    Because of the ever-increasing bioaccumulation of methylmercury (MeHg) in the marine food chain, human consumers are exposed to low doses of MeHg continually through seafood consumption. Epidemiological studies strongly suggest that chronic prenatal exposure to nanomolar of MeHg has immense negative impacts on neurological development in neonates. However, effects of chronic exposure to low doses (CELDs) of MeHg in adult brains on a molecular level are unknown. The current study aims to investigate the molecular effects of CELD of MeHg on adult somatosensory cortex in a rat model using proteomic techniques. Young adult rats were fed with a low dose of MeHg (40 μg/kg body weight/day) for a maximum of 12 weeks. Whole proteome expression of the somatosensory cortex (S1 area) of normal rats and those with CELD to MeHg were compared. Levels of MeHg, total calcium, adenosine triphosphate (ATP), and pyruvate were also measured. Comparative proteomic studies of the somatosensory cortexes revealed that 94 proteins involved in the various metabolic processes (including carbohydrate metabolism, generation of precursors for essential metabolites, energy, proteins, cellular components for morphogenesis, and neurotransmission) were down-regulated. Consequently, levels of important end products of active metabolism including ATP, pyruvate, and total calcium were also found to be significantly reduced concomitantly. Our results showed that CELD of MeHg induced a state of metabolic deficit in the somatosensory cortex of adult rats.

  15. [Cyclic processes in neuronal populations of the cat somatosensory cortex during extero- and interoceptive activation and in extinction].

    PubMed

    Lavrov, V V

    1991-11-01

    Comparative analysis of the EEG activation responses and multiunit responses in the cortical somatosensory (I) areas revealed a cyclic character of the multiunit discharges in response to light, sound, mechanical and chemical stimuli in alert cats. The fluctuations were reducing to initial values in the course of the stimulation.

  16. 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…

  17. 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

  18. 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

  19. 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

  20. Dual-Arm Generalized Compliant Motion With Shared Control

    NASA Technical Reports Server (NTRS)

    Backes, Paul G.

    1994-01-01

    Dual-Arm Generalized Compliant Motion (DAGCM) primitive computer program implementing improved unified control scheme for two manipulator arms cooperating in task in which both grasp same object. Provides capabilities for autonomous, teleoperation, and shared control of two robot arms. Unifies cooperative dual-arm control with multi-sensor-based task control and makes complete task-control capability available to higher-level task-planning computer system via large set of input parameters used to describe desired force and position trajectories followed by manipulator arms. Some concepts discussed in "A Generalized-Compliant-Motion Primitive" (NPO-18134).

  1. Dual-Mode Combustor

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  2. Dual approximations in optimal control

    NASA Technical Reports Server (NTRS)

    Hager, W. W.; Ianculescu, G. D.

    1984-01-01

    A dual approximation for the solution to an optimal control problem is analyzed. The differential equation is handled with a Lagrange multiplier while other constraints are treated explicitly. An algorithm for solving the dual problem is presented.

  3. Canopy Research Network seeks input

    NASA Astrophysics Data System (ADS)

    In July 1993, the Canopy Research Network was established with a 2-year planning grant from the National Science Foundation to bring together forest canopy researchers, quantitative scientists, and computer specialists to establish methods for collecting, storing, analyzing, interpreting, and displaying three-dimensional data that relate to tree crowns and forest canopies. The CRN is now soliciting input from scientists in other fields who may have developed techniques and software to help obtain answers to questions that concern the complex three-dimensional structure of tree crowns and forest canopies. Over the next 3 years, the CRN plans to compile an array of research questions and issues requiring information on canopy structure, examine useful information models and software tools already in use in allied fields, and develop conceptual models and recommendations for the types and format of information and analyses necessary to answer research questions posed by canopy researchers.

  4. Effects of peripherally and centrally acting analgesics on somato-sensory evoked potentials.

    PubMed Central

    Moore, U J; Marsh, V R; Ashton, C H; Seymour, R A

    1995-01-01

    1. The effects of aspirin 1000 mg, paracetamol 1000 mg, codeine 60 mg on somatosensory evoked potentials (SEPs) were measured in a four-way cross-over study. 2. SEPs were elicited by electrical stimulation of the skin overlying the digital nerve at intensities close to pain threshold. 3. Amplitudes and latencies of both early and late SEPs were recorded, as well as first sensory threshold and subjective pain threshold. 4. None of the study medications affected the amplitude or latency of the late SEP components (100-250 ms post-stimulus). The amplitude of early components (15-30 ms post-stimulus) was also unaffected, but aspirin shortened the latency 30 min after ingestion. 5. Sensory detection and pain threshold to electrical skin stimulation were also unaffected by any of the study medications despite subjective central effects with codeine. PMID:8562292

