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Sample records for active motor threshold

  1. Single-unit activity, threshold crossings, and local field potentials in motor cortex differentially encode reach kinematics.

    PubMed

    Perel, Sagi; Sadtler, Patrick T; Oby, Emily R; Ryu, Stephen I; Tyler-Kabara, Elizabeth C; Batista, Aaron P; Chase, Steven M

    2015-09-01

    A diversity of signals can be recorded with extracellular electrodes. It remains unclear whether different signal types convey similar or different information and whether they capture the same or different underlying neural phenomena. Some researchers focus on spiking activity, while others examine local field potentials, and still others posit that these are fundamentally the same signals. We examined the similarities and differences in the information contained in four signal types recorded simultaneously from multielectrode arrays implanted in primary motor cortex: well-isolated action potentials from putative single units, multiunit threshold crossings, and local field potentials (LFPs) at two distinct frequency bands. We quantified the tuning of these signal types to kinematic parameters of reaching movements. We found 1) threshold crossing activity is not a proxy for single-unit activity; 2) when examined on individual electrodes, threshold crossing activity more closely resembles LFP activity at frequencies between 100 and 300 Hz than it does single-unit activity; 3) when examined across multiple electrodes, threshold crossing activity and LFP integrate neural activity at different spatial scales; and 4) LFP power in the "beta band" (between 10 and 40 Hz) is a reliable indicator of movement onset but does not encode kinematic features on an instant-by-instant basis. These results show that the diverse signals recorded from extracellular electrodes provide somewhat distinct and complementary information. It may be that these signal types arise from biological phenomena that are partially distinct. These results also have practical implications for harnessing richer signals to improve brain-machine interface control. PMID:26133797

  2. Ceruletide increases dose dependently both jejunal motor activity and threshold and tolerance to experimentally induced pain in healthy man.

    PubMed Central

    Stacher, G; Steinringer, H; Schmierer, G; Schneider, C; Winklehner, S; Mittelbach, G; De Paolis, C; Praga, C

    1984-01-01

    The effects of ceruletide on jejunal motility and experimentally induced pain were studied in 16 healthy men, who participated each in four experiments and received in random double blind fashion 5, 10, or 20 micrograms ceruletide intramuscularly or placebo. Jejunal pressures were recorded by three perfused catheters with orifices between 10 and 20 cm aboral of the ligament of Treitz. Ceruletide dose dependently diminished phase I and increased phase II type activity and tended to reduce the number, but not the duration, of activity fronts. The number and amplitude of contractions as well as the area under the curve increased significantly and dose dependently as did threshold and tolerance to electrically and threshold to thermally induced pain. Only mild sedative and other side effects occurred. PMID:6714795

  3. Increased transcranial magnetic motor threshold after ECT. A case report.

    PubMed

    Sommer, Martin; Dieterich, Anja; Rüther, Eckart; Paulus, Walter; Wiltfang, Jens

    2002-10-01

    Electroconvulsive therapy (ECT) is a powerful antidepressive treatment, but its mechanism of action remains poorly understood. To clarify the influence of ECT on corticospinal tract excitability we tested the motor threshold, the motor evoked potential (MEP) input/output curve, and the intracortical excitability using transcranial magnetic stimulation in a depressed patient before and after successful treatment with ECT. Resting motor thresholds were increased bilaterally after treatment, and the input/output curve less steep. These results point to a decreased excitability of the corticospinal motor tract after successful ECT. PMID:12451468

  4. Transposed firing activation of motor units

    PubMed Central

    Kline, Joshua C.; Contessa, Paola

    2014-01-01

    Muscles are composed of groups of muscle fibers, called motor units, each innervated by a single motoneuron originating in the spinal cord. During constant or linearly varying voluntary force contractions, motor units are activated in a hierarchical order, with the earlier-recruited motor units having greater firing rates than the later-recruited ones. We found that this normal pattern of firing activation can be altered during oscillatory contractions where the force oscillates at frequencies ≥2 Hz. During these high-frequency oscillations, the activation of the lower-threshold motor units effectively decreases and that of the higher-threshold motor units effectively increases. This transposition of firing activation provides means to activate higher-threshold motor units preferentially. Our results demonstrate that the hierarchical regulation of motor unit activation can be manipulated to activate specific motoneuron populations preferentially. This finding can be exploited to develop new forms of physical therapies and exercise programs that enhance muscle performance or that target the preferential atrophy of high-threshold motor units as a result of aging or motor disorders such as stroke and amyotrophic lateral sclerosis. PMID:24899671

  5. Erosive burning threshold conditions in solid rocket motors

    NASA Technical Reports Server (NTRS)

    Strand, L. D.; Cohen, N. S.

    1989-01-01

    Erosive burning has been predicted to be enhanced by factors that increase the level of turbulence close to the propellant surface, such a high cross flow velocity, low surface blowing rate, propellant surface roughness, and adverse pressure gradient. A study is reported which was carried out with the objective of measuring the effects of these parameters on the scaling to larger rocket motor sizes of the transition to, or threshold conditions for, erosive burning rate augmentation. The results are used to develop a scaling criterion for the threshold conditions for erosive burning.

  6. Repeat exposure to ciguatoxin leads to enhanced and sustained thermoregulatory, pain threshold and motor activity responses in mice: relationship to blood ciguatoxin concentrations.

    PubMed

    Bottein Dechraoui, Marie-Yasmine; Rezvani, Amir H; Gordon, Christopher J; Levin, Edward D; Ramsdell, John S

    2008-04-01

    Ciguatera is a common illness in tropical and subtropical regions that manifests in complex and long-lived symptoms which are more severe in subsequent exposures. This study measures central and peripheral neurologic signs, in parallel with blood toxin levels, in mice exposed once or twice (at 3 days interval) to a sublethal dose of ciguatoxin P-CTX-1 (0.26ng/g via i.p.). Mice were implanted with radiotransmitters to monitor motor activity and core temperature. A single exposure to ciguatoxin elicited an immediate and transient decrease in motor activity and temperature, and subsequent long-lasting thermoregulatory dysfunction resulting in stabilized body temperature around 36.0 degrees C with no observable circadian rhythm. The hypothermic response and the reduced activity were enhanced with a second exposure with 30% of the mice dying within 7h. Measurement of the peripheral nervous system by the tail flick assay revealed increased latency with a single ciguatoxin exposure, and a greater effect following the second exposure. Toxin was measurable in blood up to 3 days following the first exposure; at the 1h time point the concentrations were significantly elevated after a second exposure. These findings indicate an early response to ciguatoxin manifest in a central response to lower body temperature and reduce motor activity and a more persistent effect on the peripheral system leading to spinal heat antinociception and delayed fever-like response. The greater neurological response to a second ciguatoxin exposure was associated with elevated concentrations of ciguatoxin in the blood solely over the first hour of exposure. In conclusion, a single exposure to toxin exerts a significant neurological response which may be enhanced with subsequent exposure. PMID:18280027

  7. Effect of electrode cap on measured cortical motor threshold.

    PubMed

    Julkunen, Petro; Säisänen, Laura; Sarasti, Maria; Könönen, Mervi

    2009-01-30

    We investigated the role of electrode cap use in the determination of the cortical motor threshold (MT), and the resulting changes in the recorded motor evoked potentials (MEPs). We also tested whether the induced changes in determined MT could be corrected via previously introduced correction method. Sixteen healthy subjects were studied. Navigated TMS was used for mapping the optimal representation area of the thenar musculature in the primary motor cortex and individual MTs were determined with and without the use of the electrode cap. A mathematical correction was utilized to compensate for the effect of electrode cap in the MTs. Individual MEPs were also measured. We observed a significant (p<0.05) increase in the determined MTs attributable to the use of the electrode cap. At the group level this difference was reduced significantly (p<0.01) by the use of the correction method. However, at the individual level the efficiency of the correction was poor. The MEP-amplitudes were not affected whether measured with or without the electrode cap. The electrode cap affects significantly the cortical MT measured as stimulation intensity making the comparison of MTs difficult with other studies not having used an electrode cap. PMID:18801386

  8. The role of stretch reflex threshold regulation in normal and impaired motor control.

    PubMed

    Levin, M F; Feldman, A G

    1994-09-19

    Some hypotheses suggest that stretch reflex threshold regulation may be an essential element of motor control. Disturbances in this mechanism may lead to motor dysfunction. We investigated this possibility by comparing stretch reflex threshold regulation in 11 spastic hemiparetic and 6 normal subjects. Subjects sat with their arms fully supported in a forearm and hand mold attached to a manipulandum mounted on and controlled by a torque motor. They remained completely passive while their elbow was extended from 30 degrees flexion through an arc of 100 degrees. Displacement and velocity of the forearm were measured as well as EMG signals from 2 elbow flexors and 2 elbow extensors, when the elbow flexors were stretched at each of 7 velocities. Velocities ranged from 8 to 160 degrees/s for hemiparetic subjects and from 32 to 300 degrees/s for normal subjects. Phase diagrams (velocity versus angle) were plotted and the threshold angles (lambda) for muscle activation at each velocity of stretch were used to determine the static stretch reflex threshold (lambda) and the slope (mu) of the relationship between the lambda s and velocity. Our main findings were that static and dynamic stretch reflex thresholds were decreased in spastic hemiparetic compared to normal subjects and that the thresholds depended on velocity. The static threshold value correlated with the severity of clinically measured spasticity. In addition, the range of regulation of lambda was decreased in the patients compared to normal. This may explain some of the problems of force and position regulation as well as hypertonus (and weakness) common to these patients. PMID:7820623

  9. [Nonlinear magnetohydrodynamics]. [Threshold unstable MHD activity

    SciTech Connect

    Not Available

    1992-01-01

    Theoretical predictions were compared with available data from JET on the threshold unstable MHD activity in toroidal confinement devices. In particular, questions arising as to Hartmans number and the selection of a kinematic viscosity are discussed.

  10. Effects of stimulation parameters and electrode location on thresholds for epidural stimulation of cat motor cortex

    NASA Astrophysics Data System (ADS)

    Wongsarnpigoon, Amorn; Grill, Warren M.

    2011-12-01

    Epidural electrical stimulation (ECS) of the motor cortex is a developing therapy for neurological disorders. Both placement and programming of ECS systems may affect the therapeutic outcome, but the treatment parameters that will maximize therapeutic outcomes and minimize side effects are not known. We delivered ECS to the motor cortex of anesthetized cats and investigated the effects of electrode placement and stimulation parameters on thresholds for evoking motor responses in the contralateral forelimb. Thresholds were inversely related to stimulation frequency and the number of pulses per stimulus train. Thresholds were lower over the forelimb representation in motor cortex (primary site) than surrounding sites (secondary sites), and thresholds at sites <4 mm away from the primary site were significantly lower than at sites >4 mm away. Electrode location and montage influenced the effects of polarity on thresholds: monopolar anodic and cathodic thresholds were not significantly different over the primary site, cathodic thresholds were significantly lower than anodic thresholds over secondary sites and bipolar thresholds were significantly lower with the anode over the primary site than with the cathode over the primary site. A majority of bipolar thresholds were either between or equal to the respective monopolar thresholds, but several bipolar thresholds were greater than or less than the monopolar thresholds of both the anode and cathode. During bipolar stimulation, thresholds were influenced by both electric field superposition and indirect, synaptically mediated interactions. These results demonstrate the influence of stimulation parameters and electrode location during cortical stimulation, and these effects should be considered during the programming of systems for therapeutic cortical stimulation.

  11. Motor Activity Improves Temporal Expectancy

    PubMed Central

    Fautrelle, Lilian; Mareschal, Denis; French, Robert; Addyman, Caspar; Thomas, Elizabeth

    2015-01-01

    Certain brain areas involved in interval timing are also important in motor activity. This raises the possibility that motor activity might influence interval timing. To test this hypothesis, we assessed interval timing in healthy adults following different types of training. The pre- and post-training tasks consisted of a button press in response to the presentation of a rhythmic visual stimulus. Alterations in temporal expectancy were evaluated by measuring response times. Training consisted of responding to the visual presentation of regularly appearing stimuli by either: (1) pointing with a whole-body movement, (2) pointing only with the arm, (3) imagining pointing with a whole-body movement, (4) simply watching the stimulus presentation, (5) pointing with a whole-body movement in response to a target that appeared at irregular intervals (6) reading a newspaper. Participants performing a motor activity in response to the regular target showed significant improvements in judgment times compared to individuals with no associated motor activity. Individuals who only imagined pointing with a whole-body movement also showed significant improvements. No improvements were observed in the group that trained with a motor response to an irregular stimulus, hence eliminating the explanation that the improved temporal expectations of the other motor training groups was purely due to an improved motor capacity to press the response button. All groups performed a secondary task equally well, hence indicating that our results could not simply be attributed to differences in attention between the groups. Our results show that motor activity, even when it does not play a causal or corrective role, can lead to improved interval timing judgments. PMID:25806813

  12. Trunk muscle activation during golf swing: Baseline and threshold.

    PubMed

    Silva, Luís; Marta, Sérgio; Vaz, João; Fernandes, Orlando; Castro, Maria António; Pezarat-Correia, Pedro

    2013-10-01

    There is a lack of studies regarding EMG temporal analysis during dynamic and complex motor tasks, such as golf swing. The aim of this study is to analyze the EMG onset during the golf swing, by comparing two different threshold methods. Method A threshold was determined using the baseline activity recorded between two maximum voluntary contraction (MVC). Method B threshold was calculated using the mean EMG activity for 1000ms before the 500ms prior to the start of the Backswing. Two different clubs were also studied. Three-way repeated measures ANOVA was used to compare methods, muscles and clubs. Two-way mixed Intraclass Correlation Coefficient (ICC) with absolute agreement was used to determine the methods reliability. Club type usage showed no influence in onset detection. Rectus abdominis (RA) showed the higher agreement between methods. Erector spinae (ES), on the other hand, showed a very low agreement, that might be related to postural activity before the swing. External oblique (EO) is the first being activated, at 1295ms prior impact. There is a similar activation time between right and left muscles sides, although the right EO showed better agreement between methods than left side. Therefore, the algorithms usage is task- and muscle-dependent. PMID:23816264

  13. Motor cortical plasticity in extrinsic hand muscles is determined by the resting thresholds of overlapping representations.

    PubMed

    Mirdamadi, J L; Suzuki, L Y; Meehan, S K

    2016-10-01

    Knowledge of the properties that govern the effectiveness of transcranial magnetic stimulation (TMS) interventions is critical to clinical application. Extrapolation to clinical populations has been limited by high inter-subject variability and a focus on intrinsic muscles of the hand in healthy populations. Therefore, the current study assessed variability of continuous theta burst stimulation (cTBS), a patterned TMS protocol, across an agonist-antagonist pair of extrinsic muscles of the hand. Secondarily, we assessed whether concurrent agonist contraction could enhance the efficacy of cTBS. Motor evoked potentials (MEP) were simultaneously recorded from the agonist flexor (FCR) and antagonist extensor (ECR) carpi radialis before and after cTBS over the FCR hotspot. cTBS was delivered with the FCR relaxed (cTBS-Relax) or during isometric wrist flexion (cTBS-Contract). cTBS-Relax suppressed FCR MEPs evoked from the FCR hotspot. However, the extent of FCR MEP suppression was strongly correlated with the relative difference between FCR and ECR resting motor thresholds. cTBS-Contract decreased FCR suppression but increased suppression of ECR MEPs elicited from the FCR hotspot. The magnitude of ECR MEP suppression following cTBS-Contract was independent of the threshold-amplitude relationships observed with cTBS-Relax. Contraction alone had no effect confirming the effect of cTBS-Contract was driven by the interaction between neuromuscular activity and cTBS. Interactions across muscle representations should be taken into account when predicting cTBS outcomes in healthy and clinical populations. Contraction during cTBS may be a useful means of focusing aftereffects when differences in baseline excitability across overlapping agonist-antagonist cortical representations may mitigate the inhibitory effect of cTBS. PMID:27425211

  14. Left-right differences in motor thresholds after stimulation of the globus pallidus before pallidotomy.

    PubMed

    Berić, A; Sterio, D; Dogali, M; Kelly, P

    1997-08-01

    Left-right upper limb motor threshold differences were found after electrical stimulation of the globus pallidus administered as a neuroprotective measure to avoid lesioning of the internal capsule during stereotactic pallidotomy for treatment of Parkinson's disease. Left sided stimulation resulted in lower thresholds in right handed patients compared with left handed patients. These differences were significant in women, but no significant differences were found in men. In patients undergoing bilateral pallidotomy, the stimulation produced more significant left-right motor threshold differences. In the absence of known sex-related anatomical left-right corticospinal tract differences, the variability was the result of spinal excitability modulations most likely related to handedness. PMID:9285451

  15. Left-right differences in motor thresholds after stimulation of the globus pallidus before pallidotomy

    PubMed Central

    Beric, A; Sterio, D; Dogali, M; Kelly, P

    1997-01-01

    Left-right upper limb motor threshold differences were found after electrical stimulation of the globus pallidus administered as a neuroprotective measure to avoid lesioning of the internal capsule during stereotactic pallidotomy for treatment of Parkinson's disease. Left sided stimulation resulted in lower thresholds in right handed patients compared with left handed patients. These differences were significant in women, but no significant differences were found in men. In patients undergoing bilateral pallidotomy, the stimulation produced more significant left-right motor threshold differences. In the absence of known sex-related anatomical left-right corticospinal tract differences, the variability was the result of spinal excitability modulations most likely related to handedness.

 PMID:9285451

  16. Motor activity under weightless conditions

    NASA Technical Reports Server (NTRS)

    Kasyan, I. I.; Kopanev, V. I.; Cherepakhin, M. A.; Yuganov, Y. M.

    1975-01-01

    The material presented on the motor activity under weightless conditions (brief and long) leads to the conclusion that it is not significantly disrupted, if those being examined are secured at the workplaces. Some discoordination of movement, moderately expressed disruption of the precision of reproduction of assigned muscular forces, etc., were observed. Motor disorders decrease significantly in proportion to the length of stay under weightless conditions. This apparently takes place, as a consequence of formation of a new functional system, adequate to the conditions of weightlessness. Tests on intact and labyrinthectomized animals have demonstrated that signaling from the inner ear receptors is superfluous in weightlessness, since it promotes the onset of disruptions in the combined work of the position analyzers.

  17. Suppression of voluntary motor activity revealed using transcranial magnetic stimulation of the motor cortex in man.

    PubMed Central

    Davey, N J; Romaiguère, P; Maskill, D W; Ellaway, P H

    1994-01-01

    1. Suppression of voluntary muscle activity of hand and arm muscles in response to transcranial magnetic stimulation (TMS) of the motor cortex has been investigated in man. 2. Suppression could be elicited by low levels of TMS without any prior excitatory response. The latency of the suppression was 3-8 ms longer than the excitation observed at a higher stimulus intensity. The duration of the suppression ranged from 8 to 26 ms. 3. A circular stimulating coil was used to determine threshold intensity for excitation and suppression of contraction of thenar muscles in response to TMS at different locations over the motor cortex. The locations for lowest threshold excitation coincided with those for lowest threshold suppression. Suppression was elicited at a lower threshold than excitation at all locations. 4. A figure-of-eight stimulating coil was positioned over the left motor cortex at the lowest threshold point for excitation of the right thenar muscles. The orientation for the lowest threshold excitatory and inhibitory responses was the same for all subjects. That orientation induced a stimulating current travelling in an antero-medial direction. Suppression was invariably elicited at lower thresholds than excitation. 5. When antagonistic muscles (second and third dorsal interosseus) were co-contracted, TMS evoked coincident suppression of voluntary EMG in the two muscles without prior excitation of either muscle. This suggests that the suppression is not mediated via corticospinal activation of spinal interneurones. 6. Test responses to electrical stimulation of the cervical spinal cord were evoked in both relaxed and activated thenar muscles. In the relaxed muscle, prior TMS at an intensity that would suppress voluntary activity failed to influence the test responses, suggesting absence of inhibition at a spinal level. However, in the activated muscle, prior TMS could reduce the test response. This may be explained by disfacilitation of motoneurones due to

  18. Motor Cortex Activity Organizes the Developing Rubrospinal System

    PubMed Central

    Williams, Preston T.J.A.

    2015-01-01

    The corticospinal and rubrospinal systems function in skilled movement control. A key question is how do these systems develop the capacity to coordinate their motor functions and, in turn, if the red nucleus/rubrospinal tract (RN/RST) compensates for developmental corticospinal injury? We used the cat to investigate whether the developing rubrospinal system is shaped by activity-dependent interactions with the developing corticospinal system. We unilaterally inactivated M1 by muscimol microinfusion between postnatal weeks 5 and 7 to examine activity-dependent interactions and whether the RN/RST compensates for corticospinal tract (CST) developmental motor impairments and CST misprojections after M1 inactivation. We examined the RN motor map and RST cervical projections at 7 weeks of age, while the corticospinal system was inactivated, and at 14 weeks, after activity returned. During M1 inactivation, the RN on the same side showed normal RST projections and reduced motor thresholds, suggestive of precocious development. By contrast, the RN on the untreated/active M1 side showed sparse RST projections and an immature motor map. After M1 activity returned later in adolescent cat development, RN on the active M1/CST side continued to show a substantial loss of spinal terminations and an impaired motor map. RN/RST on the inactivated side regressed to a smaller map and fewer axons. Our findings suggest that the developing rubrospinal system is under activity-dependent regulation by the corticospinal system for establishing mature RST connections and RN motor map. The lack of RS compensation on the non-inactivated side can be explained by development of ipsilateral misprojections from the active M1 that outcompete the RST. SIGNIFICANCE STATEMENT Skilled movements reflect the activity of multiple descending motor systems and their interactions with spinal motor circuits. Currently, there is little insight into whether motor systems interact during development to

  19. The Effect of Daily Prefrontal Repetitive Transcranial Magnetic Stimulation Over Several Weeks on Resting Motor Threshold

    PubMed Central

    Zarkowski, Paul; Navarro, Rita; Pavlicova, Martina; George, Mark S.; Avery, David

    2009-01-01

    Background: The resting motor threshold (rMT) is an important factor in the selection of treatment intensity for patients receiving repetitive transcranial magnetic stimulation (rTMS). In many clinical studies to date, due to concerns about potential drift, the rMT has been routinely re-measured weekly or every fifth session. Objective: Our aim is to investigate whether ongoing treatment with rTMS affects the rMT, the degree of change, and whether frequent remeasurement is needed. Methods: Clinical data were drawn from 50 medication free patients receiving treatment for major depression with rTMS in a large U.S. NIH-sponsored multisite study. Four measurements of rMT were obtained including before and after the double blind phase, followed by weekly measurements during the open phase. Active treatment consisted of 75 four second trains of 10Hz stimulation applied over 37.5 minutes with the coil over the left DLPFC at 120% rMT. Results: For the group as a whole, there was no significant change in the rMT during a minimum of 2 weeks of treatment with prefrontal rTMS (p=0.911, one way ANOVA). The average within-subject coefficient of variation was 6.58%. On average the last rMT was 2.45% less than the baseline rMT (range 32.3% increase, 40.6% decrease). Conclusion: Daily left prefrontal rTMS over several weeks as delivered in this trial does not cause systematic changes in rMT. While most subjects had <10% variance in rMT over time, 5 subjects had changes of ∼20% from baseline, raising dosing and safety issues if undetected. We recommend that clinical trials of rTMS have periodic retesting of rMT, especially if the dose is at or near the edge of the TMS safety tables. PMID:20161065

  20. Pulse width dependence of motor threshold and input–output curve characterized with controllable pulse parameter transcranial magnetic stimulation

    PubMed Central

    Peterchev, Angel V.; Goetz, Stefan M.; Westin, Gregory G.; Luber, Bruce; Lisanby, Sarah H.

    2013-01-01

    Objective To demonstrate the use of a novel controllable pulse parameter TMS (cTMS) device to characterize human corticospinal tract physiology. Methods Motor threshold and input-output (IO) curve of right first dorsal interosseus were determined in 26 and 12 healthy volunteers, respectively, at pulse widths of 30, 60, and 120 μs using a custom-built cTMS device. Strength–duration curve rheobase and time constant were estimated from the motor thresholds. IO slope was estimated from sigmoid functions fitted to the IO data. Results All procedures were well tolerated with no seizures or other serious adverse events. Increasing pulse width decreased the motor threshold and increased the pulse energy and IO slope. The average strength–duration curve time constant is estimated to be 196 μs, 95% CI [181 μs, 210 μs]. IO slope is inversely correlated with motor threshold both across and within pulse width. A simple quantitative model explains these dependencies. Conclusions Our strength–duration time constant estimate compares well to published values and may be more accurate given increased sample size and enhanced methodology. Multiplying the IO slope by the motor threshold may provide a sensitive measure of individual differences in corticospinal tract physiology. Significance Pulse parameter control offered by cTMS provides enhanced flexibility that can contribute novel insights in TMS studies. PMID:23434439

  1. Asynchronous recruitment of low-threshold motor units during repetitive, low-current stimulation of the human tibial nerve.

    PubMed

    Dean, Jesse C; Clair-Auger, Joanna M; Lagerquist, Olle; Collins, David F

    2014-01-01

    Motoneurons receive a barrage of inputs from descending and reflex pathways. Much of our understanding about how these inputs are transformed into motor output in humans has come from recordings of single motor units during voluntary contractions. This approach, however, is limited because the input is ill-defined. Herein, we quantify the discharge of soleus motor units in response to well-defined trains of afferent input delivered at physiologically-relevant frequencies. Constant frequency stimulation of the tibial nerve (10-100 Hz for 30 s), below threshold for eliciting M-waves or H-reflexes with a single pulse, recruited motor units in 7/9 subjects. All 25 motor units recruited during stimulation were also recruited during weak (<10% MVC) voluntary contractions. Higher frequencies recruited more units (n = 3/25 at 10 Hz; n = 25/25 at 100 Hz) at shorter latencies (19.4 ± 9.4 s at 10 Hz; 4.1 ± 4.0 s at 100 Hz) than lower frequencies. When a second unit was recruited, the discharge of the already active unit did not change, suggesting that recruitment was not due to increased synaptic drive. After recruitment, mean discharge rate during stimulation at 20 Hz (7.8 Hz) was lower than during 30 Hz (8.6 Hz) and 40 Hz (8.4 Hz) stimulation. Discharge was largely asynchronous from the stimulus pulses with "time-locked" discharge occurring at an H-reflex latency with only a 24% probability. Motor units continued to discharge after cessation of the stimulation in 89% of trials, although at a lower rate (5.8 Hz) than during the stimulation (7.9 Hz). This work supports the idea that the afferent volley evoked by repetitive stimulation recruits motor units through the integration of synaptic drive and intrinsic properties of motoneurons, resulting in "physiological" recruitment which adheres to Henneman's size principle and results in relatively low discharge rates and asynchronous firing. PMID:25566025

  2. Motor patterns during active electrosensory acquisition

    PubMed Central

    Hofmann, Volker; Geurten, Bart R. H.; Sanguinetti-Scheck, Juan I.; Gómez-Sena, Leonel; Engelmann, Jacob

    2014-01-01

    Motor patterns displayed during active electrosensory acquisition of information seem to be an essential part of a sensory strategy by which weakly electric fish actively generate and shape sensory flow. These active sensing strategies are expected to adaptively optimize ongoing behavior with respect to either motor efficiency or sensory information gained. The tight link between the motor domain and sensory perception in active electrolocation make weakly electric fish like Gnathonemus petersii an ideal system for studying sensory-motor interactions in the form of active sensing strategies. Analyzing the movements and electric signals of solitary fish during unrestrained exploration of objects in the dark, we here present the first formal quantification of motor patterns used by fish during electrolocation. Based on a cluster analysis of the kinematic values we categorized the basic units of motion. These were then analyzed for their associative grouping to identify and extract short coherent chains of behavior. This enabled the description of sensory behavior on different levels of complexity: from single movements, over short behaviors to more complex behavioral sequences during which the kinematics alter between different behaviors. We present detailed data for three classified patterns and provide evidence that these can be considered as motor components of active sensing strategies. In accordance with the idea of active sensing strategies, we found categorical motor patterns to be modified by the sensory context. In addition these motor patterns were linked with changes in the temporal sampling in form of differing electric organ discharge frequencies and differing spatial distributions. The ability to detect such strategies quantitatively will allow future research to investigate the impact of such behaviors on sensing. PMID:24904337

  3. Fuzzy Behavior Modulation with Threshold Activation for Autonomous Vehicle Navigation

    NASA Technical Reports Server (NTRS)

    Tunstel, Edward

    2000-01-01

    This paper describes fuzzy logic techniques used in a hierarchical behavior-based architecture for robot navigation. An architectural feature for threshold activation of fuzzy-behaviors is emphasized, which is potentially useful for tuning navigation performance in real world applications. The target application is autonomous local navigation of a small planetary rover. Threshold activation of low-level navigation behaviors is the primary focus. A preliminary assessment of its impact on local navigation performance is provided based on computer simulations.

  4. Evaluation of sensitivity, motor and pain thresholds across the menstrual cycle through medium-frequency transcutaneous electrical nerve stimulation

    PubMed Central

    de Brito Barbosa, Mariana; de Oliveira Guirro, Elaine Caldeira; Nunes, Fabiana Roberta

    2013-01-01

    OBJECTIVES: The aim of this study was to identify variations in nervous thresholds in different phases of the menstrual cycle in eumenorrheic women and users of oral contraceptives. METHOD: An observational study was performed including 56 volunteers, consisting of 30 eumenorrheic women who were non-users of oral contraceptives and 26 users of oral contraceptives. An electrical stimulator was employed to assess their nervous thresholds, with pulses applied at a fixed frequency of 2,500 Hz, modulated at 50 Hz, with phase variances of 20 μs, 50 μs and 100 μs. Sensitivity, motor and pain thresholds were evaluated during five menstrual cycle phases: phase 1 - menstrual, phase 2 - follicular, phase 3 - ovulatory, phase 4 - luteal and phase 5 - premenstrual. RESULTS: The results indicated low sensitivity thresholds of 100 μs for non-users of oral contraceptives and 50 μs for oral contraceptive users in phase 5. Low motor thresholds of 20 μs, 50 μs and 100 μs were observed for non-users of oral contraceptives in phase 5, while that of oral contraceptive users was 100 μs. Finally, a low pain threshold of 100 μs was observed in phase 5, but only in the oral contraceptive group. CONCLUSION: Nervous thresholds vary systematically across the phases of the menstrual cycle, with or without the use of oral contraceptives. These variations should be taken into account during research performed in women. PMID:23917651

  5. Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.

    PubMed

    Ye, Xin; Beck, Travis W; DeFreitas, Jason M; Wages, Nathan P

    2015-04-01

    The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss. PMID:25514631

  6. Activities to Develop Your Students' Motor Skills.

    ERIC Educational Resources Information Center

    Eastman, Mary Kay; Safran, Joan S.

    1986-01-01

    Instructions and illustrations support this discussion of learning activities designed to remediate deficiences and build skills in balance and/or motor skills for mildly handicapped students who may not have access to physical therapy or adaptive physical education. Appropriate for both regular and special classes, activities include arm…

  7. T Cell Activation Thresholds are Affected by Gravitational

    NASA Technical Reports Server (NTRS)

    Adams, Charley; Gonzalez, M.; Nelman-Gonzalez, M.

    1999-01-01

    T cells stimulated in space flight by various mitogenic signals show a dramatic reduction in proliferation and expression of early activation markers. Similar results are also obtained in a ground based model of microgravity, clinorotation, which provides a vector-averaged reduction of the apparent gravity on cells without significant shear force. Here we demonstrate that T cell inhibition is due to an increase in the required threshold for activation. Dose response curves indicate that cells activated during clinorotation require higher stimulation to achieve the same level of activation, as measured by CD69 expression. Interleukin 2 receptor expression, and DNA synthesis. The amount of stimulation necessary for 50% activation is 5 fold in the clinostat relative to static. Correlation of TCR internalization with activation also exhibit a dramatic right shift in clinorotation, demonstrating unequivocally that signal transduction mechanism independent of TCR triggering account for the increased activation threshold. Previous results from space flight experiments are consistent with the dose response curves obtained for clinorotation. Activation thresholds are important aspects of T cell memory, autoimmunity and tolerance Clinorotation is a useful, noninvasive tool for the study of cellular and biochemical event regulating T cell activation threshold and the effects of gravitation forces on these systems.

  8. Low-Threshold Active Teaching Methods for Mathematic Instruction

    ERIC Educational Resources Information Center

    Marotta, Sebastian M.; Hargis, Jace

    2011-01-01

    In this article, we present a large list of low-threshold active teaching methods categorized so the instructor can efficiently access and target the deployment of conceptually based lessons. The categories include teaching strategies for lecture on large and small class sizes; student action individually, in pairs, and groups; games; interaction…

  9. Enhanced Multisensory Integration and Motor Reactivation after Active Motor Learning of Audiovisual Associations

    ERIC Educational Resources Information Center

    Butler, Andrew J.; James, Thomas W.; James, Karin Harman

    2011-01-01

    Everyday experience affords us many opportunities to learn about objects through multiple senses using physical interaction. Previous work has shown that active motor learning of unisensory items enhances memory and leads to the involvement of motor systems during subsequent perception. However, the impact of active motor learning on subsequent…

  10. INTERLABORATORY COMPARISON OF MOTOR ACTIVITY EXPERIMENTS: IMPLICATIONS FOR NEUROTOXICOLOGICAL ASSESSMENTS

    EPA Science Inventory

    Motor activity is an important functional measure used in neurotoxicology the effects of chemicals on motor activity, however, may depend on variables such as, type of measurement apparatus, physical and environmental testing conditions, and many other experimental protocol and o...

  11. Motor imagery muscle contraction strength influences spinal motor neuron excitability and cardiac sympathetic nerve activity

    PubMed Central

    Bunno, Yoshibumi; Suzuki, Toshiaki; Iwatsuki, Hiroyasu

    2015-01-01

    [Purpose] The aim of this study was to investigate the changes in spinal motor neuron excitability and autonomic nervous system activity during motor imagery of isometric thenar muscle activity at 10% and 50% maximal voluntary contraction (MVC). [Methods] The F-waves and low frequency/high frequency (LF/HF) ratio were recorded at rest, during motor imagery, and post-trial. For motor imagery trials, subjects were instructed to imagine thenar muscle activity at 10% and 50% MVC while holding the sensor of a pinch meter for 5 min. [Results] The F-waves and LF/HF ratio during motor imagery at 50% MVC were significantly increased compared with those at rest, whereas those during motor imagery at 10% MVC were not significantly different from those at rest. The relative values of the F/M amplitude ratio during motor imagery at 50% MVC were significantly higher than those at 10% MVC. The relative values of persistence and the LF/HF ratio during motor imagery were similar during motor imagery at the two muscle contraction strengths. [Conclusion] Motor imagery can increase the spinal motor neuron excitability and cardiac sympathetic nerve activity. Motor imagery at 50% MVC may be more effective than motor imagery at 10% MVC. PMID:26834354

  12. High-sensitivity active pixel sensor with variable threshold photodetector

    NASA Astrophysics Data System (ADS)

    Jo, Sung-Hyun; Bae, Myunghan; Choi, Byoung-Soo; Lyu, Hong-Kun; Shin, Jang-Kyoo

    2015-05-01

    A novel high-sensitivity active pixel sensor (APS) with a variable threshold photodetector has been presented and for the first time, a simple SPICE model for the variable threshold photodetector is presented. Its SPICE model is in good agreement with measurements and is more simpler than the conventional model. The proposed APS has a gate/body-tied PMOSFET-type photodetector with an overlapping control gate that makes it possible to control the sensitivity of the proposed APS. It is a hybrid device composed of a metal-oxide-semiconductor field-effect transistor (MOSFET), a lateral bipolar junction transistor (BJT) and a vertical BJT. Using sufficient overlapping control gate bias to operate the MOSFET in inversion mode, the variable threshold photodetector allows for increasing the photocurrent gain by 105 at low light intensities when the control gate bias is -3 V. Thus, the proposed APS with a variable threshold photodetector has better low-light-level sensitivity than the conventional APS operating mode, and it has a variable sensitivity which is determined by the control gate bias. The proposed sensor has been fabricated by using 0.35 μm 2-poly 4-metal standard complementary MOS (CMOS) process and its characteristics have been evaluated.

  13. Motor Behavior Activates Bergmann Glial Networks

    PubMed Central

    Nimmerjahn, Axel; Mukamel, Eran A.; Schnitzer, Mark J.

    2010-01-01

    SUMMARY Although it is firmly established neuronal activity is a prime determinant of animal behavior, relationships between astrocytic excitation and animal behavior have remained opaque. Cerebellar Bergmann glia are radial astrocytes that are implicated in motor behavior and exhibit Ca2+-excitation. However, Ca2+-excitation in these cells has not previously been studied in behaving animals. Using two-photon microscopy we found that Bergmann glia exhibit three forms of Ca2+-excitation in awake behaving mice. Two of these are ongoing within the cerebellar vermis. During locomotor performance concerted Ca2+-excitation arises in networks of at least hundreds of Bergmann glia extending across several hundred microns or more. Concerted Ca2+-excitation was abolished by anesthesia or blockade of either neural activity or glutamatergic transmission. Thus, large networks of Bergmann glia can be activated by specific animal behaviors and undergo excitation of sufficient magnitude to potentially initiate macroscopic changes in brain dynamics or blood flow. PMID:19447095

  14. Suppression of Abdominal Motor Activity during Swallowing in Cats and Humans

    PubMed Central

    Pitts, Teresa; Gayagoy, Albright G.; Rose, Melanie J.; Poliacek, Ivan; Condrey, Jillian A.; Musslewhite, M. Nicholas; Shen, Tabitha Y.; Davenport, Paul W.; Bolser, Donald C

    2015-01-01

    Diseases affecting pulmonary mechanics often result in changes to the coordination of swallow and breathing. We hypothesize that during times of increased intrathoracic pressure, swallow suppresses ongoing expiratory drive to ensure bolus transport through the esophagus. To this end, we sought to determine the effects of swallow on abdominal electromyographic (EMG) activity during expiratory threshold loading in anesthetized cats and in awake-healthy adult humans. Expiratory threshold loads were applied to recruit abdominal motor activity during breathing, and swallow was triggered by infusion of water into the mouth. In both anesthetized cats and humans, expiratory cycles which contained swallows had a significant reduction in abdominal EMG activity, and a greater percentage of swallows were produced during inspiration and/or respiratory phase transitions. These results suggest that: a) spinal expiratory motor pathways play an important role in the execution of swallow, and b) a more complex mechanical relationship exists between breathing and swallow than has previously been envisioned. PMID:26020240

  15. Fine Motor Activities Program to Promote Fine Motor Skills in a Case Study of Down's Syndrome.

    PubMed

    Lersilp, Suchitporn; Putthinoi, Supawadee; Panyo, Kewalin

    2016-01-01

    Children with Down's syndrome have developmental delays, particularly regarding cognitive and motor development. Fine motor skill problems are related to motor development. They have impact on occupational performances in school-age children with Down's syndrome because they relate to participation in school activities, such as grasping, writing, and carrying out self-care duties. This study aimed to develop a fine motor activities program and to examine the efficiency of the program that promoted fine motor skills in a case study of Down's syndrome. The case study subject was an 8 -year-old male called Kai, who had Down's syndrome. He was a first grader in a regular school that provided classrooms for students with special needs. This study used the fine motor activities program with assessment tools, which included 3 subtests of the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2) that applied to Upper-limb coordination, Fine motor precision and Manual dexterity; as well as the In-hand Manipulation Checklist, and Jamar Hand Dynamometer Grip Test. The fine motor activities program was implemented separately and consisted of 3 sessions of 45 activities per week for 5 weeks, with each session taking 45 minutes. The results showed obvious improvement of fine motor skills, including bilateral hand coordination, hand prehension, manual dexterity, in-hand manipulation, and hand muscle strength. This positive result was an example of a fine motor intervention program designed and developed for therapists and related service providers in choosing activities that enhance fine motor skills in children with Down's syndrome. PMID:27357876

  16. Recruitment of rat diaphragm motor units across motor behaviors with different levels of diaphragm activation

    PubMed Central

    Seven, Yasin B.; Mantilla, Carlos B.

    2014-01-01

    Phrenic motor neurons are recruited across a range of motor behaviors to generate varying levels of diaphragm muscle (DIAm) force. We hypothesized that DIAm motor units are recruited in a fixed order across a range of motor behaviors of varying force levels, consistent with the Henneman Size Principle. Single motor unit action potentials and compound DIAm EMG activities were recorded in anesthetized, neurally intact rats across different motor behaviors, i.e., eupnea, hypoxia-hypercapnia (10% O2 and 5% CO2), deep breaths, sustained airway occlusion, and sneezing. Central drive [estimated by root-mean-squared (RMS) EMG value 75 ms after the onset of EMG activity (RMS75)], recruitment delay, and onset discharge frequencies were similar during eupnea and hypoxia-hypercapnia. Compared with eupnea, central drive increased (∼25%) during deep breaths, and motor units were recruited ∼12 ms earlier (P < 0.01). During airway occlusion, central drive was ∼3 times greater, motor units were recruited ∼30 ms earlier (P < 0.01), and motor unit onset discharge frequencies were significantly higher (P < 0.01). Recruitment order of motor unit pairs observed during eupnea was maintained for 98%, 87%, and 84% of the same pairs recorded during hypoxia-hypercapnia, deep breaths, and airway occlusion, respectively. Reversals in motor unit recruitment order were observed primarily if motor unit pairs were recruited <20 ms apart. These results are consistent with DIAm motor unit recruitment order being determined primarily by the intrinsic size-dependent electrophysiological properties of phrenic motor neurons. PMID:25257864

  17. Neural activation in cognitive motor processes: comparing motor imagery and observation of gymnastic movements.

    PubMed

    Munzert, Jörn; Zentgraf, Karen; Stark, Rudolf; Vaitl, Dieter

    2008-07-01

    The simulation concept suggested by Jeannerod (Neuroimage 14:S103-S109, 2001) defines the S-states of action observation and mental simulation of action as action-related mental states lacking overt execution. Within this framework, similarities and neural overlap between S-states and overt execution are interpreted as providing the common basis for the motor representations implemented within the motor system. The present brain imaging study compared activation overlap and differential activation during mental simulation (motor imagery) with that while observing gymnastic movements. The fMRI conjunction analysis revealed overlapping activation for both S-states in primary motor cortex, premotor cortex, and the supplementary motor area as well as in the intraparietal sulcus, cerebellar hemispheres, and parts of the basal ganglia. A direct contrast between the motor imagery and observation conditions revealed stronger activation for imagery in the posterior insula and the anterior cingulate gyrus. The hippocampus, the superior parietal lobe, and the cerebellar areas were differentially activated in the observation condition. In general, these data corroborate the concept of action-related S-states because of the high overlap in core motor as well as in motor-related areas. We argue that differential activity between S-states relates to task-specific and modal information processing. PMID:18425505

  18. Motor Neuron Activation in Peripheral Nerves Using Infrared Neural Stimulation

    PubMed Central

    Peterson, EJ; Tyler, DJ

    2014-01-01

    Objective Localized activation of peripheral axons may improve selectivity of peripheral nerve interfaces. Infrared neural stimulation (INS) employs localized delivery to activate neural tissue. This study investigated INS to determine whether localized delivery limited functionality in larger mammalian nerves. Approach The rabbit sciatic nerve was stimulated extraneurally with 1875 nm-wavelength infrared light, electrical stimulation, or a combination of both. Infrared-sensitive regions (ISR) of the nerve surface and electromyogram (EMG) recruitment of the Medial Gastrocnemius, Lateral Gastrocnemius, Soleus, and Tibialis Anterior were the primary output measures. Stimulation applied included infrared-only, electrical-only, and combined infrared and electrical. Main results 81% of nerves tested were sensitive to INS, with 1.7± 0.5 ISR detected per nerve. INS was selective to a single muscle within 81% of identified ISR. Activation energy threshold did not change significantly with stimulus power, but motor activation decreased significantly when radiant power was decreased. Maximum INS levels typically recruited up to 2–9% of any muscle. Combined infrared and electrical stimulation differed significantly from electrical recruitment in 7% of cases. Significance The observed selectivity of INS indicates it may be useful in augmenting rehabilitation, but significant challenges remain in increasing sensitivity and response magnitude to improve the functionality of INS. PMID:24310923

  19. Motor neuron activation in peripheral nerves using infrared neural stimulation

    NASA Astrophysics Data System (ADS)

    Peterson, E. J.; Tyler, D. J.

    2014-02-01

    Objective. Localized activation of peripheral axons may improve selectivity of peripheral nerve interfaces. Infrared neural stimulation (INS) employs localized delivery to activate neural tissue. This study investigated INS to determine whether localized delivery limited functionality in larger mammalian nerves. Approach. The rabbit sciatic nerve was stimulated extraneurally with 1875 nm wavelength infrared light, electrical stimulation, or a combination of both. Infrared-sensitive regions (ISR) of the nerve surface and electromyogram (EMG) recruitment of the Medial Gastrocnemius, Lateral Gastrocnemius, Soleus, and Tibialis Anterior were the primary output measures. Stimulation applied included infrared-only, electrical-only, and combined infrared and electrical. Main results. 81% of nerves tested were sensitive to INS, with 1.7 ± 0.5 ISR detected per nerve. INS was selective to a single muscle within 81% of identified ISR. Activation energy threshold did not change significantly with stimulus power, but motor activation decreased significantly when radiant power was decreased. Maximum INS levels typically recruited up to 2-9% of any muscle. Combined infrared and electrical stimulation differed significantly from electrical recruitment in 7% of cases. Significance. The observed selectivity of INS indicates that it may be useful in augmenting rehabilitation, but significant challenges remain in increasing sensitivity and response magnitude to improve the functionality of INS.

  20. Motor Cortex Activity During Functional Motor Skills: An fNIRS Study.

    PubMed

    Nishiyori, Ryota; Bisconti, Silvia; Ulrich, Beverly

    2016-01-01

    Assessments of brain activity during motor task performance have been limited to fine motor movements due to technological constraints presented by traditional neuroimaging techniques, such as functional magnetic resonance imaging. Functional near-infrared spectroscopy (fNIRS) offers a promising method by which to overcome these constraints and investigate motor performance of functional motor tasks. The current study used fNIRS to quantify hemodynamic responses within the primary motor cortex in twelve healthy adults as they performed unimanual right, unimanual left, and bimanual reaching, and stepping in place. Results revealed that during both unimanual reaching tasks, the contralateral hemisphere showed significant activation in channels located approximately 3 cm medial to the C3 (for right-hand reach) and C4 (for left-hand reach) landmarks. Bimanual reaching and stepping showed activation in similar channels, which were located bilaterally across the primary motor cortex. The medial channels, surrounding Cz, showed significantly higher activations during stepping when compared to bimanual reaching. Our results extend the viability of fNIRS to study motor function and build a foundation for future investigation of motor development in infants during nascent functional behaviors and monitor how they may change with age or practice. PMID:26243304

  1. Modulation of motor activity by cutaneous input: inhibition of the magnetic motor evoked potential by digital electrical stimulation.

    PubMed

    Clouston, P D; Kiers, L; Menkes, D; Sander, H; Chiappa, K; Cros, D

    1995-04-01

    We examined the inhibitory effect of a brief train of digital (D2) electrical stimuli at 4 times perception threshold on transcranial magnetic motor evoked potentials (MEPs) recorded from abductor pollicis brevis (APB) and flexor carpi radialis (FCR) muscles ipsilateral to the side of D2 stimulation. We compared this to the inhibitory effect of ipsilateral D2 stimulation on averaged rectified EMG recorded at 10% maximum voluntary contraction and on F-responses and H-reflexes recorded from these same muscles. We also compared MEPs recorded following D2 stimulation just above perception threshold to MEPs following higher intensity D2 stimulation. As well, we assessed the effect of preceding D2 stimulation on MEPs recorded from a relaxed versus tonically contracted hand muscle. D2 stimulation elicited a triphasic response of modest MEP facilitation followed by inhibition and further facilitation. The duration and onset of MEP inhibition correlated with those of the initial period of rectified EMG inhibition, however, the magnitude of MEP inhibition was generally less than the magnitude of EMG inhibition, consistent with a greater inhibitory effect of digital afferents on smaller motor neurons. MEPs were not facilitated during the rebound of EMG activity (the E2 period) that usually followed the initial period of EMG inhibition (I1 period). The behavior of H-reflexes and F-responses following ipsilateral D2 stimulation suggested that inhibition of both EMG and MEPs is not mediated via presynaptic inhibition of Ia afferents, and that inhibition is augmented by descending rather than segmental input to spinal motor neurons. Tonic contraction of the target muscle during D2 stimulation decreased the inhibitory effect of the preceding digital stimulus possibly due to recruitment of larger spinal motor neurons less likely to be inhibited by cutaneous input. PMID:7537203

  2. Activity of latissimus dorsi muscle during inspiratory threshold loads.

    PubMed

    Orozco-Levi, M; Gea, J; Monells, J; Aran, X; Aguar, M C; Broquetas, J M

    1995-03-01

    The ability of the latissimus dorsi muscle (LD) to participate as an accessory inspiratory muscle has been the subject of controversy. Electromyographic (EGM) activity of LD was evaluated in 11 healthy subjects (aged 30 +/- 2 yrs; forced expiratory volume in one second (FEV1) 106 +/- 5% predicted; maximal inspiratory pressure (Pmax), 120 +/- 6 cmH2O) under different breathing conditions. The ipsilateral biceps brachii was chosen as the control muscle. The EMG was recorded from surface electrodes, but needle electrodes were also used for LD evaluation in a subset of three subjects. The EMG signal from both muscles was recorded simultaneously, rectified and integrated, with subtraction of the electrocardiographic signal. Situations evaluated were: 1) maximal voluntary contraction (MVC); 2) apnoea; and 3) breathing under progressive inspiratory threshold loads (20-100% Pmax, at 20% intervals). A close relationship was evident between LD recordings from surface and needle electrodes (r = 0.975). Activity of LD at baseline was 1.8 +/- 0.4% MVC, and showed a phasic increase during inspiration under loads. This change had a linear tendency and was significant for loads corresponding to 40, 60, 80 and 100% of Pmax when compared to the control muscle. At this latter level, LD activity was equivalent to 32 +/- 5% MVC (range 11-61%), whereas mean activity of the control muscle was less than 7.5% MVC.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7789491

  3. Dopamine Promotes Motor Cortex Plasticity and Motor Skill Learning via PLC Activation

    PubMed Central

    Rioult-Pedotti, Mengia-Seraina; Pekanovic, Ana; Atiemo, Clement Osei; Marshall, John; Luft, Andreas Rüdiger

    2015-01-01

    Dopaminergic neurons in the ventral tegmental area, the major midbrain nucleus projecting to the motor cortex, play a key role in motor skill learning and motor cortex synaptic plasticity. Dopamine D1 and D2 receptor antagonists exert parallel effects in the motor system: they impair motor skill learning and reduce long-term potentiation. Traditionally, D1 and D2 receptor modulate adenylyl cyclase activity and cyclic adenosine monophosphate accumulation in opposite directions via different G-proteins and bidirectionally modulate protein kinase A (PKA), leading to distinct physiological and behavioral effects. Here we show that D1 and D2 receptor activity influences motor skill acquisition and long term synaptic potentiation via phospholipase C (PLC) activation in rat primary motor cortex. Learning a new forelimb reaching task is severely impaired in the presence of PLC, but not PKA-inhibitor. Similarly, long term potentiation in motor cortex, a mechanism involved in motor skill learning, is reduced when PLC is inhibited but remains unaffected by the PKA inhibitor. Skill learning deficits and reduced synaptic plasticity caused by dopamine antagonists are prevented by co-administration of a PLC agonist. These results provide evidence for a role of intracellular PLC signaling in motor skill learning and associated cortical synaptic plasticity, challenging the traditional view of bidirectional modulation of PKA by D1 and D2 receptors. These findings reveal a novel and important action of dopamine in motor cortex that might be a future target for selective therapeutic interventions to support learning and recovery of movement resulting from injury and disease. PMID:25938462

  4. Twist1 activity thresholds define multiple functions in limb development

    PubMed Central

    Krawchuk, Dayana; Weiner, Shoshana J.; Chen, You-Tzung; Lu, Benson; Costantini, Frank; Behringer, Richard R.; Laufer, Ed

    2010-01-01

    Summary The basic helix-loop-helix transcription factor Twist1 is essential for normal limb development. Twist1−/− embryos die at midgestation. However, studies on early limb buds found that Twist1−/− mutant limb mesenchyme has an impaired response to FGF signaling from the apical ectodermal ridge, which disrupts the feedback loop between the mesenchyme and AER, and reduces and shifts anteriorly Shh expression in the zone of polarizing activity. We have combined Twist1 null, hypomorph and conditional alleles to generate a Twist1 allelic series that survives to birth. As Twist1 activity is reduced, limb skeletal defects progress from preaxial polydactyly to girdle reduction combined with hypoplasia, aplasia or mirror symmetry of all limb segments. With reduced Twist1 activity there is striking and progressive upregulation of ectopic Shh expression in the anterior of the limb, combined with an anterior shift in the posterior Shh domain, which is expressed at normal intensity, and loss of the posterior AER. Consequently limb outgrowth is initially impaired, before an ectopic anterior Shh domain expands the AER, promoting additional growth and repatterning. Reducing the dosage of FGF targets of the Etv gene family, which are known repressors of Shh expression in the anterior limb mesenchyme, strongly enhances the anterior skeletal phenotype. Conversely this and other phenotypes are suppressed by reducing the dosage of the Twist1 antagonist Hand2. Our data support a model whereby multiple Twist1 activity thresholds contribute to early limb bud patterning, and suggest how particular combinations of skeletal defects result from differing amounts of Twist1 activity. PMID:20732316

  5. Reduced motor cortex activity during movement preparation following a period of motor skill practice.

    PubMed

    Wright, David J; Holmes, Paul; Di Russo, Francesco; Loporto, Michela; Smith, Dave

    2012-01-01

    Experts in a skill produce movement-related cortical potentials (MRCPs) of smaller amplitude and later onset than novices. This may indicate that, following long-term training, experts require less effort to plan motor skill performance. However, no longitudinal evidence exists to support this claim. To address this, EEG was used to study the effect of motor skill training on cortical activity related to motor planning. Ten non-musicians took part in a 5-week training study learning to play guitar. At week 1, the MRCP was recorded from motor areas whilst participants played the G Major scale. Following a period of practice of the scale, the MRCP was recorded again at week 5. Results showed that the amplitude of the later pre-movement components were smaller at week 5 compared to week 1. This may indicate that, following training, less activity at motor cortex sites is involved in motor skill preparation. This supports claims for a more efficient motor preparation following motor skill training. PMID:23251647

  6. Motor imagery of hand actions: Decoding the content of motor imagery from brain activity in frontal and parietal motor areas.

    PubMed

    Pilgramm, Sebastian; de Haas, Benjamin; Helm, Fabian; Zentgraf, Karen; Stark, Rudolf; Munzert, Jörn; Krüger, Britta

    2016-01-01

    How motor maps are organized while imagining actions is an intensely debated issue. It is particularly unclear whether motor imagery relies on action-specific representations in premotor and posterior parietal cortices. This study tackled this issue by attempting to decode the content of motor imagery from spatial patterns of Blood Oxygen Level Dependent (BOLD) signals recorded in the frontoparietal motor imagery network. During fMRI-scanning, 20 right-handed volunteers worked on three experimental conditions and one baseline condition. In the experimental conditions, they had to imagine three different types of right-hand actions: an aiming movement, an extension-flexion movement, and a squeezing movement. The identity of imagined actions was decoded from the spatial patterns of BOLD signals they evoked in premotor and posterior parietal cortices using multivoxel pattern analysis. Results showed that the content of motor imagery (i.e., the action type) could be decoded significantly above chance level from the spatial patterns of BOLD signals in both frontal (PMC, M1) and parietal areas (SPL, IPL, IPS). An exploratory searchlight analysis revealed significant clusters motor- and motor-associated cortices, as well as in visual cortices. Hence, the data provide evidence that patterns of activity within premotor and posterior parietal cortex vary systematically with the specific type of hand action being imagined. PMID:26452176

  7. Design, Synthesis, and Monitoring of Light-Activated Motorized Nanomachines

    NASA Astrophysics Data System (ADS)

    Chiang, Pinn-Tsong

    Our group has developed a family of single molecules termed nanocars, which are aimed at performing controllable motion on surfaces. In this work, a series of light-activated motorized nanomachines incorporated with a MHz frequency light-activated unidirectional rotary motor were designed and synthesized. We hope the light-activated motor can serve as the powering unit for the nanomachines, and perform controllable translational motion on surfaces or in solution. A series of motorized nanovehicles intended for scanning tunneling microscopy (STM) imaging were designed and synthesized. A p-carborane-wheeled motorized nanocar was synthesized and monitored by STM. Single-molecule imaging was accomplished on a Cu(111) surface. However, further manipulations did lead to motor induced lateral motion. We attributed this result to the strong molecule-surface interactions between the p-carborane-wheeled nanocar and the Cu(111) surface and possible energy transfer between the rotary motor and the Cu(111) surface. To fine-tune the molecule-surface interactions, an adamantane-wheeled motorized nanocar and a three-wheel nanoroadster were designed and synthesized. In addition, the STM substrates will be varied and different combinations of molecule-surface interactions will be studied. As a complimentary imaging method to STM, single-molecule fluorescence microscopy (SMFM) also provides single-molecule level resolution. Unlike STM experiment requires ultra-high vacuum and conductive substrate, SMFM experiment is conducted at ambient conditions and uses non-conductive substrate. This imaging method allows us to study another category of molecule-surface interactions. We plan to design a fluorescent motorized nanocar that is suitable for SMFM studies. However, both the motor and fluorophore are photochemically active molecules. In proximity, some undesired energy transfer or interference could occur. A cyanine 5- (cy5-) tagged motorized nanocar incorporated with the MHz motor was

  8. A structural pathway for activation of the kinesin motor ATPase

    PubMed Central

    Yun, Mikyung; Zhang, Xiaohua; Park, Cheon-Gil; Park, Hee-Won; Endow, Sharyn A.

    2001-01-01

    Molecular motors move along actin or microtubules by rapidly hydrolyzing ATP and undergoing changes in filament-binding affinity with steps of the nucleotide hydrolysis cycle. It is generally accepted that motor binding to its filament greatly increases the rate of ATP hydrolysis, but the structural changes in the motor associated with ATPase activation are not known. To identify the conformational changes underlying motor movement on its filament, we solved the crystal structures of three kinesin mutants that decouple nucleotide and microtubule binding by the motor, and block microtubule-activated, but not basal, ATPase activity. Conformational changes in the structures include a disordered loop and helices in the switch I region and a visible switch II loop, which is disordered in wild-type structures. Switch I moved closer to the bound nucleotide in two mutant structures, perturbing water-mediated interactions with the Mg2+. This could weaken Mg2+ binding and accelerate ADP release to activate the motor ATPase. The structural changes we observe define a signaling pathway within the motor for ATPase activation that is likely to be essential for motor movement on microtubules. PMID:11387196

  9. Cortical activity during motor execution, motor imagery, and imagery-based online feedback

    PubMed Central

    Miller, Kai J.; Schalk, Gerwin; Fetz, Eberhard E.; den Nijs, Marcel; Ojemann, Jeffrey G.; Rao, Rajesh P. N.

    2010-01-01

    Imagery of motor movement plays an important role in learning of complex motor skills, from learning to serve in tennis to perfecting a pirouette in ballet. What and where are the neural substrates that underlie motor imagery-based learning? We measured electrocorticographic cortical surface potentials in eight human subjects during overt action and kinesthetic imagery of the same movement, focusing on power in “high frequency” (76–100 Hz) and “low frequency” (8–32 Hz) ranges. We quantitatively establish that the spatial distribution of local neuronal population activity during motor imagery mimics the spatial distribution of activity during actual motor movement. By comparing responses to electrocortical stimulation with imagery-induced cortical surface activity, we demonstrate the role of primary motor areas in movement imagery. The magnitude of imagery-induced cortical activity change was ∼25% of that associated with actual movement. However, when subjects learned to use this imagery to control a computer cursor in a simple feedback task, the imagery-induced activity change was significantly augmented, even exceeding that of overt movement. PMID:20160084

  10. The origin of word-related motor activity.

    PubMed

    Papeo, Liuba; Lingnau, Angelika; Agosta, Sara; Pascual-Leone, Alvaro; Battelli, Lorella; Caramazza, Alfonso

    2015-06-01

    Conceptual processing of verbs consistently recruits the left posterior middle temporal gyrus (lpMTG). The left precentral motor cortex also responds to verbs, with higher activity for action than nonaction verbs. The early timing of this effect has suggested that motor features of words' meaning are accessed directly, bypassing access to conceptual representations in lpMTG. An alternative hypothesis is that the retrieval of conceptual representations in lpMTG is necessary to drive more specific, motor-related representations in the precentral gyrus. To test these hypotheses, we first showed that repetitive transcranial magnetic stimulation (rTMS) applied to the verb-preferring lpMTG site selectively impoverished the semantic processing of verbs. In a second experiment, rTMS perturbation of lpMTG, relative to no stimulation (no-rTMS), eliminated the action-nonaction verb distinction in motor activity, as indexed by motor-evoked potentials induced in peripheral muscles with single-pulse TMS over the left primary motor cortex. rTMS pertubation of an occipital control site, relative to no-rTMS, did not affect the action-nonaction verb distinction in motor activity, but the verb contrast did not differ reliably from the lpMTG effect. The results show that lpMTG carries core semantic information necessary to drive the activation of specific (motor) features in the precentral gyrus. PMID:24421174

  11. Learning new gait patterns: Exploratory muscle activity during motor learning is not predicted by motor modules.

    PubMed

    Ranganathan, Rajiv; Krishnan, Chandramouli; Dhaher, Yasin Y; Rymer, William Z

    2016-03-21

    The motor module hypothesis in motor control proposes that the nervous system can simplify the problem of controlling a large number of muscles in human movement by grouping muscles into a smaller number of modules. Here, we tested one prediction of the modular organization hypothesis by examining whether there is preferential exploration along these motor modules during the learning of a new gait pattern. Healthy college-aged participants learned a new gait pattern which required increased hip and knee flexion during the swing phase while walking in a lower-extremity robot (Lokomat). The new gait pattern was displayed as a foot trajectory in the sagittal plane and participants attempted to match their foot trajectory to this template. We recorded EMG from 8 lower-extremity muscles and we extracted motor modules during both baseline walking and target-tracking using non-negative matrix factorization (NMF). Results showed increased trajectory variability in the first block of learning, indicating that participants were engaged in exploratory behavior. Critically, when we examined the muscle activity during this exploratory phase, we found that the composition of motor modules changed significantly within the first few strides of attempting the new gait pattern. The lack of persistence of the motor modules under even short time scales suggests that motor modules extracted during locomotion may be more indicative of correlated muscle activity induced by the task constraints of walking, rather than reflecting a modular control strategy. PMID:26916510

  12. Motor skill learning requires active central myelination.

    PubMed

    McKenzie, Ian A; Ohayon, David; Li, Huiliang; de Faria, Joana Paes; Emery, Ben; Tohyama, Koujiro; Richardson, William D

    2014-10-17

    Myelin-forming oligodendrocytes (OLs) are formed continuously in the healthy adult brain. In this work, we study the function of these late-forming cells and the myelin they produce. Learning a new motor skill (such as juggling) alters the structure of the brain's white matter, which contains many OLs, suggesting that late-born OLs might contribute to motor learning. Consistent with this idea, we show that production of newly formed OLs is briefly accelerated in mice that learn a new skill (running on a "complex wheel" with irregularly spaced rungs). By genetically manipulating the transcription factor myelin regulatory factor in OL precursors, we blocked production of new OLs during adulthood without affecting preexisting OLs or myelin. This prevented the mice from mastering the complex wheel. Thus, generation of new OLs and myelin is important for learning motor skills. PMID:25324381

  13. Spinal segment-specific transcutaneous stimulation differentially shapes activation pattern among motor pools in humans.

    PubMed

    Sayenko, Dimitry G; Atkinson, Darryn A; Dy, Christine J; Gurley, Katelyn M; Smith, Valerie L; Angeli, Claudia; Harkema, Susan J; Edgerton, V Reggie; Gerasimenko, Yury P

    2015-06-01

    Transcutaneous and epidural electrical spinal cord stimulation techniques are becoming more valuable as electrophysiological and clinical tools. Recently, we observed selective activation of proximal and distal motor pools during epidural spinal stimulation. In the present study, we hypothesized that the characteristics of recruitment curves obtained from leg muscles will reflect a relative preferential activation of proximal and distal motor pools based on their arrangement along the lumbosacral enlargement. The purpose was to describe the electrophysiological responses to transcutaneous stimulation in leg muscles innervated by motoneurons from different segmental levels. Stimulation delivered along the rostrocaudal axis of the lumbosacral enlargement in the supine position resulted in a selective topographical recruitment of proximal and distal leg muscles, as described by threshold intensity, slope of the recruitment curves, and plateau point intensity and magnitude. Relatively selective recruitment of proximal and distal motor pools can be titrated by optimizing the site and intensity level of stimulation to excite a given combination of motor pools. The slope of the recruitment of particular muscles allows characterization of the properties of afferents projecting to specific motoneuron pools, as well as to the type and size of the motoneurons. The location and intensity of transcutaneous spinal electrical stimulation are critical to target particular neural structures across different motor pools in investigation of specific neuromodulatory effects. Finally, the asymmetry in bilateral evoked potentials is inevitable and can be attributed to both anatomical and functional peculiarities of individual muscles or muscle groups. PMID:25814642

  14. Cortical Activation Changes During Simple Motor Task over Repeated Sessions

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Shuichi; Yamada, Taro; Wada, Yasuhiro

    Recent fMRI studies of human motor function and learning have reported that the magnitude of brain activity involves a decreasing trend over repeated tasks in the absence of improvements in task performance, probably suggesting the effect of habituation. Here we show that similar effect can be detected by NIRS. In experiments, oxygenated hemoglobin (HbO) changes were monitored during a finger tapping task over repeated sessions. Results showed that task-related brain activity exhibited a decreasing trend on motor-related areas over the sessions. These suggest that measurements of NIRS may exhibit the brain-induced trends over repetition of simple motor tasks.

  15. Motor imagery of hand actions: Decoding the content of motor imagery from brain activity in frontal and parietal motor areas

    PubMed Central

    Pilgramm, Sebastian; de Haas, Benjamin; Helm, Fabian; Zentgraf, Karen; Stark, Rudolf; Munzert, Jörn

    2015-01-01

    Abstract How motor maps are organized while imagining actions is an intensely debated issue. It is particularly unclear whether motor imagery relies on action‐specific representations in premotor and posterior parietal cortices. This study tackled this issue by attempting to decode the content of motor imagery from spatial patterns of Blood Oxygen Level Dependent (BOLD) signals recorded in the frontoparietal motor imagery network. During fMRI‐scanning, 20 right‐handed volunteers worked on three experimental conditions and one baseline condition. In the experimental conditions, they had to imagine three different types of right‐hand actions: an aiming movement, an extension–flexion movement, and a squeezing movement. The identity of imagined actions was decoded from the spatial patterns of BOLD signals they evoked in premotor and posterior parietal cortices using multivoxel pattern analysis. Results showed that the content of motor imagery (i.e., the action type) could be decoded significantly above chance level from the spatial patterns of BOLD signals in both frontal (PMC, M1) and parietal areas (SPL, IPL, IPS). An exploratory searchlight analysis revealed significant clusters motor‐ and motor‐associated cortices, as well as in visual cortices. Hence, the data provide evidence that patterns of activity within premotor and posterior parietal cortex vary systematically with the specific type of hand action being imagined. Hum Brain Mapp 37:81–93, 2016. © 2015 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:26452176

  16. Cortical motor activation patterns following hand transplantation and replantation.

    PubMed

    Brenneis, C; Löscher, W N; Egger, K E; Benke, T; Schocke, M; Gabl, M F; Wechselberger, G; Felber, S; Pechlaner, S; Margreiter, R; Piza-Katzer, H; Poewe, W

    2005-10-01

    We studied cortical activation patterns by functional MRI in a patient who received bilateral hand transplantation after amputation 6 years ago and in a patient who had received unilateral hand replantation within 2 hours after amputation. In the early postoperative period, the patient who had had the hand transplantation revealed strong activation of a higher motor area, only weak activation of the primary sensorimotor motor cortex and no activation of the primary somatosensory cortex. At 1-year follow-up, a small increase in primary sensorimotor motor cortex activation was observed. Activation of the primary somatosensory cortex was only seen at the 2 year follow-up. By contrast, after hand replantation, the activation pattern was similar to that of the uninjured hand within 6 weeks. This included activation of the primary sensorimotor motor cortex, higher motor areas and primary somatosensory cortex. Transplantation after long-standing amputation results in cortical reorganization occurring over a 2-year period. In contrast, hand replantation within a few hours preserves a normal activation pattern. PMID:16055246

  17. Motor-Skill Learning Is Dependent on Astrocytic Activity

    PubMed Central

    Padmashri, Ragunathan; Suresh, Anand; Boska, Michael D.; Dunaevsky, Anna

    2015-01-01

    Motor-skill learning induces changes in synaptic structure and function in the primary motor cortex through the involvement of a long-term potentiation- (LTP-) like mechanism. Although there is evidence that calcium-dependent release of gliotransmitters by astrocytes plays an important role in synaptic transmission and plasticity, the role of astrocytes in motor-skill learning is not known. To test the hypothesis that astrocytic activity is necessary for motor-skill learning, we perturbed astrocytic function using pharmacological and genetic approaches. We find that perturbation of astrocytes either by selectively attenuating IP3R2 mediated astrocyte Ca2+ signaling or using an astrocyte specific metabolic inhibitor fluorocitrate (FC) results in impaired motor-skill learning of a forelimb reaching-task in mice. Moreover, the learning impairment caused by blocking astrocytic activity using FC was rescued by administration of the gliotransmitter D-serine. The learning impairments are likely caused by impaired LTP as FC blocked LTP in slices and prevented motor-skill training-induced increases in synaptic AMPA-type glutamate receptor in vivo. These results support the conclusion that normal astrocytic Ca2+ signaling during a reaching task is necessary for motor-skill learning. PMID:26346977

  18. T Lymphocyte Activation Threshold and Membrane Reorganization Perturbations in Unique Culture Model

    NASA Technical Reports Server (NTRS)

    Adams, C. L.; Sams, C. F.

