No abstract available.
Motor Cortex*

No abstract available.
Motor Cortex*

OBJECTIVE: To evaluate motor excitability and hand function on the non-dominant side according to the polarity of transcranial direct current stimulation (tDCS) on the motor cortex in a healthy person. METHOD: tDCS was applied to the hand motor cortex for 15 minutes at an intensity of 1 mA in 28 healthy right-handed adults. Subjects were divided randomly into four groups: an anodal tDCS of the non-dominant hemisphere group, a cathodal tDCS of the non-dominant hemisphere group, an anodal tDCS of the dominant hemisphere group, and a sham group. We measured the motor evoked potential (MEP) in the abductor pollicis brevis and Jabsen-Taylor hand function test (JTT) in the non-dominant hand prior to and following tDCS. All study procedures were done under double-blind design. RESULTS: There was a significant increase in the MEP amplitude and a significant improvement in the JTT in the non-dominant hand following anodal tDCS of the non-dominant hemisphere (p<0.05). But there was no change in JTT and a significant decrease in the MEP amplitude in the non-dominant hand following cathodal tDCS on the non-dominant hemisphere and anodal tDCS of the dominant hemisphere. CONCLUSION: Non-dominant hand function is improved by increased excitability of the motor cortex. Although motor cortex excitability is decreased in a healthy person, non-dominant hand function is maintained. A homeostatic mechanism in the brain might therefore be involved in preserving this function. Further studies are warranted to examine brain functions to clarify this mechanism.
Adult ; Brain ; Evoked Potentials, Motor ; Hand ; Humans ; Motor Cortex ; Salicylamides

OBJECTIVE: To study the after effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex on cortical excitability METHOD: Twenty healthy volunteers received 1,000 stimuli of 10 Hz rTMS. Repetitive TMS was given over the 'motor hot spot' of the right first dorsal interosseus muscle using an intensity of 80% of resting motor threshold. We evaluated the amplitude of motor evoked potential (MEP) using single pulse TMS and intracortical inhibition and intracortical facilitation with paired pulse TMS paradigm. After baseline measurement, the amplitude was measured immediately after stimulation and 10, 20, 30 and 40 minutes after rTMS. RESULTS: The amplitude of MEP was significantly increased for 10 minutes after applying 1,000 stimuli of 10 Hz rTMS. Additionally, intracortical inhibition was significantly reduced and intracortical facilitation was significantly enhanced for 10 minutes after 10 Hz rTMS. CONCLUSION: These results showed that 1,000 stimuli of 10 Hz rTMS over primary motor cortex increased the corticospinal excitability for 10 minutes. In addition, 10 Hz rTMS induced a suppression of the intracortical inhibitory circuitry and facilitation of the excitatory circuity for 10 minutes.
Evoked Potentials, Motor ; Healthy Volunteers ; Motor Cortex ; Transcranial Magnetic Stimulation*

OBJECTIVE: This explored whether the effects of Repetitive Transcranial Magnetic Stimulation (rTMS) on corticospinal excitability are dependent on the stimulation frequency. METHOD: Ten subjects were investigated using either 20 Hz or 1 Hz rTMS. To reduce inter-individual variability, we explored same subject in one week interval with different frequency. TMS was conducted with intensity of 90% of motor threshold. The effect of rTMS with EMG amplitude evoked in First Dorsal Interossei by TMS. Test motor evoked potentials were evaluated with intensity of 110% of motor threshold before rTMS, during the interval and immediately, 5 minutes, 20 minutes after the end of train. RESULTS: The analysis showed a significant decrease of cortical excitability after 1 Hz rTMS and an increase after 20 Hz rTMS. In low-frequency, Motor Evoked Potential (MEP) amplitude decreased quickly after initial 300 pulses stimulation. In high-frequency, there were some variation of individual MEP in the response to rTMS. The changes of MEP amplitude after 1200 stimulation continued until 20 minutes. CONCLUSION: These results provided basic evidence of rTMS for modulation of cortical excitability and could be further applied in patients group.
Evoked Potentials, Motor ; Humans ; Motor Cortex ; Transcranial Magnetic Stimulation*

OBJECTIVE: To compare the effect of electroacupuncture (EA), motor training (MT) and EA combined with MT on motor learning and motor cortex excitability in healthy subjects, and to explore the effect of EA combined with MT on synaptic metaplasticity. METHODS: Using self-control design, 12 healthy subjects were assigned into an EA group, a motor training group (MT group) and an EA plus motor training group (EA+MT group) successively, wash-out period of at least 2 weeks was required between each group. EA was applied at left Hegu (LI 4) in the EA group for 30 min, with continuous wave, 2 Hz in frequency and 0.5-1 mA in density. Motor training of left hand was adopted in the MT group for 30 min. EA and motor training were adopted in the EA+MT group successively. The time of finishing grooved pegboard test (GPT) was observed, and the average amplitude of motor evoked potentials (MEPs), the rest motor threshold (rMT) and the latency were recorded by transcranial magnetic stimulation technique before intervention (T0), after intervention (T1) and 30 min after EA (T3) in the EA group and the EA+MT group, T0 and T1 in the MT group. RESULTS: Compared with T0, the time of finishing GPT was shortened at T1 in the MT group and at T2 in the EA group and the EA+MT group ( CONCLUSION In physiological state, electroacupuncture combined with motor training have a synergistic effect on motor learning, while have no such effect on excitability of cerebral motor cortex.
Electroacupuncture ; Evoked Potentials, Motor ; Hand ; Humans ; Motor Cortex

