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Sample records for motor activity signals

  1. 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

  2. Useful signals from motor cortex

    PubMed Central

    Schwartz, Andrew B

    2007-01-01

    Historically, the motor cortical function has been explained as a funnel to muscle activation. This invokes the idea that motor cortical neurons, or ‘upper motoneurons’, directly cause muscle contraction just like spinal motoneurons. Thus, the motor cortex and muscle activity are inextricably entwined like a puppet master and his marionette. Recently, this concept has been challenged by current experimentation showing that many behavioural aspects of action are represented in motor cortical activity. Although this activity may still be related to muscle activation, the relation between the two is likely to be indirect and complex, whereas the relation between cortical activity and kinematic parameters is simple and robust. These findings show how to extract useful signals that help explain the underlying process that generates behaviour and to harness these signals for potentially therapeutic applications. PMID:17255162

  3. 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

  4. A simulated actuator driven by motor cortical signals.

    PubMed

    Lukashin, A V; Amirikian, B R; Georgopoulos, A P

    1996-11-01

    One problem in motor control concerns the mechanism whereby the central nervous system translates the motor cortical command encoded in cell activity into a coordinated contraction of limb muscles to generate a desired motor output. This problem is closely related to the design of adaptive systems that transform neuronal signals chronically recorded from the motor cortex into the physiologically appropriate motor output of multijoint prosthetic limbs. In this study we demonstrated how this transformation can be carried out by an artificial neural network using as command signals the actual impulse activity obtained from recordings in the motor cortex of monkeys during the performance of a task that required the exertion of force in different directions. The network receives experimentally measured brain signals and recodes them into motor actions of a simulated actuator that mimics the primate arm. The actuator responds to the motor cortical commands with surprising fidelity, generating forces in close quantitative agreement with those exerted by trained monkeys, in both the temporal and spatial domains. Moreover, we show that the time-varying motor output may be controlled by the impulse activity of as few as 15 motor cortical cells. These results outline a potentially implementable computation scheme that utilizes raw neuronal signals to drive artificial mechanical systems. PMID:8981430

  5. Activation of the pre-supplementary motor area but not inferior prefrontal cortex in association with short stop signal reaction time – an intra-subject analysis

    PubMed Central

    Chao, Herta HA; Luo, Xi; Chang, Jeremy LK; Li, Chiang-shan R

    2009-01-01

    Background Our previous work described the neural processes of motor response inhibition during a stop signal task (SST). Employing the race model, we computed the stop signal reaction time (SSRT) to index individuals' ability in inhibitory control. The pre-supplementary motor area (preSMA), which shows greater activity in individuals with short as compared to those with long SSRT, plays a role in mediating response inhibition. In contrast, the right inferior prefrontal cortex (rIFC) showed greater activity during stop success as compared to stop error. Here we further pursued this functional differentiation of preSMA and rIFC on the basis of an intra-subject approach. Results Of 65 subjects who participated in four sessions of the SST, we identified 30 individuals who showed a difference in SSRT but were identical in other aspects of stop signal performance between the first ("early") and last two ("late") sessions. By comparing regional brain activation between the two sessions, we confirmed greater preSMA but not rIFC activity during short as compared to long SSRT session within individuals. Furthermore, putamen, anterior cerebellum and middle/posterior cingulate cortex also showed greater activity in association with short SSRT. Conclusion These results are consistent with a role of medial prefrontal cortex in controlled action and inferior frontal cortex in orienting attention. We discussed these findings with respect to the process of attentional monitoring and inhibitory motor control during stop signal inhibition. PMID:19602259

  6. Noradrenergic modulation of masseter muscle activity during natural rapid eye movement sleep requires glutamatergic signalling at the trigeminal motor nucleus.

    PubMed

    Schwarz, Peter B; Mir, Saba; Peever, John H

    2014-08-15

    Noradrenergic neurotransmission in the brainstem is closely coupled to changes in muscle activity across the sleep-wake cycle, and noradrenaline is considered to be a key excitatory neuromodulator that reinforces the arousal-related stimulus on motoneurons to drive movement. However, it is unknown if α-1 noradrenoceptor activation increases motoneuron responsiveness to excitatory glutamate (AMPA) receptor-mediated inputs during natural behaviour. We studied the effects of noradrenaline on AMPA receptor-mediated motor activity at the motoneuron level in freely behaving rats, particularly during rapid eye movement (REM) sleep, a period during which both AMPA receptor-triggered muscle twitches and periods of muscle quiescence in which AMPA drive is silent are exhibited. Male rats were subjected to electromyography and electroencephalography recording to monitor sleep and waking behaviour. The implantation of a cannula into the trigeminal motor nucleus of the brainstem allowed us to perfuse noradrenergic and glutamatergic drugs by reverse microdialysis, and thus to use masseter muscle activity as an index of motoneuronal output. We found that endogenous excitation of both α-1 noradrenoceptor and AMPA receptors during waking are coupled to motor activity; however, REM sleep exhibits an absence of endogenous α-1 noradrenoceptor activity. Importantly, exogenous α-1 noradrenoceptor stimulation cannot reverse the muscle twitch suppression induced by AMPA receptor blockade and nor can it elevate muscle activity during quiet REM, a phase when endogenous AMPA receptor activity is subthreshold. We conclude that the presence of an endogenous glutamatergic drive is necessary for noradrenaline to trigger muscle activity at the level of the motoneuron in an animal behaving naturally. PMID:24860176

  7. LRRK2 overexpression alters glutamatergic presynaptic plasticity, striatal dopamine tone, postsynaptic signal transduction, motor activity and memory.

    PubMed

    Beccano-Kelly, Dayne A; Volta, Mattia; Munsie, Lise N; Paschall, Sarah A; Tatarnikov, Igor; Co, Kimberley; Chou, Patrick; Cao, Li-Ping; Bergeron, Sabrina; Mitchell, Emma; Han, Heather; Melrose, Heather L; Tapia, Lucia; Raymond, Lynn A; Farrer, Matthew J; Milnerwood, Austen J

    2015-03-01

    Mutations in leucine-rich repeat kinase 2 (Lrrk2) are the most common genetic cause of Parkinson's disease (PD), a neurodegenerative disorder affecting 1-2% of those >65 years old. The neurophysiology of LRRK2 remains largely elusive, although protein loss suggests a role in glutamatergic synapse transmission and overexpression studies show altered dopamine release in aged mice. We show that glutamate transmission is unaltered onto striatal projection neurons (SPNs) of adult LRRK2 knockout mice and that adult animals exhibit no detectable cognitive or motor deficits. Basal synaptic transmission is also unaltered in SPNs of LRRK2 overexpressing mice, but they do exhibit clear alterations to D2-receptor-mediated short-term synaptic plasticity, behavioral hypoactivity and impaired recognition memory. These phenomena are associated with decreased striatal dopamine tone and abnormal dopamine- and cAMP-regulated phosphoprotein 32 kDa signal integration. The data suggest that LRRK2 acts at the nexus of dopamine and glutamate signaling in the adult striatum, where it regulates dopamine levels, presynaptic glutamate release via D2-dependent synaptic plasticity and dopamine-receptor signal transduction. PMID:25343991

  8. 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.

  9. Decoding 3D reach and grasp from hybrid signals in motor and premotor cortices: spikes, multiunit activity, and local field potentials

    PubMed Central

    Truccolo, Wilson; Vargas-Irwin, Carlos E.; Donoghue, John P.

    2012-01-01

    Neural activity in motor cortex during reach and grasp movements shows modulations in a broad range of signals from single-neuron spiking activity (SA) to various frequency bands in broadband local field potentials (LFPs). In particular, spatiotemporal patterns in multiband LFPs are thought to reflect dendritic integration of local and interareal synaptic inputs, attentional and preparatory processes, and multiunit activity (MUA) related to movement representation in the local motor area. Nevertheless, the relationship between multiband LFPs and SA, and their relationship to movement parameters and their relative value as brain-computer interface (BCI) control signals, remain poorly understood. Also, although this broad range of signals may provide complementary information channels in primary (MI) and ventral premotor (PMv) areas, areal differences in information have not been systematically examined. Here, for the first time, the amount of information in SA and multiband LFPs was compared for MI and PMv by recording from dual 96-multielectrode arrays while monkeys made naturalistic reach and grasp actions. Information was assessed as decoding accuracy for 3D arm end point and grip aperture kinematics based on SA or LFPs in MI and PMv, or combinations of signal types across areas. In contrast with previous studies with ≤16 simultaneous electrodes, here ensembles of >16 units (on average) carried more information than multiband, multichannel LFPs. Furthermore, reach and grasp information added by various LFP frequency bands was not independent from that in SA ensembles but rather typically less than and primarily contained within the latter. Notably, MI and PMv did not show a particular bias toward reach or grasp for this task or for a broad range of signal types. For BCIs, our results indicate that neuronal ensemble spiking is the preferred signal for decoding, while LFPs and combined signals from PMv and MI can add robustness to BCI control. PMID:22157115

  10. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  11. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  12. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  13. Enhanced Muscle Afferent Signals during Motor Learning in Humans.

    PubMed

    Dimitriou, Michael

    2016-04-25

    Much has been revealed concerning human motor learning at the behavioral level [1, 2], but less is known about changes in the involved neural circuits and signals. By examining muscle spindle responses during a classic visuomotor adaptation task [3-6] performed by fully alert humans, I found substantial modulation of sensory afferent signals as a function of adaptation state. Specifically, spindle control was independent of concurrent muscle activity but was specific to movement direction (representing muscle lengthening versus shortening) and to different stages of learning. Increased spindle afferent responses to muscle stretch occurring early during learning reflected individual error size and were negatively related to subsequent antagonist activity (i.e., 60-80 ms thereafter). Relative increases in tonic afferent output early during learning were predictive of the subjects' adaptation rate. I also found that independent spindle control during sensory realignment (the "washout" stage) induced afferent signal "linearization" with respect to muscle length (i.e., signals were more tuned to hand position). The results demonstrate for the first time that motor learning also involves independent and state-related modulation of sensory mechanoreceptor signals. The current findings suggest that adaptive motor performance also relies on the independent control of sensors, not just of muscles. I propose that the "γ" motor system innervating spindles acts to facilitate the acquisition and extraction of task-relevant information at the early stages of sensorimotor adaptation. This designates a more active and targeted role for the human proprioceptive system during motor learning. PMID:27040776

  14. 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

  15. 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

  16. Gating of neural error signals during motor learning

    PubMed Central

    Kimpo, Rhea R; Rinaldi, Jacob M; Kim, Christina K; Payne, Hannah L; Raymond, Jennifer L

    2014-01-01

    Cerebellar climbing fiber activity encodes performance errors during many motor learning tasks, but the role of these error signals in learning has been controversial. We compared two motor learning paradigms that elicited equally robust putative error signals in the same climbing fibers: learned increases and decreases in the gain of the vestibulo-ocular reflex (VOR). During VOR-increase training, climbing fiber activity on one trial predicted changes in cerebellar output on the next trial, and optogenetic activation of climbing fibers to mimic their encoding of performance errors was sufficient to implant a motor memory. In contrast, during VOR-decrease training, there was no trial-by-trial correlation between climbing fiber activity and changes in cerebellar output, and climbing fiber activation did not induce VOR-decrease learning. Our data suggest that the ability of climbing fibers to induce plasticity can be dynamically gated in vivo, even under conditions where climbing fibers are robustly activated by performance errors. DOI: http://dx.doi.org/10.7554/eLife.02076.001 PMID:24755290

  17. Signal focusing through active transport

    NASA Astrophysics Data System (ADS)

    Godec, Aljaž; Metzler, Ralf

    2015-07-01

    The accuracy of molecular signaling in biological cells and novel diagnostic devices is ultimately limited by the counting noise floor imposed by the thermal diffusion. Motivated by the fact that messenger RNA and vesicle-engulfed signaling molecules transiently bind to molecular motors and are actively transported in biological cells, we show here that the random active delivery of signaling particles to within a typical diffusion distance to the receptor generically reduces the correlation time of the counting noise. Considering a variety of signaling particle sizes from mRNA to vesicles and cell sizes from prokaryotic to eukaryotic cells, we show that the conditions for active focusing—faster and more precise signaling—are indeed compatible with observations in living cells. Our results improve the understanding of molecular cellular signaling and novel diagnostic devices.

  18. Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals

    PubMed Central

    Batres-Mendoza, Patricia; Montoro-Sanjose, Carlos R.; Guerra-Hernandez, Erick I.; Almanza-Ojeda, Dora L.; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene J.; Ibarra-Manzano, Mario A.

    2016-01-01

    Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG) signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA) to represent EEG signals obtained using a brain-computer interface (BCI) device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT), support vector machine (SVM) and k-nearest neighbor (KNN) techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states. PMID:26959029

  19. Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals.

    PubMed

    Batres-Mendoza, Patricia; Montoro-Sanjose, Carlos R; Guerra-Hernandez, Erick I; Almanza-Ojeda, Dora L; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene J; Ibarra-Manzano, Mario A

    2016-01-01

    Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG) signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA) to represent EEG signals obtained using a brain-computer interface (BCI) device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT), support vector machine (SVM) and k-nearest neighbor (KNN) techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states. PMID:26959029

  20. Iterative Role of Notch Signaling in Spinal Motor Neuron Diversification.

    PubMed

    Tan, G Christopher; Mazzoni, Esteban O; Wichterle, Hynek

    2016-07-26

    The motor neuron progenitor domain in the ventral spinal cord gives rise to multiple subtypes of motor neurons and glial cells. Here, we examine whether progenitors found in this domain are multipotent and which signals contribute to their cell-type-specific differentiation. Using an in vitro neural differentiation model, we demonstrate that motor neuron progenitor differentiation is iteratively controlled by Notch signaling. First, Notch controls the timing of motor neuron genesis by repressing Neurogenin 2 (Ngn2) and maintaining Olig2-positive progenitors in a proliferative state. Second, in an Ngn2-independent manner, Notch contributes to the specification of median versus hypaxial motor column identity and lateral versus medial divisional identity of limb-innervating motor neurons. Thus, motor neuron progenitors are multipotent, and their diversification is controlled by Notch signaling that iteratively increases cellular diversity arising from a single neural progenitor domain. PMID:27425621

  1. 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

  2. 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

  3. 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

  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. Monitoring Local Regional Hemodynamic Signal Changes during Motor Execution and Motor Imagery Using Near-Infrared Spectroscopy

    PubMed Central

    Iso, Naoki; Moriuchi, Takefumi; Sagari, Akira; Kitajima, Eiji; Iso, Fumiko; Tanaka, Koji; Kikuchi, Yasuki; Tabira, Takayuki; Higashi, Toshio

    2016-01-01

    The aim of this study was to clarify the topographical localization of motor-related regional hemodynamic signal changes during motor execution (ME) and motor imagery (MI) by using near-infrared spectroscopy (NIRS), as this technique is more clinically expedient than established methods (e.g., fMRI). Twenty right-handed healthy subjects participated in this study. The experimental protocol was a blocked design consisting of 3 cycles of 20 s of task performance and 30 s of rest. The tapping sequence task was performed with their fingers under 4 conditions: ME and MI with the right or left hand. Hemodynamic brain activity was measured with NIRS to monitor changes in oxygenated hemoglobin (oxy-Hb) concentration. Oxy-Hb in the somatosensory motor cortex (SMC) increased significantly only during contralateral ME and showed a significant interaction between task and hand. There was a main effect of hand in the left SMC. Although there were no significant main effects or interactions in the supplemental motor area (SMA) and premotor area (PMA), oxy-Hb increased substantially under all conditions. These results clarified the topographical localization by motor-related regional hemodynamic signal changes during ME and MI by using NIRS. PMID:26793118

  6. 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

  7. 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

  8. Application of signal detection theory to perceptual-motor skills.

    PubMed

    Jagacinski, R J; Isaac, P D; Burke, M W

    1977-09-01

    A signal-detection paradigm was utilized to examine subjects' sensitivity to situational and sensory-motor stimuli in predicting motor skill performance. College-level and professional basketball players attempted uncontested shots from assigned positions on the basketball court. Before each shot was released, both the shooter and a passive observer were required to predict whether it would be successful. Signal-detection analysis revealed no evidence for greater sensitivity of the shooter over the passive observer or an idealized statistical predictor using only floor position as a prediction cue. Both shooters and passive observers were too optimistic when strong penalties were imposed for incorrect predictions of success. PMID:23952878

  9. Error Signals in Motor Cortices Drive Adaptation in Reaching.

    PubMed

    Inoue, Masato; Uchimura, Motoaki; Kitazawa, Shigeru

    2016-06-01

    Reaching movements are subject to adaptation in response to errors induced by prisms or external perturbations. Motor cortical circuits have been hypothesized to provide execution errors that drive adaptation, but human imaging studies to date have reported that execution errors are encoded in parietal association areas. Thus, little evidence has been uncovered that supports the motor hypothesis. Here, we show that both primary motor and premotor cortices encode information on end-point errors in reaching. We further show that post-movement microstimulation to these regions caused trial-by-trial increases in errors, which subsided exponentially when the stimulation was terminated. The results indicate for the first time that motor cortical circuits provide error signals that drive trial-by-trial adaptation in reaching movements. PMID:27181058

  10. Signal differentiation in position tracking control of dc motors

    NASA Astrophysics Data System (ADS)

    Beltran-Carbajal, F.; Valderrabano-Gonzalez, A.; Rosas-Caro, J. C.

    2015-01-01

    An asymptotic differentiation approach with respect to time is used for on-line estimation of velocity and acceleration signals in controlled dc motors. The attractive feature of this differentiator of signals is that it does not require any system mathematical model, which allows its use in engineering systems that require the signal differentiation for its control, identification, fault detection, among other applications. Moreover, it is shown that the differentiation approach can be applied for output signals showing a chaotic behavior. In addition a differential flatness control scheme with additional integral compensation of the output error is proposed for tracking tasks of position reference trajectories for direct current electric motors using angular position measurements only.

  11. Condition monitoring of gearboxes using synchronously averaged electric motor signals

    NASA Astrophysics Data System (ADS)

    Ottewill, J. R.; Orkisz, M.

    2013-07-01

    Due to their prevalence in rotating machinery, the condition monitoring of gearboxes is extremely important in the minimization of potentially dangerous and expensive failures. Traditionally, gearbox condition monitoring has been conducted using measurements obtained from casing-mounted vibration transducers such as accelerometers. A well-established technique for analyzing such signals is the synchronous signal average, where vibration signals are synchronized to a measured angular position and then averaged from rotation to rotation. Driven, in part, by improvements in control methodologies based upon methods of estimating rotor speed and torque, induction machines are used increasingly in industry to drive rotating machinery. As a result, attempts have been made to diagnose defects using measured terminal currents and voltages. In this paper, the application of the synchronous signal averaging methodology to electric drive signals, by synchronizing stator current signals with a shaft position estimated from current and voltage measurements is proposed. Initially, a test-rig is introduced based on an induction motor driving a two-stage reduction gearbox which is loaded by a DC motor. It is shown that a defect seeded into the gearbox may be located using signals acquired from casing-mounted accelerometers and shaft mounted encoders. Using simple models of an induction motor and a gearbox, it is shown that it should be possible to observe gearbox defects in the measured stator current signal. A robust method of extracting the average speed of a machine from the current frequency spectrum, based on the location of sidebands of the power supply frequency due to rotor eccentricity, is presented. The synchronous signal averaging method is applied to the resulting estimations of rotor position and torsional vibration. Experimental results show that the method is extremely adept at locating gear tooth defects. Further results, considering different loads and different

  12. Interference in Ballistic Motor Learning: Specificity and Role of Sensory Error Signals

    PubMed Central

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C.; Nielsen, Jens Bo

    2011-01-01

    Humans are capable of learning numerous motor skills, but newly acquired skills may be abolished by subsequent learning. Here we ask what factors determine whether interference occurs in motor learning. We speculated that interference requires competing processes of synaptic plasticity in overlapping circuits and predicted specificity. To test this, subjects learned a ballistic motor task. Interference was observed following subsequent learning of an accuracy-tracking task, but only if the competing task involved the same muscles and movement direction. Interference was not observed from a non-learning task suggesting that interference requires competing learning. Subsequent learning of the competing task 4 h after initial learning did not cause interference suggesting disruption of early motor memory consolidation as one possible mechanism underlying interference. Repeated transcranial magnetic stimulation (rTMS) of corticospinal motor output at intensities below movement threshold did not cause interference, whereas suprathreshold rTMS evoking motor responses and (re)afferent activation did. Finally, the experiments revealed that suprathreshold repetitive electrical stimulation of the agonist (but not antagonist) peripheral nerve caused interference. The present study is, to our knowledge, the first to demonstrate that peripheral nerve stimulation may cause interference. The finding underscores the importance of sensory feedback as error signals in motor learning. We conclude that interference requires competing plasticity in overlapping circuits. Interference is remarkably specific for circuits involved in a specific movement and it may relate to sensory error signals. PMID:21408054

  13. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Emergency signals; stopped commercial motor...) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS DRIVING OF COMMERCIAL MOTOR VEHICLES Stopped Commercial Motor Vehicles § 392.22 Emergency...

  14. Signals from the ventrolateral thalamus to the motor cortex during locomotion

    PubMed Central

    Marlinski, Vladimir; Nilaweera, Wijitha U.; Zelenin, Pavel V.; Sirota, Mikhail G.

    2012-01-01

    The activity of the motor cortex during locomotion is profoundly modulated in the rhythm of strides. The source of modulation is not known. In this study we examined the activity of one of the major sources of afferent input to the motor cortex, the ventrolateral thalamus (VL). Experiments were conducted in chronically implanted cats with an extracellular single-neuron recording technique. VL neurons projecting to the motor cortex were identified by antidromic responses. During locomotion, the activity of 92% of neurons was modulated in the rhythm of strides; 67% of cells discharged one activity burst per stride, a pattern typical for the motor cortex. The characteristics of these discharges in most VL neurons appeared to be well suited to contribute to the locomotion-related activity of the motor cortex. In addition to simple locomotion, we examined VL activity during walking on a horizontal ladder, a task that requires vision for correct foot placement. Upon transition from simple to ladder locomotion, the activity of most VL neurons exhibited the same changes that have been reported for the motor cortex, i.e., an increase in the strength of stride-related modulation and shortening of the discharge duration. Five modes of integration of simple and ladder locomotion-related information were recognized in the VL. We suggest that, in addition to contributing to the locomotion-related activity in the motor cortex during simple locomotion, the VL integrates and transmits signals needed for correct foot placement on a complex terrain to the motor cortex. PMID:21994259

  15. Chaos and Fractal Analysis of Electroencephalogram Signals during Different Imaginary Motor Movement Tasks

    NASA Astrophysics Data System (ADS)

    Soe, Ni Ni; Nakagawa, Masahiro

    2008-04-01

    This paper presents the novel approach to evaluate the effects of different motor activation tasks of the human electroencephalogram (EEG). The applications of chaos and fractal properties that are the most important tools in nonlinear analysis are been presented for four tasks of EEG during the real and imaginary motor movement. Three subjects, aged 23-30 years, participated in the experiment. Correlation dimension (D2), Lyapunov spectrum (λi), and Lyapunov dimension (DL) are been estimated to characterize the movement related EEG signals. Experimental results show that these nonlinear measures are good discriminators of EEG signals. There are significant differences in all conditions of subjective task. The fractal dimension appeared to be higher in movement conditions compared to the baseline condition. It is concluded that chaos and fractal analysis could be powerful methods in investigating brain activities during motor movements.

  16. Age-dependent changes of the antioxidant system in rat livers are accompanied by altered MAPK activation and a decline in motor signaling

    PubMed Central

    Yang, Wei; Burkhardt, Britta; Fischer, Luise; Beirow, Maja; Bork, Nadja; Wönne, Eva C.; Wagner, Cornelia; Husen, Bettina; Zeilinger, Katrin; Liu, Liegang; Nussler, Andreas K.

    2015-01-01

    Aging is characterized by a progressive decrease of cellular functions, because cells gradually lose their capacity to respond to injury. Increased oxidative stress is considered to be one of the major contributors to age-related changes in all organs including the liver. Our study has focused on elucidating whether important antioxidative enzymes, the mTOR pathway, and MAPKs exhibit age-dependent changes in the liver of rats during aging. We found an age-dependent increase of GSH in the cytosol and mitochondria. The aged liver showed an increased SOD enzyme activity, while the CAT enzyme activity decreased. HO-1 and NOS-2 gene expression was lower in adult rats, but up-regulated in aged rats. Western blot analysis revealed that SOD1, SOD2, GPx, GR, γ-GCL, and GSS were age-dependent up-regulated, while CAT remained constant. We also demonstrated that the phosphorylation of Akt, JNK, p38, and TSC2Ser1254 decreased while ERK1/2 and TSC2Thr1462 increased age-dependently. Furthermore, our data show that the mTOR pathway seems to be activated in livers of aged rats, and hence stimulating cell proliferation/regeneration, as confirmed by an age-dependent increase of PCNA and p-eIF4ESer209 protein expression. Our data may help to explain the fact that liver cells only proliferate in cases of necessity, like injury and damage. In summary, we have demonstrated that, age-dependent changes of the antioxidant system and stress-related signaling pathways occur in the livers of rats, which may help to better understand organ aging. PMID:27004051

  17. Diagnostics of DC and Induction Motors Based on the Analysis of Acoustic Signals

    NASA Astrophysics Data System (ADS)

    Glowacz, A.

    2014-10-01

    In this paper, a non-invasive method of early fault diagnostics of electric motors was proposed. This method uses acoustic signals generated by electric motors. Essential features were extracted from acoustic signals of motors. A plan of study of acoustic signals of electric motors was proposed. Researches were carried out for faultless induction motor, induction motor with one faulty rotor bar, induction motor with two faulty rotor bars and flawless Direct Current, and Direct Current motor with shorted rotor coils. Researches were carried out for methods of signal processing: log area ratio coefficients, Multiple signal classification, Nearest Neighbor classifier and the Bayes classifier. A pattern creation process was carried out using 40 samples of sound. In the identification process 130 five-second test samples were used. The proposed approach will also reduce the costs of maintenance and the number of faulty motors in the industry.

  18. 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…

  19. [Quality of neuronal signal registered in the monkey motor cortex with chronically implanted multiple microwires].

    PubMed

    Bondar', I V; Vasil'eva, L N; Badakva, A M; Miller, N V; Zobova, L N; Roshchin, V Iu

    2014-01-01

    Disconnection of central and peripheral parts of motor system leads to severe forms of disability. However, current research of brain-computer interfaces will solve the problem of rehabilitation of patients with motor disorders in future. Chronic recordings of single-unit activity in specialized areas of cerebral cortex could provide appropriate control signal for effectors with multiple degrees of freedom. In present article we evaluated the quality of chronic single-unit recordings in the primary motor cortex of awake behaving monkeys obtained with bundles of multiple microwires. Action potentials of proper quality were recorded from single units during three months. In some cases up to 7 single units could be extracted on a channel. Recording quality stabilized after 40 days since electrodes were implanted. Ultimately, functionality of multiple electrodes bundle makes it highly usable and reliable instrument for obtaining of control neurophysiologic signal from populations of neurons for brain-computer interfaces. PMID:25710068

  20. Drosophila motor neuron retraction during metamorphosis is mediated by inputs from TGF-β/BMP signaling and orphan nuclear receptors.

    PubMed

    Boulanger, Ana; Farge, Morgane; Ramanoudjame, Christophe; Wharton, Kristi; Dura, Jean-Maurice

    2012-01-01

    Larval motor neurons remodel during Drosophila neuro-muscular junction dismantling at metamorphosis. In this study, we describe the motor neuron retraction as opposed to degeneration based on the early disappearance of β-Spectrin and the continuing presence of Tubulin. By blocking cell dynamics with a dominant-negative form of Dynamin, we show that phagocytes have a key role in this process. Importantly, we show the presence of peripheral glial cells close to the neuro-muscular junction that retracts before the motor neuron. We show also that in muscle, expression of EcR-B1 encoding the steroid hormone receptor required for postsynaptic dismantling, is under the control of the ftz-f1/Hr39 orphan nuclear receptor pathway but not the TGF-β signaling pathway. In the motor neuron, activation of EcR-B1 expression by the two parallel pathways (TGF-β signaling and nuclear receptor) triggers axon retraction. We propose that a signal from a TGF-β family ligand is produced by the dismantling muscle (postsynapse compartment) and received by the motor neuron (presynaptic compartment) resulting in motor neuron retraction. The requirement of the two pathways in the motor neuron provides a molecular explanation for the instructive role of the postsynapse degradation on motor neuron retraction. This mechanism insures the temporality of the two processes and prevents motor neuron pruning before postsynaptic degradation. PMID:22792255

  1. Variation, Signal, and Noise in Cerebellar Sensory–Motor Processing for Smooth-Pursuit Eye Movements

    PubMed Central

    Medina, Javier F.; Lisberger, Stephen G.

    2009-01-01

    Neural responses are variable, yet motor performance can be quite precise. To ask how neural signal and noise are processed in the brain during sensory–motor behavior, we have evaluated the trial-by-trial variation of Purkinje cell (PC) activity in the floccular complex of the cerebellum, an intermediate stage in the neural circuit for smooth-pursuit eye movements. We find strong correlations between small trial-by-trial variations in the simple spike activity of individual PCs and the eye movements at the initiation of pursuit. The correlation is lower but still present during steady-state pursuit. Recordings from a few pairs of PCs verified the predictions of a model of the PC population, that there is a transition from highly covariant PC activity during movement initiation to more independent activity later on. Application to the data of a theoretical and computational analysis suggests that variation in pursuit initiation arises mostly from variation in visual motion signals that provide common inputs to the PC population. Variation in eye movement during steady-state pursuit can be attributed primarily to signal-dependent motor noise that arises downstream from PCs. PMID:17581971

  2. Spinal 5-HT7 receptors induce phrenic motor facilitation via EPAC-mTORC1 signaling.

    PubMed

    Fields, D P; Springborn, S R; Mitchell, G S

    2015-09-01

    Spinal serotonin type 7 (5-HT7) receptors elicit complex effects on motor activity. Whereas 5-HT7 receptor activation gives rise to long-lasting phrenic motor facilitation (pMF), it also constrains 5-HT2 receptor-induced pMF via "cross-talk inhibition." We hypothesized that divergent cAMP-dependent signaling pathways give rise to these distinct 5-HT7 receptor actions. Specifically, we hypothesized that protein kinase A (PKA) mediates cross-talk inhibition of 5-HT2 receptor-induced pMF whereas 5-HT7 receptor-induced pMF results from exchange protein activated by cAMP (EPAC) signaling. Anesthetized, paralyzed, and ventilated rats receiving intrathecal (C4) 5-HT7 receptor agonist (AS-19) injections expressed pMF for >90 min, an effect abolished by pretreatment with a selective EPAC inhibitor (ESI-05) but not a selective PKA inhibitor (KT-5720). Furthermore, intrathecal injections of a selective EPAC activator (8-pCPT-2'-Me-cAMP) were sufficient to elicit pMF. Finally, spinal mammalian target of rapamycin complex-1 (mTORC1) inhibition via intrathecal rapamycin abolished 5-HT7 receptor- and EPAC-induced pMF, demonstrating that spinal 5-HT7 receptors elicit pMF by an EPAC-mTORC1 signaling pathway. Thus 5-HT7 receptors elicit and constrain spinal phrenic motor plasticity via distinct signaling mechanisms that diverge at cAMP (EPAC vs. PKA). Selective manipulation of these molecules may enable refined regulation of serotonin-dependent spinal motor plasticity for therapeutic advantage. PMID:26269554

  3. 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…

  4. 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...

  5. 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

  6. 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

  7. Using ipsilateral motor signals in the unaffected cerebral hemisphere as a signal platform for brain-computer interfaces in hemiplegic stroke survivors

    NASA Astrophysics Data System (ADS)

    Bundy, David T.; Wronkiewicz, Mark; Sharma, Mohit; Moran, Daniel W.; Corbetta, Maurizio; Leuthardt, Eric C.

    2012-06-01

    Brain-computer interface (BCI) systems have emerged as a method to restore function and enhance communication in motor impaired patients. To date, this has been applied primarily to patients who have a compromised motor outflow due to spinal cord dysfunction, but an intact and functioning cerebral cortex. The cortical physiology associated with movement of the contralateral limb has typically been the signal substrate that has been used as a control signal. While this is an ideal control platform in patients with an intact motor cortex, these signals are lost after a hemispheric stroke. Thus, a different control signal is needed that could provide control capability for a patient with a hemiparetic limb. Previous studies have shown that there is a distinct cortical physiology associated with ipsilateral, or same-sided, limb movements. Thus far, it was unknown whether stroke survivors could intentionally and effectively modulate this ipsilateral motor activity from their unaffected hemisphere. Therefore, this study seeks to evaluate whether stroke survivors could effectively utilize ipsilateral motor activity from their unaffected hemisphere to achieve this BCI control. To investigate this possibility, electroencephalographic (EEG) signals were recorded from four chronic hemispheric stroke patients as they performed (or attempted to perform) real and imagined hand tasks using either their affected or unaffected hand. Following performance of the screening task, the ability of patients to utilize a BCI system was investigated during on-line control of a one-dimensional control task. Significant ipsilateral motor signals (associated with movement intentions of the affected hand) in the unaffected hemisphere, which were found to be distinct from rest and contralateral signals, were identified and subsequently used for a simple online BCI control task. We demonstrate here for the first time that EEG signals from the unaffected hemisphere, associated with overt and

  8. Using Ipsilateral Motor Signals in the Unaffected Cerebral Hemisphere as a Signal Platform for Brain Computer Interfaces in Hemiplegic Stroke Survivors

    PubMed Central

    Bundy, David T.; Wronkiewicz, Mark; Sharma, Mohit; Moran, Daniel W.; Corbetta, Maurizio; Leuthardt, Eric C.

    2012-01-01

    Objective Brain computer interface (BCI) systems have emerged as a method to restore function and enhance communication in motor impaired patients. To date, this has been primarily applied to patients who have a compromised motor outflow due to spinal cord dysfunction, but an intact and functioning cerebral cortex. The cortical physiology associated with movement of the contralateral limb has typically been the signal substrate that has been used as a control signal. While this is an ideal control platform in patients with an intact motor cortex, these signals are lost after a hemispheric stroke. Thus, a different control signal is needed that could provide control capability for a patient with a hemiparetic limb. Previous studies have shown that there is a distinct cortical physiology associated with ipsilateral, or same sided, limb movements. Thus far, it was unknown whether stroke survivors could intentionally and effectively modulate this ipsilateral motor activity from their unaffected hemisphere. Therefore, this study seeks to evaluate whether stroke survivors could effectively utilize ipsilateral motor activity from their unaffected hemisphere to achieve this BCI control. Approach To investigate this possibility, electroencephalographic (EEG) signals were recorded from four chronic hemispheric stroke patients as they performed (or attempted to perform) real and imagined hand tasks using either their affected or unaffected hand. Following performance of the screening task, the ability of patients to utilize a BCI system was investigated during on-line control of a 1-dimensional control task. Main Results Significant ipsilateral motor signals (associated with movement intentions of the affected hand) in the unaffected hemisphere, which were found to be distinct from rest and contralateral signals, were identified and subsequently used for a simple online BCI control task. We demonstrate here for the first time that EEG signals from the unaffected hemisphere

  9. 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

  10. Costal2 Functions as a Microtubule-Dependent Motor in the Hedgehog Signal Transduction Pathway

    PubMed Central

    Farzan, Shohreh F.; Ascano, Manuel; Ogden, Stacey K.; Sanial, Matthieu; Brigui, Amira; Plessis, Anne; Robbins, David J.