    2000-01-01

    Quantitative activation thresholds and cellular membrane reorganization are mechanisms by which resting T cells modulate their response to activating stimuli. Here we demonstrate perturbations of these cellular processes in a unique culture system that non-invasively inhibits T lymphocyte activation. During clinorotation, the T cell activation threshold is increased 5-fold. This increased threshold involves a mechanism independent of TCR triggering. Recruitment of lipid rafts to the activation site is impaired during clinorotation but does occur with increased stimulation. This study describes a situation in which an individual cell senses a change in its physical environment and alters its cell biological behavior.

  19. Social interaction is associated with changes in infants’ motor activity

    PubMed Central

    Scola, Céline; Bourjade, Marie; Jover, Marianne

    2015-01-01

    Background In developmental research, infants are commonly assumed to be early stakeholders in interactions with their caregivers. The tools that infants can use to interact with others vary from visual contact to smiling or vocalizing, and also include motor activity. However, surprisingly few studies have explored how the nature and context of social interactions affect infants’ engagement in motor activity. Methods We investigated the kinematic properties of foot and face movements produced by 11 infants aged between 5 and 9 months during six contrasting dyadic episodes (i.e. passive presence of a stranger or the infant's mother, weak or intense interaction with the stranger/mother as she sings a nursery play song). Results The infants’ face and foot motor activity was significantly reduced during the interactive episodes, compared with the episodes without any interaction, in both the mother and stranger conditions. Furthermore, the level of their motor activity was significantly lower in the stranger condition than in the mother one for some parameters. Conclusion These results are in line with those reported by previous studies and confirm the relevance of using motor activity to delineate the early forms of interactive episodes in infants. PMID:26546793

  20. Developmental changes in motor cortex activity as infants develop functional motor skills.

    PubMed

    Nishiyori, Ryota; Bisconti, Silvia; Meehan, Sean K; Ulrich, Beverly D

    2016-09-01

    Despite extensive research examining overt behavioral changes of motor skills in infants, the neural basis underlying the emergence of functional motor control has yet to be determined. We used functional near-infrared spectroscopy (fNIRS) to record hemodynamic activity of the primary motor cortex (M1) from 22 infants (11 six month-olds, 11 twelve month-olds) as they reached for an object, and stepped while supported over a treadmill. Based on the developmental systems framework, we hypothesized that as infants increased goal-directed experience, neural activity shifts from a diffused to focal pattern. Results showed that for reaching, younger infants showed diffuse areas of M1 activity that became focused by 12 months. For elicited stepping, younger infants produced much less M1 activity which shifted to diffuse activity by 12 months. Thus, the data suggest that as infants gain goal-directed experience, M1 activity emerges, initially showing a diffuse area of activity, becoming refined as the behavior stabilizes. Our data begin to document the cortical activity underlying early functional skill acquisition. PMID:27096281

  1. Active contractility and motor-driven effective interactions in a model cytoskeleton

    NASA Astrophysics Data System (ADS)

    Wang, Shenshen; Wolynes, Peter

    2013-03-01

    Contractile forces are essential for many developmental processes involving cell shape change and tissue deformation. Recent experiments on reconstituted actomyosin network, the major component of the contractile machinery, have shown that active contractility occurs above a threshold motor concentration and within a window of cross-link concentration. We present a microscopic dynamic model that incorporates two essential aspects of actomyosin self-organization: the asymmetric load response of individual actin filaments and the correlated motor-driven events mimicking myosin-induced filament sliding. Using computer simulations, we examine how the concentration and susceptibility of motors contribute to their collective behavior and interplay with the network connectivity to regulate macroscopic contractility. Our model is shown to capture the formation and dynamics of contractile structures and agree with the observed dependence of active contractility on microscopic parameters. We further provide a theoretical framework to investigate the intricate interplay between local force generation, network connectivity and collective action of molecular motors. This framework is capable of accommodating both regular and heterogeneous pattern formation, arrested coarsening and macroscopic contraction in a unified manner. This work is supported by NSF via Grant PHY-0822283 and the Bullard-Welch Chair at Rice University.

  2. Threshold bedrock channels in tectonically active mountains with frequent mass wasting

    NASA Astrophysics Data System (ADS)

    Korup, O.; Hayakawa, Y. S.; Codilean, A.; Oguchi, T.

    2013-12-01

    Models of how mountain belts grow and erode through time largely rely on the paradigm of fluvial bedrock incision as the main motor of response to differences in rock uplift, thus setting base levels of erosion in tectonically active landscapes. Dynamic feedbacks between rock uplift, bedrock river geometry, and mass wasting have been encapsulated within the concept of threshold hillslopes that attain a mechanically critical inclination capable of adjusting to fluvial incision rates via decreased stability and commensurately more frequent landsliding. Here we provide data that challenge the widely held view that channel steepness records tectonic forcing more faithfully than hillslope inclination despite much robust empirical evidence of such links between bedrock-river geometry and hillslope mass wasting. We show that the volume mobilized by mass wasting depends more on local topographic relief and the sinuosity of bedrock rivers than their mean normalized channel steepness. We derive this counterintuitive observation from an unprecedented inventory of ~300,000 landslides covering the tectonically active Japanese archipelago with substantial differences in seismicity, lithology, vertical surface deformation, topography, and precipitation variability. Both total landslide number and volumes increase nonlinearly with mean local relief even in areas where the fraction of steepest channel segments attains a constant threshold well below the maximum topographic relief. Our data document for the first time that mass wasting increases systematically with preferential steepening of flatter channel segments. Yet concomitant changes in mean channel steepness are negligible such that it remains a largely insensitive predictor of landslide denudation. Further, minute increases in bedrock-river sinuosity lead to substantial reduction in landslide abundance and volumes. Our results underline that sinuosity (together with mean local relief) is a key morphometric variable for

  3. Activity-Focused Motor Interventions for Children with Neurological Conditions

    ERIC Educational Resources Information Center

    Valvano, Joanne

    2004-01-01

    This article presents a model to guide activity-focused physical therapy and occupational therapy interventions for children with neurological conditions. Activity-focused interventions involve structured practice and repetition of functional actions and are directed toward the learning of motor tasks that will increase independence and…

  4. Mushroom bodies enhance initial motor activity in Drosophila.

    PubMed

    Serway, Christine N; Kaufman, Rebecca R; Strauss, Roland; de Belle, J Steven

    2009-01-01

    The central body (or central complex, CCX) and the mushroom bodies (MBs) are brain structures in most insect phyla that have been shown to influence aspects of locomotion. The CCX regulates motor coordination and enhances activity while MBs have, thus far, been shown to suppress motor activity levels measured over time intervals ranging from hours to weeks. In this report, we investigate MB involvement in motor behavior during the initial stages (15 minutes) of walking in Buridan's paradigm. We measured aspects of walking in flies that had MB lesions induced by mutations in six different genes and by chemical ablation. All tested flies were later examined histologically to assess MB neuroanatomy. Mutant strains with MB structural defects were generally less active in walking than wild-type flies. Most mutants in which MBs were also ablated with hydroxyurea (HU) showed additional activity decrements. Variation in measures of velocity and orientation to landmarks among wild-type and mutant flies was attributed to pleiotropy, rather than to MB lesions. We conclude that MBs upregulate activity during the initial stages of walking, but suppress activity thereafter. An MB influence on decision making has been shown in a wide range of complex behaviors. We suggest that MBs provide appropriate contextual information to motor output systems in the brain, indirectly fine tuning walking by modifying the quantity (i.e., activity) of behavior. PMID:19145515

  5. Automatic motor activation in the executive control of action

    PubMed Central

    McBride, Jennifer; Boy, Frédéric; Husain, Masud; Sumner, Petroc

    2012-01-01

    Although executive control and automatic behavior have often been considered separate and distinct processes, there is strong emerging and convergent evidence that they may in fact be intricately interlinked. In this review, we draw together evidence showing that visual stimuli cause automatic and unconscious motor activation, and how this in turn has implications for executive control. We discuss object affordances, alien limb syndrome, the visual grasp reflex, subliminal priming, and subliminal triggering of attentional orienting. Consideration of these findings suggests automatic motor activation might form an intrinsic part of all behavior, rather than being categorically different from voluntary actions. PMID:22536177

  6. Active, motor-driven mechanics in a DNA gel

    PubMed Central

    Bertrand, Olivier J. N.; Fygenson, Deborah Kuchnir; Saleh, Omar A.

    2012-01-01

    Cells are capable of a variety of dramatic stimuli-responsive mechanical behaviors. These capabilities are enabled by the pervading cytoskeletal network, an active gel composed of structural filaments (e.g., actin) that are acted upon by motor proteins (e.g., myosin). Here, we describe the synthesis and characterization of an active gel using noncytoskeletal components. We use methods of base-pair-templated DNA self assembly to create a hybrid DNA gel containing stiff tubes and flexible linkers. We then activate the gel by adding the motor FtsK50C, a construct derived from the bacterial protein FtsK that, in vitro, has a strong and processive DNA contraction activity. The motors stiffen the gel and create stochastic contractile events that affect the positions of attached beads. We quantify the fluctuations of the beads and show that they are comparable both to measurements of cytoskeletal systems and to theoretical predictions for active gels. Thus, we present a DNA-based active gel whose behavior highlights the universal aspects of nonequilibrium, motor-driven networks. PMID:23045635

  7. Reduced respiratory neural activity elicits phrenic motor facilitation.

    PubMed

    Mahamed, Safraaz; Strey, Kristi A; Mitchell, Gordon S; Baker-Herman, Tracy L

    2011-03-15

    We hypothesized that reduced respiratory neural activity elicits compensatory mechanisms of plasticity that enhance respiratory motor output. In urethane-anesthetized and ventilated rats, we reversibly reduced respiratory neural activity for 25-30 min using: hypocapnia (end tidal CO(2)=30 mmHg), isoflurane (~1%) or high frequency ventilation (HFV; ~100 breaths/min). In all cases, increased phrenic burst amplitude was observed following restoration of respiratory neural activity (hypocapnia: 92±22%; isoflurane: 65±22%; HFV: 54±13% baseline), which was significantly greater than time controls receiving the same surgery, but no interruptions in respiratory neural activity (3±5% baseline, p<0.05). Hypocapnia also elicited transient increases in respiratory burst frequency (9±2 versus 1±1bursts/min, p<0.05). Our results suggest that reduced respiratory neural activity elicits a unique form of plasticity in respiratory motor control which we refer to as inactivity-induced phrenic motor facilitation (iPMF). iPMF may prevent catastrophic decreases in respiratory motor output during ventilatory control disorders associated with abnormal respiratory activity. PMID:21167322

  8. Reduced respiratory neural activity elicits phrenic motor facilitation

    PubMed Central

    Mahamed, Safraaz; Strey, Kristi A.; Mitchell, Gordon S.; Baker-Herman, Tracy L.

    2011-01-01

    We hypothesized that reduced respiratory neural activity elicits compensatory mechanisms of plasticity that enhance respiratory motor output. In urethane-anesthetized and ventilated rats, we reversibly reduced respiratory neural activity for 25–30 min using: hypocapnia (end tidal CO2 = 30 mmHg), isoflurane (~ 1%) or high frequency ventilation (HFV; ~100 breaths/min). In all cases, increased phrenic burst amplitude was observed following restoration of respiratory neural activity (hypocapnia: 92 ± 22%; isoflurane: 65 ± 22%; HFV: 54 ± 13% baseline), which was significantly greater than time controls receiving the same surgery, but no interruptions in respiratory neural activity (3 ± 5% baseline, p<0.05). Hypocapnia also elicited transient increases in respiratory burst frequency (9 ± 2 versus 1 ± 1 bursts/min, p<0.05). Our results suggest that reduced respiratory neural activity elicits a unique form of plasticity in respiratory motor control which we refer to as inactivity-induced phrenic motor facilitation (iPMF). iPMF may prevent catastrophic decreases in respiratory motor output during ventilatory control disorders associated with abnormal respiratory activity. PMID:21167322

  9. THE ORIGIN OF SEGMENTATION MOTOR ACTIVITY IN THE INTESTINE

    PubMed Central

    Huizinga, Jan D.; Chen, Ji-Hong; Zhu, Yong Fang; Pawelka, Andrew; McGinn, Ryan J.; Bardakjian, Berj L.; Parsons, Sean P.; Kunze, Wolfgang A.; Wu, Richard You; Bercik, Premysl; Khoshdel, Amir; Chen, Sifeng; Yin, Sheng; Zhang, Qian; Yu, Yuanjie; Gao, Qingmin; Li, Kongling; Hu, Xinghai; Zarate, Natalia; Collins, Phillip; Pistilli, Marc; Ma, Junling; Zhang, Ruixue; Chen, David

    2016-01-01

    The segmentation motor activity of the gut that facilitates absorption of nutrients, was first described in the late 19th century but the fundamental mechanisms underlying it remain poorly understood. The dominant theory suggests alternate excitation and inhibition from the enteric nervous system. Here we demonstrate that typical segmentation can occur after total nerve blockade. The segmentation motor pattern emerges when the amplitude of the dominant pacemaker, the slow wave generated by ICC associated with the myenteric plexus (ICC-MP), is modulated by the phase of induced lower frequency rhythmic transient depolarizations, generated by ICC associated with the deep muscular plexus (ICC-DMP), resulting in a waxing and waning of the amplitude of the slow wave and a rhythmic checkered pattern of segmentation motor activity. Phase amplitude modulation of the slow waves points to an underlying system of coupled nonlinear oscillators originating in ICC. PMID:24561718

  10. Abstract art and cortical motor activation: an EEG study

    PubMed Central

    Umilta', M. Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works. PMID:23162456

  11. Neck motor unit activities induced by inputs from periodontal mechanoreceptors in rats.

    PubMed

    Zeredo, J L; Toda, K; Soma, K

    2002-01-01

    Clinical evidence suggests that head movements may be coupled with oro-facial functions, which are predominantly controlled by somatosensory inputs from the oro-facial area. However, the effects of specific modalities of sensory inputs on the neck muscles' motor activity are still unclear. In the present study, natural pressure stimulation was applied to the rat's upper first molars, while motor unit electromyographic activity was recorded from the dorsal neck splenius muscle. During the hold phase of pressure stimulation, clear tonic discharges were elicited in the splenius muscles on both sides. Mean threshold values were 622.3 mN (+/- 19.6 SEM, n = 39) and 496.8 mN (+/- 26.4 SEM, n = 43) for ipsi- and contralateral sides, respectively (p < 0.001, Mann-Whitney U test). Analysis of our data suggests that periodontal inputs may play an important role in controlling the motor activity of neck muscles, in addition to its well-known coordination of the masticatory function. PMID:11820365

  12. Recreational Activities and Motor Skills of Children in Kindergarten

    ERIC Educational Resources Information Center

    Temple, Viviene A.; Crane, Jeff R.; Brown, Amy; Williams, Buffy-Lynne; Bell, Rick I.

    2016-01-01

    Background: Developmental theorists suggest that physical activity during early childhood promotes fundamental motor skill (FMS) proficiency; and that differences in FMS proficiency are largely related to children's experiences. Aim: To examine associations between participation in different types of recreation/leisure and FMS proficiency of boys…

  13. Sport and Other Motor Activities of Warsaw Students

    ERIC Educational Resources Information Center

    Biernat, Elzbieta

    2011-01-01

    Study aim: To assess the engagement of students of Warsaw university schools in sports and in recreational motor activities. Material and methods: A cohort (n = 1100) of students attending B.S. or M.S. courses at 6 university schools in Warsaw were studied by applying questionnaire techniques. The questions pertained to participation in…

  14. Brains and Brawn: Complex Motor Activities to Maximize Cognitive Enhancement

    ERIC Educational Resources Information Center

    Moreau, David

    2015-01-01

    The target articles in this special issue address the timely question of embodied cognition in the classroom, and in particular the potential of this approach to facilitate learning in children. The interest for motor activities within settings that typically give little space to nontraditional content is proof of a shift from a Cartesian…

  15. Face Preference in Infancy and Its Relation to Motor Activity

    ERIC Educational Resources Information Center

    Libertus, Klaus; Needham, Amy

    2014-01-01

    Infants' preference for faces was investigated in a cross-sectional sample of 75 children, aged 3 to 11 months, and 23 adults. A visual preference paradigm was used where pairs of faces and toys were presented side-by-side while eye gaze was recorded. In addition, motor activity was assessed via parent report and the relation between motor…

  16. 40 CFR 798.6200 - Motor activity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... addition to the reporting requirements specified under 40 CFR part 792, subpart J the final test report... activity,” Handbook of Psychopharmacology. Vol. 7. Eds. Iversen, L.L., Iversen, D.S., Snyder, S.H....

  17. 40 CFR 798.6200 - Motor activity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... addition to the reporting requirements specified under 40 CFR part 792, subpart J the final test report... activity,” Handbook of Psychopharmacology. Vol. 7. Eds. Iversen, L.L., Iversen, D.S., Snyder, S.H....

  18. 40 CFR 798.6200 - Motor activity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... addition to the reporting requirements specified under 40 CFR part 792, subpart J the final test report... activity,” Handbook of Psychopharmacology. Vol. 7. Eds. Iversen, L.L., Iversen, D.S., Snyder, S.H....

  19. 40 CFR 798.6200 - Motor activity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... addition to the reporting requirements specified under 40 CFR part 792, subpart J the final test report... activity,” Handbook of Psychopharmacology. Vol. 7. Eds. Iversen, L.L., Iversen, D.S., Snyder, S.H....

  20. 40 CFR 798.6200 - Motor activity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... addition to the reporting requirements specified under 40 CFR part 792, subpart J the final test report... activity,” Handbook of Psychopharmacology. Vol. 7. Eds. Iversen, L.L., Iversen, D.S., Snyder, S.H....

  1. Motor unit activity during different functional states of the neuromuscular system.

    PubMed

    Gantchev, G N; Gatev, P; Ivanova, T; Tankov, N

    1986-01-01

    The study showed that the mean interspike interval (ISI) and the variability of ISIs increased with fatigue for both low and high threshold motor units (MUs). The recruitment threshold tension decreased for both the low and high threshold MUs while the recruitment threshold in % of maximal voluntary contraction changed selectively because of decrease of muscle force. During ischaemia after an initial decrease of mean ISI and ISIs' variability there was an essential increase of variability of ISIs at almost the same mean ISI followed by a considerable final increase of both parameters. MUs' recruitment thresholds lowered with ischaemia more rapidly in the beginning and especially in the final stage of ischaemia. PMID:3964248

  2. Dreaming: Cognitive Processes during Cortical Activation and High Afferent Thresholds.

    ERIC Educational Resources Information Center

    Antrobus, John

    1991-01-01

    Current theories and research on distributed activation in sleep are reviewed, and a neurocognitive theory of sleep is presented that is based on distributed activation. Neural and cognitive relationships described by the theory are translated into connectionist models, and simulations are described. (SLD)

  3. 3D visualization of movements can amplify motor cortex activation during subsequent motor imagery.

    PubMed

    Sollfrank, Teresa; Hart, Daniel; Goodsell, Rachel; Foster, Jonathan; Tan, Tele

    2015-01-01

    A repetitive movement practice by motor imagery (MI) can influence motor cortical excitability in the electroencephalogram (EEG). This study investigated if a realistic visualization in 3D of upper and lower limb movements can amplify motor related potentials during subsequent MI. We hypothesized that a richer sensory visualization might be more effective during instrumental conditioning, resulting in a more pronounced event related desynchronization (ERD) of the upper alpha band (10-12 Hz) over the sensorimotor cortices thereby potentially improving MI based brain-computer interface (BCI) protocols for motor rehabilitation. The results show a strong increase of the characteristic patterns of ERD of the upper alpha band components for left and right limb MI present over the sensorimotor areas in both visualization conditions. Overall, significant differences were observed as a function of visualization modality (VM; 2D vs. 3D). The largest upper alpha band power decrease was obtained during MI after a 3-dimensional visualization. In total in 12 out of 20 tasks the end-user of the 3D visualization group showed an enhanced upper alpha ERD relative to 2D VM group, with statistical significance in nine tasks.With a realistic visualization of the limb movements, we tried to increase motor cortex activation during subsequent MI. The feedback and the feedback environment should be inherently motivating and relevant for the learner and should have an appeal of novelty, real-world relevance or aesthetic value (Ryan and Deci, 2000; Merrill, 2007). Realistic visual feedback, consistent with the participant's MI, might be helpful for accomplishing successful MI and the use of such feedback may assist in making BCI a more natural interface for MI based BCI rehabilitation. PMID:26347642

  4. 3D visualization of movements can amplify motor cortex activation during subsequent motor imagery

    PubMed Central

    Sollfrank, Teresa; Hart, Daniel; Goodsell, Rachel; Foster, Jonathan; Tan, Tele

    2015-01-01

    A repetitive movement practice by motor imagery (MI) can influence motor cortical excitability in the electroencephalogram (EEG). This study investigated if a realistic visualization in 3D of upper and lower limb movements can amplify motor related potentials during subsequent MI. We hypothesized that a richer sensory visualization might be more effective during instrumental conditioning, resulting in a more pronounced event related desynchronization (ERD) of the upper alpha band (10–12 Hz) over the sensorimotor cortices thereby potentially improving MI based brain-computer interface (BCI) protocols for motor rehabilitation. The results show a strong increase of the characteristic patterns of ERD of the upper alpha band components for left and right limb MI present over the sensorimotor areas in both visualization conditions. Overall, significant differences were observed as a function of visualization modality (VM; 2D vs. 3D). The largest upper alpha band power decrease was obtained during MI after a 3-dimensional visualization. In total in 12 out of 20 tasks the end-user of the 3D visualization group showed an enhanced upper alpha ERD relative to 2D VM group, with statistical significance in nine tasks.With a realistic visualization of the limb movements, we tried to increase motor cortex activation during subsequent MI. The feedback and the feedback environment should be inherently motivating and relevant for the learner and should have an appeal of novelty, real-world relevance or aesthetic value (Ryan and Deci, 2000; Merrill, 2007). Realistic visual feedback, consistent with the participant’s MI, might be helpful for accomplishing successful MI and the use of such feedback may assist in making BCI a more natural interface for MI based BCI rehabilitation. PMID:26347642

  5. Hyperactivity and Motoric Activity in ADHD: Characterization, Assessment, and Intervention.

    PubMed

    Gawrilow, Caterina; Kühnhausen, Jan; Schmid, Johanna; Stadler, Gertraud

    2014-01-01

    The aim of the present literature review is threefold. (1) We will review theories, models, and studies on symptomatic hyperactivity and motoric activity in attention-deficit/hyperactivity disorder (ADHD). (2) Another focus will be on assessment methods that have been proven to be effective in the detection of hyperactivity and motoric activity in children, adolescents, and adults with and without ADHD and emerging areas of research in the field of ADHD. We will compare subjective methods (i.e., rating scales) and objective methods (i.e., accelerometers). (3) Finally, physical activity intervention studies aiming at a modification of activity and overactive behavior will be summarized that seem to be promising candidates for alleviating hyperactivity symptoms in children, adolescents, and adults with ADHD. PMID:25506329

  6. Hyperactivity and Motoric Activity in ADHD: Characterization, Assessment, and Intervention

    PubMed Central

    Gawrilow, Caterina; Kühnhausen, Jan; Schmid, Johanna; Stadler, Gertraud

    2014-01-01

    The aim of the present literature review is threefold. (1) We will review theories, models, and studies on symptomatic hyperactivity and motoric activity in attention-deficit/hyperactivity disorder (ADHD). (2) Another focus will be on assessment methods that have been proven to be effective in the detection of hyperactivity and motoric activity in children, adolescents, and adults with and without ADHD and emerging areas of research in the field of ADHD. We will compare subjective methods (i.e., rating scales) and objective methods (i.e., accelerometers). (3) Finally, physical activity intervention studies aiming at a modification of activity and overactive behavior will be summarized that seem to be promising candidates for alleviating hyperactivity symptoms in children, adolescents, and adults with ADHD. PMID:25506329

  7. Subcortical evoked activity and motor enhancement in Parkinson's disease

    PubMed Central

    Anzak, Anam; Tan, Huiling; Pogosyan, Alek; Khan, Sadaquate; Javed, Shazia; Gill, Steven S.; Ashkan, Keyoumars; Akram, Harith; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Green, Alexander L.; Aziz, Tipu; Brown, Peter

    2016-01-01

    Enhancements in motor performance have been demonstrated in response to intense stimuli both in healthy subjects and in the form of ‘paradoxical kinesis’ in patients with Parkinson's disease. Here we identify a mid-latency evoked potential in local field potential recordings from the region of the subthalamic nucleus, which scales in amplitude with both the intensity of the stimulus delivered and corresponding enhancements in biomechanical measures of maximal handgrips, independent of the dopaminergic state of our subjects with Parkinson's disease. Recordings of a similar evoked potential in the related pedunculopontine nucleus – a key component of the reticular activating system – provide support for this neural signature in the subthalmic nucleus being a novel correlate of ascending arousal, propagated from the reticular activating system to exert an ‘energizing’ influence on motor circuitry. Future manipulation of this system linking arousal and motor performance may provide a novel approach for the non-dopaminergic enhancement of motor performance in patients with hypokinetic disorders such as Parkinson's disease. PMID:26687971

  8. Subcortical evoked activity and motor enhancement in Parkinson's disease.

    PubMed

    Anzak, Anam; Tan, Huiling; Pogosyan, Alek; Khan, Sadaquate; Javed, Shazia; Gill, Steven S; Ashkan, Keyoumars; Akram, Harith; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Green, Alexander L; Aziz, Tipu; Brown, Peter

    2016-03-01

    Enhancements in motor performance have been demonstrated in response to intense stimuli both in healthy subjects and in the form of 'paradoxical kinesis' in patients with Parkinson's disease. Here we identify a mid-latency evoked potential in local field potential recordings from the region of the subthalamic nucleus, which scales in amplitude with both the intensity of the stimulus delivered and corresponding enhancements in biomechanical measures of maximal handgrips, independent of the dopaminergic state of our subjects with Parkinson's disease. Recordings of a similar evoked potential in the related pedunculopontine nucleus - a key component of the reticular activating system - provide support for this neural signature in the subthalmic nucleus being a novel correlate of ascending arousal, propagated from the reticular activating system to exert an 'energizing' influence on motor circuitry. Future manipulation of this system linking arousal and motor performance may provide a novel approach for the non-dopaminergic enhancement of motor performance in patients with hypokinetic disorders such as Parkinson's disease. PMID:26687971

  9. Relationship between stretch reflex thresholds and voluntary arm muscle activation in patients with spasticity.

    PubMed

    Musampa, Nadine K; Mathieu, Pierre A; Levin, Mindy F

    2007-08-01

    Previous studies have shown that deficits in agonist-antagonist muscle activation in the single-joint elbow system in patients with spastic hemiparesis are directly related to limitations in the range of regulation of the thresholds of muscle activation. We extended these findings to the double-joint, shoulder-elbow system in these patients. Ten non-disabled individuals and 11 stroke survivors with spasticity in upper limb muscles participated. Stroke survivors had sustained a single unilateral stroke 6-36 months previously, had full pain-free passive range of motion of the affected shoulder and elbow and had some voluntary control of the arm. EMG activity from four elbow and two shoulder muscles was recorded during quasi-static (<5 degrees /s) stretching of elbow flexors/extensors and during slow voluntary elbow flexion/extension movement through full range. Stretches and active movements were initiated from full elbow flexion or extension with the shoulder in three different initial positions (60 degrees , 90 degrees , 145 degrees horizontal abduction). SRTs were defined as the elbow angle at which EMG signals began to exceed 2SD of background noise. SRT angles obtained by passive muscle stretch were compared with the angles at which the respective muscles became activated during voluntary elbow movements. SRTs in elbow flexors were correlated with clinical spasticity scores. SRTs of elbow flexors and extensors were within the biomechanical range of the joint and varied with changes in the shoulder angle in all subjects with hemiparesis but could not be reached in this range in all healthy subjects when muscles were initially relaxed. In patients, limitations in the regulation of SRTs resulted in a subdivision of all-possible shoulder-elbow arm configurations into two areas, one in which spasticity was present ("spatial spasticity zone") and another in which it was absent. Spatial spasticity zones were different for different muscles in different patients but

  10. T Lymphocyte Activation Threshold is Increased in Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Adams, Charley L.; Gonzalez, M.; Sams, C. F.

    2000-01-01

    There have been substantial advances in molecular and cellular biology that have provided new insight into the biochemical and genetic basis of lymphocyte recognition, activation and expression of distinct functional phenotypes. It has now become evident that for both T and B cells, stimuli delivered through their receptors can result in either clonal expansion or apoptosis. In the case of T cells, clonal expansion of helper cells is accompanied by differentiation into two major functional subsets which regulate the immune response. The pathways between the membrane and the nucleus and their molecular components are an area of very active investigation. This meeting will draw together scientists working on diverse aspects of this problem, including receptor ligand interactions, intracellular pathways that transmit receptor mediated signals and the effect of such signal transduction pathways on gene regulation. The aim of this meeting is to integrate the information from these various experimental approaches into a new synthesis and molecular explanation of T cell activation, differentiation and death.

  11. Ice nucleus activity measurements of solid rocket motor exhaust particles

    NASA Technical Reports Server (NTRS)

    Keller, V. W. (Compiler)

    1986-01-01

    The ice Nucleus activity of exhaust particles generated from combustion of Space Shuttle propellant in small rocket motors has been measured. The activity at -20 C was substantially lower than that of aerosols generated by unpressurized combustion of propellant samples in previous studies. The activity decays rapidly with time and is decreased further in the presence of moist air. These tests corroborate the low effectivity ice nucleus measurement results obtained in the exhaust ground cloud of the Space Shuttle. Such low ice nucleus activity implies that Space Shuttle induced inadvertent weather modification via an ice phase process is extremely unlikely.

  12. Ankle Accelerometry for Assessing Physical Activity among Adolescent Girls: Threshold Determination, Validity, Reliability, and Feasibility

    PubMed Central

    Hager, Erin R.; Treuth, Margarita S.; Gormely, Candice; Epps, LaShawna; Snitker, Soren; Black, Maureen M.

    2016-01-01

    Purpose Ankle accelerometry allows for 24-hour data collection, improving data volume/integrity versus hip accelerometry. Using Actical ankle accelerometry, the purpose was to (a) develop sensitive/specific thresholds; (b) examine validity/reliability; (c) compare new thresholds with manufacturer’s; and (d) examine feasibility in a community sample (low-income, urban adolescent girls). Methods Two studies were conducted with 6th–7th grade girls (age 10–14 years): Laboratory study (n=24)- Two Actical accelerometers were placed on the ankle and worn while measuring energy expenditure (Cosmed K4b2, Metabolic Equivalents (METs)) during 10 prescribed activities. Analyses included device equivalence reliability (intraclass correlation (ICC): activity counts of 2 Acticals), criterion-related validity (correlation: activity counts and METs), and calculations of sensitivity, specificity, kappa and ROC curves for thresholds. Free-Living study (n=459)- an Actical was worn >7 days on the ankle (full 24-hour days retained). Analyses included feasibility (frequencies: missing data) and paired t-tests (new thresholds versus manufacturer’s). Results Laboratory study- Actical demonstrated reliability (ICC=.92) and validity (r=.81). Thresholds demonstrated sensitivity (91%), specificity (84%), kappa=.73 (p=.043), area under curve range .81–.97. Free-Living study- 99.6% wore the accelerometer; 84.1% had complete/valid data (mean=5.7 days). Primary reasons for missing/invalid data: Improper programming/documentation (5.2%), failure to return device (5.0%), wear-time ≤2 days (2.8%). The Moderate to Vigorous Physical Activity (MVPA) threshold (>3200 counts/minute) yielded 37.2 minutes/day, 2–4.5 times lower than the manufacturer’s software (effect size=.74–4.05). Conclusions Validity, reliability, and feasibility evidences support Actical ankle accelerometry to assess physical activity in community studies of adolescent girls. When comparing manufacturers’ software

  13. Chemical and thermal modulation of molecular motor activities

    NASA Astrophysics Data System (ADS)

    Hong, Weili

    Molecular motors of kinesin and dynein families are responsible for various intracellular activities, from long distance movement of organelles, vesicles, protein complexes, and mRNAs to powering mitotic processes. They can take nanometer steps using chemical energy from the hydrolysis of ATP (adenosine triphosphate), and their dysfunction is involved in many neurodegenerative diseases that require long distance transport of cargos. Here I report on the study of the properties of molecular motors at a single-molecule level using optical trappings. I first studied the inhibition properties of kinesin motors by marine natural compound adociasulfates. I showed that adociasulfates compete with microtubules for binding to kinesins and thus inhibit kinesins' activity. Although adociasulfates are a strong inhibitor for all kinesin members, they show a much higher inhibition effect for conventional kinesins than for mitotic kinesins. Thus adociasulfates can be used to specifically inhibit conventional kinesins. By comparing the inhibition of kinesins by two structurally similar adociasulfates, one can see that the negatively charged sulfate residue of adociasulfates can be replaced by other negative residues and thus make it possible for adociasulfate-derived compounds to be more cell permeable. Kinesins and dyneins move cargos towards opposite directions along a microtubule. Cargos with both kinesins and dyneins attached often move bidirectionally due to undergoing a tug-of-war between the oppositely moving kinesin and dynein motors. Here I studied the effect of temperature on microtubule-based kinesin and dynein motor transport. While kinesins' and dyneins' velocities are closely matched above 15 °C, below this temperature the dyneins' velocity decreases much faster than the kinesins'. The kinesins' and dyneins' forces do not measurably change with temperature. The results suggest that temperature has significant effects on bidirectional transport and can be used to

  14. Diode laser threshold current density and lasing wavelength as functions of active region thickness

    SciTech Connect

    Streifer, W.; Scifres, D.R.; Burnham, R.D.

    1983-03-01

    Based on a simple model of the band-to-band absorption of a diode laser active region, we formulatean expression for modal gain as a function of pumping current. Using this result yields expressions for threshold current density and lasing photon energy which depend on device parameters including active region thickness, laser length, internal losses, facet reflectivity, etc.

  15. Motor activity following the silent period in human muscle

    PubMed Central

    Alston, W.; Angel, R. W.; Fink, F. S.; Hofmann, W. W.

    1967-01-01

    1. When a muscle is unloaded during voluntary contraction, there is normally a silent period in the electromyogram. The silence is terminated by a sudden return of muscle action potentials. 2. In order to investigate the mechanism of the terminal motor volley, the unloading reflex was studied in six human subjects. The independent variables were the initial muscular force, the inertia of the limb and the amount of motion permitted. The dependent variables were the size and latency of the terminal volley. 3. During isometric contraction, the amplitude of the surface-recorded muscle action potentials increased monotonically with increasing muscular tension. 4. The action potentials were significantly larger during the terminal volley than during the period before unloading. 5. When acceleration of the limb was reduced by increasing the inertia, the terminal volley was decreased in size, but the latency was not affected. 6. When movement was interrupted by a mechanical block, the latency of the terminal volley was reduced, but the size was not affected. 7. The results suggest that the terminal motor volley is not the result of a decrease in Renshaw feed-back or in autogenetic inhibition. 8. The motor volley must be regulated by proprioceptive feed-back, because it is affected by the velocity and displacement of the limb. 9. The muscle frequently responded within 20 msec after motion of the limb was blocked. Hence it appears that the mechanism involves a spinal reflex. 10. Because the motor discharge occurs while the muscle is shortening, it cannot be an ordinary stretch reflex. If the discharge is attributed to spindle afferent driving, one must assume that the gamma motor neurones are active during the silent period. 11. The authors postulate a fusimotor reflex, which is driven by afferent impulses from the moving limb and excites the alpha motoneurones by way of the `gamma loop'. PMID:6038019

  16. Radioactive sealed sources: Reasonable accountability, exemption, and licensing activity thresholds -- A technical basis

    SciTech Connect

    Lee, D.W.; Shingleton, K.L.

    1996-07-01

    Perhaps owing to their small size and portability, some radiation accidents/incidents have involved radioactive sealed sources (RSSs). As a result, programs for the control and accountability of RSSs have come to be recommended and emplaced that essentially require RSSs to be controlled in a manner different from bulk, unsealed radioactive material. Crucially determining the total number of RSSs for which manpower-intensive radiation protection surveillance is provided is the individual RSS activity above which such surveillance is required and below which such effort is not considered cost effective. Individual RSS activity thresholds are typically determined through scenarios which impart a chosen internal or external limiting dose to Reference Man under specified exposure conditions. The resultant RSS threshold activity levels have meaning commensurate with the assumed scenario exposure parameters, i.e., if they are realistic and technically based. A review of how the Department of Energy (DOE), the International Atomic Energy Agency (IAEA), and the Nuclear Regulatory Commission (NRC) have determined their respective accountability, exemption, and licensing threshold activity values is provided. Finally, a fully explained method using references readily available to practicing health physicists is developed using realistic, technically-based calculation parameters by which RSS threshold activities may be locally generated.

  17. Complex Dynamic Thresholds and Generation of the Action Potentials in the Neural-Activity Model

    NASA Astrophysics Data System (ADS)

    Kirillov, S. Yu.; Nekorkin, V. I.

    2016-05-01

    This work is devoted to studying the processes of activation of the neurons whose excitation thresholds are not constant and vary in time (the so-called dynamic thresholds). The neuron dynamics is described by the FitzHugh-Nagumo model with nonlinear behavior of the recovery variable. The neuron response to the external pulsed activating action in the presence of a slowly varying synaptic current is studied within the framework of this model. The structure of the dynamic threshold is studied and its properties depending on the external-action parameters are established. It is found that the formation of the "folds" in the separatrix threshold manifold in the model phase space is a typical feature of the complex dynamic threshold. High neuron sensitivity to the action of the comparatively weak slow control signals is established. This explains the capability of the neurons to perform flexible tuning of their selective properties for detecting various external signals in sufficiently short times (of the order of duration of several spikes).

  18. Complex Dynamic Thresholds and Generation of the Action Potentials in the Neural-Activity Model

    NASA Astrophysics Data System (ADS)

    Kirillov, S. Yu.; Nekorkin, V. I.

    2016-06-01

    This work is devoted to studying the processes of activation of the neurons whose excitation thresholds are not constant and vary in time (the so-called dynamic thresholds). The neuron dynamics is described by the FitzHugh-Nagumo model with nonlinear behavior of the recovery variable. The neuron response to the external pulsed activating action in the presence of a slowly varying synaptic current is studied within the framework of this model. The structure of the dynamic threshold is studied and its properties depending on the external-action parameters are established. It is found that the formation of the "folds" in the separatrix threshold manifold in the model phase space is a typical feature of the complex dynamic threshold. High neuron sensitivity to the action of the comparatively weak slow control signals is established. This explains the capability of the neurons to perform flexible tuning of their selective properties for detecting various external signals in sufficiently short times (of the order of duration of several spikes).

  19. Chronic Assessment of Diaphragm Muscle EMG Activity across Motor Behaviors

    PubMed Central

    Mantilla, Carlos B.; Seven, Yasin B.; Hurtado-Palomino, Juan N.; Zhan, Wen-Zhi; Sieck, Gary C.

    2011-01-01

    The diaphragm muscle is main inspiratory muscle in mammals. Quantitative analyses documenting the reliability of chronic diaphragm EMG recordings are lacking. Assessment of ventilatory and non-ventilatory motor behaviors may facilitate evaluating diaphragm EMG activity over time. We hypothesized that normalization of diaphragm EMG amplitude across behaviors provides stable and reliable parameters for longitudinal assessments of diaphragm activity. We found that diaphragm EMG activity shows substantial intra-animal variability over 6 weeks, with coefficient of variation (CV) for different behaviors ~29–42%. Normalization of diaphragm EMG activity to near maximal behaviors (e.g., deep breathing) reduced intra-animal variability over time (CV ~22–29%). Plethysmographic measurements of eupneic ventilation were also stable over 6 weeks (CV ~13% for minute ventilation). Thus, stable and reliable measurements of diaphragm EMG activity can be obtained longitudinally using chronically implanted electrodes by examining multiple motor behaviors. By quantitatively determining the reliability of longitudinal diaphragm EMG analyses, we provide an important tool for evaluating the progression of diseases or injuries that impair ventilation. PMID:21414423

  20. Motor Cortex Microcircuit Simulation Based on Brain Activity Mapping

    PubMed Central

    Chadderdon, George L.; Mohan, Ashutosh; Suter, Benjamin A.; Neymotin, Samuel A.; Kerr, Cliff C.; Francis, Joseph T.; Shepherd, Gordon M. G.; Lytton, William W.

    2016-01-01

    The deceptively simple laminar structure of neocortex belies the complexity of intra- and interlaminar connectivity. We developed a computational model based primarily on a unified set of brain activity mapping studies of mouse M1. The simulation consisted of 775 spiking neurons of 10 cell types with detailed population-to-population connectivity. Static analysis of connectivity with graph-theoretic tools revealed that the corticostriatal population showed strong centrality, suggesting that would provide a network hub. Subsequent dynamical analysis confirmed this observation, in addition to revealing network dynamics that cannot be readily predicted through analysis of the wiring diagram alone. Activation thresholds depended on the stimulated layer. Low stimulation produced transient activation, while stronger activation produced sustained oscillations where the threshold for sustained responses varied by layer: 13% in layer 2/3, 54% in layer 5A, 25% in layer 5B, and 17% in layer 6. The frequency and phase of the resulting oscillation also depended on stimulation layer. By demonstrating the effectiveness of combined static and dynamic analysis, our results show how static brain maps can be related to the results of brain activity mapping. PMID:24708371

  1. New Validated Thresholds for Various Intensities of Physical Activity in Adolescents Using the Actigraph Accelerometer

    ERIC Educational Resources Information Center

    Vanhelst, Jeremy; Beghin, Laurent; Turck, Dominique; Gottrand, Frederic

    2011-01-01

    The aim of this study was to determine and validate the new thresholds for various intensities of physical activity in adolescents using the Actigraph accelerometer. Sixty healthy participants aged 10-16 years were recruited. Forty participants participated in the calibration study whereas the others participated in the validation study.…

  2. Active Fault Tolerant Control for Ultrasonic Piezoelectric Motor

    NASA Astrophysics Data System (ADS)

    Boukhnifer, Moussa

    2012-07-01

    Ultrasonic piezoelectric motor technology is an important system component in integrated mechatronics devices working on extreme operating conditions. Due to these constraints, robustness and performance of the control interfaces should be taken into account in the motor design. In this paper, we apply a new architecture for a fault tolerant control using Youla parameterization for an ultrasonic piezoelectric motor. The distinguished feature of proposed controller architecture is that it shows structurally how the controller design for performance and robustness may be done separately which has the potential to overcome the conflict between performance and robustness in the traditional feedback framework. A fault tolerant control architecture includes two parts: one part for performance and the other part for robustness. The controller design works in such a way that the feedback control system will be solely controlled by the proportional plus double-integral PI2 performance controller for a nominal model without disturbances and H∞ robustification controller will only be activated in the presence of the uncertainties or an external disturbances. The simulation results demonstrate the effectiveness of the proposed fault tolerant control architecture.

  3. Intestinal motor activity in experimental hyperthyroidism in conscious dogs.

    PubMed

    Karaus, M; Wienbeck, M; Grussendorf, M; Erckenbrecht, J F; Strohmeyer, G

    1989-10-01

    The small intestinal motor effects of experimental hyperthyroidism were studied in 8 conscious dogs to reveal possible mechanisms of accelerated small bowel transit in hyperthyroidism. Six strain gauge transducers were implanted on the small intestine of each dog. Long-term hyperthyroidism was induced by subcutaneous administration of 100 and 200 micrograms/kg.day of thyroxin. Application of thyroxin did not interrupt the cyclic fasting motor activity. Thyroxin (100 micrograms/kg.day) caused a slight increase in the period of the migrating motor complex (p less than 0.05). The maximum contractile frequency rose dose-dependently up to 11% (p less than 0.05). During phase 2 and the digestive state the contraction frequency increased up to 29% and 27%, respectively (p less than 0.05). More contractions occurred in groups during the digestive state in hyperthyroidism. Half of the dogs showed giant migrating contractions during thyroxin administration, whereas those contractions were not observed during the control period. We conclude that fasted and postprandial intestinal motility is changed in experimental hyperthyroidism. Acceleration of small bowel transit may be caused by changes in contractile pattern of phase 2 and the digestive state or by the increased frequency of giant migrating contractions. PMID:2777044

  4. Neocerebellar control of the motor activity: experimental analysis in the rat. Comparative aspects.

    PubMed

    Cicirata, F; Angaut, P; Pantó, M R; Serapide, M F

    1989-01-01

    The results collected by electrical microstimulation of the nucleus lateralis of the cerebellum in anaesthetized rats may be summarized as follows. The stimulations evoked motor effects in head and forelimb principally whereas hindlimb was only occasionally involved. The movements were prevalently segregated to only one joint (simple movements), in a lesser degree they involved two or three segments (complex movements). Simple and complex movements were apparently distributed in the nuclear mass without topographical segregation or preferentiality. The electromyographic records suggest that the neocerebellar movements are of synergistic nature. A somatotopical organization was evidenced within the nucleus lateralis: 3 specific functional regions were identified in the caudorostral nuclear extension. They concern the forelimb (caudally), head (centrally) and hindlimb (rostrally). This somatotopical organization persisted unmodified following elimination of either the cerebral motor cortex alone or in addition to that of the red nucleus. The nuclear subdivisions of the cerebellar nucleus lateralis showed functional differences: (1) the dorsolateral hump of Goodman et al. was principally involved in lip movements; (2) the subnucleus lateralis parvocellularis elicited movements of single vibrissae, neck and medio-distal segments of the forelimb, prevalently; (3) the magnocellular subdivision essentially controlled both limbs with large prevalence for their medio-proximal segments. To identify the functional role of the different descending pathways which relay the neocerebellum to the cord, the motor effects evoked in intact rats were compared with those elicited in rats submitted to cortical ablation and/or to lesion of the red nucleus region. The integrity of the cerebral cortex was essential only for distalmost forelimb motor activities. After lesion of the rubral region (which concomitantly eliminates corticospinal output), the stimulation of the nucleus lateralis

  5. Time required for motor activity in lucid dreams.

    PubMed

    Erlacher, Daniel; Schredl, Michael

    2004-12-01

    The present study investigated the relationship between the time required for specific tasks (counting and performing squats) in lucid dreams and in the waking state. Five proficient lucid dreamers (26-34 yr. old, M=29.8, SD=3.0; one woman and four men) participated. Analysis showed that the time needed for counting in a lucid dream is comparable to the time needed for counting in wakefulness, but motor activities required more time in lucid dreams than in the waking state. PMID:15739850

  6. Decreased Activation of Subcortical Brain Areas in the Motor Fatigue State: An fMRI Study.

    PubMed

    Hou, Li J; Song, Zheng; Pan, Zhu J; Cheng, Jia L; Yu, Yong; Wang, Jun

    2016-01-01

    One aspect of motor fatigue is the exercise-induced reduction of neural activity to voluntarily drive the muscle or muscle group. Functional magnetic resonance imaging provides access to investigate the neural activation on the whole brain level and studies observed changes of activation intensity after exercise-induced motor fatigue in the sensorimotor cortex. However, in human, little evidence exists to demonstrate the role of subcortical brain regions in motor fatigue, which is contradict to abundant researches in rodent indicating that during simple movement, the activity of the basal ganglia is modulated by the state of motor fatigue. Thus, in present study, we explored the effect of motor fatigue on subcortical areas in human. A series of fMRI data were collected from 11 healthy subjects while they were executing simple motor tasks in two conditions: before and under the motor fatigue state. The results showed that in both conditions, movements evoked activation volumes in the sensorimotor areas, SMA, cerebellum, thalamus, and basal ganglia. Of primary importance are the results that the intensity and size of activation volumes in the subcortical areas (i.e., thalamus and basal ganglia areas) are significantly decreased during the motor fatigue state, implying that motor fatigue disturbs the motor control processing in a way that both sensorimotor areas and subcortical brain areas are less active. Further study is needed to clarify how subcortical areas contribute to the overall decreased activity of CNS during motor fatigue state. PMID:27536264

  7. Decreased Activation of Subcortical Brain Areas in the Motor Fatigue State: An fMRI Study

    PubMed Central

    Hou, Li J.; Song, Zheng; Pan, Zhu J.; Cheng, Jia L.; Yu, Yong; Wang, Jun

    2016-01-01

    One aspect of motor fatigue is the exercise-induced reduction of neural activity to voluntarily drive the muscle or muscle group. Functional magnetic resonance imaging provides access to investigate the neural activation on the whole brain level and studies observed changes of activation intensity after exercise-induced motor fatigue in the sensorimotor cortex. However, in human, little evidence exists to demonstrate the role of subcortical brain regions in motor fatigue, which is contradict to abundant researches in rodent indicating that during simple movement, the activity of the basal ganglia is modulated by the state of motor fatigue. Thus, in present study, we explored the effect of motor fatigue on subcortical areas in human. A series of fMRI data were collected from 11 healthy subjects while they were executing simple motor tasks in two conditions: before and under the motor fatigue state. The results showed that in both conditions, movements evoked activation volumes in the sensorimotor areas, SMA, cerebellum, thalamus, and basal ganglia. Of primary importance are the results that the intensity and size of activation volumes in the subcortical areas (i.e., thalamus and basal ganglia areas) are significantly decreased during the motor fatigue state, implying that motor fatigue disturbs the motor control processing in a way that both sensorimotor areas and subcortical brain areas are less active. Further study is needed to clarify how subcortical areas contribute to the overall decreased activity of CNS during motor fatigue state. PMID:27536264

  8. COCHLEAR IMPLANT ELECTRODE CONFIGURATION EFFECTS ON ACTIVATION THRESHOLD AND TONOTOPIC SELECTIVITY

    PubMed Central

    Snyder, Russell L.; Middlebrooks, John C.; Bonham, Ben H.

    2008-01-01

    The multichannel design of contemporary cochlear implants (CIs) is predicated on the assumption that each channel activates a relatively restricted and independent sector of the deaf auditory nerve array, just as a sound within a restricted frequency band activates a restricted region of the normal cochlea The independence of CI channels, however, is limited; and the factors that determine their independence, the relative overlap of the activity patterns that they evoke, are poorly understood. In this study, we evaluate the spread of activity evoked by cochlear implant channels by monitoring activity at 16 sites along the tonotopic axis of the guinea pig inferior colliculus (IC). “Spatial tuning curves” (STCs) measured in this way serve as an estimate of activation spread within the cochlea and the ascending auditory pathways. We contrast natural stimulation using acoustic tones with two kinds of electrical stimulation either (1) a loose fitting banded array consisting of a cylindrical silicone elastomer carrier with a linear series of ring contacts; or (2) a space-filling array consisting of a tapered silicone elastomer carrier that is designed to fit snugly into the guinea pig scala tympani with a linear series of ball contacts positioned along it Spatial tuning curves evoked by individual acoustic tones, and by activation of each contact of each array as a monopole, bipole or tripole were recorded. Several channel configurations and a wide range of electrode separations were tested for each array, and their thresholds and selectivity were estimated. The results indicate that the tapered space-filling arrays evoked more restricted activity patterns at lower thresholds than did the banded arrays. Monopolar stimulation (one intracochlear contact activated with an extracochlear return) using either array evoked broad activation patterns that involved the entire recording array at current levels < 6dB SL, but at relatively low thresholds. Bi- and tripolar

  9. Cochlear implant electrode configuration effects on activation threshold and tonotopic selectivity.

    PubMed

    Snyder, Russell L; Middlebrooks, John C; Bonham, Ben H

    2008-01-01

    The multichannel design of contemporary cochlear implants (CIs) is predicated on the assumption that each channel activates a relatively restricted and independent sector of the deaf auditory nerve array, just as a sound within a restricted frequency band activates a restricted region of the normal cochlea The independence of CI channels, however, is limited; and the factors that determine their independence, the relative overlap of the activity patterns that they evoke, are poorly understood. In this study, we evaluate the spread of activity evoked by cochlear implant channels by monitoring activity at 16 sites along the tonotopic axis of the guinea pig inferior colliculus (IC). "Spatial tuning curves" (STCs) measured in this way serve as an estimate of activation spread within the cochlea and the ascending auditory pathways. We contrast natural stimulation using acoustic tones with two kinds of electrical stimulation either (1) a loose fitting banded array consisting of a cylindrical silicone elastomer carrier with a linear series of ring contacts; or (2) a space-filling array consisting of a tapered silicone elastomer carrier that is designed to fit snugly into the guinea pig scala tympani with a linear series of ball contacts positioned along it Spatial tuning curves evoked by individual acoustic tones, and by activation of each contact of each array as a monopole, bipole or tripole were recorded. Several channel configurations and a wide range of electrode separations were tested for each array, and their thresholds and selectivity were estimated. The results indicate that the tapered space-filling arrays evoked more restricted activity patterns at lower thresholds than did the banded arrays. Monopolar stimulation (one intracochlear contact activated with an extracochlear return) using either array evoked broad activation patterns that involved the entire recording array at current levels <6dBSL, but at relatively low thresholds. Bi- and tri

  10. Plasma hyperosmolality elevates the internal temperature threshold for active thermoregulatory vasodilation during heat stress in humans.

    PubMed

    Shibasaki, Manabu; Aoki, Ken; Morimoto, Keiko; Johnson, John M; Takamata, Akira

    2009-12-01

    Plasma hyperosmolality delays the response in skin blood flow to heat stress by elevating the internal temperature threshold for cutaneous vasodilation. This elevation could be because of a delayed onset of cutaneous active vasodilation and/or to persistent cutaneous active vasoconstriction. Seven healthy men were infused with either hypertonic (3% NaCl) or isotonic (0.9% NaCl) saline and passively heated by immersing their lower legs in 42 degrees C water for 60 min (room temperature, 28 degrees C; relative humidity, 40%). Skin blood flow was monitored via laser-Doppler flowmetry at sites pretreated with bretylium tosylate (BT) to block sympathetic vasoconstriction selectively and at adjacent control sites. Plasma osmolality was increased by approximately 13 mosmol/kgH(2)O following hypertonic saline infusion and was unchanged following isotonic saline infusion. The esophageal temperature (T(es)) threshold for cutaneous vasodilation at untreated sites was significantly elevated in the hyperosmotic state (37.73 +/- 0.11 degrees C) relative to the isosmotic state (36.63 +/- 0.12 degrees C, P < 0.001). A similar elevation of the T(es) threshold for cutaneous vasodilation was observed between osmotic conditions at the BT-treated sites (37.74 +/- 0.18 vs. 36.67 +/- 0.07 degrees C, P < 0.001) as well as sweating. These results suggest that the hyperosmotically induced elevation of the internal temperature threshold for cutaneous vasodilation is due primarily to an elevation in the internal temperature threshold for the onset of active vasodilation, and not to an enhancement of vasoconstrictor activity. PMID:19812357

  11. Threshold responses of songbirds to long-term timber management on an active industrial forest

    USGS Publications Warehouse

    Becker, D.A.; Wood, P.B.; Keyser, P.D.; Wigley, T.B.; Dellinger, R.; Weakland, C.A.

    2011-01-01

    Forest managers often seek to balance economic benefits from timber harvesting with maintenance of habitat for wildlife, ecosystem function, and human uses. Most research on the relationship between avian abundance and active timber management has been short-term, lasting one to two years, creating the need to investigate long-term avian responses and to identify harvest thresholds when a small change in habitat results in a disproportionate response in relative abundance and nest success. Our objectives were to identify trends in relative abundance and nest success and to identify landscape-scale disturbance thresholds for avian species and habitat guilds in response to a variety of harvest treatments (clear-cuts, heavy and light partial harvests) over 14 years. We conducted point counts and monitored nests at an industrial forest in the central Appalachians of West Virginia during 1996-1998, 2001-2003, and 2007-2009. Early successional species increased in relative abundance across all three time periods, whereas interior-edge and forest-interior guilds peaked in relative abundance mid-study after which the forest-interior guild declined. Of 41 species with >10 detections, four (10%) declined significantly, 13 (32%) increased significantly (only three species among all periods), and 9 (22%) peaked in abundance mid-study (over the entire study period, four species had no significant change in abundance, four declined, and one increased). Based on piecewise linear models, forest-interior and interior-edge guilds' relative abundance harvest thresholds were 28% total harvests (all harvests combined), 10% clear-cut harvests, and 18% light partial harvests, after which abundances declined. Harvest thresholds for the early successional guild were 42% total harvests, 11% clear-cut harvest, and 10% light partial harvests, and relative abundances increased after surpassing thresholds albeit at a reduced rate of increase after the clear-cut threshold. Threshold confidence

  12. From Spontaneous Motor Activity to Coordinated Behaviour: A Developmental Model

    PubMed Central

    Marques, Hugo Gravato; Bharadwaj, Arjun; Iida, Fumiya

    2014-01-01

    In mammals, the developmental path that links the primary behaviours observed during foetal stages to the full fledged behaviours observed in adults is still beyond our understanding. Often theories of motor control try to deal with the process of incremental learning in an abstract and modular way without establishing any correspondence with the mammalian developmental stages. In this paper, we propose a computational model that links three distinct behaviours which appear at three different stages of development. In order of appearance, these behaviours are: spontaneous motor activity (SMA), reflexes, and coordinated behaviours, such as locomotion. The goal of our model is to address in silico four hypotheses that are currently hard to verify in vivo: First, the hypothesis that spinal reflex circuits can be self-organized from the sensor and motor activity induced by SMA. Second, the hypothesis that supraspinal systems can modulate reflex circuits to achieve coordinated behaviour. Third, the hypothesis that, since SMA is observed in an organism throughout its entire lifetime, it provides a mechanism suitable to maintain the reflex circuits aligned with the musculoskeletal system, and thus adapt to changes in body morphology. And fourth, the hypothesis that by changing the modulation of the reflex circuits over time, one can switch between different coordinated behaviours. Our model is tested in a simulated musculoskeletal leg actuated by six muscles arranged in a number of different ways. Hopping is used as a case study of coordinated behaviour. Our results show that reflex circuits can be self-organized from SMA, and that, once these circuits are in place, they can be modulated to achieve coordinated behaviour. In addition, our results show that our model can naturally adapt to different morphological changes and perform behavioural transitions. PMID:25057775

  13. Active Learning: Learning a Motor Skill Without a Coach

    PubMed Central

    Huang, Vincent S.; Shadmehr, Reza; Diedrichsen, Jörn

    2008-01-01

    When we learn a new skill (e.g., golf) without a coach, we are “active learners”: we have to choose the specific components of the task on which to train (e.g., iron, driver, putter, etc.). What guides our selection of the training sequence? How do choices that people make compare with choices made by machine learning algorithms that attempt to optimize performance? We asked subjects to learn the novel dynamics of a robotic tool while moving it in four directions. They were instructed to choose their practice directions to maximize their performance in subsequent tests. We found that their choices were strongly influenced by motor errors: subjects tended to immediately repeat an action if that action had produced a large error. This strategy was correlated with better performance on test trials. However, even when participants performed perfectly on a movement, they did not avoid repeating that movement. The probability of repeating an action did not drop below chance even when no errors were observed. This behavior led to suboptimal performance. It also violated a strong prediction of current machine learning algorithms, which solve the active learning problem by choosing a training sequence that will maximally reduce the learner's uncertainty about the task. While we show that these algorithms do not provide an adequate description of human behavior, our results suggest ways to improve human motor learning by helping people choose an optimal training sequence. PMID:18509079

  14. Active learning: learning a motor skill without a coach.

    PubMed

    Huang, Vincent S; Shadmehr, Reza; Diedrichsen, Jörn

    2008-08-01

    When we learn a new skill (e.g., golf) without a coach, we are "active learners": we have to choose the specific components of the task on which to train (e.g., iron, driver, putter, etc.). What guides our selection of the training sequence? How do choices that people make compare with choices made by machine learning algorithms that attempt to optimize performance? We asked subjects to learn the novel dynamics of a robotic tool while moving it in four directions. They were instructed to choose their practice directions to maximize their performance in subsequent tests. We found that their choices were strongly influenced by motor errors: subjects tended to immediately repeat an action if that action had produced a large error. This strategy was correlated with better performance on test trials. However, even when participants performed perfectly on a movement, they did not avoid repeating that movement. The probability of repeating an action did not drop below chance even when no errors were observed. This behavior led to suboptimal performance. It also violated a strong prediction of current machine learning algorithms, which solve the active learning problem by choosing a training sequence that will maximally reduce the learner's uncertainty about the task. While we show that these algorithms do not provide an adequate description of human behavior, our results suggest ways to improve human motor learning by helping people choose an optimal training sequence. PMID:18509079

  15. Physical activity, motor function, and white matter hyperintensity burden in healthy older adults

    PubMed Central

    Yang, Jingyun; Arfanakis, Konstantinos; Arvanitakis, Zoe; Leurgans, Sue E.; Turner, Arlener D.; Barnes, Lisa L.; Bennett, David A.; Buchman, Aron S.

    2015-01-01

    Objective: To test the hypothesis that physical activity modifies the association between white matter hyperintensity (WMH) burden and motor function in healthy older persons without dementia. Methods: Total daily activity (exercise and nonexercise physical activity) was measured for up to 11 days with actigraphy (Actical; Philips Respironics, Bend, OR) in 167 older adults without dementia participating in the Rush Memory and Aging Project. Eleven motor performances were summarized into a previously described global motor score. WMH volume was expressed as percent of intracranial volume. Linear regression models, adjusted for age, education, and sex, were performed with total WMH volume as the predictor and global motor score as the outcome. Terms for total daily physical activity and its interaction with WMH volume were then added to the model. Results: Higher WMH burden was associated with lower motor function (p = 0.006), and total daily activity was positively associated with motor function (p = 0.002). Total daily activity modified the association between WMH and motor function (p = 0.007). WMH burden was not associated with motor function in persons with high activity (90th percentile). By contrast, higher WMH burden remained associated with lower motor function in persons with average (50th percentile; estimate = −0.304, slope = −0.133) and low (10th percentile; estimate = −1.793, slope = −0.241) activity. Conclusions: Higher levels of physical activity may reduce the effect of WMH burden on motor function in healthy older adults. PMID:25762710

  16. Factors to consider when applying transcranial magnetic stimulation of dorsolateral prefrontal cortex when resting motor threshold is asymmetric: A case study.

    PubMed

    Maller, Jerome J; Thomson, Richard H S; McQueen, Susan; Elliot, David; Fitzgerald, Paul B

    2016-02-01

    Transcranial magnetic stimulation (TMS) is an increasingly popular tool in treating psychiatric conditions. The dorsal lateral prefrontal cortex (DLPFC) is typically targeted for stimulation, with magnetic field intensity being calibrated by establishing resting motor threshold (RMT) at hand region of primary motor cortex (M1 hand). This presumes that scalp-to-cortex distance (SCD) and cortical thickness is similar at both sites. We present data from a patient who had very asymmetrical RMTs (47 and 78). We investigated SCDs in this patient at the M1 hand and DLPFC, and the M1 hand cortical thickness. We also investigated TMS electric field distribution. The M1 hand SCD and cortical thickness of the M1 hand was larger on the side with higher RMT. Electric field finite element modelling demonstrated the focal point did not effectively reach the M1 hand with higher RMT as the postcentral gyrus was shunting it. Hence, successful DLPFC treatment was based upon the side with lower RMT. This study highlights the importance of tailoring DLPFC treatment intensity not only based on RMT at the M1 hand, and upon the degree to which SCD distance differs between sites, but also based upon size, shape, and density of M1 hand, as well as electric field distribution. Bioelectromagnetics. 37:130-135, 2016. © 2016 Wiley Periodicals, Inc. PMID:26866631

  17. The influence of motor expertise on the brain activity of motor task performance: A meta-analysis of functional magnetic resonance imaging studies.

    PubMed

    Yang, Jie

    2015-06-01

    Previous research has investigated the influence of long-term motor training on the brain activity of motor processes, but the findings are inconsistent. To clarify how acquiring motor expertise induces cortical reorganization during motor task performance, the current study conducted a quantitative meta-analysis on 26 functional magnetic resonance imaging (fMRI) studies that investigate motor task performance in people with long-term motor training experience (e.g., athletes, musicians, and dancers) and control participants. Meta-analysis of the brain activation in motor experts and novices showed similar effects in the bilateral frontal and parietal regions. The meta-analysis on the contrast between motor experts and novices indicated that experts showed stronger effects in the left inferior parietal lobule (BA 40) than did novices in motor execution and prediction tasks. In motor observation tasks, experts showed stronger effects in the left inferior frontal gyrus (BA 9) and left precentral gyrus (BA 6) than novices. On the contrary, novices had stronger effects in the right motor areas and basal ganglia as compared with motor experts. These results indicate that motor experts have effect increases in brain areas involved in action planning and action comprehension, and suggest that intensive motor training might elaborate the motor representation related to the task performance. PMID:25450866

  18. Reduced heat pain thresholds after sad-mood induction are associated with changes in thalamic activity.

    PubMed

    Wagner, Gerd; Koschke, Mandy; Leuf, Tanja; Schlösser, Ralf; Bär, Karl-Jürgen

    2009-03-01

    Negative affective states influence pain processing in healthy subjects in terms of augmented pain experience. Furthermore, our previous studies revealed that patients with major depressive disorder showed increased heat pain thresholds on the skin. Potential neurofunctional correlates of this finding were located within the fronto-thalamic network. The aim of the present study was to investigate the neurofunctional underpinnings of the influence of sad mood upon heat pain processing in healthy subjects. For this purpose, we used a combination of the Velten Mood Induction procedure and a piece of music to induce sad affect. Initially we assessed heat pain threshold after successful induction of sad mood outside the MR scanner in Experiment 1. We found a highly significant reduction in heat pain threshold on the left hand and a trend for the right. In Experiment 2, we applied thermal pain stimuli on the left hand (37, 42, and 45 degrees C) in an MRI scanner. Subjects were scanned twice, one group before and after sad-mood induction and another group before and after neutral-mood induction, respectively. Our main finding was a significant group x mood-induction interaction bilaterally in the ventrolateral nucleus of the thalamus indicating a BOLD signal increase after sad-mood induction and a BOLD signal decrease in the control group. We present evidence that induced sad affect leads to reduced heat pain thresholds in healthy subjects. This is probably due to altered lateral thalamic activity, which is potentially associated with changed attentional processes. PMID:19027763

  19. Lagged association between geomagnetic activity and diminished nocturnal pain thresholds in mice.

    PubMed

    Galic, M A; Persinger, M A

    2007-10-01

    A wide variety of behaviors in several species has been statistically associated with the natural variations in geomagnetism. To examine whether changes in geomagnetic activity are associated with pain thresholds, adult mice were exposed to a hotplate paradigm once weekly for 52 weeks during the dark cycle. Planetary A index values from the previous 6 days of a given hotplate session were correlated with the mean response latency for subjects to the thermal stimulus. We found that hotplate latency was significantly (P < 0.05) and inversely correlated (rho = -0.25) with the daily geomagnetic intensity 3 days prior to testing. Therefore, if the geomagnetic activity was greater 3 days before a given hotplate trial, subjects tended to exhibit shorter response latencies, suggesting lower pain thresholds or less analgesia. These results are supported by related experimental findings and suggest that natural variations in geomagnetic intensity may influence nociceptive behaviors in mice. PMID:17657732

  20. Detection Thresholds of Falling Snow from Satellite-Borne Active and Passive Sensors

    NASA Technical Reports Server (NTRS)

    Jackson, Gail

    2012-01-01

    Precipitation, including rain and snow, is a critical part of the Earth's energy and hydrology cycles. In order to collect information on the complete global precipitation cycle and to understand the energy budget in terms of precipitation, uniform global estimates of both liquid and frozen precipitation must be collected. Active observations of falling snow are somewhat easier to estimate since the radar will detect the precipitation particles and one only needs to know surface temperature to determine if it is liquid rain or snow. The challenges of estimating falling snow from passive spaceborne observations still exist though progress is being made. While these challenges are still being addressed, knowledge of their impact on expected retrieval results is an important key for understanding falling snow retrieval estimations. Important information to assess falling snow retrievals includes knowing thresholds of detection for active and passive sensors, various sensor channel configurations, snow event system characteristics, snowflake particle assumptions, and surface types. For example, can a lake effect snow system with low (2.5 km) cloud tops having an ice water content (Iwe) at the surface of 0.25 g m-3 and dendrite snowflakes be detected? If this information is known, we can focus retrieval efforts on detectable storms and concentrate advances on achievable results. Here, the focus is to determine thresholds of detection for falling snow for various snow conditions over land and lake surfaces. The analysis relies on simulated Weather Research Forecasting (WRF) simulations of falling snow cases since simulations provide all the information to determine the measurements from space and the ground truth. Results are presented for active radar at Ku, Ka, and W-band and for passive radiometer channels from 10 to 183 GHz (Skofronick-Jackson, et al. submitted to IEEE TGRS, April 2012). The notable results show: (1) the W-Band radar has detection thresholds more

  1. Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex

    PubMed Central

    Lu, Yao; Truccolo, Wilson; Wagner, Fabien B.; Vargas-Irwin, Carlos E.; Ozden, Ilker; Zimmermann, Jonas B.; May, Travis; Agha, Naubahar S.; Wang, Jing

    2015-01-01

    Transient gamma-band (40–80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions. PMID:25761956

  2. Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex.

    PubMed

    Lu, Yao; Truccolo, Wilson; Wagner, Fabien B; Vargas-Irwin, Carlos E; Ozden, Ilker; Zimmermann, Jonas B; May, Travis; Agha, Naubahar S; Wang, Jing; Nurmikko, Arto V

    2015-06-01

    Transient gamma-band (40-80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions. PMID:25761956

  3. Temperature thresholds for chlorine activation and ozone loss in the polar stratosphere

    NASA Astrophysics Data System (ADS)

    Drdla, K.; Müller, R.

    2012-07-01

    Low stratospheric temperatures are known to be responsible for heterogeneous chlorine activation that leads to polar ozone depletion. Here, we discuss the temperature threshold below which substantial chlorine activation occurs. We suggest that the onset of chlorine activation is dominated by reactions on cold binary aerosol particles, without the formation of polar stratospheric clouds (PSCs), i.e. without any significant uptake of HNO3 from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, TACL, is derived. At typical stratospheric conditions, TACL is similar in value to TNAT (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. TNAT is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause TACL to differ from TNAT: TACL is dependent upon H2O and potential temperature, but unlike TNAT is not dependent upon HNO3. Furthermore, in contrast to TNAT, TACL is dependent upon the stratospheric sulfate aerosol loading and thus provides a means to estimate the impact on polar ozone of strong volcanic eruptions and some geo-engineering options, which are discussed. A parameterisation of TACL is provided here, allowing it to be calculated for low solar elevation (or high solar zenith angle) over a comprehensive range of stratospheric conditions. Considering TACL as a proxy for chlorine activation cannot replace a detailed model calculation, and polar ozone loss is influenced by other factors apart from the initial chlorine activation. However, TACL provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than TNAT.

