Neurophysiological observations in patients with epilepsy

• Published in: Brain and nerve = Shinkei kenkyū no shinpo Vol. 65; no. 5; p. 521
• Main Author: Ugawa, Yoshikazu
• Format: Journal Article
• Language: Japanese
• Published: Japan 01.05.2013
• Subjects: Animals; Anticonvulsants - therapeutic use; Electroencephalography - methods; Epilepsy - drug therapy; Epilepsy - physiopathology; Humans; Ion Channels - metabolism; Neuronal Plasticity
• ISSN: 1881-6096

In this paper, I briefly summarize what have been shown by physiological studies in human epileptic patients. My main message is that "epilepsy is simple and clear" based on our knowledge of cell physiology. The pathophysiological mechanisms, genetic abnormalities and mechanisms of action of used antiepileptic drugs are all consistent with our basic medical knowledge. I summarize three points as follows. UNDERLYING PATHOPHYSIOLOGY OF EPILEPSY: Epilepsy is produced by synchronous, abnormal excessive discharges of some human brain structure. Such discharges are induced by abnormalities in ion channels, neurotransmitters, transmitter receptors or gap junctions; related genetic abnormalities have been reported in some familial epilepsy disorders. WHAT PHYSIOLOGICAL ABNORMALITIES HAVE BEEN SHOWN IN EPILEPTIC PATIENTS? Epileptic spikes in electroencephalography may be one kind of synchronous excessive discharges. Giant SEP reflects hyperexcitability of the sensory cortex (S1) to a single stimulus, and paired stimulation SEP showed inhibitory control reduction of S1. TMS of the primary motor cortex (M1) also revealed hyperexcitability and GABAergic inhibitory reduction of M1. PHYSIOLOGICAL MECHANISMS OF ACTION OF EPILEPTIC DRUGS: TMS studies have been performed in normal subjects taking a certain antiepileptic drug. Some drugs function as sodium or calcium channel blockers, others enhance GABAergic function or modulate neuro-plastic functions. I hope that this article give you an impression of "epilepsy is easy and clear".