The role of hippocampal commissures in the interhemispheric transfer of epileptiform afterdischarges in the rat: a study using linear and non-linear regression analysis

Lima, Vera Maura Fernandes de; Pijn, J.P.; Filipe, Carlos N.; Silva, Fernando Lopes da

doi:10.1016/0013-4694(90)90003-3

Cited by 51 publications

(24 citation statements)

References 24 publications

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“…If the relationship is linear, approximates the cross-correlation coefficient . This method was applied to EEG signals recorded during epileptiform seizures by Fernandes de Lima et al [22] and by Pijn et al [99]. The application of these quantitative analytical methods demonstrated that at the beginning of a seizure, considerable differences exist between and , indicating the presence of nonlinear relations between signals recorded from different sites, and that the propagation path of seizures may be detected if the very early part of the seizure is analyzed; later parts may show results that do not follow a clear pattern.…”

Section: Measuring Seizure Eeg Propagation: Linear and Nonlinear Mmentioning

confidence: 99%

The Impact of EEG/MEG Signal Processing and Modeling in the Diagnostic and Management of Epilepsy

Silva

2008

IEEE Rev. Biomed. Eng.

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Section: Measuring Seizure Eeg Propagation: Linear and Nonlinear Mmentioning

confidence: 99%

The Impact of EEG/MEG Signal Processing and Modeling in the Diagnostic and Management of Epilepsy

Silva

2008

IEEE Rev. Biomed. Eng.

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“…First, we reasoned that unilateral infusions might be sufficient to overcome the deficits produced by intra-septal infusions of muscimol because we and others have shown previously that unilateral manipulations of the hippocampus affect learning and memory and neurochemical indices (Packard et al 1994(Packard et al , 1996Cooper and Sofroniew 1996;Kimonides et al 1998;Packard and Teather 1998;Ragozzino et al 1998;Roozendaal et al 1999). Second, there are extensive connections among the two hippocampi and the two entorhinal cortices (Amaral et al 1984;Demeter et al 1985;Christesen and Sorensen 1989;Fernandes de Lima et al 1990;Gloor et al 1993). It is possible that infusing physostigmine in one hemisphere affects the hippocampus or entorhinal cortex bilaterally.…”

Section: Acetylcholine Gaba and Spontaneous Alternationmentioning

confidence: 99%

Increasing Acetylcholine Levels in the Hippocampus or Entorhinal Cortex Reverses the Impairing Effects of Septal GABA Receptor Activation on Spontaneous Alternation

Degroot¹,

Parent²

2000

Learn. Mem.

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Intra-septal infusions of the ␥-aminobutyric acid (GABA) agonist muscimol impair learning and memory in a variety of tasks. This experiment determined whether hippocampal or entorhinal infusions of the acetylcholinesterase inhibitor physostigmine would reverse such impairing effects on spontaneous alternation performance, a measure of spatial working memory. Male Sprague-Dawley rats were given intra-septal infusions of vehicle or muscimol (1 nmole/0.5 µL) combined with unilateral intra-hippocampal or intraentorhinal infusions of vehicle or physostigmine (10 µg/µL for the hippocampus; 7.5 µg/µL or 1.875 µg/0.25 µL for the entorhinal cortex). Fifteen minutes later, spontaneous alternation performance was assessed. The results indicated that intra-septal infusions of muscimol significantly decreased percentage-of-alternation scores, whereas intra-hippocampal or intra-entorhinal infusions of physostigmine had no effect. More importantly, intra-hippocampal or intra-entorhinal infusions of physostigmine, at doses that did not influence performance when administered alone, completely reversed the impairing effects of the muscimol infusions. These findings indicate that increasing cholinergic levels in the hippocampus or entorhinal cortex is sufficient to reverse the impairing effects of septal GABA receptor activation and support the hypothesis that the impairing effects of septal GABAergic activity involve cholinergic processes in the hippocampus and the entorhinal cortex.Extensive evidence has implicated the medial septum in learning and memory. Lesions of the medial septum impair acquisition and retention performance in a variety of behavioral paradigms (Mitchell et al. 1982;Bolhuis et al. 1988;Fibiger et al. 1991;M'Harzi and Jarrard 1992). Furthermore, memory can be enhanced or impaired by intra-septal infusions of drugs that act at a variety of neurotransmitter systems (Brioni et al. 1990;Givens and Olton 1990;Markowska et al. 1990). For example, intra-septal infusions of ␥-aminobutyric acid (GABA)ergic agonists impair memory during numerous tasks, including radial arm maze performance, inhibitory avoidance, water maze performance, spontaneous alternation, rewarded alternation, and visual discrimination (Brioni et

