NeuroMeasure: A Software Package for Quantification of Cortical Motor Maps Using Frameless Stereotaxic Transcranial Magnetic Stimulation.

Unlabelled: The recent enhanced sophistication of non-invasive mapping of the human motor cortex using MRI-guided Transcranial Magnetic Stimulation (TMS) techniques, has not been matched by refinement of methods for generating maps from motor evoked potential (MEP) data, or in quantifying map features. This is despite continued interest in understanding cortical reorganization for natural adaptive processes such as skill learning, or in the case of motor recovery, such as after lesion affecting the corticospinal system. With the observation that TMS-MEP map calculation and quantification methods vary, and that no readily available commercial or free software exists, we sought to establish and make freely available a comprehensive software package that advances existing methods, and could be helpful to scientists and clinician-researchers.

Clinical improvement with intensive robot-assisted arm training in chronic stroke is unchanged by supplementary tDCS.

Background: Intensive robot-assisted arm training in the chronic phase of stroke recovery can lead to clinical improvement. Combinatorial therapeutic approaches are sought to further optimize stroke recovery. Transcranial direct current stimulation (tDCS) is one candidate to combine with robotic training, as transient increases in excitability and improvements in motor behavior have separately been reported.

Robotic Arm Rehabilitation in Chronic Stroke Patients With Aphasia May Promote Speech and Language Recovery (but Effect Is Not Enhanced by Supplementary tDCS).

This study aimed to determine the extent to which robotic arm rehabilitation for chronic stroke may promote recovery of speech and language function in individuals with aphasia. We prospectively enrolled 17 individuals from a hemiparesis rehabilitation study pairing intensive robot assisted therapy with sham or active tDCS and evaluated their speech ( = 17) and language ( = 9) performance before and after a 12-week (36 session) treatment regimen. Performance changes were evaluated with paired -tests comparing pre- and post-test measures.

Muscle length effect on corticospinal excitability during maximal concentric, isometric and eccentric contractions of the knee extensors.

What is the central question of this study? Does sensory input from peripheral mechanoreceptors determine the specific neural control of eccentric contractions? How corticospinal excitability (i.e. muscle responses to motor cortex stimulation) is affected by muscle length has never been investigated during eccentric contractions.

Improved grasp function with transcranial direct current stimulation in chronic spinal cord injury.

Background: Recovering hand function has important implications for improving independence of patients with tetraplegia after traumatic spinal cord injury (SCI). Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique that has potential to improve motor function.

Objective: To investigate the effects of one session of 1 mA, 2 mA, and sham anodal tDCS (a-tDCS) in the upper extremity (hand) motor performance (grasp and lease) in patients with chronic cervical SCI.

Optimising conservative management of chronic low back pain: study protocol for a randomised controlled trial.

Background: Lower back pain is a global health issue affecting approximately 80% of people at some stage in their life. The current literature suggests that any exercise is beneficial for reducing back pain. However, as pain is a subjective evaluation and physical deficits are evident in low back pain, using it as the sole outcome measure to evaluate superiority of an exercise protocol for low back pain treatment is insufficient.

Construction and Evaluation of Rodent-Specific rTMS Coils.

Rodent models of transcranial magnetic stimulation (TMS) play a crucial role in aiding the understanding of the cellular and molecular mechanisms underlying TMS induced plasticity. Rodent-specific TMS have previously been used to deliver focal stimulation at the cost of stimulus intensity (12 mT). Here we describe two novel TMS coils designed to deliver repetitive TMS (rTMS) at greater stimulation intensities whilst maintaining spatial resolution.

Repetitive Transcranial Magnetic Stimulation of the Brain: Mechanisms from Animal and Experimental Models.

Since the development of transcranial magnetic stimulation (TMS) in the early 1980s, a range of repetitive TMS (rTMS) protocols are now available to modulate neuronal plasticity in clinical and non-clinical populations. However, despite the wide application of rTMS in humans, the mechanisms underlying rTMS-induced plasticity remain uncertain. Animal and in vitro models provide an adjunct method of investigating potential synaptic and non-synaptic mechanisms of rTMS-induced plasticity.

