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1. In seven normal subjects, subthreshold transcranial magnetic conditioning stimuli (using a figure-of-eight coil) were applied over the motor cortex in order to evoke activity in intracortical neuronal circuits. The net effect on cortical excitability was evaluated by measuring the effect on the size of EMG responses elicited in the abductor digiti minimi(More)
The effect of a single oral dose of various antiepileptic drugs on the excitability of the motor system was studied in healthy volunteers by means of transcranial magnetic stimulation. Motor threshold, duration of the cortical silent period, and intracortical excitability after double-shock transcranial stimulation were tested before and at defined(More)
1. Transcranial magnetic stimulation (TMS) of the human motor cortex results in multiple discharges (D and I waves) in the corticospinal tract. We tested whether these volleys can be explored non-invasively with paired TMS. The intensity of the first stimulus (S1) was set to produce a motor-evoked potential (MEP) of 1 mV in the resting contralateral(More)
The effect of the short-acting benzodiazepine lorazepam on motor cortex excitability was investigated in 11 healthy volunteers using the technique of focal transcranial magnetic stimulation. The threshold intensity for evoking an electromyographic response in the resting and active abductor digiti minimi muscle, the size of the motor evoked potential, the(More)
Learning may alter rapidly the output organization of adult motor cortex. It is a long-held hypothesis that modification of synaptic strength along cortical horizontal connections through long-term potentiation (LTP) and long-term depression (LTD) forms one important mechanism for learning-induced cortical plasticity. Strong evidence in favor of this(More)
The corpus callosum (CC) is the principal white matter fiber bundle connecting neocortical areas of the two hemispheres. Although an object of extensive research, important details about the anatomical and functional organization of the human CC are still largely unknown. Here we focused on the callosal motor fibers (CMFs) that connect the primary motor(More)
Behavioural studies indicate that a newly acquired motor skill is rapidly consolidated from an initially unstable state to a more stable state, whereas neuroimaging studies demonstrate that the brain engages new regions for performance of the task as a result of this consolidation. However, it is not known where a new skill is retained and processed before(More)
Deafferentation leads to cortical reorganization that may be functionally beneficial or maladaptive. Therefore, we were interested in learning whether it is possible to purposely modulate deafferentation-induced reorganization. Transient forearm deafferentation was induced by ischemic nerve block (INB) in healthy volunteers. The following five interventions(More)
  • Ulf Ziemann
  • Clinical neurophysiology : official journal of…
  • 2004
The application of a single dose of a CNS active drug with a well-defined mode of action on a neurotransmitter or neuromodulator system may be used for testing pharmaco-physiological properties of transcranial magnetic stimulation (TMS) measures of cortical excitability. Conversely, a physiologically well-defined single TMS measure of cortical excitability(More)
Paired transcranial magnetic stimulation has greatly advanced our understanding of the mechanisms which control excitability in human motor cortex. While it is clear that paired-pulse excitability depends on the exact interstimulus interval (ISI) between the first (S1) and second stimulus (S2), relatively little is known about the effects of the intensities(More)