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Cortical Origin (cortical + origin)

Distribution by Scientific Domains
Medical Sciences75%

Selected Abstracts

Elemental mercury poisoning probably causes cortical myoclonus

MOVEMENT DISORDERS, Issue 13 2007
Mona Ragothaman MBBS
Abstract Mercury toxicity causes postural tremors, commonly referred to as "mercurial tremors," and cerebellar dysfunction. A 23-year woman, 2 years after injecting herself with elemental mercury developed disabling generalized myoclonus and ataxia. Electrophysiological studies confirmed the myoclonus was probably of cortical origin. Her deficits progressed over 2 years and improved after subcutaneous mercury deposits at the injection site were surgically cleared. Myoclonus of cortical origin has never been described in mercury poisoning. It is important to ask patients presenting with jerks about exposure to elemental mercury even if they have a progressive illness, as it is a potentially reversible condition as in our patient. © 2007 Movement Disorder Society [source]

Rhythmic cortical myoclonus in Niemann,Pick disease type C

MOVEMENT DISORDERS, Issue 9 2006
Laura Canafoglia MD
Abstract We here describe a patient with late-infantile Niemann,Pick disease type C (NPC) presenting with worsening myoclonus, seizures, cerebellar symptoms, mild mental impairment, and gaze palsy. Electroencephalographic (EEG) ,polymyographic examinations showed abnormally high and diffuse background alpha-activity, enhanced by intermittent photic stimulation. The electromyographic (EMG) showed quasirhythmic myoclonic jerks during motor activation. EEG,EMG frequency analysis (better than jerk-locked back-averaging) demonstrated the cortical origin of the myoclonus. Our observations indicate that cortical myoclonus may occur as the main symptom of NPC. © 2006 Movement Disorder Society [source]

Low-frequency repetitive transcranial magnetic stimulation suppresses specific excitatory circuits in the human motor cortex

THE JOURNAL OF PHYSIOLOGY, Issue 18 2008
V. Di Lazzaro
Previous studies have shown that low-frequency repetitive transcranial magnetic stimulation (rTMS) suppresses motor-evoked potentials (MEPs) evoked by single pulse TMS. The aim of the present paper was to investigate the central nervous system level at which rTMS produces a suppression of MEP amplitude. We recorded corticospinal volleys evoked by single pulse TMS of the motor cortex before and after 1 Hz rTMS in five conscious subjects who had an electrode implanted in the cervical epidural space for the control of pain. One of the patients had Parkinson's disease and was studied on medication. Repetitive TMS significantly suppressed the amplitude of later I-waves, and reduced the amplitude of concomitantly recorded MEPs. The earliest I-wave was not significantly modified by rTMS. The present results show that 1 Hz rTMS may decrease the amplitude of later descending waves, consistent with a cortical origin of the effect of 1 Hz rTMS on MEPs. [source]

Developmental plasticity connects visual cortex to motoneurons after stroke

ANNALS OF NEUROLOGY, Issue 1 2010
Anna Basu BM
We report motor cortical function in the left occipital cortex of a subject who suffered a left middle cerebral artery stroke early in development. Transcranial magnetic stimulation of the left occipital cortex evoked contraction of right hand muscles. Electroencephalogram recorded over the left occipital cortex showed: 1) coherence with electromyogram from a right hand muscle; 2) a typical sensorimotor Mu rhythm at rest that was suppressed during contraction of right hand muscles. This is the first evidence that cortical plasticity extends beyond reshaping of primary sensory cortical fields to respecification of the cortical origin of subcortically projecting pathways. ANN NEUROL 2010;67:132,136 [source]