Electroencephalography and clinical neurophysiology
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Electroencephalogr Clin Neurophysiol · Dec 1980
Short latency somatosensory evoked potentials from radial, median and ulnar nerve stimulation in man.
Short latency somatosensory evoked potentials (SEPs) were elicited by stimulation at the wrist of median, radial, and ulnar nerves, singly or in combination, using normal subjects. Amplitude of P10 was strikingly lower with radial stimulation than with median stimulation, while ulnar-derived P10 was intermediate in amplitude. This difference probably reflects the antidromic firing of motor fibers contained in median nerves as compared with the superficial branch of radial nerve, which is entirely sensory. ⋯ With simultaneous stimulation of several nerves within one arm, larger potentials were sometimes achieved but with poorer definition of P12 and P14. The clinical utility of radial, ulnar, and median stimulation for localizing peripheral lesions derives from the distinct anatomical pathways of the stimulated fibers through the brachial plexus and from the separable motor and sensory components of P10. SEP is less invasive than EMG; this fact, plus its freedom from sampling error, make it potentially more suitable than conventional EMG for sequentially following a patient's clinical course.
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Electroencephalogr Clin Neurophysiol · Dec 1979
A microdrive for use with glass or metal microelectrodes in recording from freely-moving rats.
A new subminiature microdrive assembly is described for electrophysiological recording from behaving rats. This very small, lightweight system allows excellent precision in electrode placement and can maintain stable recordings over extended periods. Since the electrode is nonrotating, tissue damage is minimized. Either metal or glass microelectrodes may be used with the system, offering the possibility of iontophoresis for cell marking or neuropharmacological manipulations.
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In 30 patients, who were all comatose as a result of cerebral anoxia after cardiac arrest, at least one EEG with activity in the alpha frequency range was recorded. Regionally the activity of the above mentioned characteristic was often diffusely distributed or most pronounced occipitally, whereas a tendency to affect other regions was rarely observed. ⋯ Only one of the patients survived, and even so, with considerable mental defects. In 4 patients the level of consciousness improved, but 3 of them never reached a definite level of cortical function and died as a result of cerebral anoxia.