Electric vs magnetic trans-cranial stimulation of the brain in healthy humans: a comparative study of central motor tracts ‘conductivity’ and ‘excitability’

Corticospinal output and cortical excitation‐inhibition balance in distal hand muscle representations in nonprimary motor area

“…Suprathreshold stimuli elicit larger MEPs with shorter latencies and longer duration than weaker stimuli [Caramia et al, 1989]. We may speculate that the stimulation of OP representation in M1 with the same absolute intensity as representation in NPMA would evoke MEPs with equal latencies when compared to stimulations of NPMA as was observed in our previous study .…”

Motor evoked potentials (MEP) and evoked pressure curves (EPC) from the urethral compressive musculature (UCM) by functional magnetic stimulation in healthy volunteers and patients with neurogenic incontinence

“…The threshold energy of 80^100% of maximal output to evoke a tc MEP response is clearly higher than that necessary to provoke muscles of the extremities; it is presumed, that this is caused by the deeper anatomical position of the representative EUS areal within the interhemispheric gap of the motor cortex and that the magnetic ¢eld is reduced there in comparison to the more super¢cial positioned areas of arms and legs [Hess et al, 1986;Caramia et al, 1989;Opsomer et al, 1989b;Dvorak et al, 1991;Eisen, 1992].…”

“…Normal values of peripheral (ls) and central spinal (tc) MEP latencies of the pelvic £oor (i.e., external anal sphincter and bulbocavernous muscles) have been evaluated by needle or surface electrodes [Opsomer et al, 1989a,b;Tabaraud et al, 1989a;Dressler et al, 1990;Ertekin et al, 1990;Ghezzi et al, 1991;Herdmann et al, 1991Herdmann et al, , 1995Osterhage et al, 1993;Loening-Baucke et al, 1994;Pelliccioni et al, 1997;Sato et al, 2000]. The advantage of using magnetic instead of electrical stimulation and of surface electrodes instead of needles is due to its painless, non-invasive application [Caramia et al, 1989;Dvorak et al, 1991;Pelliccioni et al, 1997]. Only a few studies investigated central spinal and peripheral nervous conduction time to the striated external urethral sphincter (EUS) in healthy subjects [Snooks and Swash, 1984a,b;Vodusek and Zidar, 1988;Thiry and Deltenre, 1989;Eardley et al, 1990Eardley et al, , 1991Mathers et al, 1990;Brostrom et al, 2003a,b], neurogenic urinary incontinence [Snooks and Swash, 1984b;Eardley et al, 1990Eardley et al, , 1991Mathers et al, 1990;Brodak et al, 1993] and fecal incontinence [Ki¡ and Swash, 1984a,b;Swash and Snooks, 1986;Jameson et al, 1994;Jost, 1997].…”

“…By application of electrical or magnetic stimuli to the motor cortex or to peripheral nerves electrophysiological activity of the target muscle can be elicited and the amplitude and latency of these evoked potentials can be measured [Caramia et al, 1989;Dvorak et al, 1992]. Normal values of peripheral (ls) and central spinal (tc) MEP latencies of the pelvic £oor (i.e., external anal sphincter and bulbocavernous muscles) have been evaluated by needle or surface electrodes [Opsomer et al, 1989a,b;Tabaraud et al, 1989a;Dressler et al, 1990;Ertekin et al, 1990;Ghezzi et al, 1991;Herdmann et al, 1991Herdmann et al, , 1995Osterhage et al, 1993;Loening-Baucke et al, 1994;Pelliccioni et al, 1997;Sato et al, 2000].…”

Interhemispheric differences of hand muscle representation in human motor cortex

“…A tightly adherent and transparent plastic cap was put ria. 4,28 Briefly, TCS intensity was progressively incremented until it reached a level providing reliable on the subject's head and modeled over the scalp. Anatomical landmarks (nasion-inion line or sagittal MEPs of у50 V in about 50% of a cascade of 10-20 consecutive stimuli.…”