  4. Comparison of acute effects of heroin and Kerack on sensory and motor activity of honey bees (Apis mellifera)

    PubMed Central

    Hassanpour-Ezatti, Majid

    2015-01-01

    Objective(s): Previous studies demonstrated a functional similarity between vertebrate and honey bee nervous systems. The aim of the present study was to compare the effects of heroin and Iranian street Kerack, a combination of heroin and caffeine, on sensory threshold and locomotor activity in honey bees. Materials and Methods: All drugs were given orally to honey bees 30 min before each experiment. The levels of these drugs and their metabolites in brain samples of honey bees were determined by GC/MS. The sucrose sensitivity test was used for evaluation of changes in honey bees’ sensory threshold. Following the administration of both drugs, the honey bees’ locomotor activity changes were evaluated in open fields. Results: 6-acetylmorphine had a higher concentration in comparison with other heroin metabolites in honey bees’ brains. Concentration of the compound in the brain was directly proportional to the amount ingested. Heroin reduced the sensory threshold of honey bees, but Kerack increased it in the same doses. Locomotor activity of honey bee in open field was enhanced after the administration of both drugs. However, immobility time of honey bees was only affected by high doses of heroin. Conclusion: Acute effects of heroin andKerack on the sensory and motor functions of honey bees were different. Findings of this research suggest that these differences originated from the activation of different neurotransmitter systems by caffeine together with activation of opioid receptors by heroin. PMID:26019799

  5. Activity of motor cortex neurons during backward locomotion

    PubMed Central

    Deliagina, T. G.; Orlovsky, G. N.; Karayannidou, A.; Stout, E. E.; Sirota, M. G.; Beloozerova, I. N.

    2011-01-01

    Forward walking (FW) and backward walking (BW) are two important forms of locomotion in quadrupeds. Participation of the motor cortex in the control of FW has been intensively studied, whereas cortical activity during BW has never been investigated. The aim of this study was to analyze locomotion-related activity of the motor cortex during BW and compare it with that during FW. For this purpose, we recorded activity of individual neurons in the cat during BW and FW. We found that the discharge frequency in almost all neurons was modulated in the rhythm of stepping during both FW and BW. However, the modulation patterns during BW and FW were different in 80% of neurons. To determine the source of modulating influences (forelimb controllers vs. hindlimb controllers), the neurons were recorded not only during quadrupedal locomotion but also during bipedal locomotion (with either forelimbs or hindlimbs walking), and their modulation patterns were compared. We found that during BW (like during FW), modulation in some neurons was determined by inputs from limb controllers of only one girdle, whereas the other neurons received inputs from both girdles. The combinations of inputs could depend on the direction of locomotion. Most often (in 51% of forelimb-related neurons and in 34% of the hindlimb-related neurons), the neurons received inputs only from their own girdle when this girdle was leading and from both girdles when this girdle was trailing. This reconfiguration of inputs suggests flexibility of the functional roles of individual cortical neurons during different forms of locomotion. PMID:21430283

  6. Motor imagery-based brain activity parallels that of motor execution: evidence from magnetic source imaging of cortical oscillations.

    PubMed

    Kraeutner, Sarah; Gionfriddo, Alicia; Bardouille, Timothy; Boe, Shaun

    2014-11-01

    Motor imagery (MI) is a form of practice in which an individual mentally performs a motor task. Previous research suggests that skill acquisition via MI is facilitated by repetitive activation of brain regions in the sensorimotor network similar to that of motor execution, however this evidence is conflicting. Further, many studies do not control for overt muscle activity and thus the activation patterns reported for MI may be driven in part by actual movement. The purpose of the current research is to further establish MI as a secondary modality of skill acquisition by providing electrophysiological evidence of an overlap between brain areas recruited for motor execution and imagery. Non-disabled participants (N=18; 24.7±3.8 years) performed both execution and imagery of a unilateral sequence button-press task. Magnetoencephalography (MEG) was utilized to capture neural activity, while electromyography used to rigorously monitor muscle activity. Event-related synchronization/desynchronization (ERS/ERD) analysis was conducted in the beta frequency band (15-30 Hz). Whole head dual-state beamformer analysis was applied to MEG data and 3D t-tests were conducted after Talairach normalization. Source-level analysis showed that MI has similar patterns of spatial activity as ME, including activation of contralateral primary motor and somatosensory cortices. However, this activation is significantly less intense during MI (p<0.05). As well, activation during ME was more lateralized (i.e., within the contralateral hemisphere). These results confirm that ME and MI have similar spatial activation patterns. Thus, the current research provides direct electrophysiological evidence to further establish MI as a secondary form of skill acquisition. PMID:25251592

  7. Sport stacking activities in school children's motor skill development.

    PubMed

    Li, Yuhua; Coleman, Diane; Ransdell, Mary; Coleman, Lyndsie; Irwin, Carol

    2011-10-01

    This study examined the impact of a 12-wk. sport stacking intervention on reaction time (RT), manual dexterity, and hand-eye coordination in elementary school-aged children. 80 Grade 2 students participated in a 15-min. sport stacking practice session every school day for 12 wk., and were tested on psychomotor performance improvement. Tests for choice RT, manual dexterity, and photoelectric rotary pursuit tracking were conducted pre- and post-intervention for both experimental group (n = 36) and the controls (n = 44) who did no sport stacking. Students who had the intervention showed a greater improvement in two-choice RT. No other group difference was found. Such sport stacking activities may facilitate children's central processing and perceptual-motor integration. PMID:22185058

  8. Motor unit regulation of mammalian pharyngeal dilator muscle activity.

    PubMed Central

    van Lunteren, E; Dick, T E

    1989-01-01

    The present study examined the cellular regulation of one of the pharyngeal dilator muscles, the geniohyoid, by assessing its motor unit (MU) behavior in anesthetized cats. During spontaneous breathing, MU that (a) were active during inspiration only (I-MU) and (b) were active during both inspiration and expiration (I/E-MU) were identified. I-MU had a later inspiratory onset time and a shorter duration of inspiratory firing than did I/E-MU (P less than 0.002 and P less than 0.0001, respectively). I-MU were usually quiescent whereas I/E-MU were usually active during the last 20% of inspiration. I/E-MU fired more rapidly (P less than 0.00001) and for relatively longer periods of time (P less than 0.00001) during inspiration than during expiration. End-expiratory airway occlusion (preventing lung expansion during inspiration) augmented the inspiratory activity of both I-MU and I/E-MU. Conversely, end-expiratory airway occlusion reduced the absolute and relative firing durations (P less than 0.002 and P less than 0.00002, respectively) and the firing frequency (P less than 0.001) of I/E-MU activity during expiration. These results indicate that (a) the complex pattern of pharyngeal dilator muscle activity is due to the integrated activity of a heterogeneous group of MU, (b) changes in the degree to which pharyngeal dilator muscles are active result from combinations of MU recruitment/decruitment and modulations of the frequency and duration of MU firing, and (c) gating of lung-volume afferent information occurs during the respiratory cycle. PMID:2760202

  9. CD43 REGULATES THE THRESHOLD FOR T CELL ACTIVATION BY TARGETING CBL FUNCTIONS

    PubMed Central

    Pedraza-Alva, Gustavo; Lilia, B. Mérida; del Rio, Roxana; Nora, A. Fierro; Cruz-Muñoz, Mario E.; Olivares, Norma; Melchy, Erika; Igras, Vivian; Georg, A. Holländer; Steven, J. Burakoff; Rosenstein, Yvonne

    2013-01-01

    SUMMARY T cell (TC) activation requires the coordinated signaling of the T cell receptor (TCR) and co-receptor molecules, allowing TCs to respond to lower degrees of TCR occupancy. Co-receptor molecules set the threshold for TC activation by controlling different regulatory signaling loops. The Cbl family members prevent undesired activation of TCs by regulating TCR signals. In this report we show that TC pre-stimulation by the CD43 co-receptor molecule before TCR engagement inhibits TCR-dependent c-Cbl tyrosine phosphorylation, c-Cbl interaction with the adapter molecule Crk-L and promotes Cbl-b degradation in a PKCθ–dependent manner. Consequently, the prolonged tyrosine phosphorylation and delayed degradation of ZAP-70 and of the ζ chain lead to enhanced MAPK activation and robust TC response. These data indicates that CD43-mediated signals lower the threshold for TC activation by restricting the c-Cbl and Cbl-b inhibitory effects on TCR signaling. In addition to the strength and duration of intracellular signals, our data underscore temporality with which certain molecules are engaged as yet another mechanism to fine tune TC signal quality, and ultimately immune function. PMID:21905200

  10. An Active Contour Model Based on Adaptive Threshold for Extraction of Cerebral Vascular Structures

    PubMed Central

    Wang, Jiaxin; Zhao, Shifeng; Liu, Zifeng; Duan, Fuqing; Pan, Yutong

    2016-01-01

    Cerebral vessel segmentation is essential and helpful for the clinical diagnosis and the related research. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. This study proposes a new active contour model (ACM) implemented by the level-set method for segmenting vessels from TOF-MRA data. The energy function of the new model, combining both region intensity and boundary information, is composed of two region terms, one boundary term and one penalty term. The global threshold representing the lower gray boundary of the target object by maximum intensity projection (MIP) is defined in the first-region term, and it is used to guide the segmentation of the thick vessels. In the second term, a dynamic intensity threshold is employed to extract the tiny vessels. The boundary term is used to drive the contours to evolve towards the boundaries with high gradients. The penalty term is used to avoid reinitialization of the level-set function. Experimental results on 10 clinical brain data sets demonstrate that our method is not only able to achieve better Dice Similarity Coefficient than the global threshold based method and localized hybrid level-set method but also able to extract whole cerebral vessel trees, including the thin vessels. PMID:27597878

  11. Fractional killing arises from cell-to-cell variability in overcoming a caspase activity threshold

    PubMed Central

    Roux, Jérémie; Hafner, Marc; Bandara, Samuel; Sims, Joshua J; Hudson, Hannah; Chai, Diana; Sorger, Peter K

    2015-01-01

    When cells are exposed to death ligands such as TRAIL, a fraction undergoes apoptosis and a fraction survives; if surviving cells are re-exposed to TRAIL, fractional killing is once again observed. Therapeutic antibodies directed against TRAIL receptors also cause fractional killing, even at saturating concentrations, limiting their effectiveness. Fractional killing arises from cell-to-cell fluctuations in protein levels (extrinsic noise), but how this results in a clean bifurcation between life and death remains unclear. In this paper, we identify a threshold in the rate and timing of initiator caspase activation that distinguishes cells that live from those that die; by mapping this threshold, we can predict fractional killing of cells exposed to natural and synthetic agonists alone or in combination with sensitizing drugs such as bortezomib. A phenomenological model of the threshold also quantifies the contributions of two resistance genes (c-FLIP and Bcl-2), providing new insight into the control of cell fate by opposing pro-death and pro-survival proteins and suggesting new criteria for evaluating the efficacy of therapeutic TRAIL receptor agonists. PMID:25953765

  12. Fractional killing arises from cell-to-cell variability in overcoming a caspase activity threshold.

    PubMed

    Roux, Jérémie; Hafner, Marc; Bandara, Samuel; Sims, Joshua J; Hudson, Hannah; Chai, Diana; Sorger, Peter K

    2015-05-01

    When cells are exposed to death ligands such as TRAIL, a fraction undergoes apoptosis and a fraction survives; if surviving cells are re-exposed to TRAIL, fractional killing is once again observed. Therapeutic antibodies directed against TRAIL receptors also cause fractional killing, even at saturating concentrations, limiting their effectiveness. Fractional killing arises from cell-to-cell fluctuations in protein levels (extrinsic noise), but how this results in a clean bifurcation between life and death remains unclear. In this paper, we identify a threshold in the rate and timing of initiator caspase activation that distinguishes cells that live from those that die; by mapping this threshold, we can predict fractional killing of cells exposed to natural and synthetic agonists alone or in combination with sensitizing drugs such as bortezomib. A phenomenological model of the threshold also quantifies the contributions of two resistance genes (c-FLIP and Bcl-2), providing new insight into the control of cell fate by opposing pro-death and pro-survival proteins and suggesting new criteria for evaluating the efficacy of therapeutic TRAIL receptor agonists. PMID:25953765

  13. An Active Contour Model Based on Adaptive Threshold for Extraction of Cerebral Vascular Structures.

    PubMed

    Wang, Jiaxin; Zhao, Shifeng; Liu, Zifeng; Tian, Yun; Duan, Fuqing; Pan, Yutong

    2016-01-01

    Cerebral vessel segmentation is essential and helpful for the clinical diagnosis and the related research. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. This study proposes a new active contour model (ACM) implemented by the level-set method for segmenting vessels from TOF-MRA data. The energy function of the new model, combining both region intensity and boundary information, is composed of two region terms, one boundary term and one penalty term. The global threshold representing the lower gray boundary of the target object by maximum intensity projection (MIP) is defined in the first-region term, and it is used to guide the segmentation of the thick vessels. In the second term, a dynamic intensity threshold is employed to extract the tiny vessels. The boundary term is used to drive the contours to evolve towards the boundaries with high gradients. The penalty term is used to avoid reinitialization of the level-set function. Experimental results on 10 clinical brain data sets demonstrate that our method is not only able to achieve better Dice Similarity Coefficient than the global threshold based method and localized hybrid level-set method but also able to extract whole cerebral vessel trees, including the thin vessels. PMID:27597878

  14. Specific Inhibition of Cyclin-dependent Kinase 5 Activity Induces Motor Neuron Development in vivo

    PubMed Central

    Kanungo, Jyotshnabala; Zheng, Ya-Li; Amin, Niranjana D.; Kaur, Sukhbir; Ramchandran, Ramani; Pant, Harish C.

    2009-01-01

    Cyclin-dependent kinase 5 (cdk5) is a ubiquitous protein activated by specific activators, p35 and p39. Cdk5 regulates neuronal migration, differentiation, axonogenesis, synaptic transmission and apoptosis. However, its role in motor neuron development remains unexplored. Here, using gain and loss-of-function analyses in developing zebrafish embryos, we report that cdk5 plays a critical role in spinal and cranial motor neuron development. Cdk5 knockdown results in supernumerary spinal and cranial motor neurons. While a dominant negative, kinase-dead cdk5 promotes the generation of supernumerary motor neurons; over-expression of cdk5 suppresses motor neuron development. Thus, modulating cdk5 activity seems promising in inducing motor neuron development in vivo. PMID:19523926

  15. The effects of smartphone use on upper extremity muscle activity and pain threshold.

    PubMed

    Lee, Minkyung; Hong, Yunkyung; Lee, Seunghoon; Won, Jinyoung; Yang, Jinjun; Park, Sookyoung; Chang, Kyu-Tae; Hong, Yonggeun

    2015-06-01

    [Purpose] The purpose of this study was to determine whether muscle activity and pressure-induced pain in the upper extremities are affected by smartphone use, and to compare the effects of phone handling with one hand and with both hands. [Subjects] The study subjects were asymptomatic women 20-22 years of age. [Methods] The subjects sat in a chair with their feet on the floor and the elbow flexed, holding a smartphone positioned on the thigh. Subsequently, the subjects typed the Korean anthem for 3 min, one-handed or with both hands. Each subject repeated the task three times, with a 5-min rest period between tasks to minimize fatigue. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor pollicis longus (EPL), and abductor pollicis (AP) during phone operation. We also used a dolorimeter to measure the pressure-induced pain threshold in the UT. [Results] We observed higher muscle activity in the UT, AP, and EPL in one-handed smartphone use than in its two-handed use. The pressure-induced pain threshold of the UT was lower after use of the smartphone, especially after one-handed use. [Conclusion] Our results show that smartphone operation with one hand caused greater UT pain and induced increased upper extremity muscle activity. PMID:26180311

  16. The effects of smartphone use on upper extremity muscle activity and pain threshold

    PubMed Central

    Lee, Minkyung; Hong, Yunkyung; Lee, Seunghoon; Won, Jinyoung; Yang, Jinjun; Park, Sookyoung; Chang, Kyu-Tae; Hong, Yonggeun

    2015-01-01

    [Purpose] The purpose of this study was to determine whether muscle activity and pressure-induced pain in the upper extremities are affected by smartphone use, and to compare the effects of phone handling with one hand and with both hands. [Subjects] The study subjects were asymptomatic women 20–22 years of age. [Methods] The subjects sat in a chair with their feet on the floor and the elbow flexed, holding a smartphone positioned on the thigh. Subsequently, the subjects typed the Korean anthem for 3 min, one-handed or with both hands. Each subject repeated the task three times, with a 5-min rest period between tasks to minimize fatigue. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor pollicis longus (EPL), and abductor pollicis (AP) during phone operation. We also used a dolorimeter to measure the pressure-induced pain threshold in the UT. [Results] We observed higher muscle activity in the UT, AP, and EPL in one-handed smartphone use than in its two-handed use. The pressure-induced pain threshold of the UT was lower after use of the smartphone, especially after one-handed use. [Conclusion] Our results show that smartphone operation with one hand caused greater UT pain and induced increased upper extremity muscle activity. PMID:26180311

  17. Phasic motor activity reduction occurring with horizontal rapid eye movements during active sleep in human.

    PubMed

    Kohyama, J; Shimohira, M; Hasegawa, T; Kouji, T; Iwakawa, Y

    1995-01-01

    We describe the phasic reduction of motor activity occurring with horizontal rapid eye movements (REMs) during active sleep in 15 children (12 healthy children and 3 patients with severe brain damage). A REM-related decrease in intercostal muscle activity was demonstrated by averaging integrated surface electromyograms. In the healthy subjects, this reduction had a mean latency from the REM onset of 37.1 ms and a duration of 225.9 ms. This phenomenon was also observed in the 3 patients who had lost cerebral function. We hypothesized a brainstem origin for the effect. A REM-related mentalis muscle activity loss, detected by averaging mentalis muscle twitches, was observed in 10 healthy children among the subjects. This loss began at 59.1 ms before the onset of REMs and lasted for 230.2 ms on average. In addition, a transient decrease in integrated REM activity surrounding mentalis muscle twitches (a twitch-related reduction of REMs) was observed. We discuss the similarity between REM-related phasic reduction of muscle activity obtained for intercostal and mentalis muscles and pontogeniculo-occipital (PGO) wave-related inhibitory postsynaptic potentials reported for feline lumbar and trigeminal motoneurons, respectively. We then assume the presence of a phasic event generator, functioning during active sleep in healthy humans, which triggers at least three generators; that is, the generator of PGO waves (or REMs), motor inhibition, and of motor excitation including muscle twitches. PMID:8751071

  18. Activity of nodes reshapes the critical threshold of spreading dynamics in complex networks

    NASA Astrophysics Data System (ADS)

    Liu, Chen; Zhou, Li-xin; Fan, Chong-jun; Huo, Liang-an; Tian, Zhan-wei

    2015-08-01

    In this paper, we investigate spreading dynamics on complex networks with active nodes based on SIR (Susceptible-Infected-Removed) model. Different from previous studies, each node of the network rotates between active state and inactive state according to certain probabilities. An active susceptible node can be infected by all its infected neighbors, while an inactive susceptible node can only be infected by its active infected neighbors. By means of ​mean-field approach and numerical simulations, we explore the critical phenomenon by the combined effects of activity rate and infection rate on spreading dynamics. We show that the critical threshold of infection rate is increased by node activity, and node activity also shows a critical phenomenon given certain infection rate. On the whole, there exists a critical curve consists of pairs of critical activity rate and infection rate. We also analyze theoretically the impact of activity rate and infection rate on the final size of spreading dynamics, which is verified by numerical simulations. This work complements our understanding of spreading dynamics with active nodes and may be used to develop more feasible and more economical methods to control spreading dynamics.

  19. Divalent cations potentiate TRPV1 channel by lowering the heat activation threshold

    PubMed Central

    Cao, Xu; Ma, Linlin; Yang, Fan

    2014-01-01

    Transient receptor potential vanilloid type 1 (TRPV1) channel responds to a wide spectrum of physical and chemical stimuli. In doing so, it serves as a polymodal cellular sensor for temperature change and pain. Many chemicals are known to strongly potentiate TRPV1 activation, though how this is achieved remains unclear. In this study we investigated the molecular mechanism underlying the gating effects of divalent cations Mg2+ and Ba2+. Using a combination of fluorescence imaging and patch-clamp analysis, we found that these cations potentiate TRPV1 gating by most likely promoting the heat activation process. Mg2+ substantially lowers the activation threshold temperature; as a result, a significant fraction of channels are heat-activated at room temperature. Although Mg2+ also potentiates capsaicin- and voltage-dependent activation, these processes were found either to be not required (in the case of capsaicin) or insufficient (in the case of voltage) to mediate the activating effect. In support of a selective effect on heat activation, Mg2+ and Ba2+ cause a Ca2+-independent desensitization that specifically prevents heat-induced channel activation but does not prevent capsaicin-induced activation. These results can be satisfactorily explained within an allosteric gating framework in which divalent cations strongly promote the heat-dependent conformational change or its coupling to channel activation, which is further coupled to the voltage- and capsaicin-dependent processes. PMID:24344247

  20. Monitoring tectal neuronal activities and motor behavior in zebrafish larvae.

    PubMed

    Sumbre, Germán; Poo, Mu-Ming

    2013-09-01

    To understand how visuomotor behaviors are controlled by the nervous system, it is necessary to monitor the activity of large populations of neurons with single-cell resolution over a large area of the brain in a relatively simple, behaving organism. The zebrafish larva, a small lower vertebrate with transparent skin, serves as an excellent model for this purpose. Immediately after the larva hatches, it needs to catch prey and avoid predators. This strong evolutionary pressure leads to the rapid development of functional sensory systems, particularly vision. By 5 d postfertilization (dpf), tectal cells show distinct visually evoked patterns of activation, and the larvae are able to perform a variety of visuomotor behaviors. During the early larval stage, zebrafish breathe mainly through the skin and can be restrained under the microscope using a drop of low-melting-point agarose, without the use of anesthetics. Moreover, the transparency of the skin, the small diameter of the neurons (4-5 µm), and the high-neuronal density enable the use of in vivo noninvasive imaging techniques to monitor neuronal activities of up to ∼500 cells within the central nervous system, still with single-cell resolution. This article describes a method for simultaneously monitoring spontaneous and visually evoked activities of large populations of neurons in the optic tectum of the zebrafish larva, using a synthetic calcium dye (Oregon Green BAPTA-1 AM) and a conventional confocal or two-photon scanning fluorescence microscope, together with a method for measuring the tail motor behavior of the head-immobilized zebrafish larva. PMID:24003199

  1. Stem cell cytoskeleton is slaved to active motors

    NASA Astrophysics Data System (ADS)

    Rehfeldt, Florian; Brown, Andre; Engler, Adam; Discher, Dennis

    2007-03-01

    Cells feel their physical microenvironment through their adhesion and respond to it in various ways. Indeed, matrix elasticity can even guide the differentiation of human adult mesenchymal stem cells (MSCs) [Engler et al. Cell 2006]. Sparse cultures of MSCs on elastic collagen--coated substrates that are respectively soft, stiff, or extremely stiff were shown to induce neurogenesis, myogenesis, and osteogenesis. Lineage commitment was evaluated by morphological analysis, protein expression profiles, and transcription microarrays. Differentiation could be completely blocked with a specific non-muscle myosin II (NMM II) inhibitor, suggesting that contractile motor activity is essential for the cells to sense matrix elasticity. Current studies by AFM and near-field fluorescence imaging show that NMM II inhibition in stem cells on rigid glass surfaces promotes actin-rich dendritic outgrowth resembling neurite extension. Dynamic cell studies have been conducted to elucidate the complex molecular interplay of the contractile apparatus in response to selected physical and biochemical stimuli. Additional insight is being gained by using AFM to investigate the local elasticity of the cell's cytoskeletal force sensing machinery.

  2. Reduced endplate currents underlie motor unit dysfunction in canine motor neuron disease.

    PubMed

    Rich, Mark M; Waldeck, Robert F; Cork, Linda C; Balice-Gordon, Rita J; Fyffe, Robert E W; Wang, Xueyong; Cope, Timothy C; Pinter, Martin J

    2002-12-01

    Hereditary canine spinal muscular atrophy (HCSMA) is an autosomal dominant degenerative disorder of motor neurons. In homozygous animals, motor units produce decreased force output and fail during repetitive activity. Previous studies suggest that decreased efficacy of neuromuscular transmission underlies these abnormalities. To examine this, we recorded muscle fiber endplate currents (EPCs) and found reduced amplitudes and increased failures during nerve stimulation in homozygotes compared with wild-type controls. Comparison of EPC amplitudes with muscle fiber current thresholds indicate that many EPCs from homozygotes fall below threshold for activating muscle fibers but can be raised above threshold following potentiation. To determine whether axonal abnormalities might play a role in causing motor unit dysfunction, we examined the postnatal maturation of axonal conduction velocity in relation to the appearance of tetanic failure. We also examined intracellularly labeled motor neurons for evidence of axonal neurofilament accumulations, which are found in many instances of motor neuron disease including HCSMA. Despite the appearance of tetanic failure between 90 and 120 days, average motor axon conduction velocity increased with age in homozygotes and achieved adult levels. Normal correlations between motor neuron properties (including conduction velocity) and motor unit properties were also observed. Labeled proximal motor axons of several motor neurons that supplied failing motor units exhibited little or no evidence of axonal swellings. We conclude that decreased release of transmitter from motor terminals underlies motor unit dysfunction in HCSMA and that the mechanisms determining the maturation of axonal conduction velocity and the pattern of correlation between motor neuron and motor unit properties do not contribute to the appearance or evolution of motor unit dysfunction. PMID:12466447

  3. NAC selectively inhibit cancer telomerase activity: A higher redox homeostasis threshold exists in cancer cells.

    PubMed

    Li, Pengying; Wu, Meilin; Wang, Jing; Sui, Yilun; Liu, Shanlin; Shi, Dongyun

    2016-08-01

    Telomerase activity controls telomere length, and this plays an important role in stem cells, aging and tumors. Antioxidant was shown to protect telomerase activity in normal cells but inhibit that in cancer cells, but the underlying mechanism is elusive. Here we found that 7721 hepatoma cells held a higher redox homeostasis threshold than L02 normal liver cells which caused 7721 cells to have a higher demand for ROS; MnSOD over-expression in 7721 decreased endogenous reactive oxygen species (ROS) and inhibited telomerase activity; Akt phosphorylation inhibitor and NAC both inhibited 7721 telomerase activity. The over-elimination of ROS by NAC resulted in the inhibition of Akt pathway. Our results suggest that ROS is involved in the regulation of cancer telomerase activity through Akt pathway. The different intracellular redox homeostasis and antioxidant system in normal cells and tumor cells may be the cause of the opposite effect on telomerase activity in response to NAC treatment. Our results provide a theoretical base of using antioxidants selectively inhibit cancer telomerase activity. Findings of the present study may provide insights into novel approaches for cancer treatment. PMID:26771767

  4. Comparison of activation of corticospinal neurons and spinal motor neurons by magnetic and electrical transcranial stimulation in the lumbosacral cord of the anaesthetized monkey.

    PubMed

    Edgley, S A; Eyre, J A; Lemon, R N; Miller, S

    1997-05-01

    To illuminate the action of non-invasive stimuli on the human cerebral cortex, responses of corticospinal axons and of plantar alpha-motor neurons following transcranial magnetic (TMS) and electrical stimulation (TES) were recorded in the lumbosacral cord in the anaesthetized macaque monkey. A round coil was used for TMS, and the anode was located at the vertex for TES. The responses of 175 identified corticospinal axons (conduction velocities of 24-95 m/s) were recorded from the lateral corticospinal tract at the T12-L3 spinal level. A single magnetic or electrical stimulus could evoke an early spike corresponding to the direct (D) wave in surface recorded volleys and was termed a D response. In the same axon, up to four further spikes, termed indirect (I) responses, could also be evoked. At a given intensity of stimulation, D responses had clear thresholds and fixed latencies, whereas I responses were labile in both respects. For TMS and TES, the thresholds of both D and I responses were inversely correlated with axonal conduction velocity. For TMS, fast conducting axons (> 75 m/s) had lower thresholds for D responses, while more slowly conducting axons (< 55 m/s) had lower thresholds for I responses. Very few of the axons with a conduction velocity of < 40 m/s (three out of 23) gave a D response to TMS. For TES, the majority of axons had lower thresholds for D responses or a similar threshold for both D and I responses. At threshold, the latencies of D responses evoked by TMS and TES were consistent with activation within the cortex, while TES also excited some corticospinal axons deep to the cortex. At 2.5 times threshold for the D response, TMS still excited axons mostly within the cortex, but with TES the site of activation shifted by as much as 65 mm below the cortex (mode 20 mm). Intracellular responses were recorded in 23 plantar alpha motor neurons supplying intrinsic muscles of the foot. All showed monosynaptic excitatory post-synaptic potentials (EPSPs

  5. Threshold occupancy and specific cation binding modes in the hammerhead ribozyme active site are required for active conformation

    PubMed Central

    Lee, Tai-Sung; Giambaşu, George M.; Sosa, Carlos P.; Martick, Monika; Scott, William G.; York, Darrin M.

    2009-01-01

    The relationship between formation of active in-line attack conformations and monovalent (Na+) and divalent (Mg2+) metal ion binding in the hammerhead ribozyme has been explored with molecular dynamics simulations. To stabilize repulsions between negatively charged groups, different requirements of threshold occupancy of metal ions were observed in the reactant and activated precursor states both in the presence or absence of a Mg2+ in the active site. Specific bridging coordination patterns of the ions are correlated with the formation of active in-line attack conformations and can be accommodated in both cases. Furthermore, simulation results suggest that the hammerhead ribozyme folds to form an electronegative recruiting pocket that attracts high local concentrations of positive charge. The present simulations help to reconcile experiments that probe the metal ion sensitivity of hammerhead ribozyme catalysis and support the supposition that Mg2+, in addition to stabilizing active conformations, plays a specific chemical role in catalysis. PMID:19265710

  6. Thresholds of toxicological concern for endocrine active substances in the aquatic environment.

    PubMed

    Gross, Melanie; Daginnus, Klaus; Deviller, Genevieve; de Wolf, Watze; Dungey, Stephen; Galli, Corrado; Gourmelon, Anne; Jacobs, Miriam; Matthiessen, Peter; Micheletti, Christian; Nestmann, Earle; Pavan, Manuela; Paya-Perez, Ana; Ratte, Hans-Toni; Safford, Bob; Sokull-Klüttgen, Birgit; Stock, Frauke; Stolzenberg, Hans-Christian; Wheeler, James; Willuhn, Marc; Worth, Andrew; Comenges, Jose Manuel Zaldivar; Crane, Mark

    2010-01-01

    The threshold of toxicological concern (TTC) concept proposes that an exposure threshold value can be derived for chemicals, below which no significant risk to human health or the environment is expected. This concept goes further than setting acceptable exposure levels for individual chemicals, because it attempts to set a de minimis value for chemicals, including those of unknown toxicity, by taking the chemical's structure or mode of action (MOA) into consideration. This study examines the use of the TTC concern concept for endocrine active substances (EAS) with an estrogenic MOA. A case study formed the basis for a workshop of regulatory, industry and academic scientists held to discuss the use of the TTC in aquatic environmental risk assessment. The feasibility and acceptability, general advantages and disadvantages, and the specific issues that need to be considered when applying the TTC concept for EAS in risk assessment were addressed. Issues surrounding the statistical approaches used to derive TTCs were also discussed. This study presents discussion points and consensus findings of the workshop. PMID:19558199

  7. Distribution of Active and Resting Periods in the Motor Activity of Patients with Depression and Schizophrenia

    PubMed Central

    Hauge, Erik; Berle, Jan Øystein; Dilsaver, Steven; Oedegaard, Ketil J.

    2016-01-01

    Objective Alterations of activity are prominent features of the major functional psychiatric disorders. Motor activity patterns are characterized by bursts of activity separated by periods with inactivity. The purpose of the present study has been to analyze such active and inactive periods in patients with depression and schizophrenia. Methods Actigraph registrations for 12 days from 24 patients with schizophrenia, 23 with depression and 29 healthy controls. Results Patients with schizophrenia and depression have distinctly different profiles with regard to the characterization and distribution of active and inactive periods. The mean duration of active periods is lowest in the depressed patients, and the duration of inactive periods is highest in the patients with schizophrenia. For active periods the cumulative probability distribution, using lengths from 1 to 35 min, follows a straight line on a log-log plot, suggestive of a power law function, and a similar relationship is found for inactive periods, using lengths from 1 to 20 min. For both active and inactive periods the scaling exponent is higher in the depressed compared to the schizophrenic patients. Conclusion The present findings add to previously published results, with other mathematical methods, suggesting there are important differences in control systems regulating motor behavior in these two major groups of psychiatric disorders. PMID:26766953

  8. Thresholds for cellular disruption and activation of the stress response in renal epithelia.

    PubMed

    van Why, S K; Kim, S; Geibel, J; Seebach, F A; Kashgarian, M; Siegel, N J

    1999-08-01

    Renal ischemia causes a rapid fall in cellular ATP, increased intracellular calcium (Ca(i)), and dissociation of Na(+)-K(+)-ATPase from the cytoskeleton along with initiation of a stress response. We examined changes in Ca(i), Na(+)-K(+)-ATPase detergent solubility, and activation of heat-shock transcription factor (HSF) in relation to graded reduction of ATP in LLC-PK(1) cells to determine whether initiation of the stress response was related to any one of these perturbations alone. Ca(i) increased first at 75% of control ATP. Triton X-100 solubility of Na(+)-K(+)-ATPase increased below 70% control ATP. Reducing cellular ATP below 50% control consistently activated HSF. Stepped decrements in cellular ATP below the respective thresholds caused incremental increases in Ca(i), Na(+)-K(+)-ATPase solubility, and HSF activation. ATP depletion activated both HSF1 and HSF2. Proteasome inhibition caused activation of HSF1 and HSF2 in a pattern similar to ATP depletion. Lactate dehydrogenase release remained at control levels irrespective of the degree of ATP depletion. Progressive accumulation of nonnative proteins may be the critical signal for the adaptive induction of the stress response in renal epithelia. PMID:10444577

  9. Pattern segmentation with activity dependent natural frequency shift and sub-threshold resonance

    NASA Astrophysics Data System (ADS)

    Shtrahman, E.; Zochowski, M.

    2015-03-01

    Understanding the mechanisms underlying distributed pattern formation in brain networks and its content driven dynamical segmentation is an area of intense study. We investigate a theoretical mechanism for selective activation of diverse neural populations that is based on dynamically shifting cellular resonances in functionally or structurally coupled networks. We specifically show that sub-threshold neuronal depolarization from synaptic coupling or external input can shift neurons into and out of resonance with specific bands of existing extracellular oscillations, and this can act as a dynamic readout mechanism during information storage and retrieval. We find that this mechanism is robust and suggest it as a general coding strategy that can be applied to any network with oscillatory nodes.

  10. Phrenic Long-Term Facilitation Requires PKCθ Activity within Phrenic Motor Neurons

    PubMed Central

    Devinney, Michael J.; Fields, Daryl P.; Huxtable, Adrianne G.; Peterson, Timothy J.; Dale, Erica A.

    2015-01-01

    Acute intermittent hypoxia (AIH) induces a form of spinal motor plasticity known as phrenic long-term facilitation (pLTF); pLTF is a prolonged increase in phrenic motor output after AIH has ended. In anesthetized rats, we demonstrate that pLTF requires activity of the novel PKC isoform, PKCθ, and that the relevant PKCθ is within phrenic motor neurons. Whereas spinal PKCθ inhibitors block pLTF, inhibitors targeting other PKC isoforms do not. PKCθ is highly expressed in phrenic motor neurons, and PKCθ knockdown with intrapleural siRNAs abolishes pLTF. Intrapleural siRNAs targeting PKCζ, an atypical PKC isoform expressed in phrenic motor neurons that underlies a distinct form of phrenic motor plasticity, does not affect pLTF. Thus, PKCθ plays a critical role in spinal AIH-induced respiratory motor plasticity, and the relevant PKCθ is localized within phrenic motor neurons. Intrapleural siRNA delivery has considerable potential as a therapeutic tool to selectively manipulate plasticity in vital respiratory motor neurons. PMID:26019328

  11. Phrenic long-term facilitation requires PKCθ activity within phrenic motor neurons.

    PubMed

    Devinney, Michael J; Fields, Daryl P; Huxtable, Adrianne G; Peterson, Timothy J; Dale, Erica A; Mitchell, Gordon S

    2015-05-27

    Acute intermittent hypoxia (AIH) induces a form of spinal motor plasticity known as phrenic long-term facilitation (pLTF); pLTF is a prolonged increase in phrenic motor output after AIH has ended. In anesthetized rats, we demonstrate that pLTF requires activity of the novel PKC isoform, PKCθ, and that the relevant PKCθ is within phrenic motor neurons. Whereas spinal PKCθ inhibitors block pLTF, inhibitors targeting other PKC isoforms do not. PKCθ is highly expressed in phrenic motor neurons, and PKCθ knockdown with intrapleural siRNAs abolishes pLTF. Intrapleural siRNAs targeting PKCζ, an atypical PKC isoform expressed in phrenic motor neurons that underlies a distinct form of phrenic motor plasticity, does not affect pLTF. Thus, PKCθ plays a critical role in spinal AIH-induced respiratory motor plasticity, and the relevant PKCθ is localized within phrenic motor neurons. Intrapleural siRNA delivery has considerable potential as a therapeutic tool to selectively manipulate plasticity in vital respiratory motor neurons. PMID:26019328

  12. Patterns of presynaptic activity and synaptic strength interact to produce motor output.

    PubMed

    Wright, Terrence Michael; Calabrese, Ronald L

    2011-11-30

    Motor neuron activity is coordinated by premotor networks into a functional motor pattern by complex patterns of synaptic drive. These patterns combine both the temporal pattern of spikes of the premotor network and the profiles of synaptic strengths (i.e., conductances). Given the complexity of premotor networks in vertebrates, it has been difficult to ascertain the relative contributions of temporal patterns and synaptic strength profiles to the motor patterns observed in these animals. Here, we use the leech (Hirudo sp.) heartbeat central pattern generator (CPG), in which we can measure both the temporal pattern and the synaptic strength profiles of the entire premotor network and the motor outflow in individual animals. In this system, a series of motor neurons all receive input from the same premotor interneurons of the CPG but must be coordinated differentially to produce a functional pattern. These properties allow a theoretical and experimental dissection of the rules that govern how temporal patterns and synaptic strength profiles are combined in motor neurons so that functional motor patterns emerge, including an analysis of the impact of animal-to-animal variation in input to such variation in output. In the leech, segmental heart motor neurons are coordinated alternately in a synchronous and peristaltic pattern. We show that synchronous motor patterns result from a nearly synchronous premotor temporal pattern produced by the leech heartbeat CPG. For peristaltic motor patterns, the staggered premotor temporal pattern determines the phase range over which segmental motor neurons can fire while synaptic strength profiles define the intersegmental motor phase progression realized. PMID:22131417

  13. Analysis of automated quantification of motor activity in REM sleep behaviour disorder.

    PubMed

    Frandsen, Rune; Nikolic, Miki; Zoetmulder, Marielle; Kempfner, Lykke; Jennum, Poul

    2015-10-01

    Rapid eye movement (REM) sleep behaviour disorder (RBD) is characterized by dream enactment and REM sleep without atonia. Atonia is evaluated on the basis of visual criteria, but there is a need for more objective, quantitative measurements. We aimed to define and optimize a method for establishing baseline and all other parameters in automatic quantifying submental motor activity during REM sleep. We analysed the electromyographic activity of the submental muscle in polysomnographs of 29 patients with idiopathic RBD (iRBD), 29 controls and 43 Parkinson's (PD) patients. Six adjustable parameters for motor activity were defined. Motor activity was detected and quantified automatically. The optimal parameters for separating RBD patients from controls were investigated by identifying the greatest area under the receiver operating curve from a total of 648 possible combinations. The optimal parameters were validated on PD patients. Automatic baseline estimation improved characterization of atonia during REM sleep, as it eliminates inter/intra-observer variability and can be standardized across diagnostic centres. We found an optimized method for quantifying motor activity during REM sleep. The method was stable and can be used to differentiate RBD from controls and to quantify motor activity during REM sleep in patients with neurodegeneration. No control had more than 30% of REM sleep with increased motor activity; patients with known RBD had as low activity as 4.5%. We developed and applied a sensitive, quantitative, automatic algorithm to evaluate loss of atonia in RBD patients. PMID:25923472

  14. CARA Risk Assessment Thresholds

    NASA Technical Reports Server (NTRS)

    Hejduk, M. D.

    2016-01-01

    Warning remediation threshold (Red threshold): Pc level at which warnings are issued, and active remediation considered and usually executed. Analysis threshold (Green to Yellow threshold): Pc level at which analysis of event is indicated, including seeking additional information if warranted. Post-remediation threshold: Pc level to which remediation maneuvers are sized in order to achieve event remediation and obviate any need for immediate follow-up maneuvers. Maneuver screening threshold: Pc compliance level for routine maneuver screenings (more demanding than regular Red threshold due to additional maneuver uncertainty).

  15. Rectification of SEMG as a tool to demonstrate synchronous motor unit activity during vibration.

    PubMed

    Sebik, Oguz; Karacan, Ilhan; Cidem, Muharrem; Türker, Kemal S

    2013-04-01

    The use of surface electromyography (SEMG) in vibration studies is problematic since motion artifacts occupy the same frequency band with the SEMG signal containing information on synchronous motor unit activity. We hypothesize that using a harsher, 80-500 Hz band-pass filter and using rectification can help eliminate motion artifacts and provide a way to observe synchronous motor unit activity that is phase locked to vibration using SEMG recordings only. Multi Motor Unit (MMU) action potentials using intramuscular electrodes along with SEMG were recorded from the gastrocnemius medialis (GM) of six healthy male volunteers. Data were collected during whole body vibration, using vibration frequencies of 30 Hz, 35 Hz, 40 Hz or 50 Hz. A computer simulation was used to investigate the efficacy of filtering under different scenarios: with or without artifacts and/or motor unit synchronization. Our findings indicate that motor unit synchronization took place during WBV as verified by MMU recordings. A harsh filtering regimen along with rectification proved successful in demonstrating motor unit synchronization in SEMG recordings. Our findings were further supported by the results from the computer simulation, which indicated that filtering and rectification was efficient in discriminating motion artifacts from motor unit synchronization. We suggest that the proposed signal processing technique may provide a new methodology to evaluate the effects of vibration treatments using only SEMG. This is a major advantage, as this non-intrusive method is able to overcome movement artifacts and also indicate the synchronization of underlying motor units. PMID:23098913

  16. Hypocretinergic neurons are activated in conjunction with goal-oriented survival-related motor behaviors.

    PubMed

    Torterolo, Pablo; Ramos, Oscar V; Sampogna, Sharon; Chase, Michael H

    2011-10-24

    Hypocretinergic neurons are located in the area of the lateral hypothalamus which is responsible for mediating goal-directed, survival-related behaviors. Consequently, we hypothesize that the hypocretinergic system functions to promote these behaviors including those patterns of somatomotor activation upon which they are based. Further, we hypothesize that the hypocretinergic system is not involved with repetitive motor activities unless they occur in conjunction with the goal-oriented behaviors that are governed by the lateral hypothalamus. In order to determine the veracity of these hypotheses, we examined Fos immunoreactivity (as a marker of neuronal activity) in hypocretinergic neurons in the cat during: a) Exploratory Motor Activity; b) Locomotion without Reward; c) Locomotion with Reward; and d) Wakefulness without Motor Activity. Significantly greater numbers of hypocretinergic neurons expressed c-fos when the animals were exploring an unknown environment during Exploratory Motor Activity compared with all other paradigms. In addition, a larger number of Hcrt+Fos+neurons were activated during Locomotion with Reward than during Wakefulness without Motor Activity. Finally, very few hypocretinergic neurons were activated during Locomotion without Reward and Wakefulness without Motor Activity, wherein there was an absence of goal-directed activities. We conclude that the hypocretinergic system does not promote wakefulness per se or motor activity per se but is responsible for mediating specific goal-oriented behaviors that take place during wakefulness. Accordingly, we suggest that the hypocretinergic system is responsible for controlling the somatomotor system and coordinating its activity with other systems in order to produce successful goal-oriented survival-related behaviors that are controlled by the lateral hypothalamus. PMID:21839102

  17. Kinesin-Binding Protein Controls Microtubule Dynamics and Cargo Trafficking by Regulating Kinesin Motor Activity.

    PubMed

    Kevenaar, Josta T; Bianchi, Sarah; van Spronsen, Myrrhe; Olieric, Natacha; Lipka, Joanna; Frias, Cátia P; Mikhaylova, Marina; Harterink, Martin; Keijzer, Nanda; Wulf, Phebe S; Hilbert, Manuel; Kapitein, Lukas C; de Graaff, Esther; Ahkmanova, Anna; Steinmetz, Michel O; Hoogenraad, Casper C

    2016-04-01

    Kinesin motor proteins play a fundamental role for normal neuronal development by controlling intracellular cargo transport and microtubule (MT) cytoskeleton organization. Regulating kinesin activity is important to ensure their proper functioning, and their misregulation often leads to severe human neurological disorders. Homozygous nonsense mutations in kinesin-binding protein (KBP)/KIAA1279 cause the neurological disorder Goldberg-Shprintzen syndrome (GOSHS), which is characterized by intellectual disability, microcephaly, and axonal neuropathy. Here, we show that KBP regulates kinesin activity by interacting with the motor domains of a specific subset of kinesins to prevent their association with the MT cytoskeleton. The KBP-interacting kinesins include cargo-transporting motors such as kinesin-3/KIF1A and MT-depolymerizing motor kinesin-8/KIF18A. We found that KBP blocks KIF1A/UNC-104-mediated synaptic vesicle transport in cultured hippocampal neurons and in C. elegans PVD sensory neurons. In contrast, depletion of KBP results in the accumulation of KIF1A motors and synaptic vesicles in the axonal growth cone. We also show that KBP regulates neuronal MT dynamics by controlling KIF18A activity. Our data suggest that KBP functions as a kinesin inhibitor that modulates MT-based cargo motility and depolymerizing activity of a subset of kinesin motors. We propose that misregulation of KBP-controlled kinesin motors may represent the underlying molecular mechanism that contributes to the neuropathological defects observed in GOSHS patients. PMID:26948876

  18. CORRELATIONS OF PESTICIDE-INDUCED CHOLINESTERASE INHIBITION AND MOTOR ACTIVITY CHANGES IN ADULT RATS.

    EPA Science Inventory

    The acute neurobehavioral effects of acetylcholinesterase-inhibiting pesticides are primarily due to overstimulation of the cholinergic system. Lowered motor activity levels represent a sensitive endpoint with which to monitor functional changes in laboratory animals exposed to ...

  19. The relationship between actual motor competence and physical activity in children: mediating roles of perceived motor competence and health-related physical fitness.

    PubMed

    Khodaverdi, Zeinab; Bahram, Abbas; Stodden, David; Kazemnejad, Anoshirvan

    2016-08-01

    The purpose of this study was to investigate whether perceived motor competence and components of health-related physical fitness mediated the relationship between actual motor competence and physical activity in 8- to 9-year-old Iranian girls. A convenience sample of 352 girls (mean age = 8.7, SD = 0.3 years) participated in the study. Actual motor competence, perceived motor competence and children's physical activity were assessed using the Test of Gross Motor Development-2, the physical ability sub-scale of Marsh's Self-Description Questionnaire and Physical Activity Questionnaire for Older Children, respectively. Body mass index, the 600 yard run/walk, curl-ups, push-ups, and back-saver sit and reach tests assessed health-related physical fitness. Preacher & Hayes (2004) bootstrap method was used to assess the potential mediating effects of fitness and perceived competence on the direct relationship between actual motor competence and physical activity. Regression analyses revealed that aerobic fitness (b = .28, 95% CI = [.21, .39]), as the only fitness measure, and perceived competence (b = .16, 95% CI = [.12, .32]) were measures that mediated the relationship between actual motor competence and physical activity with the models. Development of strategies targeting motor skill acquisition, children's self-perceptions of competence and cardiorespiratory fitness should be targeted to promote girls' moderate-to-vigorous physical activity. PMID:26691581

  20. Perception and motor activity: reality is always virtual

    NASA Astrophysics Data System (ADS)

    Bridgeman, Bruce

    1999-05-01

    We differentiate a cognitive branch of the visual system from a sensorimotor branch with the Roelofs, effect, a perception that a target's position is biased in the direction opposite the offset of a surrounding frame. Previous research left the possibility that accurate motor responses to a perceptually mislocated target might be mediated by oculomotor fixation of the target. Subjects performed judging and jabbing tasks to probe cognitive and motor system representations respectively while engaging in a saccadic task that prevented fixation of the target. Three experiments with an oculomotor distractor task evaluated judging and jabbing responses to the target. Three experiments did not show a Roelofs effect in spite of the prevention of fixation on the target. Motor response did not show a Roelofs effect in spite of the prevention of fixation on the target. Further, a decision about which of two targets to jab does not result in cognitive-system information affect motor response. The Roelofs effect was presented, however, in judging trials that also involved the saccadic task.

  1. A Guide for Perceptual-Motor Training Activities.

    ERIC Educational Resources Information Center

    South Euclid - Lyndhurst City Schools, Lyndhurst, OH.

    This document has been prepared as part of a kindergarten perceptual-training program of the South Euclid-Lyndhurst City School District near Cleveland, Ohio. The guide contains information on training and procedures related to perceptual-motor learning. This information is structured primarily into 150 lesson plans, devised as 30-minute sessions…

  2. Project Success for the SLD Child, Motor-Perception Activities.

    ERIC Educational Resources Information Center

    Wayne - Carroll Public Schools, Wayne, NE.

    Presented is a curriculum guide for a perceptual motor program which was developed by Project Success (Nebraska) through a Title III grant for language learning disabled elementary level students in kindergarten through grade 3. The program is said to be arranged in a hierarchy of skills ranging from simple to complex and to be written so that the…

  3. Detection Thresholds of Falling Snow from Satellite-Borne Active and Passive Sensors

    NASA Technical Reports Server (NTRS)

    Skofronick-Jackson, Gail; Johnson, Benjamin T.; Munchak, S. Joseph

    2012-01-01

    surface of 0.25 g / cubic m and dendrite snowflakes be detected? If this information is known, we can focus retrieval efforts on detectable storms and concentrate advances on achievable results. Here, the focus is to determine thresholds of detection for falling snow for various snow conditions over land and lake surfaces. The results rely on simulated Weather Research Forecasting (WRF) simulations of falling snow cases since simulations provide all the information to determine the measurements from space and the ground truth. Sensitivity analyses were performed to better ascertain the relationships between multifrequency microwave and millimeter-wave sensor observations and the falling snow/underlying field of view. In addition, thresholds of detection for various sensor channel configurations, snow event system characteristics, snowflake particle assumptions, and surface types were studied. Results will be presented for active radar at Ku, Ka, and W-band and for passive radiometer channels from 10 to 183 GHz.

  4. Graded boosting of synaptic signals by low-threshold voltage-activated calcium conductance.

    PubMed

    Carbó Tano, Martín; Vilarchao, María Eugenia; Szczupak, Lidia

    2015-07-01

    Low-threshold voltage-activated calcium conductances (LT-VACCs) play a substantial role in shaping the electrophysiological attributes of neurites. We have investigated how these conductances affect synaptic integration in a premotor nonspiking (NS) neuron of the leech nervous system. These cells exhibit an extensive neuritic tree, do not fire Na(+)-dependent spikes, but express an LT-VACC that was sensitive to 250 μM Ni(2+) and 100 μM NNC 55-0396 (NNC). NS neurons responded to excitation of mechanosensory pressure neurons with depolarizing responses for which amplitude was a linear function of the presynaptic firing frequency. NNC decreased these synaptic responses and abolished the concomitant widespread Ca(2+) signals. Coherent with the interpretation that the LT-VACC amplified signals at the postsynaptic level, this conductance also amplified the responses of NS neurons to direct injection of sinusoidal current. Synaptic amplification thus is achieved via a positive feedback in which depolarizing signals activate an LT-VACC that, in turn, boosts these signals. The wide distribution of LT-VACC could support the active propagation of depolarizing signals, turning the complex NS neuritic tree into a relatively compact electrical compartment. PMID:25972583

  5. The use of fluorine-18 fluorodeoxyglucose positron emission tomography for imaging human motor neuronal activation in the brain

    PubMed Central

    PAHK, KISOO; PARK, KUN-WOO; PYUN, SUNG BOM; LEE, JAE SUNG; KIM, SUNGEUN; CHOE, JAE GOL

    2015-01-01

    The present study aimed to visualize human motor neuronal activation in the brain using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), and to develop an FDG-PET procedure for imaging neuronal activation. A male volunteer underwent 20 min periods of rest and motor activation, whilst being assessed using FDG-PET on two consecutive days. The motor task, which involved repetitively grasping and releasing the right hand, was performed during the initial 5 min of the activation period. Subtraction of the rest period signal from the activation PET images was performed using the subtraction ictal single-photon emission computed tomography co-registered to magnetic resonance imaging method. The subtracted image detected activation of the contralateral (left) primary motor cortex, supplementary motor area, and ipsilateral (right) cerebellum. In the present study, FDG-PET detected significantly increased motor-associated activation of the brain in a subject performing a motor task. PMID:26668604

  6. Decoding human motor activity from EEG single trials for a discrete two-dimensional cursor control

    NASA Astrophysics Data System (ADS)

    Huang, Dandan; Lin, Peter; Fei, Ding-Yu; Chen, Xuedong; Bai, Ou

    2009-08-01

    This study aims to explore whether human intentions to move or cease to move right and left hands can be decoded from spatiotemporal features in non-invasive EEG in order to control a discrete two-dimensional cursor movement for a potential multidimensional brain-computer interface (BCI). Five naïve subjects performed either sustaining or stopping a motor task with time locking to a predefined time window by using motor execution with physical movement or motor imagery. Spatial filtering, temporal filtering, feature selection and classification methods were explored. The performance of the proposed BCI was evaluated by both offline classification and online two-dimensional cursor control. Event-related desynchronization (ERD) and post-movement event-related synchronization (ERS) were observed on the contralateral hemisphere to the hand moved for both motor execution and motor imagery. Feature analysis showed that EEG beta band activity in the contralateral hemisphere over the motor cortex provided the best detection of either sustained or ceased movement of the right or left hand. The offline classification of four motor tasks (sustain or cease to move right or left hand) provided 10-fold cross-validation accuracy as high as 88% for motor execution and 73% for motor imagery. The subjects participating in experiments with physical movement were able to complete the online game with motor execution at an average accuracy of 85.5 ± 4.65%; the subjects participating in motor imagery study also completed the game successfully. The proposed BCI provides a new practical multidimensional method by noninvasive EEG signal associated with human natural behavior, which does not need long-term training.

  7. Motor and non-motor circuitry activation induced by subthalamic nucleus deep brain stimulation (STN DBS) in Parkinson’s disease patients: Intraoperative fMRI for DBS

    PubMed Central

    Knight, Emily J.; Testini, Paola; Min, Hoon-Ki; Gibson, William S.; Gorny, Krzysztof R.; Favazza, Christopher P.; Felmlee, Joel P.; Kim, Inyong; Welker, Kirk M.; Clayton, Daniel A.; Klassen, Bryan T.; Chang, Su-youne; Lee, Kendall H.

    2015-01-01

    Objective To test the hypothesis suggested by previous studies that subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with PD would affect the activity of both motor and non-motor networks, we applied intraoperative fMRI to patients receiving DBS. Patients and Methods Ten patients receiving STN DBS for PD underwent intraoperative 1.5T fMRI during high frequency stimulation delivered via an external pulse generator. The study was conducted between the dates of January 1, 2013 and September 30, 2014. Results We observed blood oxygen level dependent (BOLD) signal changes (FDR<.001) in the motor circuitry, including primary motor, premotor, and supplementary motor cortices, thalamus, pedunculopontine nucleus (PPN), and cerebellum, as well as in the limbic circuitry, including cingulate and insular cortices. Activation of the motor network was observed also after applying a Bonferroni correction (p<.001) to our dataset, suggesting that, across subjects, BOLD changes in the motor circuitry are more consistent compared to those occurring in the non-motor network. Conclusions These findings support the modulatory role of STN DBS on the activity of motor and non-motor networks, and suggest complex mechanisms at the basis of the efficacy of this treatment modality. Furthermore, these results suggest that, across subjects, BOLD changes in the motor circuitry are more consistent compared to those occurring in the non-motor network. With further studies combining the use of real time intraoperative fMRI with clinical outcomes in patients treated with DBS, functional imaging techniques have the potential not only to elucidate the mechanisms of DBS functioning, but also to guide and assist in the surgical treatment of patients affected by movement and neuropsychiatric disorders. PMID:26046412

  8. Opposite-polarity motors activate one another to trigger cargo transport in live cells.

    PubMed

    Ally, Shabeen; Larson, Adam G; Barlan, Kari; Rice, Sarah E; Gelfand, Vladimir I

    2009-12-28

    Intracellular transport is typically bidirectional, consisting of a series of back and forth movements. Kinesin-1 and cytoplasmic dynein require each other for bidirectional transport of intracellular cargo along microtubules; i.e., inhibition or depletion of kinesin-1 abolishes dynein-driven cargo transport and vice versa. Using Drosophila melanogaster S2 cells, we demonstrate that replacement of endogenous kinesin-1 or dynein with an unrelated, peroxisome-targeted motor of the same directionality activates peroxisome transport in the opposite direction. However, motility-deficient versions of motors, which retain the ability to bind microtubules and hydrolyze adenosine triphosphate, do not activate peroxisome motility. Thus, any pair of opposite-polarity motors, provided they move along microtubules, can activate one another. These results demonstrate that mechanical interactions between opposite-polarity motors are necessary and sufficient for bidirectional organelle transport in live cells. PMID:20038680

  9. Opposite-polarity motors activate one another to trigger cargo transport in live cells

    PubMed Central

    Ally, Shabeen; Larson, Adam G.; Barlan, Kari; Rice, Sarah E.

    2009-01-01

    Intracellular transport is typically bidirectional, consisting of a series of back and forth movements. Kinesin-1 and cytoplasmic dynein require each other for bidirectional transport of intracellular cargo along microtubules; i.e., inhibition or depletion of kinesin-1 abolishes dynein-driven cargo transport and vice versa. Using Drosophila melanogaster S2 cells, we demonstrate that replacement of endogenous kinesin-1 or dynein with an unrelated, peroxisome-targeted motor of the same directionality activates peroxisome transport in the opposite direction. However, motility-deficient versions of motors, which retain the ability to bind microtubules and hydrolyze adenosine triphosphate, do not activate peroxisome motility. Thus, any pair of opposite-polarity motors, provided they move along microtubules, can activate one another. These results demonstrate that mechanical interactions between opposite-polarity motors are necessary and sufficient for bidirectional organelle transport in live cells. PMID:20038680

  10. Early motor skill competence as a mediator of child and adult physical activity

    PubMed Central

    Loprinzi, Paul D.; Davis, Robert E.; Fu, Yang-Chieh

    2015-01-01

    Objective: In order to effectively promote physical activity (PA) during childhood, and across the lifespan, a better understanding of the role of early motor skill development on child and adult PA is needed. Methods: Here, we propose a conceptual model delineating the hypothesized influence of motor skill development on child and adult PA, while providing an overview of the current empirical research related to this model. Results: There is consistent and emerging evidence showing that adequate motor skill competence, particularly locomotor and gross motor skills, is associated with increased PA levels during the preschool, child, and adolescent years, with early motor skill development also influencing enjoyment of PA as well as long-term PA and motor skill performance. The physical education setting appears to be a well-suited environment for motor skill development. Conclusion: Employing appropriate strategies to target motor skill development across the childhood years is of paramount interest in helping shape children's PA behavior, their experiences related to PA, as well as maintain their PA. PMID:26844157

  11. Brain Activation Patterns Characterizing Different Phases of Motor Action: Execution, Choice and Ideation.

    PubMed

    Gardini, Simona; Venneri, Annalena; McGeown, William Jonathan; Toraci, Cristian; Nocetti, Luca; Porro, Carlo Adolfo; Caffarra, Paolo

    2016-09-01

    Motor behaviour is controlled by a large set of interacting neural structures, subserving the different components involved in hierarchical motor processes. Few studies have investigated the neural substrate of higher-order motor ideation, i.e. the mental operation of conceiving a movement. The aim of this functional magnetic resonance imaging study was to segregate the neural structures involved in motor ideation from those involved in movement choice and execution. An index finger movement paradigm was adopted, including three different conditions: performing a pre-specified movement, choosing and executing a movement and ideating a movement of choice. The tasks involved either the right or left hand, in separate runs. Neuroimaging results were obtained by comparing the different experimental conditions and computing conjunction maps of the right and left hands for each contrast. Pre-specified movement execution was supported by bilateral fronto-parietal motor regions, the cerebellum and putamen. Choosing and executing finger movement involved mainly left fronto-temporal areas and the anterior cingulate. Motor ideation activated almost exclusively left hemisphere regions, including the inferior, middle and superior frontal regions, middle temporal and middle occipital gyri. These findings show that motor ideation is controlled by a cortical network mainly involved in abstract thinking, cognitive and motor control, semantic and visual imagery processes. PMID:27072014

  12. Motor Neuron-Specific Overexpression of the Presynaptic Choline Transporter: Impact on Motor Endurance and Evoked Muscle Activity

    PubMed Central

    Lund, David; Ruggiero, Alicia M.; Ferguson, Shawn M.; Wright, Jane; English, Brett A.; Reisz, Peter A.; Whitaker, Sarah M.; Peltier, Amanda C.; Blakely, Randy D.

    2010-01-01

    The presynaptic, hemicholinium-3 sensitive, high-affinity choline transporter (CHT) supplies choline for acetylcholine (ACh) synthesis. In mice, a homozygous deletion of CHT (CHT−/−) leads to premature cessation of spontaneous or evoked neuromuscular signaling and is associated with perinatal cyanosis and lethality within 1 hr. Heterozygous (CHT+/−) mice exhibit diminished brain ACh levels and demonstrate an inability to sustain vigorous motor activity. We sought to explore the contribution of CHT gene dosage to motor function in greater detail using transgenic mice where CHT is expressed under control of the motor neuron promoter Hb9 (Hb9:CHT). On a CHT−/− background, the Hb9:CHT transgene conferred mice with the ability to move and breath for a postnatal period of ~24 hrs, thus increasing survival. Conversely, Hb9:CHT expression on a wild-type background (CHT+/+;Hb9:CHT) leads to an increased capacity for treadmill running compared to wild-type littermates. Analysis of the stimulated compound muscle action potential (CMAP) in these animals under basal conditions established that CHT+/+;Hb9:CHT mice display an unexpected, bidirectional change, producing either elevated or reduced CMAP amplitude, relative to CHT+/+ animals. To examine whether these two groups arise from underlying changes in synaptic properties, we used high-frequency stimulation of motor axons to assess CMAP recovery kinetics. Although CHT+/+;Hb9:CHT mice in the two groups display an equivalent, time-dependent reduction in CMAP amplitude, animals with a higher basal CMAP amplitude demonstrate a significantly enhanced rate of recovery. To explain our findings, we propose a model whereby CHT support for neuromuscular signaling involves contributions to ACh synthesis as well as cholinergic synaptic vesicle availability. PMID:20888396

  13. Transcranial direct current stimulation over the supplementary motor area modulates the preparatory activation level in the human motor system

    PubMed Central

    Carlsen, Anthony N.; Eagles, Jeremy S.; MacKinnon, Colum D.

    2016-01-01

    Transcranial direct current stimulation (tDCS) is a non-invasive stimulation method that can induce transient polarity-specific neuroplastic changes in cortical excitability lasting up to 1 h post-stimulation. While excitability changes with stimulation over the primary motor cortex have been well documented, the functional effects of stimulation over premotor regions are less well understood. In the present experiment, we tested how cathodal and anodal tDCS applied over the region of the supplementary motor area (SMA) affected preparation and initiation of a voluntary movement. Participants performed a simple reaction time (RT) task requiring a targeted wrist-extension in response to a go-signal. In 20% of RT trials a startling acoustic stimulus (SAS) was presented 500 ms prior to the “go” signal in order to probe the state of motor preparation. Following the application of cathodal, anodal, or sham tDCS (separate days) over SMA for 10 min, participants performed blocks of RT trials at 10 min intervals. While sham stimulation did not affect RT or incidence of early release by the SAS, cathodal tDCS led to a significant slowing of RT that peaked 10 min after the end of stimulation and was associated with a marked decrease in the incidence of movement release by the SAS. In contrast, anodal tDCS resulted in faster RTs, but the incidence of release was unchanged. These results are consistent with the SMA playing a role in the pre-planning of movements and that modulating its activity with tDCS can lead to polarity-specific changes in motor behavior. PMID:25446764

  14. Predictive motor control of sensory dynamics in auditory active sensing.

    PubMed

    Morillon, Benjamin; Hackett, Troy A; Kajikawa, Yoshinao; Schroeder, Charles E

    2015-04-01

    Neuronal oscillations present potential physiological substrates for brain operations that require temporal prediction. We review this idea in the context of auditory perception. Using speech as an exemplar, we illustrate how hierarchically organized oscillations can be used to parse and encode complex input streams. We then consider the motor system as a major source of rhythms (temporal priors) in auditory processing, that act in concert with attention to sharpen sensory representations and link them across areas. We discuss the circuits that could mediate this audio-motor interaction, notably the potential role of the somatosensory system. Finally, we reposition temporal predictions in the context of internal models, discussing how they interact with feature-based or spatial predictions. We argue that complementary predictions interact synergistically according to the organizational principles of each sensory system, forming multidimensional filters crucial to perception. PMID:25594376

  15. Physical activity and obesity mediate the association between childhood motor function and adolescents' academic achievement.

    PubMed

    Kantomaa, Marko T; Stamatakis, Emmanuel; Kankaanpää, Anna; Kaakinen, Marika; Rodriguez, Alina; Taanila, Anja; Ahonen, Timo; Järvelin, Marjo-Riitta; Tammelin, Tuija

    2013-01-29

    The global epidemic of obesity and physical inactivity may have detrimental implications for young people's cognitive function and academic achievement. This prospective study investigated whether childhood motor function predicts later academic achievement via physical activity, fitness, and obesity. The study sample included 8,061 children from the Northern Finland Birth Cohort 1986, which contains data about parent-reported motor function at age 8 y and self-reported physical activity, predicted cardiorespiratory fitness (cycle ergometer test), obesity (body weight and height), and academic achievement (grades) at age 16 y. Structural equation models with unstandardized (B) and standardized (β) coefficients were used to test whether, and to what extent, physical activity, cardiorespiratory fitness, and obesity at age 16 mediated the association between childhood motor function and adolescents' academic achievement. Physical activity was associated with a higher grade-point average, and obesity was associated with a lower grade-point average in adolescence. Furthermore, compromised motor function in childhood had a negative indirect effect on adolescents' academic achievement via physical inactivity (B = -0.023, 95% confidence interval = -0.031, -0.015) and obesity (B = -0.025, 95% confidence interval = -0.039, -0.011), but not via cardiorespiratory fitness. These results suggest that physical activity and obesity may mediate the association between childhood motor function and adolescents' academic achievement. Compromised motor function in childhood may represent an important factor driving the effects of obesity and physical inactivity on academic underachievement. PMID:23277558

  16. Neural Activation during Anticipation of Near Pain-Threshold Stimulation among the Pain-Fearful

    PubMed Central

    Yang, Zhou; Jackson, Todd; Huang, Chengzhi

    2016-01-01

    Fear of pain (FOP) can increase risk for chronic pain and disability but little is known about corresponding neural responses in anticipation of potential pain. In this study, more (10 women, 6 men) and less (7 women, 6 men) pain-fearful groups underwent whole-brain functional magnetic resonance imaging (fMRI) during anticipation of near pain-threshold stimulation. Groups did not differ in the proportion of stimuli judged to be painful but pain-fearful participants reported significantly more state fear prior to stimulus exposure. Within the entire sample, stronger activation was found in several pain perception regions (e.g., bilateral insula, midcingulate cortex (MCC), thalamus, superior frontal gyrus) and visual areas linked to decoding stimulus valences (inferior orbital cortex) during anticipation of “painful” stimuli. Between groups and correlation analyses indicated pain-fearful participants experienced comparatively more activity in regions implicated in evaluating potential threats and processing negative emotions during anticipation (i.e., MCC, mid occipital cortex, superior temporal pole), though group differences were not apparent in most so-called “pain matrix” regions. In sum, trait- and task-based FOP is associated with enhanced responsiveness in regions involved in threat processing and negative affect during anticipation of potentially painful stimulation. PMID:27489536

  17. Group planarian sudden mortality: Is the threshold around global geomagnetic activity ≥K6?

    PubMed Central

    Murugan, Nirosha J; Karbowski, Lukasz M; Mekers, William Ft; Persinger, Michael A

    2015-01-01

    Sudden deaths in groups of animals have been observed by field and laboratory biologists. We have measured mortalities in large group-housed planarian during the infrequent periods of very intense geomagnetic activity. In 13 separate episodes over the last 5 y we have observed the sudden death in our laboratory of hundreds of planarian if their density was about 1 worm per cc and the global geomagnetic activity was K≥6 the day before or the day of the observation of the mortality. Such mortality never occurred in other conditions or days. Both estimates of the "magnetic moment" of a planarian in magnetic fields above this threshold of sustained magnetic flux density as well as the magnetic energy within the planarian volume predict values that could affect phenomenon associated with the total numbers of pH-dependent charges within each worm. These conditions could affect the Levin-Burr bioelectrical signals and networks that affect patterning information and sustainability in whole living systems. The establishment of a central reservoir for the report of these transient events might allow Life Scientists to more fully appreciate the impact of these pervasive global stimuli upon dense groups of animals. PMID:27066174

  18. Neural Activation during Anticipation of Near Pain-Threshold Stimulation among the Pain-Fearful.

    PubMed

    Yang, Zhou; Jackson, Todd; Huang, Chengzhi

    2016-01-01

    Fear of pain (FOP) can increase risk for chronic pain and disability but little is known about corresponding neural responses in anticipation of potential pain. In this study, more (10 women, 6 men) and less (7 women, 6 men) pain-fearful groups underwent whole-brain functional magnetic resonance imaging (fMRI) during anticipation of near pain-threshold stimulation. Groups did not differ in the proportion of stimuli judged to be painful but pain-fearful participants reported significantly more state fear prior to stimulus exposure. Within the entire sample, stronger activation was found in several pain perception regions (e.g., bilateral insula, midcingulate cortex (MCC), thalamus, superior frontal gyrus) and visual areas linked to decoding stimulus valences (inferior orbital cortex) during anticipation of "painful" stimuli. Between groups and correlation analyses indicated pain-fearful participants experienced comparatively more activity in regions implicated in evaluating potential threats and processing negative emotions during anticipation (i.e., MCC, mid occipital cortex, superior temporal pole), though group differences were not apparent in most so-called "pain matrix" regions. In sum, trait- and task-based FOP is associated with enhanced responsiveness in regions involved in threat processing and negative affect during anticipation of potentially painful stimulation. PMID:27489536

  19. A Field-Based Testing Protocol for Assessing Gross Motor Skills in Preschool Children: The Children's Activity and Movement in Preschool Study Motor Skills Protocol

    ERIC Educational Resources Information Center

    Williams, Harriet G.; Pfeiffer, Karin A.; Dowda, Marsha; Jeter, Chevy; Jones, Shaverra; Pate, Russell R.