    2009-01-01

    SUMMARY The Hedgehog (Hh) signaling pathway initiates an evolutionarily conserved developmental program required for the proper patterning of many tissues. Costal2 (Cos2) is a requisite component of the Hh pathway, whose mechanistic role is not well understood. Cos2 was initially predicted, based on its primary sequence, to function as a microtubule-associated (MT) molecular motor. However, despite being identified over a decade ago, evidence showing that Cos2 function might require kinesin-like properties has for the most part been lacking. Thus the prevailing dogma in the field is that Cos2 functions solely as a scaffolding protein during Hh signal transduction. Here, we provide the first evidence that Cos2 motility is required for its biological function, and that this motility may be Hh regulated. We show that Cos2 motility requires an active motor domain, ATP and microtubules. Additionally, Cos2 recruits and transports other components of the Hh signaling pathway, including the transcription factor Cubitus interruptus (Ci), throughout the cell. Drosophila expressing cos2 mutations that encode proteins that lack motility are attenuated in their ability to regulate Ci activity and exhibit phenotypes consistent with attenuated Cos2 function. Combined, these results demonstrate that Cos2 motility plays an important role in its function, regulating the amounts and activity of Ci that ultimately interpret the level of Hh to which cells are exposed. PMID:18691888

  11. 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

  12. Stump nerve signals during transcranial magnetic motor cortex stimulation recorded in an amputee via longitudinal intrafascicular electrodes.

    PubMed

    Rossini, P M; Rigosa, Jacopo; Micera, Silvestro; Assenza, Giovanni; Rossini, Luca; Ferreri, Florinda

    2011-04-01

    Do central and peripheral motor pathways associated with an amputated limb retain at least some functions over periods of years? This problem could be addressed by evaluating the response patterns of nerve signals from peripheral motor fibers during transcranial magnetic stimulation (TMS) of corticospinal tracts. The aim of this study was to record for the first time TMS-related responses from the nerves of a left arm stump of an amputee via intrafascicular longitudinal flexible multi-electrodes (tfLIFE4) implanted for a prosthetic hand control. After tfLIFE4 implant in the stump median and ulnar nerves, TMS impulses of increasing intensity were delivered to the contralateral motor cortex while tfLIFE4 recordings were carried out. Combining TMS of increasing intensity and tfLIFE4 electrodes recordings, motor nerve activity possibly related to the missing limb motor control and selectively triggered by brain stimulation without significant electromyographic contamination was identified. These findings are entirely original and indicate that tfLIFE4 signals are clearly driven from M1 stimulation, therefore witnessing the presence in the stump nerves of viable motor signals from the CNS possibly useful for artificial prosthesis control. PMID:21390489

  13. 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

  14. Pedestrian signalization and the risk of pedestrian-motor vehicle collisions in Lima, Peru

    PubMed Central

    Quistberg, D. Alex; Koepsell, Thomas D.; Boyle, Linda Ng; Miranda, J. Jaime; Johnston, Brian D.; Ebel, Beth E.

    2014-01-01

    Safe walking environments are essential for protecting pedestrians and promoting physical activity. In Peru, pedestrians comprise of over three-quarters of road fatality victims. Pedestrian signalization plays an important role managing pedestrian and vehicle traffic and may help improve pedestrian safety. We examined the relationship between pedestrian-motor vehicle collisions and the presence of visible traffic signals, pedestrian signals, and signal timing to determine whether these countermeasures improved pedestrian safety. A matched case-control design was used where the units of study were crossing locations. We randomly sampled 97 control-matched collisions (weighted N=1134) at intersections occurring from October, 2010 to January, 2011 in Lima. Each case-control pair was matched on proximity, street classification, and number of lanes. Sites were visited between February, 2011 and September, 2011. Each analysis accounted for sampling weight and matching and was adjusted for vehicle and pedestrian traffic flow, crossing width, and mean vehicle speed. Collisions were more common where a phased pedestrian signal (green or red-lit signal) was present compared to no signalization (odds ratio [OR] 8.88, 95% Confidence Interval [CI] 1.32–59.6). A longer pedestrian-specific signal duration was associated with collision risk (OR 5.31, 95% CI 1.02–9.60 per 15-second interval). Collisions occurred more commonly in the presence of any signalization visible to pedestrians or pedestrian-specific signalization, though these associations were not statistically significant. Signalization efforts were not associated with lower risk for pedestrians; rather, they were associated with an increased risk of pedestrian-vehicle collisions. PMID:24821630

  15. Distinct roles for secreted semaphorin signaling in spinal motor axon guidance.

    PubMed

    Huber, Andrea B; Kania, Artur; Tran, Tracy S; Gu, Chenghua; De Marco Garcia, Natalia; Lieberam, Ivo; Johnson, Dontais; Jessell, Thomas M; Ginty, David D; Kolodkin, Alex L

    2005-12-22

    Neuropilins, secreted semaphorin coreceptors, are expressed in discrete populations of spinal motor neurons, suggesting they provide critical guidance information for the establishment of functional motor circuitry. We show here that motor axon growth and guidance are impaired in the absence of Sema3A-Npn-1 signaling. Motor axons enter the limb precociously, showing that Sema3A controls the timing of motor axon in-growth to the limb. Lateral motor column (LMC) motor axons within spinal nerves are defasciculated as they grow toward the limb and converge in the plexus region. Medial and lateral LMC motor axons show dorso-ventral guidance defects in the forelimb. In contrast, Sema3F-Npn-2 signaling guides the axons of a medial subset of LMC neurons to the ventral limb, but plays no major role in regulating their fasciculation. Thus, Sema3A-Npn-1 and Sema3F-Npn-2 signaling control distinct steps of motor axon growth and guidance during the formation of spinal motor connections. PMID:16364899

  16. 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

  17. 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

  18. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, D. T. (Inventor)

    1985-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  19. Regulator of G protein signaling 6 (RGS6) protein ensures coordination of motor movement by modulating GABAB receptor signaling.

    PubMed

    Maity, Biswanath; Stewart, Adele; Yang, Jianqi; Loo, Lipin; Sheff, David; Shepherd, Andrew J; Mohapatra, Durga P; Fisher, Rory A

    2012-02-10

    γ-Aminobutyric acid (GABA) release from inhibitory interneurons located within the cerebellar cortex limits the extent of neuronal excitation in part through activation of metabotropic GABA(B) receptors. Stimulation of these receptors triggers a number of downstream signaling events, including activation of GIRK channels by the Gβγ dimer resulting in membrane hyperpolarization and inhibition of neurotransmitter release from presynaptic sites. Here, we identify RGS6, a member of the R7 subfamily of RGS proteins, as a key regulator of GABA(B)R signaling in cerebellum. RGS6 is enriched in the granule cell layer of the cerebellum along with neuronal GIRK channel subunits 1 and 2 where RGS6 forms a complex with known binding partners Gβ(5) and R7BP. Mice lacking RGS6 exhibit abnormal gait and ataxia characterized by impaired rotarod performance improved by treatment with a GABA(B)R antagonist. RGS6(-/-) mice administered baclofen also showed exaggerated motor coordination deficits compared with their wild-type counterparts. Isolated cerebellar neurons natively expressed RGS6, GABA(B)R, and GIRK channel subunits, and cerebellar granule neurons from RGS6(-/-) mice showed a significant delay in the deactivation kinetics of baclofen-induced GIRK channel currents. These results establish RGS6 as a key component of GABA(B)R signaling and represent the first demonstration of an essential role for modulatory actions of RGS proteins in adult cerebellum. Dysregulation of RGS6 expression in human patients could potentially contribute to loss of motor coordination and, thus, pharmacological manipulation of RGS6 levels might represent a viable means to treat patients with ataxias of cerebellar origin. PMID:22179605

  20. Regulator of G Protein Signaling 6 (RGS6) Protein Ensures Coordination of Motor Movement by Modulating GABAB Receptor Signaling*

    PubMed Central

    Maity, Biswanath; Stewart, Adele; Yang, Jianqi; Loo, Lipin; Sheff, David; Shepherd, Andrew J.; Mohapatra, Durga P.; Fisher, Rory A.

    2012-01-01

    γ-Aminobutyric acid (GABA) release from inhibitory interneurons located within the cerebellar cortex limits the extent of neuronal excitation in part through activation of metabotropic GABAB receptors. Stimulation of these receptors triggers a number of downstream signaling events, including activation of GIRK channels by the Gβγ dimer resulting in membrane hyperpolarization and inhibition of neurotransmitter release from presynaptic sites. Here, we identify RGS6, a member of the R7 subfamily of RGS proteins, as a key regulator of GABABR signaling in cerebellum. RGS6 is enriched in the granule cell layer of the cerebellum along with neuronal GIRK channel subunits 1 and 2 where RGS6 forms a complex with known binding partners Gβ5 and R7BP. Mice lacking RGS6 exhibit abnormal gait and ataxia characterized by impaired rotarod performance improved by treatment with a GABABR antagonist. RGS6−/− mice administered baclofen also showed exaggerated motor coordination deficits compared with their wild-type counterparts. Isolated cerebellar neurons natively expressed RGS6, GABABR, and GIRK channel subunits, and cerebellar granule neurons from RGS6−/− mice showed a significant delay in the deactivation kinetics of baclofen-induced GIRK channel currents. These results establish RGS6 as a key component of GABABR signaling and represent the first demonstration of an essential role for modulatory actions of RGS proteins in adult cerebellum. Dysregulation of RGS6 expression in human patients could potentially contribute to loss of motor coordination and, thus, pharmacological manipulation of RGS6 levels might represent a viable means to treat patients with ataxias of cerebellar origin. PMID:22179605

  1. Electrical Motor Current Signal Analysis using a Dynamic Time Warping Method for Fault Diagnosis

    NASA Astrophysics Data System (ADS)

    Zhen, D.; Alibarbar, A.; Zhou, X.; Gu, F.; Ball, A. D.

    2011-07-01

    This paper presents the analysis of phase current signals to identify and quantify common faults from an electrical motor based on dynamic time warping (DTW) algorithm. In condition monitoring, measurements are often taken when the motor undertakes varying loads and speeds. The signals acquired in these conditions show similar profiles but have phase shifts, which do not line up in the time-axis for adequate comparison to discriminate the small changes in machine health conditions. In this study, DTW algorithms are exploited to align the signals to an ideal current signal constructed based on average operating conditions. In this way, comparisons between the signals can be made directly in the time domain to obtain residual signals. These residual signals are then based on to extract features for detecting and diagnosing the faults of the motor and components operating under different loads and speeds. This study provides a novel approach to the analysis of electrical current signal for diagnosis of motor faults. Experimental data sets of electrical motor current signals have been studied using DTW algorithms. Results show that DTW based residual signals highlights more the modulations due to the compressor process. And hence can obtain better fault detection and diagnosis results.

  2. Feeling the force: returning haptic signals influence effort inference during motor coordination.

    PubMed

    Ganesh, G; Osu, R; Naito, E

    2013-01-01

    Our brain is known to automatically optimize effort expenditure during motor coordination, such that for example, during bimanual braking of a bicycle, a well-oiled brake will automatically be used more than a corroded, heavy brake. But how does our brain infer the effort expenditure? All previous motor coordination models have believed that the effort in a task is known precisely to our brain, solely from the motor commands it generates. Here we show that this belief is incorrect. Through experiments and simulation we exhibit that in addition to the motor commands, the returning haptic signals play a crucial role in the inference of the effort during a force sharing task. Our results thus elucidate a previously unknown sensory-motor association that has major ramifications for our understanding of motor coordination and provides new insights into how sensory modifications due to ergonomics, stroke and disease can affect motor coordination in humans. PMID:24026052

  3. 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

  4. 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

  5. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

    1987-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  6. 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

  7. Signal transmission from motor axons to group Ia muscle spindle afferents: frequency responses and second-order non-linearities.

    PubMed

    Windhorst, U; Kokkoroyiannis, T; Laouris, Y; Meyer-Lohmann, J

    1994-03-01

    Spinal recurrent inhibition via Renshaw cells and proprioceptive feedback via skeletal muscle and muscle spindle afferents have been hypothesized to constitute a compound feedback system [Windhorst (1989) Afferent Control of Posture and Locomotion; Windhorst (1993) Robots and Biological Systems--Towards a New Bionics]. To assess their detailed functions, it is necessary to know their dynamic characteristics. Previously we have extensively described the properties of signal transmission from motor axons to Renshaw cells using random motor axon stimulation and data analysis methods based thereupon. Using the same methods, we here compare these properties, in the cat, with those between motor axons and group Ia muscle spindle afferents in terms of frequency responses and nonlinear features. The frequency responses depend on the mean rate (carrier rate) of activation of motor axons and on the strength of coupling between motor units and spindles. In general, they are those of a second-order low-pass system with a cut-off at fairly low frequencies. This contrasts with the dynamics of motor axon-Renshaw cell couplings which are those of a much broader band-pass with its peak in the range of c. 2-15 Hz [Christakos (1987) Neuroscience 23, 613-623]. The second-order non-linearities in motor unit-muscle spindle signal lines are much more diverse than those in motor axon-Renshaw cell couplings. Although the average strength of response declines with mean stimulus rate in both subsystems, there is no systematic relationship between the amount of non-linearity and the average response in the former, whilst there is in the latter. The qualitative appearance of motor unit-muscle spindle non-linearities was complicated as was the average response to motor unit twitches. Thus, whilst Renshaw cells appear to dynamically reflect motor output rather faithfully, muscle spindles seem to signal local muscle fibre length changes and their dynamics. This would be consistent with the

  8. Analysis of electrical and magnetic bio-signals associated with motor performance and fatigue

    NASA Astrophysics Data System (ADS)

    Yao, Bing

    This dissertation reports findings centered principally on comprehensive research related to human bio-signals (EEG, MEG, EMG and fMRI) acquired during repetitive maximal voluntary contractions (MVC) that induced severe fatigue. Fatigue is a common experience that reduces productivity and quality of life and increases chances of injury. Although abundant information has been gained in the last several decades regarding muscular and spinal-level mechanisms of muscle fatigue, very little is known about how cortical centers control and respond to fatigue. The main purpose of this study was to examine the fatigue effects on the central nervous system by analyzing the bio-signals collected in the designed experiments. Healthy human subjects were asked to perform a series of repetitive handgrip MVCs with their dominant hand until exhaustion. Handgrip forces, electrical activity (EMG) from primary and non-primary muscles, and EEG, MEG, or fMRI signals from different locations of the brain were recorded simultaneously. The time series data were segmented into several physiologically meaningful epochs (time phases), from rest to preparation to movement execution/sustaining. A series of studies, including motor-related cortical potential (MRCP) analysis, power spectrum analysis, time-frequency (spectrogram) analysis of EEG, EEG source localization and nonlinear analysis (fractal dimension and largest Lyapunov exponent), and fMRI analysis, was applied to the data. We hypothesized that the fatigue effects would act differently on brain signals of different phases. The MRCP results showed that the negative potential (NP) related to motor task preparation only had minimal changes with fatigue. The power of all EEG frequencies did not alter significantly during the preparation phase but decreased significantly during the sustained phase of the contraction. The fractal dimension and the largest Lyapunov exponent decreased significantly during the sustained phase as fatigue

  9. 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

  10. Piezoelectric motor development at AlliedSignal Inc., Kansas City Division

    SciTech Connect

    Pressly, R.B.; Mentesana, C.P.

    1994-11-01

    The Kansas City Division of AlliedSignal Inc. has been investigating the fabrication and use of piezoelectric motors in mechanisms for United States Department of Energy (DOE) weapons applications for about four years. These motors exhibit advantages over solenoids and other electromagnetic actuators. Prototype processes have been developed for complete fabrication of motors from stock materials, including abrasive machining of piezoelectric ceramics and more traditional machining of other motor components, electrode plating and sputtering, electric poling, cleaning, bonding and assembly. Drive circuits have been fabricated and motor controls are being developed. Laboratory facilities have been established for electrical/mechanical testing and evaluation of piezo materials and completed motors. Recent project efforts have focused on the potential of piezoelectric devices for commercial and industrial use. A broad range of various motor types and application areas has been identified, primarily in Japan. The Japanese have been developing piezo motors for many years and have more recently begun commercialization. Piezoelectric motor and actuator technology is emerging in the United States and quickly gaining in commercial interest. The Kansas City Division is continuing development of piezoelectric motors and actuators for defense applications while supporting and participating in the commercialization of piezoelectric devices with private industry through various technology transfer and cooperative development initiatives.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. Rhythmic Cortical Neurons Increase their Oscillations and Sculpt Basal Ganglia Signaling During Motor Learning

    PubMed Central

    Day, Nancy F.; Nick, Teresa A.

