S89 the wrist to the cortex via pertinent ate points (upper extremity, brachial root, mesencephalon, thalamo-cortical and the motor cortex).
intermediplexus, radiation
A-4.08 EFFECTS OF PERIPHERAL .NERVE STIMULATION ON THE THERMOGRAM OF THE HAND. W.T. Liberson (Brooklyn, NY, USA) The infrared thermograms are usually recorded It might be of interest in clinical practice. to investigate the changes of regional temperatures under the influence of peripheral nerve stimulation, presumably of the sympathetic Ten normal subjects , aged 20 to nerve fibers. None had any history or 75, were investigated. evidence of cerebral or peripheral nerve inElectrical stimulation was applied volvement. to the median nerve at the arm. The parameters of stimulation were 40/set, 100 psec pulse duration and the current intensity below the threshold of contraction of the corresponding The duration of stimulation varied muscles. from 1 to 10 min. All subjects showed a decrease in temperature of the palmar aspect of the hand, particularly the tips of the fingers. The shift of the temperature was about 20 C. It persisted for several minutes after the end of.stimulation with. in certain subjects. a relative increase of-temperature foliowing the end of the cooling effect. These changes are both direct and reflex, inasmuch as they are also present in the contralateral hand, but to a considerabDirect recording of the temly lesser degree. perature on the tip of a finger by a recording thermometer confirms these findings and shows a latency of the order of 0.5 min. C-13.04 TERNS.
MODIFICATION OF INDUCED SEIZURE PATR.D.H. Maxwell (Wakefield, G.B.)
The pattern of the induced seizure contains three identifiable phases. Phase A. Following an effective depolarization resultinq in a short suppression of cortical activity, the duration is a function of the fit threshold and is subject to analeptic modification. There is a similar effect with drug-induced ictus. Electrical excitation of longer duration rings the cortex into response. B. The ictal phase is characterised by a cortical excitation which is the ictal activator. It results in secondary subcortical responses which provide the somatic This may be facilitated or modified component. by certain drugs which may be categorized by their effect upon these seizure components. C. The recovery phase can be modified in duration, which is probably a metabolic function. These responses are presented, together with the factors involved in producing modifications of them.
A-14.02 RECENT DEVELOPMENTS IN AMBULATORY EEG G. Stores and P. Brankin (Oxford, MONITORING. G.B.) Recent technical advances have enabled EEG studies to include recording over days or weeks in EEG monitoring of this real-life situations. type is becoming a valuable technique in a variety of clinical situations in which traditional-forms of recording were unhelpful. The combination of EEG monitoring and other physiological measures (such as ECG, GSR or respiration) further extends the range of clinical possibilities. Examples will be presented of the use of prolonged ambulatory monitoring in the differential diagnosis of attacks of uncertain origin and in other diagnostic issues in children and adults with neuropsychiatric disorders, and in the investigation of precipitants of seizures, the evaluation of antiepileptic drug treatment and the study of sleep disorders, especially in relation to psychiatric disorder The use of and psychotropic drug treatment. such investigations in non-specialized settings as well as special neuropsychiatric or epilepsy centres will be discussed. As long-term monitoring usually presents problems of obtaining art+ fact-free records and of analysing large amounts of data, solutions to these and other technical problems will also be considered. D-3.09 CONTRIBUTION OF EMOTIONAL AND POSTURAL AN ELECTROFACTORS TO FACIAL NhCLE ACTIVITY: PHYSIOLOGICAL STUDY IN MAN. M. Bratzlavsky and H. Vander Eecken (Ghent, Belgium) Among the different facial muscles, the periorbital musculature is of particular importance for the control of mimicry. In normal subjects the frontalis and orbicularis oculi muscles display a slight tonic EMG activity at rest. During emotional stress this activity is greatly enhanced. The present study was aimed at comparing the influence of head and body positions on the tonic periorbital EMG in relaxed conditions and in situations of emotional stress. At rest, horizontal rotation of the head induces tonic neck reflexes in the frontalis and orbicularis oculi, favoring widening of the palpebra1 fissure at the side toward which the head is rotated and narrowing of the opposite palpebra1 fissure. In the same circumstances, inclinations of the head and the body of the subjects with fixed neck around a bitemporal axis fails to indicate otolithic influences on the periorbital facial muscles. In emotional stress situations. the tonic effects of cervical oriain are potentiated, while evidence is provided 0; tonic vestibular reflexes in the frontalis and orbicularis oculi muscles. The observations suggest that facial muscle activity related to mimicry is dependent on the convergence of emotional and postural influences on facial motoneurons.