    2009-01-01

    The purpose of this study was to develop a valid and reliable tool for use in assessing motor skills in preschool children in field-based settings. The development of the Children's Activity and Movement in Preschool Study Motor Skills Protocol included evidence of its reliability and validity for use in field-based environments as part of large…

  20. Ankle Accelerometry for Assessing Physical Activity among Adolescent Girls: Threshold Determination, Validity, Reliability, and Feasibility

    ERIC Educational Resources Information Center

    Hager, Erin R.; Treuth, Margarita S.; Gormely, Candice; Epps, LaShawna; Snitker, Soren; Black, Maureen M.

    2015-01-01

    Purpose: Ankle accelerometry allows for 24-hr data collection and improves data volume/integrity versus hip accelerometry. Using Actical ankle accelerometry, the purpose of this study was to (a) develop sensitive/specific thresholds, (b) examine validity/reliability, (c) compare new thresholds with those of the manufacturer, and (d) examine…

  1. MKP-1 antagonizes C/EBP β activity and lowers the apoptotic threshold after ischemic injury

    PubMed Central

    Rininger, A; Dejesus, C; Totten, A; Wayland, A; Halterman, M W

    2012-01-01

    The dual specificity phosphatase MAPK phosphatase-1 (MKP-1) feeds back on MAP kinase signaling to regulate metabolic, inflammatory and survival responses. MKP-1 is widely expressed in the central nervous system (CNS) and induced after ischemic stress, although its function in these contexts remains unclear. Here we report that MKP-1 activated several cell death factors, including BCL2 and adenovirus E1B 19 kDa interacting protein 3, and caspases 3 and 12 culminating in apoptotic cell death in vitro. MKP-1 also exerted inhibitory effects on the bZIP transcription factor CCAAT/enhancer-binding protein (C/EBPβ), previously shown to have neuroprotective properties. These effects included reduced expression of the full-length C/EBPβ variant and hypo-phosphorylation at the MEK-ERK1/2-sensitive Thr188 site. Notably, enforced expression C/EBPβ rescued cells from MKP-1-induced toxicity. Studies performed in knock-out mice indicate that the MKP-1 activity is required to exclude C/EBPβ from the nucleus basally, and that MKP-1 antagonizes C/EBPβ expression after global forebrain ischemia, particularly within the vulnerable CA1 sector of the hippocampus. Overall, MKP-1 appears to lower the cellular apoptotic threshold by inhibiting C/EBPβ and enhancing both BH3 protein expression and cellular caspase activity. Thus, although manipulation of the MKP-1-C/EBPβ axis could have therapeutic value in ischemic disorders, our observations using MKP-1 catalytic mutants suggest that approaches geared towards inhibiting MKP-1's phosphatase activity alone may be ineffective. PMID:22522596

  2. Activation of the motor cortex during phasic rapid eye movement sleep.

    PubMed

    De Carli, Fabrizio; Proserpio, Paola; Morrone, Elisa; Sartori, Ivana; Ferrara, Michele; Gibbs, Steve Alex; De Gennaro, Luigi; Lo Russo, Giorgio; Nobili, Lino

    2016-02-01

    When dreaming during rapid eye movement (REM) sleep, we can perform complex motor behaviors while remaining motionless. How the motor cortex behaves during this state remains unknown. Here, using intracerebral electrodes sampling the human motor cortex in pharmacoresistant epileptic patients, we report a pattern of electroencephalographic activation during REM sleep similar to that observed during the performance of a voluntary movement during wakefulness. This pattern is present during phasic REM sleep but not during tonic REM sleep, the latter resembling relaxed wakefulness. This finding may help clarify certain phenomenological aspects observed in REM sleep behavior disorder. PMID:26575212

  3. Context Modulates the Expression of Conditioned Motor Sensitization, Cellular Activation, and Synaptophysin Immunoreactivity

    PubMed Central

    Rademacher, David J.; Celeste Napier, T.; Meredith, Gloria E.

    2007-01-01

    We tested the hypothesis that amphetamine- (AMPH) induced conditioned motor sensitization is accompanied by cellular activation (measured by Fos immunoreactivity) and synaptophysin immunoreactivity in reward-related brain areas. Forty-eight rats were tested for conditioned motor sensitization using a conditioning paradigm that was performed in a three-chambered apparatus. Rats underwent two drug pairings with 1.0 mg/kg AMPH in one outer chamber and, on alternate days, were paired with saline in the other. On the fifth day, relative to the first AMPH treatment, AMPH administration increased motor activity in the AMPH-paired context but not in the saline-paired context. Relative to the first saline treatment, saline on the fifth day produced a conditioned increase in motor activity when given in the chamber previously paired with AMPH, and saline given in the saline-paired context produced a conditioned decrease in motor activity. AMPH administered in the AMPH-paired context increased the density of both Fos and synaptophysin immunoreactivity in the dentate gyrus, cornu ammonis (CA)1, CA3, basolateral amygdala, and dorsolateral striatum. This pairing between context and drug increased Fos but not synaptophysin immunoreactivity in the nucleus accumbens core and shell. Saline administered in the AMPH-paired context increased the density of Fos immunoreactivity in the basolateral amygdala and nucleus accumbens core. These data indicate that the basolateral amygdala-nucleus accumbens core pathway is necessary for the context-elicited conditioned motor responses, while the hippocampus encodes the spatial context. PMID:17970739

  4. Cytoskeletal motor-driven active self-assembly in in vitro systems.

    PubMed

    Lam, A T; VanDelinder, V; Kabir, A M R; Hess, H; Bachand, G D; Kakugo, A

    2016-01-28

    Molecular motor-driven self-assembly has been an active area of soft matter research for the past decade. Because molecular motors transform chemical energy into mechanical work, systems which employ molecular motors to drive self-assembly processes are able to overcome kinetic and thermodynamic limits on assembly time, size, complexity, and structure. Here, we review the progress in elucidating and demonstrating the rules and capabilities of motor-driven active self-assembly. We focus on the types of structures created and the degree of control realized over these structures, and discuss the next steps necessary to achieve the full potential of this assembly mode which complements robotic manipulation and passive self-assembly. PMID:26576824

  5. Chapter 6: Children's Environmental Access in Relation to Motor Competence, Physical Activity, and Fitness

    ERIC Educational Resources Information Center

    Erwin, Heather E.; Woods, Amelia Mays; Woods, Martha K.; Castelli, Darla M.

    2007-01-01

    The purpose of this study was to examine levels of physical activity engagement, motor competence, and physical fitness as related to child access to physical activity facilities in the home and school environments. The present investigation attempts to further efforts to examine the relationship between physical activity levels and access.…

  6. Motor Performance of Women as a Function of Age and Physical Activity Level.

    ERIC Educational Resources Information Center

    Rikli, Roberta; Busch, Sharman

    Two studies compared motor skills of women in terms of the influence of age and activity level. In the first study, simple and choice reaction time, balance, flexibility, and grip strength of older active women were compared with that of older inactive women, and active and inactive younger women. Except for grip strength, scores of older active…

  7. Get Kids Moving: Simple Activities To Build Gross-Motor Skills.

    ERIC Educational Resources Information Center

    Texas Child Care, 2003

    2003-01-01

    Highlights the importance of activities to build gross motor skills and provides hints for encouraging such activities. Specific areas of activities presented are: (1) running and jumping; (2) music games; (3) action games; (4) races; (5) bed sheets or parachutes; (6) hula hoops; (7) balls; (8) batting; (9) balance; and (10) creative movement. (SD)

  8. Origin of facilitation of motor-evoked potentials after paired magnetic stimulation: direct recording of epidural activity in conscious humans.

    PubMed

    Di Lazzaro, V; Pilato, F; Oliviero, A; Dileone, M; Saturno, E; Mazzone, P; Insola, A; Profice, P; Ranieri, F; Capone, F; Tonali, P A; Rothwell, J C

    2006-10-01

    A magnetic transcranial conditioning stimulus given over the motor cortex at intensities below active threshold for obtaining motor-evoked potentials (MEPs) facilitates EMG responses evoked at rest in hand muscles by a suprathreshold magnetic stimulus given 10-25 ms later. This is known as intracortical facilitation (ICF). We recorded descending volleys produced by single and paired magnetic motor cortex stimulation through high cervical epidural electrodes implanted for pain relief in six conscious patients. At interstimulus intervals (ISIs) of 10 and 15 ms, although MEP was facilitated, there was no change in the amplitude or number of descending volleys. An additional I wave sometimes was observed at 25 ms ISI. In one subject, we also evaluated the effects of reversing the direction of the induced current in the brain. At 10 ms ISI, the facilitation of the MEPs disappeared and was replaced by slight suppression; at 2 ms ISI, there was a pronounced facilitation of epidural volleys. Subsequent experiments on healthy subjects showed that a conditioning stimulus capable of producing ICF of MEPs had no effect on the EMG response evoked by transmastoidal electrical stimulation of corticospinal tract. We conclude that ICF occurs because either 1) the conditioning stimulus has a (thus far undetected) effect on spinal cord excitability that increases its response to the same amplitude test volley or 2) that it can alter the composition (but not the amplitude) of the descending volleys set up by the test stimulus such that a larger proportion of the activity is destined for the target muscle. PMID:16760345

  9. Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

    PubMed Central

    Li, Hongfei; Chen, Ji-Hong; Yang, Zixian; Huang, Min; Yu, Yuanjie; Tan, Shiyun; Luo, Hesheng; Huizinga, Jan D

    2016-01-01

    Background/Aims Neurotensin is a gut-brain peptide with both inhibitory and excitatory actions on the colonic musculature; our objective was to understand the implications of this for motor patterns occurring in the intact colon of the rat. Methods The effects of neurotensin with concentrations ranging from 0.1–100 nM were studied in the intact rat colon in vitro, by investigating spatio-temporal maps created from video recordings of colonic motility before and after neurotensin. Results Low concentration of neurotensin (0.1–1 nM) inhibited propagating long distance contractions and rhythmic propagating motor complexes; in its place a slow propagating rhythmic segmental motor pattern developed. The neurotensin receptor 1 antagonist SR-48692 prevented the development of the segmental motor pattern. Higher concentrations of neurotensin (10 nM and 100 nM) were capable of restoring long distance contraction activity and inhibiting the segmental activity. The slow propagating segmental contraction showed a rhythmic contraction—relaxation cycle at the slow wave frequency originating from the interstitial cells of Cajal associated with the myenteric plexus pacemaker. High concentrations given without prior additions of low concentrations did not evoke the segmental motor pattern. These actions occurred when neurotensin was given in the bath solution or intraluminally. The segmental motor pattern evoked by neurotensin was inhibited by the neural conduction blocker lidocaine. Conclusions Neurotensin (0.1–1 nM) inhibits the dominant propulsive motor patterns of the colon and a distinct motor pattern of rhythmic slow propagating segmental contractions develops. This motor pattern has the hallmarks of haustral boundary contractions. PMID:26882114

  10. Effectiveness of a low-threshold physical activity intervention in residential aged care – results of a randomized controlled trial

    PubMed Central

    Cichocki, Martin; Quehenberger, Viktoria; Zeiler, Michael; Adamcik, Tanja; Manousek, Matthias; Stamm, Tanja; Krajic, Karl

    2015-01-01

    Purpose Research on effectiveness of low-threshold mobility interventions that are viable for users of residential aged care is scarce. Low-threshold is defined as keeping demands on organizations (staff skills, costs) and participants (health status, discipline) rather low. The study explored the effectiveness of a multi-faceted, low-threshold physical activity program in three residential aged-care facilities in Austria. Main goals were enhancement of mobility by conducting a multi-faceted training program to foster occupational performance and thus improve different aspects of health-related quality of life (QoL). Participants and methods The program consisted of a weekly session of 60 minutes over a period of 20 weeks. A standardized assessment of mobility status and health-related QoL was applied before and after the intervention. A total of 222 of 276 participants completed the randomized controlled trial study (intervention group n=104, control group n=118; average age 84 years, 88% female). Results Subjective health status (EuroQoL-5 dimensions: P=0.001, d=0.36) improved significantly in the intervention group, and there were also positive trends in occupational performance (Canadian Occupational Performance Measure). No clear effects were found concerning the functional and cognitive measures applied. Conclusion Thus, the low-threshold approach turned out to be effective primarily on subjective health-related QoL. This outcome could be a useful asset for organizations offering low-threshold physical activity interventions. PMID:26056438

  11. Making sense(s) in dementia: a multisensory and motor-based group activity program.

    PubMed

    Cruz, Joana; Marques, Alda; Barbosa, Ana; Figueiredo, Daniela; Sousa, Liliana X

    2013-03-01

    Lack of engagement in meaningful activities is associated with poor quality of life in dementia; thus, the development of these activities has been recommended. This pilot study aimed to develop a multisensory and motor-based group activity program for residents with dementia and assess its impact on residents' behavior. The program was designed using a multisensory and motor-based approach in sixteen 45-minute weekly sessions tailored to residents' characteristics. Four residents with advanced dementia participated in the program. The frequency and duration of the residents' behavior were assessed using video recordings. All residents participated in the proposed activities, although they were more participative and communicative in some sessions than in others. Group activity programs based on multisensory and motor stimulation can be a promising approach for people with advanced dementia; however, further research is needed. This study may serve as reference to the implementation of future programs aiming to increase person-centeredness of the care provided. PMID:23307794

  12. BDNF heightens the sensitivity of motor neurons to excitotoxic insults through activation of TrkB

    NASA Technical Reports Server (NTRS)

    Hu, Peter; Kalb, Robert G.; Walton, K. D. (Principal Investigator)

    2003-01-01

    The survival promoting and neuroprotective actions of brain-derived neurotrophic factor (BDNF) are well known but under certain circumstances this growth factor can also exacerbate excitotoxic insults to neurons. Prior exploration of the receptor through which BDNF exerts this action on motor neurons deflects attention away from p75. Here we investigated the possibility that BDNF acts through the receptor tyrosine kinase, TrkB, to confer on motor neurons sensitivity to excitotoxic challenge. We blocked BDNF activation of TrkB using a dominant negative TrkB mutant or a TrkB function blocking antibody, and found that this protected motor neurons against excitotoxic insult in cultures of mixed spinal cord neurons. Addition of a function blocking antibody to BDNF to mixed spinal cord neuron cultures is also neuroprotective indicating that endogenously produced BDNF participates in vulnerability to excitotoxicity. We next examined the intracellular signaling cascades that are engaged upon TrkB activation. Previously we found that inhibition of the phosphatidylinositide-3'-kinase (PI3'K) pathway blocks BDNF-induced excitotoxic sensitivity. Here we show that expression of a constitutively active catalytic subunit of PI3'K, p110, confers excitotoxic sensitivity (ES) upon motor neurons not incubated with BDNF. Parallel studies with purified motor neurons confirm that these events are likely to be occuring specifically within motor neurons. The abrogation of BDNF's capacity to accentuate excitotoxic insults may make it a more attractive neuroprotective agent.

  13. Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground.

    PubMed

    Tortella, Patrizia; Haga, Monika; Loras, Håvard; Sigmundsson, Hermundur; Fumagalli, Guido

    2016-01-01

    This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s) appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens. PMID:27462985

  14. Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground

    PubMed Central

    Tortella, Patrizia; Haga, Monika; Loras, Håvard

    2016-01-01

    This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s) appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens. PMID:27462985

  15. Covert imitation of transitive actions activates effector-independent motor representations affecting "motor" knowledge of target-object properties.

    PubMed

    Campione, Giovanna Cristina; Gentilucci, Maurizio

    2010-03-01

    The present study aimed at determining whether, and in what conditions, covert imitation of different manual grasps of the same object influences estimation of those object properties whose variations afford those different grasp interactions. Participants matched the size of spheres after observation of the same spheres being grasped using both a power and a precision grasp: these actions are used preferentially to grasp large and small objects, respectively. The type of matching varied across four experiments. In experiment 1, participants matched the object size by opening their thumb and index finger; in experiment 2, they abducted their index and middle fingers as in a finger opening of a cutting pantomime, and in experiment 3, they opened their mouth. In experiment 4, the sphere size was reproduced on a PC monitor by moving the mouse forward/backward. Grasp observation affected matching in experiments 1 and 3. Kinematics analysis showed overestimation after observation of a power grasp as compared to a precision grasp. The data are interpreted as a consequence of covert imitation of the observed hand kinematics, which varied congruently with the object sizes potentially activating that type-of-grasp. This affected estimation of object size. Covert imitation was favored by the types of matching requiring motor patterns related to grasp movements independently of the effector used. This finding supports the existence of motor commands to the hand as well as to the mouth, activated when the same potential goal guides the movements of both these effectors. PMID:19850083

  16. Effects of caffeine on locomotor activity of horses: determination of the no-effect threshold.

    PubMed

    Queiroz-Neto, A; Zamur, G; Carregaro, A B; Mataqueiro, M I; Salvadori, M C; Azevedo, C P; Harkins, J D; Tobin, T

    2001-01-01

    Caffeine is the legal stimulant consumed most extensively by the human world population and may be found eventually in the urine and/or blood of race horses. The fact that caffeine is in foods led us to determine the highest no-effect dose (HNED) of caffeine on the spontaneous locomotor activity of horses and then to quantify this substance in urine until it disappeared. We built two behavioural stalls equipped with juxtaposed photoelectric sensors that emit infrared beams that divide the stall into nine sectors in a 'tic-tac-toe' fashion. Each time a beam was interrupted by a leg of the horse, a pulse was generated; the pulses were counted at 5-min intervals and stored by a microcomputer. Environmental effects were minimized by installing exhaust fans producing white noise that obscured outside sounds. One-way observation windows prevented the animals from seeing outside. The sensors were turned on 45 min before drug administration (saline control or caffeine). The animals were observed for up to 8 h after i.v. administration of 2.0, 2.5, 3.0 or 5.0 mg caffeine kg(-1). The HNED of caffeine for stimulation of the spontaneous locomotor activity of horses was 2.0 mg kg(-1). The quantification of caffeine in urine and plasma samples was done by gradient HPLC with UV detection. The no-effect threshold should not be greater than 2.0 microg caffeine ml(-1) plasma or 5.0 microg caffeine ml(-1) urine. PMID:11404835

  17. Motor System Activation Predicts Goal Imitation in 7-Month-Old Infants.

    PubMed

    Filippi, Courtney A; Cannon, Erin N; Fox, Nathan A; Thorpe, Samuel G; Ferrari, Pier F; Woodward, Amanda L

    2016-05-01

    The current study harnessed the variability in infants' neural and behavioral responses as a novel method for evaluating the potential relations between motor system activation and social behavior. We used electroencephalography (EEG) to record neural activity as 7-month-old infants observed and responded to the actions of an experimenter. To determine whether motor system activation predicted subsequent imitation behavior, we assessed event-related desynchronization (ERD) at central sites during action observation as a function of subsequent behavior. Greater mu desynchronization over central sites was observed when infants subsequently reproduced the experimenter's goal than when they did not reproduce the goal and instead selected the nongoal object. We also found that mu desynchronization during action execution predicted the infants' later propensity to reproduce the experimenter's goal-directed behavior. These results provide the first evidence that motor system activation predicts the imitation of other individuals' goals during infancy. PMID:27071750

  18. Motor units in incomplete spinal cord injury: electrical activity, contractile properties and the effects of biofeedback.

    PubMed

    Stein, R B; Brucker, B S; Ayyar, D R

    1990-10-01

    The electrical and contractile properties of hand muscles in a selected population of quadriplegic subjects were studied intensively before and after EMG biofeedback. Spontaneously active motor units and units that could only be slowly and weakly activated were observed in these subjects, in addition to units that were voluntarily activated normally. This suggests a considerable overlap of surviving motor neurons to a single muscle that are below, near or above the level of a lesion. Despite the common occurrence of polyphasic potentials and other signs of neuromuscular reinnervation, the average twitch tension of single motor units in hand muscles of quadriplegic subjects was not significantly different from that in control subjects. Nor did it increase after biofeedback training that typically increased the peak surface EMG by a factor of 2-5 times. The percentage of spontaneously active units was also constant. The surface EMG may be increased during biofeedback by using higher firing rates in motor units that can already be activated, rather than by recruiting previously unavailable motor units. PMID:2266370

  19. Enhanced activation of motor execution networks using action observation combined with imagination of lower limb movements.

    PubMed

    Villiger, Michael; Estévez, Natalia; Hepp-Reymond, Marie-Claude; Kiper, Daniel; Kollias, Spyros S; Eng, Kynan; Hotz-Boendermaker, Sabina

    2013-01-01

    The combination of first-person observation and motor imagery, i.e. first-person observation of limbs with online motor imagination, is commonly used in interactive 3D computer gaming and in some movie scenes. These scenarios are designed to induce a cognitive process in which a subject imagines himself/herself acting as the agent in the displayed movement situation. Despite the ubiquity of this type of interaction and its therapeutic potential, its relationship to passive observation and imitation during observation has not been directly studied using an interactive paradigm. In the present study we show activation resulting from observation, coupled with online imagination and with online imitation of a goal-directed lower limb movement using functional MRI (fMRI) in a mixed block/event-related design. Healthy volunteers viewed a video (first-person perspective) of a foot kicking a ball. They were instructed to observe-only the action (O), observe and simultaneously imagine performing the action (O-MI), or imitate the action (O-IMIT). We found that when O-MI was compared to O, activation was enhanced in the ventralpremotor cortex bilaterally, left inferior parietal lobule and left insula. The O-MI and O-IMIT conditions shared many activation foci in motor relevant areas as confirmed by conjunction analysis. These results show that (i) combining observation with motor imagery (O-MI) enhances activation compared to observation-only (O) in the relevant foot motor network and in regions responsible for attention, for control of goal-directed movements and for the awareness of causing an action, and (ii) it is possible to extensively activate the motor execution network using O-MI, even in the absence of overt movement. Our results may have implications for the development of novel virtual reality interactions for neurorehabilitation interventions and other applications involving training of motor tasks. PMID:24015241

  20. Enhanced Activation of Motor Execution Networks Using Action Observation Combined with Imagination of Lower Limb Movements

    PubMed Central

    Villiger, Michael; Estévez, Natalia; Hepp-Reymond, Marie-Claude; Kiper, Daniel; Kollias, Spyros S.; Eng, Kynan; Hotz-Boendermaker, Sabina

    2013-01-01

    The combination of first-person observation and motor imagery, i.e. first-person observation of limbs with online motor imagination, is commonly used in interactive 3D computer gaming and in some movie scenes. These scenarios are designed to induce a cognitive process in which a subject imagines himself/herself acting as the agent in the displayed movement situation. Despite the ubiquity of this type of interaction and its therapeutic potential, its relationship to passive observation and imitation during observation has not been directly studied using an interactive paradigm. In the present study we show activation resulting from observation, coupled with online imagination and with online imitation of a goal-directed lower limb movement using functional MRI (fMRI) in a mixed block/event-related design. Healthy volunteers viewed a video (first-person perspective) of a foot kicking a ball. They were instructed to observe-only the action (O), observe and simultaneously imagine performing the action (O-MI), or imitate the action (O-IMIT). We found that when O-MI was compared to O, activation was enhanced in the ventralpremotor cortex bilaterally, left inferior parietal lobule and left insula. The O-MI and O-IMIT conditions shared many activation foci in motor relevant areas as confirmed by conjunction analysis. These results show that (i) combining observation with motor imagery (O-MI) enhances activation compared to observation-only (O) in the relevant foot motor network and in regions responsible for attention, for control of goal-directed movements and for the awareness of causing an action, and (ii) it is possible to extensively activate the motor execution network using O-MI, even in the absence of overt movement. Our results may have implications for the development of novel virtual reality interactions for neurorehabilitation interventions and other applications involving training of motor tasks. PMID:24015241

  1. Induction Motor Drive System Based on Linear Active Disturbance Rejection Controller

    NASA Astrophysics Data System (ADS)

    Liu, Liying; Zhang, Yongli; Yao, Qingmei

    It is difficult to establish an exact mathematical model for the induction motor and the robustness is poor of the vector control system using PI regulator. This paper adopts the linear active disturbance rejection controller (LADRC) to control inductor motor. LADRC doesn't need the exact mathematical model of motor and it can not only estimate but also compensate the general disturbance that includes the coupling items in model of motor and parameters perturbations by linear extended state observer (LESO), so the rotor flux and torque fully decouple. As a result, the performance is improved. To prove the above control scheme, the proposed control system has been simulated in MATLAB/SIMULINK, and the comparison was made with PID. Simulation results show that LADRC' has better performance and robustness than PID.

  2. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex

    PubMed Central

    Marins, Theo F.; Rodrigues, Erika C.; Engel, Annerose; Hoefle, Sebastian; Basílio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke. PMID:26733832

  3. Enhancing Motor Network Activity Using Real-Time Functional MRI Neurofeedback of Left Premotor Cortex.

    PubMed

    Marins, Theo F; Rodrigues, Erika C; Engel, Annerose; Hoefle, Sebastian; Basílio, Rodrigo; Lent, Roberto; Moll, Jorge; Tovar-Moll, Fernanda

    2015-01-01

    Neurofeedback by functional magnetic resonance imaging (fMRI) is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC), important for motor recovery after brain injury. We investigated (i) whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI) task while receiving continuous fMRI-neurofeedback, and (ii) whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB) received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL) group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and MI, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke. PMID:26733832

  4. Optogenetic activation of nigral inhibitory inputs to motor thalamus in the mouse reveals classic inhibition with little potential for rebound activation.

    PubMed

    Edgerton, Jeremy R; Jaeger, Dieter

    2014-01-01

    The inhibitory output from the internal pallidum and substantia nigra to the thalamus forms an important link in the transmission of basal ganglia processing to cortex. Two hypotheses consider either inhibition of thalamic activity or thalamic excitation via post-inhibitory rebound burst firing as the functional mode of this link. We used optogenetics to characterize the synaptic properties of nigral input to motor thalamus in adult mouse brain slices, and to determine in what conditions the nigral inhibition of motor thalamus is transmitted via inhibition or rebound firing. Our results are more consistent with graded inhibition of spiking for conditions expected in normal awake animals, because inhibitory potentials from nigral input were generally not sufficient to elicit rebound spikes when the thalamic neurons were actively firing. However, with bursty or fast trains of nigral input low-threshold rebound spike bursts could be triggered for low levels of excitation. This may form the basis of pathological burst generation and transmission in parkinsonian conditions. PMID:24574972

  5. Effects of acute and repeated zolpidem treatment on pentylenetetrazole-induced seizure threshold and on locomotor activity: comparison with diazepam.

    PubMed

    Vlainić, Josipa; Pericić, Danka

    2009-06-01

    Zolpidem and diazepam are widely used drugs acting via benzodiazepine binding sites on GABA(A) receptors. While diazepam is non-selective, zolpidem has a high affinity for alpha1-, and no affinity for alpha5-containing receptors. Several studies suggested that behavioral effects of zolpidem might be more similar to classical benzodiazepines than previously thought. To compare the sedative and anticonvulsant properties of these drugs and to evaluate the importance of GABA(A) receptor subunits for development of tolerance during chronic treatment, we tested the effects of acute and repeated administration of zolpidem and diazepam on ambulatory locomotor activity (a measure of sedation) and on the threshold for myoclonic, clonic and tonic seizures in response to i.v. infusion of pentylenetetrazole (PTZ). Both drugs given acutely in doses 0.3, 1 and 3 mg/kg reduced locomotion, and in doses 1 and 3 mg/kg elevated the threshold for PTZ-induced seizures. The effects of zolpidem and diazepam on the tonic seizure threshold were greater than on myoclonus and clonic seizure threshold. Diazepam and zolpidem (3 mg/kg), given 18 or 42 h after repeated drug treatment (10 days, 5 mg/kg, twice daily), decreased the PTZ seizure threshold and increased the locomotor activity as compared to control mice, indicating development of tolerance to their anticonvulsant and sedative effects. After repeated treatment the PTZ seizure threshold was not different between the two drugs, while differences in sedation became larger than after the acute treatment. The results suggest that alpha5-containing GABA(A) receptors are not crucial for the development of sedative and anticonvulsant tolerance. PMID:19345234

  6. Primary motor cortex neurons classified in a postural task predict muscle activation patterns in a reaching task.

    PubMed

    Heming, Ethan A; Lillicrap, Timothy P; Omrani, Mohsen; Herter, Troy M; Pruszynski, J Andrew; Scott, Stephen H

    2016-04-01

    Primary motor cortex (M1) activity correlates with many motor variables, making it difficult to demonstrate how it participates in motor control. We developed a two-stage process to separate the process of classifying the motor field of M1 neurons from the process of predicting the spatiotemporal patterns of its motor field during reaching. We tested our approach with a neural network model that controlled a two-joint arm to show the statistical relationship between network connectivity and neural activity across different motor tasks. In rhesus monkeys, M1 neurons classified by this method showed preferred reaching directions similar to their associated muscle groups. Importantly, the neural population signals predicted the spatiotemporal dynamics of their associated muscle groups, although a subgroup of atypical neurons reversed their directional preference, suggesting a selective role in antagonist control. These results highlight that M1 provides important details on the spatiotemporal patterns of muscle activity during motor skills such as reaching. PMID:26843605

  7. The Longitudinal Course of Gross Motor Activity in Schizophrenia – Within and between Episodes

    PubMed Central

    Walther, Sebastian; Stegmayer, Katharina; Horn, Helge; Rampa, Luca; Razavi, Nadja; Müller, Thomas J.; Strik, Werner

    2015-01-01

    Schizophrenia is associated with heterogeneous course of positive and negative symptoms. In addition, reduced motor activity as measured by wrist actigraphy has been reported. However, longitudinal studies of spontaneous motor activity are missing. We aimed to explore whether activity levels were stable within and between psychotic episodes. Furthermore, we investigated the association with the course of negative symptoms. In 45 medicated patients, we investigated motor behavior within a psychotic episode. In addition, we followed 18 medicated patients across 2 episodes. Wrist actigraphy and psychopathological ratings were applied. Within an episode symptoms changed but activity levels did not vary systematically. Activity at baseline predicted the course of negative symptoms. Between two episodes activity recordings were much more stable. Again, activity at the index episode predicted the outcome of negative symptoms. In sum, spontaneous motor activity shares trait and state characteristics, the latter are associated with negative symptom course. Actigraphy may therefore become an important ambulatory instrument to monitor negative symptoms and treatment outcome in schizophrenia. PMID:25698981

  8. A Developmental Perspective on the Role of Motor Skill Competence in Physical Activity: An Emergent Relationship

    ERIC Educational Resources Information Center

    Stodden, David F.; Goodway, Jacqueline D.; Langendorfer, Stephen J.; Roberton, Mary Ann; Rudisill, Mary E.; Garcia, Clersida; Garcia, Luis E.

    2008-01-01

    Although significant attention has been paid to promoting the importance of physical activity in children, adolescents, and adults, we do not currently understand how to promote sustained physical activity levels throughout the lifespan. We contend that previous research has failed to consider the dynamic and synergistic role that motor skill…

  9. Modulation of Motor Area Activity during Observation of Unnatural Body Movements

    ERIC Educational Resources Information Center

    Shimada, Sotaro; Oki, Kazuma

    2012-01-01

    The mirror neuron system (MNS) is activated when observing the actions of others. However, it remains unclear whether the MNS responds more strongly to natural bodily actions in the observer's motor repertoire than to unnatural actions. We investigated whether MNS activity is modulated by the unnaturalness of an observed action by inserting short…

  10. Microscopic origins of anisotropic active stress in motor-driven nematic liquid crystals.

    PubMed

    Blackwell, Robert; Sweezy-Schindler, Oliver; Baldwin, Christopher; Hough, Loren E; Glaser, Matthew A; Betterton, M D

    2016-03-14

    The cytoskeleton, despite comprising relatively few building blocks, drives an impressive variety of cellular phenomena ranging from cell division to motility. These building blocks include filaments, motor proteins, and static crosslinkers. Outside of cells, these same components can form novel materials exhibiting active flows and nonequilibrium contraction or extension. While dipolar extensile or contractile active stresses are common in nematic motor-filament systems, their microscopic origin remains unclear. Here we study a minimal physical model of filaments, crosslinking motors, and static crosslinkers to dissect the microscopic mechanisms of stress generation in a two-dimensional system of orientationally aligned rods. We demonstrate the essential role of filament steric interactions which have not previously been considered to significantly contribute to active stresses. With this insight, we are able to tune contractile or extensile behavior through the control of motor-driven filament sliding and crosslinking. This work provides a roadmap for engineering stresses in active liquid crystals. The mechanisms we study may help explain why flowing nematic motor-filament mixtures are extensile while gelled systems are contractile. PMID:26742483

  11. Motor speech impairment, activity, and participation in children with cerebral palsy.

    PubMed

    Mei, Cristina; Reilly, Sheena; Reddihough, Dinah; Mensah, Fiona; Morgan, Angela

    2014-08-01

    The present study used a population-based sample of children with cerebral palsy (CP) to estimate the prevalence of motor speech impairment and its association with activity and participation. A sample of 79 Victorian children aged 4 years 11 months to 6 years 5 months was recruited through the Victorian CP Register. The presence of motor speech impairment was recorded using the Viking Speech Scale (VSS). Activity and participation outcomes included speech intelligibility (the National Technical Institute for the Deaf rating scale, NTID), the Functional Communication Classification System (FCCS) and Communication Function Classification System (CFCS). A parent completed rating scale was used to examine the association between motor speech impairment and participation. Ninety per cent (71/79) of children demonstrated a motor speech impairment. Strong associations were found between the VSS and NTID (< .001), CFCS (< .001), and FCCS levels (<.001). VSS levels III-IV were significantly associated with restrictions in home, school, and community-based participation as perceived by parents. Although some diversity in activity and participation outcomes was observed within specific VSS levels, the results of this study suggested that children with mild motor speech impairments are more likely to demonstrate superior activity and participation outcomes compared to children with moderate or severe deficits. PMID:24910254

  12. Physiological basis and image processing in functional magnetic resonance imaging: Neuronal and motor activity in brain

    PubMed Central

    Sharma, Rakesh; Sharma, Avdhesh

    2004-01-01

    Functional magnetic resonance imaging (fMRI) is recently developing as imaging modality used for mapping hemodynamics of neuronal and motor event related tissue blood oxygen level dependence (BOLD) in terms of brain activation. Image processing is performed by segmentation and registration methods. Segmentation algorithms provide brain surface-based analysis, automated anatomical labeling of cortical fields in magnetic resonance data sets based on oxygen metabolic state. Registration algorithms provide geometric features using two or more imaging modalities to assure clinically useful neuronal and motor information of brain activation. This review article summarizes the physiological basis of fMRI signal, its origin, contrast enhancement, physical factors, anatomical labeling by segmentation, registration approaches with examples of visual and motor activity in brain. Latest developments are reviewed for clinical applications of fMRI along with other different neurophysiological and imaging modalities. PMID:15125779

  13. Twenty four hour manometric recording of colonic motor activity in healthy man.

    PubMed Central

    Narducci, F; Bassotti, G; Gaburri, M; Morelli, A

    1987-01-01

    The motor activity of the transverse, descending, and sigmoid colon was recorded for 24 hours in 14 healthy volunteers with a colonoscope positioned catheter. During the study the patients ate two 1000 kcal mixed meals and one continental breakfast. Colonic motor activity was low before meals and minimal during sleep; the motility index increased significantly after meals and at morning awakening. Most of the motor activity was represented by low amplitude contractions present singly or in bursts, which showed no recognisable pattern. All but two subjects also showed isolated high amplitude (up to 200 mmHg) contractions that propagated peristaltically over long distances at approximately 1 cm/sec. Most of these contractions occurred after morning awakening, and some in the late postprandial period, with a mean of 4.4/subject/24 h. The peristaltic contractions were often felt as an urge to defecate or preceded defecation, and could represent the manometric equivalent of the mass movements. PMID:3817580

  14. Action relevance in linguistic context drives word-induced motor activity

    PubMed Central

    Aravena, Pia; Courson, Mélody; Frak, Victor; Cheylus, Anne; Paulignan, Yves; Deprez, Viviane; Nazir, Tatjana A.

    2014-01-01

    Many neurocognitive studies on the role of motor structures in action-language processing have implicitly adopted a “dictionary-like” framework within which lexical meaning is constructed on the basis of an invariant set of semantic features. The debate has thus been centered on the question of whether motor activation is an integral part of the lexical semantics (embodied theories) or the result of a post-lexical construction of a situation model (disembodied theories). However, research in psycholinguistics show that lexical semantic processing and context-dependent meaning construction are narrowly integrated. An understanding of the role of motor structures in action-language processing might thus be better achieved by focusing on the linguistic contexts under which such structures are recruited. Here, we therefore analyzed online modulations of grip force while subjects listened to target words embedded in different linguistic contexts. When the target word was a hand action verb and when the sentence focused on that action (John signs the contract) an early increase of grip force was observed. No comparable increase was detected when the same word occurred in a context that shifted the focus toward the agent's mental state (John wants to sign the contract). There mere presence of an action word is thus not sufficient to trigger motor activation. Moreover, when the linguistic context set up a strong expectation for a hand action, a grip force increase was observed even when the tested word was a pseudo-verb. The presence of a known action word is thus not required to trigger motor activation. Importantly, however, the same linguistic contexts that sufficed to trigger motor activation with pseudo-verbs failed to trigger motor activation when the target words were verbs with no motor action reference. Context is thus not by itself sufficient to supersede an “incompatible” word meaning. We argue that motor structure activation is part of a dynamic process

  15. Increased atypical PKC expression and activity in the phrenic motor nucleus following cervical spinal injury

    PubMed Central

    Guenther, C.H.; Windelborn, J.A.; Tubon, T.C.; Yin, J.C.P.; Mitchell, G.S.

    2012-01-01

    Atypical protein kinase C (aPKC) isoforms are expressed in phrenic motor neurons, a group of motor neurons critical for breathing. Following C2 cervical hemisection (C2HS), spontaneous plasticity occurs in crossed-spinal synaptic pathways to phrenic motor neurons, at least partially restoring inspiratory phrenic activity below the injury. Since aPKCs are necessary for synaptic plasticity in other systems, we tested the hypothesis that C2HS increases aPKC expression and activity in spinal regions associated with the phrenic motor nucleus. C2 laminectomy (sham) or C2HS was performed on adult, male Lewis rats. Ventral spinal segments C3–5 were harvested 1, 3 or 28 days post-surgery, and prepared for aPKC enzyme activity assays and immunoblots. Ventral cervical aPKC activity was elevated 1 and 28, but not 3, days post-C2HS (1 day: 63% vs sham ipsilateral to injury; p<0.05; 28 day: 426% vs sham; p<0.05; no difference in ipsilateral vs contralateral response). Total PKCζ/ι protein expression was unchanged by C2HS, but total and phosphorylated PKMζ (constitutively active PKCζ isoform) increased ipsilateral to injury 28 days post-C2HS (p<0.05). Ipsilateral aPKC activity and expression were strongly correlated (r2=0.675, p<0.001). In a distinct group of rats, immunohistochemistry confirmed that aPKCs are expressed in neurons 28 days post-C2HS, including large, presumptive phrenic motor neurons; aPKCs were not detected in adjacent microglia (OX-42 positive cells) or astrocytes (GFAP positive cells). Changes in aPKC expression in the phrenic motor nucleus following C2HS suggests that aPKCs may contribute to functional recovery following cervical spinal injury. PMID:22329943

  16. Excitability of spinal motor neurons during motor imagery of thenar muscle activity under maximal voluntary contractions of 50% and 100%

    PubMed Central

    Bunno, Yoshibumi; Onigata, Chieko; Suzuki, Toshiaki

    2015-01-01

    [Purpose] We often perform physical therapy using motor imagery of muscle contraction to improve motor function for healthy subjects and central nerve disorders. This study aimed to determine the differences in the excitability of spinal motor neurons during motor imagery of a muscle contraction at different contraction strengths. [Subjects] We recorded the F-wave in 15 healthy subjects. [Methods] In resting trial, the muscle was relaxed during F-wave recording. For motor imagery trial, subjects were instructed to imagine maximal voluntary contractions of 50% and 100% while holding the sensor of a pinch meter, and F-waves were recorded for each contraction. The F-wave was recorded immediately after motor imagery. [Results] Persistence and F/M amplitude ratio during motor imagery under maximal voluntary contractions of 50% and 100% were significantly higher than that at rest. In addition, the relative values of persistence, F/M amplitude ratio, and latency were similar during motor imagery under the two muscle contraction strengths. [Conclusion] Motor imagery under maximal voluntary contractions of 50% and 100% can increase the excitability of spinal motor neurons. Differences in the imagined muscle contraction strengths are not involved in changes in the excitability of spinal motor neurons. PMID:26504291

  17. Coherence of EMG activity and single motor unit discharge patterns in human rhythmical force production.

    PubMed

    Sosnoff, Jacob J; Vaillancourt, David E; Larsson, Lars; Newell, Karl M

    2005-03-30

    The purpose of this study was to examine the modulation of the motor neuronal pool as a function of task dynamics. Specifically, we investigated the effects of task frequency on the single motor unit discharge pattern, electromyogram (EMG) activity and effector force output. Myoelectric activity and effector force were recorded while young adults isometrically abducted their first dorsal interosseus at five sinusoidal targets (0.5 Hz, 1 Hz, 2 Hz, 3 Hz and 4 Hz) and at two force levels (5% and 25% maximum voluntary contraction (MVC)). Individual motor unit spike trains were isolated from the EMG. Auto-spectral and coherence analyses were performed on the force output, EMG and motor unit spike trains. The frequency of maximal coherence between the EMG and force output closely corresponded to the target frequency in all conditions. There was a broadband distribution of power with multiple peaks in the EMG and motor unit spectrums in the 0.5 Hz and 1 Hz targets. However, the EMG and motor unit spectrums in the 2 Hz, 3 Hz and 4 Hz targets were characterized by an increasingly narrower band of activity with one dominant peak that closely corresponded to the target. There is high coherence between EMG output and target force frequency, but the relative contribution of the fast and slow neuromuscular bands are differentially influenced by the task frequency. The rhythmical organization of neuromuscular output in the 0.5 Hz task is relatively broadband and similar to that shown previously for constant level force output. The frequency structure of neuromuscular organization becomes increasingly more narrowband as the frequency of the target increases (2-4 Hz). The modulation of the motor neuronal pool is adaptive and depends on the relative contribution of feedback and feedforward control processes, which are driven by the task demands. PMID:15698897

  18. Stimulation of the ventral tegmental area increased nociceptive thresholds and decreased spinal dorsal horn neuronal activity in rat.

    PubMed

    Li, Ai-Ling; Sibi, Jiny E; Yang, Xiaofei; Chiao, Jung-Chih; Peng, Yuan Bo

    2016-06-01

    Deep brain stimulation has been found to be effective in relieving intractable pain. The ventral tegmental area (VTA) plays a role not only in the reward process, but also in the modulation of nociception. Lesions of VTA result in increased pain thresholds and exacerbate pain in several pain models. It is hypothesized that direct activation of VTA will reduce pain experience. In this study, we investigated the effect of direct electrical stimulation of the VTA on mechanical, thermal and carrageenan-induced chemical nociceptive thresholds in Sprague-Dawley rats using our custom-designed wireless stimulator. We found that: (1) VTA stimulation itself did not show any change in mechanical or thermal threshold; and (2) the decreased mechanical and thermal thresholds induced by carrageenan injection in the hind paw contralateral to the stimulation site were significantly reversed by VTA stimulation. To further explore the underlying mechanism of VTA stimulation-induced analgesia, spinal cord dorsal horn neuronal responses to graded mechanical stimuli were recorded. VTA stimulation significantly inhibited dorsal horn neuronal activity in response to pressure and pinch from the paw, but not brush. This indicated that VTA stimulation may have exerted its analgesic effect via descending modulatory pain pathways, possibly through its connections with brain stem structures and cerebral cortex areas. PMID:26821313

  19. A novel approach in automatic estimation of rats' loco-motor activity

    NASA Astrophysics Data System (ADS)

    Anishchenko, Lesya N.; Ivashov, Sergey I.; Vasiliev, Igor A.

    2014-05-01

    The paper contains feasibility study of a method for bioradar monitoring of small laboratory animals loco-motor activity improved by using a corner reflector. It presents results of mathematical simulation of bioradar signal reflection from the animal with the help of finite-difference time-domain method. It was proved both by theoretical and experimental results that a corner reflector usage during monitoring of small laboratory animals loco-motor activity improved the effectiveness of the method by reducing the dependency of the power flux density level from the distance between antennas block and the object.

  20. [Glutamatergic neurotransmitter system in regulation of the gastrointestinal tract motor activity].

    PubMed

    Alekseeva, E V; Popova, T S; Sal'nikov, P S

    2015-01-01

    The review include actual facts, demonstrating high probability of glutamatergic neurotransmitter system role in the regulation of the gastrointestinal tract motor activity. These facts suggest significant role of the glutamatergic neurotransmitter system dysfunction in forming motor activity disorders of the digestive tract, including in patients in critical condition. The analysis is based on results of multiple experimental and clinical researches of glutamic acid and other components of the glutamatergic neurotransmitter system in central nervous system and autonomic nervous system (with the accent on the enteral nervous system) in normal conditions and with functioning changes of the glutamatergic neurotransmitter system in case of inflammation, hupoxia, stress and in critical condition. PMID:26852608

  1. Regulation of pumping function of the heart in developing body under changing regimens of motor activity.

    PubMed

    Vafina, E Z; Abzalov, R A; Abzalov, N I; Nikitin, A S; Gulyakov, A A

    2014-06-01

    We analyzed parameters of the pumping function of the heart in rats subjected to enhanced motor activity after a preliminary 70-day hypokinesia under conditions of α- and β-adrenergic receptor stimulation with norepinephrine followed by blockade of β-adrenergic receptor with propranolol (obsidian) and α1-adrenergic receptors with doxazosin. After norepinephrine administration, the HR and cardiac output were higher in rats with enhanced physical activity after preliminary hypokinesia than in rats with low physical activity. After propranolol administration, stroke volume and cardiac output in 100-day-old rats with limited activity were lower, and HR higher was than in rats with enhanced physical activity after preliminary 70-day hypokinesia. After administration of doxazosin, rats with limited motor activity demonstrated more pronounced changes in HR than rats with enhanced physical activity after preliminary 70-day hypokinesia. PMID:24970234

  2. The Promotion of Gross and Fine Motor Development for Infants and Toddlers: Developmentally Appropriate Activities for Parents and Teachers.

    ERIC Educational Resources Information Center

    Thompson, Debra S.

    In recognition of the close relationship between motor skill and cognitive development in the first 2 years of life, this guide presents 78 developmentally appropriate activities that parents and teachers can use to enhance infant and toddler motor development. Activities are categorized by age group as follows: (1) 16 activities for newborn to…

  3. The Impact of Physical Activity on Non-Motor Symptoms in Parkinson's Disease: A Systematic Review.

    PubMed

    Cusso, Melanie E; Donald, Kenneth J; Khoo, Tien K

    2016-01-01

    Parkinson's disease (PD) is a neurological disorder that is associated with both motor and non-motor symptoms (NMS). The management of PD is primarily via pharmaceutical treatment; however, non-pharmaceutical interventions have become increasingly recognized in the management of motor and NMS. In this review, the efficacy of physical activity, including physiotherapy and occupational therapy, as an intervention in NMS will be assessed. The papers were extracted between the 20th and 22nd of June 2016 from PubMed, Web of Science, Medline, Ovid, SportsDiscuss, and Scopus using the MeSH search terms "Parkinson's," "Parkinson," and "Parkinsonism" in conjunction with "exercise," "physical activity," "physiotherapy," "occupational therapy," "physical therapy," "rehabilitation," "dance," and "martial arts." Twenty studies matched inclusion criteria of having 10 or more participants with diagnosed idiopathic PD participating in the intervention as well as having to evaluate the effects of physical activity on NMS in PD as controlled, randomized intervention studies. The outcomes of interest were NMS, including depression, cognition, fatigue, apathy, anxiety, and sleep. Risk of bias in the studies was evaluated using the Cochrane Collaboration's tool for assessing risk of bias. Comparability of the various intervention methods, however, was challenging due to demographic variability and methodological differences. Nevertheless, physical activity can positively impact the global NMS burden including depression, apathy, fatigue, day time sleepiness, sleep, and cognition, thus supporting its therapeutic potential in neurodegenerative conditions such as PD. It is recommended that further adequately powered studies are conducted to assess the therapeutic role of physical activity on both motor and non-motor aspects of PD. These studies should be optimally designed to assess non-motor elements of disease using instruments validated in PD. PMID:27583249

  4. Lost for emotion words: what motor and limbic brain activity reveals about autism and semantic theory.

    PubMed

    Moseley, Rachel L; Shtyrov, Yury; Mohr, Bettina; Lombardo, Michael V; Baron-Cohen, Simon; Pulvermüller, Friedemann

    2015-01-01

    Autism spectrum conditions (ASC) are characterised by deficits in understanding and expressing emotions and are frequently accompanied by alexithymia, a difficulty in understanding and expressing emotion words. Words are differentially represented in the brain according to their semantic category and these difficulties in ASC predict reduced activation to emotion-related words in limbic structures crucial for affective processing. Semantic theories view 'emotion actions' as critical for learning the semantic relationship between a word and the emotion it describes, such that emotion words typically activate the cortical motor systems involved in expressing emotion actions such as facial expressions. As ASC are also characterised by motor deficits and atypical brain structure and function in these regions, motor structures would also be expected to show reduced activation during emotion-semantic processing. Here we used event-related fMRI to compare passive processing of emotion words in comparison to abstract verbs and animal names in typically-developing controls and individuals with ASC. Relatively reduced brain activation in ASC for emotion words, but not matched control words, was found in motor areas and cingulate cortex specifically. The degree of activation evoked by emotion words in the motor system was also associated with the extent of autistic traits as revealed by the Autism Spectrum Quotient. We suggest that hypoactivation of motor and limbic regions for emotion word processing may underlie difficulties in processing emotional language in ASC. The role that sensorimotor systems and their connections might play in the affective and social-communication difficulties in ASC is discussed. PMID:25278250

  5. Lost for emotion words: What motor and limbic brain activity reveals about autism and semantic theory

    PubMed Central

    Moseley, Rachel L.; Shtyrov, Yury; Mohr, Bettina; Lombardo, Michael V.; Baron-Cohen, Simon; Pulvermüller, Friedemann

    2015-01-01

    Autism spectrum conditions (ASC) are characterised by deficits in understanding and expressing emotions and are frequently accompanied by alexithymia, a difficulty in understanding and expressing emotion words. Words are differentially represented in the brain according to their semantic category and these difficulties in ASC predict reduced activation to emotion-related words in limbic structures crucial for affective processing. Semantic theories view ‘emotion actions’ as critical for learning the semantic relationship between a word and the emotion it describes, such that emotion words typically activate the cortical motor systems involved in expressing emotion actions such as facial expressions. As ASC are also characterised by motor deficits and atypical brain structure and function in these regions, motor structures would also be expected to show reduced activation during emotion-semantic processing. Here we used event-related fMRI to compare passive processing of emotion words in comparison to abstract verbs and animal names in typically-developing controls and individuals with ASC. Relatively reduced brain activation in ASC for emotion words, but not matched control words, was found in motor areas and cingulate cortex specifically. The degree of activation evoked by emotion words in the motor system was also associated with the extent of autistic traits as revealed by the Autism Spectrum Quotient. We suggest that hypoactivation of motor and limbic regions for emotion word processing may underlie difficulties in processing emotional language in ASC. The role that sensorimotor systems and their connections might play in the affective and social-communication difficulties in ASC is discussed. PMID:25278250

  6. The Effects of Environmental Stimulation on the Perceptual Thresholds of High-Active and Low-Active Mentally Retarded Persons. IMRID Behavioral Science Monograph No. 15.

    ERIC Educational Resources Information Center

    Lucker, William Glasgow

    In order to assess the effects of environmental stimulation on the perceptual thresholds of high active and low active mentally retarded persons, 36 male and female residents from a state institution (mean IQ 56 and 60 for high and low groups, respectively) were observed under three conditions of environmental stimulation: no noise, white noise,…

  7. Active Female Maximal and Anaerobic Threshold Cardiorespiratory Responses to Six Different Water Aerobics Exercises

    ERIC Educational Resources Information Center

    Antunes, Amanda H.; Alberton, Cristine L.; Finatto, Paula; Pinto, Stephanie S.; Cadore, Eduardo L.; Zaffari, Paula; Kruel, Luiz F. M.

    2015-01-01

    Purpose: Maximal tests conducted on land are not suitable for the prescription of aquatic exercises, which makes it difficult to optimize the intensity of water aerobics classes. The aim of the present study was to evaluate the maximal and anaerobic threshold cardiorespiratory responses to 6 water aerobics exercises. Volunteers performed 3 of the…

  8. 78 FR 38348 - Agency Information Collection Activities; Proposed Collection; Comment Request; Threshold of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-26

    ... Collection; Comment Request; Threshold of Regulation for Substances Used in Food- Contact Articles AGENCY... for Substances Used in Food-Contact Articles. DATES: Submit either electronic or written comments on... brackets in the heading of this document. FOR FURTHER INFORMATION CONTACT: Domini Bean, Office...

  9. 75 FR 18209 - Agency Information Collection Activities; Proposed Collection; Comment Request; Threshold of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... Collection; Comment Request; Threshold of Regulation for Substances Used in Food- Contact Articles AGENCY... number found in brackets in the heading of this document. FOR FURTHER INFORMATION CONTACT: Denver Presley... Substances Used in Food-Contact Articles-- 21 CFR 170.39 (OMB Control Number 0910-0298)--Extension...

  10. Influence of Tableting on Enzymatic Activity of Papain along with Determination of Its Percolation Threshold with Microcrystalline Cellulose

    PubMed Central

    Sharma, Manu; Sharma, Vinay; Majumdar, Dipak K.

    2014-01-01

    The binary mixture tablets of papain and microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), carrageenan, tragacanth, and agar were prepared by direct compression. Carrageenan, tragacanth, and agar provided maximum protection to enzyme activity compared to MCC and DCP. However, stability studies indicated highest loss of enzyme activity with carrageenan, tragacanth, and agar. Therefore, compression behaviour of different binary mixtures of papain with MCC at different compaction pressures, that is, 40–280 MPa, was studied according to Heckel equation. The compressibility studies of binary mixtures indicated brittle behavior of papain. The application of percolation theory on the relationship between critical density as a function of enzyme activity and mixture composition revealed the presence of percolation threshold for binary mixture. Papain-MCC mixture composition showed significant percolation threshold at 18.48% (w/w) papain loading. Microcrystalline cellulose provided higher protection during stability study. However, higher concentrations of microcrystalline cellulose, probably as dominant particles, do not protect the enzyme with their plastic deformation. Below the percolation threshold, that is, 18.48% (w/w) papain amount in mixture with plastic excipient, activity loss increases strongly because of higher shearing forces during compaction due to system dominance of plastic particles. This mixture range should therefore be avoided to get robust formulation of papain. PMID:27350972

  11. EEG spectra, behavioral states and motor activity in rats exposed to acetylcholinesterase inhibitor chlorpyrifos.

    PubMed

    Timofeeva, Olga A; Gordon, Christopher J

    2002-06-01

    Exposure to organophosphates (OP) has been associated with sleep disorders such as insomnia and "excessive dreaming." The central mechanisms of these effects are not well understood. OPs inhibit acetylcholinesterase (AChE) activity, leading to a hyperactivity of the brain cholinergic systems that are involved in sleep regulation. We studied alterations in the EEG, behavioral states, motor activity and core temperature in rats orally administered with 10 or 40 mg/kg of the OP insecticide chlorpyrifos (CHP). Occipital EEG, motor activity and core temperature were recorded with telemetric transmitters. Behavioral sleep-wake states were visually scored. Both doses of CHP produced alterations of the EEG (decrease in power of sigma/beta and increase in slow theta and fast gamma bands) characteristic of arousal. EEG alterations were consistent with behavioral changes such as an increase in wakefulness and a decrease in sleep. Waking immobility was a prevalent behavior. We did not detect any overt signs of CHP toxicity, such as an abnormal posture or gait, suggesting that reduced locomotion can be a result of central effects of CHP (such as activation of cholinergic motor inhibitory system) rather than peripheral (such as an impairment of neuromuscular function). Changes in the EEG and behavior occurred independently of the decrease in core temperature. Increased wakefulness together with reduced motor activity after exposure to CHP seems to be a result of hyperactivity in brain cholinergic neuronal networks. PMID:12175464

  12. Quantification of motor cortex activity and full-body biomechanics during unconstrained locomotion.

    PubMed

    Prilutsky, Boris I; Sirota, Mikhail G; Gregor, Robert J; Beloozerova, Irina N

    2005-10-01

    Recent progress in the understanding of motor cortex function has been achieved primarily by simultaneously recording motor cortex neuron activity and the movement kinematics of the corresponding limb. We have expanded this approach by combining high-quality cortical single-unit activity recordings with synchronized recordings of full-body kinematics and kinetics in the freely behaving cat. The method is illustrated by selected results obtained from two cats tested while walking on a flat surface. Using this method, the activity of 43 pyramidal tract neurons (PTNs) was recorded, averaged over 10 bins of a locomotion cycle, and compared with full-body mechanics by means of principal component and multivariate linear regression analyses. Patterns of 24 PTNs (56%) and 219 biomechanical variables (73%) were classified into just four groups of inter-correlated variables that accounted for 91% of the total variance, indicating that many of the recorded variables had similar patterns. The ensemble activity of different groups of two to eight PTNs accurately predicted the 10-bin patterns of all biomechanical variables (neural decoding) and vice versa; different small groups of mechanical variables accurately predicted the 10-bin pattern of each PTN (neural encoding). We conclude that comparison of motor cortex activity with full-body biomechanics may be a useful tool in further elucidating the function of the motor cortex. PMID:15888524

  13. Influence of motor imagination on cortical activation during functional electrical stimulation

    PubMed Central

    Reynolds, Clare; Osuagwu, Bethel A.; Vuckovic, Aleksandra

    2015-01-01

    Objective Motor imagination (MI) and functional electrical stimulation (FES) can activate the sensory-motor cortex through efferent and afferent pathways respectively. Motor imagination can be used as a control strategy to activate FES through a brain–computer interface as the part of a rehabilitation therapy. It is believed that precise timing between the onset of MI and FES is important for strengthening the cortico-spinal pathways but it is not known whether prolonged MI during FES influences cortical response. Methods Electroencephalogram was measured in ten able-bodied participants using MI strategy to control FES through a BCI system. Event related synchronisation/desynchronisation (ERS/ERD) over the sensory-motor cortex was analysed and compared in three paradigms: MI before FES, MI before and during FES and FES alone activated automatically. Results MI practiced both before and during FES produced strongest ERD. When MI only preceded FES it resulted in a weaker beta ERD during FES than when FES was activated automatically. Following termination of FES, beta ERD returns to the baseline level within 0.5 s while alpha ERD took longer than 1 s. Conclusions When MI and FES are combined for rehabilitation purposes it is recommended that MI is practiced throughout FES activation period. Significance The study is relevant for neurorehabilitation of movement. PMID:25454278

  14. Spatiotemporal relations of primary sensorimotor and secondary motor activation patterns mapped by NIR imaging

    PubMed Central

    Khan, Bilal; Chand, Pankaj; Alexandrakis, George

    2011-01-01

    Functional near infrared (fNIR) imaging was used to identify spatiotemporal relations between spatially distinct cortical regions activated during various hand and arm motion protocols. Imaging was performed over a field of view (FOV, 12 x 8.4 cm) including the secondary motor, primary sensorimotor, and the posterior parietal cortices over a single brain hemisphere. This is a more extended FOV than typically used in current fNIR studies. Three subjects performed four motor tasks that induced activation over this extended FOV. The tasks included card flipping (pronation and supination) that, to our knowledge, has not been performed in previous functional magnetic resonance imaging (fMRI) or fNIR studies. An earlier rise and a longer duration of the hemodynamic activation response were found in tasks requiring increased physical or mental effort. Additionally, analysis of activation images by cluster component analysis (CCA) demonstrated that cortical regions can be grouped into clusters, which can be adjacent or distant from each other, that have similar temporal activation patterns depending on whether the performed motor task is guided by visual or tactile feedback. These analyses highlight the future potential of fNIR imaging to tackle clinically relevant questions regarding the spatiotemporal relations between different sensorimotor cortex regions, e.g. ones involved in the rehabilitation response to motor impairments. PMID:22162826

  15. Automatic ultrarapid activation and inhibition of cortical motor systems in spoken word comprehension.

    PubMed

    Shtyrov, Yury; Butorina, Anna; Nikolaeva, Anastasia; Stroganova, Tatiana

    2014-05-01

    To address the hotly debated question of motor system involvement in language comprehension, we recorded neuromagnetic responses elicited in the human brain by unattended action-related spoken verbs and nouns and scrutinized their timecourse and neuroanatomical substrates. We found that already very early on, from ∼80 ms after disambiguation point when the words could be identified from the available acoustic information, both verbs and nouns produced characteristic somatotopic activations in the motor strip, with words related to different body parts activating the corresponding body representations. Strikingly, along with this category-specific activation, we observed suppression of motor-cortex activation by competitor words with incompatible semantics, documenting operation of the neurophysiological principles of lateral/surround inhibition in neural word processing. The extremely early onset of these activations and deactivations, their emergence in the absence of attention, and their similar presence for words of different lexical classes strongly suggest automatic involvement of motor-specific circuits in the perception of action-related language. PMID:24753617

  16. Brain oscillatory activity during motor imagery in EEG-fMRI coregistration.

    PubMed

    Formaggio, Emanuela; Storti, Silvia Francesca; Cerini, Roberto; Fiaschi, Antonio; Manganotti, Paolo

    2010-12-01

    The purpose of the present work was to investigate the correlation between topographical changes in brain oscillatory activity and the blood oxygenation level-dependent (BOLD) signal during a motor imagery (MI) task using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) coregistration. EEG was recorded in 7 healthy subjects inside a 1.5 T MR scanner during the imagination of the kinesthetic experience of movement. A Fast Fourier Transform was applied to EEG signal in the rest and active conditions. We used the event-related-synchronization (ERS)/desynchronization (ERD) approach to characterize where the imagination of movement produces a decrease in alpha and beta power. The mean alpha map showed ERD decrease localized over the contralateral sensory motor area (SM1c) and a light desynchronization in the ipsilateral sensory motor area (SM1i); whereas the mean beta map showed ERD decrease over the supplementary motor area (SMA). fMRI showed significant activation in SMA, SM1c, SM1i. The correlation is negative in the contralateral side and positive in the ipsilateral side. Using combined EEG-fMRI signals we obtained useful new information on the description of the changes in oscillatory activity in alpha and beta bands during MI and on the investigation of the sites of BOLD activity as possible sources in generating these rhythms. By correlating BOLD and ERD/ERS we may identify more accurately which regions contribute to changes of the electrical response. PMID:20850237

  17. Neuroinflammation contributes to hypokinesia in rats with hepatic encephalopathy: ibuprofen restores its motor activity.

    PubMed

    Cauli, Omar; Rodrigo, Regina; Piedrafita, Blanca; Llansola, Marta; Mansouri, Mohammad T; Felipo, Vicente

    2009-05-01

    Patients with hepatic encephalopathy show altered motor function, psychomotor slowing, and hypokinesia, which are reproduced in rats with portacaval shunts (PCS). Increased extracellular glutamate in substantia nigra pars reticulata (SNr) is responsible for hypokinesia in PCS rats. The mechanisms by which liver failure leads to increased extracellular glutamate in SNr remain unclear. Inflammation seems to act synergistically with hyperammonemia to induce neurological alterations in hepatic encephalopathy. It is therefore possible that inflammation-associated alterations may contribute to motor alterations in hepatic encephalopathy. The aim of this work was to assess whether treatment with an antiinflammatory, ibuprofen, is able to normalize extracellular glutamate in SNr and/or to improve hypokinesia in PCS rats. The amounts of the glutamate transporters GLT-1 and EAAC-1 are reduced by 26% and 32%, respectively, in SNr of PCS rats. This reduction is associated with a tenfold increase in extracellular glutamate in SNr and a reduction in motor activity. Chronic treatment with 30 mg/kg ibuprofen completely normalizes the amount of GLT-1 and EAAC-1 and significantly reduces (by 53%) extracellular glutamate in SNr of PCS rats. Moreover, ibuprofen, at 15 or 30 (but not at 5) mg/kg/day, completely eliminates hypokinesia, restoring normal motor activity. This supports the idea that inflammation is a main contributor to the induction of hypokinesia in hepatic encephalopathy. Moreover, these data point to the possible therapeutic utility of decreasing inflammation, by safe procedures, in the treatment of the motor deficits in patients with hepatic encephalopathy. PMID:19025766

  18. Spinal atypical protein kinase C activity is necessary to stabilize inactivity-induced phrenic motor facilitation

    PubMed Central

    Strey, K.A.; Nichols, N.L.; Baertsch, N.A.; Broytman, O.; Baker-Herman, T.L.

    2012-01-01

    The neural network controlling breathing must establish rhythmic motor output at a level adequate to sustain life. Reduced respiratory neural activity elicits a novel form of plasticity in circuits driving the diaphragm known as inactivity-induced phrenic motor facilitation (iPMF), a rebound increase in phrenic inspiratory output observed once respiratory neural drive is restored. The mechanisms underlying iPMF are unknown. Here, we demonstrate in anesthetized rats that spinal mechanisms give rise to iPMF, and that iPMF consists of at least two mechanistically distinct phases: 1) an early, labile phase that requires atypical PKC (PKCζ and/or PKCΙ/λ) activity to transition to a 2) late, stable phase. Early (but not late) iPMF is associated with increased interactions between PKCζ/Ι and the scaffolding protein ZIP/p62 in spinal regions associated with the phrenic motor pool. Although PKCζ/Ι activity is necessary for iPMF, spinal aPKC activity is not necessary for phrenic long-term facilitation (pLTF) following acute intermittent hypoxia, an activity-independent form of spinal respiratory plasticity. Thus, while iPMF and pLTF both manifest as prolonged increases in phrenic burst amplitude, they arise from distinct spinal cellular pathways. Our data are consistent with the hypotheses that: 1) local mechanisms sense and respond to reduced respiratory-related activity in the phrenic motor pool, and 2) inactivity-induced increases in phrenic inspiratory output require local PKCζ/Ι activity to stabilize into a long-lasting iPMF. Although the physiological role of iPMF is unknown, we suspect that iPMF represents a compensatory mechanism, assuring adequate motor output in a physiological system where prolonged inactivity ends life. PMID:23152633

  19. Spinal atypical protein kinase C activity is necessary to stabilize inactivity-induced phrenic motor facilitation.

    PubMed

    Strey, Kristi A; Nichols, Nicole L; Baertsch, Nathan A; Broytman, Oleg; Baker-Herman, Tracy L

    2012-11-14

    The neural network controlling breathing must establish rhythmic motor output at a level adequate to sustain life. Reduced respiratory neural activity elicits a novel form of plasticity in circuits driving the diaphragm known as inactivity-induced phrenic motor facilitation (iPMF), a rebound increase in phrenic inspiratory output observed once respiratory neural drive is restored. The mechanisms underlying iPMF are unknown. Here, we demonstrate in anesthetized rats that spinal mechanisms give rise to iPMF and that iPMF consists of at least two mechanistically distinct phases: (1) an early, labile phase that requires atypical PKC (PKCζ and/or PKCι/λ) activity to transition to a (2) late, stable phase. Early (but not late) iPMF is associated with increased interactions between PKCζ/ι and the scaffolding protein ZIP (PKCζ-interacting protein)/p62 in spinal regions associated with the phrenic motor pool. Although PKCζ/ι activity is necessary for iPMF, spinal atypical PKC activity is not necessary for phrenic long-term facilitation (pLTF) following acute intermittent hypoxia, an activity-independent form of spinal respiratory plasticity. Thus, while iPMF and pLTF both manifest as prolonged increases in phrenic burst amplitude, they arise from distinct spinal cellular pathways. Our data are consistent with the hypotheses that (1) local mechanisms sense and respond to reduced respiratory-related activity in the phrenic motor pool and (2) inactivity-induced increases in phrenic inspiratory output require local PKCζ/ι activity to stabilize into a long-lasting iPMF. Although the physiological role of iPMF is unknown, we suspect that iPMF represents a compensatory mechanism, assuring adequate motor output in a physiological system in which prolonged inactivity ends life. PMID:23152633

  20. Brain activity during observation and motor imagery of different balance tasks: an fMRI study.

    PubMed

    Taube, Wolfgang; Mouthon, Michael; Leukel, Christian; Hoogewoud, Henri-Marcel; Annoni, Jean-Marie; Keller, Martin

    2015-03-01

    After immobilization, patients show impaired postural control and increased risk of falling. Therefore, loss of balance control should already be counteracted during immobilization. Previously, studies have demonstrated that both motor imagery (MI) and action observation (AO) can improve motor performance. The current study elaborated how the brain is activated during imagination and observation of different postural tasks to provide recommendations about the conception of non-physical balance training. For this purpose, participants were tested in a within-subject design in an fMRI-scanner in three different conditions: (a) AO + MI, (b) AO, and (c) MI. In (a) participants were instructed to imagine themselves as the person pictured in the video whereas in (b) they were instructed simply to watch the video. In (c) subjects closed their eyes and kinesthetically imagined the task displayed in the video. Two tasks were evaluated in each condition: (i) static standing balance and (ii) dynamic standing balance (medio-lateral perturbation). In all conditions the start of a new trial was indicated every 2 sec by a sound. During AO + MI of the dynamic task, participants activated motor centers including the putamen, cerebellum, supplementary motor area, premotor cortices (PMv/d) and primary motor cortex (M1). MI showed a similar pattern but no activity in M1 and PMv/d. In the SMA and cerebellum, activity was generally higher in the dynamic than in the static condition. AO did not significantly activate any of these brain areas. Our results showed that (I) mainly AO + MI, but also MI, activate brain regions important for balance control; (II) participants display higher levels of brain activation in the more demanding balance task; (III) there is a significant difference between AO + MI and AO. Consequently, best training effects should be expected when participants apply MI during AO (AO + MI) of challenging postural tasks. PMID:25461711

  1. Differences in Movement Mechanics, Electromyographic, and Motor Cortex Activity Between Accurate and Nonaccurate Stepping

    PubMed Central

    Farrell, Bradley J.; Sirota, Mikhail G.; Prilutsky, Boris I.