    2014-01-01

    The function and modulation of neural circuits underlying motor skill may involve rhythmic oscillations (Feller, 1999; Marder and Goaillard, 2006; Churchland et al., 2012). In the proposed pattern generator for birdsong, the cortical nucleus HVC, the frequency and power of oscillatory bursting during singing increases with development (Crandall et al., 2007; Day et al., 2009). We examined the maturation of cellular activity patterns that underlie these changes. Single unit ensemble recording combined with antidromic identification (Day et al., 2011) was used to study network development in anesthetized zebra finches. Autocovariance quantified oscillations within single units. A subset of neurons oscillated in the theta/alpha/mu/beta range (8–20 Hz), with greater power in adults compared to juveniles. Across the network, the normalized oscillatory power in the 8–20 Hz range was greater in adults than juveniles. In addition, the correlated activity between rhythmic neuron pairs increased with development. We next examined the functional impact of the oscillators on the output neurons of HVC. We found that the firing of oscillatory neurons negatively correlated with the activity of cortico-basal ganglia neurons (HVCXs), which project to Area X (the song basal ganglia). If groups of oscillators work together to tonically inhibit and precisely control the spike timing of adult HVCXs with coordinated release from inhibition, then the activity of HVCXs in juveniles should be decreased relative to adults due to uncorrelated, tonic inhibition. Consistent with this hypothesis, HVCXs had lower activity in juveniles. These data reveal network changes that shape cortical-to-basal ganglia signaling during motor learning. PMID:23776169

  1. 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.

  2. Motor-related signals in the auditory system for listening and learning.

    PubMed

    Schneider, David M; Mooney, Richard

    2015-08-01

    In the auditory system, corollary discharge signals are theorized to facilitate normal hearing and the learning of acoustic behaviors, including speech and music. Despite clear evidence of corollary discharge signals in the auditory cortex and their presumed importance for hearing and auditory-guided motor learning, the circuitry and function of corollary discharge signals in the auditory cortex are not well described. In this review, we focus on recent developments in the mouse and songbird that provide insights into the circuitry that transmits corollary discharge signals to the auditory system and the function of these signals in the context of hearing and vocal learning. PMID:25827273

  3. Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

    NASA Astrophysics Data System (ADS)

    Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

    2013-01-01

    Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time

  4. Phase-compensation-based dynamic time warping for fault diagnosis using the motor current signal

    NASA Astrophysics Data System (ADS)

    Zhen, D.; Zhao, H. L.; Gu, F.; Ball, A. D.

    2012-05-01

    Dynamic time warping (DTW) is a time-domain-based method and widely used in various similar recognition and data mining applications. This paper presents a phase-compensation-based DTW to process the motor current signals for detecting and quantifying various faults in a two-stage reciprocating compressor under different operating conditions. DTW is an effective method to align two signals for dissimilarity analysis. However, it has drawbacks such as singularities and high computational demands that limit its application in processing motor current signals for obtaining modulation characteristics accurately in diagnosing compressor faults. Therefore, a phase compensation approach is developed to reduce the singularity effect and a sliding window is designed to improve computing efficiency. Based on the proposed method, the motor current signals measured from the compressor induced with different common faults are analysed for fault diagnosis. Results show that residual signal analysis using the phase-compensation-based DTW allows the fault-related sideband features to be resolved more accurately for obtaining reliable fault detection and diagnosis. It provides an effective and easy approach to the analysis of motor current signals for better diagnosis in the time domain in comparison with conventional Fourier-transform-based methods.

  5. 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

  6. 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.

  7. Classification of Motor Imagery EEG Signals with Support Vector Machines and Particle Swarm Optimization.

    PubMed

    Ma, Yuliang; Ding, Xiaohui; She, Qingshan; Luo, Zhizeng; Potter, Thomas; Zhang, Yingchun

    2016-01-01

    Support vector machines are powerful tools used to solve the small sample and nonlinear classification problems, but their ultimate classification performance depends heavily upon the selection of appropriate kernel and penalty parameters. In this study, we propose using a particle swarm optimization algorithm to optimize the selection of both the kernel and penalty parameters in order to improve the classification performance of support vector machines. The performance of the optimized classifier was evaluated with motor imagery EEG signals in terms of both classification and prediction. Results show that the optimized classifier can significantly improve the classification accuracy of motor imagery EEG signals. PMID:27313656

  8. Bone morphogenetic protein signaling in vertebrate motor neurons and neuromuscular communication

    PubMed Central

    Osses, Nelson; Henríquez, Juan P.

    2015-01-01

    An accurate communication between motor neurons and skeletal muscle fibers is required for the proper assembly, growth and maintenance of neuromuscular junctions (NMJs). Several signaling and extracellular matrix molecules play stimulatory and inhibitory roles on the assembly of functional synapses. Studies in Drosophila have revealed crucial functions for early morphogens, such as members of the Wnt and Bone Morphogenetic Proteins (BMP) signaling pathways, during the assembly and maturation of the NMJ. Here, we bring together recent findings that led us to propose that BMPs also work in vertebrate organisms as diffusible cues to communicate motor neurons and skeletal muscles. PMID:25674047

  9. Classification of Motor Imagery EEG Signals with Support Vector Machines and Particle Swarm Optimization

    PubMed Central

    Ma, Yuliang; Ding, Xiaohui; She, Qingshan; Luo, Zhizeng; Potter, Thomas; Zhang, Yingchun

    2016-01-01

    Support vector machines are powerful tools used to solve the small sample and nonlinear classification problems, but their ultimate classification performance depends heavily upon the selection of appropriate kernel and penalty parameters. In this study, we propose using a particle swarm optimization algorithm to optimize the selection of both the kernel and penalty parameters in order to improve the classification performance of support vector machines. The performance of the optimized classifier was evaluated with motor imagery EEG signals in terms of both classification and prediction. Results show that the optimized classifier can significantly improve the classification accuracy of motor imagery EEG signals. PMID:27313656

  10. 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

  11. Near- Source, Seismo-Acoustic Signals Accompanying a NASCAR Race at the Texas Motor Speedway

    NASA Astrophysics Data System (ADS)

    Stump, B. W.; Hayward, C.; Underwood, R.; Howard, J. E.; MacPhail, M. D.; Golden, P.; Endress, A.

    2014-12-01

    Near-source, seismo-acoustic observations provide a unique opportunity to characterize urban sources, remotely sense human activities including vehicular traffic and monitor large engineering structures. Energy separately coupled into the solid earth and atmosphere provides constraints on not only the location of these sources but also the physics of the generating process. Conditions and distances at which these observations can be made are dependent upon not only local geological conditions but also atmospheric conditions at the time of the observations. In order to address this range of topics, an empirical, seismo-acoustic study was undertaken in and around the Texas Motor Speedway in the Dallas-Ft. Worth area during the first week of April 2014 at which time a range of activities associated with a series of NASCAR races occurred. Nine, seismic sensors were deployed around the 1.5-mile track for purposes of documenting the direct-coupled seismic energy from the passage of the cars and other vehicles on the track. Six infrasound sensors were deployed on a rooftop in a rectangular array configuration designed to provide high frequency beam forming for acoustic signals. Finally, a five-element infrasound array was deployed outside the track in order to characterize how the signals propagate away from the sources in the near-source region. Signals recovered from within the track were able to track and characterize the motion of a variety of vehicles during the race weekend including individual racecars. Seismic data sampled at 1000 sps documented strong Doppler effects as the cars approached and moved away from individual sensors. There were faint seismic signals that arrived at seismic velocity but local acoustic to seismic coupling as supported by the acoustic observations generated the majority of seismic signals. Actual seismic ground motions were small as demonstrated by the dominance of regional seismic signals from a magnitude 4.0 earthquake that arrived at

  12. 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

  13. 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

  14. 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

  15. Electrical Motor Current Signal Analysis using a Modulation Signal Bispectrum for the Fault Diagnosis of a Gearbox Downstream

    NASA Astrophysics Data System (ADS)

    Haram, M.; Wang, T.; Gu, F.; Ball, A. D.

    2012-05-01

    Motor current signal analysis has been an effective way for many years of monitoring electrical machines themselves. However, little work has been carried out in using this technique for monitoring their downstream equipment because of difficulties in extracting small fault components in the measured current signals. This paper investigates the characteristics of electrical current signals for monitoring the faults from a downstream gearbox using a modulation signal bispectrum (MSB), including phase effects in extracting small modulating components in a noisy measurement. An analytical study is firstly performed to understand amplitude, frequency and phase characteristics of current signals due to faults. It then explores the performance of MSB analysis in detecting weak modulating components in current signals. Experimental study based on a 10kw two stage gearbox, driven by a three phase induction motor, shows that MSB peaks at different rotational frequencies can be based to quantify the severity of gear tooth breakage and the degrees of shaft misalignment. In addition, the type and location of a fault can be recognized based on the frequency at which the change of MSB peak is the highest among different frequencies.

  16. 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

  17. Prediction of Hand Trajectory from Electrocorticography Signals in Primary Motor Cortex

    PubMed Central

    Nakanishi, Yasuhiko; Kambara, Hiroyuki; Yoshimura, Natsue; Nambu, Atsushi; Isa, Tadashi; Nishimura, Yukio; Koike, Yasuharu

    2013-01-01

    Due to their potential as a control modality in brain-machine interfaces, electrocorticography (ECoG) has received much focus in recent years. Studies using ECoG have come out with success in such endeavors as classification of arm movements and natural grasp types, regression of arm trajectories in two and three dimensions, estimation of muscle activity time series and so on. However, there still remains considerable work to be done before a high performance ECoG-based neural prosthetic can be realized. In this study, we proposed an algorithm to decode hand trajectory from 15 and 32 channel ECoG signals recorded from primary motor cortex (M1) in two primates. To determine the most effective areas for prediction, we applied two electrode selection methods, one based on position relative to the central sulcus (CS) and another based on the electrodes' individual prediction performance. The best coefficients of determination for decoding hand trajectory in the two monkeys were 0.4815±0.0167 and 0.7780±0.0164. Performance results from individual ECoG electrodes showed that those with higher performance were concentrated at the lateral areas and areas close to the CS. The results of prediction according with different numbers of electrodes based on proposed methods were also shown and discussed. These results also suggest that superior decoding performance can be achieved from a group of effective ECoG signals rather than an entire ECoG array. PMID:24386223

  18. AMPA Receptor-Induced Local Brain-Derived Neurotrophic Factor Signaling Mediates Motor Recovery after Stroke

    PubMed Central

    Clarkson, Andrew N.; Overman, Justine J.; Zhong, Sheng; Mueller, Rudolf; Lynch, Gary; Carmichael, S. Thomas

    2015-01-01

    Stroke is the leading cause of adult disability. Recovery after stroke shares similar molecular and cellular properties with learning and memory. A main component of learning-induced plasticity involves signaling through AMPA receptors (AMPARs). We systematically tested the role of AMPAR function in motor recovery in a mouse model of focal stroke. AMPAR function controls functional recovery beginning 5 d after the stroke. Positive allosteric modulators of AMPARs enhance recovery of limb control when administered after a delay from the stroke. Conversely, AMPAR antagonists impair motor recovery. The contributions of AMPARs to recovery are mediated by release of brain-derived neurotrophic factor (BDNF) in periinfarct cortex, as blocking local BDNF function in periinfarct cortex blocks AMPAR-mediated recovery and prevents the normal pattern of motor recovery. In contrast to a delayed AMPAR role in motor recovery, early administration of AMPAR agonists after stroke increases stroke damage. These findings indicate that the role of glutamate signaling through the AMPAR changes over time in stroke: early potentiation of AMPAR signaling worsens stroke damage, whereas later potentiation of the same signaling system improves functional recovery. PMID:21389231

  19. Signal peptides are allosteric activators of the protein translocase.

    PubMed

    Gouridis, Giorgos; Karamanou, Spyridoula; Gelis, Ioannis; Kalodimos, Charalampos G; Economou, Anastassios

    2009-11-19

    Extra-cytoplasmic polypeptides are usually synthesized as 'preproteins' carrying amino-terminal, cleavable signal peptides and secreted across membranes by translocases. The main bacterial translocase comprises the SecYEG protein-conducting channel and the peripheral ATPase motor SecA. Most proteins destined for the periplasm and beyond are exported post-translationally by SecA. Preprotein targeting to SecA is thought to involve signal peptides and chaperones like SecB. Here we show that signal peptides have a new role beyond targeting: they are essential allosteric activators of the translocase. On docking on their binding groove on SecA, signal peptides act in trans to drive three successive states: first, 'triggering' that drives the translocase to a lower activation energy state; second, 'trapping' that engages non-native preprotein mature domains docked with high affinity on the secretion apparatus; and third, 'secretion' during which trapped mature domains undergo several turnovers of translocation in segments. A significant contribution by mature domains renders signal peptides less critical in bacterial secretory protein targeting than currently assumed. Rather, it is their function as allosteric activators of the translocase that renders signal peptides essential for protein secretion. A role for signal peptides and targeting sequences as allosteric activators may be universal in protein translocases. PMID:19924216

  20. Electrical motor current signal analysis using a modified bispectrum for fault diagnosis of downstream mechanical equipment

    NASA Astrophysics Data System (ADS)

    Gu, F.; Shao, Y.; Hu, N.; Naid, A.; Ball, A. D.

    2011-01-01

    This paper presents the use of the induction motor current to identify and quantify common faults within a two-stage reciprocating compressor based on bispectrum analysis. The theoretical basis is developed to understand the nonlinear characteristics of current signals when the motor undertakes a varying load under different faulty conditions. Although conventional bispectrum representation of current signal allows the inclusion of phase information and the elimination of Gaussian noise, it produces unstable results due to random phase variation of the sideband components in the current signal. A modified bispectrum based on the amplitude modulation feature of the current signal is then adopted to combine both lower sidebands and higher sidebands simultaneously and hence characterise the current signal more accurately. Based on this new bispectrum analysis a more effective diagnostic feature, namely normalised bispectral peak, is developed for fault classification. In association with the kurtosis value of the raw current signal, the bispectrum feature gives rise to reliable fault classification results. In particular, the low feature values can differentiate the belt looseness from the other fault cases and different degrees of discharge valve leakage and inter-cooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to the analysis of stator current for the diagnosis of motor drive faults from downstream driving equipment.

  1. Synergistic integration of Netrin and ephrin axon guidance signals by spinal motor neurons

    PubMed Central

    Poliak, Sebastian; Morales, Daniel; Croteau, Louis-Philippe; Krawchuk, Dayana; Palmesino, Elena; Morton, Susan; Cloutier, Jean-François; Charron, Frederic; Dalva, Matthew B; Ackerman, Susan L; Kao, Tzu-Jen; Kania, Artur

    2015-01-01

    During neural circuit assembly, axonal growth cones are exposed to multiple guidance signals at trajectory choice points. While axonal responses to individual guidance cues have been extensively studied, less is known about responses to combination of signals and underlying molecular mechanisms. Here, we studied the convergence of signals directing trajectory selection of spinal motor axons entering the limb. We first demonstrate that Netrin-1 attracts and repels distinct motor axon populations, according to their expression of Netrin receptors. Quantitative in vitro assays demonstrate that motor axons synergistically integrate both attractive or repulsive Netrin-1 signals together with repulsive ephrin signals. Our investigations of the mechanism of ephrin-B2 and Netrin-1 integration demonstrate that the Netrin receptor Unc5c and the ephrin receptor EphB2 can form a complex in a ligand-dependent manner and that Netrin–ephrin synergistic growth cones responses involve the potentiation of Src family kinase signaling, a common effector of both pathways. DOI: http://dx.doi.org/10.7554/eLife.10841.001 PMID:26633881

  2. 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…

  3. 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

  4. Recognition Method of Limb Motor Imagery EEG Signals Based on Integrated Back-propagation Neural Network

    PubMed Central

    Li, Mingyang; Chen, Wanzhong; Cui, Bingyi; Tian, Yantao

    2015-01-01

    In this paper, in order to solve the existing problems of the low recognition rate and poor real-time performance in limb motor imagery, the integrated back-propagation neural network (IBPNN) was applied to the pattern recognition research of motor imagery EEG signals (imagining left-hand movement, imagining right-hand movement and imagining no movement). According to the motor imagery EEG data categories to be recognized, the IBPNN was designed to consist of 3 single three-layer back-propagation neural networks (BPNN), and every single neural network was dedicated to recognizing one kind of motor imagery. It simplified the complicated classification problems into three mutually independent two-class classifications by the IBPNN. The parallel computing characteristic of IBPNN not only improved the generation ability for network, but also shortened the operation time. The experimental results showed that, while comparing the single BPNN and Elman neural network, IBPNN was more competent in recognizing limb motor imagery EEG signals. Also among these three networks, IBPNN had the least number of iterations, the shortest operation time and the best consistency of actual output and expected output, and had lifted the success recognition rate above 97 percent while other single network is around 93 percent. PMID:25893019

  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. Predominance of Movement Speed Over Direction in Neuronal Population Signals of Motor Cortex: Intracranial EEG Data and A Simple Explanatory Model

    PubMed Central

    Hammer, Jiří; Pistohl, Tobias; Fischer, Jörg; Kršek, Pavel; Tomášek, Martin; Marusič, Petr; Schulze-Bonhage, Andreas; Aertsen, Ad; Ball, Tonio

    2016-01-01

    How neuronal activity of motor cortex is related to movement is a central topic in motor neuroscience. Motor-cortical single neurons are more closely related to hand movement velocity than speed, that is, the magnitude of the (directional) velocity vector. Recently, there is also increasing interest in the representation of movement parameters in neuronal population activity, such as reflected in the intracranial EEG (iEEG). We show that in iEEG, contrasting to what has been previously found on the single neuron level, speed predominates over velocity. The predominant speed representation was present in nearly all iEEG signal features, up to the 600–1000 Hz range. Using a model of motor-cortical signals arising from neuronal populations with realistic single neuron tuning properties, we show how this reversal can be understood as a consequence of increasing population size. Our findings demonstrate that the information profile in large population signals may systematically differ from the single neuron level, a principle that may be helpful in the interpretation of neuronal population signals in general, including, for example, EEG and functional magnetic resonance imaging. Taking advantage of the robust speed population signal may help in developing brain–machine interfaces exploiting population signals. PMID:26984895

  7. Predominance of Movement Speed Over Direction in Neuronal Population Signals of Motor Cortex: Intracranial EEG Data and A Simple Explanatory Model.

