Organization of Ipsilateral Excitatory and Inhibitory Pathways in the Human Motor Cortex

2003 ◽  
Vol 89 (3) ◽  
pp. 1256-1264 ◽  
Author(s):  
Robert Chen ◽  
Derek Yung ◽  
Jie-Yuan Li
Keyword(s):  
Motor Cortex ◽  
Induced Current ◽  
Motor Cortex Stimulation ◽  
Inhibitory Effects ◽  
Conditioning Stimulation ◽  
Human Motor Cortex ◽  
Voluntary Muscle ◽  
Directional Preference ◽  
The Right ◽  
Stimulation Of

Motor cortex stimulation has both excitatory and inhibitory effects on ipsilateral muscles. Excitatory effects can be assessed by ipsilateral motor-evoked potentials (iMEPs). Inhibitory effects include an interruption of ipsilateral voluntary muscle activity known as the silent period (iSP) and a reduction in corticospinal excitability evoked by conditioning stimulation of the contralateral motor cortex (interhemispheric inhibition, IHI). Both iSP and IHI may be mediated by transcallosal pathways. Their relationship to the contralateral corticospinal projection and whether iSP and IHI represent the same phenomenon remain unclear. The neuronal population activated by transcranial magnetic stimulation (TMS) is highly dependent on the direction of the induced current in the brain. We examined the relationship among iMEP, iSP, IHI, and the contralateral corticospinal system by examining the effects of different stimulus intensities and current directions. Surface electromyography (EMG) was recorded from both first dorsal interosseous (FDI) muscles. The iSP in the right FDI muscle was obtained by right motor cortex stimulation during voluntary muscle contraction. IHI was examined by conditioning stimulation of the right motor cortex followed by test stimulation of the left motor cortex at interstimulus intervals (ISIs) of 2–80 ms. The induced current directions tested in the right motor cortex were anterior medial (AM), posterior medial (PM), posterior lateral, and anterior lateral (AL). Contralateral MEPs (cMEPs) had the lowest threshold with the AM direction and the shortest latency with the PM direction. iMEPs were present in 8 of 10 subjects. Both iMEP and IHI did not show significant directional preference. iSP was observed in all subjects with the highest threshold for the AL direction and the longest duration for the AM direction. cMEP, iSP, and IHI all increased with stimulus intensity up to ∼75% stimulator output. Target muscle activation decreased IHI at 8-ms ISI but had little effect on IHI at 40-ms ISI. iSP and IHI at 8-ms ISI did not correlate at any stimulus intensities and current directions tested, and factor analysis showed that they are explained by different factors. However, active IHI at 40-ms ISI was explained by the same factor as iSP. The different directional preference for cMEP compared with iMEP and IHI suggests that these ipsilateral effects are mediated by populations of cortical neurons that are different from those activating the corticospinal neurons. iSP and IHI do not represent the same phenomenon and should be considered complementary measures of ipsilateral inhibition.

Magnetic stimulation of the human motor cortex evokes skin sympathetic nerve activity

2000 ◽  
Vol 88 (1) ◽  
pp. 126-134 ◽  
Author(s):  
David H. Silber ◽  
Lawrence I. Sinoway ◽  
Urs A. Leuenberger ◽  
Vahe E. Amassian
Keyword(s):  
Motor Cortex ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Cortical Stimulation ◽  
Motor Cortex Stimulation ◽  
Nerve Activity ◽  
Human Motor Cortex ◽  
Skin Sympathetic Nerve Activity ◽  
Motor Cortical ◽  
Stimulation Of