    2010-01-01

    What are the differences in mechanics, muscle, and motor cortex activity between accurate and nonaccurate movements? We addressed this question in relation to walking. We assessed full-body mechanics (229 variables), activity of 8 limb muscles, and activity of 63 neurons from the motor cortex forelimb representation during well-trained locomotion with different demands on the accuracy of paw placement in cats: during locomotion on a continuous surface and along horizontal ladders with crosspieces of different widths. We found that with increasing accuracy demands, cats assumed a more bent-forward posture (by lowering the center of mass, rotating the neck and head down, and by increasing flexion of the distal joints) and stepped on the support surface with less spatial variability. On the ladder, the wrist flexion moment was lower throughout stance, whereas ankle and knee extension moments were higher and hip moment was lower during early stance compared with unconstrained locomotion. The horizontal velocity time histories of paws were symmetric and smooth and did not differ among the tasks. Most of the other mechanical variables also did not depend on accuracy demands. Selected distal muscles slightly enhanced their activity with increasing accuracy demands. However, in a majority of motor cortex cells, discharge rate means, peaks, and depths of stride-related frequency modulation changed dramatically during accurate stepping as compared with simple walking. In addition, in 30% of neurons periods of stride-related elevation in firing became shorter and in 20–25% of neurons activity or depth of frequency modulation increased, albeit not linearly, with increasing accuracy demands. Considering the relatively small changes in locomotor mechanics and substantial changes in motor cortex activity with increasing accuracy demands, we conclude that during practiced accurate stepping the activity of motor cortex reflects other processes, likely those that involve

  2. Differences in movement mechanics, electromyographic, and motor cortex activity between accurate and nonaccurate stepping.

    PubMed

    Beloozerova, Irina N; Farrell, Bradley J; Sirota, Mikhail G; Prilutsky, Boris I

    2010-04-01

    What are the differences in mechanics, muscle, and motor cortex activity between accurate and nonaccurate movements? We addressed this question in relation to walking. We assessed full-body mechanics (229 variables), activity of 8 limb muscles, and activity of 63 neurons from the motor cortex forelimb representation during well-trained locomotion with different demands on the accuracy of paw placement in cats: during locomotion on a continuous surface and along horizontal ladders with crosspieces of different widths. We found that with increasing accuracy demands, cats assumed a more bent-forward posture (by lowering the center of mass, rotating the neck and head down, and by increasing flexion of the distal joints) and stepped on the support surface with less spatial variability. On the ladder, the wrist flexion moment was lower throughout stance, whereas ankle and knee extension moments were higher and hip moment was lower during early stance compared with unconstrained locomotion. The horizontal velocity time histories of paws were symmetric and smooth and did not differ among the tasks. Most of the other mechanical variables also did not depend on accuracy demands. Selected distal muscles slightly enhanced their activity with increasing accuracy demands. However, in a majority of motor cortex cells, discharge rate means, peaks, and depths of stride-related frequency modulation changed dramatically during accurate stepping as compared with simple walking. In addition, in 30% of neurons periods of stride-related elevation in firing became shorter and in 20-25% of neurons activity or depth of frequency modulation increased, albeit not linearly, with increasing accuracy demands. Considering the relatively small changes in locomotor mechanics and substantial changes in motor cortex activity with increasing accuracy demands, we conclude that during practiced accurate stepping the activity of motor cortex reflects other processes, likely those that involve integration

  3. Using hierarchical clustering methods to classify motor activities of COPD patients from wearable sensor data

    PubMed Central

    Sherrill, Delsey M; Moy, Marilyn L; Reilly, John J; Bonato, Paolo

    2005-01-01

    Background Advances in miniature sensor technology have led to the development of wearable systems that allow one to monitor motor activities in the field. A variety of classifiers have been proposed in the past, but little has been done toward developing systematic approaches to assess the feasibility of discriminating the motor tasks of interest and to guide the choice of the classifier architecture. Methods A technique is introduced to address this problem according to a hierarchical framework and its use is demonstrated for the application of detecting motor activities in patients with chronic obstructive pulmonary disease (COPD) undergoing pulmonary rehabilitation. Accelerometers were used to collect data for 10 different classes of activity. Features were extracted to capture essential properties of the data set and reduce the dimensionality of the problem at hand. Cluster measures were utilized to find natural groupings in the data set and then construct a hierarchy of the relationships between clusters to guide the process of merging clusters that are too similar to distinguish reliably. It provides a means to assess whether the benefits of merging for performance of a classifier outweigh the loss of resolution incurred through merging. Results Analysis of the COPD data set demonstrated that motor tasks related to ambulation can be reliably discriminated from tasks performed in a seated position with the legs in motion or stationary using two features derived from one accelerometer. Classifying motor tasks within the category of activities related to ambulation requires more advanced techniques. While in certain cases all the tasks could be accurately classified, in others merging clusters associated with different motor tasks was necessary. When merging clusters, it was found that the proposed method could lead to more than 12% improvement in classifier accuracy while retaining resolution of 4 tasks. Conclusion Hierarchical clustering methods are relevant

  4. Adaptive Thresholds

    SciTech Connect

    Bremer, P. -T.

    2014-08-26

    ADAPT is a topological analysis code that allow to compute local threshold, in particular relevance based thresholds for features defined in scalar fields. The initial target application is vortex detection but the software is more generally applicable to all threshold based feature definitions.

  5. The Reinforcement of First Grade Science Concepts with the Use of Motor Learning Activities.

    ERIC Educational Resources Information Center

    Prager, Iris J.

    In order to test the theory that selected first-grade science concepts could be successfully reinforced with the use of motor activities, 52 first-graders were exposed to certain experimental procedures. Two separate classes of 25 students (group A) and 27 students (group B) underwent a pretest. Both classes were then taught through traditional…

  6. Effect of Robertsonian translocations on the motor activity rhythm in the house mouse.

    PubMed

    Sans-Fuentes, Maria Assumpció; López-Fuster, María José; Ventura, Jacint; Díez-Noguera, Antoni; Cambras, Trinitat

    2005-09-01

    Here we studied the circadian rhythm of motor activity in two groups of wild house mice from the chromosomal polymorphic zone of Barcelona, which differed in diploid number (2n): standard (2n = 40), with all acrocentric chromosomes, and Robertsonian (2n = 29-32), with several Robertsonian translocations. Motor activity under three lighting conditions, light-dark cycle, constant darkness, and constant light, was recorded for each mouse. The motor activity rhythm was examined by Fourier analysis and the daily power spectra were obtained. On the basis of the mean power spectrum of each animal and under each lighting condition, stepwise discriminant analyses were performed to classify the two chromosomal groups. This method allowed the correct classification of a large number of animals, the rhythms of about 2-2.6 hour periods being the most significant, with higher values in Robertsonian than in standard mice. Our results indicate that the daily motor activity pattern differs between the two chromosomal groups and its analysis may have a valuable interest for behavioral investigations on Robertsonian polymorphic zones of this species. PMID:16184488

  7. The influence of motor activity on the development of cardiac arrhythmias during experimental emotional stress

    NASA Technical Reports Server (NTRS)

    Ulyaninskiy, L. S.; Urmancheyeva, T. G.; Stepanyan, Y. P.; Fufacheva, A. A.; Gritsak, A. V.; Kuznetsova, B. A.; Kvitka, A. A.

    1982-01-01

    Experimental emotional stress which can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular, extrasystoles and paroxysmal ventricular tachysystoles was studied. In these conditions the adrenalin content in the blood and myocardium is increased 3 to 4 times. It is found that moderate motor activity leads to a relative decrease of adrenalin in the myocardium and arrest of cardiac arrhythmias.

  8. MOTOR ACTIVITY IN DEVELOPMENTAL NEUROTOXICITY TESTING: A CROSS-LABORATORY COMPARISON OF CONTROL DATA.

    EPA Science Inventory

    The USEPA Developmental Neurotoxicity (DNT) Study Test Guideline (OPPTS 870.6300) calls for a battery of functional and neuropathological assessments in offspring during and following maternal exposure. The battery includes measurement of motor activity on post-natal days (PND) ...

  9. INVESTIGATIONS OF AMITRAZ NEUROTOXICITY IN RATS. III. EFFECTS ON MOTOR ACTIVITY AND INHIBITION OF MONOAMINE OXIDASE

    EPA Science Inventory

    The formamidine pesticide amitraz (AMZ) produces many behavioral and physiological changes in rats. o explore possible neurochemical mechanisms for the behavioral effects of AMZ, we examined the dose effect and time course of AMZ on motor activity, monoamine oxidase (MAO) and ace...

  10. Less precise motor control leads to increased agonist-antagonist muscle activation during stick balancing.

    PubMed

    Reeves, N Peter; Popovich, John M; Vijayanagar, Vilok; Pathak, Pramod K

    2016-06-01

    Human motor control has constraints in terms of its responsiveness, which limit its ability to successfully perform tasks. In a previous study, it was shown that the ability to balance an upright stick became progressively more challenging as the natural frequency (angular velocity without control) of the stick increased. Furthermore, forearm and trunk agonist and antagonist muscle activation increased as the natural frequency of the stick increased, providing evidence that the central nervous system produces agonist-antagonist muscle activation to match task dynamics. In the present study, visual feedback of the stick position was influenced by changing where subject focused on the stick during stick balancing. It was hypothesized that a lower focal height would degrade motor control (more uncertainty in tracking stick position), thus making balancing more challenging. The probability of successfully balancing the stick at four different focal heights was determined along with the average angular velocity of the stick. Electromyographic signals from forearm and trunk muscles were also recorded. As expected, the probability of successfully balancing the stick decreased and the average angular velocity of the stick increased as subjects focused lower on the stick. In addition, changes in the level of agonist and antagonist muscle activation in the forearm and trunk was linearly related to changes in the angular velocity of the stick during balancing. One possible explanation for this is that the central nervous system increases muscle activation to account for less precise motor control, possibly to improve the responsiveness of human motor control. PMID:27010497

  11. Evidence for Dose-Additive Effects of Pyrethroids on Motor Activity in Rats

    EPA Science Inventory

    BACKGROUND: Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose-effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. OBJECTIVES...

  12. The Effect of Fine Motor Skill Activities on Kindergarten Student Attention

    ERIC Educational Resources Information Center

    Stewart, Roger A.; Rule, Audrey C.; Giordano, Debra A.

    2007-01-01

    This study explored the effect of fine motor skill activities on the development of attention in kindergarteners (n = 68) in five classes at a suburban public school in the Intermountain West through a pretest/posttest experimental group (n = 36) control group (n = 32) design. All children received the regular curriculum which included typical…

  13. TOLERANCE AND SENSITIZATION TO WEEKLY NICOTINE EXPOSURES ON THE MOTOR ACTIVITY OF RATS.

    EPA Science Inventory

    Motor activity was examined in adult female Long-Evans rats in a photocell device during daily (M-F) 30-min sessions. Following adaptation to the testing routine the rats were divided into six groups of eight that were designated to receive either nothing (non-injected control),...

  14. SENSITIZATION AND TOLERANCE WITH EPISODIC (WEEKLY) NICOTINE ON MOTOR ACTIVITY IN RATS.

    EPA Science Inventory

    These studies grew out of an unexpected finding from investigations of the neurobehavioral toxicity of PCBs. This paper shows that episodic, or recurring intermittent acute exposures to nicotine produce dramatic and long-lasting changes in the motor activity of laboratory rats. ...

  15. NEUROBEHAVIORAL DATA INTERPRETATION IN NEUROTOXICITY STUDIES: FOB, MOTOR ACTIVITY AND FUNCTION

    EPA Science Inventory

    Neurobehavioral evaluations are emerging as a key component in neurotoxicity testing. The tests most often used for screening are the functional observational battery (FOB) and motor activity. The FOB is a series of non-invasive observational and manipulative measures which ass...

  16. Educational Gymnastics: The Effectiveness of Montessori Practical Life Activities in Developing Fine Motor Skills in Kindergartners

    ERIC Educational Resources Information Center

    Bhatia, Punum; Davis, Alan; Shamas-Brandt, Ellen

    2015-01-01

    Research Findings: A quasi-experiment was undertaken to test the effect of Montessori practical life activities on kindergarten children's fine motor development and hand dominance over an 8-month period. Participants were 50 children age 5 in 4 Montessori schools and 50 students age 5 in a kindergarten program in a high-performing suburban…

  17. Extracellular voltage threshold settings can be tuned for optimal encoding of movement and stimulus parameters

    NASA Astrophysics Data System (ADS)

    Oby, Emily R.; Perel, Sagi; Sadtler, Patrick T.; Ruff, Douglas A.; Mischel, Jessica L.; Montez, David F.; Cohen, Marlene R.; Batista, Aaron P.; Chase, Steven M.

    2016-06-01

    Objective. A traditional goal of neural recording with extracellular electrodes is to isolate action potential waveforms of an individual neuron. Recently, in brain–computer interfaces (BCIs), it has been recognized that threshold crossing events of the voltage waveform also convey rich information. To date, the threshold for detecting threshold crossings has been selected to preserve single-neuron isolation. However, the optimal threshold for single-neuron identification is not necessarily the optimal threshold for information extraction. Here we introduce a procedure to determine the best threshold for extracting information from extracellular recordings. We apply this procedure in two distinct contexts: the encoding of kinematic parameters from neural activity in primary motor cortex (M1), and visual stimulus parameters from neural activity in primary visual cortex (V1). Approach. We record extracellularly from multi-electrode arrays implanted in M1 or V1 in monkeys. Then, we systematically sweep the voltage detection threshold and quantify the information conveyed by the corresponding threshold crossings. Main Results. The optimal threshold depends on the desired information. In M1, velocity is optimally encoded at higher thresholds than speed; in both cases the optimal thresholds are lower than are typically used in BCI applications. In V1, information about the orientation of a visual stimulus is optimally encoded at higher thresholds than is visual contrast. A conceptual model explains these results as a consequence of cortical topography. Significance. How neural signals are processed impacts the information that can be extracted from them. Both the type and quality of information contained in threshold crossings depend on the threshold setting. There is more information available in these signals than is typically extracted. Adjusting the detection threshold to the parameter of interest in a BCI context should improve our ability to decode motor intent

  18. Supplementary motor area and primary auditory cortex activation in an expert break-dancer during the kinesthetic motor imagery of dance to music.

    PubMed

    Olshansky, Michael P; Bar, Rachel J; Fogarty, Mary; DeSouza, Joseph F X

    2015-01-01

    The current study used functional magnetic resonance imaging to examine the neural activity of an expert dancer with 35 years of break-dancing experience during the kinesthetic motor imagery (KMI) of dance accompanied by highly familiar and unfamiliar music. The goal of this study was to examine the effect of musical familiarity on neural activity underlying KMI within a highly experienced dancer. In order to investigate this in both primary sensory and motor planning cortical areas, we examined the effects of music familiarity on the primary auditory cortex [Heschl's gyrus (HG)] and the supplementary motor area (SMA). Our findings reveal reduced HG activity and greater SMA activity during imagined dance to familiar music compared to unfamiliar music. We propose that one's internal representations of dance moves are influenced by auditory stimuli and may be specific to a dance style and the music accompanying it. PMID:25301352

  19. Chronic hyperammonemia alters the circadian rhythms of corticosteroid hormone levels and of motor activity in rats.

    PubMed

    Ahabrach, Hanan; Piedrafita, Blanca; Ayad, Abdelmalik; El Mlili, Nisrin; Errami, Mohammed; Felipo, Vicente; Llansola, Marta

    2010-05-15

    Patients with liver cirrhosis may present hepatic encephalopathy with a wide range of neurological disturbances and alterations in sleep quality and in the sleep-wake circadian rhythm. Hyperammonemia is a main contributor to the neurological alterations in hepatic encephalopathy. We have assessed, in an animal model of chronic hyperammonemia without liver failure, the effects of hyperammonemia per se on the circadian rhythms of motor activity, temperature, and plasma levels of adrenal corticosteroid hormones. Chronic hyperammonemia alters the circadian rhythms of locomotor activity and of cortisol and corticosterone levels in blood. Different types of motor activity are affected differentially. Hyperammonemia significantly alters the rhythm of spontaneous ambulatory activity, reducing strongly ambulatory counts and slightly average velocity during the night (the active phase) but not during the day, resulting in altered circadian rhythms. In contrast, hyperammonemia did not affect wheel running at all, indicating that it affects spontaneous but not voluntary activity. Vertical activity was affected only very slightly, indicating that hyperammonemia does not induce anxiety. Hyperammonemia abolished completely the circadian rhythm of corticosteroid hormones in plasma, completely eliminating the peaks of cortisol and corticosterone present in control rats at the start of the dark period. The data reported show that chronic hyperammonemia, similar to that present in patients with liver cirrhosis, alters the circadian rhythms of corticosteroid hormones and of motor activity. This suggests that hyperammonemia would be a relevant contributor to the alterations in corticosteroid hormones and in circadian rhythms in patients with liver cirrhosis. PMID:19998493

  20. Distinct parameters of the basophil activation test reflect the severity and threshold of allergic reactions to peanut

    PubMed Central

    Santos, Alexandra F.; Du Toit, George; Douiri, Abdel; Radulovic, Suzana; Stephens, Alick; Turcanu, Victor; Lack, Gideon

    2015-01-01

    Background The management of peanut allergy relies on allergen avoidance and epinephrine autoinjector for rescue treatment in patients at risk of anaphylaxis. Biomarkers of severity and threshold of allergic reactions to peanut could significantly improve the care for patients with peanut allergy. Objective We sought to assess the utility of the basophil activation test (BAT) to predict the severity and threshold of reactivity to peanut during oral food challenges (OFCs). Methods The severity of the allergic reaction and the threshold dose during OFCs to peanut were determined. Skin prick tests, measurements of specific IgE to peanut and its components, and BATs to peanut were performed on the day of the challenge. Results Of the 124 children submitted to OFCs to peanut, 52 (median age, 5 years) reacted with clinical symptoms that ranged from mild oral symptoms to anaphylaxis. Severe reactions occurred in 41% of cases, and 57% reacted to 0.1 g or less of peanut protein. The ratio of the percentage of CD63+ basophils after stimulation with peanut and after stimulation with anti-IgE (CD63 peanut/anti-IgE) was independently associated with severity (P = .001), whereas the basophil allergen threshold sensitivity CD-sens (1/EC50 × 100, where EC50 is half maximal effective concentration) value was independently associated with the threshold (P = .020) of allergic reactions to peanut during OFCs. Patients with CD63 peanut/anti-IgE levels of 1.3 or greater had an increased risk of severe reactions (relative risk, 3.4; 95% CI, 1.8-6.2). Patients with a CD-sens value of 84 or greater had an increased risk of reacting to 0.1 g or less of peanut protein (relative risk, 1.9; 95% CI, 1.3-2.8). Conclusions Basophil reactivity is associated with severity and basophil sensitivity is associated with the threshold of allergic reactions to peanut. CD63 peanut/anti-IgE and CD-sens values can be used to estimate the severity and threshold of allergic reactions during OFCs. PMID

  1. Changing ideas about others' intentions: updating prior expectations tunes activity in the human motor system.

    PubMed

    Jacquet, Pierre O; Roy, Alice C; Chambon, Valérian; Borghi, Anna M; Salemme, Roméo; Farnè, Alessandro; Reilly, Karen T

    2016-01-01

    Predicting intentions from observing another agent's behaviours is often thought to depend on motor resonance - i.e., the motor system's response to a perceived movement by the activation of its stored motor counterpart, but observers might also rely on prior expectations, especially when actions take place in perceptually uncertain situations. Here we assessed motor resonance during an action prediction task using transcranial magnetic stimulation to probe corticospinal excitability (CSE) and report that experimentally-induced updates in observers' prior expectations modulate CSE when predictions are made under situations of perceptual uncertainty. We show that prior expectations are updated on the basis of both biomechanical and probabilistic prior information and that the magnitude of the CSE modulation observed across participants is explained by the magnitude of change in their prior expectations. These findings provide the first evidence that when observers predict others' intentions, motor resonance mechanisms adapt to changes in their prior expectations. We propose that this adaptive adjustment might reflect a regulatory control mechanism that shares some similarities with that observed during action selection. Such a mechanism could help arbitrate the competition between biomechanical and probabilistic prior information when appropriate for prediction. PMID:27243157

  2. Changing ideas about others’ intentions: updating prior expectations tunes activity in the human motor system

    PubMed Central

    Jacquet, Pierre O.; Roy, Alice C.; Chambon, Valérian; Borghi, Anna M.; Salemme, Roméo; Farnè, Alessandro; Reilly, Karen T.

    2016-01-01

    Predicting intentions from observing another agent’s behaviours is often thought to depend on motor resonance – i.e., the motor system’s response to a perceived movement by the activation of its stored motor counterpart, but observers might also rely on prior expectations, especially when actions take place in perceptually uncertain situations. Here we assessed motor resonance during an action prediction task using transcranial magnetic stimulation to probe corticospinal excitability (CSE) and report that experimentally-induced updates in observers’ prior expectations modulate CSE when predictions are made under situations of perceptual uncertainty. We show that prior expectations are updated on the basis of both biomechanical and probabilistic prior information and that the magnitude of the CSE modulation observed across participants is explained by the magnitude of change in their prior expectations. These findings provide the first evidence that when observers predict others’ intentions, motor resonance mechanisms adapt to changes in their prior expectations. We propose that this adaptive adjustment might reflect a regulatory control mechanism that shares some similarities with that observed during action selection. Such a mechanism could help arbitrate the competition between biomechanical and probabilistic prior information when appropriate for prediction. PMID:27243157

  3. Patterns of motor activity in the isolated nerve cord of the octopus arm.

    PubMed

    Gutfreund, Yoram; Matzner, Henry; Flash, Tamar; Hochner, Binyamin

    2006-12-01

    The extremely flexible octopus arm provides a unique opportunity for studying movement control in a highly redundant motor system. We describe a novel preparation that allows analysis of the peripheral nervous system of the octopus arm and its interaction with the muscular and mechanosensory elements of the arm's intrinsic muscular system. First we examined the synaptic responses in muscle fibers to identify the motor pathways from the axial nerve cord of the arm to the surrounding musculature. We show that the motor axons project to the muscles via nerve roots originating laterally from the arm nerve cord. The motor field of each nerve is limited to the region where the nerve enters the arm musculature. The same roots also carry afferent mechanosensory information from the intrinsic muscle to the axial nerve cord. Next, we characterized the pattern of activity generated in the dorsal roots by electrically stimulating the axial nerve cord. The evoked activity, although far reaching and long lasting, cannot alone account for the arm extension movements generated by similar electrical stimulation. The mismatch between patterns of activity in the isolated cord and in an intact arm may stem from the involvement of mechanosensory feedback in natural arm extension. PMID:17179381

  4. Dynamic reorganization of neural activity in motor cortex during new sequence production.

    PubMed

    Lu, Xiaofeng; Ashe, James

    2015-09-01

    Although previous studies have shown that primary motor cortex (M1) neurons are modulated during the performance of a sequence of movements, it is not known how this neural activity in the M1 reorganizes during new learning of sequence-dependent motor skills. Here we trained monkeys to move to each of four spatial targets to produce multiple distinct sequences of movements in which the spatial organization of the targets determined uniquely the serial order of the movements. After the monkeys memorized the sequences, we changed one element of these over-practised sequences and the subjects were required to learn the new sequence through trial and error. When one element in an over-learned four-element sequence was changed, the sequence-specific neural activity was totally disrupted, but relatively minor changes in the direction-specific activity were observed. The data suggest that sequential motor skills are represented within M1 in the context of the complete sequential behavior rather than as a series of single consecutive movements; and sequence-specific neurons in the M1 are involved in new learning of sequence by using memorized knowledge to acquire complex motor skill efficiently. PMID:26202600

  5. Human movements and abstract motion displays activate different processes in the observer's motor system.

    PubMed

    Agosta, Sara; Battelli, Lorella; Casile, Antonino

    2016-04-15

    Brain imaging studies have shown that observation of both bodily movements and abstract motion displays complying with human kinematics activate the observer's motor cortex. However, it is unknown whether the same processes are active in the two conditions. Here, we addressed this issue using transcranial magnetic stimulation (TMS) to directly compare cortico-spinal excitability during observation of actions and motion stimuli that complied with or violated normal human kinematics. We found that kinematics significantly modulated the motor-evoked potentials (MEPs) produced by TMS during observation of both human and abstract motion stimuli. However, only the temporal unfolding of cortico-spinal excitability during observation of human movements significantly correlated with instantaneous stimulus velocity. This correlation was present for normal movements and also for a subset of the movements having unnatural kinematics. Furthermore, bodily movements for which we found no correlation between MEPs and stimulus velocity produced significantly higher MEPs. Our novel results suggest a dissociation in how human movements and abstract motion displays engage the observer's motor system. Specifically, while both stimulus types significantly activate the observer's motor cortex, only bodily movements produce patterns of cortico-spinal excitability that closely follow the velocity profile of the observed movement. This internal "re-enactment" of observed bodily movements seems to be only partially attuned to normal human kinematics. PMID:26854559

  6. Increased activity in frontal motor cortex compensates impaired speech perception in older adults

    PubMed Central

    Du, Yi; Buchsbaum, Bradley R.; Grady, Cheryl L.; Alain, Claude

    2016-01-01

    Understanding speech in noisy environments is challenging, especially for seniors. Although evidence suggests that older adults increasingly recruit prefrontal cortices to offset reduced periphery and central auditory processing, the brain mechanisms underlying such compensation remain elusive. Here we show that relative to young adults, older adults show higher activation of frontal speech motor areas as measured by functional MRI during a syllable identification task at varying signal-to-noise ratios. This increased activity correlates with improved speech discrimination performance in older adults. Multivoxel pattern classification reveals that despite an overall phoneme dedifferentiation, older adults show greater specificity of phoneme representations in frontal articulatory regions than auditory regions. Moreover, older adults with stronger frontal activity have higher phoneme specificity in frontal and auditory regions. Thus, preserved phoneme specificity and upregulation of activity in speech motor regions provide a means of compensation in older adults for decoding impoverished speech representations in adverse listening conditions. PMID:27483187

  7. A simple but efficient voice activity detection algorithm through Hilbert transform and dynamic threshold for speech pathologies

    NASA Astrophysics Data System (ADS)

    Ortiz P., D.; Villa, Luisa F.; Salazar, Carlos; Quintero, O. L.

    2016-04-01

    A simple but efficient voice activity detector based on the Hilbert transform and a dynamic threshold is presented to be used on the pre-processing of audio signals. The algorithm to define the dynamic threshold is a modification of a convex combination found in literature. This scheme allows the detection of prosodic and silence segments on a speech in presence of non-ideal conditions like a spectral overlapped noise. The present work shows preliminary results over a database built with some political speech. The tests were performed adding artificial noise to natural noises over the audio signals, and some algorithms are compared. Results will be extrapolated to the field of adaptive filtering on monophonic signals and the analysis of speech pathologies on futures works.

  8. Sleep and duodenal motor activity in patients with severe non-ulcer dyspepsia.

    PubMed Central

    David, D; Mertz, H; Fefer, L; Sytnik, B; Raeen, H; Niazi, N; Kodner, A; Mayer, E A

    1994-01-01

    The prevalence of sleep disturbances was studied in patients with severe non-ulcer dyspepsia. It was also considered if the change in sleep pattern was associated with changes in the rhythmic fasting motor activity of the gastrointestinal tract, and if motor events correlate with the patient's symptoms. Motor activity in the duodenum was monitored over a 24 hour period under freely ambulatory conditions in 10 healthy controls and in 10 patients with severe non-ulcer dyspepsia using a transnasally placed catheter with six solid state pressure transducers connected to a digital data logging device. Symptoms and sleep disturbance were assessed by questionnaire and diary. Based on their symptoms, the patients were separated into two groups: those with dyspepsia symptoms only (non-ulcer dyspepsia; n = 5) and those with dyspepsia and additional functional symptoms thought to arise from the lower gastrointestinal tract (non-ulcer dyspepsia+irritable bowel syndrome; n = 5). When compared with either the control or the non-ulcer dyspepsia+irritable bowel syndrome group, non-ulcer dyspepsia patients had a considerably decreased number of migrating motor complexes during the nocturnal period (0.7 v 4.6), a decreased percentage of nocturnal phase I (5.2% v 78.0%), and an increased percentage of the nocturnal period in phase II (94% v 15.4%). Patients with non-ulcer dyspepsia+irritable bowel syndrome were not different from normal controls. Four of the non-ulcer dyspepsia patients and all of the non-ulcer dyspepsia+irritable bowel syndrome patients reported difficulties with sleep. Clusters of high amplitude tonic and phasic activity, not accompanied by subjective reports of discomfort were noted in several patients in both groups during the study. In eight of 10 patients, abdominal pain was reported during normal motor activity, while in one patient, pain correlated with phase III of the migrating motor complex. In contrast with previous reports in patients with irritable

  9. Subthalamic nucleus activity in the awake hemiparkinsonian rat: relationships with motor and cognitive networks.

    PubMed

    Delaville, Claire; McCoy, Alex J; Gerber, Colin M; Cruz, Ana V; Walters, Judith R

    2015-04-29

    Oscillatory activity in both beta and gamma ranges has been recorded in the subthalamic nucleus (STN) of Parkinson's disease (PD) patients and linked to motor function, with beta activity considered antikinetic, and gamma activity, prokinetic. However, the extent to which nonmotor networks contribute to this activity is unclear. This study uses hemiparkinsonian rats performing a treadmill walking task to compare synchronized STN local field potential (LFP) activity with activity in motor cortex (MCx) and medial prefrontal cortex (mPFC), areas involved in motor and cognitive processes, respectively. Data show increases in STN and MCx 29-36 Hz LFP spectral power and coherence after dopamine depletion, which are reduced by apomorphine and levodopa treatments. In contrast, recordings from mPFC 3 weeks after dopamine depletion failed to show peaks in 29-36 Hz LFP power. However, mPFC and STN both showed peaks in the 45-55 Hz frequency range in LFP power and coherence during walking before and 21 days after dopamine depletion. Interestingly, power in this low gamma range was transiently reduced in both mPFC and STN after dopamine depletion but recovered by day 21. In contrast to the 45-55 Hz activity, the amplitude of the exaggerated 29-36 Hz rhythm in the STN was modulated by paw movement. Furthermore, as in PD patients, after dopamine treatment a third band (high gamma) emerged in the lesioned hemisphere. The results suggest that STN integrates activity from both motor and cognitive networks in a manner that varies with frequency, behavioral state, and the integrity of the dopamine system. PMID:25926466

  10. Subthalamic Nucleus Activity in the Awake Hemiparkinsonian Rat: Relationships with Motor and Cognitive Networks

    PubMed Central

    Delaville, Claire; McCoy, Alex J.; Gerber, Colin M.; Cruz, Ana V.

    2015-01-01

    Oscillatory activity in both beta and gamma ranges has been recorded in the subthalamic nucleus (STN) of Parkinson's disease (PD) patients and linked to motor function, with beta activity considered antikinetic, and gamma activity, prokinetic. However, the extent to which nonmotor networks contribute to this activity is unclear. This study uses hemiparkinsonian rats performing a treadmill walking task to compare synchronized STN local field potential (LFP) activity with activity in motor cortex (MCx) and medial prefrontal cortex (mPFC), areas involved in motor and cognitive processes, respectively. Data show increases in STN and MCx 29–36 Hz LFP spectral power and coherence after dopamine depletion, which are reduced by apomorphine and levodopa treatments. In contrast, recordings from mPFC 3 weeks after dopamine depletion failed to show peaks in 29–36 Hz LFP power. However, mPFC and STN both showed peaks in the 45–55 Hz frequency range in LFP power and coherence during walking before and 21 days after dopamine depletion. Interestingly, power in this low gamma range was transiently reduced in both mPFC and STN after dopamine depletion but recovered by day 21. In contrast to the 45–55 Hz activity, the amplitude of the exaggerated 29–36 Hz rhythm in the STN was modulated by paw movement. Furthermore, as in PD patients, after dopamine treatment a third band (high gamma) emerged in the lesioned hemisphere. The results suggest that STN integrates activity from both motor and cognitive networks in a manner that varies with frequency, behavioral state, and the integrity of the dopamine system. PMID:25926466

  11. Effect of light on the activity of motor cortex neurons during locomotion

    PubMed Central

    Armer, Madison C.; Nilaweera, Wijitha U.; Rivers, Trevor J.; Dasgupta, Namrata M.; Beloozerova, Irina N.

    2013-01-01

    The motor cortex plays a critical role in accurate visually guided movements such as reaching and target stepping. However, the manner in which vision influences the movement-related activity of neurons in the motor cortex is not well understood. In this study we have investigated how the locomotion-related activity of neurons in the motor cortex is modified when subjects switch between walking in the darkness and in light. Three adult cats were trained to walk through corridors of an experimental chamber for a food reward. On randomly selected trials, lights were extinguished for approximately four seconds when the cat was in a straight portion of the chamber's corridor. Discharges of 146 neurons from layer V of the motor cortex, including 51 pyramidal tract cells (PTNs), were recorded and compared between light and dark conditions. It was found that while cats’ movements during locomotion in light and darkness were similar (as judged from the analysis of three-dimensional limb kinematics and the activity of limb muscles), the firing behavior of 49% (71/146) of neurons was different between the two walking conditions. This included differences in the mean discharge rate (19%, 28/146 of neurons), depth of stride-related frequency modulation (24%, 32/131), duration of the period of elevated firing ([PEF], 19%, 25/131), and number of PEFs among stride-related neurons (26%, 34/131). 20% of responding neurons exhibited more than one type of change. We conclude that visual input plays a very significant role in determining neuronal activity in the motor cortex during locomotion by altering one, or occasionally multiple, parameters of locomotion-related discharges of its neurons. PMID:23680161

  12. Patterns of regional brain activation associated with different forms of motor learning.

    PubMed

    Ghilardi, M; Ghez, C; Dhawan, V; Moeller, J; Mentis, M; Nakamura, T; Antonini, A; Eidelberg, D

    2000-07-14

    To examine the variations in regional cerebral blood flow during execution and learning of reaching movements, we employed a family of kinematically and dynamically controlled motor tasks in which cognitive, mnemonic and executive features of performance were differentiated and characterized quantitatively. During 15O-labeled water positron emission tomography (PET) scans, twelve right-handed subjects moved their dominant hand on a digitizing tablet from a central location to equidistant targets displayed with a cursor on a computer screen in synchrony with a tone. In the preceding week, all subjects practiced three motor tasks: 1) movements to a predictable sequence of targets; 2) learning of new visuomotor transformations in which screen cursor motion was rotated by 30 degrees -60 degrees; 3) learning new target sequences by trial and error, by using previously acquired routines in a task placing heavy load on spatial working memory. The control condition was observing screen and audio displays. Subtraction images were analyzed with Statistical Parametric Mapping to identify significant brain activation foci. Execution of predictable sequences was characterized by a modest decrease in movement time and spatial error. The underlying pattern of activation involved primary motor and sensory areas, cerebellum, basal ganglia. Adaptation to a rotated reference frame, a form of procedural learning, was associated with decrease in the imposed directional bias. This task was associated with activation in the right posterior parietal cortex. New sequences were learned explicitly. Significant activation was found in dorsolateral prefrontal and anterior cingulate cortices. In this study, we have introduced a series of flexible motor tasks with similar kinematic characteristics and different spatial attributes. These tasks can be used to assess specific aspects of motor learning with imaging in health and disease. PMID:10882792

  13. Analysis of different tumor volume thresholds of insignificant prostate cancer and their implications for active surveillance patient selection and monitoring

    PubMed Central

    Lee, Dong Hoon; Koo, Kyo Chul; Lee, Seung Hwan; Rha, Koon Ho; Choi, Young Deuk; Hong, Sung Joon; Chung, Byung Ha

    2014-01-01

    Purpose: We compared oncological outcomes according to tumor volume (TV) thresholds defining both classical and updated insignificant prostate cancer (IPC), since the TV threshold can be used as clinical parameter for active surveillance. Methods: Between 2001 and 2012, we retrospectively analyzed 331 organ-confined prostate cancer patients who had preoperative Gleason score 6, preoperative PSA under 10 ng/mL and pathologic TV less than 1.3 mL. Among them, 81 of 331 (24.5%) had Gleason grade 4/5 disease postoperatively. Patients were stratified into two groups: (1) TV less than 0.5 mL, using the classical definition; and (2) TV between 0.5 mL and 1.3 mL, using the range of updated definition. We compared biochemical recurrence (BCR)-free survival and identified independent predictors of BCR in each group. Results: Group 2 had more Gleason grade 4/5 disease than group 1 (P<0.001). On multivariate analysis, Gleason grade 4/5 disease was not associated with BCR in group 1 (P=0.132). However, it was an independent predictor for BCR in group 2 (P=0.042). BCR-free survival were not significantly different according to the presence of Gleason grade 4/5 disease in group 1 (P=0.115). However, in group 2, it was significantly different according to the presence of Gleason grade 4/5 disease (P=0.041). Conclusions: Although the TV thresholds of the two definitions of IPC vary only slightly, this difference was enough to result in different clinical course if Gleason grade 4/5 disease was present. Therefore, the updated IPC TV threshold should be carefully applied as clinical parameter for active surveillance. PMID:25032193

  14. Active Transport of Nanomaterials Using Motor Proteins -Final Report

    SciTech Connect

    Hess, Henry

    2005-09-01

    During the six months of funding we have focused first on the completion of the research begun at the University of Washington in the previous funding cycle. Specifically, we developed a method to polymerize oriented networks of microtubules on lithographically patterned surfaces (M.S. thesis Robert Doot). The properties of active transport have been studied detail, yielding insights into the dispersion mechanisms (Nitta et al.). The assembly of multifunctional structures with a microtubule core has been investigated (Ramachandran et al.). Isaac Luria (B.S. in physics, U. of Florida 2005) worked on the directed assembly of nanoscale, non-equilibrium structures as a summer intern. He is now a graduate student in my group at the University of Florida. T. Nitta and H. Hess: Dispersion in Active Transport by Kinesin-Powered Molecular Shuttles, Nano Letters, 5, 1337-1342 (2005) S. Ramachandran, K.-H. Ernst, G. D. Bachand, V. Vogel, H. Hess*: Selective Loading of Kinesin-Powered Molecular Shuttles with Protein Cargo and its Application to Biosensing, submitted to Small (2005)

  15. Cerebral cortical activity associated with non-experts' most accurate motor performance.

    PubMed

    Dyke, Ford; Godwin, Maurice M; Goel, Paras; Rehm, Jared; Rietschel, Jeremy C; Hunt, Carly A; Miller, Matthew W

    2014-10-01

    This study's specific aim was to determine if non-experts' most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation. To assess this, EEG was recorded from non-expert golfers executing putts; EEG spectral power and coherence were calculated for the epoch preceding putt execution; and spectral power and coherence for the five most accurate putts were contrasted with that for the five least accurate. Results revealed marked power in the theta frequency bandwidth at all cerebral cortical regions for the most accurate putts relative to the least accurate, and considerable power in the low-beta frequency bandwidth at the left temporal region for the most accurate compared to the least. As theta power is associated with working memory and low-beta power at the left temporal region with verbal analysis, results suggest non-experts' most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation. PMID:25058623

  16. Effects of the potassium channel blocking dendrotoxins on acetylcholine release and motor nerve terminal activity.

    PubMed

    Anderson, A J; Harvey, A L

    1988-01-01

    1. The effects of the K+ channel blocking toxins, the dendrotoxins, on neuromuscular transmission and motor nerve terminal activity were assessed on frog cutaneous pectoris, mouse diaphragm and mouse triangularis sterni nerve-muscle preparations. Endplate potentials (e.p.ps) and miniature e.p.ps were recorded with intracellular microelectrodes, and nerve terminal spikes were recorded with extracellular electrodes placed in the perineural sheaths of motor nerves. 2. Dendrotoxin from green mamba (Dendroaspis angusticeps) venom and toxin I from black mamba (D. polylepis) venom increased the amplitude of e.p.ps by increasing quantal content, and also induced repetitive e.p.ps. 3. Perineural recordings revealed that dendrotoxins could decrease the component of the waveform associated with K+ currents at the nerve terminals, and induce repetitive activation of nerve terminals. 4. In frog motor nerves, dendrotoxins are known to block the fast f1 component of the K+ current at nodes of Ranvier. Blockade of a similar component of the K+ current at motor nerve terminals may be responsible for the effects of these toxins on neuromuscular transmission. 5. Similar conclusions can be drawn from the results obtained from mouse neuromuscular junctions. PMID:2450611

  17. The effect of oral motor activity on the athletic performance of professional golfers.

    PubMed

    Ringhof, Steffen; Hellmann, Daniel; Meier, Florian; Etz, Eike; Schindler, Hans J; Stein, Thorsten

    2015-01-01

    Human motor control is based on complex sensorimotor processes. Recent research has shown that neuromuscular activity of the craniomandibular system (CMS) might affect human motor control. In particular, improvements in postural stability and muscle strength have been observed as a result of voluntary jaw clenching. Potential benefits of jaw aligning appliances on muscle strength and golf performance have also been described. These reports are highly contradictory, however, and the oral motor task performed is often unclear. The purpose of our study was, therefore, to investigate the effect of submaximum biting on golf performance via shot precision and shot length over three different distances. Participants were 14 male professional golfers - seven with sleep bruxism and seven without - randomly performing golf shots over 60m, 160m, or driving distance while either biting on an oral splint or biting on their teeth; habitual jaw position served as the control condition. Statistical analysis revealed that oral motor activity did not systematically affect golf performance in respect of shot precision or shot length for 60m, 160 m, or driving distance. These findings were reinforced by impact variables such as club head speed and ball speed, which were also not indicative of significant effects. The results thus showed that the strength improvements and stabilizing effects described previously are, apparently, not transferable to such coordination-demanding sports as golf. This could be due to the divergent motor demands associated with postural control and muscle strength on the one hand and the complex coordination of a golf swing on the other. Interestingly, subjects without sleep bruxism performed significantly better at the short distance (60 m) than those with bruxism. Because of the multifactorial etiology of parafunctional CMS activity, conclusions about the need for dental treatment to improve sports performance are, however, completely unwarranted. PMID

  18. The effect of oral motor activity on the athletic performance of professional golfers

    PubMed Central

    Ringhof, Steffen; Hellmann, Daniel; Meier, Florian; Etz, Eike; Schindler, Hans J.; Stein, Thorsten

    2015-01-01

    Human motor control is based on complex sensorimotor processes. Recent research has shown that neuromuscular activity of the craniomandibular system (CMS) might affect human motor control. In particular, improvements in postural stability and muscle strength have been observed as a result of voluntary jaw clenching. Potential benefits of jaw aligning appliances on muscle strength and golf performance have also been described. These reports are highly contradictory, however, and the oral motor task performed is often unclear. The purpose of our study was, therefore, to investigate the effect of submaximum biting on golf performance via shot precision and shot length over three different distances. Participants were 14 male professional golfers – seven with sleep bruxism and seven without – randomly performing golf shots over 60m, 160m, or driving distance while either biting on an oral splint or biting on their teeth; habitual jaw position served as the control condition. Statistical analysis revealed that oral motor activity did not systematically affect golf performance in respect of shot precision or shot length for 60m, 160 m, or driving distance. These findings were reinforced by impact variables such as club head speed and ball speed, which were also not indicative of significant effects. The results thus showed that the strength improvements and stabilizing effects described previously are, apparently, not transferable to such coordination-demanding sports as golf. This could be due to the divergent motor demands associated with postural control and muscle strength on the one hand and the complex coordination of a golf swing on the other. Interestingly, subjects without sleep bruxism performed significantly better at the short distance (60 m) than those with bruxism. Because of the multifactorial etiology of parafunctional CMS activity, conclusions about the need for dental treatment to improve sports performance are, however, completely unwarranted. PMID

  19. The effects of sleep, wake activity and time-on-task on offline motor sequence learning.

    PubMed

    Landry, Shane; Anderson, Clare; Conduit, Russell

    2016-01-01

    While intervening sleep promotes the consolidation of memory, it is well established that cognitive interference from competing stimuli can impede memory retention. The current study examined changes in motor skill learning across periods of wakefulness with and without competing stimuli, and periods of sleep with and without disruption from external stimuli. A napping study design was adopted where participants (N=44) either had (1) a 30min nap composed of Non-Rapid Eye Movement (NREM) sleep, (2) 30min NREM nap fragmented by audio tone induced arousals, (3) 45min of quiet wakefulness, or (4) 45min of active wakefulness. Measures of subjective sleepiness (KSS), alertness (PVT) and motor skill learning (Sequential Finger Tapping Task, SFTT) were completed in the morning and evening to assess performance pre- and post-nap or wakefulness. Following a practice session, change in motor skill performance was measured over a 10min post training rest interval, as well as following a 7h morning to evening interval comprising one of the four study conditions. A significant offline enhancement in motor task performance (13-23%) was observed following 10min of rest in all conditions. Following the long delay with the intervening nap/wake condition, there were no further offline gains or losses in performance in any sleep (uninterrupted/fragmented) or wake (quiet/active) condition. The current findings suggest that after controlling for offline gains in performance that occur after a brief rest and likely to due to the dissipation of fatigue, the subsequent effect of an intervening sleep or wake period on motor skill consolidation is not significant. Consistent with this null result, the impact of disrupting the sleep episode or manipulating activity during intervening wake also appears to be negligible. PMID:26655281

  20. Regional vulnerability of the hippocampus to repeated motor activity deprivation.

    PubMed

    Faraji, Jamshid; Soltanpour, Nabiollah; Moeeini, Reza; Hosseini, Seyed Abedin; Pakdel, Shiva; Moharrerie, Alireza; Arjang, Kaveh; Soltanpour, Nasrin; Metz, Gerlinde A S

    2016-03-15

    Spontaneous vertical and horizontal exploratory movements are integral components of rodent behavior. Little is known, however, about the structural and functional consequences of restricted spontaneous exploration. Here, we report two experiments to probe whether restriction in vertical activity (rearing) in rats could induce neuro-hormonal and behavioral disturbances. Rearing movements in rats were deprived for 3h/day for 30 consecutive days by placing the animal into a circular tunnel task. Rats temporarily deprived of rearing behavior showed elevated plasma corticosterone levels but no detectable psychological distress and/or anxiety-related behavior within an elevated plus maze. However, rats emitted a greater number of 22-kHz ultrasonic vocalizations and spent significantly more time vocalizing than controls when deprived of their rearing behavior. Despite intact spatial performance within wet- and dry-land spatial tasks, rearing-deprived rats also exhibited a significant alteration in search strategies within both spatial tasks along with reduced volume and neuron number in the hippocampal subregion CA2. These data suggest a new approach to test the importance of free exploratory behavior in endocrine and structural manifestations. The results support a central role of the CA2 in spontaneous exploratory behavior and vulnerability to psychological stress. PMID:26723539

  1. Nano-engineered living bacterial motors for active microfluidic mixing.

    PubMed

    Al-Fandi, M; Jaradat, M A K; Fandi, K; Beech, J P; Tegenfeldt, J O; Yih, T C

    2010-09-01

    Active micromixers with rotating elements are attractive microfluidic actuators in many applications because of their mixing ability at a short distance. However, miniaturising the impeller design poses technical challenges including the fabrication and driving means. As a possible solution inspired by macro magnetic bar-stirrers, this study proposes the use of tethered, rotating bacteria as mixing elements. A tethered cell is a genetically engineered, harmless Escherichia coli (E. coli) attached to a surface by a single, shortened flagellum. The tethered flagellum acts as a pivot around which the entire cell body smoothly rotates. Videomicroscopy, image analysis and computational fluid dynamics (CFD) are utilised to demonstrate a proof-of-concept for the micro mixing process. Flow visualisation experiments show that a approximately 3 microm long tethered E. coli rotating at approximately 240 rpm can circulate a 1 microm polystyrene bead in the adjacent area at an average speed of nearly 4 microm/s. The Peclet (Peb) number for the stirred bead is evaluated to approximately 4. CFD simulations show that the rotary motion of a tethered E. coli rotating at 240 rpm can generate fluid velocities, up to 37 microm/s bordering the cell envelop. Based on these simulations, the Strouhal number (St) is calculated to about 2. This hybrid bio-inorganic micromxer could be used as a local, disposable mixer. PMID:20726672

  2. The Over-expression of the Plastidial Transglutaminase from Maize in Arabidopsis Increases the Activation Threshold of Photoprotection

    PubMed Central

    Ioannidis, Nikolaos E.; Malliarakis, Dimitris; Torné, Josep M.; Santos, Mireya; Kotzabasis, Kiriakos

    2016-01-01

    Plastidial transglutaminase is one of the most promising enzymes in chloroplast bioenergetics due to its link with polyamine pathways and the cross talk with signals such as Ca2+ and GTP. Here, we show the effect of the increase of transglutaminase activity in Arabidopsis by using genetic transformation techniques. These lines fulfill their biological cycle normally (normal growth in soil, production of viable seeds) and show a relatively mild increase in transglutaminase activity (127%). These overexpressors of transglutaminase (OE TGase) have an extended stroma thylakoid network (71% higher number of PSIIβ centers), similar chlorophyll content (-4%), higher linear electron flow (+13%), and higher threshold of photoprotection activation (∼100%). On the other hand OE TGase showed a reduced maximum photochemistry of PSII (-6.5%), a smaller antenna per photosystem II (-25%), a lower photoprotective “energization” quenching or qE (-77% at 490 μmol photons m-2 s-1) due to a higher threshold of qE activation and slightly lower light induced proton motive force (-17%). The role of the polyamines and of the transglutaminase in the regulation of chemiosmosis and photoprotection in chloroplasts is discussed. PMID:27242838

  3. The Over-expression of the Plastidial Transglutaminase from Maize in Arabidopsis Increases the Activation Threshold of Photoprotection.

    PubMed

    Ioannidis, Nikolaos E; Malliarakis, Dimitris; Torné, Josep M; Santos, Mireya; Kotzabasis, Kiriakos

    2016-01-01

    Plastidial transglutaminase is one of the most promising enzymes in chloroplast bioenergetics due to its link with polyamine pathways and the cross talk with signals such as Ca(2+) and GTP. Here, we show the effect of the increase of transglutaminase activity in Arabidopsis by using genetic transformation techniques. These lines fulfill their biological cycle normally (normal growth in soil, production of viable seeds) and show a relatively mild increase in transglutaminase activity (127%). These overexpressors of transglutaminase (OE TGase) have an extended stroma thylakoid network (71% higher number of PSIIβ centers), similar chlorophyll content (-4%), higher linear electron flow (+13%), and higher threshold of photoprotection activation (∼100%). On the other hand OE TGase showed a reduced maximum photochemistry of PSII (-6.5%), a smaller antenna per photosystem II (-25%), a lower photoprotective "energization" quenching or qE (-77% at 490 μmol photons m(-2) s(-1)) due to a higher threshold of qE activation and slightly lower light induced proton motive force (-17%). The role of the polyamines and of the transglutaminase in the regulation of chemiosmosis and photoprotection in chloroplasts is discussed. PMID:27242838

  4. [The motor activity as an age parameter of the rat (authors transl)].

    PubMed

    Hofecker, G; Kment, A; Niedermüller, H

    1978-05-01

    The motor activity as an behavioural parameter provides information about the functional state of the organism as a whole. Therefore it is an important age parameter. The results of activity measurements, however, depend strongly on the method of registration. Using 3 groups of male Sprague-Dawley rats aged 9, 15 and 29 months two methods have been tested: 1) An electronic recording: the rats were registrated in their normal cages on the Animex-Activity-Meter during the dark-phase in complete darkness. The activity measured by this method has been regarded as spontaneous activity. 2) A kinematographic method: the rats were registrated in a changed environment at constant light during the dark-phase. The activity assessed by this method has been regarded as reactive activity. Spontaneous and reactive activity show a different age dependence. For the use of the motor activity as an age parameter, both, spontaneous and reactive activity, should be assessed to get a better information about the ageing of the different functional levels of the systems governing the animal's behaviour. PMID:26274

  5. Voltage-sensitive dye imaging of primary motor cortex activity produced by ventral tegmental area stimulation.

    PubMed

    Kunori, Nobuo; Kajiwara, Riichi; Takashima, Ichiro

    2014-06-25

    The primary motor cortex (M1) receives dopaminergic projections from the ventral tegmental area (VTA) through the mesocortical dopamine pathway. However, few studies have focused on changes in M1 neuronal activity caused by VTA activation. To address this issue, we used voltage-sensitive dye imaging (VSD) to reveal the spatiotemporal dynamics of M1 activity induced by single-pulse stimulation of VTA in anesthetized rats. VSD imaging showed that brief electrical stimulation of unilateral VTA elicited a short-latency excitatory-inhibitory sequence of neuronal activity not only in the ipsilateral but also in the contralateral M1. The contralateral M1 response was not affected by pharmacological blockade of ipsilateral M1 activity, but it was completely abolished by corpus callosum transection. Although the VTA-evoked neuronal activity extended throughout the entire M1, we found the most prominent activity in the forelimb area of M1. The 6-OHDA-lesioned VTA failed to evoke M1 activity. Furthermore, both excitatory and inhibitory intact VTA-induced activity was entirely extinguished by blocking glutamate receptors in the target M1. When intracortical microstimulation of M1 was paired with VTA stimulation, the evoked forelimb muscle activity was facilitated or inhibited, depending on the interval between the two stimuli. These findings suggest that VTA neurons directly modulate the excitability of M1 neurons via fast glutamate signaling and, consequently, may control the last cortical stage of motor command processing. PMID:24966388

  6. Interactive Effects of Dorsomedial Hypothalamic Nucleus and Time-Restricted Feeding on Fractal Motor Activity Regulation.

    PubMed

    Lo, Men-Tzung; Chiang, Wei-Yin; Hsieh, Wan-Hsin; Escobar, Carolina; Buijs, Ruud M; Hu, Kun

    2016-01-01

    One evolutionary adaptation in motor activity control of animals is the anticipation of food that drives foraging under natural conditions and is mimicked in laboratory with daily scheduled food availability. Food anticipation is characterized by increased activity a few hours before the feeding period. Here we report that 2-h food availability during the normal inactive phase of rats not only increases activity levels before the feeding period but also alters the temporal organization of motor activity fluctuations over a wide range of time scales from minutes up to 24 h. We demonstrate this multiscale alteration by assessing fractal patterns in motor activity fluctuations-similar fluctuation structure at different time scales-that are robust in intact animals with ad libitum food access but are disrupted under food restriction. In addition, we show that fractal activity patterns in rats with ad libitum food access are also perturbed by lesion of the dorsomedial hypothalamic (DMH)-a neural node that is involved in food anticipatory behavior. Instead of further disrupting fractal regulation, food restriction restores the disrupted fractal patterns in these animals after the DMH lesion despite the persistence of the 24-h rhythms. This compensatory effect of food restriction is more clearly pronounced in the same animals after the additional lesion of the suprachiasmatic nucleus (SCN)-the central master clock in the circadian system that generates and orchestrates circadian rhythms in behavior and physiological functions in synchrony with day-night cycles. Moreover, all observed influences of food restriction persist even when data during the food anticipatory and feeding period are excluded. These results indicate that food restriction impacts dynamics of motor activity at different time scales across the entire circadian/daily cycle, which is likely caused by the competition between the food-induced time cue and the light-entrained circadian rhythm of the SCN. The

  7. Interactive Effects of Dorsomedial Hypothalamic Nucleus and Time-Restricted Feeding on Fractal Motor Activity Regulation

    PubMed Central

    Lo, Men-Tzung; Chiang, Wei-Yin; Hsieh, Wan-Hsin; Escobar, Carolina; Buijs, Ruud M.; Hu, Kun

    2016-01-01

    One evolutionary adaptation in motor activity control of animals is the anticipation of food that drives foraging under natural conditions and is mimicked in laboratory with daily scheduled food availability. Food anticipation is characterized by increased activity a few hours before the feeding period. Here we report that 2-h food availability during the normal inactive phase of rats not only increases activity levels before the feeding period but also alters the temporal organization of motor activity fluctuations over a wide range of time scales from minutes up to 24 h. We demonstrate this multiscale alteration by assessing fractal patterns in motor activity fluctuations—similar fluctuation structure at different time scales—that are robust in intact animals with ad libitum food access but are disrupted under food restriction. In addition, we show that fractal activity patterns in rats with ad libitum food access are also perturbed by lesion of the dorsomedial hypothalamic (DMH)—a neural node that is involved in food anticipatory behavior. Instead of further disrupting fractal regulation, food restriction restores the disrupted fractal patterns in these animals after the DMH lesion despite the persistence of the 24-h rhythms. This compensatory effect of food restriction is more clearly pronounced in the same animals after the additional lesion of the suprachiasmatic nucleus (SCN)—the central master clock in the circadian system that generates and orchestrates circadian rhythms in behavior and physiological functions in synchrony with day-night cycles. Moreover, all observed influences of food restriction persist even when data during the food anticipatory and feeding period are excluded. These results indicate that food restriction impacts dynamics of motor activity at different time scales across the entire circadian/daily cycle, which is likely caused by the competition between the food-induced time cue and the light-entrained circadian rhythm of the

  8. The method of subliminal psychodynamic activation: do individual thresholds make a difference?

    PubMed

    Malik, R; Paraherakis, A; Joseph, S; Ladd, H

    1996-12-01

    The present experiment investigated the effects of subliminal psychodynamic stimuli on anxiety as measured by heart rate. Following an anxiety-inducing task, male and female subjects were tachistoscopically shown, at their subjective thresholds, one of five subliminal stimuli, MOMMY AND I ARE ONE, DADDY AND I ARE ONE (symbiotic messages). MOMMY HAS LEFT ME (abandonment message), I AM HAPPY AND CALM (positively toned but nonsymbiotic phrase), or MYMMO NAD I REA ENO (control stimulus). It was hypothesized that men would exhibit a greater decrease in heart rate after exposure to the MOMMY stimulus than the control message. No definitive predictions were made for women. The abandonment phrase was expected to increase heart rate. A positively toned message was included to assess whether its effects would be comparable to those hypothesized for the MOMMY message. The results yielded no significant effects for stimulus or gender and so provided no support for the hypotheses. PMID:9017738

  9. Active Motor Training Has Long-term Effects on Infants' Object Exploration.

    PubMed

    Wiesen, Sarah E; Watkins, Rachel M; Needham, Amy Work

    2016-01-01

    Long-term changes in infants' behavior as a result of active motor training were studied. Thirty-two infants completed three visits to the laboratory. At the first visit, infants were 3 months old and completed an object exploration assessment. Then the experimenter demonstrated the motor training procedures appropriate for the infant's experimental condition, and parents took home custom infant mittens (either sticky or non-sticky) and a bag of lightweight toys to practice with their infants. Over the course of the following 2 weeks, infants participated in 10 sessions of either active (sticky) or passive (non-sticky) mittens training at home with their parents. Infants who participated in active mittens training wore mittens with the palms covered in Velcro, allowing them to pick up and move around small toys. Infants who participated in passive mittens training wore non-sticky mittens, and their parents moved the toys through their visual fields on their behalf. After completing the training, infants returned to the lab for the second visit. At visit two, infants participated in another object exploration assessment as well as a reaching assessment. Parents returned the training materials to the lab at the second visit, and were told not to continue any specific training regimen from this point forward. Two months later, when infants were about 5.5 months of age, they returned to the lab for a third visit. At the third visit, infants completed the same two assessments as during the second visit. The results of this study indicate that infants who participated in active motor training engaged in more sophisticated object exploration when compared to infants who received passive training. These findings are consistent with others in the literature showing that active motor training at 3 months of age facilitates the processes of object exploration and engagement. The current results and others reveal that the effects of early experience can last long after

  10. Active Motor Training Has Long-term Effects on Infants’ Object Exploration

    PubMed Central

    Wiesen, Sarah E.; Watkins, Rachel M.; Needham, Amy Work

    2016-01-01

    Long-term changes in infants’ behavior as a result of active motor training were studied. Thirty-two infants completed three visits to the laboratory. At the first visit, infants were 3 months old and completed an object exploration assessment. Then the experimenter demonstrated the motor training procedures appropriate for the infant’s experimental condition, and parents took home custom infant mittens (either sticky or non-sticky) and a bag of lightweight toys to practice with their infants. Over the course of the following 2 weeks, infants participated in 10 sessions of either active (sticky) or passive (non-sticky) mittens training at home with their parents. Infants who participated in active mittens training wore mittens with the palms covered in Velcro, allowing them to pick up and move around small toys. Infants who participated in passive mittens training wore non-sticky mittens, and their parents moved the toys through their visual fields on their behalf. After completing the training, infants returned to the lab for the second visit. At visit two, infants participated in another object exploration assessment as well as a reaching assessment. Parents returned the training materials to the lab at the second visit, and were told not to continue any specific training regimen from this point forward. Two months later, when infants were about 5.5 months of age, they returned to the lab for a third visit. At the third visit, infants completed the same two assessments as during the second visit. The results of this study indicate that infants who participated in active motor training engaged in more sophisticated object exploration when compared to infants who received passive training. These findings are consistent with others in the literature showing that active motor training at 3 months of age facilitates the processes of object exploration and engagement. The current results and others reveal that the effects of early experience can last long after

  11. Predicting brain activation patterns associated with individual lexical concepts based on five sensory-motor attributes.

    PubMed

    Fernandino, Leonardo; Humphries, Colin J; Seidenberg, Mark S; Gross, William L; Conant, Lisa L; Binder, Jeffrey R

    2015-09-01

    While major advances have been made in uncovering the neural processes underlying perceptual representations, our grasp of how the brain gives rise to conceptual knowledge remains relatively poor. Recent work has provided strong evidence that concepts rely, at least in part, on the same sensory and motor neural systems through which they were acquired, but it is still unclear whether the neural code for concept representation uses information about sensory-motor features to discriminate between concepts. In the present study, we investigate this question by asking whether an encoding model based on five semantic attributes directly related to sensory-motor experience - sound, color, visual motion, shape, and manipulation - can successfully predict patterns of brain activation elicited by individual lexical concepts. We collected ratings on the relevance of these five attributes to the meaning of 820 words, and used these ratings as predictors in a multiple regression model of the fMRI signal associated with the words in a separate group of participants. The five resulting activation maps were then combined by linear summation to predict the distributed activation pattern elicited by a novel set of 80 test words. The encoding model predicted the activation patterns elicited by the test words significantly better than chance. As expected, prediction was successful for concrete but not for abstract concepts. Comparisons between encoding models based on different combinations of attributes indicate that all five attributes contribute to the representation of concrete concepts. Consistent with embodied theories of semantics, these results show, for the first time, that the distributed activation pattern associated with a concept combines information about different sensory-motor attributes according to their respective relevance. Future research should investigate how additional features of phenomenal experience contribute to the neural representation of conceptual

  12. Body side-specific control of motor activity during turning in a walking animal

    PubMed Central

    Gruhn, Matthias; Rosenbaum, Philipp; Bockemühl, Till; Büschges, Ansgar

    2016-01-01

    Animals and humans need to move deftly and flexibly to adapt to environmental demands. Despite a large body of work on the neural control of walking in invertebrates and vertebrates alike, the mechanisms underlying the motor flexibility that is needed to adjust the motor behavior remain largely unknown. Here, we investigated optomotor-induced turning and the neuronal mechanisms underlying the differences between the leg movements of the two body sides in the stick insect Carausius morosus. We present data to show that the generation of turning kinematics in an insect are the combined result of descending unilateral commands that change the leg motor output via task-specific modifications in the processing of local sensory feedback as well as modification of the activity of local central pattern generating networks in a body-side-specific way. To our knowledge, this is the first study to demonstrate the specificity of such modifications in a defined motor task. DOI: http://dx.doi.org/10.7554/eLife.13799.001 PMID:27130731

  13. PROMOTING GROSS MOTOR SKILLS IN TODDLERS: THE ACTIVE BEGINNINGS PILOT CLUSTER RANDOMIZED TRIAL.

    PubMed

    Veldman, Sanne L C; Okely, Anthony D; Jones, Rachel A

    2015-12-01

    This study examined the feasibility, acceptability, and potential efficacy of a gross motor skill program for toddlers. An 8-wk. skills program in which children practiced three skills was implemented for 10 min. daily in two randomly designated childcare centers. Two other centers served as the control group. Recruitment and retention rates were collected for feasibility. Data on professional development, children's participation, program duration, and appropriateness of the lessons were collected for acceptability, and the Test of Gross Motor Development-2 and Get Skilled, Get Active (total of 28 points) were used to look at the potential efficacy. The participants were 60 toddlers (M age=2.5 yr., SD=0.4; n=29 boys), and the retention rate was 95%. Overall participation was 76%, and educators rated 98% of the lessons as appropriate. Compared with the control group, the intervention group showed significantly greater improvements in motor skills (p<.05, Cohen's d=1.13). This study shows that a brief intervention, which is easy to integrate on a daily basis in childcare settings, can improve motor skills among toddlers. PMID:26682608

  14. Role of GluR1 in Activity-Dependent Motor System Development

    PubMed Central

    Zhang, Lei; Schessl, Joachim; Werner, Markus; Bonnemann, Carsten; Xiong, Guoxiang; Mojsilovic-Petrovic, Jelena; Zhou, Weiguo; Cohen, Akiva; Seeburg, Peter; Misawa, Hidemi; Jayaram, Aditi; Personius, Kirkwood; Hollmann, Michael; Sprengel, Rolf

    2008-01-01

    Activity-dependent specification of neuronal architecture during early postnatal life is essential for refining the precision of communication between neurons. In the spinal cord under normal circumstances, the AMPA receptor subunit GluR1 is expressed at high levels by motor neurons and surrounding interneurons during this critical developmental period, although the role it plays in circuit formation and locomotor behavior is unknown. Here, we show that GluR1 promotes dendrite growth in a non-cell-autonomous manner in vitro and in vivo. The mal-development of motor neuron dendrites is associated with changes in the pattern of interneuronal connectivity within the segmental spinal cord and defects in strength and endurance. Transgenic expression of GluR1 in adult motor neurons leads to dendrite remodeling and supernormal locomotor function. GluR1 expression by neurons within the segmental spinal cord plays an essential role in formation of the neural network that underlies normal motor behavior. PMID:18829953

  15. Extraction of motion strength and motor activity signals from video recordings of neonatal seizures.

    PubMed

    Karayiannis, N B; Srinivasan, S; Bhattacharya, R; Wise, M S; Frost, J D; Mizrahi, E M

    2001-09-01

    This paper presents two methods developed to extract quantitative information from video recordings of neonatal seizures in the form of temporal motion strength and motor activity signals. Motion strength signals are extracted by measuring the area of the body parts that move during the seizure and the relative speed of motion using a combination of spatiotemporal subband decomposition of video, nonlinear filtering, and segmentation. Motor activity signals are extracted by tracking selected anatomical sites during the seizure using a modified version of a feature-tracking procedure developed for video, known as the Kanade-Lucas-Tomasi (KLT) algorithm. The experiments indicate that the temporal signals produced by the proposed methods provide the basis for differentiating myoclonic from focal clonic seizures and distinguishing these types of neonatal seizures from normal infant behaviors. PMID:11585212

  16. Done that: short-term repetition related modulations of motor cortex activity as a stable signature for overnight motor memory consolidation.

    PubMed

    Gabitov, Ella; Manor, David; Karni, Avi

    2014-12-01

    An almost universally accepted tacit expectation is that learning and memory consolidation processes must be reflected in the average brain activity in brain areas relevant to task performance. Motor cortex (M1) plasticity has been implicated in motor skill acquisition and its consolidation. Nevertheless, no consistent pattern of changes in the average signal, related to motor learning or motor memory consolidation following a single session of training, has emerged from imaging studies. Here we show that the pattern and magnitude of short-term brain activity modulations in response to task repetition, in M1, may provide a robust signature for effective motor memory consolidation processes. We studied participants during the paced performance of a finger-to-thumb opposition sequence (FOS), intensively trained a day earlier, and a similarly constructed untrained FOS. In addition to within-session "on-line" gains, most participants expressed delayed, consolidation-phase gains in the performance of the trained FOS. The execution of the trained FOS induced repetition enhancements in the contralateral M1 and bilaterally in the medial-temporal lobes, offsetting novelty-related repetition suppression effects. Moreover, the M1 modulations were positively correlated with the magnitude of each participant's overnight delayed gains but not with absolute performance levels. Our results suggest that short-term enhancements of brain signals upon task repetition reflect the effectiveness of overnight motor memory consolidation. We propose that procedural memory consolidation processes may affect the excitation-inhibition balance within cortical representations of the trained movements; this new balance is better reflected in repetition effects than in the average level of evoked neural activity. PMID:24893741

  17. Dynamics of brain activity in motor and frontal cortical areas during music listening: a magnetoencephalographic study.

    PubMed

    Popescu, Mihai; Otsuka, Asuka; Ioannides, Andreas A

    2004-04-01

    There are formidable problems in studying how 'real' music engages the brain over wide ranges of temporal scales extending from milliseconds to a lifetime. In this work, we recorded the magnetoencephalographic signal while subjects listened to music as it unfolded over long periods of time (seconds), and we developed and applied methods to correlate the time course of the regional brain activations with the dynamic aspects of the musical sound. We showed that frontal areas generally respond with slow time constants to the music, reflecting their more integrative mode; motor-related areas showed transient-mode responses to fine temporal scale structures of the sound. The study combined novel analysis techniques designed to capture and quantify fine temporal sequencing from the authentic musical piece (characterized by a clearly defined rhythm and melodic structure) with the extraction of relevant features from the dynamics of the regional brain activations. The results demonstrated that activity in motor-related structures, specifically in lateral premotor areas, supplementary motor areas, and somatomotor areas, correlated with measures of rhythmicity derived from the music. These correlations showed distinct laterality depending on how the musical performance deviated from the strict tempo of the music score, that is, depending on the musical expression. PMID:15050586

  18. Neural control of computer cursor velocity by decoding motor cortical spiking activity in humans with tetraplegia

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Phil; Simeral, John D.; Hochberg, Leigh R.; Donoghue, John P.; Black, Michael J.

    2008-12-01

    Computer-mediated connections between human motor cortical neurons and assistive devices promise to improve or restore lost function in people with paralysis. Recently, a pilot clinical study of an intracortical neural interface system demonstrated that a tetraplegic human was able to obtain continuous two-dimensional control of a computer cursor using neural activity recorded from his motor cortex. This control, however, was not sufficiently accurate for reliable use in many common computer control tasks. Here, we studied several central design choices for such a system including the kinematic representation for cursor movement, the decoding method that translates neuronal ensemble spiking activity into a control signal and the cursor control task used during training for optimizing the parameters of the decoding method. In two tetraplegic participants, we found that controlling a cursor's velocity resulted in more accurate closed-loop control than controlling its position directly and that cursor velocity control was achieved more rapidly than position control. Control quality was further improved over conventional linear filters by using a probabilistic method, the Kalman filter, to decode human motor cortical activity. Performance assessment based on standard metrics used for the evaluation of a wide range of pointing devices demonstrated significantly improved cursor control with velocity rather than position decoding. Disclosure. JPD is the Chief Scientific Officer and a director of Cyberkinetics Neurotechnology Systems (CYKN); he holds stock and receives compensation. JDS has been a consultant for CYKN. LRH receives clinical trial support from CYKN.

  19. [Implantable cardioverter/defibrillator: long-term stability of the defibrillation threshold with a unipolar electrode configuration (active-can")].

    PubMed

    Knuefermann, P; Wolpert, C; Spehl, S; Korte, T; Manz, M; Lüderitz, B; Jung, W

    2000-09-01

    The majority of cardioverter/defibrillator (ICD) implantations are currently performed with a non-thoracotomy approach. From November 1993 to January 1995, 46 patients underwent implantation of a PCD 7219C with an "active-can" lead configuration at our institution. While the chronic stability of the defibrillation threshold (DFT) for an epicardial lead system is well established, the results are still inconsistent for non-thoracotomy lead systems. Accordingly, the aim of the present study was to compare the acute and chronic defibrillation thresholds of the ICDs implanted with an "active-can" lead system in order to assess the chronic stability of these systems. The defibrillation energy requirements were measured at implant, prior to hospital discharge, three, six and twelve months after implantation of the defibrillator. The patient group consisted of 8 females and 38 males with a mean age of 57.2 years. The mean left ventricular ejection fraction was 43.8%. The most frequent underlying heart disease was coronary artery disease in 31 of 46 patients. Eight patients had idiopathic dilated cardiomyopathy. In 39 of 46 patients, the defibrillation threshold could be successfully determined at all 4 time points after implantation. The mean defibrillation energy requirement at the time of implantation was 9.2 +/- 5.9 Joules (J). The subsequent mean energy requirements were 7.6 +/- 4.8 J at pre-hospital discharge, 8.6 +/- 5.7 J at the 3 month, 8.1 +/- 6.0 J at the 6 month and 8.6 +/- 5.8 J at the 12 month follow-up visits. The mean defibrillation threshold was lowest at the time of prehospital discharge, significantly lower than at the time of initial implantation (p = 0.021). However, at all later time points up to one year, there was no significant difference in the DFT as compared with the time of initial implantation. Comparing the DFT at the time of implantation and the DFT at all other time points, there were no significant differences (9.23 vs. 8.56 J, p = 0

  20. Coordination of Fictive Motor Activity in the Larval Zebrafish Is Generated by Non-Segmental Mechanisms

    PubMed Central

    Wiggin, Timothy D.; Peck, Jack H.; Masino, Mark A.

    2014-01-01

    The cellular and network basis for most vertebrate locomotor central pattern generators (CPGs) is incompletely characterized, but organizational models based on known CPG architectures have been proposed. Segmental models propose that each spinal segment contains a circuit that controls local coordination and sends longer projections to coordinate activity between segments. Unsegmented/continuous models propose that patterned motor output is driven by gradients of neurons and synapses that do not have segmental boundaries. We tested these ideas in the larval zebrafish, an animal that swims in discrete episodes, each of which is composed of coordinated motor bursts that progress rostrocaudally and alternate from side to side. We perturbed the spinal cord using spinal transections or strychnine application and measured the effect on fictive motor output. Spinal transections eliminated episode structure, and reduced both rostrocaudal and side-to-side coordination. Preparations with fewer intact segments were more severely affected, and preparations consisting of midbody and caudal segments were more severely affected than those consisting of rostral segments. In reduced preparations with the same number of intact spinal segments, side-to-side coordination was more severely disrupted than rostrocaudal coordination. Reducing glycine receptor signaling with strychnine reversibly disrupted both rostrocaudal and side-to-side coordination in spinalized larvae without disrupting episodic structure. Both spinal transection and strychnine decreased the stability of the motor rhythm, but this effect was not causal in reducing coordination. These results are inconsistent with a segmented model of the spinal cord and are better explained by a continuous model in which motor neuron coordination is controlled by segment-spanning microcircuits. PMID:25275377

  1. The influence of social evaluation on cerebral cortical activity and motor performance: a study of "Real-Life" competition.

    PubMed

    Hatfield, Bradley D; Costanzo, Michelle E; Goodman, Ronald N; Lo, Li-Chuan; Oh, Hyuk; Rietschel, Jeremy C; Saffer, Mark; Bradberry, Trent; Contreras-Vidal, Jose; Haufler, Amy

    2013-11-01

    Motor performance in a social evaluative environment was examined in participants (N = 19) who completed a pistol shooting task under both performance-alone (PA) and competitive (C) conditions. Electroencephalographic (EEG), autonomic, and psychoendocrine activity were recorded in addition to kinematic measures of the aiming behavior. State anxiety, heart rate, and cortisol were modestly elevated during C and accompanied by relative desynchrony of high-alpha power, increased cortico-cortical communication between motor and non-motor regions, and degradation of the fluency of aiming trajectory, but maintenance of performance outcome (i.e., score). The findings reveal that performance in a complex social-evaluative environment characterized by competition results in elevated cortical activity beyond that essentially required for motor performance that translated as less efficient motor behavior. PMID:23954302

  2. [The blood glucose content in newborn rats depending on level and pattern of spontaneous motor activity].

    PubMed

    Kuznetsov, S V; Selina, E N; Kuznetsova, N N

    2011-01-01

    Earlier we have shown that administration to newborn rats of the pentose phosphate cycle inhibitor hydroquinone leads to a change in intensity and pattern of spontaneous periodic motor activity (SPMA) characteristic of early stages of development. The most typical was the disappearance of the rest period from the near-minute cycle "activity--rest" and the appearance of uninterrupted motor activity. In several cases, especially after 10 days of development, there was noted an enhancement in the SMPA pattern of the motor activity complexes following in the decasecond rhythm. In this study, on the 3-10-day old rats maintained under conditions of free behavior there was studied the blood glucose content in the animals at various periods of the activity-rest cycle. Apart from the SPMA phase, its composition (pattern) characterizing the maturity level and functional state of spinal motor centers was taken into account. In the 3, 7 and 10-day old rats at the rest period, the glucose concentration was established to differ depending on the motor activity pattern. In the case of the decasecond periodicity, it amounts to 5.7 +/- 0.2, 6.3 +/- +/- 0.3, and 7.7 +/- 0.3 mmol/l, while at the minute one--6.1 +/- 0.4, 7.8 +/- 0.3, and 7.8 +/- 0.1 mmol/l. At the moment of bursts of motor excitation, the glucose concentration falls to 5.2 +/- 0.1, 6.1 +/- 0.4, and 7.1 +/- +/- 0.3 mm at the decasecond and to 5.4 +/- 0.5, 6.7 +/- 0.2, and 7.6 +/- 0.3 mmol/l at the near-minute rhythm (for the 3, 7 and 10-day old animals, respectively). The results obtained on the 5-day rat pups differ qualitatively from those observed in other age groups. Thus, the glucose concentration at the rest period amounts to 6.8 +/- 0.2 at the decasecond and to 6.7 +/- 0.4 mmol/l at the nearminute periodicity. At the period of motor excitation accompanied by the presence of the decasecond activity rhythm, the glucose concentration falls to the level of 6.0 +/- 0.2 mmol/l by differing statistically significantly

  3. Proton and Electron Threshold Energy Measurements for Extravehicular Activity Space Suits. Chapter 2

    NASA Technical Reports Server (NTRS)

    Moyers, M. F.; Nelson, G. D.; Saganti, P. B.

    2003-01-01

    Construction of ISS will require more than 1000 hours of EVA. Outside of ISS during EVA, astronauts and cosmonauts are likely to be exposed to a large fluence of electrons and protons. Development of radiation protection guidelines requires the determination of the minimum energy of electrons and protons that penetrate the suits at various locations. Measurements of the water-equivalent thickness of both US. and Russian EVA suits were obtained by performing CT scans. Specific regions of interest of the suits were further evaluated using a differential range shift technique. This technique involved measuring thickness ionization curves for 6-MeV electron and 155-MeV proton beams with ionization chambers using a constant source-to-detector distance. The thicknesses were obtained by stacking polystyrene slabs immediately upstream of the detector. The thicknesses of the 50% ionizations relative to the maximum ionizations were determined. The detectors were then placed within the suit and the stack thickness adjusted until the 50% ionization was reestablished. The difference in thickness between the 50% thicknesses was then used with standard range-energy tables to determine the threshold energy for penetration. This report provides a detailed description of the experimental arrangement and results.

  4. Body stability and muscle and motor cortex activity during walking with wide stance.

    PubMed

    Farrell, Brad J; Bulgakova, Margarita A; Beloozerova, Irina N; Sirota, Mikhail G; Prilutsky, Boris I

    2014-08-01

    Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity of limb muscles, and activity of motor cortex neurons [primarily pyramidal tract neurons (PTNs)] in the cat during unconstrained walking and walking with a wide base of support (wide-stance walking). By recording three-dimensional full-body kinematics we found for the first time that during unconstrained walking the cat is dynamically unstable in the forward direction during stride phases when only two diagonal limbs support the body. In contrast to standing, an increased lateral between-paw distance during walking dramatically decreased the cat's body dynamic stability in double-support phases and prompted the cat to spend more time in three-legged support phases. Muscles contributing to abduction-adduction actions had higher activity during stance, while flexor muscles had higher activity during swing of wide-stance walking. The overwhelming majority of neurons in layer V of the motor cortex, 82% and 83% in the forelimb and hindlimb representation areas, respectively, were active differently during wide-stance walking compared with unconstrained condition, most often by having a different depth of stride-related frequency modulation along with a different mean discharge rate and/or preferred activity phase. Upon transition from unconstrained to wide-stance walking, proximal limb-related neuronal groups subtly but statistically significantly shifted their activity toward the swing phase, the stride phase where most of body instability occurs during this task. The data suggest that the motor cortex participates in maintenance of body dynamic stability during locomotion. PMID:24790167

  5. Body stability and muscle and motor cortex activity during walking with wide stance

    PubMed Central

    Farrell, Brad J.; Bulgakova, Margarita A.; Beloozerova, Irina N.; Sirota, Mikhail G.

    2014-01-01

    Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity of limb muscles, and activity of motor cortex neurons [primarily pyramidal tract neurons (PTNs)] in the cat during unconstrained walking and walking with a wide base of support (wide-stance walking). By recording three-dimensional full-body kinematics we found for the first time that during unconstrained walking the cat is dynamically unstable in the forward direction during stride phases when only two diagonal limbs support the body. In contrast to standing, an increased lateral between-paw distance during walking dramatically decreased the cat's body dynamic stability in double-support phases and prompted the cat to spend more time in three-legged support phases. Muscles contributing to abduction-adduction actions had higher activity during stance, while flexor muscles had higher activity during swing of wide-stance walking. The overwhelming majority of neurons in layer V of the motor cortex, 82% and 83% in the forelimb and hindlimb representation areas, respectively, were active differently during wide-stance walking compared with unconstrained condition, most often by having a different depth of stride-related frequency modulation along with a different mean discharge rate and/or preferred activity phase. Upon transition from unconstrained to wide-stance walking, proximal limb-related neuronal groups subtly but statistically significantly shifted their activity toward the swing phase, the stride phase where most of body instability occurs during this task. The data suggest that the motor cortex participates in maintenance of body dynamic stability during locomotion. PMID:24790167

  6. Prognostic value of cortically induced motor evoked activity by TMS in chronic stroke: Caveats from a revealing single clinical case

    PubMed Central

    2012-01-01

    Background We report the case of a chronic stroke patient (62 months after injury) showing total absence of motor activity evoked by transcranial magnetic stimulation (TMS) of spared regions of the left motor cortex, but near-to-complete recovery of motor abilities in the affected hand. Case presentation Multimodal investigations included detailed TMS based motor mapping, motor evoked potentials (MEP), and Cortical Silent period (CSP) as well as functional magnetic resonance imaging (fMRI) of motor activity, MRI based lesion analysis and Diffusion Tensor Imaging (DTI) Tractography of corticospinal tract (CST). Anatomical analysis revealed a left hemisphere subinsular lesion interrupting the descending left CST at the level of the internal capsule. The absence of MEPs after intense TMS pulses to the ipsilesional M1, and the reversible suppression of ongoing electromyographic (EMG) activity (indexed by CSP) demonstrate a weak modulation of subcortical systems by the ipsilesional left frontal cortex, but an inability to induce efficient descending volleys from those cortical locations to right hand and forearm muscles. Functional MRI recordings under grasping and finger tapping patterns involving the affected hand showed slight signs of subcortical recruitment, as compared to the unaffected hand and hemisphere, as well as the expected cortical activations. Conclusions The potential sources of motor voluntary activity for the affected hand in absence of MEPs are discussed. We conclude that multimodal analysis may contribute to a more accurate prognosis of stroke patients. PMID:22682434

  7. Normal activation of the supplementary motor area in patients with Parkinson's disease undergoing long-term treatment with levodopa.

    PubMed Central

    Rascol, O; Sabatini, U; Chollet, F; Fabre, N; Senard, J M; Montastruc, J L; Celsis, P; Marc-Vergnes, J P; Rascol, A

    1994-01-01

    Regional cerebral blood flow (rCBF) changes in cortical motor areas were measured during a movement of the dominant right hand in 15 patients with Parkinson's disease deprived of their usual levodopa treatment, in 11 patients with Parkinson's disease undergoing long-term treatment with levodopa, and in 15 normal volunteers. The supplementary motor areas were significantly activated in the normal subjects and in the patients receiving levodopa but not in the patients deprived of levodopa. The contralateral primary sensory motor area was significantly activated in all three groups. The ipsilateral primary sensory motor cortex was not activated in the normal subjects and the non-treated patients but was in the patients treated with levodopa. It is concluded that the supplementary motor area hypoactivation which is observed in akinetic non-treated patients with Parkinson's disease is not present in patients undergoing long-term treatment with levodopa. This result suggests that (a) levodopa improves the functional activity of supplementary motor areas in Parkinson's disease and (b) there is no pharmacological tolerance to this effect. The ipsilateral primary motor cortex activation observed in the patients treated with levodopa could be related to levodopa-induced abnormal involuntary movements. PMID:8201325

  8. D-Aspartate Modulates Nociceptive-Specific Neuron Activity and Pain Threshold in Inflammatory and Neuropathic Pain Condition in Mice

    PubMed Central

    Boccella, Serena; Vacca, Valentina; Errico, Francesco; Marinelli, Sara; Squillace, Marta; Di Maio, Anna; Vitucci, Daniela; Palazzo, Enza; De Novellis, Vito; Maione, Sabatino; Pavone, Flaminia; Usiello, Alessandro

    2015-01-01

    D-Aspartate (D-Asp) is a free D-amino acid found in the mammalian brain with a temporal-dependent concentration based on the postnatal expression of its metabolizing enzyme D-aspartate oxidase (DDO). D-Asp acts as an agonist on NMDA receptors (NMDARs). Accordingly, high levels of D-Asp in knockout mice for Ddo gene (Ddo−/−) or in mice treated with D-Asp increase NMDAR-dependent processes. We have here evaluated in Ddo−/− mice the effect of high levels of free D-Asp on the long-term plastic changes along the nociceptive pathway occurring in chronic and acute pain condition. We found that Ddo−/− mice show an increased evoked activity of the nociceptive specific (NS) neurons of the dorsal horn of the spinal cord (L4–L6) and a significant decrease of mechanical and thermal thresholds, as compared to control mice. Moreover, Ddo gene deletion exacerbated the nocifensive responses in the formalin test and slightly reduced pain thresholds in neuropathic mice up to 7 days after chronic constriction injury. These findings suggest that the NMDAR agonist, D-Asp, may play a role in the regulation of NS neuron electrophysiological activity and behavioral responses in physiological and pathological pain conditions. PMID:25629055

  9. Threshold Levels of Gfi1 Maintain E2A Activity for B Cell Commitment via Repression of Id1

    PubMed Central

    Fraszczak, Jennifer; Helness, Anne; Chen, Riyan; Vadnais, Charles; Robert, François; Khandanpour, Cyrus; Möröy, Tarik

    2016-01-01

    A regulatory circuit that controls myeloid versus B lymphoid cell fate in hematopoietic progenitors has been proposed, in which a network of the transcription factors Egr1/2, Nab, Gfi1 and PU.1 forms the core element. Here we show that a direct link between Gfi1, the transcription factor E2A and its inhibitor Id1 is a critical element of this regulatory circuit. Our data suggest that a certain threshold of Gfi1 is required to gauge E2A activity by adjusting levels of Id1 in multipotent progenitors, which are the first bipotential myeloid/lymphoid-restricted progeny of hematopoietic stem cells. If Gfi1 levels are high, Id1 is repressed enabling E2A to activate a specific set of B lineage genes by binding to regulatory elements for example the IL7 receptor gene. If Gfi1 levels fall below a threshold, Id1 expression increases and renders E2A unable to function, which prevents hematopoietic progenitors from engaging along the B lymphoid lineage. PMID:27467586

  10. RELATIONSHIP BETWEEN SERUM CHOLINESTERASE ACTIVITY AND THE CHANGE IN BODY TEMPERATURE AND MOTOR ACTIVITY IN THE RAT: A DOSE RESPONSE STUDY OF DIISOPROPYL FLUOROPHATE (DFP)

    EPA Science Inventory

    Risk assessment of the neurotoxicology of organophosphate (OP) pesticides calls for a thorough understanding of the relationship between tissue cholinesterase (ChE) activity and changes in behavioral and autonomic responses to OP treatment. To address this issue, motor activity, ...

  11. Subthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson's disease.

    PubMed

    Weiss, Daniel; Klotz, Rosa; Govindan, Rathinaswamy B; Scholten, Marlieke; Naros, Georgios; Ramos-Murguialday, Ander; Bunjes, Friedemann; Meisner, Christoph; Plewnia, Christian; Krüger, Rejko; Gharabaghi, Alireza

    2015-03-01

    Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson's disease. Here, we set out to address the motor network activity and synchronization in Parkinson's disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson's disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with 'stimulation on' compared to 'stimulation off' on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With 'stimulation on', interhemispheric cortico

  12. Facial warming increases the threshold for shivering.

    PubMed

    Iaizzo, P A; Jeon, Y M; Sigg, D C

    1999-10-01

    A decrease of 1-2 degrees C core temperature provides protection against cerebral ischemia. However, shivering usually prevents reduction in core temperature in unanesthetized patients. Therefore, it was tested whether facial and airway heating increases the shivering threshold and enables core cooling in unanesthetized patients. Nine trials were performed on seven healthy male volunteers. Each subject was positioned supine on a circulating-water mattress (8-15 degrees C) with a convective-air coverlet (15-18 degrees C) extending from the neck to the feet. A dynamic study protocol governed by individualized physiological responses was used. Focal facial (and airway) warming was employed to suppress involuntary motor activity (muscle tensing, shivering) and, thereby, enabling noninvasive cooling to lower the core temperature. The following parameters were monitored: 1) heart rate, 2) blood pressure, 3) core temperature (tympanic, axilla, and rectal), 4) cutaneous temperatures, and 5) a subjective shiver index (scale 1-10). In three, electromyograms and infrared thermographs were also obtained. Upon cooling without facial and airway warming, involuntary motor activity increased until it was widespread. This vigorous motor activity prevented any significant lowering of core temperature or caused it to slightly increase. Subsequently, in all subjects, within seconds after the application of facial focal warming, motor activity was suppressed almost completely, and within minutes core temperatures significantly decreased. Preliminary studies described here indicate that focal facial warming applied during active whole body cooling to initiate mild hypothermia might minimize the need to pharmacologically suppress involuntary motor activity. Such a procedure might be useful for initiating as soon as possible (such as during emergency transport), cerebral mild hypothermia in order to maximize protection and thus improve outcome in neurologically injured patients (head

  13. Assessing Upper Extremity Motor Function in Practice of Virtual Activities of Daily Living

    PubMed Central

    Adams, Richard J.; Lichter, Matthew D.; Krepkovich, Eileen T.; Ellington, Allison; White, Marga; Diamond, Paul T.

    2015-01-01

    A study was conducted to investigate the criterion validity of measures of upper extremity (UE) motor function derived during practice of virtual activities of daily living (ADLs). Fourteen hemiparetic stroke patients employed a Virtual Occupational Therapy Assistant (VOTA), consisting of a high-fidelity virtual world and a Kinect™ sensor, in four sessions of approximately one hour in duration. An Unscented Kalman Filter-based human motion tracking algorithm estimated UE joint kinematics in real-time during performance of virtual ADL activities, enabling both animation of the user’s avatar and automated generation of metrics related to speed and smoothness of motion. These metrics, aggregated over discrete sub-task elements during performance of virtual ADLs, were compared to scores from an established assessment of UE motor performance, the Wolf Motor Function Test (WMFT). Spearman’s rank correlation analysis indicates a moderate correlation between VOTA-derived metrics and the time-based WMFT assessments, supporting the criterion validity of VOTA measures as a means of tracking patient progress during an UE rehabilitation program that includes practice of virtual ADLs. PMID:25265612

  14. Abnormal Motor Activity and Thermoregulation in a Schizophrenia Rat Model for Translational Science

    PubMed Central

    2015-01-01

    Background Schizophrenia is accompanied by altered motor activity and abnormal thermoregulation; therefore, the presence of these symptoms can enhance the face validity of a schizophrenia animal model. The goal was to characterize these parameters in freely moving condition of a new substrain of rats showing several schizophrenia-related alterations. Methods Male Wistar rats were used: the new substrain housed individually (for four weeks) and treated subchronically with ketamine, and naive animals without any manipulations. Adult animals were implanted with E-Mitter transponders intraabdominally to record body temperature and locomotor activity continuously. The circadian rhythm of these parameters and the acute effects of changes in light conditions were analyzed under undisturbed circumstances, and the effects of different interventions (handling, bed changing or intraperitoneal vehicle injection) were also determined. Results Decreased motor activity with fragmented pattern was observed in the new substrain. However, these animals had higher body temperature during the active phase, and they showed wider range of its alterations, too. The changes in light conditions and different interventions produced blunted hyperactivity and altered body temperature responses in the new substrain. Poincaré plot analysis of body temperature revealed enhanced short- and long-term variabilities during the active phase compared to the inactive phase in both groups. Furthermore, the new substrain showed increased short- and long-term variabilities with lower degree of asymmetry suggesting autonomic dysregulation. Conclusions In summary, the new substrain with schizophrenia-related phenomena showed disturbed motor activity and thermoregulation suggesting that these objectively determined parameters can be biomarkers in translational research. PMID:26629908

  15. Laterality of brain activity during motor imagery is modulated by the provision of source level neurofeedback.

    PubMed

    Boe, Shaun; Gionfriddo, Alicia; Kraeutner, Sarah; Tremblay, Antoine; Little, Graham; Bardouille, Timothy

    2014-11-01

    Motor imagery (MI) may be effective as an adjunct to physical practice for motor skill acquisition. For example, MI is emerging as an effective treatment in stroke neurorehabilitation. As in physical practice, the repetitive activation of neural pathways during MI can drive short- and long-term brain changes that underlie functional recovery. However, the lack of feedback about MI performance may be a factor limiting its effectiveness. The provision of feedback about MI-related brain activity may overcome this limitation by providing the opportunity for individuals to monitor their own performance of this endogenous process. We completed a controlled study to isolate neurofeedback as the factor driving changes in MI-related brain activity across repeated sessions. Eighteen healthy participants took part in 3 sessions comprised of both actual and imagined performance of a button press task. During MI, participants in the neurofeedback group received source level feedback based on activity from the left and right sensorimotor cortex obtained using magnetoencephalography. Participants in the control group received no neurofeedback. MI-related brain activity increased in the sensorimotor cortex contralateral to the imagined movement across sessions in the neurofeedback group, but not in controls. Task performance improved across sessions but did not differ between groups. Our results indicate that the provision of neurofeedback during MI allows healthy individuals to modulate regional brain activity. This finding has the potential to improve the effectiveness of MI as a tool in neurorehabilitation. PMID:24999037

  16. Biomechanics of the vibrissa motor plant in rat: rhythmic whisking consists of triphasic neuromuscular activity.

    PubMed

    Hill, Dan N; Bermejo, Roberto; Zeigler, H Philip; Kleinfeld, David

    2008-03-26

    The biomechanics of a motor plant constrain the behavioral strategies that an animal has available to extract information from its environment. We used the rat vibrissa system as a model for active sensing and determined the pattern of muscle activity that drives rhythmic exploratory whisking. Our approach made use of electromyography to measure the activation of all relevant muscles in both head-fixed and unrestrained rats and two-dimensional imaging to monitor the position of the vibrissae in head-fixed rats. Our essential finding is that the periodic motion of the vibrissae and mystacial pad during whisking results from three phases of muscle activity. First, the vibrissae are thrust forward as the rostral extrinsic muscle, musculus (m.) nasalis, contracts to pull the pad and initiate protraction. Second, late in protraction, the intrinsic muscles pivot the vibrissae farther forward. Third, retraction involves the cessation of m. nasalis and intrinsic muscle activity and the contraction of the caudal extrinsic muscles m. nasolabialis and m. maxillolabialis to pull the pad and the vibrissae backward. We developed a biomechanical model of the whisking motor plant that incorporates the measured muscular mechanics along with movement vectors observed from direct muscle stimulation in anesthetized rats. The results of simulations of the model quantify how the combination of extrinsic and intrinsic muscle activity leads to an enhanced range of vibrissa motion than would be available from the intrinsic muscles alone. PMID:18367610

  17. Understanding Threshold Effects of Organized Activity Involvement in Adolescents: Sex and Family Income as Moderators

    ERIC Educational Resources Information Center

    Randall, Edin T.; Bohnert, Amy M.

    2012-01-01

    The current study examined the curvilinear links between involvement in organized activities (OA) and sport activities specifically and various indicators of psychological and social development. Participants included 150 9th and 10th graders (57% females) from an urban, selective-enrollment high school. Eligibility for admission is based on city…

  18. Calorigenic effect of adrenaline in rats under conditions of restricted motor activity

    NASA Technical Reports Server (NTRS)

    Tomaszewska, L.; Kaciuba-Uscilko, H.; Kozlowski, S.

    1980-01-01

    In previous studies, it was demonstrated that long term restricted motor activity in rats induces a decrease in body weight, an increase in release of adrenaline, and a decrease in the release of noradrenaline with the urine, as well as a reduction in activity of the thymus gland and level of thyroxin in the blood. At the same time, a decrease was found in the internal body temperature that was accompanied by an increase in the rate of metabolism in the state of rest. An investigation is presented which attempts to clarify whether the calorigenic effect of adrenaline under conditions of increased metabolism in the period of immobility is exposed to changes.

  19. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures

    PubMed Central

    Sohn, M. Hongchul; Ting, Lena H.

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual

  20. Brain Activity During a Motor Learning Task: An fMRI and Skin Conductance Study

    PubMed Central

    MacIntosh, Bradley J.; Mraz, Richard; McIlroy, William E.; Graham, Simon J.

    2016-01-01

    Measuring electrodermal activity (EDA) during fMRI is an effective means of studying the influence of task-related arousal, inferred from autonomic nervous system activity, on brain activation patterns. The goals of this study were: (1) to measure reliable EDA from healthy individuals during fMRI involving an effortful unilateral motor task, (2) to explore how EDA recordings can be used to augment fMRI data analysis. In addition to conventional hemodynamic modeling, skin conductance time series data were used as model waveforms to generate activation images from fMRI data. Activations from the EDA model produced significantly different brain regions from those obtained with a standard hemodynamic model, primarily in the insula and cingulate cortices. Onsets of the EDA changes were synchronous with the hemodynamic model, but EDA data showed additional transient features, such as a decrease in amplitude with time, and helped to provide behavioral evidence suggesting task difficulty decreased with movement repetition. Univariate statistics also confirmed that several brain regions showed early versus late session effects. Partial least squares (PLS) multivariate analysis of EDA and fMRI data provided complimentary, additional insight on how the motor network varied over the course of a single fMRI session. Brain regions identified in this manner included the insula, cingulate gyrus, pre- and postcentral gyri, putamen and parietal cortices. These results suggest that recording EDA during motor fMRI experiments provides complementary information that can be used to improve the fMRI analysis, particularly when behavioral or task effects are difficult to model a priori. PMID:17318835

  1. Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo.

    PubMed

    Ward, Patricia J; Jones, Laura N; Mulligan, Amanda; Goolsby, William; Wilhelm, Jennifer C; English, Arthur W

    2016-01-01

    Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation) that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2), we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2) to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555) was greater in mice that received optical treatment. Thus, the acute (1 hour), one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-). We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons. PMID:27152611

  2. Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo

    PubMed Central

    Ward, Patricia J.; Jones, Laura N.; Mulligan, Amanda; Goolsby, William; Wilhelm, Jennifer C.; English, Arthur W.

    2016-01-01

    Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation) that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2), we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2) to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555) was greater in mice that received optical treatment. Thus, the acute (1 hour), one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-). We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons. PMID:27152611

  3. Molecular motors

    NASA Astrophysics Data System (ADS)

    Allemand, Jean François Desbiolles, Pierre

    2015-10-01

    How do we move? More precisely, what are the molecular mechanisms that can explain that our muscles, made of very small components can move at a osopic scale? To answer these questions we must introduce molecular motors. Those motors are proteins, or small protein assemblies that, in our cells, transform chemical energy into mechanical work. Then, like we could do for a oscopic motor, used in a car or in a fan, we are going to study the basic behavior of these molecular machines, present what are their energy sources, calculate their power, their yield. If molecular motors are crucial for our oscopic movements, we are going to see that they are also essential to cellular transport and that considering the activity of some enzymes as molecular motors bring some interesting new insights on their activity.

  4. The Relationship of Neuronal Activity within the Sensori-Motor Region of the Subthalamic Nucleus to Speech

    ERIC Educational Resources Information Center

    Watson, Peter; Montgomery, Erwin B., Jr.

    2006-01-01

    Microelectrode recordings of human sensori-motor subthalamic neuronal activity during spoken sentence and syllable-repetition tasks provided an opportunity to evaluate the relationship between changes in neuronal activities and specific aspects of these vocal behaviors. Observed patterns of neuronal activity included a build up of activity in…

  5. Prediction of motor outcomes and activities of daily living function using diffusion tensor tractography in acute hemiparetic stroke patients

    PubMed Central

    Imura, Takeshi; Nagasawa, Yuki; Inagawa, Tetsuji; Imada, Naoki; Izumi, Hiroaki; Emoto, Katsuya; Tani, Itaru; Yamasaki, Hiroyuki; Ota, Yuichiro; Oki, Shuichi; Maeda, Tadanori; Araki, Osamu

    2015-01-01

    [Purpose] The efficacy of diffusion tensor imaging in the prediction of motor outcomes and activities of daily living function remains unclear. We evaluated the most appropriate diffusion tensor parameters and methodology to determine whether the region of interest- or tractography-based method was more useful for predicting motor outcomes and activities of daily living function in stroke patients. [Subjects and Methods] Diffusion tensor imaging data within 10 days after stroke onset were collected and analyzed for 25 patients. The corticospinal tract was analyzed. Fractional anisotropy, number of fibers, and apparent diffusion coefficient were used as diffusion tensor parameters. Motor outcomes and activities of daily living function were evaluated on the same day as diffusion tensor imaging and at 1 month post-onset. [Results] The fractional anisotropy value of the affected corticospinal tract significantly correlated with the motor outcome and activities of daily living function within 10 days post-onset and at 1 month post-onset. Tthere were no significant correlations between other diffusion tensor parameters and motor outcomes or activities of daily living function. [Conclusion] The fractional anisotropy value of the affected corticospinal tract obtained using the tractography-based method was useful for predicting motor outcomes and activities of daily living function in stroke patients. PMID:26157225

  6. Neostriatal modulation of motor cortex excitability.

    PubMed

    Ryan, L J; Sanders, D J

    1994-07-18

    The influence of the basal ganglia motor loop on motor cortex function was examined by pharmacologically altering neostriatal activity while monitoring the electrical stimulation thresholds for eliciting movements of the ipsilateral and contralateral motor cortex in ketamine anesthetized rats. Repeated unilateral intraneostriatal infusions (1-3) of the glutamate agonist, kainic acid (0.1 microliter, 75 ng), or glutamate (0.3 microliter, 1.65 micrograms) reliably increased ipsilateral but not contralateral cortical thresholds. Single infusions of kainic acid (0.3 microliter, 150 or 225 ng) elevated ipsilateral cortical thresholds for 30-45 min; with glutamate (0.3 microliter, 1.65 micrograms), the change lasted less than 10 min. Antidromically identified striatonigral projection neurons (n = 8) located approximately 500 microM from the infusion cannula, showed either increased firing (n = 4) for less than 10 min following glutamate infusion or no change from their non-firing state (n = 4). Non-antidromically activated neurons (n = 3) were all excited by the infusion, although an interval of inhibition preceded or followed the excitation in two cases. Infusions (0.3 microliter) of inhibitory agents (GABA, 31 and 310 ng; muscimol 34.2 ng; and DNQX 34.2 ng) did not alter cortical threshold, nor did saline vehicle. Lesion of the ventrolateral but not ventromedial thalamic nucleus prevented the modulation of cortical thresholds following intraneostriatal infusion of 225 ng kainic acid. Thus the neostriatal alteration of cortical thresholds indicates a modulation of cortical excitability via thalamic projections and not the outcome of competing descending cortical and neonstriatal influences converging on motorneurons. These results suggest that tonic feedforward modulation of the motor cortex and the pyramidal tract by the basal ganglia can be inhibitory. PMID:7922571

  7. Metabolic Thresholds and Validated Accelerometer Cutoff Points for the Actigraph GT1M in Young Children Based on Measurements of Locomotion and Play Activities

    ERIC Educational Resources Information Center

    Jimmy, Gerda; Dossegger, Alain; Seiler, Roland; Mader, Urs

    2012-01-01

    The purpose of the current study was to determine metabolic thresholds and subsequent activity intensity cutoff points for the ActiGraph GT1M with various epochs spanning from 5 to 60 sec in young children. Twenty-two children, aged 4 to 9 years, performed 10 different activities including locomotion and play activities. Energy expenditure was…

  8. Differential Neural Processing during Motor Imagery of Daily Activities in Chronic Low Back Pain Patients

    PubMed Central

    Vrana, Andrea; Hotz-Boendermaker, Sabina; Stämpfli, Philipp; Hänggi, Jürgen; Seifritz, Erich; Humphreys, B. Kim; Meier, Michael L.

    2015-01-01

    Chronic low back pain (chronic LBP) is both debilitating for patients but also a major burden on the health care system. Previous studies reported various maladaptive structural and functional changes among chronic LBP patients on spine- and supraspinal levels including behavioral alterations. However, evidence for cortical reorganization in the sensorimotor system of chronic LBP patients is scarce. Motor Imagery (MI) is suitable for investigating the cortical sensorimotor network as it serves as a proxy for motor execution. Our aim was to investigate differential MI-driven cortical processing in chronic LBP compared to healthy controls (HC) by means of functional magnetic resonance imaging (fMRI). Twenty-nine subjects (15 chronic LBP patients, 14 HC) were included in the current study. MI stimuli consisted of randomly presented video clips showing every-day activities involving different whole-body movements as well as walking on even ground and walking downstairs and upstairs. Guided by the video clips, subjects had to perform MI of these activities, subsequently rating the vividness of their MI performance. Brain activity analysis revealed that chronic LBP patients exhibited significantly reduced activity compared to HC subjects in MI-related brain regions, namely the left supplementary motor area and right superior temporal sulcus. Furthermore, psycho-physiological-interaction analysis yielded significantly enhanced functional connectivity (FC) between various MI-associated brain regions in chronic LBP patients indicating diffuse and non-specific changes in FC. Current results demonstrate initial findings about differences in MI-driven cortical processing in chronic LBP pointing towards reorganization processes in the sensorimotor network. PMID:26569602

  9. Longitudinal Changes in the Motor Learning-Related Brain Activation Response in Presymptomatic Huntington's Disease

    PubMed Central

    Holtbernd, Florian; Tang, Chris C.; Feigin, Andrew; Dhawan, Vijay; Ghilardi, Maria Felice; Paulsen, Jane S.; Guttman, Mark; Eidelberg, David

    2016-01-01

    Neurocognitive decline, including deficits in motor learning, occurs in the presymptomatic phase of Huntington’s disease (HD) and precedes the onset of motor symptoms. Findings from recent neuroimaging studies have linked these deficits to alterations in fronto-striatal and fronto-parietal brain networks. However, little is known about the temporal dynamics of these networks when subjects approach phenoconversion. Here, 10 subjects with presymptomatic HD were scanned with 15O-labeled water at baseline and again 1.5 years later while performing a motor sequence learning task and a kinematically matched control task. Spatial covariance analysis was utilized to characterize patterns of change in learning-related neural activation occurring over time in these individuals. Pattern expression was compared to corresponding values in 10 age-matched healthy control subjects. Spatial covariance analysis revealed significant longitudinal changes in the expression of a specific learning-related activation pattern characterized by increasing activity in the right orbitofrontal cortex, with concurrent reductions in the right medial prefrontal and posterior cingulate regions, the left insula, left precuneus, and left cerebellum. Changes in the expression of this pattern over time correlated with baseline measurements of disease burden and learning performance. The network changes were accompanied by modest improvement in learning performance that took place concurrently in the gene carriers. The presence of increased network activity in the setting of stable task performance is consistent with a discrete compensatory mechanism. The findings suggest that this effect is most pronounced in the late presymptomatic phase of HD, as subjects approach clinical onset. PMID:27192167

  10. Human Motor Cortical Activity Is Selectively Phase-Entrained on Underlying Rhythms

    PubMed Central

    Miller, Kai J.; Hermes, Dora; Honey, Christopher J.; Hebb, Adam O.; Ramsey, Nick F.; Knight, Robert T.; Ojemann, Jeffrey G.; Fetz, Eberhard E.

    2012-01-01

    The functional significance of electrical rhythms in the mammalian brain remains uncertain. In the motor cortex, the 12–20 Hz beta rhythm is known to transiently decrease in amplitude during movement, and to be altered in many motor diseases. Here we show that the activity of neuronal populations is phase-coupled with the beta rhythm on rapid timescales, and describe how the strength of this relation changes with movement. To investigate the relationship of the beta rhythm to neuronal dynamics, we measured local cortical activity using arrays of subdural electrocorticographic (ECoG) electrodes in human patients performing simple movement tasks. In addition to rhythmic brain processes, ECoG potentials also reveal a spectrally broadband motif that reflects the aggregate neural population activity beneath each electrode. During movement, the amplitude of this broadband motif follows the dynamics of individual fingers, with somatotopically specific responses for different fingers at different sites on the pre-central gyrus. The 12–20 Hz beta rhythm, in contrast, is widespread as well as spatially coherent within sulcal boundaries and decreases in amplitude across the pre- and post-central gyri in a diffuse manner that is not finger-specific. We find that the amplitude of this broadband motif is entrained on the phase of the beta rhythm, as well as rhythms at other frequencies, in peri-central cortex during fixation. During finger movement, the beta phase-entrainment is diminished or eliminated. We suggest that the beta rhythm may be more than a resting rhythm, and that this entrainment may reflect a suppressive mechanism for actively gating motor function. PMID:22969416

  11. Human motor cortical activity is selectively phase-entrained on underlying rhythms.

    PubMed

    Miller, Kai J; Hermes, Dora; Honey, Christopher J; Hebb, Adam O; Ramsey, Nick F; Knight, Robert T; Ojemann, Jeffrey G; Fetz, Eberhard E

    2012-01-01

    The functional significance of electrical rhythms in the mammalian brain remains uncertain. In the motor cortex, the 12-20 Hz beta rhythm is known to transiently decrease in amplitude during movement, and to be altered in many motor diseases. Here we show that the activity of neuronal populations is phase-coupled with the beta rhythm on rapid timescales, and describe how the strength of this relation changes with movement. To investigate the relationship of the beta rhythm to neuronal dynamics, we measured local cortical activity using arrays of subdural electrocorticographic (ECoG) electrodes in human patients performing simple movement tasks. In addition to rhythmic brain processes, ECoG potentials also reveal a spectrally broadband motif that reflects the aggregate neural population activity beneath each electrode. During movement, the amplitude of this broadband motif follows the dynamics of individual fingers, with somatotopically specific responses for different fingers at different sites on the pre-central gyrus. The 12-20 Hz beta rhythm, in contrast, is widespread as well as spatially coherent within sulcal boundaries and decreases in amplitude across the pre- and post-central gyri in a diffuse manner that is not finger-specific. We find that the amplitude of this broadband motif is entrained on the phase of the beta rhythm, as well as rhythms at other frequencies, in peri-central cortex during fixation. During finger movement, the beta phase-entrainment is diminished or eliminated. We suggest that the beta rhythm may be more than a resting rhythm, and that this entrainment may reflect a suppressive mechanism for actively gating motor function. PMID:22969416

  12. Differential Neural Processing during Motor Imagery of Daily Activities in Chronic Low Back Pain Patients.

    PubMed

    Vrana, Andrea; Hotz-Boendermaker, Sabina; Stämpfli, Philipp; Hänggi, Jürgen; Seifritz, Erich; Humphreys, B Kim; Meier, Michael L

    2015-01-01

    Chronic low back pain (chronic LBP) is both debilitating for patients but also a major burden on the health care system. Previous studies reported various maladaptive structural and functional changes among chronic LBP patients on spine- and supraspinal levels including behavioral alterations. However, evidence for cortical reorganization in the sensorimotor system of chronic LBP patients is scarce. Motor Imagery (MI) is suitable for investigating the cortical sensorimotor network as it serves as a proxy for motor execution. Our aim was to investigate differential MI-driven cortical processing in chronic LBP compared to healthy controls (HC) by means of functional magnetic resonance imaging (fMRI). Twenty-nine subjects (15 chronic LBP patients, 14 HC) were included in the current study. MI stimuli consisted of randomly presented video clips showing every-day activities involving different whole-body movements as well as walking on even ground and walking downstairs and upstairs. Guided by the video clips, subjects had to perform MI of these activities, subsequently rating the vividness of their MI performance. Brain activity analysis revealed that chronic LBP patients exhibited significantly reduced activity compared to HC subjects in MI-related brain regions, namely the left supplementary motor area and right superior temporal sulcus. Furthermore, psycho-physiological-interaction analysis yielded significantly enhanced functional connectivity (FC) between various MI-associated brain regions in chronic LBP patients indicating diffuse and non-specific changes in FC. Current results demonstrate initial findings about differences in MI-driven cortical processing in chronic LBP pointing towards reorganization processes in the sensorimotor network. PMID:26569602

  13. Common prefrontal regions activate during self-control of craving, emotion, and motor impulses in smokers

    PubMed Central

    Tabibnia, Golnaz; Creswell, J. David; Kraynak, Thomas; Westbrook, Cecilia; Julson, Erica; Tindle, Hilary A.

    2014-01-01

    It has been posited that self-regulation of behaviors, emotions, and temptations may all rely on a common resource. Recent reviews suggest this common resource may include the inferior frontal cortex (IFC). However, to our knowledge no single functional neuroimaging study has tested this hypothesis. We obtained fMRI scans as 25 abstinent treatment-seeking cigarette smokers completed motor, affective, and craving self-control tasks before smoking cessation treatment. We identified two regions in left IFC and a region in pre-supplementary motor area (preSMA) that were commonly activated in all three tasks. Further, PPI analyses suggest that IFC may involve dissociable pathways in each self-control domain. Specifically, the IFC showed negative functional connectivity with large portions of the thalamus and precentral gyrus during motor stopping, with the insula and other portions of the thalamus during craving regulation, and potentially with a small limbic region during emotion regulation. We discuss implications for understanding self-control mechanisms. PMID:25485181

  14. Sensory-motor system identification of active perception in ecologically valid environments

    NASA Astrophysics Data System (ADS)

    Abbott, William; Thomik, Andreas; Faisal, A. Aldo

    2015-03-01

    The brain is a dynamical system mapping sensory inputs to motor actions. This relationship has been widely characterised by reductionist controlled experiments. Here we present work moving out of the lab ``into the wild'' to capture, rather than constrain, sensory inputs and motor outputs, by recording 90% of sensory inputs using head mounted eye-tracking, scene camera and microphone as well as recording 95% of skeletal motor outputs by motion tracking 51 degrees of freedom in the body and a total of 40 degrees of freedom from the hands. We can thus begin to systematically characterise the perception-action loop through system identification. This enables use to evaluate classical relationships in ecologically valid settings and behaviours including 3 daily scenarios: breakfast in the kitchen, evening chores and activities and in-door ambulation . This level of data richness (97 DOF, 60Hz), coupled with the extensive recordings of natural perceptual and behavioural data (total > 30 hrs, 10 subjects) enables us to answer general questions of how lab tasks and protocols will produce systematically different results from those found in daily life.

  15. Short report: effect of two prokinetic drugs on the electrical and motor activity of the small bowel in dogs.

    PubMed

    Defilippi, C; Gomez, E

    1993-06-01

    The effects of trimebutine and domperidone, on the electrical and motor activity of the upper small bowel in dogs, were studied simultaneously by means of a suction electrode and a manometric catheter. Trimebutine, given during phases I and II of the migratory motor complex, was followed by a period of regular spike potentials and contractions; the increased motor activity was significantly greater when the drug was given during phase II. Domperidone, when injected in phase I, was followed by an irregular pattern of spike potentials and contractions of low amplitude. By contrast, activity was not augmented when the drug was given during phase II. We conclude that the effects of drugs, such as trimebutine and domperidone, on the canine small bowel are influenced by the phase of the migratory motor complex. PMID:8364138

  16. Spontaneous activity in electromyography may differentiate certain benign lower motor neuron disease forms from amyotrophic lateral sclerosis.

    PubMed

    Jokela, Manu E; Jääskeläinen, Satu K; Sandell, Satu; Palmio, Johanna; Penttilä, Sini; Saukkonen, Annamaija; Soikkeli, Raija; Udd, Bjarne

    2015-08-15

    There is limited data on electromyography (EMG) findings in other motor neuron disorders than amyotrophic lateral sclerosis (ALS). We assessed whether the distribution of active denervation detected by EMG, i.e. fibrillations and fasciculations, differs between ALS and slowly progressive motor neuron disorders. We compared the initial EMG findings of 43 clinically confirmed, consecutive ALS patients with those of 41 genetically confirmed Late-onset Spinal Motor Neuronopathy and 14 Spinal and Bulbar Muscular Atrophy patients. Spontaneous activity was more frequently detected in the first dorsal interosseus and deltoid muscles of ALS patients than in patients with the slowly progressive motor neuron diseases. The most important observation was that absent fibrillations in the first dorsal interosseus muscle identified the benign forms with sensitivities of 66%-77% and a specificity of 93%. The distribution of active denervation may help to separate ALS from mimicking disorders at an early stage. PMID:26059445

  17. Preliminary study on safe thresholds for temporary internal carotid artery occlusion in aneurysm surgery based on motor-evoked potential monitoring

    PubMed Central

    Tanabe, Jun; Ishikawa, Tatsuya; Moroi, Junta; Suzuki, Akifumi

    2014-01-01

    Background: The study aims were to clarify safe duration for temporary vessel occlusion of the internal carotid artery (ICA) during aneurysm surgery as exactly as possible. We examined safe time duration (STD), where brain tissue exposed to ischemia will never fall into even the ischemic penumbra using intraoperative motor-evoked potential (MEP). Methods: In 45 patients, temporary occlusion of the ICA was performed with MEP. We measured STD as the duration of temporary vessel occlusion during which MEP changes did not occur. To estimate average STD, we calculated the 95% confidence interval for the population mean from sample data for STD in patients with MEP changes and in patients without changes. Results: In the proximal-control group, 4 of 38 patients (10.5%) developed intraoperative MEP changes. In 4 patients, the time to MEP change (i.e. STD) was 6.0 ± 2.5 min. STD was 3.8 ± 1.6 min in the 34 patients without changes. The average STD was 4.0 ± 0.6 min. In the trap group (proximal and distal flow control), five of seven patients (60.0%) experienced intraoperative MEP changes (STD, 2.3 ± 1.0 min). All patients in the trap group who developed MEP changes showed involvement of the anterior choroidal artery (AchA) in the trapped segment. Average STD was 2.3 ± 1.1 min when trapping involving the AchA. Conclusions: Although the study is preliminary based on the limited number of the patients, the 95% upper confidence limit for average STD was 4.6 min when the ICA was occluded proximal to the aneurysm, 3.4 min when the ICA was trapped involving the AchA. PMID:24818054

  18. Differences in cortical activity related to motor planning between experienced guitarists and non-musicians during guitar playing.

    PubMed

    Wright, David J; Holmes, Paul S; Di Russo, Francesco; Loporto, Michela; Smith, Dave

    2012-06-01

    The influence of motor skill learning on movement-related brain activity was investigated using electroencephalography. Previous research has indicated that experienced performers display movement-related cortical potentials (MRCPs) of smaller amplitude and later onset compared to novices. Unfortunately, previous studies have lacked ecological validity with experimenters recording the MRCP prior to simple motor tasks and applying the results to more complex motor skills. This study replicated previous research using an ecologically valid motor skill; recording the MRCP from a group of experienced guitarists and a control group of non-musicians while they played a simple scale on the guitar. Results indicated no difference between groups in early motor planning. In contrast, the later, negative slope and motor potential components were of smaller amplitude and the negative slope began later in the experienced guitarists. The data may indicate that, for experienced guitarists, a reduced level of effort is required during the motor preparation phase of the task. These findings have implications for musical instrument learning as well as motor skill acquisition in general. PMID:21899906

  19. Active Learning and Threshold Concepts in Multiple Testing That Can Further Develop Student Critical Statistical Thinking

    ERIC Educational Resources Information Center

    White, Desley

    2015-01-01

    Two practical activities are described, which aim to support critical thinking about statistics as they concern multiple outcomes testing. Formulae are presented in Microsoft Excel spreadsheets, which are used to calculate the inflation of error associated with the quantity of tests performed. This is followed by a decision-making exercise, where…

  20. Mephedrone ('bath salt') elicits conditioned place preference and dopamine-sensitive motor activation.

    PubMed

    Lisek, Renata; Xu, Wei; Yuvasheva, Ekaterina; Chiu, Yi-Ting; Reitz, Allen B; Liu-Chen, Lee-Yuan; Rawls, Scott M

    2012-11-01

    Abuse of a dangerous street drug called mephedrone (4-methylmethcathinone) has become commonplace in the United States. Mephedrone is hypothesized to possess abuse liability, share pharmacological properties with psychostimulants, and display toxicity that has been linked to fatalities and non-fatal overdoses. Knowledge about the pharmacology of mephedrone has been obtained primarily from surveys of drug abusers and emergency room visits rather than experimental studies. The present study used motor activity and conditioned place preference (CPP) assays to investigate behavioral effects of mephedrone. Acute mephedrone (3, 5, 10, 30 mg/kg, ip) administration increased ambulatory activity in rats. Mephedrone (5 mg/kg, ip)-induced ambulation was inhibited by pretreatment with a dopamine D1 receptor antagonist (SCH 23390) (0.5, 1, 2 mg/kg, ip) and enhanced by pretreatment with a dopamine D2 receptor antagonist (sulpiride) (2 mg/kg, ip). Rats injected for 5 days with low dose mephedrone (0.5 mg/kg, ip) and then challenged with mephedrone (0.5 mg/kg, ip) following 10 days of abstinence displayed sensitization of ambulatory activity. In CPP experiments, mephedrone (30 mg/kg, ip) conditioning elicited a preference shift in both rats and mice. The CPP and dopamine-sensitive motor activation produced by mephedrone is suggestive of abuse liability and indicates commonalities between the neuropharmacological profiles of mephedrone and established drugs of abuse. PMID:22652295

  1. Interaction between auditory and motor activities in an avian song control nucleus.

    PubMed Central

    McCasland, J S; Konishi, M

    1981-01-01

    Discrete telencephalic nuclei HVc (hyperstriatum ventrale, pars caudale) and RA (nucleus robustus archistriatalis) have been implicated by lesion studies in the control of vocalization in songbirds. We demonstrate directly the role of HVc in vocalization by presenting neuronal recordings taken from HVc of singing birds. Intracellular recordings from anesthetized birds have shown that many neurons in HVc respond to auditory stimuli. We confirm this result in the extracellular recordings from awake-behaving birds and further demonstrate responses of HVc neurons to playback of the bird's own song. The functional significance of these responses is not yet clear, but behavioral studies show that auditory feedback plays a crucial role in the development of normal song. We show that the song-correlated temporal pattern of neural activity persists even in the deaf bird. Furthermore, we show that in the normal bird, the activity pattern correlated with production of certain song elements can be clearly distinguished from the pattern of auditory responses to the same song elements. This result implies that an interaction occurs in HVc of the singing bird between motor and auditory activity. Through experiments involving playback of sound while the bird is singing, we show that the interaction consists of motor inhibition of auditory activity in HVc and that this inhibition decays slowly over a period of seconds after the song terminates. PMID:6950421

  2. Model for a flexible motor memory based on a self-active recurrent neural network.

    PubMed

    Boström, Kim Joris; Wagner, Heiko; Prieske, Markus; de Lussanet, Marc

    2013-10-01

    Using recent recurrent network architecture based on the reservoir computing approach, we propose and numerically simulate a model that is focused on the aspects of a flexible motor memory for the storage of elementary movement patterns into the synaptic weights of a neural network, so that the patterns can be retrieved at any time by simple static commands. The resulting motor memory is flexible in that it is capable to continuously modulate the stored patterns. The modulation consists in an approximately linear inter- and extrapolation, generating a large space of possible movements that have not been learned before. A recurrent network of thousand neurons is trained in a manner that corresponds to a realistic exercising scenario, with experimentally measured muscular activations and with kinetic data representing proprioceptive feedback. The network is "self-active" in that it maintains recurrent flow of activation even in the absence of input, a feature that resembles the "resting-state activity" found in the human and animal brain. The model involves the concept of "neural outsourcing" which amounts to the permanent shifting of computational load from higher to lower-level neural structures, which might help to explain why humans are able to execute learned skills in a fluent and flexible manner without the need for attention to the details of the movement. PMID:24120277

  3. Robot-assisted motor activation monitored by time-domain optical brain imaging

    NASA Astrophysics Data System (ADS)

    Steinkellner, O.; Wabnitz, H.; Schmid, S.; Steingräber, R.; Schmidt, H.; Krüger, J.; Macdonald, R.

    2011-07-01

    Robot-assisted motor rehabilitation proved to be an effective supplement to conventional hand-to-hand therapy in stroke patients. In order to analyze and understand motor learning and performance during rehabilitation it is desirable to develop a monitor to provide objective measures of the corresponding brain activity at the rehabilitation progress. We used a portable time-domain near-infrared reflectometer to monitor the hemodynamic brain response to distal upper extremity activities. Four healthy volunteers performed two different robot-assisted wrist/forearm movements, flexion-extension and pronation-supination in comparison with an unassisted squeeze ball exercise. A special headgear with four optical measurement positions to include parts of the pre- and postcentral gyrus provided a good overlap with the expected activation areas. Data analysis based on variance of time-of-flight distributions of photons through tissue was chosen to provide a suitable representation of intracerebral signals. In all subjects several of the four detection channels showed a response. In some cases indications were found of differences in localization of the activated areas for the various tasks.

  4. Motor-driven marginal band coiling promotes cell shape change during platelet activation

    PubMed Central

    Diagouraga, Boubou; Grichine, Alexei; Fertin, Arnold; Wang, Jin; Khochbin, Saadi

    2014-01-01

    Platelets float in the blood as discoid particles. Their shape is maintained by microtubules organized in a ring structure, the so-called marginal band (MB), in the periphery of resting platelets. Platelets are activated after vessel injury and undergo a major shape change known as disc to sphere transition. It has been suggested that actomyosin tension induces the contraction of the MB to a smaller ring. In this paper, we show that antagonistic microtubule motors keep the MB in its resting state. During platelet activation, dynein slides microtubules apart, leading to MB extension rather than contraction. The MB then starts to coil, thereby inducing the spherical shape of activating platelets. Newly polymerizing microtubules within the coiled MB will then take a new path to form the smaller microtubule ring, in concerted action with actomyosin tension. These results present a new view of the platelet activation mechanism and reveal principal mechanistic features underlying cellular shape changes. PMID:24421335

  5. Neural Activity during Voluntary Movements in Each Body Representation of the Intracortical Microstimulation-Derived Map in the Macaque Motor Cortex

    PubMed Central

    Kunori, Nobuo; Murata, Yumi

    2016-01-01

    In order to accurately interpret experimental data using the topographic body map identified by conventional intracortical microstimulation (ICMS), it is important to know how neurons in each division of the map respond during voluntary movements. Here we systematically investigated neuronal responses in each body representation of the ICMS map during a reach-grasp-retrieval task that involves the movements of multiple body parts. The topographic body map in the primary motor cortex (M1) generally corresponds to functional divisions of voluntary movements; neurons at the recording sites in each body representation with movement thresholds of 10 μA or less were differentially activated during the task, and the timing of responses was consistent with the movements of the body part represented. Moreover, neurons in the digit representation responded differently for the different types of grasping. In addition, the present study showed that neural activity depends on the ICMS current threshold required to elicit body movements and the location of the recording on the cortical surface. In the ventral premotor cortex (PMv), no correlation was found between the response properties of neurons and the body representation in the ICMS map. Neural responses specific to forelimb movements were often observed in the rostral part of PMv, including the lateral bank of the lower arcuate limb, in which ICMS up to 100 μA evoked no detectable movement. These results indicate that the physiological significance of the ICMS-derived maps is different between, and even within, areas M1 and PMv. PMID:27494282

  6. Axin determines cell fate by controlling the p53 activation threshold after DNA damage.

    PubMed

    Li, Qinxi; Lin, Shuyong; Wang, Xuan; Lian, Guili; Lu, Zailian; Guo, Huiling; Ruan, Ka; Wang, Yanhai; Ye, Zhiyun; Han, Jiahuai; Lin, Sheng-Cai

    2009-09-01

    Cells can undergo either cell-cycle arrest or apoptosis after genotoxic stress, based on p53 activity(1-6). Here we show that cellular fate commitment depends on Axin forming distinct complexes with Pirh2, Tip60, HIPK2 and p53. In cells treated with sublethal doses of ultra-violet (UV) radiation or doxorubicin (Dox), Pirh2 abrogates Axin-induced p53 phosphorylation at Ser 46 catalysed by HIPK2, by competing with HIPK2 for binding to Axin. However, on lethal treatment, Tip60 interacts with Axin and abrogates Pirh2-Axin binding, forming an Axin-Tip60-HIPK2-p53 complex that allows maximal p53 activation to trigger apoptosis. We also provide evidence that the ATM/ATR pathway mediates the Axin-Tip60 complex assembly. An axin mutation promotes carcinogenesis in Axin(Fu)/+ (Axin-Fused) mice, consistent with a dominantnegative role for Axin(Fu) in p53 activation. Thus, Axin is a critical determinant in p53-dependent tumour suppression in which Pirh2 and Tip60 have different roles in triggering cell-cycle arrest or apoptosis depending on the severity of genotoxic stress. PMID:19731416

  7. Differences in motor activation of voluntary and reflex cough in humans

    PubMed Central

    Lasserson, D; Mills, K; Arunachalam, R; Polkey, M; Moxham, J; Kalra, L

    2006-01-01

    Objectives To study motor activation patterns of voluntary and reflex cough adjusted for cough flow rates. Methods Surface electromyography (EMG) and cough flow rate were measured in 10 healthy volunteers. Voluntary cough was assessed for 20 efforts in each quintile of increasing cough flow rate. Reflex cough was assessed for 25 efforts produced by nebulised l‐tartaric acid. EMG was recorded over the expiratory (rectus abdominis, obliques, lower intercostals) and accessory (trapezius, pectoralis major, deltoid, latissimus dorsi) muscles. EMG activity, burst duration and onset were compared for each quintile of voluntary cough, and between voluntary and reflex cough matched for cough flow rate. Results EMG activity and burst duration of expiratory and accessory muscles during voluntary cough increased in proportion to cough flow. Expiratory muscles had longer EMG burst duration (difference 68 ms (95% CI 34 to 102), p<0.01) and earlier onset of EMG activity (difference 44 ms (95% CI 20 to 68), p<0.0001) compared with accessory muscles. EMG activity in all muscles was increased (mean 110.2% v 56.1%, p<0.001) and burst duration (mean 206 ms v 280 ms, p = 0.013) decreased in reflex cough compared with voluntary cough of equal flow rate. There were no differences in EMG onset (difference 8 ms (95% CI 25 to −9) or burst duration (difference 27 ms (95% CI 58 to −4) between expiratory and accessory muscles. Conclusions Functional organisation of motor activity differs between voluntary and reflex cough. Voluntary cough is characterised by sequential activation whereas reflex cough is associated with early and simultaneous activation of expiratory and accessory muscles. PMID:16601089

  8. Effects of Metoclopramide on Esophageal Motor Activity and Esophagogastric Junction Compliance in Healthy Volunteers

    PubMed Central

    Mikami, Hironobu; Ishimura, Norihisa; Fukazawa, Kousuke; Okada, Mayumi; Izumi, Daisuke; Shimura, Shino; Okimoto, Eiko; Aimi, Masahito; Ishihara, Shunji; Kinoshita, Yoshikazu

    2016-01-01

    Background/Aims Prokinetic drugs such as metoclopramide are frequently used as second-line therapy for patients with gastroesophageal reflux disease. However, their beneficial effects remain unclear. Esophageal motor activities and compliance of the esophagogastric junction (EGJ) are important for prevention of gastroesophageal reflux. Although metoclopramide has been reported to increase lower esophageal sphincter (LES) pressure, its effects on EGJ compliance have not been evaluated. In the present study, we investigated the effects of metoclopramide on esophageal motor activities and EGJ compliance. Methods Nine healthy male volunteers without abdominal symptoms were enrolled. Peristaltic esophageal contractions and LES pressure were examined using high-resolution esophageal manometry, while EGJ compliance was evaluated with an endoluminal functional lumen-imaging probe. After obtaining baseline values for esophageal motor activities and EGJ compliance, metoclopramide (10 mg) was intravenously administered, then all measurements were repeated at 15 minutes after administration in each subject. Results Following administration of metoclopramide, mean resting LES pressure was significantly increased as compared with the baseline (13.7 ± 9.2 vs 26.7 ± 8.8 mmHg, P < 0.05). In addition, metoclopramide significantly augmented peristaltic contractions, especially in the distal esophageal segment (P < 0.05). On the other hand, distensibility index did not change after administration (4.5 ± 0.5 vs 4.1 ± 0.5 mm2/mmHg), suggesting no significant effect of metoclopramide on EGJ compliance. Conclusions Metoclopramide augmented esophageal contractions without changing EGJ compliance in healthy adults. PMID:26507875

  9. [Quantitative estimation of connection of the heart rate rhythm with motor activity in rat fetuses].

    PubMed

    Vdovichenko, N D; Timofeeva, O P; Bursian, A V

    2014-01-01

    In rat fetuses at E17-20 with preserved placental circulation with use of mathematical analysis there were revealed value and character of connections of slow wave oscillations of the heart rhythm with motor activity for 30 min of observation. In the software "PowerGraph 3.3.8", normalization and filtration of the studied signals were performed at three frequency diapasons: D1 - 0.02-0.2 Hz (5-50 s), D2 - 0.0083-0.02 Hz (50 s-2 min), and D3 - 0.0017-0.0083 Hz (2-10 min). The EMG curves filtrated by diapasons or piezograms were compared with periodograms in the corresponding diapasons of the heart rhythm variations. In the software "Origin 8.0", quantitative estimation of the degree of intersystemic interrelations for each frequency diapason was performed by Pearson correlation of coefficient, by the correlation connection value, and by the time shift of maximum of cross-correlation function. It has been established that in the frequency D1, regardless of age, the connection of heart rhythm oscillations with motor activity is expressed weakly. In the frequency diapason D2, the connection in most cases is located in the zone of weak and moderate correlations. In the multiminute diapason (D3), the connection is more pronounced. The number of animals that have a significant value of the correlation connection rises. The fetal MA fires in the decasecond diapason in all age groups are accompanied by short-time decelerations of the heart rhythms. In the minute diapason, there is observed a transition from positive connections at E17 and E18 to the negative ones at E19-20. Results of the study are considered in association with age-related changes of ratios of positive and negative oscillations of the heart rhythm change depending on the character of motor activity. PMID:25486813

  10. Chronic hyperhydration and hematological changes in trained subjects during prolonged restriction of motor activity

    NASA Astrophysics Data System (ADS)

    Zorbas, Yan G.; Yaroshenko, Michael N.; Federenko, Youri F.

    1995-08-01

    The objective of this investigation was to evaluate the effect of a daily intake of fluid and salt supplementation (FSS) on the hemoglobin content of endurance trained athletes during hypokinesia (decreased number of steps from 10,000 to 3000 steps per day). The studies were performed on 30 long-distance runners who had a VO 2max average of 66 ml kg -1 min -1 and were in the age range of 19-24 years. Prior to their exposure to hypokinesia (HK) of 364 days, all volunteers were on an average of 10,000 steps per day. All volunteers were divided into three equal groups: the first group underwent normal ambulatory life (control subjects), the second group was kept under continuous restriction of motor activity (hypokinetic subjects) and the third group was placed under continuous restriction of motor activity and consumed 26 ml water kg -1 body weight daily and 0.1 g sodium chloride kg -1 body weight in the form of supplementation (hyperhydrated subjects). For simulation of the hypokinetic effect, the number of steps taken per day by the second and third groups of volunteers was restricted to an average of 3000. During the hypokinetic period we determined reticulocytes (Rt), hemoglobin (Hb), hematocrit (Hct), plasma volume (PV), red blood cell (RBC) mass and VO 2max. In hyperhydrated volunteers the content of Hb and Hct decreased significantly, while PV, RBC mass and Rt count increased significantly. In hypokinetic volunteers Hb and Hct increased, while PV, RBC and Rt decreased significantly. It was concluded that chronic hyperhydration may be used to attentuate an increase in the Hb content of physically conditioned subjects during prolonged restriction of motor activity.

  11. Motor control or graded activity exercises for chronic low back pain? A randomised controlled trial

    PubMed Central

    Macedo, Luciana G; Latimer, Jane; Maher, Chris G; Hodges, Paul W; Nicholas, Michael; Tonkin, Lois; McAuley, James H; Stafford, Ryan

    2008-01-01

    Background Chronic low back pain remains a major health problem in Australia and around the world. Unfortunately the majority of treatments for this condition produce small effects because not all patients respond to each treatment. It appears that only 25–50% of patients respond to exercise. The two most popular types of exercise for low back pain are graded activity and motor control exercises. At present however, there are no guidelines to help clinicians select the best treatment for a patient. As a result, time and money are wasted on treatments which ultimately fail to help the patient. Methods This paper describes the protocol of a randomised clinical trial comparing the effects of motor control exercises with a graded activity program in the treatment of chronic non specific low back pain. Further analysis will identify clinical features that may predict a patient's response to each treatment. One hundred and seventy two participants will be randomly allocated to receive either a program of motor control exercises or graded activity. Measures of outcome will be obtained at 2, 6 and 12 months after randomisation. The primary outcomes are: pain (average pain intensity over the last week) and function (patient-specific functional scale) at 2 and 6 months. Potential treatment effect modifiers will be measured at baseline. Discussion This trial will not only evaluate which exercise approach is more effective in general for patients will chronic low back pain, but will also determine which exercise approach is best for an individual patient. Trial registration number ACTRN12607000432415 PMID:18454877

  12. Thresholds of copper phytotoxicity in field-collected agricultural soils exposed to copper mining activities in Chile.

