Quantitative analysis of high-frequency oscillations (80-500 Hz) recorded in human epileptic hippocampus and entorhinal cortex
- PMID: 12364503
- DOI: 10.1152/jn.2002.88.4.1743
Quantitative analysis of high-frequency oscillations (80-500 Hz) recorded in human epileptic hippocampus and entorhinal cortex
Abstract
High-frequency oscillations (100-200 Hz), termed ripples, have been identified in hippocampal (Hip) and entorhinal cortical (EC) areas of rodents and humans. In contrast, higher-frequency oscillations (250-500 Hz), termed fast ripples (FR), have been described in seizure-generating limbic areas of rodents made epileptic by intrahippocampal injection of kainic acid and observed in humans ipsilateral to areas of seizure initiation. However, quantitative studies supporting the existence of two spectrally distinct oscillatory events have not been carried out in humans nor has the preferential appearance of FR within seizure generating areas received statistical evaluation based on analysis of a large sample of oscillatory events. Interictal oscillations within the bandwidth of 80-500 Hz were detected in Hip and EC areas of patients with mesial temporal lobe epilepsy using wideband EEG recorded during non-rapid eye-movement sleep from chronically implanted depth electrodes. Power spectral analysis showed that oscillations detected from Hip and EC areas were composed of two spectrally distinct groups. The lower-frequency ripple group was defined by a frequency of 96 +/- 14 Hz (median +/- width), while the higher-frequency FR group had a frequency of 262 +/- 59 Hz. FR oscillations were significantly shorter in duration compared with ripple oscillations (P < 0.0001). In regard to the occurrence of FR and ripples in epileptic Hip and EC, the mean ratio of the number of FR to ripples generated in areas ipsilateral to seizure onset was significantly higher compared with the mean ratio of FR to ripple generation from contralateral areas (P = 0.008). Furthermore, sites ipsilateral to seizure onset with hippocampal atrophy had significantly higher ratios compared with sites contralateral to both seizure onset and hippocampal atrophy (P = 0.001). These data provide compelling quantitative and statistical evidence for the existence of two spectrally distinct groups of limbic oscillations that have frequency and duration characteristics similar to those previously described in epileptic rat and human Hip and EC. The strong association between FR and regions of seizure initiation supports the view that FR reflects pathological hypersynchronous events crucially associated with seizure genesis.
Similar articles
-
Interictal high-frequency oscillations (80-500 Hz) in the human epileptic brain: entorhinal cortex.Ann Neurol. 2002 Oct;52(4):407-15. doi: 10.1002/ana.10291. Ann Neurol. 2002. PMID: 12325068
-
Increased fast ripple to ripple ratios correlate with reduced hippocampal volumes and neuron loss in temporal lobe epilepsy patients.Epilepsia. 2007 Nov;48(11):2130-8. doi: 10.1111/j.1528-1167.2007.01225.x. Epub 2007 Jul 28. Epilepsia. 2007. PMID: 17662059
-
Hippocampal and entorhinal cortex high-frequency oscillations (100--500 Hz) in human epileptic brain and in kainic acid--treated rats with chronic seizures.Epilepsia. 1999 Feb;40(2):127-37. doi: 10.1111/j.1528-1157.1999.tb02065.x. Epilepsia. 1999. PMID: 9952257
-
High-frequency oscillations: what is normal and what is not?Epilepsia. 2009 Apr;50(4):598-604. doi: 10.1111/j.1528-1167.2008.01917.x. Epub 2008 Dec 4. Epilepsia. 2009. PMID: 19055491 Review.
-
Specific imbalance of excitatory/inhibitory signaling establishes seizure onset pattern in temporal lobe epilepsy.J Neurophysiol. 2016 Jun 1;115(6):3229-37. doi: 10.1152/jn.01128.2015. Epub 2016 Apr 13. J Neurophysiol. 2016. PMID: 27075542 Free PMC article. Review.
Cited by
-
Net synaptic drive of fast-spiking interneurons is inverted towards inhibition in human FCD I epilepsy.Nat Commun. 2024 Aug 6;15(1):6683. doi: 10.1038/s41467-024-51065-7. Nat Commun. 2024. PMID: 39107293 Free PMC article.
-
Intan Technologies integrated circuits can produce analog-to-digital conversion artifacts that affect neural signal acquisition.J Neural Eng. 2024 Jul 9;21(4):10.1088/1741-2552/ad5762. doi: 10.1088/1741-2552/ad5762. J Neural Eng. 2024. PMID: 38865993
-
PyHFO: lightweight deep learning-powered end-to-end high-frequency oscillations analysis application.J Neural Eng. 2024 May 28;21(3):036023. doi: 10.1088/1741-2552/ad4916. J Neural Eng. 2024. PMID: 38722308 Free PMC article.
-
The detection of absence seizures using cross-frequency coupling analysis with a deep learning network.Res Sq [Preprint]. 2024 Apr 10:rs.3.rs-4178484. doi: 10.21203/rs.3.rs-4178484/v1. Res Sq. 2024. PMID: 38659733 Free PMC article. Preprint.
-
High frequency oscillation network dynamics predict outcome in non-palliative epilepsy surgery.Brain Commun. 2024 Feb 7;6(1):fcae032. doi: 10.1093/braincomms/fcae032. eCollection 2024. Brain Commun. 2024. PMID: 38384998 Free PMC article.
Publication types
MeSH terms
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources