Biomaterial Database

The pathophysiology and pharmacology of photic cortical reflex myoclonus. 1993

J Artieda, and J A Obeso

Department of Neurology, Clinica Universitaria, University of Navarra Medical School, Pamplona, Spain.

We studied 6 patients with myoclonus elicited by flash stimulation (1-15 Hz). Multichannel electromyographic recording showed a rostrocaudal recruitment order for the generalized myoclonic jerk. In all patients, each flash induced a large (36.9 +/- 5.7 microV) frontal biphasic wave with an onset latency of 42 msec that preceded the earliest muscle response in the face by at least 4 msec (range, 4-7 msec), the activity in the biceps by 11 to 14 msec, and the activity in tibialis anterior by 26 to 34 msec. Occipital potentials evoked by the same flash stimulation had a latency of 33.7 msec and were of normal amplitude (2.1 +/- 1.2 microV). Brain-mapping analysis indicated that the frontal activity correlated with the myoclonus originated in the premotor and motor cortices. These findings provide evidence for a cortical origin of this form of stimulus-sensitive myoclonus in humans. Administration of apomorphine and lisuride (intravenously) and levodopa-carbidopa (orally) abolished the photic myoclonus. Intravenous 5-hydroxytryptophan plus carbidopa (orally) and piracetam (orally) were also effective against photic myoclonus. The wide range of drugs active against photic cortical myoclonus suggests the participation of several biochemical mechanisms in its origin.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009207	Myoclonus	Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASES; (e.g., EPILEPSY, MYOCLONIC). Nocturnal myoclonus is the principal feature of the NOCTURNAL MYOCLONUS SYNDROME. (From Adams et al., Principles of Neurology, 6th ed, pp102-3).	Myoclonus, Action,Myoclonus, Nocturnal,Myoclonus, Palatal,Polymyoclonus,Myoclonic Jerk,Myoclonic Jerking,Myoclonus Simplex,Myoclonus, Eyelid,Myoclonus, Intention,Myoclonus, Lower Extremity,Myoclonus, Oculopalatal,Myoclonus, Segmental,Myoclonus, Sleep,Myoclonus, Upper Extremity,Action Myoclonus,Extremity Myoclonus, Lower,Extremity Myoclonus, Upper,Eyelid Myoclonus,Intention Myoclonus,Jerk, Myoclonic,Jerking, Myoclonic,Jerks, Myoclonic,Lower Extremity Myoclonus,Myoclonic Jerks,Nocturnal Myoclonus,Oculopalatal Myoclonus,Palatal Myoclonus,Segmental Myoclonus,Simplex, Myoclonus,Sleep Myoclonus,Upper Extremity Myoclonus
D010300	Parkinson Disease	A progressive, degenerative neurologic disease characterized by a TREMOR that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression. Pathologic features include loss of melanin containing neurons in the substantia nigra and other pigmented nuclei of the brainstem. LEWY BODIES are present in the substantia nigra and locus coeruleus but may also be found in a related condition (LEWY BODY DISEASE, DIFFUSE) characterized by dementia in combination with varying degrees of parkinsonism. (Adams et al., Principles of Neurology, 6th ed, p1059, pp1067-75)	Idiopathic Parkinson Disease,Lewy Body Parkinson Disease,Paralysis Agitans,Primary Parkinsonism,Idiopathic Parkinson's Disease,Lewy Body Parkinson's Disease,Parkinson Disease, Idiopathic,Parkinson's Disease,Parkinson's Disease, Idiopathic,Parkinson's Disease, Lewy Body,Parkinsonism, Primary
D010775	Photic Stimulation	Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.	Stimulation, Photic,Visual Stimulation,Photic Stimulations,Stimulation, Visual,Stimulations, Photic,Stimulations, Visual,Visual Stimulations
D010889	Piracetam	A compound suggested to be both a nootropic and a neuroprotective agent.	2-Pyrrolidone-N-Acetamide,Avigilen,Axonyl,Cerebroforte,Cerepar N,Ciclofalina,Cuxabrain,Dinagen,Gabacet,Geram,Memo-Puren,Nootrop,Nootropil,Nootropyl,Normabraïn,Piracebral,Piracetam AbZ,Piracetam-RPh,Piracetrop,Pirazetam,Pyracetam,Pyramem,Sinapsan,UCB-6215,Memo Puren,Piracetam RPh,UCB 6215,UCB6215
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D004569	Electroencephalography	Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.	EEG,Electroencephalogram,Electroencephalograms
D004576	Electromyography	Recording of the changes in electric potential of muscle by means of surface or needle electrodes.	Electromyogram,Surface Electromyography,Electromyograms,Electromyographies,Electromyographies, Surface,Electromyography, Surface,Surface Electromyographies