(BY RACHEL DERITA, PhD Candidate,Thomas Jefferson University, Department of Cancer Biology) Epileptic seizures are established to neuroscience as global excitation of neurons in the brain. However, new research from Jefferson (Philadelphia University & Jefferson University) in Philadelphia and collaborating institutions has uncovered a previously unknown period of time before an epileptic seizure in which there is an activation of inhibitory neurons. “This is the first time, to our knowledge, that this phenomenon of inhibition at the start of a seizure has been observed in humans,” states senior author of the study Shennan Weiss, MD, PhD, Assistant Professor of Neurology and Head of the Thomas Jefferson Computational Epilepsy Laboratory at the Vickie & Jack Farber Institute for Neuroscience at Jefferson. Before now, this was a phenomenon only observed in chemically-induced seizures in research animals, and was therefore considered an artifact of the experimental models. In the current study, published online on September 4, 2018, in the Annals of Neurology, surgeons collaborating between Jefferson and the University of California at Los Angeles (UCLA), used electrodes to determine the exact location of the seizures occurring in an epilepsy patient. They then were able to track action potentials from single neurons, classified as either excitatory or inhibitory. It was observed that there was a burst of activity from the inhibitory neurons prior to activity of the excitatory neurons. Epileptic patients often experience a period of time prior to a seizure characterized by auras, confusion, and an inability to speak clearly or form coherent sentences.
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