03907nas a2200361   4500008004100000022001400041245007800055210006900133260001300202300001400215490000800229520287700237653001203114653001303126653002503139653001003164653002603174653001303200653001303213653000903226653001803235653002403253653000903277653002503286653001603311100001303327700001303340700001303353700002103366700002203387700002403409856011203433       2024                        eng d  a1469-779300aMotor learning changes the axon initial segment of the spinal motoneuron.0 aMotor learning changes the axon initial segment of the spinal mo  c2024 May  a2107-21260 v6023 a<p>We are studying the mechanisms of H-reflex operant conditioning, a simple form of learning. Modelling studies in the literature and our previous data suggested that changes in the axon initial segment (AIS) might contribute. To explore this, we used blinded quantitative histological and immunohistochemical methods to study in adult rats the impact of H-reflex conditioning on the AIS of the spinal motoneuron that produces the reflex. Successful, but not unsuccessful, H-reflex up-conditioning was associated with greater AIS length and distance from soma; greater length correlated with greater H-reflex increase. Modelling studies in the literature suggest that these increases may increase motoneuron excitability, supporting the hypothesis that they may contribute to H-reflex increase. Up-conditioning did not affect AIS ankyrin G (AnkG) immunoreactivity (IR), p-p38 protein kinase IR, or GABAergic terminals. Successful, but not unsuccessful, H-reflex down-conditioning was associated with more GABAergic terminals on the AIS, weaker AnkG-IR, and stronger p-p38-IR. More GABAergic terminals and weaker AnkG-IR correlated with greater H-reflex decrease. These changes might potentially contribute to the positive shift in motoneuron firing threshold underlying H-reflex decrease; they are consistent with modelling suggesting that sodium channel change may be responsible. H-reflex down-conditioning did not affect AIS dimensions. This evidence that AIS plasticity is associated with and might contribute to H-reflex conditioning adds to evidence that motor learning involves both spinal and brain plasticity, and both neuronal and synaptic plasticity. AIS properties of spinal motoneurons are likely to reflect the combined influence of all the motor skills that share these motoneurons. KEY POINTS: Neuronal action potentials normally begin in the axon initial segment (AIS). AIS plasticity affects neuronal excitability in development and disease. Whether it does so in learning is unknown. Operant conditioning of a spinal reflex, a simple learning model, changes the rat spinal motoneuron AIS. Successful, but not unsuccessful, H-reflex up-conditioning is associated with greater AIS length and distance from soma. Successful, but not unsuccessful, down-conditioning is associated with more AIS GABAergic terminals, less ankyrin G, and more p-p38 protein kinase. The associations between AIS plasticity and successful H-reflex conditioning are consistent with those between AIS plasticity and functional changes in development and disease, and with those predicted by modelling studies in the literature. Motor learning changes neurons and synapses in spinal cord and brain. Because spinal motoneurons are the final common pathway for behaviour, their AIS properties probably reflect the combined impact of all the behaviours that use these motoneurons.</p>10aAnimals10aAnkyrins10aAxon Initial Segment10aAxons10aConditioning, Operant10aH-Reflex10aLearning10aMale10aMotor Neurons10aNeuronal Plasticity10aRats10aRats, Sprague-Dawley10aSpinal Cord1 aWang, Yu1 aChen, Yi1 aChen, Lu1 aHerron, Bruce, J1 aChen, Xiang, Yang1 aWolpaw, Jonathan, R  uhttps://neurotechcenter.org/publications/2024/motor-learning-changes-axon-initial-segment-spinal-motoneuron02675nas a2200325   4500008004100000022001400041245010000055210006900155260001200224300001200236490000800248520178700256653001202043653002602055653001102081653001302092653001302105653001502118653000902133653000902142653002502151653002502176100001302201700001302214700001902227700001302246700002102259700002102280856004802301       2014                        eng d  a1522-159800aLocomotor impact of beneficial or nonbeneficial H-reflex conditioning after spinal cord injury.0 aLocomotor impact of beneficial or nonbeneficial Hreflex conditio  c03/2014  a1249-580 v1113 aWhen new motor learning changes neurons and synapses in the spinal cord, it may affect previously learned