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Magnetic coil (MC) stimulation percutaneously of human occipital cortex was tested on perception of 3 briefly presented, randomly generated alphabetical characters. When the visual stimulus-MC pulse interval was less than 40-60 msec, or more than 120-140 msec, letters were correctly reported; at test intervals of 80-100 msec, a blur or nothing was seen.(More)
Pairs of threshold magnetic stimuli were applied over the motor cortex at interstimulus intervals of 1-6 ms, and EMG responses recorded from the relaxed or active first dorsal interosseous muscle of 7 normal subjects. In relaxed subjects, when the interval between the stimuli was around 1.0-1.5 ms, 2.5-3.0 ms or 4.5 ms or later, the size of the response to(More)
This contribution includes a selective review of previously published material, findings from some new experiments, and discussion of some relationships between animal and recent human data. The major questions are: What descends from the cerebral cortex after a brief surface stimulus? What explains the various components of the corticofugal discharge? What(More)
The effects of different orientations of a Cadwell round magnetic coil (MC) were compared with each other and with surface electrical stimulation of motor cortex in monkeys anesthetized with pentobarbital or urethane. Recordings were made from within the lateral corticospinal tract, either from axonal populations or with a microelectrode from individual(More)
Human transcallosal responses (TCRs) were elicited by focal magnetic coil (MC) stimulation of homologous sites in contralateral frontal cortex and compared with those to focal anodic stimulation. With MC stimulation, the TCR consisted of an initially positive wave with an onset latency of 8.8-12.2 msec, a duration of 7-15 msec, and an amplitude which(More)
Focal stimulation over human cerebellum with a figure 8 magnetic coil (MC) results in an evoked wave recorded from bipolar scalp electrodes on the interaural line and more anteriorly. In 3 subjects, the wave responses along the interaural line had latencies of 8.8-13.8 msec, lasted 17.4-29.0 msec and had a maximum amplitude of 14.4-26.8 microV. The(More)
BACKGROUND The objective of this study was to determine whether differentiation between demyelinating and axonal neuropathies could be enhanced by comparing conduction time changes in defined segments of the total peripheral nerve pathway. METHODS Compound muscle action potentials (CMAPs) were elicited by cathodal stimulation of the tibial nerve at the(More)
Using principles derived from electric field measurements and studies of phrenic nerve in vitro, neuromagnetic stimuli in humans were predicted to excite selective low threshold sites in proximal and distal cauda equina. Physical models, in which induced electric fields were recorded in a segment of human lumbosacral spine immersed in a saline filled tank,(More)
The amplitudes of motor evoked potentials to transcranial magnetic stimulation from muscles immediately proximal to a temporarily anaesthetized (Bier's block) human forearm increase in minutes after the onset of anaesthesia and return to control values after the anaesthesia subsides. In order to determine the level at which the early modulation of human(More)
To help elucidate some basic principles of magnetic coil (MC) excitation of cerebral cortex, a model system was devised in which mammalian phrenic nerve, or amphibian sciatic nerve with its branches was suspended in appropriate Ringer's solution in a human brain-shaped volume conductor, an inverted plastic skull. The nerve was recorded monophasically out of(More)