Single-pulse magnetic coil stimulation (Cadwell MES 10) over the cranium induces without pain an electric pulse in the underlying cerebral cortex. Stimulation over the motor cortex can elicit a muscle twitch. In 10 subjects, we tested whether motor cortical stimulation could also elicit skin sympathetic nerve activity (SSNA; n = 8) and muscle sympathetic nerve activity (MSNA; n = 5) in the peroneal nerve. Focal motor cortical stimulation predictably elicited bursts of SSNA but not MSNA; with successive stimuli, the SSNA responses did not readily extinguish (94% of discharges to the motor cortex evoked SSNA responses) and had predictable latencies [739 ± 33 (SE) to 895 ± 13 ms]. The SSNA responses were similar after stimulation of dominant and nondominant sides. Focal stimulation posterior to the motor cortex elicited extinguishable SSNA responses. In three of six subjects, anterior cortical stimulation evoked SSNA responses similar to those seen with motor cortex stimulation but without detectable movement; in the other subjects, anterior stimulation evoked less SSNA discharge than that seen with motor cortex stimulation. Contrasting with motor cortical stimulation, evoked SSNA responses were more readily extinguished with 1) peripheral stimulation that directly elicited forearm muscle activation accompanied by electromyograms similar to those with motor cortical stimulation; 2) auditory stimulation by the click of the energized coil when off the head; and 3) in preliminary experiments, finger afferent stimulation sufficient to cause tingling. Our findings are consistent with the hypothesis that motor cortex stimulation can cause activation of both α-motoneurons and SSNA.

scholarly journals Pre-motor versus motor cerebral cortex neuromodulation for chronic neuropathic pain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Igor Lavrov ◽  
Timur Latypov ◽  
Elvira Mukhametova ◽  
Brian Lundstrom ◽  
Paola Sandroni ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Cerebral Cortex ◽  
Motor Cortex ◽  
Initial Assessment ◽  
Motor Cortex Stimulation ◽  
Chronic Neuropathic Pain ◽  
Long Term Effect ◽  
Stimulation Of

AbstractElectrical stimulation of the cerebral cortex (ESCC) has been used to treat intractable neuropathic pain for nearly two decades, however, no standardized approach for this technique has been developed. In order to optimize targeting and validate the effect of ESCC before placing the permanent grid, we introduced initial assessment with trial stimulation, using a temporary grid of subdural electrodes. In this retrospective study we evaluate the role of electrode location on cerebral cortex in control of neuropathic pain and the role of trial stimulation in target-optimization for ESCC. Location of the temporary grid electrodes and location of permanent electrodes were evaluated in correlation with the long-term efficacy of ESCC. The results of this study demonstrate that the long-term effect of subdural pre-motor cortex stimulation is at least the same or higher compare to effect of subdural motor or combined pre-motor and motor cortex stimulation. These results also demonstrate that the initial trial stimulation helps to optimize permanent electrode positions in relation to the optimal functional target that is critical in cases when brain shift is expected. Proposed methodology and novel results open a new direction for development of neuromodulation techniques to control chronic neuropathic pain.

THO10 Changes in intracortical circuits of the human motor cortex following theta burst stimulation of the lateral cerebellum

2008 ◽  
Vol 119 ◽  
pp. S29-S30 ◽  
Author(s):  
Giacomo Koch ◽  
John Rothwell ◽  
Francesco Mori ◽  
Barbara MArconi ◽  
Massimiliano Oliveri ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Human Motor Cortex ◽  
Intracortical Circuits ◽  
Human Motor ◽  
Theta Burst ◽  
Stimulation Of

scholarly journals Transcranial static magnetic field stimulation of the human motor cortex

2011 ◽  
Vol 589 (20) ◽  
pp. 4949-4958 ◽  
Author(s):  
Antonio Oliviero ◽  
Laura Mordillo-Mateos ◽  
Pablo Arias ◽  
Ivan Panyavin ◽  
Guglielmo Foffani ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Motor Cortex ◽  
Static Magnetic Field ◽  
Field Stimulation ◽  
Human Motor Cortex ◽  
Human Motor ◽  
Stimulation Of

P025 Minocycline has acute inhibitory effects on human motor cortex excitability

2008 ◽  
Vol 119 ◽  
pp. S77
Author(s):  
Nicolas Lang ◽  
Daniella Terney ◽  
Holger Rothkegel ◽  
Andrea Antal ◽  
Walter Paulus
Keyword(s):  
Motor Cortex ◽  
Inhibitory Effects ◽  
Human Motor Cortex ◽  
Motor Cortex Excitability ◽  
Human Motor