behaviors that depend on the same spinal neurons and synapses. To explore these effects, we used operant conditioning to strengthen or weaken the right soleus H-reflex pathway in rats in which a right spinal cord contusion had impaired locomotion. When up-conditioning increased the H-reflex, locomotion improved. Steps became longer, and step-cycle asymmetry (i.e., limping) disappeared. In contrast, when down-conditioning decreased the H-reflex, locomotion did not worsen. Steps did not become shorter, and asymmetry did not increase. Electromyographic and kinematic analyses explained how H-reflex increase improved locomotion and why H-reflex decrease did not further impair it. Although the impact of up-conditioning or down-conditioning on the H-reflex pathway was still present during locomotion, only up-conditioning affected the soleus locomotor burst. Additionally, compensatory plasticity apparently prevented the weaker H-reflex pathway caused by down-conditioning from weakening the locomotor burst and further impairing locomotion. The results support the hypothesis that the state of the spinal cord is a "negotiated equilibrium" that serves all the behaviors that depend on it. When new learning changes the spinal cord, old behaviors undergo concurrent relearning that preserves or improves their key features. Thus, if an old behavior has been impaired by trauma or disease, spinal reflex conditioning, by changing a specific pathway and triggering a new negotiation, may enable recovery beyond that achieved simply by practicing the old behavior. Spinal reflex conditioning protocols might complement other neurorehabilitation methods and enhance recovery.10aAnimals10aConditioning, Operant10aFemale10aH-Reflex10aLearning10aLocomotion10aMale10aRats10aRats, Sprague-Dawley10aSpinal Cord Injuries1 aChen, Yi1 aChen, Lu1 aLiu, Rongliang1 aWang, Yu1 aChen, Xiang Yang1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/2437128802577nas a2200301   4500008004100000022001400041245010600055210006900161260001200230300001200242490000800254520171500262653001201977653002601989653002102015653001102036653001502047653000902062653002502071653001202096653001402108653001602122100002402138700002102162700002102183700002302204856004802227       2014                        eng d  a1522-146600aLong-term recording of external urethral sphincter EMG activity in unanesthetized, unrestrained rats.0 aLongterm recording of external urethral sphincter EMG activity i  c08/2014  aF485-970 v3073 a<p>The external urethral sphincter muscle (EUS) plays an important role in urinary function and often contributes to urinary dysfunction. EUS study would benefit from methodology for longitudinal recording of electromyographic activity (EMG) in unanesthetized animals, but this muscle is a poor substrate for chronic intramuscular electrodes, and thus the required methodology has not been available. We describe a method for long-term recording of EUS EMG by implantation of fine wires adjacent to the EUS that are secured to the pubic bone. Wires pass subcutaneously to a skull-mounted plug and connect to the recording apparatus by a flexible cable attached to a commutator. A force transducer-mounted cup under a metabolic cage collected urine, allowing recording of EUS EMG and voided urine weight without anesthesia or restraint. Implant durability permitted EUS EMG recording during repeated (up to 3 times weekly) 24-h sessions for more than 8 wk. EMG and voiding properties were stable over weeks 2-8. The degree of EUS phasic activity (bursting) during voiding was highly variable, with an average of 25% of voids not exhibiting bursting. Electrode implantation adjacent to the EUS yielded stable EMG recordings over extended periods and eliminated the confounding effects of anesthesia, physical restraint, and the potential for dislodgment of the chronically implanted intramuscular electrodes. These results show that micturition in unanesthetized, unrestrained rats is usually, but not always, associated with EUS bursting. This methodology is applicable to studying EUS behavior during progression of gradually evolving disease and injury models and in response to therapeutic interventions.