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“…To approach this problem, different analytical methods have been proposed. Some are based on comprehensive mathematical analyses of the EEG including Fast Fourier Transformation and cross-spectral phase/coherence estimation (Brazier, 1972;Gotman, 1983) as well as linear or non-linear correlation analyses (Cohn and Leader, 1967;Guilford and Fruchter, 1985;Pijn, Vijn, Lopes da Silva, Van Ende Boas and Blanes, 1990;Fernandes de Lima, Pijn, Nunes Filipe and Lopes da Silva, 1990). We used Gotman's method in our previous paper to study relationships between cortical and subcortical structures in epileptiform activity caused by picrotoxin in the rat (Medvedev, Mackenzie, Hiscock and Willoughby, 1996).…”

Section: T 50mentioning

confidence: 99%

Autoregressive Modeling of the Eeg in Systemic Kainic Acid-Induced Epileptogenesis

Medvedev

Willoughby

1999

International Journal of Neuroscience

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Background activity as well as three kinds of bilateral epileptiform discharges, recorded from the cerebral cortex and hippocampus of freely behaving rats treated with intravenous kainic acid (KA), were analysed by the directed transfer function (DTF) method within multivariate autoregressive modeling of the EEG. This method reveals statistical influence (flow of activity) between brain regions at different frequencies. There was no significant influence between rhythms in different brain regions in the background EEG. Early after KA administration, low frequency rhythms (< 10Hz) in the frontal cortex began to lead slow rhythms in other areas and high frequency rhythms (20-60 Hz), possibly gamma oscillations, intensified in the hippocampus. In spike-wave discharges, frontal cortex led both low and high frequency rhythms. Initially during generalised non-convulsive discharges, slow rhythms originated from frontal cortex and high frequency rhythms from hippocampus while later, slow rhythms as well, often arose from hippocampus. During the convulsive discharge, the flow of activity of dominant slow rhythms repeatedly changed between hippocampus and neocortex, with more frequent dominance of the hippocampus, while hippocampus continued to lead high frequency rhythms. We conclude that KA-induced epileptiform discharges are cortical and hippocampal events, specifically that the frontal cortex is early to express low frequency rhythms and the hippocampus, high frequency rhythms. More generally, the findings suggest that epileptiform discharges result from interacting rhythms of different frequencies that arise from different structures, and that gamma oscillations possibly contribute to widespread synchronisation during some forms of epileptogenesis.

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The role of hippocampal commissures in the interhemispheric transfer of epileptiform afterdischarges in the rat: a study using linear and non-linear regression analysis

Cited by 51 publications

References 24 publications

The Impact of EEG/MEG Signal Processing and Modeling in the Diagnostic and Management of Epilepsy

The Impact of EEG/MEG Signal Processing and Modeling in the Diagnostic and Management of Epilepsy

Increasing Acetylcholine Levels in the Hippocampus or Entorhinal Cortex Reverses the Impairing Effects of Septal GABA Receptor Activation on Spontaneous Alternation

Autoregressive Modeling of the Eeg in Systemic Kainic Acid-Induced Epileptogenesis

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