Electrophysiologic Analysis of a Chronic Seizure Model After Unilateral Hippocampal KA Injection

Summary: Purpose: Unilateral intrahippocampal injections of kainic acid (KA) in rats produce spontaneous recurrent limbic seizures and morphologic changes in hippocampus that resemble hippocampal sclerosis in patients with medically refractory mesial temporal lobe epilepsy (MTLE), that form of temporal lobe epilepsy (TLE) associated with hippocampal sclerosis. Interictal in vivo electrophysiologic studies have revealed high‐frequency (250‐500 Hz) oscillations, termed fast ripples (FRs). These oscillations may uniquely occur in or adjacent to the site of hippocampal KA injection, in areas that generate spontaneous seizures. Similar field potentials also have been demonstrated in the epileptogenic region of patients with TLE. We have now characterized ictal electrographic patterns in this rat model for comparison with those in human TLE and begun to evaluate the role of FRs in the transition to ictus in the KA‐treated rat.

[1]  Charles L. Wilson,et al.  Hippocampal and Entorhinal Cortex High‐Frequency Oscillations (100–500 Hz) in Human Epileptic Brain and in Kainic Acid‐Treated Rats with Chronic Seizures , 1999, Epilepsia.

[2]  Charles L. Wilson,et al.  High‐frequency oscillations in human brain , 1999, Hippocampus.

[3]  C. Wilson,et al.  Paired pulse suppression and facilitation in human epileptogenic hippocampal formation , 1998, Epilepsy Research.

[4]  Martin Straume,et al.  Temporal distribution of partial seizures: Comparison of an animal model with human partial epilepsy , 1998, Annals of neurology.

[5]  T. Babb,et al.  In contrast to kindled seizures, the frequency of spontaneous epilepsy in the limbic status model correlates with greater aberrant fascia dentata excitatory and inhibitory axon sprouting, and increased staining for N-methyl-d-aspartate, AMPA and GABAA receptors , 1997, Neuroscience.

[6]  Gary W. Mathern,et al.  Neuron loss, mossy fiber sprouting, and interictal spikes after intrahippocampal kainate in developing rats , 1996, Epilepsy Research.

[7]  A. Murro,et al.  The significance of ictal depth EEG patterns in patients with temporal lobe epilepsy. , 1996, Electroencephalography and clinical neurophysiology.

[8]  J. Engel.  Excitation and Inhibition in Epilepsy , 1996, Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques.

[9]  J. Geraedts,et al.  Application of micro-FISH to delineate deletions. , 1996, Cytogenetics and cell genetics.

[10]  Julio Cesar Sampaio P. Leite,et al.  Reactive synaptogenesis and neuron densities for neuropeptide Y, somatostatin, and glutamate decarboxylase immunoreactivity in the epileptogenic human fascia dentata , 1995, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[11]  G Buzsáki,et al.  Dentate EEG spikes and associated interneuronal population bursts in the hippocampal hilar region of the rat. , 1995, Journal of neurophysiology.

[12]  T L Babb,et al.  Influence of the type of initial precipitating injury and at what age it occurs on course and outcome in patients with temporal lobe seizures. , 1995, Journal of neurosurgery.

[13]  T L Babb,et al.  Quantified patterns of mossy fiber sprouting and neuron densities in hippocampal and lesional seizures. , 1995, Journal of neurosurgery.

[14]  S. Spencer,et al.  Invasive electroencephalography in mesial temporal lobe epilepsy. , 1995, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[15]  D. Dinner,et al.  Mesial temporal lobe epilepsy. , 1995, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[16]  D. Spencer,et al.  Entorhinal‐Hippocampal Interactions in Medial Temporal Lobe Epilepsy , 1994, Epilepsia.

[17]  T L Babb,et al.  Hippocampal EEG excitability and chronic spontaneous seizures are associated with aberrant synaptic reorganization in the rat intrahippocampal kainate model. , 1993, Electroencephalography and clinical neurophysiology.

[18]  T. Freund,et al.  Selective neuronal death in the contralateral hippocampus following unilateral kainate injections into the CA3 subfield , 1993, Neuroscience.

[19]  S. Spencer,et al.  Anatomic Correlates of Interhippocampal Seizure Propagation Time , 1992, Epilepsia.

[20]  G W Somes,et al.  Long-term ictal monitoring with subdural strip electrodes: prognostic factors for selecting temporal lobectomy candidates. , 1992, Journal of neurosurgery.

[21]  S. Spencer,et al.  Morphological Patterns of Seizures Recorded Intracranially , 1992, Epilepsia.

[22]  T. Babb,et al.  Synaptic reorganization by mossy fibers in human epileptic fascia dentata , 1991, Neuroscience.

[23]  J. Engel,et al.  The Hans Berger lecture. Functional explorations of the human epileptic brain and their therapeutic implications. , 1990, Electroencephalography and clinical neurophysiology.

[24]  T. Babb,et al.  Sprouting of GABAergic and mossy fiber axons in dentate gyrus following intrahippocampal kainate in the rat , 1990, Experimental Neurology.

[25]  J. Pretorius,et al.  Glutamate decarboxylase-immunoreactive neurons are preserved in human epileptic hippocampus , 1989, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[26]  O. Prohaska,et al.  Multisite recording of brain field potentials and unit activity in freely moving rats , 1989, Journal of Neuroscience Methods.

[27]  F. Dudek,et al.  Chronic seizures and collateral sprouting of dentate mossy fibers after kainic acid treatment in rats , 1988, Brain Research.

[28]  G. Buzsáki.  Hippocampal sharp waves: Their origin and significance , 1986, Brain Research.

[29]  T L Babb,et al.  Interhemispheric Propagation Time of Human Hippocampal Seizures: II. Relationship to Pathology and Cell Density , 1986, Epilepsia.

[30]  T L Babb,et al.  Interhemispheric Propagation Time of Human Hippocampal Seizures , 1986, Epilepsia.

[31]  Y. Ben-Ari,et al.  Limbic seizure and brain damage produced by kainic acid: Mechanisms and relevance to human temporal lobe epilepsy , 1985, Neuroscience.

[32]  G. Paxinos,et al.  The Rat Brain in Stereotaxic Coordinates , 1983 .

[33]  D. Riche,et al.  Long-term effects of intrahippocampal kainic acid injection in rats: a method for inducing spontaneous recurrent seizures. , 1982, Electroencephalography and clinical neurophysiology.

[34]  Nadler Jv.  Kainic acid as a tool for the study of temporal lobe epilepsy , 1981 .

[35]  W. J. Brown,et al.  Neuropathological Findings Following Temporal Lobectomy Related to Surface and Deep EEG Patterns , 1981, Epilepsia.

[36]  J. Nadler.  Minireview. Kainic acid as a tool for the study of temporal lobe epilepsy. , 1981, Life sciences.

[37]  R. Racine,et al.  Modification of seizure activity by electrical stimulation. II. Motor seizure. , 1972, Electroencephalography and clinical neurophysiology.