</p>10aAnimals10aElectrodes, Implanted10aElectromyography10aFemale10aPubic Bone10aRats10aRats, Sprague-Dawley10aUrethra10aUrination10aUrodynamics1 aLaPallo, Brandon, K1 aWolpaw, Jonathan1 aChen, Xiang Yang1 aCarp, Jonathan, S.  uhttp://www.ncbi.nlm.nih.gov/pubmed/2499089502364nas a2200217   4500008004100000022001400041245011800055210006900173260001200242300001800254490000700272520171000279653000901989653001901998100001302017700001302030700001302043700002102056700002102077856004802098       2011                        eng d  a1529-240100aOperant conditioning of rat soleus H-reflex oppositely affects another H-reflex and changes locomotor kinematics.0 aOperant conditioning of rat soleus Hreflex oppositely affects an  c08/2011  a11370–113750 v313 aH-reflex conditioning is a model for studying the plasticity associated with a new motor skill. We are exploring its effects on other reflexes and on locomotion. Rats were implanted with EMG electrodes in both solei (SOL(R) and SOL(L)) and right quadriceps (QD(R)), and stimulating cuffs on both posterior tibial (PT) nerves and right posterior femoral nerve. When SOL(R) EMG remained in a defined range, PT(R) stimulation just above M-response threshold elicited the SOL(R) H-reflex. Analogous procedures elicited the QD(R) and SOL(L) H-reflexes. After a control period, each rat was exposed for 50 d to a protocol that rewarded SOL(R) H-reflexes that were above (HRup rats) or below (HRdown rats) a criterion. HRup conditioning increased the SOL(R) H-reflex to 214 ± 37% (mean ± SEM) of control (p = 0.02) and decreased the QD(R) H-reflex to 71 ± 26% (p = 0.06). HRdown conditioning decreased the SOL(R) H-reflex to 69 ± 2% (p < 0.001) and increased the QD(R) H-reflex to 121 ± 7% (p = 0.02). These changes remained during locomotion. The SOL(L) H-reflex did not change. During the stance phase of locomotion, ankle plantarflexion increased in HRup rats and decreased in HRdown rats, hip extension did the opposite, and hip height did not change. The plasticity that changes the QD(R) H-reflex and locomotor kinematics may be inevitable (i.e., reactive) due to the ubiquity of activity-dependent CNS plasticity, and/or necessary (i.e., compensatory) to preserve other behaviors (e.g., locomotion) that would otherwise be disturbed by the change in the SOL(R) H-reflex pathway. The changes in joint angles, coupled with the preservation of hip height, suggest that compensatory plasticity did occur.10aRats10aSprague-Dawley1 aChen, Yi1 aChen, Lu1 aWang, Yu1 aWolpaw, Jonathan1 aChen, Xiang Yang  uhttp://www.ncbi.nlm.nih.gov/pubmed/2181369602708nas a2200373   4500008004100000022001400041245010900055210006900164260001200233300001100245490000600256520162400262653002201886653001201908653001001920653001801930653002501948653001501973653002901988653000902017653002402026653001702050653001202067653000902079653002502088653004102113653002602154100001602180700002302196700001902219700002802238700002002266856004802286       2006                        eng d  a1557-170X00aAnalysis of the correlation between local field potentials and neuronal firing rate in the motor cortex.0 aAnalysis of the correlation between local field potentials and n  c09/2006  a6185-80 v13 a<p><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">Neuronal firing rate has been the signal of choice for invasive motor&nbsp;</span><span class="highlight" style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">brain</span><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">&nbsp;machine&nbsp;</span><span class="highlight" style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">interfaces</span><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">&nbsp;(BMI). The use of local field potentials (LFP) in BMI experiments may provide additional dendritic information about movement intent and may improve performance. Here we study the time-varying amplitude modulated relationship between local field potentials (LFP) and single unit activity (SUA) in the motor cortex. We record LFP and SUA in the primary motor cortex of rats trained to perform a lever pressing task, and evaluate the correlation between pairs of peri-event time histograms (PETH) and movement evoked local field potentials (mEP) at the same electrode. Three different correlation coefficients were calculated and compared between the neuronal PETH and the magnitude and power of the mEP. Correlation as high as 0.7 for some neurons occurred between the PETH and the mEP magnitude. As expected, the correlations between the single trial LFP and SUV are much lower due to the inherent variability of both signals.