Selective excitation of corticofugal neurones by surface‐anodal stimulation of the baboon's motor cortex

Hern, J. E. C.; Landgren, S.; Phillips, C. G.; Porter, R.

doi:10.1113/jphysiol.1962.sp006874

Cited by 203 publications

(117 citation statements)

References 14 publications

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“…The choice of a monopolar stimulus is based on investigations performed by Hern et al, 24 who examined the direct electrical excitability of pyramidal cells of the motor cortex and was the first author to advocate an anodic stimulation technique. In 1993 Taniguchi et al 53 described a further modification of the monopolar stimulation technique.…”

Section: Discussionmentioning

confidence: 99%

Subcortical mapping and monitoring during insular tumor surgery

Kombos

Süss²,

Vajkoczy³

2009

FOC

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Object The treatment of insular tumors is controversial. Surgical treatment is associated with a higher morbidity rate than other therapies. The present work presents a new method in which the descending motor pathways are monitored during surgery for insular tumors. Methods Intraoperative monitoring was performed in a combination of 2 techniques. The motor cortex was stimulated with a transcranial electrical stimulus. In addition, direct subcortical stimulation was performed with an electrical anodal monopolar stimulus. Compound motor action potentials (CMAPs) were recorded from target muscles. Results Fifteen patients were included in this preliminary study. Following transcranial stimulation, CMAPs were recorded in all cases. Subcortical stimulation was successful in 12 cases. Significant CMAP alterations were recorded in 5 patients. There were no false-negative results in the series. Conclusions The technique presented here is a safe method. It allows a quantitative monitoring of motor function and functional mapping of the pyramidal tract during insular surgery.

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Section: Discussionmentioning

confidence: 99%

Subcortical mapping and monitoring during insular tumor surgery

Kombos

Süss²,

Vajkoczy³

2009

FOC

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“…40, 90 Hern et al 51 demonstrated that anodic stimulation of the motor cortex leads to stimulation of the pyramidal cells. The anodic flow enters the dendrites, causes hyperpolarization, and exits the axon, where it produces depolarization (Fig.…”

Section: Neurophysiological Basismentioning

confidence: 99%

“…68 Experimental studies in animals have shown that anodic stimulation of the motor cortex produces a D-wave response, whereas cathodic stimulation elicits a pure Iwave response (without D wave). 51 Gorman 42 observed that a cathodic stimulus leads to a measurable latency prolongation of 100-150 µsec in the medulla oblongata.…”

Section: Neurophysiological Basismentioning

confidence: 99%

“…The choice of a monopolar stimulus is based on investigations performed by Hern,51 who examined the direct electrical excitability of pyramidal cells of the motor cortex and was the first author to propagate an anodic stimulation technique. These findings were confirmed by Gorman, 42 who compared various techniques for direct stimulation of the cortex.…”

Section: Monopolar Cortical Stimulationmentioning

confidence: 99%

“…75 Several studies have shown that an anode is more effective for MCS than a cathode 85,88 ; anodal current enters and hyperpolarizes dendrites, and leaves and depolarizes the axon or cell body. 88 Hern et al 51 have demonstrated a direct action of monopolar anodal stimulation on pyramidal cells. This is due to the fact that the axon and regions adjacent to the cell body have a much lower threshold than the dendrites and the cell body.…”

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confidence: 99%

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Neurophysiological basis of direct cortical stimulation and applied neuroanatomy of the motor cortex: a review

Kombos¹,

Süss²

2009

FOC

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Intraoperative electrical stimulation of the motor cortex is a sensitive method for intraoperative mapping and monitoring of this region. Two different stimulation techniques have been established, the bipolar and monopolar techniques. Controversy exists regarding the most suitable method. Both methods have advantages and disadvantages and different electrophysiological backgrounds. The present study is a review of the electrophysiological basis of direct cortical electrical stimulation of the motor cortex. Both methods are discussed and their field of application is presented.

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Corticomotoneuronal Organization

Phillips¹

1967

Arch Neurol

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which are the "common paths"1 of cortical integration, are the key to the organization of the motor cortex (Msl of Woolsey2). They form the output channel of a complex input-output system, whose input side, as yet, has received less investigation than the output (for a review of recent work, see reference 3). This paper is concerned with one only of the outputs: the corticospinal neurons projecting monosynaptically to motoneurons innervating the baboon's arm, forearm, and hand. These constitute the simplest and most direct of the known corticofugal pathways. In the cat, which has no monosynaptic corticospinal projection,4 there are corticospinal projections controlling the interneurons of reflex arcs5 and the neurons and presynaptic arborizations of ascending spinal pathways,6 and it would be surprising if comparable projections did not exist in the primates. A projection to fusimotor neurons has been found in monkeys by Mortimer and Akert.7 Finally, the corticofugal ax¬ ons from area Msl do not all pass through the medullary pyramid into the spinal cord. Corticorubral and other corticofugal neu¬ rons are intermingled with the corticospinal cells, and the characteristic somatotopic or¬ ganization of the baboon's area Msl is found, by electrical mapping, to survive cut¬ ting of the medullary pyramids.8 The cat has a somatotopically organized corticorubrospinal system9·10; again, it would be sur¬ prising if the primates had lost this, and the motor responses that survive pyramidal section may well depend on it.From this complex of projections from the motor area (Msl of Woolsey2) one can read-ily abstract the monosynaptic corticomotoneuronal system of Bernhard et al11 for ex¬ perimental analysis. Such an abstraction is not merely technically feasible, it is also physiologically significant. Since the ele¬ mentary neural basis of muscular control is the motor unit,12 the spatial organization of the corticospinal cells whose axons converge upon the membranes of single motoneurons is of the highest interest.Electrical mapping of the corticomotoneuronal system is difficult if one uses stimuli which are adequate, in virtue of strength, pulse duration, repetition frequency, or train duration, to evoke actual firing of spi¬ nal motoneurons. The difficulty arises from the fact that arbitrary manipulation of these parameters of stimulation allows one to draw different motor maps on the same brain.13 Lilly et al14 proposed that these maps are compounded, in different propor¬ tions, of direct electrical stimulation of corti¬ cofugal neurons and of stimulation of intracortical afferent systems which converge upon the corticofugal neurons and excite them synaptically. It is therefore necessary to choose a stimulus that will bypass the synaptic complexities of the intact cortex and will selectively excite the corticofugal neurons. One can then send single, small, well-synchronized pyramidal volleys from specific parts of area Msl into the spinal cord, and measure the quantity and timing of monosynaptic excitatory action upon mo...

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Selective excitation of corticofugal neurones by surface‐anodal stimulation of the baboon's motor cortex

Cited by 203 publications

References 14 publications

Subcortical mapping and monitoring during insular tumor surgery

Subcortical mapping and monitoring during insular tumor surgery

Neurophysiological basis of direct cortical stimulation and applied neuroanatomy of the motor cortex: a review

Corticomotoneuronal Organization

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