Optical analysis of acute spontaneous epileptiform discharges in the in vivo rat cerebral cortex

Miyakawa, Naohisa; Yazawa, Itaru; Sasaki, Shinichi; Momose‐Sato, Yoko; Sato, Katsushige

doi:10.1016/s1053-8119(02)00056-3

Cited by 16 publications

(18 citation statements)

References 41 publications

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“…Finally, 4) the choice of anesthesia (isofluorane) might also be of importance. Indeed, shorter interictal spikes (ϳ300 ms) are usually found both in humans and in animal studies using urethane and/or ketamine/xylazine anesthesia (Hirase et al 2004;Ma et al 2009a;Miyakawa et al 2003) as compared with halogenate anesthesia (e.g., halothane anesthesia in ferrets yields LFP responses of similar duration as those we report) (Schwartz and Bonhoeffer 2001).…”

Section: Predictive Power Of the Model-linearity Rangesupporting

confidence: 71%

Investigation of Linear Coupling Between Single-Event Blood Flow Responses and Interictal Discharges in a Model of Experimental Epilepsy

Vanzetta

Flynn

Ivanov

et al. 2010

Journal of Neurophysiology

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Vanzetta I, Flynn C, Ivanov AI, Bernard C, Bénar CG. Investigation of linear coupling between single-event blood flow responses and interictal discharges in a model of experimental epilepsy. J Neurophysiol 103: 3139 -3152, 2010. First published March 24, 2010 doi:10.1152/jn.01048.2009. A successful outcome of epilepsy neurosurgery relies on an accurate delineation of the epileptogenic region to be resected. Functional magnetic resonance imaging (fMRI) would allow doing this noninvasively at high spatial resolution. However, a clear, quantitative description of the relationship between hemodynamic changes and the underlying epileptiform neuronal activity is still missing, thereby preventing the systematic use of fMRI for routine epilepsy surgery planning. To this aim, we used a local epilepsy model to record simultaneously cerebral blood flow (CBF) with laser Doppler (LD) and local field potentials (LFP) in rat frontal cortex. CBF responses to individual interictal-like spikes were large and robust. Their amplitude correlated linearly with spike amplitude. Moreover, the CBF response added linearly in time over a large range of spiking rates. CBF responses could thus be predicted by a linear model of the kind currently used for the interpretation of fMRI data, but including also the spikes' amplitudes as additional information. Predicted and measured CBF responses matched accurately. For high spiking frequencies (above ϳ0.2 Hz), the responses saturated but could eventually recover, indicating the presence of multiple neurovascular coupling mechanisms, which might act at different spatiotemporal scales. Spatially, CBF responses peaked at the center of epileptic activity and displayed a spatial specificity at least as good as the millimeter. These results suggest that simultaneous electroencephalographic and blood flow-based fMRI recordings should be suitable for the noninvasive precise localization of hyperexcitable regions in epileptic patients candidate for neurosurgery.

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Section: Predictive Power Of the Model-linearity Rangesupporting

confidence: 71%

Investigation of Linear Coupling Between Single-Event Blood Flow Responses and Interictal Discharges in a Model of Experimental Epilepsy

Vanzetta

Flynn

Ivanov

et al. 2010

Journal of Neurophysiology

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“…It was focused on the preparation by means of a bright-field condenser with a numerical aperture (NA) matched to that of the microscope objective (S plan Apo: 2ϫ, 0.08 NA; 10ϫ, 0.4 NA). The optical signals were recorded at a sampling rate of 0.941 ms per frame using a photodiode array (PDA) with 464 channels arranged hexagonally (Miyakawa et al, 2003; Momose-Sato et A, Schema of a sagittal section of the chick telencephalon (L1.5), which depicts the related structures. B, Photomicrograph of the section injected with the anterograde neural tracer BDA in the HDCo (white arrowhead) (n ϭ 5).…”