Stroke subtype and motor impairment influence contralesional excitability.

Objective: The nonlesioned motor cortex (M1NL) is thought to be hyperexcitable in patients with subacute or chronic stroke and offers a promising therapeutic target. However, whether M1NL excitability behaves the same for subcortical and cortical strokes is unknown. The aim of the present study was to determine whether cortical, or purely subcortical, strokes have a different effect on M1NL excitability.

Interactive effects of GPI stimulation and levodopa on postural control in Parkinson's disease.

Introduction: Postural instability is a major source of disability in idiopathic Parkinson's disease (IPD). Deep brain stimulation of the globus pallidus internus (GPI-DBS) improves clinician-rated balance control but there have been few quantitative studies of its interactive effects with levodopa (L-DOPA). The purpose of this study was to compare the short-term and interactive effects of GPI-DBS and L-DOPA on objective measures of postural stability in patients with longstanding IPD.

Evidence for an excitatory GABAA response in human motor cortex in idiopathic generalised epilepsy.

Purpose: Impaired GABAergic inhibition has been implicated in the pathophysiology of epilepsy. The possibility of a paradoxical excitatory effect of GABA in epilepsy has been suggested, but has not been investigated in vivo. We investigated pre- and post-synaptic GABAergic mechanisms in patients with idiopathic generalised epilepsy (IGE).

Augmenting Plasticity Induction in Human Motor Cortex by Disinhibition Stimulation.

Cellular studies showed that disinhibition, evoked pharmacologically or by a suitably timed priming stimulus, can augment long-term plasticity (LTP) induction. We demonstrated previously that transcranial magnetic stimulation evokes a period of presumably GABA(B)ergic late cortical disinhibition (LCD) in human primary motor cortex (M1). Here, we hypothesized that, in keeping with cellular studies, LCD can augment LTP-like plasticity in humans.

Movement-generated afference paired with transcranial magnetic stimulation: an associative stimulation paradigm.

Background: A peripheral nerve stimulus can enhance or suppress the evoked response to transcranial magnetic stimulation (TMS) depending on the latency of the preceding peripheral nerve stimulation (PNS) pulse. Similarly, somatosensory afference from the passively moving limb can transiently alter corticomotor excitability, in a phase-dependent manner. The repeated association of PNS with TMS is known to modulate corticomotor excitability; however, it is unknown whether repeated passive-movement associative stimulation (MAS) has similar effects.

Modulation of corticomotor excitability after maximal or sustainable-rate repetitive finger movement is impaired in Parkinson's disease and is reversed by levodopa.

Objectives: In healthy subjects, fatiguing exercises induce a period of post-exercise corticomotor depression (PECD) that is absent in Parkinson's disease (PD). Our objective is to determine the time-course of corticomotor excitability changes following a 10-s repetitive index finger flexion-extension task performed at maximal voluntary rate (MVR) and a slower sustainable rate (MSR) in PD patients OFF and ON levodopa.

Methods: In 11 PD patients and 10 healthy age-matched controls, motor evoked potentials (MEPs) were recorded from the extensor indicis proprius (EIP) and first dorsal interosseous (FDI) muscles of the dominant arm immediately after the two tasks and at 2-min intervals for 10 min.

Improved motor performance in chronic spinal cord injury following upper-limb robotic training.

Background: Recovering upper-limb motor function has important implications for improving independence of patients with tetraplegia after traumatic spinal cord injury (SCI).

Objective: To evaluate the feasibility, safety and effectiveness of robotic-assisted training of upper limb in a chronic SCI population.

Methods: A total of 10 chronic tetraplegic SCI patients (C4 to C6 level of injury, American Spinal Injury Association Impairment Scale, A to D) participated in a 6-week wrist-robot training protocol (1 hour/day 3 times/week).

Clinical and posturographic correlates of falling in Parkinson's disease.

Various clinical tests and balance scales have been used to assess postural stability and the risk of falling in patients with idiopathic Parkinson's disease (IPD). Quantitative posturography allows a more objective assessment but the findings in previous studies have been inconsistent and few studies have investigated which posturographic measures correlate best with a history of falling. The purpose of this study was to determine the efficacy of clinical tests, balance scales, and stable-platform posturography in detecting postural instability and discriminating between fallers and non-fallers in a home-dwelling PD cohort.