    PubMed

    Verdejo, José; Ginocchio, Rosanna; Sauvé, Sébastien; Salgado, Eduardo; Neaman, Alexander

    2015-12-01

    It has been argued that the identification of the phytotoxic metal thresholds in soil should be based on field-collected soil rather than on artificially-contaminated soils. However, the use of field-collected soils presents several difficulties for interpretation because of mixed contamination and unavoidable covariance of metal contamination with other soil properties that affect plant growth. The objective of this study was to estimate thresholds of copper phytotoxicity in topsoils of 27 agricultural areas historically contaminated by mining activities in Chile. We performed emergence and early growth (21 days) tests (OECD 208 and ISO 11269-2) with perennial ryegrass (Lolium perenne L.). The total Cu content in soils was the best predictor of plant growth and shoot Cu concentrations, while soluble Cu and pCu(2+) did not well correlate with these biological responses. The effects of Pb, Zn, and As on plant responses were not significant, suggesting that Cu is a metal of prime concern for plant growth in soils exposed to copper mining activities in Chile. The effects of soil nutrient availability and shoot nutrient concentrations on ryegrass response were not significant. It was possible to determine EC10, EC25 and EC50 of total Cu in the soil of 327 mg kg(-1), 735 mg kg(-1) and 1144 mg kg(-1), respectively, using the shoot length as a response variable. However, the derived 95% confidence intervals for EC10, EC25 and EC50 values of total soil Cu were wide, and thus not allowing a robust assessment of metal toxicity for agricultural crops, based on total soil Cu concentrations. Thus, plant tests might need to be performed for metal toxicity assessment. This study suggests shoot length of ryegrass as a robust response variable for metal toxicity assessment in contaminated soils with different nutrient availability. PMID:26233921

  13. Casein kinase 1 controls the activation threshold of an α-arrestin by multisite phosphorylation of the interdomain hinge

    PubMed Central

    Herrador, Antonio; Livas, Daniela; Soletto, Lucía; Becuwe, Michel; Léon, Sébastien; Vincent, Olivier

    2015-01-01

    α-Arrestins play a key role as trafficking adaptors in both yeast and mammals. The yeast Rim8/Art9 α-arrestin mediates the recruitment of endosomal sorting complex required for transport (ESCRT) to the seven-transmembrane protein Rim21 in the ambient pH signaling RIM pathway. ESCRT is believed to function as a signaling platform that enables the proteolytic activation of the Rim101 transcription factor upon external alkalization. Here we provide evidence that the pH signal promotes the stable association of Rim8 with Rim21 at the plasma membrane. We show that Rim8 is phosphorylated in a pH-independent but Rim21-dependent manner by the plasma membrane–associated casein kinase 1 (CK1). We further show that this process involves a cascade of phosphorylation events within the hinge region connecting the arrestin domains. Strikingly, loss of casein kinase 1 activity causes constitutive activation of the RIM pathway, and, accordingly, pH signaling is activated in a phosphodeficient Rim8 mutant and impaired in the corresponding phosphomimetic mutant. Our results indicate that Rim8 phosphorylation prevents its accumulation at the plasma membrane at acidic pH and thereby inhibits RIM signaling. These findings support a model in which CK1-mediated phosphorylation of Rim8 contributes to setting a signaling threshold required to inhibit the RIM pathway at acidic pH. PMID:25851600

  14. A threshold level of NFATc1 activity facilitates thymocyte differentiation and opposes notch-driven leukaemia development.

    PubMed

    Klein-Hessling, Stefan; Rudolf, Ronald; Muhammad, Khalid; Knobeloch, Klaus-Peter; Maqbool, Muhammad Ahmad; Cauchy, Pierre; Andrau, Jean-Christophe; Avots, Andris; Talora, Claudio; Ellenrieder, Volker; Screpanti, Isabella; Serfling, Edgar; Patra, Amiya Kumar

    2016-01-01

    NFATc1 plays a critical role in double-negative thymocyte survival and differentiation. However, the signals that regulate Nfatc1 expression are incompletely characterized. Here we show a developmental stage-specific differential expression pattern of Nfatc1 driven by the distal (P1) or proximal (P2) promoters in thymocytes. Whereas, preTCR-negative thymocytes exhibit only P2 promoter-derived Nfatc1β expression, preTCR-positive thymocytes express both Nfatc1β and P1 promoter-derived Nfatc1α transcripts. Inducing NFATc1α activity from P1 promoter in preTCR-negative thymocytes, in addition to the NFATc1β from P2 promoter impairs thymocyte development resulting in severe T-cell lymphopenia. In addition, we show that NFATc1 activity suppresses the B-lineage potential of immature thymocytes, and consolidates their differentiation to T cells. Further, in the pTCR-positive DN3 cells, a threshold level of NFATc1 activity is vital in facilitating T-cell differentiation and to prevent Notch3-induced T-acute lymphoblastic leukaemia. Altogether, our results show NFATc1 activity is crucial in determining the T-cell fate of thymocytes. PMID:27312418

  15. Casein kinase 1 controls the activation threshold of an α-arrestin by multisite phosphorylation of the interdomain hinge.

    PubMed

    Herrador, Antonio; Livas, Daniela; Soletto, Lucía; Becuwe, Michel; Léon, Sébastien; Vincent, Olivier

    2015-06-01

    α-Arrestins play a key role as trafficking adaptors in both yeast and mammals. The yeast Rim8/Art9 α-arrestin mediates the recruitment of endosomal sorting complex required for transport (ESCRT) to the seven-transmembrane protein Rim21 in the ambient pH signaling RIM pathway. ESCRT is believed to function as a signaling platform that enables the proteolytic activation of the Rim101 transcription factor upon external alkalization. Here we provide evidence that the pH signal promotes the stable association of Rim8 with Rim21 at the plasma membrane. We show that Rim8 is phosphorylated in a pH-independent but Rim21-dependent manner by the plasma membrane-associated casein kinase 1 (CK1). We further show that this process involves a cascade of phosphorylation events within the hinge region connecting the arrestin domains. Strikingly, loss of casein kinase 1 activity causes constitutive activation of the RIM pathway, and, accordingly, pH signaling is activated in a phosphodeficient Rim8 mutant and impaired in the corresponding phosphomimetic mutant. Our results indicate that Rim8 phosphorylation prevents its accumulation at the plasma membrane at acidic pH and thereby inhibits RIM signaling. These findings support a model in which CK1-mediated phosphorylation of Rim8 contributes to setting a signaling threshold required to inhibit the RIM pathway at acidic pH. PMID:25851600

  16. A threshold level of NFATc1 activity facilitates thymocyte differentiation and opposes notch-driven leukaemia development

    PubMed Central

    Klein-Hessling, Stefan; Rudolf, Ronald; Muhammad, Khalid; Knobeloch, Klaus-Peter; Maqbool, Muhammad Ahmad; Cauchy, Pierre; Andrau, Jean-Christophe; Avots, Andris; Talora, Claudio; Ellenrieder, Volker; Screpanti, Isabella; Serfling, Edgar; Patra, Amiya Kumar

    2016-01-01

    NFATc1 plays a critical role in double-negative thymocyte survival and differentiation. However, the signals that regulate Nfatc1 expression are incompletely characterized. Here we show a developmental stage-specific differential expression pattern of Nfatc1 driven by the distal (P1) or proximal (P2) promoters in thymocytes. Whereas, preTCR-negative thymocytes exhibit only P2 promoter-derived Nfatc1β expression, preTCR-positive thymocytes express both Nfatc1β and P1 promoter-derived Nfatc1α transcripts. Inducing NFATc1α activity from P1 promoter in preTCR-negative thymocytes, in addition to the NFATc1β from P2 promoter impairs thymocyte development resulting in severe T-cell lymphopenia. In addition, we show that NFATc1 activity suppresses the B-lineage potential of immature thymocytes, and consolidates their differentiation to T cells. Further, in the pTCR-positive DN3 cells, a threshold level of NFATc1 activity is vital in facilitating T-cell differentiation and to prevent Notch3-induced T-acute lymphoblastic leukaemia. Altogether, our results show NFATc1 activity is crucial in determining the T-cell fate of thymocytes. PMID:27312418

  17. Primary motor cortex activity reduction under the regulation of SMA by real-time fMRI

    NASA Astrophysics Data System (ADS)

    Guo, Jia; Zhao, Xiaojie; Li, Yi; Yao, Li; Chen, Kewei

    2012-03-01

    Real-time fMRI (rtfMRI) is a new technology which allows human subjects to observe and control their own BOLD signal change from one or more localized brain regions during scanning. Current rtfMRI-neurofeedback studies mainly focused on the target region itself without considering other related regions influenced by the real-time feedback. However, there always exits important directional influence between many of cooperative regions. On the other hand, rtfMRI based on motor imagery mainly aimed at somatomotor cortex or primary motor area, whereas supplement motor area (SMA) was a relatively more integrated and pivotal region. In this study, we investigated whether the activities of SMA can be controlled utilizing different motor imagery strategies, and whether there exists any possible impact on an unregulated but related region, primary motor cortex (M1). SMA was first localized using overt finger tapping task, the activities of SMA were feedback to subjects visually on line during each of two subsequent imagery motor movement sessions. All thirteen healthy participants were found to be able to successfully control their SMA activities by self-fit imagery strategies which involved no actual motor movements. The activation of right M1 was also found to be significantly reduced in both intensity and extent with the neurofeedback process targeted at SMA, suggestive that not only the part of motor cortex activities were influenced under the regulation of a key region SMA, but also the increased difference between SMA and M1 might reflect the potential learning effect.

  18. Assessing the feasibility of time-resolved fNIRS to detect brain activity during motor imagery

    NASA Astrophysics Data System (ADS)

    Abdalmalak, Androu; Milej, Daniel; Diop, Mamadou; Naci, Lorina; Owen, Adrian M.; St. Lawrence, Keith

    2016-03-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical technique for detecting brain activity, which has been previously used during motor and motor executive tasks. There is an increasing interest in using fNIRS as a brain computer interface (BCI) for patients who lack the physical, but not the mental, ability to respond to commands. The goal of this study is to assess the feasibility of time-resolved fNIRS to detect brain activity during motor imagery. Stability tests were conducted to ensure the temporal stability of the signal, and motor imagery data were acquired on healthy subjects. The NIRS probes were placed on the scalp over the premotor cortex (PMC) and supplementary motor area (SMA), as these areas are responsible for motion planning. To confirm the fNIRS results, subjects underwent functional magnetic resonance imaging (fMRI) while performing the same task. Seven subjects have participated to date, and significant activation in the SMA and/or the PMC during motor imagery was detected by both fMRI and fNIRS in 4 of the 7 subjects. No activation was detected by either technique in the remaining three participants, which was not unexpected due to the nature of the task. The agreement between the two imaging modalities highlights the potential of fNIRS as a BCI, which could be adapted for bedside studies of patients with disorders of consciousness.

  19. Spinal adenosine A2a receptor activation elicits long-lasting phrenic motor facilitation.

    PubMed

    Golder, Francis J; Ranganathan, Lavanya; Satriotomo, Irawan; Hoffman, Michael; Lovett-Barr, Mary Rachael; Watters, Jyoti J; Baker-Herman, Tracy L; Mitchell, Gordon S

    2008-02-27

    Acute intermittent hypoxia elicits a form of spinal, brain-derived neurotrophic factor (BDNF)-dependent respiratory plasticity known as phrenic long-term facilitation. Ligands that activate G(s)-protein-coupled receptors, such as the adenosine 2a receptor, mimic the effects of neurotrophins in vitro by transactivating their high-affinity receptor tyrosine kinases, the Trk receptors. Thus, we hypothesized that A2a receptor agonists would elicit phrenic long-term facilitation by mimicking the effects of BDNF on TrkB receptors. Here we demonstrate that spinal A2a receptor agonists transactivate TrkB receptors in the rat cervical spinal cord near phrenic motoneurons, thus inducing long-lasting (hours) phrenic motor facilitation. A2a receptor activation increased phosphorylation and new synthesis of an immature TrkB protein, induced TrkB signaling through Akt, and strengthened synaptic pathways to phrenic motoneurons. RNA interference targeting TrkB mRNA demonstrated that new TrkB protein synthesis is necessary for A2a-induced phrenic motor facilitation. A2a receptor activation also increased breathing in unanesthetized rats, and improved breathing in rats with cervical spinal injuries. Thus, small, highly permeable drugs (such as adenosine receptor agonists) that transactivate TrkB receptors may provide an effective therapeutic strategy in the treatment of patients with ventilatory control disorders, such as obstructive sleep apnea, or respiratory insufficiency after spinal injury or during neurodegenerative diseases. PMID:18305238

  20. Vision of the active limb impairs bimanual motor tracking in young and older adults

    PubMed Central

    Boisgontier, Matthieu P.; Van Halewyck, Florian; Corporaal, Sharissa H. A.; Willacker, Lina; Van Den Bergh, Veerle; Beets, Iseult A. M.; Levin, Oron; Swinnen, Stephan P.

    2014-01-01

    Despite the intensive investigation of bimanual coordination, it remains unclear how directing vision toward either limb influences performance, and whether this influence is affected by age. To examine these questions, we assessed the performance of young and older adults on a bimanual tracking task in which they matched motor-driven movements of their right hand (passive limb) with their left hand (active limb) according to in-phase and anti-phase patterns. Performance in six visual conditions involving central vision, and/or peripheral vision of the active and/or passive limb was compared to performance in a no vision condition. Results indicated that directing central vision to the active limb consistently impaired performance, with higher impairment in older than young adults. Conversely, directing central vision to the passive limb improved performance in young adults, but less consistently in older adults. In conditions involving central vision of one limb and peripheral vision of the other limb, similar effects were found to those for conditions involving central vision of one limb only. Peripheral vision alone resulted in similar or impaired performance compared to the no vision (NV) condition. These results indicate that the locus of visual attention is critical for bimanual motor control in young and older adults, with older adults being either more impaired or less able to benefit from a given visual condition. PMID:25452727

  1. Distinct activation thresholds of human conventional and innate-like memory T cells

    PubMed Central

    Slichter, Chloe K.; McDavid, Andrew; Miller, Hannah W.; Finak, Greg; Seymour, Brenda J.; McNevin, John P.; Diaz, Gabriela; Czartoski, Julie L.; McElrath, M. Juliana; Gottardo, Raphael; Prlic, Martin

    2016-01-01

    Conventional memory CD8+ T cells and mucosal-associated invariant T cells (MAIT cells) are found in blood, liver, and mucosal tissues and have similar effector potential following activation, specifically expression of IFN-γ and granzyme B. To better understand each subset’s unique contributions to immunity and pathology, we interrogated inflammation- and TCR-driven activation requirements using human memory CD8+ T and MAIT cells isolated from blood and mucosal tissue biopsies in ex vivo functional assays and single cell gene expression experiments. We found that MAIT cells had a robust IFN-γ and granzyme B response to inflammatory signals but limited responsiveness when stimulated directly via their TCR. Importantly, this is not due to an overall hyporesponsiveness to TCR signals. When delivered together, TCR and inflammatory signals synergize to elicit potent effector function in MAIT cells. This unique control of effector function allows MAIT cells to respond to the same TCR signal in a dichotomous and situation-specific manner. We propose that this could serve to prevent responses to antigen in noninflamed healthy mucosal tissue, while maintaining responsiveness and great sensitivity to inflammation-eliciting infections. We discuss the implications of these findings in context of inflammation-inducing damage to tissues such as BM transplant conditioning or HIV infection. PMID:27331143

  2. Broadband activation by white-opsin lowers intensity threshold for cellular stimulation

    PubMed Central

    Batabyal, Subrata; Cervenka, Gregory; Birch, David; Kim, Young-tae; Mohanty, Samarendra

    2015-01-01

    Photoreceptors, which initiate the conversion of ambient light to action potentials via retinal circuitry, degenerate in retinal diseases such as retinitis pigmentosa and age related macular degeneration leading to loss of vision. Current prosthetic devices using arrays consisting of electrodes or LEDs (for optogenetic activation of conventional narrow-band opsins) have limited spatial resolution and can cause damage to retinal circuits by mechanical or photochemical (by absorption of intense narrow band light) means. Here, we describe a broad-band light activatable white-opsin for generating significant photocurrent at white light intensity levels close to ambient daylight conditions. White-opsin produced an order of magnitude higher photocurrent in response to white light as compared to narrow-band opsin channelrhodopsin-2, while maintaining the ms-channel kinetics. High fidelity of peak-photocurrent (both amplitude and latency) of white-opsin in response to repetitive white light stimulation of varying pulse width was observed. The significantly lower intensity stimulation required for activating white-opsin sensitized cells may facilitate ambient white light-based restoration of vision for patients with widespread photoreceptor degeneration. PMID:26658483

  3. Speed control for synchronous motors

    NASA Technical Reports Server (NTRS)

    Packard, H.; Schott, J.

    1981-01-01

    Feedback circuit controls fluctuations in speed of synchronous ac motor. Voltage proportional to phase angle is developed by phase detector, rectified, amplified, compared to threshold, and reapplied positively or negatively to motor excitation circuit. Speed control reduces wow and flutter of audio turntables and tape recorders, and enhances hunting in gyroscope motors.

  4. Two new competing pathways establish the threshold for cyclin-B–Cdk1 activation at the meiotic G2/M transition

    PubMed Central

    Aono, Ryota; Hanada, Shin-ichiro; Okumura, Eiichi; Kishimoto, Takeo

    2016-01-01

    ABSTRACT Extracellular ligands control biological phenomena. Cells distinguish physiological stimuli from weak noise stimuli by establishing a ligand-concentration threshold. Hormonal control of the meiotic G2/M transition in oocytes is essential for reproduction. However, the mechanism for threshold establishment is unclear. In starfish oocytes, maturation-inducing hormones activate the PI3K–Akt pathway through the Gβγ complex of heterotrimeric G-proteins. Akt directly phosphorylates both Cdc25 phosphatase and Myt1 kinase, resulting in activation of cyclin-B–Cdk1, which then induces meiotic G2/M transition. Here, we show that cyclin-B–Cdk1 is partially activated after subthreshold hormonal stimuli, but this triggers negative feedback, resulting in dephosphorylation of Akt sites on Cdc25 and Myt1, thereby canceling the signal. We also identified phosphatase activity towards Akt substrates that exists independent of stimuli. In contrast to these negative regulatory activities, an atypical Gβγ-dependent pathway enhances PI3K–Akt-dependent phosphorylation. Based on these findings, we propose a model for threshold establishment in which hormonal dose-dependent competition between these new pathways establishes a threshold; the atypical Gβγ-pathway becomes predominant over Cdk-dependent negative feedback when the stimulus exceeds this threshold. Our findings provide a regulatory connection between cell cycle and signal transduction machineries. PMID:27390173

  5. The activation of IgM- or isotype-switched IgG- and IgE-BCR exhibits distinct mechanical force sensitivity and threshold

    PubMed Central

    Wan, Zhengpeng; Chen, Xiangjun; Chen, Haodong; Ji, Qinghua; Chen, Yingjia; Wang, Jing; Cao, Yiyun; Wang, Fei; Lou, Jizhong; Tang, Zhuo; Liu, Wanli

    2015-01-01

    B lymphocytes use B cell receptors (BCRs) to sense the physical features of the antigens. However, the sensitivity and threshold for the activation of BCRs resulting from the stimulation by mechanical forces are unknown. Here, we addressed this question using a double-stranded DNA-based tension gauge tether system serving as a predefined mechanical force gauge ranging from 12 to 56 pN. We observed that IgM-BCR activation is dependent on mechanical forces and exhibits a multi-threshold effect. In contrast, the activation of isotype-switched IgG- or IgE-BCR only requires a low threshold of less than 12 pN, providing an explanation for their rapid activation in response to antigen stimulation. Mechanistically, we found that the cytoplasmic tail of the IgG-BCR heavy chain is both required and sufficient to account for the low mechanical force threshold. These results defined the mechanical force sensitivity and threshold that are required to activate different isotyped BCRs. DOI: http://dx.doi.org/10.7554/eLife.06925.001 PMID:26258882

  6. Two new competing pathways establish the threshold for cyclin-B-Cdk1 activation at the meiotic G2/M transition.

    PubMed

    Hiraoka, Daisaku; Aono, Ryota; Hanada, Shin-Ichiro; Okumura, Eiichi; Kishimoto, Takeo

    2016-08-15

    Extracellular ligands control biological phenomena. Cells distinguish physiological stimuli from weak noise stimuli by establishing a ligand-concentration threshold. Hormonal control of the meiotic G2/M transition in oocytes is essential for reproduction. However, the mechanism for threshold establishment is unclear. In starfish oocytes, maturation-inducing hormones activate the PI3K-Akt pathway through the Gβγ complex of heterotrimeric G-proteins. Akt directly phosphorylates both Cdc25 phosphatase and Myt1 kinase, resulting in activation of cyclin-B-Cdk1, which then induces meiotic G2/M transition. Here, we show that cyclin-B-Cdk1 is partially activated after subthreshold hormonal stimuli, but this triggers negative feedback, resulting in dephosphorylation of Akt sites on Cdc25 and Myt1, thereby canceling the signal. We also identified phosphatase activity towards Akt substrates that exists independent of stimuli. In contrast to these negative regulatory activities, an atypical Gβγ-dependent pathway enhances PI3K-Akt-dependent phosphorylation. Based on these findings, we propose a model for threshold establishment in which hormonal dose-dependent competition between these new pathways establishes a threshold; the atypical Gβγ-pathway becomes predominant over Cdk-dependent negative feedback when the stimulus exceeds this threshold. Our findings provide a regulatory connection between cell cycle and signal transduction machineries. PMID:27390173

  7. VARIABILITY IN THE PREWEANLING ONTOGENY OF MOTOR ACTIVITY IN RATS: INFLUENCE OF DEVICE, TEST DAY, AND RAT SUPPLIER.

    EPA Science Inventory

    Current developmental neurotoxicity testing guidelines include evaluation of preweanling motor activity in rats. The ontogeny of activity levels as well as within-session habituation may be measured by repeatedly testing subjects at specific days of age. Activity levels are i...

  8. Corticospinal activity evoked and modulated by non-invasive stimulation of the intact human motor cortex.

    PubMed

    Di Lazzaro, Vincenzo; Rothwell, John C

    2014-10-01

    A number of methods have been developed recently that stimulate the human brain non-invasively through the intact scalp. The most common are transcranial magnetic stimulation (TMS), transcranial electric stimulation (TES) and transcranial direct current stimulation (TDCS). They are widely used to probe function and connectivity of brain areas as well as therapeutically in a variety of conditions such as depression or stroke. They are much less focal than conventional invasive methods which use small electrodes placed on or in the brain and are often thought to activate all classes of neurones in the stimulated area. However, this is not true. A large body of evidence from experiments on the motor cortex shows that non-invasive methods of brain stimulation can be surprisingly selective and that adjusting the intensity and direction of stimulation can activate different classes of inhibitory and excitatory inputs to the corticospinal output cells. Here we review data that have elucidated the action of TMS and TES, concentrating mainly on the most direct evidence available from spinal epidural recordings of the descending corticospinal volleys. The results show that it is potentially possible to test and condition specific neural circuits in motor cortex that could be affected differentially by disease, or be used in different forms of natural behaviour. However, there is substantial interindividual variability in the specificity of these protocols. Perhaps in the future it will be possible, with the advances currently being made to model the electrical fields induced in individual brains, to develop forms of stimulation that can reliably target more specific populations of neurones, and open up the internal circuitry of the motor cortex for study in behaving humans. PMID:25172954

  9. Superior Sensory, Motor, and Cognitive Performance in Elderly Individuals with Multi-Year Dancing Activities

    PubMed Central

    Kattenstroth, Jan-Christoph; Kolankowska, Izabella; Kalisch, Tobias; Dinse, Hubert R.

    2010-01-01

    Aging is associated with a progressive decline of mental and physical abilities. Considering the current demographic changes in many civilizations there is an urgent need for measures permitting an independent lifestyle into old age. The critical role of physical exercise in mediating and maintaining physical and mental fitness is well-acknowledged. Dance, in addition to physical activity, combines emotions, social interaction, sensory stimulation, motor coordination and music, thereby creating enriched environmental conditions for human individuals. Here we demonstrate the impact of multi-year (average 16.5 years) amateur dancing (AD) in a group of elderly subjects (aged 65–84 years) as compared to education-, gender- and aged-matched controls (CG) having no record of dancing or sporting activities. Besides posture and balance parameters, we tested reaction times, motor behavior, tactile and cognitive performance. In each of the different domains investigated, the AD group had a superior performance as compared to the non-dancer CG group. Analysis of individual performance revealed that the best participants of the AD group were not better than individuals of the CG group. Instead, the AD group lacked individuals showing poor performance, which was frequently observed for the CG group. This observation implies that maintaining a regular schedule of dancing into old age can preserve cognitive, motor and perceptual abilities and prevent them from degradation. We conclude that the far-reaching beneficial effects found in the AD group make dance, beyond its ability to facilitate balance and posture, a prime candidate for the preservation of everyday life competence of elderly individuals. PMID:20725636

  10. Short-term effects of integrated motor imagery practice on muscle activation and force performance.

    PubMed

    Di Rienzo, F; Blache, Y; Kanthack, T F D; Monteil, K; Collet, C; Guillot, A

    2015-10-01

    The effect of motor imagery (MI) practice on isometric force development is well-documented. However, whether practicing MI during rest periods of physical training improves the forthcoming performance remains unexplored. We involved 18 athletes in a counterbalanced design including three physical training sessions scheduled over five consecutive days. Training involved 10 maximal isometric contractions against a force plate, with the elbow at 90°. During two sessions, we integrated MI practice (focusing on either muscle activation or relaxation) during the inter-trial rest periods. We measured muscle performance from force plate and electromyograms of the biceps brachii and anterior deltoideus. We continuously monitored electrodermal activity (EDA) to control sympathetic nervous system activity. MI of muscle activation resulted in higher isometric force as compared to both MI of muscle relaxation and passive recovery (respectively +2.1% and +3.5%). MI practice of muscle relaxation also outperformed the control condition (+1.9%). Increased activation of the biceps brachii was recorded under both MI practice conditions compared to control. Biceps brachii activation was similar between the two MI practice conditions, but electromyography revealed a marginal trend toward greater activation of the anterior deltoideus during MI practice of muscle activation. EDA and self-reports indicated that these effects were independent from physiological arousal and motivation. These results might account for priming effects of MI practice yielding to higher muscle activation and force performance. Present findings may be of interest for applications in sports training and neurologic rehabilitation. PMID:26241339

  11. [THE INFLUENCE OF LEU-ENKEPHALIN AND MEDICAL PLANTS ON MOTOR ACTIVITY OF STOMACH IN DOGS].

    PubMed

    Vymjatnina, Z K; Prosekina, E Y; Tomova, T A

    2015-01-01

    The aim of the real research was a study influence of leu-enkephalin and extracts from the leaves of goose-grass large, of burdock of felted and root of chicory on the motor function of stomach for dogs. The study was carried out on 6 outbred dogs-males, by mass 14-17 kg, with the fistula of stomach by Basov. A leu-enkephalin ("Vector", Russia) was entered intravenously in a dose 7 mcg/kg. The corresponding plant-based preparations entered perorally during 10-14 days to beginning of experiments, on an empty stomach, in a volume a no more than 20 ml. Experiments put in a morning clock, in 16-18 hours after eating, after the careful washing of stomach. For 30 mines to the record of motive activity of stomach an animal was enter a peptide or gave a corresponding extract as water or spirit infusion. At the choice of doses of vegetable preparations came from the before obtained data about the antiulcerous action of the used plants. The conduct of peptide rendered considerable stimulant influence on motor activity of stomach, that was expressed in the increase of period of work and increase of force of reductions especially tonic. All used plants preparations rendered modulating influence on motive activity of stomach. Changes consisted in strengthening of tonic and oppressing of phase component. The most considerable decline of amount of phase reductions caused application of extract of goose-grass. Not only an amount but also force of phase reductions diminished thus. An extract from the root of chicory less considerably reduced the arnount of Phase reJuctions, but here substantially increased their force. All used herbal medicines stimulated tonic activity. Thus, peptide and all studied herbal medicines stimulated motion activity of the stomach that could cause acceleration of evacuation of food to duodenum. Such effect should be considered while choosing the medicine for correction of stomach functional activity. PMID:26931013

  12. Accurate stepping on a narrow path: mechanics, EMG, and motor cortex activity in the cat.

    PubMed

    Farrell, Brad J; Bulgakova, Margarita A; Sirota, Mikhail G; Prilutsky, Boris I; Beloozerova, Irina N

    2015-11-01

    How do cats manage to walk so graciously on top of narrow fences or windowsills high above the ground while apparently exerting little effort? In this study we investigated cat full-body mechanics and the activity of limb muscles and motor cortex during walking along a narrow 5-cm path on the ground. We tested the hypotheses that during narrow walking 1) lateral stability would be lower because of the decreased base-of-support area and 2) the motor cortex activity would increase stride-related modulation because of imposed demands on lateral stability and paw placement accuracy. We measured medio-lateral and rostro-caudal dynamic stability derived from the extrapolated center of mass position with respect to the boundaries of the support area. We found that cats were statically stable in the frontal plane during both unconstrained and narrow-path walking. During narrow-path walking, cats walked slightly slower with more adducted limbs, produced smaller lateral forces by hindlimbs, and had elevated muscle activities. Of 174 neurons recorded in cortical layer V, 87% of forelimb-related neurons (from 114) and 90% of hindlimb-related neurons (from 60) had activities during narrow-path walking distinct from unconstrained walking: more often they had a higher mean discharge rate, lower depth of stride-related modulation, and/or longer period of activation during the stride. These activity changes appeared to contribute to control of accurate paw placement in the medio-lateral direction, the width of the stride, rather than to lateral stability control, as the stability demands on narrow-path and unconstrained walking were similar. PMID:26354314

  13. Electrocorticographic activity over sensorimotor cortex and motor function in awake behaving rats

    PubMed Central

    Chen, Xiang Yang; Wolpaw, Jonathan R.

    2015-01-01

    Sensorimotor cortex exerts both short-term and long-term control over the spinal reflex pathways that serve motor behaviors. Better understanding of this control could offer new possibilities for restoring function after central nervous system trauma or disease. We examined the impact of ongoing sensorimotor cortex (SMC) activity on the largely monosynaptic pathway of the H-reflex, the electrical analog of the spinal stretch reflex. In 41 awake adult rats, we measured soleus electromyographic (EMG) activity, the soleus H-reflex, and electrocorticographic activity over the contralateral SMC while rats were producing steady-state soleus EMG activity. Principal component analysis of electrocorticographic frequency spectra before H-reflex elicitation consistently revealed three frequency bands: μβ (5–30 Hz), low γ (γ1; 40–85 Hz), and high γ (γ2; 100–200 Hz). Ongoing (i.e., background) soleus EMG amplitude correlated negatively with μβ power and positively with γ1 power. In contrast, H-reflex size correlated positively with μβ power and negatively with γ1 power, but only when background soleus EMG amplitude was included in the linear model. These results support the hypothesis that increased SMC activation (indicated by decrease in μβ power and/or increase in γ1 power) simultaneously potentiates the H-reflex by exciting spinal motoneurons and suppresses it by decreasing the efficacy of the afferent input. They may help guide the development of new rehabilitation methods and of brain-computer interfaces that use SMC activity as a substitute for lost or impaired motor outputs. PMID:25632076

  14. Meat Feeding Restricts Rapid Cold Hardening Response and Increases Thermal Activity Thresholds of Adult Blow Flies, Calliphora vicina (Diptera: Calliphoridae)

    PubMed Central

    2015-01-01

    Virtually all temperate insects survive the winter by entering a physiological state of reduced metabolic activity termed diapause. However, there is increasing evidence that climate change is disrupting the diapause response resulting in non-diapause life stages encountering periods of winter cold. This is a significant problem for adult life stages in particular, as they must remain mobile, periodically feed, and potentially initiate reproductive development at a time when resources should be diverted to enhance stress tolerance. Here we present the first evidence of protein/meat feeding restricting rapid cold hardening (RCH) ability and increasing low temperature activity thresholds. No RCH response was noted in adult female blow flies (Calliphora vicina Robineau-Desvoidy) fed a sugar, water and liver (SWL) diet, while a strong RCH response was seen in females fed a diet of sugar and water (SW) only. The RCH response in SW flies was induced at temperatures as high as 10°C, but was strongest following 3h at 0°C. The CTmin (loss of coordinated movement) and chill coma (final appendage twitch) temperature of SWL females (-0.3 ± 0.5°C and -4.9 ± 0.5°C, respectively) was significantly higher than for SW females (-3.2 ± 0.8°C and -8.5 ± 0.6°C). We confirmed this was not directly the result of altered extracellular K+, as activity thresholds of alanine-fed adults were not significantly different from SW flies. Instead we suggest the loss of cold tolerance is more likely the result of diverting resource allocation to egg development. Between 2009 and 2013 winter air temperatures in Birmingham, UK, fell below the CTmin of SW and SWL flies on 63 and 195 days, respectively, suggesting differential exposure to chill injury depending on whether adults had access to meat or not. We conclude that disruption of diapause could significantly impact on winter survival through loss of synchrony in the timing of active feeding and reproductive development with favourable

  15. From Cerebellar Activation and Connectivity to Cognition: A Review of the Quadrato Motor Training

    PubMed Central

    Ben-Soussan, Tal Dotan; Glicksohn, Joseph; Berkovich-Ohana, Aviva

    2015-01-01

    The importance of the cerebellum is increasingly recognized, not only in motor control but also in cognitive learning and function. Nevertheless, the relationship between training-induced cerebellar activation and electrophysiological and structural changes in humans has yet to be established. In the current paper, we suggest a general model tying cerebellar function to cognitive improvement, via neuronal synchronization, as well as biochemical and anatomical changes. We then suggest that sensorimotor training provides an optimal paradigm to test the proposed model and review supporting evidence of Quadrato Motor Training (QMT), a sensorimotor training aimed at increasing attention and coordination. Subsequently, we discuss the possible mechanisms through which QMT may exert its beneficial effects on cognition (e.g., increased creativity, reflectivity, and reading), focusing on cerebellar alpha activity as a possible mediating mechanism allowing cognitive improvement, molecular and anatomical changes. Using the example of QMT research, this paper emphasizes the importance of investigating whole-body sensorimotor training paradigms utilizing a multidisciplinary approach and its implications to healthy brain development. PMID:26539545

  16. From Cerebellar Activation and Connectivity to Cognition: A Review of the Quadrato Motor Training.

    PubMed

    Ben-Soussan, Tal Dotan; Glicksohn, Joseph; Berkovich-Ohana, Aviva

    2015-01-01

    The importance of the cerebellum is increasingly recognized, not only in motor control but also in cognitive learning and function. Nevertheless, the relationship between training-induced cerebellar activation and electrophysiological and structural changes in humans has yet to be established. In the current paper, we suggest a general model tying cerebellar function to cognitive improvement, via neuronal synchronization, as well as biochemical and anatomical changes. We then suggest that sensorimotor training provides an optimal paradigm to test the proposed model and review supporting evidence of Quadrato Motor Training (QMT), a sensorimotor training aimed at increasing attention and coordination. Subsequently, we discuss the possible mechanisms through which QMT may exert its beneficial effects on cognition (e.g., increased creativity, reflectivity, and reading), focusing on cerebellar alpha activity as a possible mediating mechanism allowing cognitive improvement, molecular and anatomical changes. Using the example of QMT research, this paper emphasizes the importance of investigating whole-body sensorimotor training paradigms utilizing a multidisciplinary approach and its implications to healthy brain development. PMID:26539545

  17. Dopaminergic modulation of motor neuron activity and neuromuscular function in Drosophila melanogaster.

    PubMed

    Cooper, R L; Neckameyer, W S

    1999-02-01

    Dopamine is found in both neuronal and non-neuronal tissues in the larval stage of the fruit fly, Drosophila melanogaster, and functions as a signaling molecule in the nervous system. Although dopaminergic neurons in the central nervous system (CNS) were previously thought solely to be interneurons, recent studies suggest that dopamine may also act as a neuromodulator in humoral pathways. We examined both application of dopamine on intact larval CNS-segmental preparations and isolated neuromuscular junctions (NMJs). Dopamine rapidly decreased the rhythmicity of the CNS motor activity. Application of dopamine on neuromuscular preparations of the segmental muscles 6 and 7 resulted in a dose-responsive decrease in the excitatory junction potentials (EJPs). With the use of focal, macro-patch synaptic current recordings the quantal evoked transmission showed a depression of vesicular release at concentrations of 10 microM. Higher concentrations (1 mM) produced a rapid decrement in evoked vesicular release. Dopamine did not alter the shape of the spontaneous synaptic currents, suggesting that dopamine does not alter the postsynaptic muscle fiber receptiveness to the glutaminergic motor nerve transmission. The effects are presynaptic in causing a reduction in the number of vesicles that are stimulated to be released due to neural activity. PMID:10327610

  18. Relationships between physical activity and motor skills in middle school children.

    PubMed

    Reed, Julian A; Metzker, Andrea; Phillips, D Allen

    2004-10-01

    The purpose of this study was to examine the relationships between physical activity measured as pedometer steps and performance on three motor skill tests. A secondary purpose was to determine if middle school children are meeting the recommendation for the number of daily steps. A sample (n =217) of 6th, 7th and 8th grade students participated. Each subject wore a Digi-Walker pedometer for three consecutive days. Subjects additionally recorded their pedometer steps in two 45 min.-physical education classes. There were strong significant correlations between daily steps taken by boys and girls, pedometer steps during physical education class and the AAHPERD Passing Test and the Bass Stick Balance. Similar correlations were weaker for the Side-Step Agility Test. Multivariate analysis of variance was utilized to examine variability of the three skills test by sex and year in school. Differences between students in Grades 7 and 8 on the AAHPERD Passing Test were significant. In addition, significant differences between daily pedometer steps and steps during physical education between Grades 6 and 7 were observed. Boys and girls had similar means on the AAHPERD Passing Test and Bass Stick Balance Test, but not on the Side-Step Agility Test. Scores on the three movement skills tested in this study were not strongly related to physical activity of the entire sample. Steps taken by middle school children appear not to be related to these measures of motor skills. PMID:15560336

  19. Subthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson’s disease

    PubMed Central

    Klotz, Rosa; Govindan, Rathinaswamy B.; Scholten, Marlieke; Naros, Georgios; Ramos-Murguialday, Ander; Bunjes, Friedemann; Meisner, Christoph; Plewnia, Christian; Krüger, Rejko

    2015-01-01

    Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson’s disease. Here, we set out to address the motor network activity and synchronization in Parkinson’s disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson’s disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with ‘stimulation on’ compared to ‘stimulation off’ on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With ‘stimulation on’, interhemispheric cortico

  20. Network feedback regulates motor output across a range of modulatory neuron activity.

    PubMed

    Spencer, Robert M; Blitz, Dawn M

    2016-06-01

    Modulatory projection neurons alter network neuron synaptic and intrinsic properties to elicit multiple different outputs. Sensory and other inputs elicit a range of modulatory neuron activity that is further shaped by network feedback, yet little is known regarding how the impact of network feedback on modulatory neurons regulates network output across a physiological range of modulatory neuron activity. Identified network neurons, a fully described connectome, and a well-characterized, identified modulatory projection neuron enabled us to address this issue in the crab (Cancer borealis) stomatogastric nervous system. The modulatory neuron modulatory commissural neuron 1 (MCN1) activates and modulates two networks that generate rhythms via different cellular mechanisms and at distinct frequencies. MCN1 is activated at rates of 5-35 Hz in vivo and in vitro. Additionally, network feedback elicits MCN1 activity time-locked to motor activity. We asked how network activation, rhythm speed, and neuron activity levels are regulated by the presence or absence of network feedback across a physiological range of MCN1 activity rates. There were both similarities and differences in responses of the two networks to MCN1 activity. Many parameters in both networks were sensitive to network feedback effects on MCN1 activity. However, for most parameters, MCN1 activity rate did not determine the extent to which network output was altered by the addition of network feedback. These data demonstrate that the influence of network feedback on modulatory neuron activity is an important determinant of network output and feedback can be effective in shaping network output regardless of the extent of network modulation. PMID:27030739

  1. Analysis of neural activity in human motor cortex -- Towards brain machine interface system

    NASA Astrophysics Data System (ADS)

    Secundo, Lavi

    , the correlation of ECoG activity to kinematic parameters of arm movement is context-dependent, an important constraint to consider in future development of BMI systems. The third chapter delves into a fundamental organizational principle of the primate motor system---cortical control of contralateral limb movements. However, ipsilateral motor areas also appear to play a role in the control of ipsilateral limb movements. Several studies in monkeys have shown that individual neurons in ipsilateral primary motor cortex (M1) may represent, on average, the direction of movements of the ipsilateral arm. Given the increasing body of evidence demonstrating that neural ensembles can reliably represent information with a high temporal resolution, here we characterize the distributed neural representation of ipsilateral upper limb kinematics in both monkey and man. In two macaque monkeys trained to perform center-out reaching movements, we found that the ensemble spiking activity in M1 could continuously represent ipsilateral limb position. We also recorded cortical field potentials from three human subjects and also consistently found evidence of a neural representation for ipsilateral movement parameters. Together, our results demonstrate the presence of a high-fidelity neural representation for ipsilateral movement and illustrates that it can be successfully incorporated into a brain-machine interface.

  2. Neural co-activation as a yardstick of implicit motor learning and the propensity for conscious control of movement.

    PubMed

    Zhu, F F; Poolton, J M; Wilson, M R; Maxwell, J P; Masters, R S W

    2011-04-01

    Two studies examined EEG co-activation (coherence) between the verbal-analytical (T3) and motor planning (Fz) regions during a golf putting task. In Study 1, participants with a strong propensity to consciously monitor and control their movements, determined psychometrically by high scores on a movement specific Reinvestment Scale, displayed more alpha2 T3-Fz co-activation than participants with a weak propensity. In Study 2, participants who practiced a golf putting task implicitly (via an errorless learning protocol) displayed less alpha2 T3-Fz co-activation than those who practiced explicitly (by errorful learning). In addition, explicit but not implicit motor learners displayed more T3-Fz co-activation during golf putting under pressure, implying that verbal-analytical processing of putting movements increased under pressure. These findings provide neuropsychological evidence that supports claims that implicit motor learning can be used to limit movement specific reinvestment. PMID:21315795

  3. Influence of morphine on the activity of low-threshold visceral mechanoreceptors in cats with acute pericarditis.

    PubMed

    Bałkowiec, A; Kukuła, K; Szulczyk, P

    1994-11-01

    The purpose of this investigation was to test whether morphine (morphinum hydrochloricum) applied to the receptive field of the thoracic visceral afferent fibres modifies their activity. Experiments were performed on chloralose-anaesthetised cats, paralysed and artificially ventilated, in a state of pericarditis that was induced by intrapericardial injection of lambda-carrageenan and kaolin. Resulting acute inflammation was proven histopathologically and documented electrocardiographically. Single afferent fibres with receptive fields in thoracic viscera were dissected from thoracic sympathetic chain (19 fibres), as well as the vagus nerve (9 fibres). All tested fibres transmitted sensory information from the low-threshold mechanoreceptors. As a final result, it was found that morphine (0.001-1.0 mg/ml) when applied locally activates, depending on the dose, afferent fibres as follows: 12 sympathetic afferents (out of 12 tested), and 7 vagal afferents (out of 9 tested). In examining the specificity of morphine action, the preliminary local application of naloxone (1.0 mg/ml) just before morphine, blocked all excitatory responses. The excitatory response was present whether the receptive field was located in the inflammatory area, or outside it, in group III or IV fibres. PMID:7892023

  4. Effects of physical activity on executive function and motor performance in children with ADHD.

    PubMed

    Ziereis, Susanne; Jansen, Petra

    2015-03-01

    Children with Attention-Deficit/Hyperactivity Disorder (ADHD) often show major deficits in motor and cognitive abilities. Pharmacological treatment is commonly used to reduce ADHD symptoms. However, non-pharmacologic treatment methods would be preferred by parents, children and psychiatrists. Physical activity (PA) has been demonstrated to improve cognitive functioning in healthy populations. It can be hypothesized that there are similar beneficial effects in children with ADHD, however, very little is known about this issue. The purpose of the present study was to determine whether PA improves cognitive performance in children with ADHD. A total of 43 children with ADHD (32 boys and 11 girls) aged between seven and 12 years took part in the study. To investigate whether potential effects on executive functioning depend on the kind of PA, two different 12-week training programs were implemented. The study-design consisted of two experimental groups (EG1, n=13; EG2, n=14) and a wait-list control group (CG, n=16). Participants in EG1 took part in a training which focused on the abilities ball handling, balance and manual dexterity. Participants in EG2 group were trained in sports without a specific focus. The children in the CG group received no intervention. Participants completed assessments of working memory (WM) and motor performance before, immediately after the first training week and one week after the last session. After the 12-week intervention period, several measures of the EG1 and EG2s significantly improved over time. Furthermore, between group comparisons demonstrated significant improvements in both EG1 and EG2 compared to the CG in variables assessing WM performance and motor performance. These findings support the hypothesis that long-term PA has a positive effect on executive functions of children with ADHD, regardless of the specificity of the PA. The outcomes indicated that regular PA can be used as a complementary or alternative non

  5. Activity-dependent competition regulates motor neuron axon pathfinding via PlexinA3

    PubMed Central

    Plazas, Paola V.; Nicol, Xavier; Spitzer, Nicholas C.

    2013-01-01

    The role of electrical activity in axon guidance has been extensively studied in vitro. To better understand its role in the intact nervous system, we imaged intracellular Ca2+ in zebrafish primary motor neurons (PMN) during axon pathfinding in vivo. We found that PMN generate specific patterns of Ca2+ spikes at different developmental stages. Spikes arose in the distal axon of PMN and were propagated to the cell body. Suppression of Ca2+ spiking activity in single PMN led to stereotyped errors, but silencing all electrical activity had no effect on axon guidance, indicating that an activity-based competition rule regulates this process. This competition was not mediated by synaptic transmission. Combination of PlexinA3 knockdown with suppression of Ca2+ activity in single PMN produced a synergistic increase in the incidence of pathfinding errors. However, expression of PlexinA3 transcripts was not regulated by activity. Our results provide an in vivo demonstration of the intersection of spontaneous electrical activity with the PlexinA3 guidance molecule receptor in regulation of axon pathfinding. PMID:23302694

  6. Complement activity is associated with disease severity in multifocal motor neuropathy

    PubMed Central

    Vlam, Lotte; Cats, Elisabeth A.; Harschnitz, Oliver; Jansen, Marc D.; Piepers, Sanne; Veldink, Jan Herman; Franssen, Hessel; Stork, Abraham C.J.; Heezius, Erik; Rooijakkers, Suzan H.M.; Herpers, Bjorn L.; van Strijp, Jos A.; van den Berg, Leonard H.

    2015-01-01

    Objective: To investigate whether high innate activity of the classical and lectin pathways of complement is associated with multifocal motor neuropathy (MMN) and whether levels of innate complement activity or the potential of anti-GM1 antibodies to activate the complement system correlate with disease severity. Methods: We performed a case-control study including 79 patients with MMN and 79 matched healthy controls. Muscle weakness was documented with Medical Research Council scale sum score and axonal loss with nerve conduction studies. Activity of the classical and lectin pathways of complement was assessed by ELISA. We also determined serum mannose-binding lectin (MBL) concentrations and polymorphisms in the MBL gene (MBL2) and quantified complement-activating properties of anti-GM1 IgM antibodies by ELISA. Results: Activity of the classical and lectin pathways, MBL2 genotypes, and serum MBL concentrations did not differ between patients and controls. Complement activation by anti-GM1 IgM antibodies was exclusively mediated through the classical pathway and correlated with antibody titers (p < 0.001). Logistic regression analysis showed that both high innate activity of the classical pathway of complement and high complement-activating capacity of anti-GM1 IgM antibodies were significantly associated with more severe muscle weakness and axonal loss. Conclusion: High innate activity of the classical pathway of complement and efficient complement-activating properties of anti-GM1 IgM antibodies are determinants of disease severity in patients with MMN. These findings underline the importance of anti-GM1 antibody–mediated complement activation in the pathogenesis and clinical course of MMN. PMID:26161430

  7. Treating apraxia of speech with an implicit protocol that activates speech motor areas via inner speech

    PubMed Central

    Farias, Dana; Davis, Christine Herrick; Wilson, Stephen M

    2014-01-01

    Background Treatments of apraxia of speech (AOS) have traditionally relied on overt practice. One alternative to this method is implicit phoneme manipulation which was derived from early models on inner speech. Implicit phoneme manipulation requires the participant to covertly move and combine phonemes to form a new word. This process engages a system of self-monitoring which is referred to as fully conscious inner speech. Aims The present study aims to advance the understanding and validity of a new treatment for AOS, implicit phoneme manipulation. Tasks were designed to answer the following questions. 1. Would the practice of implicit phoneme manipulation improve the overt production of complex consonant blends in words? 2. Would this improvement generalize to untrained complex and simpler consonant blends in words? 3. Would these treatment tasks activate regions known to support motor planning and programming as verified by fMRI? Method & Procedures The participant was asked to covertly manipulate phonemes to create a new word and to associate this newly formed word to a target picture among 4 phonologically-related choices. To avoid overt practice, probes were collected only after each block of training was completed. Probe sessions assessed the effects of implicit practice on the overt production of simple and complex consonant blends in words. An imaging protocol compared semantic baseline tasks to treatment tasks to verify that implicit phoneme manipulation activated brain regions of interest. Outcomes & Results Behavioral: Response to implicit training of complex consonant blends resulted in improvements which were maintained 6 weeks after treatment. Further, this treatment generalized to simpler consonant blends in words. Imaging: Functional imaging during implicit phoneme manipulation showed significant activation in brain regions responsible for phonological processing when compared to the baseline semantic task. Conclusions Implicit phoneme manipulation

  8. Decreased Connectivity and Cerebellar Activity in Autism during Motor Task Performance

    ERIC Educational Resources Information Center

    Mostofsky, Stewart H.; Powell, Stephanie K.; Simmonds, Daniel J.; Goldberg, Melissa C.; Caffo, Brian; Pekar, James J.

    2009-01-01

    Although motor deficits are common in autism, the neural correlates underlying the disruption of even basic motor execution are unknown. Motor deficits may be some of the earliest identifiable signs of abnormal development and increased understanding of their neural underpinnings may provide insight into autism-associated differences in parallel…

  9. Thresholds of arsenic toxicity to Eisenia fetida in field-collected agricultural soils exposed to copper mining activities in Chile.

    PubMed

    Bustos, Víctor; Mondaca, Pedro; Verdejo, José; Sauvé, Sébastien; Gaete, Hernán; Celis-Diez, Juan L; Neaman, Alexander

    2015-12-01

    Several previous studies highlighted the importance of using field-collected soils-and not artificially-contaminated soils-for ecotoxicity tests. However, the use of field-collected soils presents several difficulties for interpretation of results, due to the presence of various contaminants and unavoidable differences in the physicochemical properties of the tested soils. The objective of this study was to estimate thresholds of metal toxicity in topsoils of 24 agricultural areas historically contaminated by mining activities in Chile. We performed standardized earthworm reproduction tests (OECD 222 and ISO 11268-2) with Eisenia fetida. Total soil concentrations of Cu, As, Zn, and Pb were in the ranges of 82-1295 mg kg(-1), 7-41 mg kg(-1), 86-345 mg kg(-1), and 25-97 mg kg(-1), respectively. In order to differentiate between the effects of different metals, we used regression analysis between soil metal concentrations and earthworm responses, as well as between metal concentrations in earthworm tissues and earthworm responses. Based on regression analysis, we concluded that As was a metal of prime concern for Eisenia fetida in soils affected by Cu mining activities, while Cu exhibited a secondary effect. In contrast, the effects of Zn and Pb were not significant. Soil electrical conductivity was another significant contributor to reproduction toxicity in the studied soils, forcing its integration in the interpretation of the results. By using soils with electrical conductivity ≤ 0.29 dS m(-1) (which corresponds to EC50 of salt toxicity to Eisenia fetida), it was possible to isolate the effect of soil salinity on earthworm reproduction. Despite the confounding effects of Cu, it was possible to determine EC10, EC25 and EC50 values for total soil As at 8 mg kg(-1), 14 mg kg(-1) and 22 mg kg(-1), respectively, for the response of the cocoon production. However, it was not possible to determine these threshold values for juvenile production. Likewise, we were able to

  10. Systematic review of the relationship between habitual physical activity and motor capacity in children with cerebral palsy.

    PubMed

    Keawutan, Piyapa; Bell, Kristie; Davies, Peter S W; Boyd, Roslyn N

    2014-06-01

    Habitual physical activity (HPA) has many benefits for general health. Motor capacity in children with cerebral palsy (CP) can impact on their HPA. This study aimed to systematically review the available literature on the relationship between HPA and motor capacity in children with CP aged 3-12 years for all gross motor functional abilities (GMFCS I-V) compared to typically developing children. Five electronic databases (Pubmed, Cochrane, Embase, Cinahl and Web of Science from 1989 to November, 2013) were searched using keywords "children with cerebral palsy", "physical activity", "motor capacity" and "motor function" including their synonyms and MesH terms. Studies were included if they (i) were conducted in children with CP aged between 3 and 12 years, (ii) assessed HPA or time spent sedentary, (iii) assessed motor capacity in order to evaluate the relationship between HPA and motor capacity. All articles retrieved were reviewed by two independent reviewers and discussed until they reached consensus. Study quality of reporting was evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria. Search results identified 864 articles but after review of the title and abstract only 21 articles warranted closer consideration. Ten articles met the strict inclusion criteria as nine articles did not assess HPA and two were conference abstracts. Study quality assessment (STROBE) found nine articles were good quality (≥ 60%) and one was poor quality (55.9%). Participants were mean age 8.4 (SD=2.1) years (range 2-17 years) and included children at all GMFCS levels (3 studies), while seven studies only recruited GMFCS level I-III. HPA measurements were either subjective (Activity Scale for Kids, Dutch Questionnaire of Participation in physical activity and assessment of participation in physical education at school and regular physical activity in leisure time) or objective (StepWatch(®) and ActiGraph(®)7164). Nine studies

  11. Motor Ability and Weight Status Are Determinants of Out-of-School Activity Participation for Children with Developmental Coordination Disorder

    ERIC Educational Resources Information Center

    Fong, Shirley S. M.; Lee, Velma Y. L.; Chan, Nerita N. C.; Chan, Rachel S. H.; Chak, Wai-Kwong; Pang, Marco Y. C.

    2011-01-01

    According to the International Classification of Functioning, Disability and Health model endorsed by the World Health Organization, participation in everyday activities is integral to normal child development. However, little is known about the influence of motor ability and weight status on physical activity participation in children with…

  12. Influence of respiratory motor neurone activity on human autonomic and haemodynamic rhythms

    NASA Technical Reports Server (NTRS)

    Gonschorek, A. S.; Lu, L. L.; Halliwill, J. R.; Beightol, L. A.; Taylor, J. A.; Painter, J. A.; Warzel, H.; Eckberg, D. L.

    2001-01-01

    Although humans hold great advantages over other species as subjects for biomedical research, they also bring major disadvantages. One is that among the many rhythmic physiological signals that can be recorded, there is no sure way to know which individual change precedes another, or which change represents cause and which represents effect. In an attempt to deal with the inherent complexity of research conducted in intact human subjects, we developed and used a structural equation model to analyse responses of healthy young men to pharmacological changes of arterial pressure and graded inspiratory resistance, before and after vagomimetic atropine. Our model yielded a good fit of the experimental data, with a system weighted R2 of 0.77, and suggested that our treatments exerted both direct and indirect influences on the variables we measured. Thus, infusions of nitroprusside and phenylephrine exerted all of their direct effects by lowering and raising arterial pressure; the changes of R-R intervals, respiratory sinus arrhythmia and arterial pressure fluctuations that these drugs provoked, were indirect consequences of arterial pressure changes. The only direct effect of increased inspiratory resistance was augmentation of arterial pressure fluctuations. These results may provide a new way to disentangle and understand responses of intact human subjects to experimental forcings. The principal new insight we derived from our modelling is that respiratory gating of vagal-cardiac motor neurone firing is nearly maximal at usual levels of arterial pressure and inspiratory motor neurone activity.

  13. Comparison of the threshold of thermal-induced mode instabilities in polarization-maintaining and non-polarization-maintaining active fibers

    NASA Astrophysics Data System (ADS)

    Tao, Rumao; Ma, Pengfei; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2016-06-01

    We present an investigation on the threshold of thermal-induced mode instability (MI) in ytterbium-doped polarization-maintaining and non-polarization-maintaining active fibers. By taking both electric fields along the two principal axes into consideration, we extend a previous steady-state theoretical model to analyze the polarization effect on MI. Based on the model, we analyzed whether maintaining the fiber’s polarization direction has an effect on the MI threshold, which showed that, for practical high power fiber laser systems, the MI threshold is nearly the same for polarization-maintaining and non-polarization-maintaining active fibers. Experimental validation of the theoretical analysis is presented with experimental results agreeing with the theoretical results, in which polarization-maintained and non-polarization-maintained fiber lasers with similar core/inner cladding diameters are employed.

  14. Mutation in E1, the Ubiquitin Activating Enzyme, Reduces Drosophila Lifespan and Results in Motor Impairment

    PubMed Central

    Liu, Hsiu-Yu; Pfleger, Cathie M.

    2013-01-01

    Neurodegenerative diseases cause tremendous suffering for those afflicted and their families. Many of these diseases involve accumulation of mis-folded or aggregated proteins thought to play a causal role in disease pathology. Ubiquitinated proteins are often found in these protein aggregates, and the aggregates themselves have been shown to inhibit the activity of the proteasome. These and other alterations in the Ubiquitin Pathway observed in neurodegenerative diseases have led to the question of whether impairment of the Ubiquitin Pathway on its own can increase mortality or if ongoing neurodegeneration alters Ubiquitin Pathway function as a side-effect. To address the role of the Ubiquitin Pathway in vivo, we studied loss-of-function mutations in the Drosophila Ubiquitin Activating Enzyme, Uba1 or E1, the most upstream enzyme in the Ubiquitin Pathway. Loss of only one functional copy of E1 caused a significant reduction in adult lifespan. Rare homozygous hypomorphic E1 mutants reached adulthood. These mutants exhibited further reduced lifespan and showed inappropriate Ras activation in the brain. Removing just one functional copy of Ras restored the lifespan of heterozygous E1 mutants to that of wild-type flies and increased the survival of homozygous E1 mutants. E1 homozygous mutants also showed severe motor impairment. Our findings suggest that processes that impair the Ubiquitin Pathway are sufficient to cause early mortality. Reduced lifespan and motor impairment are seen in the human disease X-linked Infantile Spinal Muscular Atrophy, which is associated with mutation in human E1 warranting further analysis of these mutants as a potential animal model for study of this disease. PMID:23382794

  15. Functional observational battery and motor activity in rats after single administration of two NHE 1 inhibitors

    SciTech Connect

    Huebler, Nicole; Gottschling, Barbara . E-mail: barbara.gottschling@merck.de; Jacobs, Maren; Landenberg, Friedrich von; Hewicker-Trautwein, Marion

    2005-11-01

    Two tests, a functional observational battery (FOB) and measurement of motor activity, have been used to screen the two NHE inhibitors EMD 96785 and EMD 125021 for neurobehavioral effects. These two NHE inhibitors, which exhibit a marked selectivity for the NHE 1 isoform, are under development in the research laboratories of Merck KGaA. NHE inhibitors are developed for the treatment of acute myocardial infarction and chronic heart failure. In prior studies with EMD 96785 and EMD 125021, clinical symptoms, such as uncoordinated movements and weakness of the hindlimbs, were detected in rats. The aim of this study was the evaluation of clinical findings in more detail using a FOB and measurement of motor activity in 96 female rats. The time course and reversibility of the adverse effects were investigated. The animals were treated with EMD 96785 or EMD 125021 by intravenous injection at a single dose of 100 mg/kg and four different time points (2 h, 1 day, 7 days and 21 days after treatment) were chosen for the clinical examination. This neurobehavioral test battery clearly detected neurological activity and defined time-course characteristics after treatment with EMD 96785 or EMD 125021. The various clinical parameters were grouped into functional-related domains and most alterations were seen in the domains of central nervous system and neuromuscular system. The most prominent clinical findings were seen with the pharmacologically more potent NHE inhibitor EMD 125021 when compared to EMD 96785. The clinical symptoms were proven to be reversible by 7 days after the single treatment for both compounds.

  16. Automated ambulatory assessment of cognitive performance, environmental conditions, and motor activity during military operations

    NASA Astrophysics Data System (ADS)

    Lieberman, Harris R.; Kramer, F. Matthew; Montain, Scott J.; Niro, Philip; Young, Andrew J.

    2005-05-01

    Until recently scientists had limited opportunities to study human cognitive performance in non-laboratory, fully ambulatory situations. Recently, advances in technology have made it possible to extend behavioral assessment to the field environment. One of the first devices to measure human behavior in the field was the wrist-worn actigraph. This device, now widely employed, can acquire minute-by-minute information on an individual"s level of motor activity. Actigraphs can, with reasonable accuracy, distinguish sleep from waking, the most critical and basic aspect of human behavior. However, rapid technologic advances have provided the opportunity to collect much more information from fully ambulatory humans. Our laboratory has developed a series of wrist-worn devices, which are not much larger then a watch, which can assess simple and choice reaction time, vigilance and memory. In addition, the devices can concurrently assess motor activity with much greater temporal resolution then the standard actigraph. Furthermore, they continuously monitor multiple environmental variables including temperature, humidity, sound and light. We have employed these monitors during training and simulated military operations to collect information that would typically be unavailable under such circumstances. In this paper we will describe various versions of the vigilance monitor and how each successive version extended the capabilities of the device. Samples of data from several studies are presented, included studies conducted in harsh field environments during simulated infantry assaults, a Marine Corps Officer training course and mechanized infantry (Stryker) operations. The monitors have been useful for documenting environmental conditions experienced by wearers, studying patterns of sleep and activity and examining the effects of nutritional manipulations on warfighter performance.

  17. Radiation Treatment Planning Using Positron Emission and Computed Tomography for Lung and Pharyngeal Cancers: A Multiple-Threshold Method for [{sup 18}F]Fluoro-2-Deoxyglucose Activity

    SciTech Connect

    Okubo, Mitsuru; Nishimura, Yasumasa; Nakamatsu, Kiyoshi; Okumura, Masahiko R.T.; Shibata, Toru; Kanamori, Shuichi; Hanaoka, Kouhei R.T.; Hosono, Makoto

    2010-06-01

    Purpose: Clinical applicability of a multiple-threshold method for [{sup 18}F]fluoro-2-deoxyglucose (FDG) activity in radiation treatment planning was evaluated. Methods and Materials: A total of 32 patients who underwent positron emission and computed tomography (PET/CT) simulation were included; 18 patients had lung cancer, and 14 patients had pharyngeal cancer. For tumors of <=2 cm, 2 to 5 cm, and >5 cm, thresholds were defined as 2.5 standardized uptake value (SUV), 35%, and 20% of the maximum FDG activity, respectively. The cervical and mediastinal lymph nodes with the shortest axial diameter of >=10 mm were considered to be metastatic on CT (LNCT). The retropharyngeal lymph nodes with the shortest axial diameter of >=5 mm on CT and MRI were also defined as metastatic. Lymph nodes showing maximum FDG activity greater than the adopted thresholds for radiation therapy planning were designated LNPET-RTP, and lymph nodes with a maximum FDG activity of >=2.5 SUV were regarded as malignant and were designated LNPET-2.5 SUV. Results: The sizes of gross tumor volumes on PET (GTVPET) with the adopted thresholds in the axial plane were visually well fitted to those of GTV on CT (GTVCT). However, the volumes of GTVPET were larger than those of GTVCT, with significant differences (p < 0.0001) for lung cancer, due to respiratory motion. For lung cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 29, 28, and 34, respectively. For pharyngeal cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 14, 9, and 15, respectively. Conclusions: Our multiple thresholds were applicable for delineating the primary target on PET/CT simulation. However, these thresholds were inaccurate for depicting malignant lymph nodes.

  18. GABAA receptor antagonism at the hypoglossal motor nucleus increases genioglossus muscle activity in NREM but not REM sleep.

    PubMed

    Morrison, Janna L; Sood, Sandeep; Liu, Hattie; Park, Eileen; Nolan, Philip; Horner, Richard L

    2003-04-15

    The pharyngeal muscles, such as the genioglossus (GG) muscle of the tongue, are important for effective lung ventilation since they maintain an open airspace. Rapid-eye-movement (REM) sleep, however, recruits powerful neural mechanisms that can abolish GG activity, even during strong reflex respiratory stimulation by elevated CO2. In vitro studies have demonstrated the presence of GABAA receptors on hypoglossal motoneurons, and these and other data have led to the speculation that GABAA mechanisms may contribute to the suppression of hypoglossal motor outflow to the GG muscle in REM sleep. We have developed an animal model that allows us to chronically manipulate neurotransmission at the hypoglossal motor nucleus using microdialysis across natural sleep-wake states in rats. The present study tests the hypothesis that microdialysis perfusion of the GABAA receptor antagonist bicuculline into the hypoglossal motor nucleus will prevent the suppression of GG muscle activity in REM sleep during both room-air and CO2-stimulated breathing. Ten rats were implanted with electroencephalogram and neck muscle electrodes to record sleep-wake states, and GG and diaphragm electrodes for respiratory muscle recording. Microdialysis probes were implanted into the hypoglossal motor nucleus for perfusion of artificial cerebrospinal fluid (ACSF) or 100 microM bicuculline during room-air and CO2-stimulated breathing (7 % inspired CO2). GABAA receptor antagonism at the hypoglossal motor nucleus increased respiratory-related GG activity during both room-air (P = 0.01) and CO2-stimulated breathing (P = 0.007), indicating a background inhibitory GABA tone. However, the effects of bicuculline on GG activity depended on the prevailing sleep-wake state (P < 0.005), with bicuculline increasing GG activity in non-REM (NREM) sleep and wakefulness both in room air and hypercapnia (P < 0.01), but GG activity was effectively abolished in those REM periods without phasic twitches in the GG muscle

  19. The effect of fast and slow motor unit activation on whole-muscle mechanical performance: the size principle may not pose a mechanical paradox

    PubMed Central

    Holt, N. C.; Wakeling, J. M.; Biewener, A. A.

    2014-01-01

    The output of skeletal muscle can be varied by selectively recruiting different motor units. However, our knowledge of muscle function is largely derived from muscle in which all motor units are activated. This discrepancy may limit our understanding of in vivo muscle function. Hence, this study aimed to characterize the mechanical properties of muscle with different motor unit activation. We determined the isometric properties and isotonic force–velocity relationship of rat plantaris muscles in situ with all of the muscle active, 30% of the muscle containing predominately slower motor units active or 20% of the muscle containing predominately faster motor units active. There was a significant effect of active motor unit type on isometric force rise time (p < 0.001) and the force–velocity relationship (p < 0.001). Surprisingly, force rise time was longer and maximum shortening velocity higher when all motor units were active than when either fast or slow motor units were selectively activated. We propose this is due to the greater relative effects of factors such as series compliance and muscle resistance to shortening during sub-maximal contractions. The findings presented here suggest that recruitment according to the size principle, where slow motor units are activated first and faster ones recruited as demand increases, may not pose a mechanical paradox, as has been previously suggested. PMID:24695429

  20. Cocaine Increases Dopaminergic Neuron and Motor Activity via Midbrain α1 Adrenergic Signaling

    PubMed Central

    Goertz, Richard Brandon; Wanat, Matthew J; Gomez, Jorge A; Brown, Zeliene J; Phillips, Paul EM; Paladini, Carlos A

    2015-01-01

    Cocaine reinforcement is mediated by increased extracellular dopamine levels in the forebrain. This neurochemical effect was thought to require inhibition of dopamine reuptake, but cocaine is still reinforcing even in the absence of the dopamine transporter. Here, we demonstrate that the rapid elevation in dopamine levels and motor activity elicited by cocaine involves α1 receptor activation within the ventral midbrain. Activation of α1 receptors increases dopaminergic neuron burst firing by decreasing the calcium-activated potassium channel current (SK), as well as elevates dopaminergic neuron pacemaker firing through modulation of both SK and the hyperpolarization-activated cation currents (Ih). Furthermore, we found that cocaine increases both the pacemaker and burst-firing frequency of rat ventral-midbrain dopaminergic neurons through an α1 adrenergic receptor-dependent mechanism within the ventral tegmental area and substantia nigra pars compacta. These results demonstrate the mechanism underlying the critical role of α1 adrenergic receptors in the regulation of dopamine neurotransmission and behavior by cocaine. PMID:25374094

  1. Cortico-cortical activity between the primary and supplementary motor cortex: An intraoperative near-infrared spectroscopy study

    PubMed Central

    Fukuda, Masafumi; Takao, Tetsuro; Hiraishi, Tetsuya; Aoki, Hiroshi; Ogura, Ryosuke; Sato, Yosuke; Fujii, Yukihiko

    2015-01-01

    Background: The supplementary motor area (SMA) makes multiple reciprocal connections to many areas of the cerebral cortices, such as the primary motor cortex (PMC), anterior cingulate cortex, and various regions in the parietal somatosensory cortex. In patients with SMA seizures, epileptic discharges from the SMA rapidly propagate to the PMC. We sought to determine whether near-infrared spectroscopy (NIRS) is able to intraoperatively display hemodynamic changes in epileptic network activities between the SMA and the PMC. Case Descriptions: In a 60-year-old male with SMA seizures, we intraoperatively delivered a 500 Hz, 5-train stimulation to the medial cortical surface and measured the resulting hemodynamic changes in the PMC by calculating the oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) concentration changes during stimulation. No hemodynamic changes in the lateral cortex were observed during stimulation of the medial surface corresponding to the foot motor areas. In contrast, both HbO2 and HbR increased in the lateral cortex corresponding to the hand motor areas when the seizure onset zone was stimulated. In the premotor cortex and the lateral cortex corresponding to the trunk motor areas, hemodynamic changes showed a pattern of increased HbO2 with decreased HbR. Conclusions: This is the first reported study using intraoperative NIRS to characterize the epileptic network activities between the SMA and PMC. Our intraoperative NIRS procedure may thus be useful in monitoring the activities of cortico-cortical neural pathways such as the language system. PMID:25883836

  2. Force Feedback Controls Motor Activity and Mechanical Properties of Self-Assembling Branched Actin Networks.

    PubMed

    Bieling, Peter; Li, Tai-De; Weichsel, Julian; McGorty, Ryan; Jreij, Pamela; Huang, Bo; Fletcher, Daniel A; Mullins, R Dyche

    2016-01-14

    Branched actin networks--created by the Arp2/3 complex, capping protein, and a nucleation promoting factor--generate and transmit forces required for many cellular processes, but their response to force is poorly understood. To address this, we assembled branched actin networks in vitro from purified components and used simultaneous fluorescence and atomic force microscopy to quantify their molecular composition and material properties under various forces. Remarkably, mechanical loading of these self-assembling materials increases their density, power, and efficiency. Microscopically, increased density reflects increased filament number and altered geometry but no change in average length. Macroscopically, increased density enhances network stiffness and resistance to mechanical failure beyond those of isotropic actin networks. These effects endow branched actin networks with memory of their mechanical history that shapes their material properties and motor activity. This work reveals intrinsic force feedback mechanisms by which mechanical resistance makes self-assembling actin networks stiffer, stronger, and more powerful. PMID:26771487

  3. Switching strategies: a dolphin's use of passive and active acoustics to imitate motor actions.

    PubMed

    Jaakkola, Kelly; Guarino, Emily; Rodriguez, Mandy; Hecksher, Jane

    2013-09-01

    Scientists have long debated the extent to which animals can imitate. Observations of bottlenose dolphins suggest a sophisticated capacity for social imitation, but little is known about the nature of these abilities. Here, we explore the behavioral mechanisms underlying a dolphin's ability to copy motor actions while blindfolded (i.e., wearing eyecups). When a dolphin was asked to imitate a dolphin, a human, and then another dolphin blindfolded, his accuracy remained relatively consistent across models. However, his blindfolded echolocation dramatically increased when copying a human as compared to other dolphins, suggesting he actively switched between strategies: recognizing behaviors via characteristic sounds when possible, but via echolocation for the more novel sounding behaviors of the human. Such flexibility in changing perceptual routes demonstrates that the dolphin's imitation was not automatically elicited, but rather results from an intentional, problem-solving approach to imitation. PMID:23389771

  4. Mitochondrial alarmins released by degenerating motor axon terminals activate perisynaptic Schwann cells

    PubMed Central

    Duregotti, Elisa; Negro, Samuele; Scorzeto, Michele; Zornetta, Irene; Dickinson, Bryan C.; Chang, Christopher J.; Montecucco, Cesare; Rigoni, Michela

    2015-01-01

    An acute and highly reproducible motor axon terminal degeneration followed by complete regeneration is induced by some animal presynaptic neurotoxins, representing an appropriate and controlled system to dissect the molecular mechanisms underlying degeneration and regeneration of peripheral nerve terminals. We have previously shown that nerve terminals exposed to spider or snake presynaptic neurotoxins degenerate as a result of calcium overload and mitochondrial failure. Here we show that toxin-treated primary neurons release signaling molecules derived from mitochondria: hydrogen peroxide, mitochondrial DNA, and cytochrome c. These molecules activate isolated primary Schwann cells, Schwann cells cocultured with neurons and at neuromuscular junction in vivo through the MAPK pathway. We propose that this inter- and intracellular signaling is involved in triggering the regeneration of peripheral nerve terminals affected by other forms of neurodegenerative diseases. PMID:25605902

  5. Activation of the motor protein upon attachment: Anchors weigh in on cytoplasmic dynein regulation.

    PubMed

    Ananthanarayanan, Vaishnavi

    2016-06-01

    Cytoplasmic dynein is the major minus-end-directed motor protein in eukaryotes, and has functions ranging from organelle and vesicle transport to spindle positioning and orientation. The mode of regulation of dynein in the cell remains elusive, but a tantalising possibility is that dynein is maintained in an inhibited, non-motile state until bound to cargo. In vivo, stable attachment of dynein to the cell membrane via anchor proteins enables dynein to produce force by pulling on microtubules and serves to organise the nuclear material. Anchor proteins of dynein assume diverse structures and functions and differ in their interaction with the membrane. In yeast, the anchor protein has come to the fore as one of the key mediators of dynein activity. In other systems, much is yet to be discovered about the anchors, but future work in this area will prove invaluable in understanding dynein regulation in the cell. PMID:27143631

  6. The Impact of Physical Activity on Non-Motor Symptoms in Parkinson’s Disease: A Systematic Review

    PubMed Central

    Cusso, Melanie E.; Donald, Kenneth J.; Khoo, Tien K.