</span></p>10aAction Potentials10aAnimals10aBrain10aBrain Mapping10aElectric Stimulation10aElectrodes10aEvoked Potentials, Motor10aMale10aModels, Statistical10aMotor Cortex10aNeurons10aRats10aRats, Sprague-Dawley10aSignal Processing, Computer-Assisted10aSynaptic Transmission1 aWang, Yiwen1 aSanchez, Justin, C1 aPrincipe, Jose1 aMitzelfelt, Jeremiah, D1 aGunduz, Aysegul  uhttp://www.ncbi.nlm.nih.gov/pubmed/1794674502917nas a2200265   4500008004100000022001400041245009700055210006900152260001200221300001000233490000800243520213200251653002202383653001202405653002102417653001302438653001802451653002102469653000902490653004102499100001902540700002302559700002102582856004802603       2002                        eng d  a0165-027000aTemporal transformation of multiunit activity improves identification of single motor units.0 aTemporal transformation of multiunit activity improves identific  c02/2002  a87-980 v1143 a<p><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">This report describes a temporally based method for identifying repetitive firing of motor units. This&nbsp;</span><span class="highlight" style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">approach</span><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">&nbsp;is ideally suited to spike trains with negative serially correlated inter-spike intervals (ISIs). It can also be applied to spike trains in which ISIs exhibit little serial correlation if their coefficient of variation (COV) is sufficiently low. Using a novel application of the Hough transform, this method (i.e. the modified Hough transform (MHT)) maps motor unit action potential (MUAP) firing times into a feature space with ISI and offset (defined as the latency from an arbitrary starting time to the first MUAP in the train) as dimensions. Each MUAP firing time corresponds to a pattern in the feature space that represents all possible MUAP trains with a firing at that time. Trains with stable ISIs produce clusters in the feature space, whereas randomly firing trains do not. The MHT provides a direct estimate of mean firing rate and its variability for the entire data segment, even if several individual MUAPs are obscured by firings from other motor units. Addition of this method to a shape-based classification&nbsp;</span><span class="highlight" style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">approach</span><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">&nbsp;markedly improved rejection of false positives using simulated data and identified spike trains in whole muscle electromyographic recordings from rats. The relative independence of the MHT from the need to correctly classify individual firings permits a global description of stable repetitive firing behavior that is complementary to shape-based approaches to MUAP classification.</span></p>10aAction Potentials10aAnimals10aElectromyography10aH-Reflex10aMotor Neurons10aMuscle, Skeletal10aRats10aSignal Processing, Computer-Assisted1 aSchalk, Gerwin1 aCarp, Jonathan, S.1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/1185004301682nas a2200229   4500008004100000022001400041245010100055210006900156260001200225300001400237490000800251520101200259653002101271653001301292653001301305653001101318653002501329653000901354100002101363700002101384856004701405       1995                        eng d  a0304-394000aOperantly conditioned plasticity and circadian rhythm in rat H-reflex are independent phenomena.0 aOperantly conditioned plasticity and circadian rhythm in rat Hre  c08/1995  a109–1120 v1953 aRecent studies indicate that rats can increase or decrease H-reflex amplitude in response to an operant conditioning paradigm. In addition, rats also display a circadian rhythm in H-reflex amplitude. As part of the development of H-reflex conditioning in the rat as a new model for defining the plasticity underlying a simple form of learning, this study examined the relationship in the rat between operantly conditioned H-reflex change and the H-reflex circadian rhythm. When H-reflex amplitude increased or decreased in response to the operant conditioning program, its circadian rhythm showed no changes in phase and minimal change in amplitude. Furthermore, animals did not alter daily performance schedule so as to use the rhythm to increase reward probability. Thus, in the rat, H-reflex operant conditioning and the H-reflex circadian rhythm appear to be independent phenomena. The circadian rhythm should not be a significant complicating factor in studies of operantly conditioned H-reflex change.10acircadian rhythm10aH-Reflex10aLearning10aMemory10aoperant conditioning10aRats1 aChen, Xiang Yang1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/7478262