Inverse correlation between resting motor threshold and corticomotor excitability after static magnetic stimulation of human motor cortex.

Background: High-strength static magnetic field stimulation (SMS) results in a period of reduced corticomotor excitability that may be mediated through a decrease in membrane excitability.

Objective: As resting motor threshold (RMT) is thought to reflect membrane excitability, we hypothesized that SMS may increase RMT and that there would be an inverse relationship between RMT and motor-evoked potential (MEP) amplitude.

Methods: Ten healthy subjects (aged 20-29; 4 females) participated in a double-blinded crossover design comparing MEP amplitude and RMT before and after a 15-min period of SMS or sham stimulation over primary motor cortex (M1).

Conditioning the cortical silent period with paired transcranial magnetic stimulation.

Background: A single supra-threshold pulse of transcranial magnetic stimulation (TMS) over human motor cortex elicits multiple descending volleys (I-waves) that generate a motor evoked potential (MEP) followed by a period of electromyographic silence in the tonically contracted target muscle (silent period; SP). A sub-threshold conditioning stimulus (CS) delivered at inter-pulse intervals (IPIs) of 1-5 ms after a supra-threshold test stimulus (TS) conditions I-waves elicited by TS and can increase MEP amplitude (short-interval intracortical facilitation; SICF), however its effect on the SP remains unknown.

Objective: We investigated whether it is possible to modulate the SP resulting from a TS by delivering a sub-threshold CS 1-5 ms later.

Interaction between simultaneously applied neuromodulatory interventions in humans.

Background: Transcranial direct current stimulation (tDCS) is a neuromodulatory technique with the potential to enhance the efficacy of traditional therapies such as neuromuscular electrical stimulation (NMES). Yet, concurrent application of tDCS/NMES may also activate homeostatic mechanisms that block or reverse effects on corticomotor excitability. It is unknown how tDCS and NMES interact in the human primary motor cortex (M1) and whether effects are summative (increase corticomotor excitability beyond that of tDCS or NMES applied alone) or competitive (block or reduce corticomotor excitability effects of tDCS or NMES applied alone).

Interventional repetitive I-wave transcranial magnetic stimulation (TMS): the dimension of stimulation duration.

Background: A range of transcranial magnetic stimulation (TMS) techniques are now available to modulate human corticomotor excitability and plasticity. One presumably critical aspect of these interventions is their duration of application.

Objective: In the current study, we investigated whether doubling the duration of an intervention would offer any additional benefit, or invoke self-limiting mechanisms controlling corticomotor excitability or synaptic plasticity.

Reversal of TMS-induced motor twitch by training is associated with a reduction in excitability of the antagonist muscle.

Background: A single session of isolated repetitive movements of the thumb can alter the response to transcranial magnetic stimulation (TMS), such that the related muscle twitch measured post-training occurs in the trained direction. This response is attributed to transient excitability changes in primary motor cortex (M1) that form the early part of learning. We investigated; (1) whether this phenomenon might occur for movements at the wrist, and (2) how specific TMS activation patterns of opposing muscles underlie the practice-induced change in direction.

Spinal associative stimulation: a non-invasive stimulation paradigm to modulate spinal excitability.

Objective: Repetitive, paired peripheral and transcranial stimulation targeting the cerebral cortex can increase cortical excitability, outlasting the stimulation period. It is unknown whether paired stimulation specifically targeting the spinal cord can modulate spinal excitability. We tested whether the H-reflex facilitation from a sub-threshold conditioning TMS pulse could modulate spinal excitability if delivered repetitively.

A model of the contribution of late I-waves to α-motoneuronal activation: implications for paired-pulse TMS.

Background: In paired-pulse (conditioned-test) transcranial magnetic stimulation (TMS) protocols, the effect of the conditioning pulse on the test response can be substantial. Epidural recordings indicate that this is mediated through modulation of late indirect (I-) wave volleys. It is not well understood how strong effect sizes could arise from the later, and usually weaker, I-wave volleys.