    PubMed

    Hammer, Jiří; Pistohl, Tobias; Fischer, Jörg; Kršek, Pavel; Tomášek, Martin; Marusič, Petr; Schulze-Bonhage, Andreas; Aertsen, Ad; Ball, Tonio

    2016-06-01

    How neuronal activity of motor cortex is related to movement is a central topic in motor neuroscience. Motor-cortical single neurons are more closely related to hand movement velocity than speed, that is, the magnitude of the (directional) velocity vector. Recently, there is also increasing interest in the representation of movement parameters in neuronal population activity, such as reflected in the intracranial EEG (iEEG). We show that in iEEG, contrasting to what has been previously found on the single neuron level, speed predominates over velocity. The predominant speed representation was present in nearly all iEEG signal features, up to the 600-1000 Hz range. Using a model of motor-cortical signals arising from neuronal populations with realistic single neuron tuning properties, we show how this reversal can be understood as a consequence of increasing population size. Our findings demonstrate that the information profile in large population signals may systematically differ from the single neuron level, a principle that may be helpful in the interpretation of neuronal population signals in general, including, for example, EEG and functional magnetic resonance imaging. Taking advantage of the robust speed population signal may help in developing brain-machine interfaces exploiting population signals. PMID:26984895

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. A new method of accurate broken rotor bar diagnosis based on modulation signal bispectrum analysis of motor current signals

    NASA Astrophysics Data System (ADS)

    Gu, F.; Wang, T.; Alwodai, A.; Tian, X.; Shao, Y.; Ball, A. D.

    2015-01-01

    Motor current signature analysis (MCSA) has been an effective way of monitoring electrical machines for many years. However, inadequate accuracy in diagnosing incipient broken rotor bars (BRB) has motivated many studies into improving this method. In this paper a modulation signal bispectrum (MSB) analysis is applied to motor currents from different broken bar cases and a new MSB based sideband estimator (MSB-SE) and sideband amplitude estimator are introduced for obtaining the amplitude at (1 ± 2 s)fs (s is the rotor slip and fs is the fundamental supply frequency) with high accuracy. As the MSB-SE has a good performance of noise suppression, the new estimator produces more accurate results in predicting the number of BRB, compared with conventional power spectrum analysis. Moreover, the paper has also developed an improved model for motor current signals under rotor fault conditions and an effective method to decouple the BRB current which interferes with that of speed oscillations associated with BRB. These provide theoretical supports for the new estimators and clarify the issues in using conventional bispectrum analysis.

  14. A plural role for lipids in motor neuron diseases: energy, signaling and structure

    PubMed Central

    Schmitt, Florent; Hussain, Ghulam; Dupuis, Luc; Loeffler, Jean-Philippe; Henriques, Alexandre

    2013-01-01

    Motor neuron diseases (MNDs) are characterized by selective death of motor neurons and include mainly adult-onset amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). Neurodegeneration is not the single pathogenic event occurring during disease progression. There are multiple lines of evidence for the existence of defects in lipid metabolism at peripheral level. For instance, hypermetabolism is well characterized in ALS, and dyslipidemia correlates with better prognosis in patients. Lipid metabolism plays also a role in other MNDs. In SMA, misuse of lipids as energetic nutrients is described in patients and in related animal models. The composition of structural lipids in the central nervous system is modified, with repercussion on membrane fluidity and on cell signaling mediated by bioactive lipids. Here, we review the main epidemiologic and mechanistic findings that link alterations of lipid metabolism and motor neuron degeneration, and we discuss the rationale of targeting these modifications for therapeutic management of MNDs. PMID:24600344

  15. 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

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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....

  1. 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....

  2. 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....

  3. 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....

  4. 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....

  5. Eph:ephrin-B1 forward signaling controls fasciculation of sensory and motor axons.

    PubMed

    Luxey, Maëva; Jungas, Thomas; Laussu, Julien; Audouard, Christophe; Garces, Alain; Davy, Alice

    2013-11-15

    Axon fasciculation is one of the processes controlling topographic innervation during embryonic development. While axon guidance steers extending axons in the accurate direction, axon fasciculation allows sets of co-extending axons to grow in tight bundles. The Eph:ephrin family has been involved both in axon guidance and fasciculation, yet it remains unclear how these two distinct types of responses are elicited. Herein we have characterized the role of ephrin-B1, a member of the ephrinB family in sensory and motor innervation of the limb. We show that ephrin-B1 is expressed in sensory axons and in the limb bud mesenchyme while EphB2 is expressed in motor and sensory axons. Loss of ephrin-B1 had no impact on the accurate dorso-ventral innervation of the limb by motor axons, yet EfnB1 mutants exhibited decreased fasciculation of peripheral motor and sensory nerves. Using tissue-specific excision of EfnB1 and in vitro experiments, we demonstrate that ephrin-B1 controls fasciculation of axons via a surround repulsion mechanism involving growth cone collapse of EphB2-expressing axons. Altogether, our results highlight the complex role of Eph:ephrin signaling in the development of the sensory-motor circuit innervating the limb. PMID:24056079

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. Signaling during platelet adhesion and activation

    PubMed Central

    Li, Zhenyu; Delaney, M. Keegan; O’Brien, Kelly A.; Du, Xiaoping

    2011-01-01

    Upon vascular injury, platelets are activated by adhesion to adhesive proteins like von Willebrand factor and collagen, or by soluble platelet agonists like ADP, thrombin, and thromboxane A2. These adhesive proteins and soluble agonists induce signal transduction via their respective receptors. The various receptor-specific platelet activation signaling pathways converge into common signaling events, which stimulate platelet shape change, granule secretion, and ultimately induce the “inside-out” signaling process leading to activation of the ligand binding function of integrin αIIbβ3. Ligand binding to integrin αIIbβ3 mediates platelet adhesion and aggregation and triggers “outside-in” signaling, resulting in platelet spreading, additional granule secretion, stabilization of platelet adhesion and aggregation, and clot retraction. It has become increasingly evident that agonist-induced platelet activation signals also crosstalk with integrin “outside-in” signals to regulate platelet responses. Platelet activation involves a series of rapid positive feedback loops that greatly amplify initial activation signals, and enable robust platelet recruitment and thrombus stabilization. Recent studies have provided novel insight into the molecular mechanisms of these processes. PMID:21071698

  12. 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

  13. 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

  14. Emotion affects action: Midcingulate cortex as a pivotal node of interaction between negative emotion and motor signals

    PubMed Central

    Pereira, M.G.; Oliveira, L; Erthal, FS; Joffily, M; Mocaiber, I.F.; Volchan, E.; Pessoa, L.

    2010-01-01

    Affective pictures drive the activity of brain networks and impact behavior. We showed previously that viewing unpleasant pictures interfered in the performance of a basic non-emotional visual detection task. In the present study, we employed functional magnetic resonance imaging to test the hypothesis that behavioral interference may result from the interaction between negatively valenced and motor-related signals in the brain. As in our previous study, subjects performed a simple target-detection task that followed the presentation of unpleasant or neutral pictures. Our results revealed that an unpleasant emotional context modulated evoked responses in several regions engaged by the simple target-detection task. In particular, the midcingulate cortex was recruited when participants performed target-detection trials during the unpleasant context and signal responses in this region closely mirrored the pattern of behavioral interference (as revealed via reaction time). Our findings suggest that the midcingulate cortex may be an important site for the interaction between negatively valenced and motor signals in the brain, and that it may be involved in the implementation of defensive responses, such as freezing. PMID:20233958

  15. 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

  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. 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.

  18. Quantification of the cortical contribution to the NIRS signal over the motor cortex using concurrent NIRS-fMRI measurements

    PubMed Central

    Gagnon, Louis; Yücel, Meryem A.; Dehaes, Mathieu; Cooper, Robert J.; Perdue, Katherine L.; Selb, Juliette; Huppert, Theodore J.; Hoge, Richard D.; Boas, David A.

    2011-01-01

    Near-Infrared Spectroscopy (NIRS) measures the functional hemodynamic response occuring at the surface of the cortex. Large pial veins are located above the surface of the cerebral cortex. Following activation, these veins exhibit oxygenation changes but their volume likely stays constant. The back-reflection geometry of the NIRS measurement renders the signal very sensitive to these superficial pial veins. As such, the measured NIRS signal contains contributions from both the cortical region as well as the pial vasculature. In this work, the cortical contribution to the NIRS signal was investigated using (1) Monte Carlo simulations over a realistic geometry constructed from anatomical and vascular MRI and (2) multimodal NIRS-BOLD recordings during motor stimulation. A good agreement was found between the simulations and the modeling analysis of in vivo measurements. Our results suggest that the cortical contribution to the deoxyhemoglobin signal change (ΔHbR) is equal to 16–22% of the cortical contribution to the total hemoglobin signal change (ΔHbT). Similarly, the cortical contribution of the oxyhemoglobin signal change (ΔHbO) is equal to 73–79% of the cortical contribution to the ΔHbT signal. These results suggest that ΔHbT is far less sensitive to pial vein contamination and therefore, it is likely that the ΔHbT signal provides better spatial specificity and should be used instead of ΔHbO or ΔHbR to map cerebral activity with NIRS. While different stimuli will result in different pial vein contributions, our finger tapping results do reveal the importance of considering the pial contribution. PMID:22036999

  19. 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

  20. A hybrid classifier fusion approach for motor unit potential classification during EMG signal decomposition.

    PubMed

    Rasheed, Sarbast; Stashuk, Daniel W; Kamel, Mohamed S

    2007-09-01

    In this paper, we propose a hybrid classifier fusion scheme for motor unit potential classification during electromyographic (EMG) signal decomposition. The scheme uses an aggregator module consisting of two stages of classifier fusion: the first at the abstract level using class labels and the second at the measurement level using confidence values. Performance of the developed system was evaluated using one set of real signals and two sets of simulated signals and was compared with the performance of the constituent base classifiers and the performance of a one-stage classifier fusion approach. Across the EMG signal data sets used and relative to the performance of base classifiers, the hybrid approach had better average classification performance overall. For the set of simulated signals of varying intensity, the hybrid classifier fusion system had on average an improved correct classification rate (CCr) (6.1%) and reduced error rate (Er) (0.4%). For the set of simulated signals of varying amounts of shape and/or firing pattern variability, the hybrid classifier fusion system had on average an improved CCr (6.2%) and reduced Er (0.9%). For real signals, the hybrid classifier fusion system had on average an improved CCr (7.5%) and reduced Er (1.7%). PMID:17867366

  1. 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

  2. Coupling mechanical forces to electrical signaling: molecular motors and the intracellular transport of ion channels.

    PubMed

    Barry, Joshua; Gu, Chen

    2013-04-01

    Proper localization of various ion channels is fundamental to neuronal functions, including postsynaptic potential plasticity, dendritic integration, action potential initiation and propagation, and neurotransmitter release. Microtubule-based forward transport mediated by kinesin motors plays a key role in placing ion channel proteins to correct subcellular compartments. PDZ- and coiled-coil-domain proteins function as adaptor proteins linking ionotropic glutamate and GABA receptors to various kinesin motors, respectively. Recent studies show that several voltage-gated ion channel/transporter proteins directly bind to kinesins during forward transport. Three major regulatory mechanisms underlying intracellular transport of ion channels are also revealed. These studies contribute to understanding how mechanical forces are coupled to electrical signaling and illuminating pathogenic mechanisms in neurodegenerative diseases. PMID:22910031

  3. Coupling Mechanical Forces to Electrical Signaling: Molecular Motors and the Intracellular Transport of Ion Channels

    PubMed Central

    Barry, Joshua; Gu, Chen

    2013-01-01

    Proper localization of various ion channels is fundamental to neuronal functions, including postsynaptic potential plasticity, dendritic integration, action potential initiation and propagation, and neurotransmitter release. Microtubule-based forward transport mediated by kinesin motors plays a key role in placing ion channel proteins to correct subcellular compartments. PDZ- and coiled-coil-domain proteins function as adaptor proteins linking ionotropic glutamate and GABA receptors to various kinesin motors, respectively. Recent studies show that several voltage-gated ion channel/transporter proteins directly bind to kinesins during forward transport. Three major regulatory mechanisms underlying intracellular transport of ion channels are also revealed. These studies contribute to understanding how mechanical forces are coupled to electrical signaling and illuminating pathogenic mechanisms in neurodegenerative diseases. PMID:22910031

  4. 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

  5. Impact of neural noise on a sensory-motor pathway signaling impending collision

    PubMed Central

    Jones, Peter W.

    2012-01-01

    Noise is a major concern in circuits processing electrical signals, including neural circuits. There are many factors that influence how noise propagates through neural circuits, and there are few systems in which noise levels have been studied throughout a processing pathway. We recorded intracellularly from multiple stages of a sensory-motor pathway in the locust that detects approaching objects. We found that responses are more variable and that signal-to-noise ratios (SNRs) are lower further from the sensory periphery. SNRs remain low even with the use of stimuli for which the pathway is most selective and for which the neuron representing its final sensory level must integrate many synaptic inputs. Modeling of this neuron shows that variability in the strength of individual synaptic inputs within a large population has little effect on the variability of the spiking output. In contrast, jitter in the timing of individual inputs and spontaneous variability is important for shaping the responses to preferred stimuli. These results suggest that neural noise is inherent to the processing of visual stimuli signaling impending collision and contributes to shaping neural responses along this sensory-motor pathway. PMID:22114160

  6. Motor unit action potential conduction velocity estimated from surface electromyographic signals using image processing techniques.

    PubMed

    Soares, Fabiano Araujo; Carvalho, João Luiz Azevedo; Miosso, Cristiano Jacques; de Andrade, Marcelino Monteiro; da Rocha, Adson Ferreira

    2015-01-01

    In surface electromyography (surface EMG, or S-EMG), conduction velocity (CV) refers to the velocity at which the motor unit action potentials (MUAPs) propagate along the muscle fibers, during contractions. The CV is related to the type and diameter of the muscle fibers, ion concentration, pH, and firing rate of the motor units (MUs). The CV can be used in the evaluation of contractile properties of MUs, and of muscle fatigue. The most popular methods for CV estimation are those based on maximum likelihood estimation (MLE). This work proposes an algorithm for estimating CV from S-EMG signals, using digital image processing techniques. The proposed approach is demonstrated and evaluated, using both simulated and experimentally-acquired multichannel S-EMG signals. We show that the proposed algorithm is as precise and accurate as the MLE method in typical conditions of noise and CV. The proposed method is not susceptible to errors associated with MUAP propagation direction or inadequate initialization parameters, which are common with the MLE algorithm. Image processing -based approaches may be useful in S-EMG analysis to extract different physiological parameters from multichannel S-EMG signals. Other new methods based on image processing could also be developed to help solving other tasks in EMG analysis, such as estimation of the CV for individual MUs, localization and tracking of innervation zones, and study of MU recruitment strategies. PMID:26384112

  7. 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.

  8. 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

  9. Dominance of local sensory signals over inter-segmental effects in a motor system: modeling studies.

    PubMed

    Daun-Gruhn, Silvia; Tóth, Tibor I; Borgmann, Anke

    2011-12-01

    Recent experiments, reported in the accompanying paper, have supplied key data on the impact afferent excitation has on the activity of the levator–depressor motor system of an extremity in the stick insect. The main finding was that, stimulation of the campaniform sensillae of the partially amputated middle leg in an animal where all other but one front leg had been removed, had a dominating effect over that of the stepping ipsilateral front leg. In fact,the latter effect was minute compared to the former. In this article, we propose a local network that involves the neuronal part of the levator–depressor motor system and use it to elucidate the mechanisms that underlie the generation of neuronal activity in the experiments. In particular, we show that by appropriately modulating the activity in the neurons of the central pattern generator of the levator–depressor motor system, we obtain activity patterns of the motoneurons in the model that closely resemble those found in extracellular recordings in the stick insect. In addition, our model predicts specific properties of these records which depend on the stimuli applied to the stick insect leg. We also discuss our results on the segmental mechanisms in the context of inter-segmental coordination. PMID:22290139

  10. Local synaptic signaling enhances the stochastic transport of motor-driven cargo in neurons

    NASA Astrophysics Data System (ADS)

    Newby, Jay; Bressloff, Paul C.

    2010-09-01

    The tug-of-war model of motor-driven cargo transport is formulated as an intermittent trapping process. An immobile trap, representing the cellular machinery that sequesters a motor-driven cargo for eventual use, is located somewhere within a microtubule track. A particle representing a motor-driven cargo that moves randomly with a forward bias is introduced at the beginning of the track. The particle switches randomly between a fast moving phase and a slow moving phase. When in the slow moving phase, the particle can be captured by the trap. To account for the possibility that the particle avoids the trap, an absorbing boundary is placed at the end of the track. Two local signaling mechanisms—intended to improve the chances of capturing the target—are considered by allowing the trap to affect the tug-of-war parameters within a small region around itself. The first is based on a localized adenosine triphosphate (ATP) concentration gradient surrounding a synapse, and the second is based on a concentration of tau—a microtubule-associated protein involved in Alzheimer's disease—coating the microtubule near the synapse. It is shown that both mechanisms can lead to dramatic improvements in the capture probability, with a minimal increase in the mean capture time. The analysis also shows that tau can cause a cargo to undergo random oscillations, which could explain some experimental observations.