  5. Subliminal stimuli modulate somatosensory perception rhythmically and provide evidence for discrete perception

    PubMed Central

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

    2017-01-01

    Despite being experienced as continuous, there is an ongoing debate if perception is an intrinsically discrete process, with incoming sensory information treated as a succession of single perceptual cycles. Here, we provide causal evidence that somatosensory perception is composed of discrete perceptual cycles. We used in humans an electrotactile temporal discrimination task preceded by a subliminal (i.e., below perceptual threshold) stimulus. Although not consciously perceived, subliminal stimuli are known to elicit neuronal activity in early sensory areas and modulate the phase of ongoing neuronal oscillations. We hypothesized that the subliminal stimulus indirectly, but systematically modulates the ongoing oscillatory phase in S1, thereby rhythmically shaping perception. The present results confirm that, without being consciously perceived, the subliminal stimulus critically influenced perception in the discrimination task. Importantly, perception was modulated rhythmically, in cycles corresponding to the beta-band (13–18 Hz). This can be compellingly explained by a model of discrete perceptual cycles. PMID:28276493

  6. The origin, and application of somatosensory evoked potentials as a neurophysiological technique to investigate neuroplasticity.

    PubMed

    Passmore, Steven R; Murphy, Bernadette; Lee, Timothy D

    2014-06-01

    Somatosensory evoked potentionals (SEPs) can be used to elucidate differences in cortical activity associated with a spinal manipulation (SM) intervention. The purpose of this narrative review is to overview the origin and application of SEPs, a neurophysiological technique to investigate neuroplasticity. Summaries of: 1) parameters for SEP generation and waveform recording; 2) SEP peak nomenclature, interpretation and generators; 3) peaks pertaining to tactile information processing (relevant to both chiropractic and other manual therapies); 4) utilization and application of SEPs; 5) SEPs concurrent with an experimental task and at baseline/control/pretest; 6) SEPs pain studies; and 7) SEPs design (pre/post) and neural reorganization/neuroplasticity; and 8) SEPs and future chiropractic research are all reviewed. Understanding what SEPs are, and their application allows chiropractors, educators, and other manual therapists interested in SM to understand the context, and importance of research findings from SM studies that involve SEPs.

  7. Long-latency components of somatosensory evoked potentials during passive tactile perception of gratings.

    PubMed

    Genna, C; Artoni, F; Fanciullacci, C; Chisari, C; Oddo, C M; Micera, S

    2016-08-01

    Perception of tactile stimuli elicits Somatosensory Evoked Potentials (SEPs) that can be recorded via non-invasive electroencephalography (EEG). However, it is not yet clear how SEPs localization, shape and latency are modulated by different stimuli during mechanical tactile stimulation of fingertips. The aim of this work is thus to characterize SEPs generated by the tactile perception of gratings during dynamic passive stimulation of the dominant fingertip by means of a mechatronic platform. Results show that a random sequence of stimuli elicited SEPs with two long-latency components: (i) a negative deflection around 140 ms located in the frontal-central-parietal side in the contralateral hemisphere; (ii) a positive deflection around 250 ms located in the frontal-central midline. Time-frequency analysis revealed significant continuous bilateral desynchronization in the alpha band throughout the passive stimulation. These results are a fundamental step towards building a model of brain responses during perception of tactile stimuli for future benchmarking studies.

  8. Regional hypoplasia of somatosensory cortex in growth-retarded mice (grt/grt).

    PubMed

    Sawada, Kazuhiko; Saito, Shigeyoshi; Sugasawa, Akari; Sato, Chika; Aoyama, Junya; Ohara, Naoko; Horiuchi-Hirose, Miwa; Kobayashi, Tetsuya

    2016-07-01

    Growth-retarded mouse (grt/grt) is a spontaneous mutant that is known as an animal model for primary congenital hypothyroidism caused by resistance to TSH signaling. The regional pattern of cerebral cortical hypoplasia was characterized in grt/grt mice. Ex vivo computed tomography (CT)-based volumetry was examined in four regions of the cerebral cortex, i.e., prefrontal, frontal, parietal and occipito-temporal regions, which were demarcated by structural landmarks on coronal CT images. A region-specific reduced volume of the parietal cortical region covering most of the somatosensory cortex was noted in grt/grt mice rather than in both heterozygous (grt/+) and wild-type (+/+) mice. We concluded that the cortical hypoplasia in grt/grt was seen in identical cortical regions corresponding to human congenital hypothyroidism.

