## Abstract Unique high‐frequency oscillations of 250 to 500Hz, termed __fast ripples__, have been identified in seizure‐generating limbic areas in rats made epileptic by intrahippocampal injection of kainic acid, and in patients with mesial temporal lobe epilepsy. In the rat, fast ripples clearly
High-frequency oscillations in human brain
✍ Scribed by Anatol Bragin; Jerome Engel Jr; Charles L. Wilson; Itzhak Fried; Gyorgy Buzsáki
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 137 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1050-9631
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✦ Synopsis
Ripples are 100-200 Hz short-duration oscillatory field potentials that have recently been recorded in rat hippocampus and entorhinal cortex. They reflect fast IPSPs on the soma of pyramidal cells, which occur during synchronous afferent excitation of principal cells and interneuron networks. We now describe two similar types of highfrequency field oscillations recorded from the entorhinal cortex and hippocampus of patients with mesial temporal lobe epilepsy. The first type appears be the human equivalent of normal ripples in the rat. The second, which we have termed fast ripples (FR), are in the frequency range of 250-500 Hz. FR are found in the epileptogenic region and may reflect pathological hypersynchronous population spikes of bursting pyramidal cells.
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