  11. Local synaptic signaling enhances the stochastic transport of motor-driven cargo in neurons.

    PubMed

    Newby, Jay; Bressloff, Paul C

    2010-01-01

    The tug-of-war model of motor-driven cargo transport is formulated as an intermittent trapping process. An immobile trap, representing the cellular machinery that sequesters a motor-driven cargo for eventual use, is located somewhere within a microtubule track. A particle representing a motor-driven cargo that moves randomly with a forward bias is introduced at the beginning of the track. The particle switches randomly between a fast moving phase and a slow moving phase. When in the slow moving phase, the particle can be captured by the trap. To account for the possibility that the particle avoids the trap, an absorbing boundary is placed at the end of the track. Two local signaling mechanisms--intended to improve the chances of capturing the target--are considered by allowing the trap to affect the tug-of-war parameters within a small region around itself. The first is based on a localized adenosine triphosphate (ATP) concentration gradient surrounding a synapse, and the second is based on a concentration of tau--a microtubule-associated protein involved in Alzheimer's disease--coating the microtubule near the synapse. It is shown that both mechanisms can lead to dramatic improvements in the capture probability, with a minimal increase in the mean capture time. The analysis also shows that tau can cause a cargo to undergo random oscillations, which could explain some experimental observations. PMID:20733246

  12. 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.

  13. 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

  14. Motor Skill Learning Is Associated with Phase-Dependent Modifications in the Striatal cAMP/PKA/DARPP-32 Signaling Pathway in Rodents

    PubMed Central

    Qian, Yu; Forssberg, Hans; Diaz Heijtz, Rochellys

    2015-01-01

    Abundant evidence points to a key role of dopamine in motor skill learning, although the underlying cellular and molecular mechanisms are still poorly understood. Here, we used a skilled-reaching paradigm to first examine changes in the expression of the plasticity-related gene Arc to map activity in cortico-striatal circuitry during different phases of motor skill learning in young animals. In the early phase, Arc mRNA was significantly induced in the medial prefrontal cortex (mPFC), cingulate cortex, primary motor cortex, and striatum. In the late phase, expression of Arc did not change in most regions, except in the mPFC and dorsal striatum. In the second series of experiments, we studied the learning-induced changes in the phosphorylation state of dopamine and cAMP-regulated phosphoprotein, 32k Da (DARPP-32). Western blot analysis of the phosphorylation state of DARPP-32 and its downstream target cAMP response element-binding protein (CREB) in the striatum revealed that the early, but not late, phase of motor skill learning was associated with increased levels of phospho-Thr34-DARPP-32 and phospho-Ser133-CREB. Finally, we used the DARPP-32 knock-in mice with a point mutation in the Thr34 regulatory site (i.e., protein kinase A site) to test the significance of this pathway in motor skill learning. In accordance with our hypothesis, inhibition of DARPP-32 activity at the Thr34 regulatory site strongly attenuated the motor learning rate and skilled reaching performance of mice. These findings suggest that the cAMP/PKA/DARPP-32 signaling pathway is critically involved in the acquisition of novel motor skills, and also demonstrate a dynamic shift in the contribution of cortico-striatal circuitry during different phases of motor skill learning. PMID:26488498

  15. fMRI brain mapping during motion capture and FES induced motor tasks: signal to noise ratio assessment.

    PubMed

    Gandolla, Marta; Ferrante, Simona; Casellato, Claudia; Ferrigno, Giancarlo; Molteni, Franco; Martegani, Alberto; Frattini, Tiziano; Pedrocchi, Alessandra

    2011-10-01

    Functional Electrical Stimulation (FES) is a well known clinical rehabilitation procedure, however the neural mechanisms that underlie this treatment at Central Nervous System (CNS) level are still not completely understood. Functional magnetic resonance imaging (fMRI) is a suitable tool to investigate effects of rehabilitative treatments on brain plasticity. Moreover, monitoring the effective executed movement is needed to correctly interpret activation maps, most of all in neurological patients where required motor tasks could be only partially accomplished. The proposed experimental set-up includes a 1.5 T fMRI scanner, a motion capture system to acquire kinematic data, and an electro-stimulation device. The introduction of metallic devices and of stimulation current in the MRI room could affect fMRI acquisitions so as to prevent a reliable activation maps analysis. What we are interested in is that the Blood Oxygenation Level Dependent (BOLD) signal, marker of neural activity, could be detected within a given experimental condition and set-up. In this paper we assess temporal Signal to Noise Ratio (SNR) as image quality index. BOLD signal change is about 1-2% as revealed by a 1.5 T scanner. This work demonstrates that, with this innovative set-up, in the main cortical sensorimotor regions 1% BOLD signal change can be detected at least in the 93% of the sub-volumes, and almost 100% of the sub-volumes are suitable for 2% signal change detection. The integrated experimental set-up will therefore allows to detect FES induced movements fMRI maps simultaneously with kinematic acquisitions so as to investigate FES-based rehabilitation treatments contribution at CNS level. PMID:21550290

  16. 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

  17. Time course and spatial distribution of fMRI signal changes during single-pulse transcranial magnetic stimulation to the primary motor cortex.

    PubMed

    Shitara, H; Shinozaki, T; Takagishi, K; Honda, M; Hanakawa, T

    2011-06-01

    Simultaneous transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) may advance the understanding of neurophysiological mechanisms of TMS. However, it remains unclear if TMS induces fMRI signal changes consistent with the standard hemodynamic response function (HRF) in both local and remote regions. To address this issue, we delivered single-pulse TMS to the left M1 during simultaneous recoding of electromyography and time-resolved fMRI in 36 healthy participants. First, we examined the time-course of fMRI signals during supra- and subthreshold single-pulse TMS in comparison with those during voluntary right hand movement and electrical stimulation to the right median nerve (MNS). All conditions yielded comparable time-courses of fMRI signals, showing that HRF would generally provide reasonable estimates for TMS-evoked activity in the motor areas. However, a clear undershoot following the signal peak was observed only during subthreshold TMS in the left M1, suggesting a small but meaningful difference between the locally and remotely TMS-evoked activities. Second, we compared the spatial distribution of activity across the conditions. Suprathreshold TMS-evoked activity overlapped not only with voluntary movement-related activity but also partially with MNS-induced activity, yielding overlapped areas of activity around the stimulated M1. The present study has provided the first experimental evidence that motor area activity during suprathreshold TMS likely includes activity for processing of muscle afferents. A method should be developed to control the effects of muscle afferents for fair interpretation of TMS-induced motor area activity during suprathreshold TMS to M1. PMID:21396457

  18. 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

  19. 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.

  20. 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.

  1. Deficient Wnt signalling triggers striatal synaptic degeneration and impaired motor behaviour in adult mice

    PubMed Central

    Galli, Soledad; Lopes, Douglas M.; Ammari, Rachida; Kopra, Jaakko; Millar, Sarah E.; Gibb, Alasdair; Salinas, Patricia C.

    2014-01-01

    Synapse degeneration is an early and invariant feature of neurodegenerative diseases. Indeed, synapse loss occurs prior to neuronal degeneration and correlates with the symptom severity of these diseases. However, the molecular mechanisms that trigger synaptic loss remain poorly understood. Here we demonstrate that deficient Wnt signalling elicits synaptic degeneration in the adult striatum. Inducible expression of the secreted Wnt antagonist Dickkopf1 (Dkk1) in adult mice (iDkk1) decreases the number of cortico-striatal glutamatergic synapses and of D1 and D2 dopamine receptor clusters. Synapse loss occurs in the absence of axon retraction or cell death. The remaining excitatory terminals contain fewer synaptic vesicles and have a reduced probability of evoked transmitter release. IDkk1 mice show impaired motor coordination and are irresponsive to amphetamine. These studies identify Wnts as key endogenous regulators of synaptic maintenance and suggest that dysfunction in Wnt signalling contributes to synaptic degeneration at early stages in neurodegenerative diseases. PMID:25318560

  2. Real time moving object detection using motor signal and depth map for robot car

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Siu, Wan-Chi

    2013-12-01

    Moving object detection from a moving camera is a fundamental task in many applications. For the moving robot car vision, the background movement is 3D motion structure in nature. In this situation, the conventional moving object detection algorithm cannot be use to handle the 3D background modeling effectively and efficiently. In this paper, a novel scheme is proposed by utilizing the motor control signal and depth map obtained from a stereo camera to model the perspective transform matrix between different frames under a moving camera. In our approach, the coordinate relationship between frames during camera moving is modeled by a perspective transform matrix which is obtained by using current motor control signals and the pixel depth value. Hence, the relationship between a static background pixel and the moving foreground corresponding to the camera motion can be related by a perspective matrix. To enhance the robustness of classification, we allowed a tolerance range during the perspective transform matrix prediction and used multi-reference frames to classify the pixel on current frame. The proposed scheme has been found to be able to detect moving objects for our moving robot car efficiently. Different from conventional approaches, our method can model the moving background in 3D structure, without online model training. More importantly, the computational complexity and memory requirement are low making it possible to implement this scheme in real-time, which is even valuable for a robot vision system.

  3. 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

  4. 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

  5. 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

  6. 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

  7. Pitx3 deficiency produces decreased dopamine signaling and induces motor deficits in Pitx3(-/-) mice.

    PubMed

    Le, Weidong; Zhang, Lifen; Xie, Wenjie; Li, Song; Dani, John A

    2015-12-01

    Midbrain dopamine (DA) neurons are involved in cognition, control of motor activity, and emotion-related behaviors. Degeneration of DA neurons particularly in the substantia nigra is a hallmark of Parkinson's disease. The homeobox transcription factor, Pitx3, plays a critical role in the development, function, and maintenance of midbrain DA neurons. We found that in young adult Pitx3-null mice, Pitx3(-/-), there was decreased tyrosine hydroxylase staining, indicating a loss of DA neurons particularly in the substantia nigra. In addition, fast-scan cyclic voltammetry and microdialysis assays of DA release indicated that the lack of Pitx3 caused a significant reduction of striatal DA release. Tonic DA release was impaired more significantly than the phasic DA release induced by burst firing of DA neurons. Furthermore, behavioral tests revealed that Pitx3(-/-) mice displayed abnormal motor activities, including impaired motor coordination and decreased locomotion. In summary, these data provide further evidence that Pitx3 is specifically required for DA-related function and, if impaired, Pitx3 could contribute during the pathogenesis of Parkinson's disease. PMID:26363812

  8. 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

  9. 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

  10. 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

  11. Paired inhibitory and activating receptor signals.

    PubMed

    Taylor, L S; Paul, S P; McVicar, D W

    2000-01-01

    The immunological literature has become inundated with reports regarding paired inhibitory receptors. Paired inhibitory receptor systems are highly conserved families that contain receptors involved in either cellular inhibition or activation. In most cases the paired putative biochemical antagonists are co-expressed on a given cell and thought to bind similar, if not identical, ligands making their biological role difficult to understand. Examples of these systems include immunoglobulin (Ig)-like receptors (Killer Ig Receptors, Immunoglobulin-like Transcripts/Leukocyte Ig-like Receptors/Monocyte Macrophage Ig Receptors, and Paired Ig-like Receptors), and type II lectin-like receptor systems (NKG2 and Ly49). General characteristics of these inhibitory receptors include a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM). The ITIM is phosphorylated upon engagement and recruits protein tyrosine phosphatases that dephosphorylate cellular substrates that would otherwise mediate activation. In contrast, the activating receptors of these pairs use charged residues within their transmembrane domains to associate with various signal transduction chains including the gamma chain of the receptor for the Fc portion of IgE, DAP12 or DAP10. Once phosphorylated, these chains direct the signal transduction cascade resulting in cellular activation. Here we review the signaling of several paired systems and present the current models for their signal transduction cascades. PMID:11258418

  12. 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

  13. 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

  14. Principal components of hand kinematics and neurophysiological signals in motor cortex during reach to grasp movements

    PubMed Central

    Aggarwal, Vikram; Thakor, Nitish V.; Schieber, Marc H.

    2014-01-01

    A few kinematic synergies identified by principal component analysis (PCA) account for most of the variance in the coordinated joint rotations of the fingers and wrist used for a wide variety of hand movements. To examine the possibility that motor cortex might control the hand through such synergies, we collected simultaneous kinematic and neurophysiological data from monkeys performing a reach-to-grasp task. We used PCA, jPCA and isomap to extract kinematic synergies from 18 joint angles in the fingers and wrist and analyzed the relationships of both single-unit and multiunit spike recordings, as well as local field potentials (LFPs), to these synergies. For most spike recordings, the maximal absolute cross-correlations of firing rates were somewhat stronger with an individual joint angle than with any principal component (PC), any jPC or any isomap dimension. In decoding analyses, where spikes and LFP power in the 100- to 170-Hz band each provided better decoding than other LFP-based signals, the first PC was decoded as well as the best decoded joint angle. But the remaining PCs and jPCs were predicted with lower accuracy than individual joint angles. Although PCs, jPCs or isomap dimensions might provide a more parsimonious description of kinematics, our findings indicate that the kinematic synergies identified with these techniques are not represented in motor cortex more strongly than the original joint angles. We suggest that the motor cortex might act to sculpt the synergies generated by subcortical centers, superimposing an ability to individuate finger movements and adapt the hand to grasp a wide variety of objects. PMID:24990564

  15. Microbiota-gut-brain signalling in Parkinson's disease: Implications for non-motor symptoms.

    PubMed

    Felice, Valeria D; Quigley, Eamonn M; Sullivan, Aideen M; O'Keeffe, Gerard W; O'Mahony, Siobhain M

    2016-06-01

    Parkinson's disease is the second most common neurodegenerative disorder, affecting 1-2% of the population over 65 years of age. The primary neuropathology is the loss of midbrain dopaminergic neurons, resulting in characteristic motor deficits, upon which the clinical diagnosis is based. However, a number of significant non-motor symptoms (NMS) are also evident that appear to have a greater impact on the quality of life of these patients. In recent years, it has become increasingly apparent that neurobiological processes can be modified by the bi-directional communication that occurs along the brain-gut axis. The microbiota plays a key role in this communication throughout different routes in both physiological and pathological conditions. Thus, there has been an increasing interest in investigating how microbiota changes within the gastrointestinal tract may be implicated in health and disease including PD. Interestingly α-synuclein-aggregates, the cardinal neuropathological feature in PD, are present in both the submucosal and myenteric plexuses of the enteric nervous system, prior to their appearance in the brain, indicating a possible gut to brain route of "prion-like" spread. In this review we highlight the potential importance of gut to brain signalling in PD with particular focus on the role of the microbiota as major player in this communication. PMID:27013171

  16. 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

  17. Distinct target-derived signals organize formation, maturation, and maintenance of motor nerve terminals.

    PubMed

    Fox, Michael A; Sanes, Joshua R; Borza, Dorin-Bogdan; Eswarakumar, Veraragavan P; Fässler, Reinhard; Hudson, Billy G; John, Simon W M; Ninomiya, Yoshifumi; Pedchenko, Vadim; Pfaff, Samuel L; Rheault, Michelle N; Sado, Yoshikazu; Segal, Yoav; Werle, Michael J; Umemori, Hisashi

    2007-04-01

    Target-derived factors organize synaptogenesis by promoting differentiation of nerve terminals at synaptic sites. Several candidate organizing molecules have been identified based on their bioactivities in vitro, but little is known about their roles in vivo. Here, we show that three sets of organizers act sequentially to pattern motor nerve terminals: FGFs, beta2 laminins, and collagen alpha(IV) chains. FGFs of the 7/10/22 subfamily and broadly distributed collagen IV chains (alpha1/2) promote clustering of synaptic vesicles as nerve terminals form. beta2 laminins concentrated at synaptic sites are dispensable for embryonic development of nerve terminals but are required for their postnatal maturation. Synapse-specific collagen IV chains (alpha3-6) accumulate only after synapses are mature and are required for synaptic maintenance. Thus, multiple target-derived signals permit discrete control of the formation, maturation, and maintenance of presynaptic specializations. PMID:17418794

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. Analysis of neural activity in human motor cortex -- Towards brain machine interface system

    NASA Astrophysics Data System (ADS)

    Secundo, Lavi

    The discovery of directional tuned neurons in the primary motor cortex has advanced motor research in several domains. For instance, in the area of brain machine interface (BMI), researchers have exploited the robust characteristic of tuned motor neurons to allow monkeys to learn control of various machines. In the first chapter of this work we examine whether this phenomena can be observed using the less invasive method of recording electrocorticographic signals (ECoG) from the surface of a human's brain. Our findings reveal that individual ECoG channels contain complex movement information about the neuronal population. While some ECoG channels are tuned to hand movement direction (direction specific channels), others are associated to movement but do not contain information regarding movement direction (non-direction specific channels). More specifically, directionality can vary temporally and by frequency within one channel. In addition, a handful of channels contain no significant information regarding movement at all. These findings strongly suggest that directional and non-directional regions of cortex can be identified with ECoG and provide solutions to decoding movement at the signal resolution provided by ECoG. In the second chapter we examine the influence of movement context on movement reconstruction accuracy. We recorded neuronal signals recorded from electro-corticography (ECoG) during performance of cued- and self-initiated movements. ECoG signals were used to train a reconstruction algorithm to reconstruct continuous hand movement. We found that both cued- and self-initiated movements could be reconstructed with similar accuracy from the ECoG data. However, while an algorithm trained on the cued task could reconstruct performance on a subsequent cued trial, it failed to reconstruct self-initiated arm movement. The same task-specificity was observed when the algorithm was trained with self-initiated movement data and tested on the cued task. Thus

  8. 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

  9. D1 dopamine receptor signaling is modulated by the R7 RGS protein EAT-16 and the R7 binding protein RSBP-1 in Caenoerhabditis elegans motor neurons.