  9. Unit responses of the secondary somatosensory cortex during defensive conditioning in cats.

    PubMed

    Kruchenko, Z A; Taran, G A

    1980-01-01

    Unit responses in the secondary somatosensory cortex during the formation and extinction of a defensive conditioned reflex to acoustic stimulation were investigated in chronic experiments on cats. In 21 of 28 neurons tested during defensive conditioning the firing pattern changed in accordance with the character of responses to electric shock reinforcement. Two types of conditioned-reflex unit responses were distinguished: excitatory and inhibitory. Most neurons responding to the conditioned stimulus by activation did so during the first 50 msec, which was 80-100 msec before the conditioned motor response. Considerable variability of the unit responses was observed during conditioning. By the time of stabilization of the conditioned-reflex connections the unit response to the conditioned stimulus was stable in form. The pattern of extinction of the conditioned unit activity was expressed as a decrease in the discharge frequency in responses of excitatory type and disinhibition of activity in the case of inhibitory responses.

  10. 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.

  11. Whisker Deprivation Drives Two Phases of Inhibitory Synapse Weakening in Layer 4 of Rat Somatosensory Cortex.

    PubMed

    Gainey, Melanie A; Wolfe, Renna; Pourzia, Olivia; Feldman, Daniel E

    2016-01-01

    Inhibitory synapse development in sensory neocortex is experience-dependent, with sustained sensory deprivation yielding fewer and weaker inhibitory synapses. Whether this represents arrest of synapse maturation, or a more complex set of processes, is unclear. To test this, we measured the dynamics of inhibitory synapse development in layer 4 of rat somatosensory cortex (S1) during continuous whisker deprivation from postnatal day 7, and in age-matched controls. In deprived columns, spontaneous miniature inhibitory postsynaptic currents (mIPSCs) and evoked IPSCs developed normally until P15, when IPSC amplitude transiently decreased, recovering by P16 despite ongoing deprivation. IPSCs remained normal until P22, when a second, sustained phase of weakening began. Delaying deprivation onset by 5 days prevented the P15 weakening. Both early and late phase weakening involved measurable reduction in IPSC amplitude relative to prior time points. Thus, deprivation appears to drive two distinct phases of active IPSC weakening, rather than simple arrest of synapse maturation.

  12. Effects of mindfulness meditation training on anticipatory alpha modulation in primary somatosensory cortex.

    PubMed

    Kerr, Catherine E; Jones, Stephanie R; Wan, Qian; Pritchett, Dominique L; Wasserman, Rachel H; Wexler, Anna; Villanueva, Joel J; Shaw, Jessica R; Lazar, Sara W; Kaptchuk, Ted J; Littenberg, Ronnie; Hämäläinen, Matti S; Moore, Christopher I

    2011-05-30

    During selective attention, ∼7-14 Hz alpha rhythms are modulated in early sensory cortices, suggesting a mechanistic role for these dynamics in perception. Here, we investigated whether alpha modulation can be enhanced by "mindfulness" meditation (MM), a program training practitioners in sustained attention to body and breath-related sensations. We hypothesized that participants in the MM group would exhibit enhanced alpha power modulation in a localized representation in the primary somatosensory neocortex in response to a cue, as compared to participants in the control group. Healthy subjects were randomized to 8-weeks of MM training or a control group. Using magnetoencephalographic (MEG) recording of the SI finger representation, we found meditators demonstrated enhanced alpha power modulation in response to a cue. This finding is the first to show enhanced local alpha modulation following sustained attentional training, and implicates this form of enhanced dynamic neural regulation in the behavioral effects of meditative practice.

  13. Organization of somatosensory cortex in the northern grasshopper mouse (Onychomys leucogaster), a predatory rodent

    PubMed Central

    Sarko, Diana K.; Leitch, Duncan B.; Girard, Isabelle; Sikes, Robert S.; Catania, Kenneth C.

    2010-01-01

    Northern grasshopper mice (Onychomys leucogaster) are among the most highly carnivorous rodents in North America. Because predatory mammals may have specialization of senses used to detect prey, we investigated the organization of sensory areas within grasshopper mouse neocortex and quantified the number of myelinated axons in grasshopper mouse trigeminal, cochlear, and optic nerves. Multiunit electrophysiological recordings combined with analysis of flattened sections of neocortex processed for cytochrome oxidase were used to determine the topography of primary somatosensory cortex (S1) and the location and size of both the visual and auditory cortex in adult animals. These findings were then related to the distinctive chemoarchitecture of layer IV visible in flattened cortical sections of juvenile grasshopper mice labeled with the serotonin transporter (SERT) antibody, revealing a striking correspondence between electrophysiological maps and cortical anatomy. PMID:21120928

  14. 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

  15. Effect of raising body temperature on visual and somatosensory evoked potentials in patients with multiple sclerosis.

    PubMed Central

    Matthews, W B; Read, D J; Pountney, E

    1979-01-01

    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. PMID:438834

  16. Predictability of Painful Stimulation Modulates the Somatosensory-Evoked Potential in the Rat

    PubMed Central

    Schaap, Manon W. H.; van Oostrom, Hugo; Doornenbal, Arie; Baars, Annemarie M.; Arndt, Saskia S.; Hellebrekers, Ludo J.

