ABSTRACT
High-frequency oscillations (HFO) have been suggested to reflect the activity of thalamocortical and/or intracortical neurons bursting at high frequencies. These circuits seem to be involved in pathophysiological mechanisms of focal dystonia. In healthy subjects, we characterized the spectrotemporal properties of HFO patterns evoked by dominant-hand median-nerve stimulation, using magnetoencephalography coupled with time-frequency analysis. Then, we investigated HFO in patients with writer's cramp and found that HFO patterns are strongly decreased in power and disorganized in time. This supports the assumption that abnormal HFOs reflect pathophysiological mechanisms occurring in focal dystonia, possibly resulting from a dysfunction of somatosensory processing.
Subject(s)
Dystonic Disorders/physiopathology , Adult , Electric Stimulation/methods , Evoked Potentials, Somatosensory/physiology , Female , Functional Laterality/physiology , Humans , Magnetoencephalography/methods , Median Nerve/physiopathology , Middle Aged , Reaction Time , Time FactorsABSTRACT
Intracranial electroencephalography was recorded in an epileptic patient when he was listening to dissonant and consonant chords and to minor and major chords. Changes in dissonance induced event-related potentials (ERPs) in the auditory areas from 200 ms onward, in the orbito-frontal cortex (500-1000 ms), and later in the amygdala and anterior cingulate gyrus (1200-1400 ms), suggesting the sequential involvement of these brain structures in implicit emotional judgment of musical dissonance. Changes in musical mode induced ERPs only in the orbito-frontal cortex (500-1000 ms), emphasizing the implication of this frontal region in emotional judgment of pleasant music.