Parabrachial area and nucleus raphe magnus-induced modulation of nociceptive and nonnociceptive trigeminal subnucleus caudalis neurons activated by cutaneous or deep inputs

1994 ◽  
Vol 71 (6) ◽  
pp. 2430-2445 ◽  
Author(s):  
C. Y. Chiang ◽  
J. W. Hu ◽  
B. J. Sessle
Keyword(s):  
Spontaneous Activity ◽  
Inhibitory Effects ◽  
Conditioning Stimulation ◽  
Nucleus Raphe Magnus ◽  
Nociceptive Neurons ◽  
Nociceptive Responses ◽  
Significant Difference ◽  
Raphe Magnus ◽  
Trigeminal Subnucleus Caudalis ◽  
Stimulation Of

1. The aim of this study was to test whether parabrachial area (PBA) stimulation exerts inhibitory influences on the spontaneous activity and responses evoked by skin and deep afferent inputs in trigeminal subnucleus caudalis (Vc) neurons, and to compare these effects with those of nucleus raphe magnus (NRM) stimulation. A total of 92 nonnociceptive and nociceptive Vc neurons was recorded in urethan/alpha-chloralose-anesthetized rats. Each neuron was functionally classified as low-threshold mechanoceptive (LTM), wide dynamic range (WDR), nociceptive-specific (NS), nociceptive convergent with both skin and deep inputs (S+D), or deep nociceptive (D); the LTM neurons could be subdivided as rapidly adapting (RA) or slowly adapting (SA). Conditioning stimulation was applied to histologically verified sites in PBA and NRM. 2. The spontaneous or evoked activity of all classes of neurons could be inhibited by PBA as well as by NRM stimulation, but generally the incidence and magnitude of inhibition were lower for the LTM neurons. Occasionally, facilitation of neuronal activity was also produced by PBA and NRM stimulation. 3. The spontaneous activity of 11 LTM neurons (6 RA, 5 SA), 13 nociceptive neurons (6 WDR, 7 NS), and 5 D neurons was tested with stimulation of PBA or NRM or both. LTM spontaneous activity was more significantly inhibited by NRM stimulation than by PBA stimulation, whereas both NRM and PBA stimulation had similar and significant inhibitory effects on NS, WDR, and D neurons. 4. The evoked nonnociceptive responses of 28 LTM neurons (16 RA, 12 SA) and of 6 WDR neurons were also tested with stimulation of PBA or NRM or both. The magnitudes of inhibition of the responses produced by PBA conditioning stimulation were statistically significantly less than those induced by NRM conditioning stimulation. 5. The cutaneous and deep nociceptive responses of cutaneous nociceptive neurons (9 NS, 19 WDR) and seven D neurons, respectively, were also tested with PBA and NRM stimulation. There was a significant difference in potency between PBA- and NRM-induced inhibition, but no difference in the magnitude of inhibitory effects among NS, WDR, and D neurons. For both PBA and NRM conditioning stimulation, graded increases in intensities of stimulation produced linear increases in inhibitory effects on nociceptive responses; an increase in stimulation frequency from 5 to 400 Hz also produced increases in inhibition of the nociceptive responses. 6. In five S+D nociceptive convergent neurons, the responses elicited by deep inputs were more powerfully inhibited by PBA stimulation than those elicited by cutaneous inputs.(ABSTRACT TRUNCATED AT 400 WORDS)

NON-INVASIVE MAGNETIC STIMULATION OF HUMAN MOTOR CORTEX

The Lancet ◽  
1985 ◽  
Vol 325 (8437) ◽  
pp. 1106-1107 ◽  
Author(s):  
A.T. Barker ◽  
R. Jalinous ◽  
I.L. Freeston
Keyword(s):  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Human Motor Cortex ◽  
Non Invasive ◽  
Human Motor ◽  
Stimulation Of
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