    2013-01-01

    Somatosensory-evoked potentials (SEPs) are used in humans and animals to increase knowledge about nociception and pain. Since the SEP in humans increases when noxious stimuli are administered unpredictably, predictability potentially influences the SEP in animals as well. To assess the effect of predictability on the SEP in animals, classical fear conditioning was applied to compare SEPs between rats receiving SEP-evoking electrical stimuli either predictably or unpredictably. As in humans, the rat’s SEP increased when SEP-evoking stimuli were administered unpredictably. These data support the hypothesis that the predictability of noxious stimuli plays a distinctive role in the processing of these stimuli in animals. The influence of predictability should be considered when studying nociception and pain in animals. Additionally, this finding suggests that animals confronted with (un)predictable noxious stimuli can be used to investigate the mechanisms underlying the influence of predictability on central processing of noxious stimuli. PMID:23613862

  17. 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

  18. Exploring the variability of single trials in somatosensory evoked responses using constrained source extraction and RMT.

    PubMed

    Koutras, A; Kostopoulos, G K; Ioannides, A A

    2008-03-01

    This paper describes the theoretical background of a new data-driven approach to encephalographic single-trial (ST) data analysis. Temporal constrained source extraction using sparse decomposition identifies signal topographies that closely match the shape characteristics of a reference signal, one response for each ST. The correlations between these ST topographies are computed for formal Correlation Matrix Analysis (CMA) based on Random Matrix Theory (RMT). The RMT-CMA provides clusters of similar ST topologies in a completely unsupervised manner. These patterns are then classified into deterministic set and noise using well established RMT results. The efficacy of the method is applied to EEG and MEG data of somatosensory evoked responses (SERs). The results demonstrate that the method can recover brain signals with time course resembling the reference signal and follow changes in strength and/or topography in time by simply stepping the reference signal through time.

  19. 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.

  20. The origin, and application of somatosensory evoked potentials as a neurophysiological technique to investigate neuroplasticity

    PubMed Central

    Passmore, Steven R.; Murphy, Bernadette; Lee, Timothy D.

    2014-01-01

    Somatosensory evoked potentionals (SEPs) can be used to elucidate differences in cortical activity associated with a spinal manipulation (SM) intervention. The purpose of this narrative review is to overview the origin and application of SEPs, a neurophysiological technique to investigate neuroplasticity. Summaries of: 1) parameters for SEP generation and waveform recording; 2) SEP peak nomenclature, interpretation and generators; 3) peaks pertaining to tactile information processing (relevant to both chiropractic and other manual therapies); 4) utilization and application of SEPs; 5) SEPs concurrent with an experimental task and at baseline/control/pretest; 6) SEPs pain studies; and 7) SEPs design (pre/post) and neural reorganization/neuroplasticity; and 8) SEPs and future chiropractic research are all reviewed. Understanding what SEPs are, and their application allows chiropractors, educators, and other manual therapists interested in SM to understand the context, and importance of research findings from SM studies that involve SEPs. PMID:24932021

  1. 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.

  2. Rat whisker motor cortex is subdivided into sensory-input and motor-output areas

    PubMed Central

    Smith, Jared B.; Alloway, Kevin D.

    2013-01-01

    Rodent whisking is an exploratory behavior that can be modified by sensory feedback. Consistent with this, many whisker-sensitive cortical regions project to agranular motor [motor cortex (MI)] cortex, but the relative topography of these afferent projections has not been established. Intracortical microstimulation (ICMS) evokes whisker movements that are used to map the functional organization of MI, but no study has compared the whisker-related inputs to MI with the ICMS sites that evoke whisker movements. To elucidate this relationship, anterograde tracers were placed in posterior parietal cortex (PPC) and in the primary somatosensory (SI) and secondary somatosensory (SII) cortical areas so that their labeled projections to MI could be analyzed with respect to ICMS sites that evoke whisker movements. Projections from SI and SII terminate in a narrow zone that marks the transition between the medial agranular (AGm) and lateral agranular (AGl) cortical areas, but PPC projects more medially and terminates in AGm proper. Paired recordings of MI neurons indicate that the region between AGm and AGl is highly responsive to whisker deflections, but neurons in AGm display negligible responses to whisker stimulation. By contrast, AGm microstimulation is more effective in evoking whisker movements than microstimulation of the transitional region between AGm and AGl. The AGm region was also found to contain a larger concentration of corticotectal neurons, which could convey whisker-related information to the facial nucleus. These results indicate that rat whisker MI is comprised of at least two functionally distinct subregions: a sensory processing zone in the transitional region between AGm and AGl, and a motor-output region located more medially in AGm proper. PMID:23372545

  3. 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 experime