    PubMed

    Wani, Khursheed A; Catanese, Mary; Normantowicz, Robyn; Herd, Muriel; Maher, Kathryn N; Chase, Daniel L

    2012-01-01

    Dopamine signaling modulates voluntary movement and reward-driven behaviors by acting through G protein-coupled receptors in striatal neurons, and defects in dopamine signaling underlie Parkinson's disease and drug addiction. Despite the importance of understanding how dopamine modifies the activity of striatal neurons to control basal ganglia output, the molecular mechanisms that control dopamine signaling remain largely unclear. Dopamine signaling also controls locomotion behavior in Caenorhabditis elegans. To better understand how dopamine acts in the brain we performed a large-scale dsRNA interference screen in C. elegans for genes required for endogenous dopamine signaling and identified six genes (eat-16, rsbp-1, unc-43, flp-1, grk-1, and cat-1) required for dopamine-mediated behavior. We then used a combination of mutant analysis and cell-specific transgenic rescue experiments to investigate the functional interaction between the proteins encoded by two of these genes, eat-16 and rsbp-1, within single cell types and to examine their role in the modulation of dopamine receptor signaling. We found that EAT-16 and RSBP-1 act together to modulate dopamine signaling and that while they are coexpressed with both D1-like and D2-like dopamine receptors, they do not modulate D2 receptor signaling. Instead, EAT-16 and RSBP-1 act together to selectively inhibit D1 dopamine receptor signaling in cholinergic motor neurons to modulate locomotion behavior. PMID:22629462

  10. 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

  11. Notum deacylates Wnts to suppress signalling activity

    PubMed Central

    Howell, Steve; Chang, Tao-Hsin; Liu, Yan; Feizi, Ten; Bineva, Ganka; O’Reilly, Nicola; Snijders, Ambrosius P.; Jones, E. Yvonne; Vincent, Jean-Paul

    2015-01-01

    Signalling by Wnts is finely balanced to ensure normal development and tissue homeostasis while avoiding diseases such as cancer. This is achieved in part by Notum, a highly conserved secreted feedback antagonist. Notum has been thought to act as a phospholipase, shedding glypicans and associated Wnts from the cell surface. However, this view fails to explain specificity since glypicans bind many extracellular ligands. Here we provide genetic evidence in Drosophila that Notum requires glypicans to suppress Wnt signalling, but does not cleave their glycophosphatidylinositol anchor. Structural analyses reveal glycosaminoglycan binding sites on Notum, which likely help Notum colocalise with Wnts. They also identify, at the active site of human and Drosophila Notum, a large hydrophobic pocket that accommodates palmitoleate. Kinetic and mass spectrometric analyses of human proteins show that Notum is a carboxylesterase that removes an essential palmitoleate moiety from Wnts and thus constitutes the first known extracellular protein deacylase. PMID:25731175

  12. [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

  13. 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

  14. 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

  15. 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

  16. Endogenous cannabinoid signaling through the CB1 receptor is essential for cerebellum-dependent discrete motor learning.

    PubMed

    Kishimoto, Yasushi; Kano, Masanobu

    2006-08-23

    Cannabinoids exert their psychomotor actions through the CB1 cannabinoid receptor in the brain. Genetic deletion of CB1 in mice causes various symptoms, including changes in locomotor activity, increased ring catalepsy, supraspinal hypoalgesia, and impaired memory extinction. Although the cerebellar cortex contains the highest level of CB1, severe cerebellum-related functional deficits have not been reported in CB1 knock-out mice. To clarify the roles of CB1 in cerebellar function, we subjected CB1 knock-out mice to a delay version of classical eyeblink conditioning. This paradigm is a test for cerebellum-dependent discrete motor learning, in which conditioned stimulus (CS) (352 ms tone) and unconditioned stimulus (US) (100 ms periorbital electrical shock) are coterminated. We found that delay eyeblink conditioning performance was severely impaired in CB1 knock-out mice. In contrast, they exhibited normal performance in a trace version of eyeblink conditioning with 500 ms stimulus-free interval intervened between the CS offset and the US onset. This paradigm is a test for hippocampus-dependent associative learning. Sensitivity of CB1 knock-out mice to CS or US was normal, suggesting that impaired delay eyeblink conditioning is attributable to defects in association of responses to CS and US. We also found that intraperitoneal injection of the CB1 antagonist SR141716A [N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole carboxamide] to wild-type mice caused severe impairment in acquisition but not extinction of delay eyeblink conditioning. SR141716A treatment had no effect on trace eyeblink conditioning with a 500 or 750 ms trace interval. These results indicate that endogenous cannabinoid signaling through CB1 is essential for cerebellum-dependent discrete motor learning, especially for its acquisition. PMID:16928872

  17. Modulation of Premotor and Primary Motor Cortical Activity during Volitional Adjustments of Speed-Accuracy Trade-Offs.

    PubMed

    Thura, David; Cisek, Paul

    2016-01-20

    Recent work suggests that while animals decide between reaching actions, neurons in dorsal premotor (PMd) and primary motor (M1) cortex reflect a dynamic competition between motor plans and determine when commitment to a choice is made. This competition is biased by at least two sources of information: the changing sensory evidence for one choice versus another, and an urgency signal that grows over time. Here, we test the hypothesis that the urgency signal adjusts the trade-off between speed and accuracy during both decision-making and movement execution. Two monkeys performed a reaching decision task in which sensory evidence continuously evolves over the course of each trial. In different blocks, task timing parameters encouraged monkeys to voluntarily adapt their behavior to be either hasty or conservative. Consistent with our hypothesis, during the deliberation process the baseline and gain of neural activity in decision-related PMd (29%) and M1 cells (45%) was higher when monkeys applied a hasty policy than when they behaved conservatively, but at the time of commitment the population activity was similar across blocks. Other cells (30% in PMd, 30% in M1) showed activity that increased or decreased with elapsing time until the moment of commitment. Movement-related neurons were also more active after longer decisions, as if they were influenced by the same urgency signal controlling the gain of decision-related activity. Together, these results suggest that the arm motor system receives an urgency/vigor signal that adjusts the speed-accuracy trade-off for decision-making and movement execution. Significance statement: This work addresses the neural mechanisms that control the speed-accuracy trade-off in both decisions and movements, in the kinds of dynamic situations that are typical of natural animal behavior. We found that many "decision-related" premotor and motor neurons are modulated in a time-dependent manner compatible with an "urgency" signal that

  18. Task-dependent activity of motor unit populations in feline ankle extensor muscles

    PubMed Central

    Hodson-Tole, Emma F.; Pantall, Annette; Maas, Huub; Farrell, Brad; Gregor, Robert J.; Prilutsky, Boris I.

    2012-01-01

    SUMMARY Understanding the functional significance of the morphological diversity of mammalian skeletal muscles is limited by technical difficulties of estimating the contribution of motor units with different properties to unconstrained motor behaviours. Recently developed wavelet and principal components analysis of intramuscular myoelectric signals has linked signals with lower and higher frequency contents to the use of slower and faster motor unit populations. In this study we estimated the relative contributions of lower and higher frequency signals of cat ankle extensors (soleus, medial and lateral gastrocnemii, plantaris) during level, downslope and upslope walking and the paw-shake response. This was done using the first two myoelectric signal principal components (PCI, PCII), explaining over 90% of the signal, and an angle θ, a function of PCI/PCII, indicating the relative contribution of slower and faster motor unit populations. Mean myoelectric frequencies in all walking conditions were lowest for slow soleus (234 Hz) and highest for fast gastrocnemii (307 and 330 Hz) muscles. Motor unit populations within and across the studied muscles that demonstrated lower myoelectric frequency (suggesting slower populations) were recruited during tasks and movement phases with lower mechanical demands on the ankle extensors – during downslope and level walking and in early walking stance and paw-shake phases. With increasing mechanical demands (upslope walking, mid-phase of paw-shake cycles), motor unit populations generating higher frequency signals (suggesting faster populations) contributed progressively more. We conclude that the myoelectric frequency contents within and between feline ankle extensors vary across studied motor behaviours, with patterns that are generally consistent with muscle fibre-type composition. PMID:22811250

  19. Task-dependent activity of motor unit populations in feline ankle extensor muscles.

    PubMed

    Hodson-Tole, Emma F; Pantall, Annette; Maas, Huub; Farrell, Brad; Gregor, Robert J; Prilutsky, Boris I

    2012-11-01

    Understanding the functional significance of the morphological diversity of mammalian skeletal muscles is limited by technical difficulties of estimating the contribution of motor units with different properties to unconstrained motor behaviours. Recently developed wavelet and principal components analysis of intramuscular myoelectric signals has linked signals with lower and higher frequency contents to the use of slower and faster motor unit populations. In this study we estimated the relative contributions of lower and higher frequency signals of cat ankle extensors (soleus, medial and lateral gastrocnemii, plantaris) during level, downslope and upslope walking and the paw-shake response. This was done using the first two myoelectric signal principal components (PCI, PCII), explaining over 90% of the signal, and an angle θ, a function of PCI/PCII, indicating the relative contribution of slower and faster motor unit populations. Mean myoelectric frequencies in all walking conditions were lowest for slow soleus (234 Hz) and highest for fast gastrocnemii (307 and 330 Hz) muscles. Motor unit populations within and across the studied muscles that demonstrated lower myoelectric frequency (suggesting slower populations) were recruited during tasks and movement phases with lower mechanical demands on the ankle extensors--during downslope and level walking and in early walking stance and paw-shake phases. With increasing mechanical demands (upslope walking, mid-phase of paw-shake cycles), motor unit populations generating higher frequency signals (suggesting faster populations) contributed progressively more. We conclude that the myoelectric frequency contents within and between feline ankle extensors vary across studied motor behaviours, with patterns that are generally consistent with muscle fibre-type composition. PMID:22811250

  20. 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.

  1. 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

  2. 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.

  3. The impact of pedestrian countdown signals on pedestrian–motor vehicle collisions: a quasi-experimental study

    PubMed Central

    Camden, Andi; Buliung, Ron; Rothman, Linda; Macarthur, Colin

    2011-01-01

    Objective To determine whether pedestrian countdown signals (PCS) reduce pedestrian–motor vehicle collisions in the city of Toronto, Canada. Methods A quasi-experimental study design was used to evaluate the effect of PCS on the number of pedestrian–motor vehicle collisions in the city of Toronto, from January 2000 to December 2009. Each intersection acted as its own control. We compared the number of pedestrian–motor vehicle collisions per intersection-month before and after the intervention. Stratified models were used to evaluate effect modification by pedestrian age, injury severity and location (urban vs inner suburbs). Poisson regression analysis with repeated measures (generalised estimating equations) was used to estimate the RR and 95% CI. Results The analysis included 9262 pedestrian–motor vehicle collisions at 1965 intersections. The RR of collisions after PCS installation was 1.014 (95% CI 0.958 to 1.073), indicating no statistically significant effect of PCS on collisions. There was no evidence to suggest effect modification between PCS and collisions by age, injury severity or location. Conclusion The installation of PCS at 1965 signalised intersections in Toronto did not reduce the number of pedestrian–motor vehicle collisions at these intersections. PMID:22157206

  4. A new genetic model of activity-induced Ras signaling dependent pre-synaptic plasticity in Drosophila

    PubMed Central

    Freeman, Amanda; Bowers, Mallory; Mortimer, Alysia Vrailas; Timmerman, Christina; Roux, Stephanie; Ramaswami, Mani; Sanyal, Subhabrata

    2010-01-01

    Techniques to induce activity-dependent neuronal plasticity in vivo allow the underlying signaling pathways to be studied in their biological context. Here, we demonstrate activity-induced plasticity at neuromuscular synapses of Drosophila double mutant for comatose (an NSF mutant) and Kum (a SERCA mutant), and present an analysis of the underlying signaling pathways. comt; Kum (CK) double mutants exhibit increased locomotor activity under normal culture conditions, concomitant with a larger neuromuscular junction synapse and stably elevated evoked transmitter release. The observed enhancements of synaptic size and transmitter release in CK mutants are completely abrogated by: a) reduced activity of motor neurons; b) attenuation of the Ras/ERK signaling cascade; or c) inhibition of the transcription factors Fos and CREB. all of which restrict synaptic properties to near wild type levels. Together, these results document neural activity-dependent plasticity of motor synapses in CK animals that requires Ras/ERK signaling and normal transcriptional activity of Fos and CREB. Further, novel in vivo reporters of neuronal Ras activation and Fos transcription also confirm increased signaling through a Ras/AP-1 pathway in motor neurons of CK animals, consistent with results from our genetic experiments. Thus, this study: a) provides a robust system in which to study activity-induced synaptic plasticity in vivo; b) establishes a causal link between neural activity, Ras signaling, transcriptional regulation and pre-synaptic plasticity in glutamatergic motor neurons of Drosophila larvae; and c) presents novel, genetically encoded reporters for Ras and AP-1 dependent signaling pathways in Drosophila. PMID:20193670

  5. A functional model and simulation of spinal motor pools and intrafascicular recordings of motoneuron activity in peripheral nerve

    PubMed Central

    Abdelghani, Mohamed N.; Abbas, James J.; Horch, Kenneth W.; Jung, Ranu

    2014-01-01

    Decoding motor intent from recorded neural signals is essential for the development of effective neural-controlled prostheses. To facilitate the development of online decoding algorithms we have developed a software platform to simulate neural motor signals recorded with peripheral nerve electrodes, such as longitudinal intrafascicular electrodes (LIFEs). The simulator uses stored motor intent signals to drive a pool of simulated motoneurons with various spike shapes, recruitment characteristics, and firing frequencies. Each electrode records a weighted sum of a subset of simulated motoneuron activity patterns. As designed, the simulator facilitates development of a suite of test scenarios that would not be possible with actual data sets because, unlike with actual recordings, in the simulator the individual contributions to the simulated composite recordings are known and can be methodically varied across a set of simulation runs. In this manner, the simulation tool is suitable for iterative development of real-time decoding algorithms prior to definitive evaluation in amputee subjects with implanted electrodes. The simulation tool was used to produce data sets that demonstrate its ability to capture some features of neural recordings that pose challenges for decoding algorithms. PMID:25452711

  6. Sleep Loss Activates Cellular Inflammatory Signaling

    PubMed Central

    Irwin, Michael R.; Wang, Minge; Ribeiro, Denise; Cho, Hyong Jin; Olmstead, Richard; Breen, Elizabeth Crabb; Martinez-Maza, Otoniel; Cole, Steve

    2008-01-01

    Background Accumulating evidence suggests that sleep disturbance is associated with inflammation and related disorders including cardiovascular disease, arthritis, and diabetes mellitus. This study was undertaken to test the effects of sleep loss on activation of nuclear factor (NF) -κB, a transcription factor that serves a critical role in the inflammatory signaling cascade. Methods In 14 healthy adults (7 females; 7 males), peripheral blood mononuclear cell NF-κB was repeatedly assessed, along with enumeration of lymphocyte subpopulations, in the morning after baseline sleep, partial sleep deprivation (awake from 23:00 h to 03:00 h), and recovery sleep. Results In the morning after a night of sleep loss, mononuclear cell NF-κB activation was significantly greater compared with morning levels following uninterrupted baseline or recovery sleep, in which the response was found in females but not in males. Conclusions These results identify NF-κB activation as a molecular pathway by which sleep disturbance may influence leukocyte inflammatory gene expression and the risk of inflammation-related disease. PMID:18561896

  7. 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

  8. 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

  9. Heat dissipation guides activation in signaling proteins

    PubMed Central

    Weber, Jeffrey K.; Shukla, Diwakar; Pande, Vijay S.

    2015-01-01

    Life is fundamentally a nonequilibrium phenomenon. At the expense of dissipated energy, living things perform irreversible processes that allow them to propagate and reproduce. Within cells, evolution has designed nanoscale machines to do meaningful work with energy harnessed from a continuous flux of heat and particles. As dictated by the Second Law of Thermodynamics and its fluctuation theorem corollaries, irreversibility in nonequilibrium processes can be quantified in terms of how much entropy such dynamics produce. In this work, we seek to address a fundamental question linking biology and nonequilibrium physics: can the evolved dissipative pathways that facilitate biomolecular function be identified by their extent of entropy production in general relaxation processes? We here synthesize massive molecular dynamics simulations, Markov state models (MSMs), and nonequilibrium statistical mechanical theory to probe dissipation in two key classes of signaling proteins: kinases and G-protein–coupled receptors (GPCRs). Applying machinery from large deviation theory, we use MSMs constructed from protein simulations to generate dynamics conforming to positive levels of entropy production. We note the emergence of an array of peaks in the dynamical response (transient analogs of phase transitions) that draw the proteins between distinct levels of dissipation, and we see that the binding of ATP and agonist molecules modifies the observed dissipative landscapes. Overall, we find that dissipation is tightly coupled to activation in these signaling systems: dominant entropy-producing trajectories become localized near important barriers along known biological activation pathways. We go on to classify an array of equilibrium and nonequilibrium molecular switches that harmonize to promote functional dynamics. PMID:26240354

  10. Heat dissipation guides activation in signaling proteins.

    PubMed

    Weber, Jeffrey K; Shukla, Diwakar; Pande, Vijay S

    2015-08-18

    Life is fundamentally a nonequilibrium phenomenon. At the expense of dissipated energy, living things perform irreversible processes that allow them to propagate and reproduce. Within cells, evolution has designed nanoscale machines to do meaningful work with energy harnessed from a continuous flux of heat and particles. As dictated by the Second Law of Thermodynamics and its fluctuation theorem corollaries, irreversibility in nonequilibrium processes can be quantified in terms of how much entropy such dynamics produce. In this work, we seek to address a fundamental question linking biology and nonequilibrium physics: can the evolved dissipative pathways that facilitate biomolecular function be identified by their extent of entropy production in general relaxation processes? We here synthesize massive molecular dynamics simulations, Markov state models (MSMs), and nonequilibrium statistical mechanical theory to probe dissipation in two key classes of signaling proteins: kinases and G-protein-coupled receptors (GPCRs). Applying machinery from large deviation theory, we use MSMs constructed from protein simulations to generate dynamics conforming to positive levels of entropy production. We note the emergence of an array of peaks in the dynamical response (transient analogs of phase transitions) that draw the proteins between distinct levels of dissipation, and we see that the binding of ATP and agonist molecules modifies the observed dissipative landscapes. Overall, we find that dissipation is tightly coupled to activation in these signaling systems: dominant entropy-producing trajectories become localized near important barriers along known biological activation pathways. We go on to classify an array of equilibrium and nonequilibrium molecular switches that harmonize to promote functional dynamics. PMID:26240354

  11. 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

  12. Redefining the functional roles of the gastrointestinal migrating motor complex and motilin in small bacterial overgrowth and hunger signaling.

