Fast and Localized Event-Related Optical Signals (EROS) in the Human Occipital Cortex: Comparisons with the Visual Evoked Potential and fMRI

Gratton, Gabriele; Fabiani, Monica; Corballis, Paul M.; Hood, Donald C.; Goodman-Wood, Marsha Ruth; Hirsch, Joy; Kim, Karl; Friedman, David; Gratton, Enrico

doi:10.1006/nimg.1997.0298

Cited by 113 publications

(88 citation statements)

References 32 publications

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“…Near-infrared spectroscopy is able to measure hemodynamic, metabolic Heekeren et al, 1999), and fast neuronal responses to brain activation Gratton et al, 1997;Steinbrink et al, 2000;Wolf et al, 2002) with inexpensive and portable instrumentation. These capabilities are making NIRS, in its present technological state, an important tool in cognition and the neurosciences.…”

Section: Discussionmentioning

confidence: 99%

Diffuse optical imaging of brain activation: approaches to optimizing image sensitivity, resolution, and accuracy

2004

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Near-infrared spectroscopy (NIRS) and diffuse optical imaging (DOI) are finding widespread application in the study of human brain activation, motivating further application-specific development of the technology. NIRS and DOI offer the potential to quantify changes in deoxyhemoglobin (HbR) and total hemoglobin (HbT) concentration, thus enabling distinction of oxygen consumption and blood flow changes during brain activation. While the techniques implemented presently provide important results for cognition and the neurosciences through their relative measures of HbR and HbT concentrations, there is much to be done to improve sensitivity, accuracy, and resolution. In this paper, we review the advances currently being made and issues to consider for improving optical image quality. These include the optimal selection of wavelengths to minimize random and systematic error propagation in the calculation of the hemoglobin concentrations, the filtering of systemic physiological signal clutter to improve sensitivity to the hemodynamic response to brain activation, the implementation of overlapping measurements to improve image spatial resolution and uniformity, and the utilization of spatial prior information from structural and functional MRI to reduce DOI partial volume error and improve image quantitative accuracy. D 2004 Elsevier Inc. All rights reserved.

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Section: Discussionmentioning

confidence: 99%

Diffuse optical imaging of brain activation: approaches to optimizing image sensitivity, resolution, and accuracy

2004

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“…Photon delay increases (by a few picoseconds) when photons cross areas of the cortex that are active (for a review, see Fabiani, G. Gratton, & Corballis, 1996) with respect to the same areas when they are inactive. This technique has a high temporal resolution, comparable to that of ERPs, and a good spatial specificity, being able to localize cortical activity to within a few millimeters from corresponding fMRI recordings (Fabiani et aI., 1996;G. Gratton et al, 1997).…”

Section: Example 2 Bootstrap Analysis Of Peaks Of the Event-related Omentioning

confidence: 99%

Bootstrap assessment of the reliability of maxima in surface maps of brain activity of individual subjects derived with electrophysiological and optical methods

Fabiani

Gratton

Corballis

et al. 1998

Behavior Research Methods, Instruments, & Computers

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Surface maps of brain activity can be obtained with electrophysiological and optical recordings. However, there are no established methods for determining the reliability of maps of brain activity across subject groups or across tasks within the same subject. In this paper, we use bootstrapping to establish the reliability of the locations of maxima in maps of surface brain activity of individual subjects obtained with ERP and optical (EROS) recordings and report sample analyses for two data sets. Bootstrapping is a nonparametric method for estimating statistical accuracy from the data in a single sample. The distribution of the statistic of interest is estimated by constructing "bootstrap samples" from a pool of all available cases (with replacement). Many "bootstrap replications" are obtained by calculating the statistic ofinterestfor each sample. In the case of brain activity,many (e.g., 10,000)amplitude distributions can be derived from the data of an individual subject. Frequency counts are then computed for each recording location to establish how many times that location corresponds to a maximum. The value obtained in this fashion represents an estimate of the reliability of the observation.The last decade has seen an enormous increase in the attention that is paid to the relative contributions of various areas ofthe brain to perception, cognition, and movement planning and execution. This has been accompanied by the development and/or increased use of several noninvasive brain imaging techniques, such as PET, fMRI, and, more recently, transcranial optical imaging (Toga & Mazziotta, 1996). In electrophysiology, thanks also to electronic and computational advances, this emphasis has corresponded to a large increase in the number of scalp locations used to record event-related brain potentials (ERPs) and the magnetoencephalogram (MEG).When ERP data are collected from dense electrode arrays, surface maps of the scalp distribution of potentials can be generated (e.g., Duffy, 1982;Gevins, 1996). One ofthe main uses ofthese maps is to examine possible dif-

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“…It is a well-known phenomenon that the neuronal sources related to the early VEP components in response to the pattern-onset/ reversal visual stimulation correspond well to the activations in the human primary visual cortex (striate cortex or V1) acquired from fMRI (Di Russo et al, 2001;. Many studies have been performed to reveal the discrepancy between the fMRI loci at V1 and EEG or MEG source locations estimated from either dipole models (Gratoon et al, 1997;Roberts et al, 2000) or distributed source models (Moradi et al, 2003), and a large variation ranging from 5 mm to several cm has been observed in the previous studies.…”

Section: Introductionmentioning

confidence: 99%

Spatial resolution of EEG cortical source imaging revealed by localization of retinotopic organization in human primary visual cortex

Gururajan

Zhang

et al. 2007

Journal of Neuroscience Methods

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The aim of the present study is to investigate the spatial resolution of electroencephalography (EEG) cortical source imaging by localizing the retinotopic organization in the human primary visual cortex (V1). Retinotopic characteristics in V1 obtained from functional magnetic resonance imaging (fMRI) study were used as reference to assess the spatial resolution of EEG since fMRI can discriminate small changes in activation in visual field. It is well-known that the activation of the early C1 component in the visual evoked potential (VEP) elicited by pattern onset stimuli coincides well with the activation in the striate cortex localized by fMRI. In the present experiments, we moved small circular checkerboard stimuli along horizontal meridian and compared the activations localized by EEG cortical source imaging with those from fMRI. Both fMRI and EEG cortical source imaging identified spatially correlated activity within V1 in each subject studied. The mean location error, between the fMRI-determined activation centers in V1 and the EEG source imaging activation peak estimated at equivalent C1 components (peak latency: 74.8 ± 10.6 ms), was 7 mm (25% and 75% percentiles are 6.45 mm and 8.4 mm, respectively), which is less than the change in fMRI activation map by a 3° visual field change (7.8 mm). Moreover, the source estimates at the earliest major VEP component showed statistically good correlation with those obtained by fMRI. The present results suggest that the spatial resolution of the EEG cortical source imaging is can correctly discriminate cortical activation changes in V1 corresponding to less than 3° visual field changes.

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Fast and Localized Event-Related Optical Signals (EROS) in the Human Occipital Cortex: Comparisons with the Visual Evoked Potential and fMRI

Cited by 113 publications

References 32 publications

Diffuse optical imaging of brain activation: approaches to optimizing image sensitivity, resolution, and accuracy

Diffuse optical imaging of brain activation: approaches to optimizing image sensitivity, resolution, and accuracy

Bootstrap assessment of the reliability of maxima in surface maps of brain activity of individual subjects derived with electrophysiological and optical methods

Spatial resolution of EEG cortical source imaging revealed by localization of retinotopic organization in human primary visual cortex

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