    2016-01-01

    Parkinson’s disease (PD) is a neurological disorder that is associated with both motor and non-motor symptoms (NMS). The management of PD is primarily via pharmaceutical treatment; however, non-pharmaceutical interventions have become increasingly recognized in the management of motor and NMS. In this review, the efficacy of physical activity, including physiotherapy and occupational therapy, as an intervention in NMS will be assessed. The papers were extracted between the 20th and 22nd of June 2016 from PubMed, Web of Science, Medline, Ovid, SportsDiscuss, and Scopus using the MeSH search terms “Parkinson’s,” “Parkinson,” and “Parkinsonism” in conjunction with “exercise,” “physical activity,” “physiotherapy,” “occupational therapy,” “physical therapy,” “rehabilitation,” “dance,” and “martial arts.” Twenty studies matched inclusion criteria of having 10 or more participants with diagnosed idiopathic PD participating in the intervention as well as having to evaluate the effects of physical activity on NMS in PD as controlled, randomized intervention studies. The outcomes of interest were NMS, including depression, cognition, fatigue, apathy, anxiety, and sleep. Risk of bias in the studies was evaluated using the Cochrane Collaboration’s tool for assessing risk of bias. Comparability of the various intervention methods, however, was challenging due to demographic variability and methodological differences. Nevertheless, physical activity can positively impact the global NMS burden including depression, apathy, fatigue, day time sleepiness, sleep, and cognition, thus supporting its therapeutic potential in neurodegenerative conditions such as PD. It is recommended that further adequately powered studies are conducted to assess the therapeutic role of physical activity on both motor and non-motor aspects of PD. These studies should be optimally designed to assess non-motor elements of disease using instruments validated

  7. GIRK Channels Modulate Opioid-Induced Motor Activity in a Cell Type- and Subunit-Dependent Manner

    PubMed Central

    Kotecki, Lydia; Hearing, Matthew; McCall, Nora M.; Marron Fernandez de Velasco, Ezequiel; Pravetoni, Marco; Arora, Devinder; Victoria, Nicole C.; Munoz, Michaelanne B.; Xia, Zhilian; Slesinger, Paul A.; Weaver, C. David

    2015-01-01

    G-protein-gated inwardly rectifying K+ (GIRK/Kir3) channel activation underlies key physiological effects of opioids, including analgesia and dependence. GIRK channel activation has also been implicated in the opioid-induced inhibition of midbrain GABA neurons and consequent disinhibition of dopamine (DA) neurons in the ventral tegmental area (VTA). Drug-induced disinhibition of VTA DA neurons has been linked to reward-related behaviors and underlies opioid-induced motor activation. Here, we demonstrate that mouse VTA GABA neurons express a GIRK channel formed by GIRK1 and GIRK2 subunits. Nevertheless, neither constitutive genetic ablation of Girk1 or Girk2, nor the selective ablation of GIRK channels in GABA neurons, diminished morphine-induced motor activity in mice. Moreover, direct activation of GIRK channels in midbrain GABA neurons did not enhance motor activity. In contrast, genetic manipulations that selectively enhanced or suppressed GIRK channel function in midbrain DA neurons correlated with decreased and increased sensitivity, respectively, to the motor-stimulatory effect of systemic morphine. Collectively, these data support the contention that the unique GIRK channel subtype in VTA DA neurons, the GIRK2/GIRK3 heteromer, regulates the sensitivity of the mouse mesolimbic DA system to drugs with addictive potential. PMID:25948263

  8. Motor control theories and their applications.

    PubMed

    Latash, Mark L; Levin, Mindy F; Scholz, John P; Schöner, Gregor

    2010-01-01

    We describe several influential hypotheses in the field of motor control including the equilibrium-point (referent configuration) hypothesis, the uncontrolled manifold hypothesis, and the idea of synergies based on the principle of motor abundance. The equilibrium-point hypothesis is based on the idea of control with thresholds for activation of neuronal pools; it provides a framework for analysis of both voluntary and involuntary movements. In particular, control of a single muscle can be adequately described with changes in the threshold of motor unit recruitment during slow muscle stretch (threshold of the tonic stretch reflex). Unlike the ideas of internal models, the equilibrium-point hypothesis does not assume neural computations of mechanical variables. The uncontrolled manifold hypothesis is based on the dynamic system approach to movements; it offers a toolbox to analyze synergic changes within redundant sets of elements related to stabilization of potentially important performance variables. The referent configuration hypothesis and the principle of abundance can be naturally combined into a single coherent scheme of control of multi-element systems. A body of experimental data on healthy persons and patients with movement disorders are reviewed in support of the mentioned hypotheses. In particular, movement disorders associated with spasticity are considered as consequences of an impaired ability to shift threshold of the tonic stretch reflex within the whole normal range. Technical details and applications of the mentioned hypo-theses to studies of motor learning are described. We view the mentioned hypotheses as the most promising ones in the field of motor control, based on a solid physical and neurophysiological foundation. PMID:20944446

  9. Comparison of Heart Rate Response to Tennis Activity between Persons with and without Spinal Cord Injuries: Implications for a Training Threshold

    ERIC Educational Resources Information Center

    Barfield, J. P.; Malone, Laurie A.; Coleman, Tristica A.

    2009-01-01

    The purpose of this study was to evaluate the ability of individuals with spinal cord injury (SCI) to reach a training threshold during on-court sport activity. Monitors collected heart rate (HR) data every 5 s for 11 wheelchair tennis players (WCT) with low paraplegia and 11 able-bodied controls matched on experience and skill level (ABT).…

  10. Overexpression of spermidine/spermine N1-acetyltransferase elevates the threshold to pentylenetetrazol-induced seizure activity in transgenic mice.

    PubMed

    Kaasinen, Selma K; Gröhn, Olli H J; Keinänen, Tuomo A; Alhonen, Leena; Jänne, Juhani

    2003-10-01

    Activation of polyamine catabolism in transgenic mice through an overexpression of spermidine/spermine N(1)-acetyltransferase (SSAT) results in a massive overaccumulation of the diamine putrescine in most tissues including brain. Putrescine pool in transgenic animals was strikingly expanded in every six brain regions analyzed at present. Pons (23-fold), cerebellum (37-fold), cerebrum (34-fold), and hippocampus (16-fold) showed the greatest increases in putrescine levels. Moreover, the molar ratio of putrescine to spermidine was increased in the different brain regions of the transgenic animals on an average of nearly 40-fold. Upon an exposure of the animals to pentylenetetrazol (PTZ) infusions, a compound known to induce epilepsy-like seizure activity, the SSAT transgenic mice showed significantly elevated seizure threshold to both clonic and tonic convulsions in comparison with their syngenic littermates. This difference, however, disappeared when the animals were treated with ifenprodil prior to PTZ infusions. The latter compound acts as an antagonist of N-methyl-D-aspartate receptor by binding to the polyamine site of the receptor. Overexpression of SSAT likewise appeared to protect the transgenic animals from PTZ-induced neuron loss in the hippocampus. As putrescine is known to serve as a precursor to gamma-aminobutyric acid (GABA), we carried out (1)H NMR analyses the results of which revealed that the levels of the inhibitory amino acid GABA and its excitatory counterpart glutamate were indistinguishable in syngenic and transgenic animals in all brain regions analyzed. The present results suggest that the frequently observed enhanced accumulation of putrescine in response to brain insults belongs to neuroprotective measures rather than being a cause of the subsequent injury. PMID:14552906

  11. A system for automatic recording and analysis of motor activity in rats.

    PubMed

    Heredia-López, Francisco J; May-Tuyub, Rossana M; Bata-García, José L; Góngora-Alfaro, José L; Alvarez-Cervera, Fernando J

    2013-03-01

    We describe the design and evaluation of an electronic system for the automatic recording of motor activity in rats. The device continually locates the position of a rat inside a transparent acrylic cube (50 cm/side) with infrared sensors arranged on its walls so as to correspond to the x-, y-, and z-axes. The system is governed by two microcontrollers. The raw data are saved in a text file within a secure digital memory card, and offline analyses are performed with a library of programs that automatically compute several parameters based on the sequence of coordinates and the time of occurrence of each movement. Four analyses can be made at specified time intervals: traveled distance (cm), movement speed (cm/s), time spent in vertical exploration (s), and thigmotaxis (%). In addition, three analyses are made for the total duration of the experiment: time spent at each x-y coordinate pair (min), time spent on vertical exploration at each x-y coordinate pair (s), and frequency distribution of vertical exploration episodes of distinct durations. User profiles of frequently analyzed parameters may be created and saved for future experimental analyses, thus obtaining a full set of analyses for a group of rats in a short time. The performance of the developed system was assessed by recording the spontaneous motor activity of six rats, while their behaviors were simultaneously videotaped for manual analysis by two trained observers. A high and significant correlation was found between the values measured by the electronic system and by the observers. PMID:22707401

  12. Effect of Imperatorin on the Spontaneous Motor Activity of Rat Isolated Jejunum Strips

    PubMed Central

    Mendel, Marta; Skalicka-Woźniak, Krystyna; Chłopecka, Magdalena; Dziekan, Natalia

    2015-01-01

    Imperatorin, a psoralen-type furanocoumarin, is a potent myorelaxant agent acting as a calcium antagonist on vascular smooth muscle. Its effects on other types of smooth muscle remain unknown. Therefore, the aim of this study was to investigate the hypothesized myorelaxant effect of imperatorin on gut motor activity and, possibly, to define the underlying mechanism of action. Imperatorin was made available for pharmacological studies from the fruits of the widely available Angelica officinalis through the application of high-performance countercurrent chromatography (HPCCC). Imperatorin generated reversible relaxation of jejunum strips dose-dependently (1–100 μM). At 25 and 50 μM, imperatorin caused relaxation comparable to the strength of the reaction induced by isoproterenol (Isop) at 0.1 μM. The observed response resulted neither from the activation of soluble guanylate cyclase, nor from β-adrenoreceptor involvement, nor from Ca2+-activated potassium channels. Imperatorin relaxed intestine strips precontracted with high potassium concentration, attenuated the force and duration of K+-induced contractions, and modulated the response of jejunum strips to acetylcholine. The results suggest that imperatorin probably interacts with various Ca2+ influx pathways in intestine smooth muscle. The types of some calcium channels involved in the activity of imperatorin will be examined in a subsequent study. PMID:26236380

  13. Low threshold, actively Q-switched Nd 3+:YVO 4 self-Raman laser and frequency doubled 588 nm yellow laser

    NASA Astrophysics Data System (ADS)

    Wang, Baoshan; Tan, Huiming; Peng, Jiying; Miao, Jieguang; Gao, Lanlan

    2007-03-01

    We reported an actively Q-switched, intracavity Nd3+:YVO4 self-Raman laser at 1176 nm with low threshold and high efficiency. From the extracavity frequency doubling by use of LBO nonlinear crystal, over 3.5 mW, 588 nm yellow laser is achieved. The maximum Raman laser output at is 182 mW with 1.8 W incident pump power. The threshold is only 370 mW at a pulse repetition frequency of 5 kHz. The optical conversion efficiency from incident to the Raman laser is 10%, and 1.9% from Raman laser to the yellow.

  14. Adaptive thresholding for reliable topological inference in single subject fMRI analysis.

    PubMed

    Gorgolewski, Krzysztof J; Storkey, Amos J; Bastin, Mark E; Pernet, Cyril R

    2012-01-01

    Single subject fMRI has proved to be a useful tool for mapping functional areas in clinical procedures such as tumor resection. Using fMRI data, clinicians assess the risk, plan and execute such procedures based on thresholded statistical maps. However, because current thresholding methods were developed mainly in the context of cognitive neuroscience group studies, most single subject fMRI maps are thresholded manually to satisfy specific criteria related to single subject analyzes. Here, we propose a new adaptive thresholding method which combines Gamma-Gaussian mixture modeling with topological thresholding to improve cluster delineation. In a series of simulations we show that by adapting to the signal and noise properties, the new method performs well in terms of total number of errors but also in terms of the trade-off between false negative and positive cluster error rates. Similarly, simulations show that adaptive thresholding performs better than fixed thresholding in terms of over and underestimation of the true activation border (i.e., higher spatial accuracy). Finally, through simulations and a motor test-retest study on 10 volunteer subjects, we show that adaptive thresholding improves reliability, mainly by accounting for the global signal variance. This in turn increases the likelihood that the true activation pattern can be determined offering an automatic yet flexible way to threshold single subject fMRI maps. PMID:22936908

  15. Association between daily activities, process skills, and motor skills in community-dwelling patients after left hemiparetic stroke

    PubMed Central

    Ahn, Sinae

    2016-01-01

    [Purpose] The purpose of this study was to evaluate the relationships between daily activities, information processing, and motor skills in individuals with hemineglect after having a left hemiparetic stroke. [Subjects and Methods] The instrumental activities of daily living of 35 patients (22 male and 13 female; age: 57.1 ± 16.9 years) with hemineglect after having a left hemiparetic stroke were assessed by using three clinical measurement tools, including activity card sorting, assessment of motor and process skills, and the modified Barthel Index. [Results] The results of the regression analysis indicated that the patients’ processing skills in instrumental activities of daily living after having a left hemiparetic stroke were reduced. Participation in leisure and social activities was also affected as assessed by using the modified Barthel Index. [Conclusion] This study supports the clinical need for rehabilitation intervention after a left hemiparetic stroke to improve patients’ processing skills and independence in performing activities of daily living. PMID:27390426

  16. Motor ability and weight status are determinants of out-of-school activity participation for children with developmental coordination disorder.

    PubMed

    Fong, Shirley S M; Lee, Velma Y L; Chan, Nerita N C; Chan, Rachel S H; Chak, Wai-Kwong; Pang, Marco Y C

    2011-01-01

    According to the International Classification of Functioning, Disability and Health model endorsed by the World Health Organization, participation in everyday activities is integral to normal child development. However, little is known about the influence of motor ability and weight status on physical activity participation in children with developmental coordination disorder (DCD). This study aimed to (1) compare motor performance, weight status and pattern of out-of-school activity participation between children with DCD and those without; and (2) identify whether motor ability and weight status were determinants of participation patterns among children with DCD. We enrolled 81 children with DCD (boys, n = 63; girls, n = 18; mean age, 8.07 ± 1.5 years) and 67 typically developing children (boys, n = 48; girls, n = 19; mean age, 8.25 ± 1.6 years). Participation patterns (diversity, intensity, companionship, location, and enjoyment) were evaluated with the Children Assessment of Participation and Enjoyment. Motor ability was evaluated with the Movement Assessment Battery for Children, second edition (MABC-2). Other factors that may influence participation such as age, gender, and body weight were also recorded. Analysis of variance was used to compare outcome variables of the two groups, and significant determinants of activity participation were identified by multiple regression analysis. Children with DCD participated in fewer activities (i.e., limited participation diversity) and participated less frequently (i.e., limited participation intensity) than their typically developing peers; however, companionship, location of participation, and enjoyment level did not differ between the two groups. Children in the DCD group demonstrated significantly worse motor ability as assessed by the MABC-2. Further, a greater proportion of children in the DCD group were in the overweight/obese category compared with their typically developing peers. After accounting for the

  17. A scaling approach to find order parameters quantifying the effects of dopaminergic agents on unconditioned motor activity in rats.

    PubMed

    Paulus, M P; Geyer, M A

    1991-01-01

    1. Three experiments were conducted in the Behavioral Pattern Monitor (BPM) to assess the effects of the D1 agonist SKF-38393, the D2 agonist quinpirole, and the interaction of the D2 antagonists haloperidol with amphetamine or cocaine on the amount, the structure, and the unpredictability of micro-events of rat exploratory behavior. 2. SKF-38393 (0.3, 1.0, 3.0, and 10.0 mg/kg) did not change the amount of motor behavior indicated by the temporal scaling exponent alpha, a descriptor of the local degree of acting, during a 60 min exposure in the BPM. However, SKF-38393 (3.0, and 10.0 mg/kg) significantly increased the spatial scaling exponent d, indicating an increased component of local circumscribed movements. 3. Quinpirole (0.03, 0.1, 0.3, and 1.0 mg/kg) produced a biphasic dose response with respect to the amount of motor behavior. Low doses (0.03, 0.1) significantly decreased the local degree of acting, whereas alpha returned to control group levels for higher doses (0.3, 1.0 mg/kg). The change in activity was accompanied by a significant increase of local movements, i.e. d was increased for the lower doses. 4. Haloperidol (15.0 micrograms/kg) reduced a slightly increased d measure for amphetamine (1.0 mg/kg) treated animals and increased a significantly reduced d for cocaine (20.0 mg/kg) treated animals, without affecting the increases of motor activity induced by both treatments. 5. It is concluded that the structure of motor activity provides an important measure of unconditioned motor behavior, which can be affected independently of the typically measured amount of motor activity. PMID:1684875

  18. A positive association between active lifestyle and hemispheric lateralization for motor control and learning in older adults.

    PubMed

    Wang, Jinsung; D'Amato, Arthur; Bambrough, Jennifer; Swartz, Ann M; Miller, Nora E

    2016-11-01

    Physical activity (PA) is well known to have general health benefits for older adults, but it is unclear whether it can also positively affect brain function involved in motor control and learning. We have previously shown that interlimb transfer of visuomotor adaptation occurs asymmetrically in young adults, while that occurs symmetrically in older adults, which suggests that the lateralized function of each hemisphere during motor tasks is diminished with aging. Here, we investigated the association between the level of PA and hemispheric motor lateralization by comparing the pattern of interlimb transfer following visuomotor adaptation between physically active and inactive older adults. Subjects were divided into two groups based on their PA level (active, inactive). They were further divided into two groups, such that a half of the subjects in each group adapted to a 30° rotation during targeted reaching movements with the left arm first, then with the right arm; and the other half with the right arm first, then with the left arm. Results indicated asymmetrical transfer (from left to right only) in the active subjects, whereas symmetrical transfer (from left to right, and vice versa) was observed in the inactive subjects. These findings suggest that older adults who maintain active lifestyle have a central nervous system that is more intact in terms of its lateralized motor function as compared with those who are inactive. PMID:27481694

  19. Approximation of the first passage time density of a Wiener process to an exponentially decaying boundary by two-piecewise linear threshold. Application to neuronal spiking activity.

    PubMed

    Tamborrino, Massimiliano

    2016-06-01

    The first passage time density of a diffusion process to a time varying threshold is of primary interest in different fields. Here, we consider a Brownian motion in presence of an exponentially decaying threshold to model the neuronal spiking activity. Since analytical expressions of the first passage time density are not available, we propose to approximate the curved boundary by means of a continuous two-piecewise linear threshold. Explicit expressions for the first passage time density towards the new boundary are provided. First, we introduce different approximating linear thresholds. Then, we describe how to choose the optimal one minimizing the distance to the curved boundary, and hence the error in the corresponding passage time density. Theoretical means, variances and coefficients of variation given by our method are compared with empirical quantities from simulated data. Moreover, a further comparison with firing statistics derived under the assumption of a small amplitude of the time-dependent change in the threshold, is also carried out. Finally, maximum likelihood and moment estimators of the parameters of the model are derived and applied on simulated data. PMID:27106189

  20. Phasic Motor Activity of Respiratory and Non-Respiratory Muscles in REM Sleep

    PubMed Central

    Fraigne, Jimmy J.; Orem, John M.

    2011-01-01

    data. There is a drive in REM sleep that affects specifically respiratory muscles. The characteristic increase in respiratory frequency during REM sleep is induced by this drive. Citation: Fraigne JJ; Orem JM. Phasic motor activity of respiratory and non-respiratory muscles in REM sleep. SLEEP 2011;34(4):425-434. PMID:21461320

  1. Prolonged activity evokes potentiation and the "sag" phenomenon in slow motor units of rat soleus.

    PubMed

    Drzymała-Celichowska, Hanna; Raikova, Rositsa; Krutki, Piotr

    2016-01-01

    Slow motor units (MUs) have no sag in their unfused tetani. This study in anesthetized rats shows that the sag can be observed in slow soleus MUs after prolonged activity. Twitches and unfused tetanic contractions were recorded from male (n=35) and female (n=39) MUs before and after the four minutes of the fatigue test (trains of 13 pulses at 40 Hz repeated every second). After this activity twitch contractions potentiated and a shift in the steep part of the force-frequency curve towards lower frequencies was observed in both sexes. Initially no sag was visible in unfused tetani, but after the fatigue test the phenomenon was observed in 77% of male, while in 13% of female MUs, the result consistent with the previously reported higher content of IIa myosin and faster contraction of MUs in male soleus. The decomposition of tetani with sag into trains of twitch-shape responses to consecutive stimuli revealed higher forces of initial decomposed twitches than later. The revealed alterations the force development due to long-lasting activation of slow MUs were sex-related and more pronounced in male soleus. PMID:27373952

  2. Tum/RacGAP functions as a switch activating the Pav/kinesin-6 motor.

    PubMed

    Tao, Li; Fasulo, Barbara; Warecki, Brandt; Sullivan, William

    2016-01-01

    Centralspindlin is essential for central spindle and cleavage furrow formation. Drosophila centralspindlin consists of a kinesin-6 motor (Pav/kinesin-6) and a GTPase-activating protein (Tum/RacGAP). Centralspindlin localization to the central spindle is mediated by Pav/kinesin-6. While Tum/RacGAP has well-documented scaffolding functions, whether it influences Pav/kinesin-6 function is less well-explored. Here we demonstrate that both Pav/kinesin-6 and the centralspindlin complex (co-expressed Pav/Tum) have strong microtubule bundling activity. Centralspindlin also has robust plus-end-directed motility. In contrast, Pav/kinesin-6 alone cannot move microtubules. However, the addition of Tum/RacGAP or a 65 amino acid Tum/RacGAP fragment to Pav/kinesin-6 restores microtubule motility. Further, ATPase assays reveal that microtubule-stimulated ATPase activity of centralspindlin is seven times higher than that of Pav/kinesin-6. These findings are supported by in vivo studies demonstrating that in Tum/RacGAP-depleted S2 Drosophila cells, Pav/kinesin-6 exhibits severely reduced localization to the central spindle and an abnormal concentration at the centrosomes. PMID:27091402

  3. Tum/RacGAP functions as a switch activating the Pav/kinesin-6 motor

    PubMed Central

    Tao, Li; Fasulo, Barbara; Warecki, Brandt; Sullivan, William

    2016-01-01

    Centralspindlin is essential for central spindle and cleavage furrow formation. Drosophila centralspindlin consists of a kinesin-6 motor (Pav/kinesin-6) and a GTPase-activating protein (Tum/RacGAP). Centralspindlin localization to the central spindle is mediated by Pav/kinesin-6. While Tum/RacGAP has well-documented scaffolding functions, whether it influences Pav/kinesin-6 function is less well-explored. Here we demonstrate that both Pav/kinesin-6 and the centralspindlin complex (co-expressed Pav/Tum) have strong microtubule bundling activity. Centralspindlin also has robust plus-end-directed motility. In contrast, Pav/kinesin-6 alone cannot move microtubules. However, the addition of Tum/RacGAP or a 65 amino acid Tum/RacGAP fragment to Pav/kinesin-6 restores microtubule motility. Further, ATPase assays reveal that microtubule-stimulated ATPase activity of centralspindlin is seven times higher than that of Pav/kinesin-6. These findings are supported by in vivo studies demonstrating that in Tum/RacGAP-depleted S2 Drosophila cells, Pav/kinesin-6 exhibits severely reduced localization to the central spindle and an abnormal concentration at the centrosomes. PMID:27091402

  4. Advances in selective activation of muscles for non-invasive motor neuroprostheses.

    PubMed

    Koutsou, Aikaterini D; Moreno, Juan C; Del Ama, Antonio J; Rocon, Eduardo; Pons, José L

    2016-01-01

    Non-invasive neuroprosthetic (NP) technologies for movement compensation and rehabilitation remain with challenges for their clinical application. Two of those major challenges are selective activation of muscles and fatigue management. This review discusses how electrode arrays improve the efficiency and selectivity of functional electrical stimulation (FES) applied via transcutaneous electrodes. In this paper we review the principles and achievements during the last decade on techniques for artificial motor unit recruitment to improve the selective activation of muscles. We review the key factors affecting the outcome of muscle force production via multi-pad transcutaneous electrical stimulation and discuss how stimulation parameters can be set to optimize external activation of body segments. A detailed review of existing electrode array systems proposed by different research teams is also provided. Furthermore, a review of the targeted applications of existing electrode arrays for control of upper and lower limb NPs is provided. Eventually, last section demonstrates the potential of electrode arrays to overcome the major challenges of NPs for compensation and rehabilitation of patient-specific impairments. PMID:27296478

  5. Activation of α2A-Containing Nicotinic Acetylcholine Receptors Mediates Nicotine-Induced Motor Output in Embryonic Zebrafish

    PubMed Central

    Menelaou, Evdokia; Udvadia, Ava J.; Tanguay, Robert L.; Svoboda, Kurt R.

    2014-01-01

    It is well established that cholinergic signaling has critical roles during central nervous system development. In physiological and behavioral studies, activation of nicotinic acetylcholine receptors has been implicated in mediating cholinergic signaling. In developing spinal cord, cholinergic transmission is associated with neural circuits responsible for producing locomotor behaviors. In this study, we investigated the expression pattern of the α2A nAChR subunit as evidence from others suggested it could be expressed by spinal neurons. In situ hybridization and immunohistochemistry revealed that the α2A nAChR subunits are expressed in spinal Rohon-Beard (RB) neurons and olfactory sensory neurons in young embryos. In order to examine the functional role of the α2A nAChR subunit during embryogenesis, we blocked its expression using antisense modified oligonucleotides. Blocking the expression of α2A nAChR subunits had no effect on spontaneous motor activity. However, it did alter the embryonic nicotine-induced motor output. This reduction in motor activity was not accompanied by defects in neuronal and muscle elements associated with the motor output. Moreover, the anatomy and functionality of RB neurons was normal even in the absence of the α2A nAChR subunit. Thus, we propose that α2A-containing nAChR are dispensable for normal RB development. However, in the context of nicotine-induced motor output, α2A-containing nAChRs on RB neurons provide the substrate that nicotine acts upon to induce the motor output. These findings also indicate that functional neuronal nAChRs are present within spinal cord at the time when locomotor output in zebrafish first begins to manifest itself. PMID:24738729

  6. EXEL; Experience for Children in Learning. Parent-Directed Activities to Develop: Oral Expression, Visual Discrimination, Auditory Discrimination, Motor Coordination.

    ERIC Educational Resources Information Center

    Behrmann, Polly; Millman, Joan

    The activities collected in this handbook are planned for parents to use with their children in a learning experience. They can also be used in the classroom. Sections contain games designed to develop visual discrimination, auditory discrimination, motor coordination and oral expression. An objective is given for each game, and directions for…

  7. The Importance of Motor Functional Levels from the Activity Limitation Perspective of ICF in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Mutlu, Akmer

    2010-01-01

    Our purpose in this study was to evaluate performance and capacity as defined by Gross Motor Function Classification System (GMFCS) and Manual Ability Classification System (MACS) from the "activity limitation" perspective of International Classification of Functioning, Disability, and Health (ICF) and to investigate the relationship between the…

  8. Directly Observed Physical Activity and Fundamental Motor Skills in Four-Year-Old Children in Day Care

    ERIC Educational Resources Information Center

    Iivonen, S.; Sääkslahti, A. K.; Mehtälä, A.; Villberg, J. J.; Soini, A.; Poskiparta, M.

    2016-01-01

    Physical activity (PA), its location, social interactions and fundamental motor skills (FMS) were investigated in four-year-old Finnish children in day care. Six skills in the stability, locomotor and manipulative domains were assessed in 53 children (24 boys, 29 girls, normal anthropometry) with the APM-Inventory manual for assessing children's…

  9. The Role of Motor Competence and Body Mass Index in Children's Activity Levels in Physical Education Classes

    ERIC Educational Resources Information Center

    Spessato, Barbara Coiro; Gabbard, Carl; Valentini, Nadia C.

    2013-01-01

    Our goal was to investigate the role of body mass index (BMI) and motor competence (MC) in children's physical activity (PA) levels during physical education (PE) classes. We assessed PA levels of 5-to-10-year old children ("n" = 264) with pedometers in four PE classes. MC was assessed using the TGMD-2 and BMI values were classified according to…

  10. COMPARISON OF NICOTINIC ANTAGONISTS IN BLOCKING THE EFFECT OF ANATOXIN-A AND NICOTINE ON THE MOTOR ACTIVITY OF RATS.

    EPA Science Inventory

    Anatoxin-a is a potent nicotinic agonist produced by many species and genera of cyanobacteria. Previous research showed that both anatoxin-a and nicotine produce dose-related decreases in the motor activity of rats. The two toxins differed, however, in their effects with weekly a...

  11. Mapping the spatio-temporal structure of motor cortical LFP and spiking activities during reach-to-grasp movements

    PubMed Central

    Riehle, Alexa; Wirtssohn, Sarah; Grün, Sonja; Brochier, Thomas

    2013-01-01

    Grasping an object involves shaping the hand and fingers in relation to the object’s physical properties. Following object contact, it also requires a fine adjustment of grasp forces for secure manipulation. Earlier studies suggest that the control of hand shaping and grasp force involve partially segregated motor cortical networks. However, it is still unclear how information originating from these networks is processed and integrated. We addressed this issue by analyzing massively parallel signals from population measures (local field potentials, LFPs) and single neuron spiking activities recorded simultaneously during a delayed reach-to-grasp task, by using a 100-electrode array chronically implanted in monkey motor cortex. Motor cortical LFPs exhibit a large multi-component movement-related potential (MRP) around movement onset. Here, we show that the peak amplitude of each MRP component and its latency with respect to movement onset vary along the cortical surface covered by the array. Using a comparative mapping approach, we suggest that the spatio-temporal structure of the MRP reflects the complex physical properties of the reach-to-grasp movement. In addition, we explored how the spatio-temporal structure of the MRP relates to two other measures of neuronal activity: the temporal profile of single neuron spiking activity at each electrode site and the somatosensory receptive field properties of single neuron activities. We observe that the spatial representations of LFP and spiking activities overlap extensively and relate to the spatial distribution of proximal and distal representations of the upper limb. Altogether, these data show that, in motor cortex, a precise spatio-temporal pattern of activation is involved for the control of reach-to-grasp movements and provide some new insight about the functional organization of motor cortex during reaching and object manipulation. PMID:23543888

  12. Identification of Inhibitory Premotor Interneurons Activated at a Late Phase in a Motor Cycle during Drosophila Larval Locomotion

    PubMed Central

    Itakura, Yuki; Kohsaka, Hiroshi; Ohyama, Tomoko; Zlatic, Marta

    2015-01-01

    Rhythmic motor patterns underlying many types of locomotion are thought to be produced by central pattern generators (CPGs). Our knowledge of how CPG networks generate motor patterns in complex nervous systems remains incomplete, despite decades of work in a variety of model organisms. Substrate borne locomotion in Drosophila larvae is driven by waves of muscular contraction that propagate through multiple body segments. We use the motor circuitry underlying crawling in larval Drosophila as a model to try to understand how segmentally coordinated rhythmic motor patterns are generated. Whereas muscles, motoneurons and sensory neurons have been well investigated in this system, far less is known about the identities and function of interneurons. Our recent study identified a class of glutamatergic premotor interneurons, PMSIs (period-positive median segmental interneurons), that regulate the speed of locomotion. Here, we report on the identification of a distinct class of glutamatergic premotor interneurons called Glutamatergic Ventro-Lateral Interneurons (GVLIs). We used calcium imaging to search for interneurons that show rhythmic activity and identified GVLIs as interneurons showing wave-like activity during peristalsis. Paired GVLIs were present in each abdominal segment A1-A7 and locally extended an axon towards a dorsal neuropile region, where they formed GRASP-positive putative synaptic contacts with motoneurons. The interneurons expressed vesicular glutamate transporter (vGluT) and thus likely secrete glutamate, a neurotransmitter known to inhibit motoneurons. These anatomical results suggest that GVLIs are premotor interneurons that locally inhibit motoneurons in the same segment. Consistent with this, optogenetic activation of GVLIs with the red-shifted channelrhodopsin, CsChrimson ceased ongoing peristalsis in crawling larvae. Simultaneous calcium imaging of the activity of GVLIs and motoneurons showed that GVLIs’ wave-like activity lagged behind that of

  13. Young Zanzibari Children with Iron Deficiency, Iron Deficiency Anemia, Stunting, or Malaria Have Lower Motor Activity Scores and Spend Less Time in Locomotion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Motor activity improves cognitive and social-emotional development through a child’s exploration of his or her physical and social environment. This study assessed anemia, iron deficiency, hemoglobin (Hb), length-for-age Z-score (LAZ), and malaria infection as predictors of motor activity in 771 chi...

  14. Mitochondrial threshold effects.

    PubMed Central

    Rossignol, Rodrigue; Faustin, Benjamin; Rocher, Christophe; Malgat, Monique; Mazat, Jean-Pierre; Letellier, Thierry

    2003-01-01

    The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the 'phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the 'biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a 'translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases. PMID:12467494

  15. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    NASA Astrophysics Data System (ADS)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  16. Sub-terahertz microsecond optically controlled switch with GaAs active element beyond the photoelectric threshold

    NASA Astrophysics Data System (ADS)

    Kulygin, M.; Denisov, G.; Vlasova, K.; Andreev, N.; Shubin, S.; Salahetdinov, S.

    2016-01-01

    We study an unusual working regime of a recently developed sub-terahertz microwave cavity-based switch. The resonator cavity includes a semiconductor plate which is illuminated by laser emission beyond the photoelectric threshold. Despite a significant change to the conventional process of photoelectric effect we have found that the switch works. Typical switching performance rate is about 1 μs for the regime. A process of carrier density relaxation beyond the photoelectric threshold is discussed. An idea of diagnostic method for the semiconductor's quality is proposed.

  17. Sub-terahertz microsecond optically controlled switch with GaAs active element beyond the photoelectric threshold.

    PubMed

    Kulygin, M; Denisov, G; Vlasova, K; Andreev, N; Shubin, S; Salahetdinov, S

    2016-01-01

    We study an unusual working regime of a recently developed sub-terahertz microwave cavity-based switch. The resonator cavity includes a semiconductor plate which is illuminated by laser emission beyond the photoelectric threshold. Despite a significant change to the conventional process of photoelectric effect we have found that the switch works. Typical switching performance rate is about 1 μs for the regime. A process of carrier density relaxation beyond the photoelectric threshold is discussed. An idea of diagnostic method for the semiconductor's quality is proposed. PMID:26827338

  18. The Homeostatic Interaction Between Anodal Transcranial Direct Current Stimulation and Motor Learning in Humans is Related to GABAA Activity

    PubMed Central

    Amadi, Ugwechi; Allman, Claire; Johansen-Berg, Heidi; Stagg, Charlotte J.

    2015-01-01

    Background The relative timing of plasticity-induction protocols is known to be crucial. For example, anodal transcranial direct current stimulation (tDCS), which increases cortical excitability and typically enhances plasticity, can impair performance if it is applied before a motor learning task. Such timing-dependent effects have been ascribed to homeostatic plasticity, but the specific synaptic site of this interaction remains unknown. Objective We wished to investigate the synaptic substrate, and in particular the role of inhibitory signaling, underpinning the behavioral effects of anodal tDCS in homeostatic interactions between anodal tDCS and motor learning. Methods We used transcranial magnetic stimulation (TMS) to investigate cortical excitability and inhibitory signaling following tDCS and motor learning. Each subject participated in four experimental sessions and data were analyzed using repeated measures ANOVAs and post-hoc t-tests as appropriate. Results As predicted, we found that anodal tDCS prior to the motor task decreased learning rates. This worsening of learning after tDCS was accompanied by a correlated increase in GABAA activity, as measured by TMS-assessed short interval intra-cortical inhibition (SICI). Conclusion This provides the first direct demonstration in humans that inhibitory synapses are the likely site for the interaction between anodal tDCS and motor learning, and further, that homeostatic plasticity at GABAA synapses has behavioral relevance in humans. PMID:26279408

  19. Strain Mediated Adaptation Is Key for Myosin Mechanochemistry: Discovering General Rules for Motor Activity

    PubMed Central

    Jana, Biman; Onuchic, José N.

    2016-01-01

    A structure-based model of myosin motor is built in the same spirit of our early work for kinesin-1 and Ncd towards physical understanding of its mechanochemical cycle. We find a structural adaptation of the motor head domain in post-powerstroke state that signals faster ADP release from it compared to the same from the motor head in the pre-powerstroke state. For dimeric myosin, an additional forward strain on the trailing head, originating from the postponed powerstroke state of the leading head in the waiting state of myosin, further increases the rate of ADP release. This coordination between the two heads is the essence of the processivity of the cycle. Our model provides a structural description of the powerstroke step of the cycle as an allosteric transition of the converter domain in response to the Pi release. Additionally, the variation in structural elements peripheral to catalytic motor domain is the deciding factor behind diverse directionalities of myosin motors (myosin V & VI). Finally, we observe that there are general rules for functional molecular motors across the different families. Allosteric structural adaptation of the catalytic motor head in different nucleotide states is crucial for mechanochemistry. Strain-mediated coordination between motor heads is essential for processivity and the variation of peripheral structural elements is essential for their diverse functionalities. PMID:27494025

  20. A Strategy for Embedding Functional Motor and Early Numeracy Skill Instruction into Physical Education Activities

    ERIC Educational Resources Information Center

    Whinnery, Stacie B.; Whinnery, Keith W.; Eddins, Daisy

    2016-01-01

    This article addresses the challenges educators face when attempting to find a balance between both functional and academic skill instruction for students with severe, multiple disabilities including motor impairments. The authors describe a strategy that employs embedded instruction of early numeracy and functional motor skills during physical…

  1. Effects of Motor Activity on Children's Intentional and Incidental Memory for Spatial Locations.

    ERIC Educational Resources Information Center

    Herman, James F.; And Others

    1982-01-01

    Examines (1) the effect of increased motor involvement with an environment on children's memory for spatial locations, and (2) the effect of different degrees of motor involvement under intentional and incidental memory conditions. Thirty boys and 30 girls at each of kindergarten and third-grade levels were individually tested in a large-scale,…

  2. Strain Mediated Adaptation Is Key for Myosin Mechanochemistry: Discovering General Rules for Motor Activity.

    PubMed

    Jana, Biman; Onuchic, José N

    2016-08-01

    A structure-based model of myosin motor is built in the same spirit of our early work for kinesin-1 and Ncd towards physical understanding of its mechanochemical cycle. We find a structural adaptation of the motor head domain in post-powerstroke state that signals faster ADP release from it compared to the same from the motor head in the pre-powerstroke state. For dimeric myosin, an additional forward strain on the trailing head, originating from the postponed powerstroke state of the leading head in the waiting state of myosin, further increases the rate of ADP release. This coordination between the two heads is the essence of the processivity of the cycle. Our model provides a structural description of the powerstroke step of the cycle as an allosteric transition of the converter domain in response to the Pi release. Additionally, the variation in structural elements peripheral to catalytic motor domain is the deciding factor behind diverse directionalities of myosin motors (myosin V & VI). Finally, we observe that there are general rules for functional molecular motors across the different families. Allosteric structural adaptation of the catalytic motor head in different nucleotide states is crucial for mechanochemistry. Strain-mediated coordination between motor heads is essential for processivity and the variation of peripheral structural elements is essential for their diverse functionalities. PMID:27494025

  3. Fundamental motor skill, physical activity, and sedentary behavior in socioeconomically disadvantaged kindergarteners.

    PubMed

    Gu, Xiangli

    2016-10-01

    Guided by Stodden et al's conceptual model, the main purpose of the study was to examine the relation between fundamental motor skills (FMS; locomotor and objective control skills), different intensity levels of physical activity (light PA [LPA], moderate-to-vigorous PA [MVPA], and vigorous PA[VPA]), and sedentary behavior (SB) in socioeconomically disadvantaged kindergarteners. A prospective design was used in this study and the data were collected across the 2013-2014 academic school year. Participants were 256 (129 boys; 127 girls; Mage = 5.37, SD = 0.48) kindergarteners recruited from three public schools in the southern United States. Results found that FMS were significantly related to LPA, MVPA, VPA, and SB. Regression analyses indicate that locomotor skills explained significant variance for LPA (6.4%; p < .01), MVPA (7.9%; p < .001), and VPA (5.3%; p < .01) after controlling for weight status. Mediational analysis supports the significant indirect effect of MVPA on the relation between FMS and SB (95% CI: [-0.019, -0.006]). Adequate FMS development during early childhood may result in participating in more varied physical activities, thus leading to lower risk of obesity-related behaviors. PMID:26691744

  4. Review of Physics Related Research and Development Activities in Nondestructive Characterization of Solid Rocket Motor Materials

    NASA Astrophysics Data System (ADS)

    Pearson, Lee H.

    1998-10-01

    The perception that solid rocket motors (srm) are of relatively simple mechanical construction with a long history in private, military, and NASA applications may lead some to believe that little is left to be done in terms of basic and applied research and development in support of this technology. The fact is that srm?s are very complicated primarily because of the complexity of the materials from which they are built. The reliability and performance of srm?s are determined by the ballistic and mechanical properties of each individual material component, and by the manufacturing processes that conjoin these materials. In order to insure reliability and good performance, there are on-going materials research and development activities in the srm community. Included are activities involving the development of nondestructive evaluation (NDE) methods used for materials and processes characterization. Typical applications include: detection and characterization of defects in fiber reinforced composite materials, detection of weak bonds and debonds, verification of surface cleanliness prior to bonding, characterization of aging materials and bondlines, measurement of elastic properties in filled polymeric materials, monitoring of cure in polymeric materials, and measurement of film or coating thicknesses. NDE methods and physics principles upon which they are based will be described. Challenges and future research and development directions will be identified.

  5. Multi-channel NIRS of the primary motor cortex to discriminate hand from foot activity

    NASA Astrophysics Data System (ADS)

    Koenraadt, K. L. M.; Duysens, J.; Smeenk, M.; Keijsers, N. L. W.

    2012-08-01

    The poor spatial resolution of near-infrared spectroscopy (NIRS) makes it difficult to distinguish two closely located cortical areas from each other. Here, a combination of multi-channel NIRS and a centre of gravity (CoG) approach (widely accepted in the field of transcranial magnetic stimulation; TMS) was used to discriminate between closely located cortical areas activated during hand and foot movements. Similarly, the possibility of separating the more anteriorly represented discrete movements from rhythmic movements was studied. Thirteen healthy right-handed subjects performed rhythmic or discrete (‘task’) hand or foot (‘extremity’) tapping. Hemodynamic responses were measured using an 8-channel NIRS setup. For oxyhemoglobin (OHb) and deoxyhemoglobin (HHb), a CoG was determined for each condition using the mean hemodynamic responses and the coordinates of the channels. Significant hemodynamic responses were found for hand and foot movements. Based on the HHb responses, the NIRS-CoG of hand movements was located 0.6 cm more laterally compared to the NIRS-CoG of foot movements. For OHb responses no difference in NIRS-CoG was found for ‘extremity’ nor for ‘task’. This is the first NIRS study showing hemodynamic responses for isolated foot movements. Furthermore, HHb responses have the potential to be used in multi-channel NIRS experiments requiring differential activation of motor cortex areas linked to either hand or foot movements.

  6. Motor-driven effective temperature and viscoelastic response of active matter.

    PubMed

    Morozov, Konstantin I; Pismen, Len M

    2010-06-01

    We consider dynamic response of a cytoskeletal network to both thermal and motor-induced fluctuations. The latter are viewed in two independent ways, as either additive or multiplicative colored noise. Due to a natural upper frequency limit of the motor agitation, the response of a living cell is similar to that of an equilibrium system in the high-frequency domain. At lower frequencies, the role of motor agitation manifests itself in intensified network fluctuations, which is equivalent to effective growth of the environment temperature. The effective temperature becomes frequency dependent, which signifies violation of the conventional fluctuation-dissipation theorem. The motor action affects the dynamic shear modulus in two opposite ways: by stiffening the network through filament prestress and softening it through increased agitation. The latter tendency is isolated when only single-headed motors are present. The theory is in good agreement with experimental measurements of the amplitude of the shear modulus under these conditions. PMID:20866455

  7. Remote control of myosin and kinesin motors using light-activated gearshifting.

    PubMed

    Nakamura, Muneaki; Chen, Lu; Howes, Stuart C; Schindler, Tony D; Nogales, Eva; Bryant, Zev

    2014-09-01

    Cytoskeletal motors perform critical force generation and transport functions in eukaryotic cells. Engineered modifications of motor function provide direct tests of protein structure-function relationships and potential tools for controlling cellular processes or for harnessing molecular transport in artificial systems. Here, we report the design and characterization of a panel of cytoskeletal motors that reversibly change gears--speed up, slow down or switch directions--when exposed to blue light. Our genetically encoded structural designs incorporate a photoactive protein domain to enable light-dependent conformational changes in an engineered lever arm. Using in vitro motility assays, we demonstrate robust spatiotemporal control over motor function and characterize the kinetics of the optical gearshifting mechanism. We have used a modular approach to create optical gearshifting motors for both actin-based and microtubule-based transport. PMID:25086603

  8. Remote control of myosin and kinesin motors using light-activated gearshifting

    PubMed Central

    Nakamura, Muneaki; Chen, Lu; Howes, Stuart C.; Schindler, Tony D.; Nogales, Eva

    2015-01-01

    Cytoskeletal motors perform critical force generation and transport functions in eukaryotic cells1,2. Engineered modifications of motor function provide direct tests of protein structure-function relationships and potential tools for controlling cellular processes or for harnessing molecular transport in artificial systems3,4. Here, we report the design and characterization of a panel of cytoskeletal motors that reversibly change gears—speed up, slow down or switch directions—when exposed to blue light. Our genetically encoded structural designs incorporate a photoactive protein domain to enable light-dependent conformational changes in an engineered lever arm. Using in vitro motility assays, we demonstrate robust spatiotemporal control over motor function and characterize the kinetics of the optical gearshifting mechanism. We have used a modular approach to create optical gearshifting motors for both actin-based and microtubule-based transport. PMID:25086603

  9. The effect of leisure activity golf practice on motor imagery: an fMRI study in middle adulthood.

    PubMed

    Bezzola, Ladina; Mérillat, Susan; Jäncke, Lutz

    2012-01-01

    Much is known about practice-induced plasticity of the motor system. But it is not clear how a physical training influences the mental rehearsal of the practiced task and its associated hemodynamic responses. In the present longitudinal study with two measurement time-points, we used the method of functional magnetic resonance imaging (fMRI) and a motor imagery task, in order to explore the dynamic neuro-functional changes induced by a highly complex physical training. The 11 golf novices between the age of 40 and 60 years practiced the motor training as leisure activity. Additionally, data from an age and sex-matched control group without golf training was collected. As a main result, we demonstrate that changes between the two measurement time-points were only found in the golf novice group. The golf novices showed a decrease in hemodynamic responses during the mental rehearsal of the golf swing in non-primary motor areas after the 40 h of golf practice. Thus, the results indicate that a complex physical leisure activity induces functional neuroplasticity in the seldom studied population of middle-aged adults, and that this effect is evident during mental rehearsal of the practiced task. This finding supports the idea that (a) a skill improvement is associated with a modified activation pattern in the associated neuronal network that can be identified during mental rehearsal of the practiced task, and that (b) a strict training protocol is not necessary to induce functional neuroplasticity. PMID:22479243

  10. The effect of leisure activity golf practice on motor imagery: an fMRI study in middle adulthood

    PubMed Central

    Bezzola, Ladina; Mérillat, Susan; Jäncke, Lutz

    2012-01-01

    Much is known about practice-induced plasticity of the motor system. But it is not clear how a physical training influences the mental rehearsal of the practiced task and its associated hemodynamic responses. In the present longitudinal study with two measurement time-points, we used the method of functional magnetic resonance imaging (fMRI) and a motor imagery task, in order to explore the dynamic neuro-functional changes induced by a highly complex physical training. The 11 golf novices between the age of 40 and 60 years practiced the motor training as leisure activity. Additionally, data from an age and sex-matched control group without golf training was collected. As a main result, we demonstrate that changes between the two measurement time-points were only found in the golf novice group. The golf novices showed a decrease in hemodynamic responses during the mental rehearsal of the golf swing in non-primary motor areas after the 40 h of golf practice. Thus, the results indicate that a complex physical leisure activity induces functional neuroplasticity in the seldom studied population of middle-aged adults, and that this effect is evident during mental rehearsal of the practiced task. This finding supports the idea that (a) a skill improvement is associated with a modified activation pattern in the associated neuronal network that can be identified during mental rehearsal of the practiced task, and that (b) a strict training protocol is not necessary to induce functional neuroplasticity. PMID:22479243

  11. Real-time tracking of motor response activation and response competition in a Stroop task in young children: a lateralized readiness potential study.

    PubMed

    Szucs, Dénes; Soltész, Fruzsina; Bryce, Donna; Whitebread, David

    2009-11-01

    The ability to select an appropriate motor response by resolving competition among alternative responses plays a major role in cognitive performance. fMRI studies suggest that the development of this skill is related to the maturation of the frontal cortex that underlies the improvement of motor inhibition abilities. However, fMRI cannot characterize the temporal properties of motor response competition and motor activation in general. We studied the development of the time course of resolving motor response competition. To this end, we used the lateralized readiness potential (LRP), an ERP measure, for tracking correct and incorrect motor cortex activation in children in real time. Fourteen children and 14 adults took part in an animal-size Stroop task where they selected between two animals, presented simultaneously on the computer screen, which was larger in real life. In the incongruent condition, the LRP detected stronger and longer lasting incorrect response activation in children than in adults. LRP results could explain behavioral congruency effects, the generally longer RT in children than in adults and the larger congruency effect in children than in adults. In contrast, the peak latency of ERP waves, usually associated with stimulus processing speed, could explain neither of the above effects. We conclude that the development of resolving motor response competition, relying on motor inhibition skills, is a crucial factor in child development. Our study demonstrates that the LRP is an excellent tool for studying motor activation in children. PMID:19296726

  12. Threshold Concepts as a Focus for Metalearning Activity: Application of a Research-Developed Mechanism in Undergraduate Engineering

    ERIC Educational Resources Information Center

    Meyer, Jan H. F.; Knight, David B.; Callaghan, David P.; Baldock, Tom E.

    2015-01-01

    This paper reports on the development of metalearning capacity in the learning of a "threshold concept"--capacity of transformative significance relative to metalearning in the general response context of a discipline or subject. The development of metalearning capacity is framed within a protocol that invites students to self-construct…

  13. Wnt/Wingless Pathway Activation Is Promoted by a Critical Threshold of Axin Maintained by the Tumor Suppressor APC and the ADP-Ribose Polymerase Tankyrase.

    PubMed

    Wang, Zhenghan; Tacchelly-Benites, Ofelia; Yang, Eungi; Thorne, Curtis A; Nojima, Hisashi; Lee, Ethan; Ahmed, Yashi

    2016-05-01

    Wnt/β-catenin signal transduction directs metazoan development and is deregulated in numerous human congenital disorders and cancers. In the absence of Wnt stimulation, a multiprotein "destruction complex," assembled by the scaffold protein Axin, targets the key transcriptional activator β-catenin for proteolysis. Axin is maintained at very low levels that limit destruction complex activity, a property that is currently being exploited in the development of novel therapeutics for Wnt-driven cancers. Here, we use an in vivo approach in Drosophila to determine how tightly basal Axin levels must be controlled for Wnt/Wingless pathway activation, and how Axin stability is regulated. We find that for nearly all Wingless-driven developmental processes, a three- to fourfold increase in Axin is insufficient to inhibit signaling, setting a lower-limit for the threshold level of Axin in the majority of in vivo contexts. Further, we find that both the tumor suppressor adenomatous polyposis coli (APC) and the ADP-ribose polymerase Tankyrase (Tnks) have evolutionarily conserved roles in maintaining basal Axin levels below this in vivo threshold, and we define separable domains in Axin that are important for APC- or Tnks-dependent destabilization. Together, these findings reveal that both APC and Tnks maintain basal Axin levels below a critical in vivo threshold to promote robust pathway activation following Wnt stimulation. PMID:26975665

  14. Experimentally induced diabetes causes glial activation, glutamate toxicity and cellular damage leading to changes in motor function

    PubMed Central

    Nagayach, Aarti; Patro, Nisha; Patro, Ishan

    2014-01-01

    Behavioral impairments are the most empirical consequence of diabetes mellitus documented in both humans and animal models, but the underlying causes are still poorly understood. As the cerebellum plays a major role in coordination and execution of the motor functions, we investigated the possible involvement of glial activation, cellular degeneration and glutamate transportation in the cerebellum of rats, rendered diabetic by a single injection of streptozotocin (STZ; 45 mg/kg body weight; intraperitoneally). Motor function alterations were studied using Rotarod test (motor coordination) and grip strength (muscle activity) at 2nd, 4th, 6th, 8th, 10th, and 12th week post-diabetic confirmation. Scenario of glial (astroglia and microglia) activation, cell death and glutamate transportation was gaged using immunohistochemistry, histological study and image analysis. Cellular degeneration was clearly demarcated in the diabetic cerebellum. Glial cells were showing sequential and marked activation following diabetes in terms of both morphology and cell number. Bergmann glial cells were hypertrophied and distorted. Active caspase-3 positive apoptotic cells were profoundly present in all three cerebellar layers. Reduced co-labeling of GLT-1 and GFAP revealed the altered glutamate transportation in cerebellum following diabetes. These results, exclusively derived from histology, immunohistochemistry and cellular quantification, provide first insight over the associative reciprocity between the glial activation, cellular degeneration and reduced glutamate transportation, which presumably lead to the behavioral alterations following STZ-induced diabetes. PMID:25400546

  15. Pathophysiology of motor functions in prolonged manned space flights.

    PubMed

    Kozlovskaya, I B; Kreidich YuV; Oganov, V S; Koserenko, O P

    1981-01-01

    The influence of weightlessness on different parts of the motor system have been studied in crew members of 140 and 175 days space flights. It has been shown that weightlessness affects all parts of the motor system including (i) the leg and trunk muscles, in which severe atonia, a decrease of strength and an increase of electromyographic cost of contraction have been observed, (ii) the proprioceptive elements and the spinal reflex mechanisms in which decreased thresholds accompanied by decreases of maximal amplitude of reflexes and disturbances in cross reflex mechanisms have been found. and (iii) the central mechanisms that control characteristics of postural and locomotor activities. The intensities and durations of disturbances of different parts of the motor system did not correlate to each other, but did correlate with prophylactic activity during space flight. The data suggest a different nature of disturbances caused by weightlessness in different parts of the motor system. PMID:11543096

  16. The structural coupling between ATPase activation and recovery stroke in the myosin II motor

    SciTech Connect

    Koppole, Sampath; Smith, Jeremy C; Fischer, S.

    2007-07-01

    Before the myosin motor head can perform the next power stroke, it undergoes a large conformational transition in which the converter domain, bearing the lever arm, rotates {approx} 65{sup o}. Simultaneous with this 'recovery stroke', myosin activates its ATPase function by closing the Switch-2 loop over the bound ATP. This coupling between the motions of the converter domain and of the 40 {angstrom}-distant Switch-2 loop is essential to avoid unproductive ATP hydrolysis. The coupling mechanism is determined here by finding a series of optimized intermediates between crystallographic end structures of the recovery stroke (Dictyostelium discoideum), yielding movies of the transition at atomic detail. The successive formation of two hydrogen bonds by the Switch-2 loop is correlated with the successive see-saw motions of the relay and SH1 helices that hold the converter domain. SH1 helix and Switch-2 loop communicate via a highly conserved loop that wedges against the SH1-helix upon Switch-2 closing.

  17. Motor activity and mitotic spindle localization of the Drosophila kinesin-like protein KLP61F.

    PubMed Central

    Barton, N R; Pereira, A J; Goldstein, L S

    1995-01-01

    The KLP61F gene product is essential for Drosophila development. Mutations in KLP61F display a mitotic arrest phenotype caused by a failure in the proper separation of duplicated centrosomes (Heck et al., 1993). Sequence analysis of KLP61F identified it as a member of the bimC family of kinesin-like microtubule motor proteins. Here we report that KLP61F is distinct from KRP130, a kinesin-like protein recently purified from Drosophila embryos and suggested to be the product of the KLP61F gene (Cole et al., 1994). We also characterized recombinant KLP61F and found that it possesses microtubule-stimulated ATPase and microtubule translocation activities in vitro. In addition, we have used an affinity-purified, KLP61F-specific antiserum to localize native KLP61F and an epitope-tagged KLP61F fusion protein during various stages of mitosis in Drosophila syncytial blastoderm embryos. From early prophase through anaphase, KLP61F is coincident with the distribution of tubulin. Together these results confirm the existence of multiple bimC-like kinesins in Drosophila and suggest that KLP61F function is intrinsic to the mitotic spindle. Images PMID:8589456

  18. The influence of negative ionization of the air on motor activity in Syrian hamsters ( Masocricetus auratus Waterhouse) in light conditions

    NASA Astrophysics Data System (ADS)

    Lenkiewicz, Zofia; Dabrowska, Barbara; Schiffer, Zofia

    1989-12-01

    The motor activity of Syrian hamsters ( Mesocricetus auratus Waterhouse) under the influence of negative ionization of the atmosphere applied for 10, 20 or 30 min per day was investigated. An ionizer with output of 14000 light negative ions per 1 cm3 of air was used. Studies carried out in the light phase of a 12∶12 h light/dark regime revealed a relation between the reaction of the animal and the time of day at which ionization was applied. Ionization for 20 or 30 min in the light phase decreased motor activity, while 10 min of ionization increased it compared to control animals. Ionization in the dark phase gave a more distinct rise in activity than that applied in the light phase for all three durations of ionization.

  19. Behavioral and Neural Plasticity of Ocular Motor Control: Changes in Performance and fMRI Activity Following Antisaccade Training

    PubMed Central

    Jamadar, Sharna D.; Johnson, Beth P.; Clough, Meaghan; Egan, Gary F.; Fielding, Joanne

    2015-01-01

    The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. PMID:26733841

  20. Increased topographical variability of task-related activation in perceptive and motor associative regions in adult autistics

    PubMed Central

    Poulin-Lord, Marie-Pier; Barbeau, Elise B.; Soulières, Isabelle; Monchi, Oury; Doyon, Julien; Benali, Habib; Mottron, Laurent

    2014-01-01

    Background An enhanced plasticity is suspected to play a role in various microstructural alterations, as well as in regional cortical reallocations observed in autism. Combined with multiple indications of enhanced perceptual functioning in autism, and indications of atypical motor functioning, enhanced plasticity predicts a superior variability in functional cortical allocation, predominant in perceptual and motor regions. Method To test this prediction, we scanned 23 autistics and 22 typical participants matched on age, FSIQ, Raven percentile scores and handedness during a visuo-motor imitation task. For each participant, the coordinates of the strongest task-related activation peak were extracted in the primary (Brodmann area 4) and supplementary (BA 6) motor cortex, the visuomotor superior parietal cortex (BA 7), and the primary (BA 17) and associative (BAs 18 + 19) visual areas. Mean signal changes for each ROI in both hemispheres, and the number of voxels composing the strongest activation cluster were individually extracted to compare intensity and size of the signal between groups. For each ROI, in each hemisphere, and for every participant, the distance from their respective group average was used as a variable of interest to determine group differences in localization variability using repeated measures ANOVAs. Between-group comparison of whole-brain activation was also performed. Results Both groups displayed a higher mean variability in the localization of activations in the associative areas compared to the primary visual or motor areas. However, despite this shared increased variability in associative cortices, a direct between-group comparison of the individual variability in localization of the activation revealed a significantly greater variability in the autistic group than in the typical group in the left visuo-motor superior parietal cortex (BA 7) and in the left associative visual areas (BAs 18 + 19). Conclusion Different and possibly

  1. Numerical simulation on the adaptation of forms in trabecular bone to mechanical disuse and basic multi-cellular unit activation threshold at menopause

    NASA Astrophysics Data System (ADS)

    Gong, He; Fan, Yubo; Zhang, Ming

    2008-04-01

    The objective of this paper is to identify the effects of mechanical disuse and basic multi-cellular unit (BMU) activation threshold on the form of trabecular bone during menopause. A bone adaptation model with mechanical- biological factors at BMU level was integrated with finite element analysis to simulate the changes of trabecular bone structure during menopause. Mechanical disuse and changes in the BMU activation threshold were applied to the model for the period from 4 years before to 4 years after menopause. The changes in bone volume fraction, trabecular thickness and fractal dimension of the trabecular structures were used to quantify the changes of trabecular bone in three different cases associated with mechanical disuse and BMU activation threshold. It was found that the changes in the simulated bone volume fraction were highly correlated and consistent with clinical data, and that the trabecular thickness reduced significantly during menopause and was highly linearly correlated with the bone volume fraction, and that the change trend of fractal dimension of the simulated trabecular structure was in correspondence with clinical observations. The numerical simulation in this paper may help to better understand the relationship between the bone morphology and the mechanical, as well as biological environment; and can provide a quantitative computational model and methodology for the numerical simulation of the bone structural morphological changes caused by the mechanical environment, and/or the biological environment.

  2. PACAP27 prevents Parkinson-like neuronal loss and motor deficits but not microglia activation induced by prostaglandin J2.

    PubMed

    Shivers, Kai-Yvonne; Nikolopoulou, Anastasia; Machlovi, Saima Ishaq; Vallabhajosula, Shankar; Figueiredo-Pereira, Maria E

    2014-09-01

    Neuroinflammation is a major risk factor in Parkinson's disease (PD). Alternative approaches are needed to treat inflammation, as anti-inflammatory drugs such as NSAIDs that inhibit cyclooxygenase-2 (COX-2) can produce devastating side effects, including heart attack and stroke. New therapeutic strategies that target factors downstream of COX-2, such as prostaglandin J2 (PGJ2), hold tremendous promise because they will not alter the homeostatic balance offered by COX-2 derived prostanoids. In the current studies, we report that repeated microinfusion of PGJ2 into the substantia nigra of non-transgenic mice, induces three stages of pathology that mimic the slow-onset cellular and behavioral pathology of PD: mild (one injection) when only motor deficits are detectable, intermediate (two injections) when neuronal and motor deficits as well as microglia activation are detectable, and severe (four injections) when dopaminergic neuronal loss is massive accompanied by microglia activation and motor deficits. Microglia activation was evaluated in vivo by positron emission tomography (PET) with [(11)C](R)PK11195 to provide a regional estimation of brain inflammation. PACAP27 reduced dopaminergic neuronal loss and motor deficits induced by PGJ2, without preventing microglia activation. The latter could be problematic in that persistent microglia activation can exert long-term deleterious effects on neurons and behavior. In conclusion, this PGJ2-induced mouse model that mimics in part chronic inflammation, exhibits slow-onset PD-like pathology and is optimal for testing diagnostic tools such as PET, as well as therapies designed to target the integrated signaling across neurons and microglia, to fully benefit patients with PD. PMID:24970746

  3. PACAP27 prevents Parkinson-like neuronal loss and motor deficits but not microglia activation induced by prostaglandin J2

    PubMed Central

    Shivers, Kai-Yvonne; Nikolopoulou, Anastasia; Machlovi, Saima Ishaq; Vallabhajosula, Shankar; Figueiredo-Pereira, Maria E.

    2014-01-01

    Neuroinflammation is a major risk factor in Parkinson disease (PD). Alternative approaches are needed to treat inflammation, as anti-inflammatory drugs such as NSAIDs that inhibit cyclooxygenase-2 (COX-2) can produce devastating side effects, including heart attack and stroke. New therapeutic strategies that target factors downstream of COX-2, such as prostaglandin J2 (PGJ2), hold tremendous promise because they will not alter the homeostatic balance offered by COX-2 derived prostanoids. In the current studies, we report that repeated microinfusion of PGJ2 into the substantia nigra of non-transgenic mice, induces three stages of pathology that mimic the slow-onset cellular and behavioral pathology of PD: mild (one injection) when only motor deficits are detectable, intermediate (two injections) when neuronal and motor deficits as well as microglia activation are detectable, and severe (four injections) when dopaminergic neuronal loss is massive accompanied by microglia activation and motor deficits. Microglia activation was evaluated in vivo by positron emission tomography (PET) with [11C](R)PK11195 to provide a regional estimation of brain inflammation. PACAP27 reduced dopaminergic neuronal loss and motor deficits induced by PGJ2, without preventing microglia activation. The latter could be problematic in that persistent microglia activation can exert long-term deleterious effects on neurons and behavior. In conclusion, this PGJ2-induced mouse model that mimics in part chronic inflammation, exhibits slow-onset PD-like pathology and is optimal for testing diagnostic tools such as PET, as well as therapies designed to target the integrated signaling across neurons and microglia, to fully benefit patients with PD. PMID:24970746

  4. Serotonin 2A and 2B receptor-induced phrenic motor facilitation: differential requirement for spinal NADPH oxidase activity

    PubMed Central

    MacFarlane, P.M.; Vinit, S.; Mitchell, G.S.

    2011-01-01

    Acute intermittent hypoxia (AIH) facilitates phrenic motor output by a mechanism that requires spinal serotonin (type 2) receptor activation, NADPH oxidase activity and formation of reactive oxygen species (ROS). Episodic spinal serotonin (5-HT) receptor activation alone, without changes in oxygenation, is sufficient to elicit NADPH oxidase-dependent phrenic motor facilitation (pMF). Here we investigated: 1) whether serotonin 2A and/or 2B (5-HT2a/b) receptors are expressed in identified phrenic motor neurons, and 2) which receptor subtype is capable of eliciting NADPH-oxidase-dependent pMF. In anesthetized, artificially ventilated adult rats, episodic C4 intrathecal injections (3 × 6µl injections, 5 min intervals) of a 5-HT2a (DOI) or 5-HT2b (BW723C86) receptor agonist elicited progressive and sustained increases in integrated phrenic nerve burst amplitude (i.e. pMF), an effect lasting at least 90 minutes post-injection for both receptor subtypes. 5-HT2a and 5-HT2b receptor agonist-induced pMF were both blocked by selective antagonists (ketanserin and SB206553, respectively), but not by antagonists to the other receptor subtype. Single injections of either agonist failed to elicit pMF, demonstrating a need for episodic receptor activation. Phrenic motor neurons retrogradely labeled with cholera toxin B fragment expressed both 5-HT2a and 5-HT2b receptors. Pre-treatment with NADPH oxidase inhibitors (apocynin and DPI) blocked 5-HT2b, but not 5-HT2a-induced pMF. Thus, multiple spinal type 2 serotonin receptors elicit pMF, but they act via distinct mechanisms that differ in their requirement for NADPH oxidase activity. PMID:21223996

  5. Spontaneous motor seizures of rats with kainate-induced epilepsy: effect of time of day and activity state.

    PubMed

    Hellier, J L; Dudek, F E

    1999-05-01

    Kainate treatment in rats can result in a chronic behavioral state that is similar to human temporal lobe epilepsy. We tested the hypothesis that, like some humans with epilepsy, rat with kainate-induced epilepsy have more spontaneous motor seizures during inactivity (i.e. little to no volitional movement, including apparent sleep) than during activity (i.e. apparent volitional movement, as in walking, grooming, eating, etc.). Rats were given intraperitoneal (i.p.) injections of kainate (5 mg/kg) every hour so that class III/IV/V seizures were elicited for > or = 3 h. Seizure behavior was video-monitored (24 h for 5-6 days, n = 32 rats at 3 months and n = 23 rats at 4 months after treatment) to examine the occurrence of seizures as a function of light versus dark (12-12-h light-dark cycle) and inactivity versus activity. Significantly more spontaneous motor seizur