    PubMed

    Deloose, Eveline; Tack, Jan

    2016-02-15

    During the fasting state the upper gastrointestinal tract exhibits a specific periodic migrating contraction pattern that is known as the migrating motor complex (MMC). Three different phases can be distinguished during the MMC. Phase III of the MMC is the most active of the three and can start either in the stomach or small intestine. Historically this pattern was designated to be the housekeeper of the gut since disturbances in the pattern were associated with small intestinal bacterial overgrowth; however, its role in the involvement of hunger sensations was already hinted in the beginning of the 20th century by both Cannon (Cannon W, Washburn A. Am J Physiol 29: 441-454, 1912) and Carlson (Carlson A. The Control of Hunger in Health and Disease. Chicago, IL: Univ. of Chicago Press, 1916). The discovery of motilin in 1973 shed more light on the control mechanisms of the MMC. Motilin plasma levels fluctuate together with the phases of the MMC and induce phase III contractions with a gastric onset. Recent research suggests that these motilin-induced phase III contractions signal hunger in healthy subjects and that this system is disturbed in morbidly obese patients. This minireview describes the functions of the MMC in the gut and its regulatory role in controlling hunger sensations. PMID:26660537

  13. 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

  14. PLL/PID Motor Control System by Using Time-Domain Differential Operation of PWM Signal

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Kobayashi, Fuminori

    In PLL motor speed control systems, PID-type loop filter can improve disturbance sensitivity. In this short-paper, we show that, an existing PI-type PLL/PWM motor speed controller can be supplemented with addition a difference operation including the I-counter, together with FPGA experimental result.

  15. Active voltammetric microsensors with neural signal processing.

    SciTech Connect

    Vogt, M. C.

    1998-12-11

    Many industrial and environmental processes, including bioremediation, would benefit from the feedback and control information provided by a local multi-analyte chemical sensor. For most processes, such a sensor would need to be rugged enough to be placed in situ for long-term remote monitoring, and inexpensive enough to be fielded in useful numbers. The multi-analyte capability is difficult to obtain from common passive sensors, but can be provided by an active device that produces a spectrum-type response. Such new active gas microsensor technology has been developed at Argonne National Laboratory. The technology couples an electrocatalytic ceramic-metallic (cermet) microsensor with a voltammetric measurement technique and advanced neural signal processing. It has been demonstrated to be flexible, rugged, and very economical to produce and deploy. Both narrow interest detectors and wide spectrum instruments have been developed around this technology. Much of this technology's strength lies in the active measurement technique employed. The technique involves applying voltammetry to a miniature electrocatalytic cell to produce unique chemical ''signatures'' from the analytes. These signatures are processed with neural pattern recognition algorithms to identify and quantify the components in the analyte. The neural signal processing allows for innovative sampling and analysis strategies to be employed with the microsensor. In most situations, the whole response signature from the voltammogram can be used to identify, classify, and quantify an analyte, without dissecting it into component parts. This allows an instrument to be calibrated once for a specific gas or mixture of gases by simple exposure to a multi-component standard rather than by a series of individual gases. The sampled unknown analytes can vary in composition or in concentration, the calibration, sensing, and processing methods of these active voltammetric microsensors can detect, recognize, and

  16. Centaurin-alpha1 and KIF13B kinesin motor protein interaction in ARF6 signalling.

    PubMed

    Kanamarlapudi, V

    2005-12-01

    The ARF (ADP-ribosylation factor) family of small GTPases regulate intracellular membrane trafficking by cycling between an inactive GDP- and an active GTP-bound form. Among the six known mammalian ARFs (ARF1-ARF6), ARF6 is the least conserved and plays critical roles in membrane trafficking and cytoskeletal dynamics near the cell surface. Since ARFs have undetectable levels of intrinsic GTP binding and hydrolysis, they are totally dependent on extrinsic GEFs (guanine nucleotide-exchange factors) for GTP binding and GAPs (GTPase-activating proteins) for GTP hydrolysis. We have recently isolated a novel KIF (kinesin) motor protein (KIF13B) that binds to centaurin-alpha1, an ARF6GAP that binds to the second messenger PIP3 [PtdIns(3,4,5)P3]. KIFs transport intracellular vesicles and recognize their cargo by binding to proteins (receptors) localized on the surface of the cargo vesicles. Identification of centaurin-alpha1 as a KIF13B interactor suggests that KIF13B may transport ARF6 and/or PIP3 using centaurin-alpha1 as its receptor. This paper reviews the studies carried out to assess the interaction and regulation of centaurin-alpha1 by KIF13B. PMID:16246098

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. Oscillations in the power spectra of motor unit signals caused by refractoriness variations

    NASA Astrophysics Data System (ADS)

    Hu, X. L.; Tong, K. Y.; Hung, L. K.

    2004-09-01

    The refractory period of a motor unit is an important mechanism that regulates the motor unit firing, and its variation has been found in many physiological cases. In this study, a new observation that an increase in the motor unit refractoriness results in an enhancement of oscillations, or ripple effects, in the motor unit output power density spectra (PDS) has been identified and studied. The effects of the refractoriness variation on the PDS of motor unit firing were investigated on three levels: theoretical modeling, simulation and electromyographic (EMG) experimentation on human subjects. Both theoretical modeling and simulation showed the enhanced oscillations, ripple effects, in MUAPT PDS, given the increase in the refractoriness. It was also found that the extent of the increment in output PDS oscillation could be related to the motor unit size and the mean firing rate of the stimulation. A needle EMG experiment on biceps brachii muscles of five healthy human subjects was carried out during isometric contraction at 20% maximum voluntary contraction (MVC) for 20 s with a fatigue effort proceeded by MVC. The increased oscillations in the PDS of the real MUAPTs were observed with the rising of the motor unit refractoriness due to fatigue. The study gives new information for EMG spectra interpretation, and also provides a potential method for accessing neuromuscular transmission failure (NTF) due to fatigue during voluntary contraction.

  3. New Constitutively Active Phytochromes Exhibit Light-Independent Signaling Activity.

    PubMed

    Jeong, A-Reum; Lee, Si-Seok; Han, Yun-Jeong; Shin, Ah-Young; Baek, Ayoung; Ahn, Taeho; Kim, Min-Gon; Kim, Young Soon; Lee, Keun Woo; Nagatani, Akira; Kim, Jeong-Il

    2016-08-01

    Plant phytochromes are photoreceptors that mediate a variety of photomorphogenic responses. There are two spectral photoisomers, the red light-absorbing Pr and far-red light-absorbing Pfr forms, and the photoreversible transformation between the two forms is important for the functioning of phytochromes. In this study, we isolated a Tyr-268-to-Val mutant of Avena sativa phytochrome A (AsYVA) that displayed little photoconversion. Interestingly, transgenic plants of AsYVA showed light-independent phytochrome signaling with a constitutive photomorphogenic (cop) phenotype that is characterized by shortened hypocotyls and open cotyledons in the dark. In addition, the corresponding Tyr-303-to-Val mutant of Arabidopsis (Arabidopsis thaliana) phytochrome B (AtYVB) exhibited nuclear localization and interaction with phytochrome-interacting factor 3 (PIF3) independently of light, conferring a constitutive photomorphogenic development to its transgenic plants, which is comparable to the first constitutively active version of phytochrome B (YHB; Tyr-276-to-His mutant). We also found that chromophore ligation was required for the light-independent interaction of AtYVB with PIF3. Moreover, we demonstrated that AtYVB did not exhibit phytochrome B activity when it was localized in the cytosol by fusion with the nuclear export signal and that AsYVA exhibited the full activity of phytochrome A when localized in the nucleus by fusion with the nuclear localization signal. Furthermore, the corresponding Tyr-269-to-Val mutant of Arabidopsis phytochrome A (AtYVA) exhibited similar cop phenotypes in transgenic plants to AsYVA. Collectively, these results suggest that the conserved Tyr residues in the chromophore-binding pocket play an important role during the Pr-to-Pfr photoconversion of phytochromes, providing new constitutively active alleles of phytochromes by the Tyr-to-Val mutation. PMID:27325667

  4. Active transport improves the precision of linear long distance molecular signalling

    NASA Astrophysics Data System (ADS)

    Godec, Aljaž; Metzler, Ralf

    2016-09-01

    Molecular signalling in living cells occurs at low copy numbers and is thereby inherently limited by the noise imposed by thermal diffusion. The precision at which biochemical receptors can count signalling molecules is intimately related to the noise correlation time. In addition to passive thermal diffusion, messenger RNA and vesicle-engulfed signalling molecules can transiently bind to molecular motors and are actively transported across biological cells. Active transport is most beneficial when trafficking occurs over large distances, for instance up to the order of 1 metre in neurons. Here we explain how intermittent active transport allows for faster equilibration upon a change in concentration triggered by biochemical stimuli. Moreover, we show how intermittent active excursions induce qualitative changes in the noise in effectively one-dimensional systems such as dendrites. Thereby they allow for significantly improved signalling precision in the sense of a smaller relative deviation in the concentration read-out by the receptor. On the basis of linear response theory we derive the exact mean field precision limit for counting actively transported molecules. We explain how intermittent active excursions disrupt the recurrence in the molecular motion, thereby facilitating improved signalling accuracy. Our results provide a deeper understanding of how recurrence affects molecular signalling precision in biological cells and novel medical-diagnostic devices.

  5. 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

  6. 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

  7. 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 ...

  8. 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

  9. 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…

  10. 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.

  11. 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…

  12. Speech motor learning changes the neural response to both auditory and somatosensory signals

    PubMed Central

    Ito, Takayuki; Coppola, Joshua H.; Ostry, David J.

    2016-01-01

    In the present paper, we present evidence for the idea that speech motor learning is accompanied by changes to the neural coding of both auditory and somatosensory stimuli. Participants in our experiments undergo adaptation to altered auditory feedback, an experimental model of speech motor learning which like visuo-motor adaptation in limb movement, requires that participants change their speech movements and associated somatosensory inputs to correct for systematic real-time changes to auditory feedback. We measure the sensory effects of adaptation by examining changes to auditory and somatosensory event-related responses. We find that adaptation results in progressive changes to speech acoustical outputs that serve to correct for the perturbation. We also observe changes in both auditory and somatosensory event-related responses that are correlated with the magnitude of adaptation. These results indicate that sensory change occurs in conjunction with the processes involved in speech motor adaptation. PMID:27181603

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. The effect of involuntary motor activity on myoelectric pattern recognition: a case study with chronic stroke patients

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Li, Yun; Chen, Xiang; Li, Guanglin; Zev Rymer, William; Zhou, Ping

    2013-08-01

    Objective. This study investigates the effect of the involuntary motor activity of paretic-spastic muscles on the classification of surface electromyography (EMG) signals. Approach. Two data collection sessions were designed for 8 stroke subjects to voluntarily perform 11 functional movements using their affected forearm and hand at relatively slow and fast speeds. For each stroke subject, the degree of involuntary motor activity present in the voluntary surface EMG recordings was qualitatively described from such slow and fast experimental protocols. Myoelectric pattern recognition analysis was performed using different combinations of voluntary surface EMG data recorded from the slow and fast sessions. Main results. Across all tested stroke subjects, our results revealed that when involuntary surface EMG is absent or present in both the training and testing datasets, high accuracies (>96%, >98%, respectively, averaged over all the subjects) can be achieved in the classification of different movements using surface EMG signals from paretic muscles. When involuntary surface EMG was solely involved in either the training or testing datasets, the classification accuracies were dramatically reduced (<89%, <85%, respectively). However, if both the training and testing datasets contained EMG signals with the presence and absence of involuntary EMG interference, high accuracies were still achieved (>97%). Significance. The findings of this study can be used to guide the appropriate design and implementation of myoelectric pattern recognition based systems or devices toward promoting robot-aided therapy for stroke rehabilitation.

  3. Targeted, activity-dependent spinal stimulation produces long-lasting motor recovery in chronic cervical spinal cord injury

    PubMed Central

    McPherson, Jacob G.; Miller, Robert R.; Perlmutter, Steve I.

    2015-01-01

    Use-dependent movement therapies can lead to partial recovery of motor function after neurological injury. We attempted to improve recovery by developing a neuroprosthetic intervention that enhances movement therapy by directing spike timing-dependent plasticity in spared motor pathways. Using a recurrent neural–computer interface in rats with a cervical contusion of the spinal cord, we synchronized intraspinal microstimulation below the injury with the arrival of functionally related volitional motor commands signaled by muscle activity in the impaired forelimb. Stimulation was delivered during physical retraining of a forelimb behavior and throughout the day for 3 mo. Rats receiving this targeted, activity-dependent spinal stimulation (TADSS) exhibited markedly enhanced recovery compared with animals receiving targeted but open-loop spinal stimulation and rats receiving physical retraining alone. On a forelimb reach and grasp task, TADSS animals recovered 63% of their preinjury ability, more than two times the performance level achieved by the other therapy groups. Therapeutic gains were maintained for 3 additional wk without stimulation. The results suggest that activity-dependent spinal stimulation can induce neural plasticity that improves behavioral recovery after spinal cord injury. PMID:26371306

  4. Targeted, activity-dependent spinal stimulation produces long-lasting motor recovery in chronic cervical spinal cord injury.

    PubMed

    McPherson, Jacob G; Miller, Robert R; Perlmutter, Steve I

    2015-09-29

    Use-dependent movement therapies can lead to partial recovery of motor function after neurological injury. We attempted to improve recovery by developing a neuroprosthetic intervention that enhances movement therapy by directing spike timing-dependent plasticity in spared motor pathways. Using a recurrent neural-computer interface in rats with a cervical contusion of the spinal cord, we synchronized intraspinal microstimulation below the injury with the arrival of functionally related volitional motor commands signaled by muscle activity in the impaired forelimb. Stimulation was delivered during physical retraining of a forelimb behavior and throughout the day for 3 mo. Rats receiving this targeted, activity-dependent spinal stimulation (TADSS) exhibited markedly enhanced recovery compared with animals receiving targeted but open-loop spinal stimulation and rats receiving physical retraining alone. On a forelimb reach and grasp task, TADSS animals recovered 63% of their preinjury ability, more than two times the performance level achieved by the other therapy groups. Therapeutic gains were maintained for 3 additional wk without stimulation. The results suggest that activity-dependent spinal stimulation can induce neural plasticity that improves behavioral recovery after spinal cord injury. PMID:26371306

  5. 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…

  6. Development of response activation and inhibition in a selective stop-signal task.

    PubMed

    van de Laar, Maria C; van den Wildenberg, Wery P M; van Boxtel, Geert J M; van der Molen, Maurits W

    2014-10-01

    To gain more insight into the development of action control, the current brain potential study examined response selection, activation, and selective inhibition during choice- and stop-signal processing in three age groups (8-, 12-, and 21-year-olds). Results revealed that age groups differed in the implementation of proactive control; children slowed their go response and showed reduced cortical motor output compared to adults. On failed inhibition trials, children were less able than adults to suppress muscle output resulting in increased partial-inhibition rates. On invalid stop trials, all age groups initially activated, subsequently inhibited, and then reactivated the go response. Yet, children were less efficient in implementing this strategy. Then, older children recruit motor responses to a greater extent than younger children and adults, which reduced the efficiency of implementing response inhibition and proactive control. The results are discussed in relation to current notions of developmental change in proactive and reactive action control. PMID:25014630

  7. 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

  8. 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

  9. Signal, Noise, and Variation in Neural and Sensory-Motor Latency.

    PubMed

    Lee, Joonyeol; Joshua, Mati; Medina, Javier F; Lisberger, Stephen G

    2016-04-01

    Analysis of the neural code for sensory-motor latency in smooth pursuit eye movements reveals general principles of neural variation and the specific origin of motor latency. The trial-by-trial variation in neural latency in MT comprises a shared component expressed as neuron-neuron latency correlations and an independent component that is local to each neuron. The independent component arises heavily from fluctuations in the underlying probability of spiking, with an unexpectedly small contribution from the stochastic nature of spiking itself. The shared component causes the latency of single-neuron responses in MT to be weakly predictive of the behavioral latency of pursuit. Neural latency deeper in the motor system is more strongly predictive of behavioral latency. A model reproduces both the variance of behavioral latency and the neuron-behavior latency correlations in MT if it includes realistic neural latency variation, neuron-neuron latency correlations in MT, and noisy gain control downstream of MT. PMID:26971946

  10. 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