Section: Methodsmentioning

confidence: 99%

Demonstration of a Neural Circuit Critical for Imprinting Behavior in Chicks

Nakamori

Sato²,

Atoji³

et al. 2010

J. Neurosci.

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“…In published studies to date, diffuse reflectance optical imaging has been used frequently to monitor the hemodynamics of an epileptic lesion in vivo in both animal models of epilepsy and humans. 3,8,14,17,28,37,40,41,44,49,52,53 Although these results support the idea that the investigation of intrinsic physiological characteristics, especially hemodynamics, may be a viable alternative or addition to the current methods of epileptic lesion demarcation, the impact of such an approach on the outcome of epilepsy surgery has not yet been determined. Furthermore, the feasibility of using optical spectroscopy to delineate the margins of neocortical epileptic lesions in children has not yet been proven.…”

Section: Optical Spectroscopymentioning

confidence: 74%

“…The fluorescence and diffuse reflectance spectral features depict unique, static, in vivo characteristics of the epileptic cortex during the interictal period, which should not be confused with the dynamic diffuse reflectance features reported by other groups. 3,8,14,17,28,37,40,41,44,49,52,53 These observations warrant further studies to ascertain the clinical utility of optical spectroscopy in pediatric epilepsy surgery.…”

Section: Discussionmentioning

confidence: 89%

“…In other words, they provide only a snapshot of the physiological characteristics of the cortex during a 1-second integration time. The dynamic nature of brain metabolism and hemodynamics 3,8,14,17,28,37,40,41,44,49,52,53 is completely neglected in this statistical model. To address this potential shortcoming, we have designed and developed a new spectroscopic system that can be used to acquire broadband optical spectra (400-950 nm) from the brain at a rate of 33 Hz in a continuous manner.…”

Section: Neurosurg Focus / Volume 25 / September 2008mentioning

confidence: 99%

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The role of optical spectroscopy in epilepsy surgery in children

Bhatia

Ragheb

Johnson

et al. 2008

FOC

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Object Surgery is an important therapeutic modality for pediatric patients with intractable epilepsy. However, existing imaging and diagnostic technologies such as MR imaging and electrocochleography (ECoG) do not always effectively delineate the true resection margin of an epileptic cortical lesion because of limitations in their sensitivity. Optical spectroscopic techniques such as fluorescence and diffuse reflectance spectroscopy provide a nondestructive means of gauging the physiological features of the brain in vivo, including hemodynamics and metabolism. In this study, the authors investigate the feasibility of using combined fluorescence and diffuse reflectance spectroscopy to assist epilepsy surgery in children. Methods In vivo static fluorescence and diffuse reflectance spectra were acquired from the brain in children undergoing epilepsy surgery. Spectral measurements were obtained using a portable spectroscopic system in conjunction with a fiber optic probe. The optical investigations were conducted at the normal and abnormal cortex as defined by intraoperative ECoG and preoperative imaging studies. Biopsy samples were taken from the investigated sites located within the zone of resection. The optical spectra were classified into multiple subsets in accordance with the ECoG and histological study results. The authors used statistical comparisons between 2 given data subsets to identify unique spectral features. Empirical discrimination algorithms were developed using the identified spectral features to determine if the objective of the study was achieved. Results Fifteen pediatric patients were enrolled in this pilot study. Elevated diffuse reflectance signals between 500 and 600 nm and/or between 650 and 850 nm were observed commonly in the investigated sites with abnormal ECoG and/or histological features in 10 patients. The appearance of a fluorescent peak at 400 nm was observed in both normal and abnormal cortex of 5 patients. These spectral alterations were attributed to changes in morphological and/or biochemical characteristics of the epileptic cortex. The sensitivities and specificities of the empirical discrimination algorithms, which were constructed using the identified spectral features, were all > 90%. Conclusions The results of this study demonstrate the feasibility of using static fluorescence and diffuse reflectance spectroscopy to differentiate normal from abnormal cortex on the basis of intraoperative assessment of ECoG and histological features. It is therefore possible to use fluorescence and diffuse reflectance spectroscopy as an aid in epilepsy surgery.

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Optical analysis of acute spontaneous epileptiform discharges in the in vivo rat cerebral cortex

Cited by 16 publications

References 41 publications

Investigation of Linear Coupling Between Single-Event Blood Flow Responses and Interictal Discharges in a Model of Experimental Epilepsy

Investigation of Linear Coupling Between Single-Event Blood Flow Responses and Interictal Discharges in a Model of Experimental Epilepsy

Demonstration of a Neural Circuit Critical for Imprinting Behavior in Chicks

The role of optical spectroscopy in epilepsy surgery in children

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