PURPOSE: To demonstrate activation signals within the cerebellar cortex and to determine the side of thecerebellar cortex eliciting activation signals in response to complex motor tasks, as seen on EPI fMRI MATERIALS AND METHODS: Seven right-handed subjects (M:F=3:4;mean age, 30.3 years) underwent repetitive finger appositionwith the dominant right hand. Using a 1.5T MRI scanner, EPI fMR images were obtained. MR parameters used for EPIfMRI were TR/TE/Flip angle : 0.96 msec/64 msec/90 degree, FOV 22cm, 128 X 128 matrix, 10 slices, 10mm thickness whilethose for SE T1 weighted localized images were TR/TE : 450/16, FOV 23cm, 256 X 256 matrix. The paradigm was threesets of alternate resting and moving fingers for six cycles, resulting in times of 360 seconds (10 slices X 15 EPIX 6 cycles = 900 images). Image processing involoved the use of a 200mHz Dual Pentium PC with homemade software.T-testing (p<0.005) and time series analysis were performed, and to verify the locations of activated regions,resulting images were analyzed in a color-coded overlay to reference T1-weighted spin echo coronal images.percentage change in signal intensity (PCSI) was calculated from the processed data. RESULTS: All normal subjectsshowed significant activation signals in both the contralateral (left) primary motor cortex (PCSI=3.12%+/-0.96) andipsilateral (right) cerebellar cortex (PCSI=3.09%+/-1.14). Signal activation was detected in the contralateralsupplemental motor area (2.91%+/-0.82), and motor activation in the anterior upper half of the contralateralcerebellum (PCSI=2.91%+/-0.69). The difference in activation signals between both sides of the cerebellar cortexwas not statistically significant. All data were matched with time-series analysis. CONCLUSION: Bilateralcerebellar activation is associated with unilateral complex finger movements, as seen on fMRI. This result maysupport the recent neurological observation that the cerebellum may exert bilateral effects on motor performance.
Cerebellar Cortex ; Cerebellum* ; Fingers ; Hand ; Magnetic Resonance Imaging* ; Motor Cortex

Small cortical strokes can produce predominant isolated weakness in a particular group of fingers: radial or ulnar. The traditional views are of point-to-point representations of each finger to neurons located in the precentral gyrus of the motor cortex such that the neurons of the radial fingers are located laterally and those of the ulnar fingers are located medially. We present a case of isolated weakness of middle, ring, and little fingers due to a small cortical infarction in the medial precentral gyrus.
Fingers* ; Infarction* ; Motor Cortex ; Neurons ; Stroke

OBJECTIVE: To evaluate the effect of hyperbaric air therapy (HAT) on activity of cerebral motor cortex METHOD: Eighteen right-handed subjects were recruited, who had no brain lesion and did not take any medication that can affect brain function. Experimental group (n=9) underwent motor evoked potential (MEP) study by transcranial magnetic stimulation before and after 1-hour HAT. Control group (n=9) also received motor evoked potential study twice with 1 hour interval. The cortical activity was evaluated with parameters such as resting motor threshold (rMT), amplitude of MEP, intracortical inhibition (ICI) and intracortical facilitation (ICF) and recruitment curve (RC). RESULTS: There was no significant difference of rMT, MEP, ICI, ICF and RC between experimental group and control group. CONCLUSION: One -hour hyperbaric air therapy could not modulate any cortical motor activity in health human brain.
Brain ; Evoked Potentials, Motor ; Humans* ; Motor Activity ; Motor Cortex* ; Transcranial Magnetic Stimulation

OBJECTIVE: To study the changes of magnetic evoked potentials by thinking of simple motion without actual muscle action of that motion. METHOD: We use H-reflex to test the excitability of relevant pools of spinal motor neurons and Magnetic Evoked Potentials (MEPs) to study the core of brain motor activity. The H-reflex and MEPs were obtained in three different conditions. 1) non-facilitation (NF), that is, resting state without actual motion and without thinking of that motion. 2) volitional-faciliation (VF), with actual motion which is usual manner of facilitation of MEPs. 3) thinking-facilitation (TF), without actual motion but with imaginary thinking of that motion. We evaluate the thresholds, amplitudes and latencies of H-reflex and MEPs in each three condition. RESULTS: Comparing with the parameters in NF condition as a baseline, there were no significant changes in any parameters of H-reflex in TF condition, but there were significant changes in threshold and amplitude of H-reflex in VF. On the while there were significant changes both in VF and TF of MEPs. The amount of facilitation of MEPs were greater in VF than in TF; the amount threshold decrement, amplitude increment and latency decrement of MEPs were greater in VF than in TF. CONCLUSION: Thinking of simple motion without actual muscle action of that motion could facilitate the MEPs, and this facilitation is induced by increasing activity of brain motor cortex not by that of spinal cord level.
Brain ; Evoked Potentials* ; H-Reflex ; Motor Activity ; Motor Cortex ; Motor Neurons ; Spinal Cord ; Thinking*