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EEG in the so-called vegetative state
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Total course of Group C was more rapid and generalized status epilepticus started within 20 days. Histo-pathological study revealed an extensive degenerative lesion in the injected hiuoocamous and sliqht ischemic modifications in'both amygdalas. This model of eoilepsv is compared with the kindling phenomenon'; it may be useful for understanding not only the constitution of the amygdaloid epileptic focus but also secondary generalization from the local amygdaloid seizure. B-16.05 PROCONVULSANT EFFECT OF B-CARBOLINE-3CARBOXYLIC AC10 ETHYL ESTER. J. Rossier, C. Cepeda and T. Tanaka (Gif-sur-Yvette, France) B-carboline-3-carboxylic acid ethyl ester (BCCE), a substance probably related to the endogenous ligand for benzodiazepine receptors, was tested on two models of epilepsy in the kainic acid induced limbic baboon Papio Papio: status epilepticus and photically induced epilepsy. Intravenous administration of B-CCE from 8 pg/kg to lOOug/kyproduced:l)areactivation ofepileptic phenomena in tie baboon with an experimentally induced irritative focus in the limbic structures, 2) latency shortening of the initial myoclonic response to intermittent ohotic stimulation in naturally photosensitive baboons and 3) photomyoclonic seizures or photically induced generalized convulsions in photosensitive or non-photosensitive baboons according to the dose. The proconvulsant role of B-CCE may berelatedto the activation of a particular class of benzodiazepine receptors. D-11.02 BRAIN-STEM AUDITORY EVOKED POTENTIALS: INVESTIGATION OF LATENCY-AMPLITUDE DIFFERENCES FROM IPSILATERAL AND CONTRALATERAL EAR DERIVATIONS. C.W. Erwin (Durham, N. Car., USA) Early latency, far-field, auditory evoked responses following monuaural stimulation show different component amplitudes and latencies depending on electrode'derivation. To aid in the identification of waves I throuqh V as recorded for Cz - Ai (Ai = ipsilaterallear), it is common practice to simultaneously record Comfrom C, - Ac (Ac = contralateral ear). pared to the ipsilateral derivation, the contralateral derivation shows consistently different latencies and amplitudes of all waves (I through VII). Recent reports suggest latency differences are due to presence of activity in ipsilateral and contralateral pathways with different conduction velocities producing different There is further suggestion source potentials. of clinical value in analysing latencies from both derivations with resulting increased test
sensitivity. We investigated the hypothesis of differently oriented segmental dipoles to explain the amplitude and latency differences. Responses to prolonged monaural rerefaction click stimuli were recorded simultaneously in six channels with 20 psec dwell time in human subDerivations included: Cz-Ai, Cz-A,, jects. C,-R (ankle), Ai-R, A,-R and Ai-Ac. Analysis of data revealed marked differ&c& at Ai-and A, extending throughout the sweep. Results are consistent with the hypothesis of single source generators and do not require supposition of separate bilaterally active pathways. C-11.05 EEG IN THE SO-CALLED VEGETATIVE STATE. H. Ishizaki and K. Minami (Osaka, Japan)
In 18 cases in the so-called vegetative state the EEGs were analysed: 6 cases were of cerebral infarction, 4 cases were of cerebral hemorrhage, 7 cases had head injury and one the rupture of an arterial aneurysm, Twenty cases (excluding cerebral infarction) were operated on. All patients were between 39 and 80 The results as follows: 11 low voltaae years. poor alpha rhythm; 2) delta and theta activiti 3) low voltage theta activity. The EEG basic rhythms of some cases were analysed by computer. These three types raise the problem of whether there were certain differences or not in the degree of the vegetative state. C-13.03 CORTICAL LAMIl!AR ANALYSIS OF VISUAL EVOKED POTENTIALS (VEPs) IN FELINE GENERALIZED R. Chemello, A. PellePENICILLIN EPILEPSY. grini, D. Giaretta, M. Ermani, L. Zanotto and G. Testa (Padua, Italy) VEPs were recorded from the cat visual cortex before and during generalized penicillin epilepsy by a microelectrode pushed through the cortex from surface to 2000 pm depth, by 100 pm Flash stimuli, delivered at 0.5 c/set steps. in normal cats and in the interburst periods after penicillin, were automatically triggered by the spikes during spike and wave (s-w) bursts, with such a delay that VEPs were reCortical profiles of corded during the wave. VEPs obtained in these different experimental situations were also analysed by the current source density analysis method. Before penicillin an early large sink was consistently found at 1100-1400 pm depth, followed by smaller sinks at more superficial levels (500-800 urn), and, with a longer delay (1 150 msec), by even smaller long-lasting sinks at 200-300 pm. After i.m. penicillin injection, during the interburst periods, the early large sink was replaced by multiple sinks at different depths (500-600 pm, 800-1100 pm, 1600 urn) followed at these same levels by an alternating of large sources and
