Human epileptic neurons studied in vitro

The in vitro neocortical brain slice technique was used to study electrophysiological properties of neurons from brain biopsies in 10 patients undergoing neurosurgical treatment for a variety of conditions, including focal epilepsy. The principal finding was the occurrence of orthodromically evoked depolarization shifts (DSs) and burst discharges in a proportion of neurons in slices from epileptogenic cortex. These evoked depolarizations and bursts had a number of properties in common with those from experimental epileptogenic foci in neocortex, including large amplitude and prolonged duration; long and variable latencies; and all or none, threshold type behavior, dependent on the parameters of orthodromic stimulation. Also DSs could not be evoked by intracellular stimulation, or blocked by hyperpolarizing current pulses once they had been orthodromically evoked. Responses of DSs to current thus differed markedly from those of neurons in epileptogenic guinea pig hippocampal slices. The results of these experiments suggest that intracellular events in human neurons involved in epileptogenesis are similar in appearance to those in various animal models. Neurons in chronic epileptogenesis are similar in appearance to those in various animal models. Neurons in chronic epileptogenic foci retain some of their abnormal properties within brain slices maintained in vitro.

[1]  R. Dingledine,et al.  Penicillin blocks hippocampal IPSPs, unmasking prolonged EPSPs , 1979, Brain Research.

[2]  E. Fetz,et al.  Neuronal activity in the chronic and acute epileptogenic focus. , 1974, Experimental neurology.

[3]  D. Prince,et al.  Cellular and field potential properties of epileptogenic hippocampal slices , 1978, Brain Research.

[4]  D. Prince,et al.  Intracellular recordings from chronic epileptogenic foci in the monkey. , 1970, Electroencephalography and clinical neurophysiology.

[5]  W H Calvin,et al.  Human cortical neurons in epileptogenic foci: comparison of inter-ictal firing patterns to those of "epileptic" neurons in animals. , 1973, Electroencephalography and clinical neurophysiology.

[6]  D. Prince,et al.  Intradendritic recordings from hippocampal neurons. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[7]  K. Skrede,et al.  The transverse hippocampal slice: a well-defined cortical structure maintained in vitro. , 1971, Brain research.

[8]  G F Ayala,et al.  Genesis of epileptic interictal spikes. New knowledge of cortical feedback systems suggests a neurophysiological explanation of brief paroxysms. , 1973, Brain research.

[9]  D. Prince,et al.  Epileptogenesis in neocortical slices , 1977, Brain Research.

[10]  N. Kawai,et al.  Seizure Discharges Evoked in Vitro in Thin Section from Guinea Pig Hippocampus , 1967, Science.

[11]  P. Schwartzkroin,et al.  Physiological and morphological identification of a nonpyramidal hippocampal cell type , 1978, Brain Research.

[12]  C. Yamamoto.  Intracellular study of seizure-like afterdischarges elicited in thin hippocampal sections in vitro. , 1972, Experimental neurology.

[13]  G. Ayala,et al.  Neuronal behavior and triggering mechanism in cortical epileptic focus. , 1969, Journal of neurophysiology.

[14]  R K Wong,et al.  Dendritic mechanisms underlying penicillin-induced epileptiform activity. , 1979, Science.

[15]  D. Prince,et al.  Modification of Focal Cortical Epileptogenic Discharge by Afferent Influences , 1966, Epilepsia.

[16]  D. Prince,et al.  Participation of calcium spikes during intrinsic burst firing in hippocampal neurons , 1978, Brain Research.

[17]  D. Prince,et al.  Changes in excitatory and inhibitory synaptic potentials leading to epileptogenic activity , 1980, Brain Research.

[18]  C. A. Marsan,et al.  CORTICAL CELLULAR PHENOMENA IN EXPERIMENTAL EPILEPSY: INTERICTAL MANIFESTATIONS. , 1964, Experimental neurology.

[19]  D. Prince,et al.  Penicillin‐induced epileptiform activity in the hippocampal in vitro preparation , 1977, Annals of neurology.

[20]  D. Prince.  The depolarization shift in "epileptic" neurons. , 1968, Experimental neurology.

[21]  H. Matsumoto,et al.  INTRACELLULAR EVENTS DURING THE ACTIVATION OF CORTICAL EPILEPTIFORM DISCHARGES. , 1964, Electroencephalography and clinical neurophysiology.