Total course of Group C was more rapid and generalized status epilepticus started within 20 days. Histo-pathological study revealed an extensive degenerative lesion in the injected hiuoocamous and sliqht ischemic modifications in'both amygdalas. This model of eoilepsv is compared with the kindling phenomenon'; it may be useful for understanding not only the constitution of the amygdaloid epileptic focus but also secondary generalization from the local amygdaloid seizure. B-16.05 PROCONVULSANT EFFECT OF B-CARBOLINE-3CARBOXYLIC AC10 ETHYL ESTER. J. Rossier, C. Cepeda and T. Tanaka (Gif-sur-Yvette, France) B-carboline-3-carboxylic acid ethyl ester (BCCE), a substance probably related to the endogenous ligand for benzodiazepine receptors, was tested on two models of epilepsy in the kainic acid induced limbic baboon Papio Papio: status epilepticus and photically induced epilepsy. Intravenous administration of B-CCE from 8 pg/kg to lOOug/kyproduced:l)areactivation ofepileptic phenomena in tie baboon with an experimentally induced irritative focus in the limbic structures, 2) latency shortening of the initial myoclonic response to intermittent ohotic stimulation in naturally photosensitive baboons and 3) photomyoclonic seizures or photically induced generalized convulsions in photosensitive or non-photosensitive baboons according to the dose. The proconvulsant role of B-CCE may berelatedto the activation of a particular class of benzodiazepine receptors. D-11.02 BRAIN-STEM AUDITORY EVOKED POTENTIALS: INVESTIGATION OF LATENCY-AMPLITUDE DIFFERENCES FROM IPSILATERAL AND CONTRALATERAL EAR DERIVATIONS. C.W. Erwin (Durham, N. Car., USA) Early latency, far-field, auditory evoked responses following monuaural stimulation show different component amplitudes and latencies depending on electrode'derivation. To aid in the identification of waves I throuqh V as recorded for Cz - Ai (Ai = ipsilaterallear), it is common practice to simultaneously record Comfrom C, - Ac (Ac = contralateral ear). pared to the ipsilateral derivation, the contralateral derivation shows consistently different latencies and amplitudes of all waves (I through VII). Recent reports suggest latency differences are due to presence of activity in ipsilateral and contralateral pathways with different conduction velocities producing different There is further suggestion source potentials. of clinical value in analysing latencies from both derivations with resulting increased test
sensitivity. We investigated the hypothesis of differently oriented segmental dipoles to explain the amplitude and latency differences. Responses to prolonged monaural rerefaction click stimuli were recorded simultaneously in six channels with 20 psec dwell time in human subDerivations included: Cz-Ai, Cz-A,, jects. C,-R (ankle), Ai-R, A,-R and Ai-Ac. Analysis of data revealed marked differ&c& at Ai-and A, extending throughout the sweep. Results are consistent with the hypothesis of single source generators and do not require supposition of separate bilaterally active pathways. C-11.05 EEG IN THE SO-CALLED VEGETATIVE STATE. H. Ishizaki and K. Minami (Osaka, Japan)
In 18 cases in the so-called vegetative state the EEGs were analysed: 6 cases were of cerebral infarction, 4 cases were of cerebral hemorrhage, 7 cases had head injury and one the rupture of an arterial aneurysm, Twenty cases (excluding cerebral infarction) were operated on. All patients were between 39 and 80 The results as follows: 11 low voltaae years. poor alpha rhythm; 2) delta and theta activiti 3) low voltage theta activity. The EEG basic rhythms of some cases were analysed by computer. These three types raise the problem of whether there were certain differences or not in the degree of the vegetative state. C-13.03 CORTICAL LAMIl!AR ANALYSIS OF VISUAL EVOKED POTENTIALS (VEPs) IN FELINE GENERALIZED R. Chemello, A. PellePENICILLIN EPILEPSY. grini, D. Giaretta, M. Ermani, L. Zanotto and G. Testa (Padua, Italy) VEPs were recorded from the cat visual cortex before and during generalized penicillin epilepsy by a microelectrode pushed through the cortex from surface to 2000 pm depth, by 100 pm Flash stimuli, delivered at 0.5 c/set steps. in normal cats and in the interburst periods after penicillin, were automatically triggered by the spikes during spike and wave (s-w) bursts, with such a delay that VEPs were reCortical profiles of corded during the wave. VEPs obtained in these different experimental situations were also analysed by the current source density analysis method. Before penicillin an early large sink was consistently found at 1100-1400 pm depth, followed by smaller sinks at more superficial levels (500-800 urn), and, with a longer delay (1 150 msec), by even smaller long-lasting sinks at 200-300 pm. After i.m. penicillin injection, during the interburst periods, the early large sink was replaced by multiple sinks at different depths (500-600 pm, 800-1100 pm, 1600 urn) followed at these same levels by an alternating of large sources and