Reference-free identification of components of checkerboard-evoked multichannel potential fields
01 Jun 1980-Electroencephalography and Clinical Neurophysiology (Elsevier)-Vol. 48, Iss: 6, pp 609-621
TL;DR: A method is proposed to determine components of evoked scalp potentials, in terms of times of occurrence (latency) and location on the scalp (topography), suggesting a stable localization of the generating process in depth.
About: This article is published in Electroencephalography and Clinical Neurophysiology.The article was published on 1980-06-01. It has received 1435 citations till now. The article focuses on the topics: Evoked field.
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TL;DR: A direct comparison of the tomography results with those obtained from fitting one and two dipoles illustrates that the new method provides physiologically meaningful results while dipolar solutions fail in many situations.
2,729 citations
Cites background from "Reference-free identification of co..."
...GFP is the spatial standard deviation of the average reference potential map at each moment in time, indicating the instantaneous strength of the field (Lehmann and Skrandies, 1980)....
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TL;DR: New guidelines for recording ERPs are presented and criteria for publishing the results are presented, which allow different studies to be compared readily.
Abstract: Event-related potentials ~ERPs! recorded from the human scalp can provide important information about how the human brain normally processes information and about how this processing may go awry in neurological or psychiatric disorders. Scientists using or studying ERPs must strive to overcome the many technical problems that can occur in the recording and analysis of these potentials. The methods and the results of these ERP studies must be published in a way that allows other scientists to understand exactly what was done so that they can, if necessary, replicate the experiments. The data must then be analyzed and presented in a way that allows different studies to be compared readily. This paper presents guidelines for recording ERPs and criteria for publishing the results.
2,033 citations
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TL;DR: It is shown that modern EEG source imaging simultaneously details the temporal and spatial dimensions of brain activity, making it an important and affordable tool to study the properties of cerebral, neural networks in cognitive and clinical neurosciences.
1,600 citations
Cites background or methods from "Reference-free identification of co..."
...A simple way to compare map topographies is to calculate the so-called Global Dissimilarity (Lehmann and Skrandies, 1980)....
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...In order to circumvent this problem, the peaks of the Global Field Power (GFP, spatial root mean squared across all electrodes; Lehmann and Skrandies, 1980) are sometimes selected....
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...Global Dissimilarity ranges from values of 0 (map homogeneity) to 2 (map inversion)....
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...Interestingly, this mathematically corresponds to the calculation of the average reference of the surface potential (Lehmann and Skrandies, 1980)....
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TL;DR: In this article, an enhancement of mu rhythms in the primary hand area during visual processing or during foot movement was observed. But the hand area is not needed for visual processing, nor is it needed for preparation for foot movement.
1,030 citations
TL;DR: This tutorial review detail both the rationale for as well as the implementation of a set of analyses of surface-recorded event-related potentials (ERPs) that uses the reference-free spatial information available from high-density electrode montages to render statistical information concerning modulations in response strength, latency, and topography both between and within experimental conditions.
Abstract: In this tutorial review, we detail both the rationale for as well as the implementation of a set of analyses of surface-recorded event-related potentials (ERPs) that uses the reference-free spatial (i.e. topographic) information available from high-density electrode montages to render statistical information concerning modulations in response strength, latency, and topography both between and within experimental conditions. In these and other ways these topographic analysis methods allow the experimenter to glean additional information and neurophysiologic interpretability beyond what is available from canonical waveform analyses. In this tutorial we present the example of somatosensory evoked potentials (SEPs) in response to stimulation of each hand to illustrate these points. For each step of these analyses, we provide the reader with both a conceptual and mathematical description of how the analysis is carried out, what it yields, and how to interpret its statistical outcome. We show that these topographic analysis methods are intuitive and easy-to-use approaches that can remove much of the guesswork often confronting ERP researchers and also assist in identifying the information contained within high-density ERP datasets.
916 citations
Cites background or methods from "Reference-free identification of co..."
...[3, 27, 31, 32, 37, 38, 60, 61), though several others are also noteworthy [11, 12, 15]....
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...GFP was first introduced by Lehmann and Skrandies [32] and has since become a commonplace measure among MEG users....
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...Like GFP, DISS was first introduced by Lehmann and Skrandies [32]....
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...So, which one should be used? We advocate the use of a common average reference [32] for the following reason....
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References
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TL;DR: The waveform and topography of components of the scalp recorded somatosensory evoked poal (AEP) to click stimulation of the right ear, were determined and should aid in predicting SEP and AEP characteristics and in assessing myogenic distortion of neurogenic components.
304 citations
TL;DR: The results establish the technical feasibility of finding equivalent dipoles in the visual cortex for human visually evoked scalp potentials (VESP's), as well as the potential for the detection of multiple sources.
Abstract: A quantitative evaluation has been made of methods designed to identify the intracranial sources of scalp recorded potentials. The scheme presented models the sources as equivalent dipoles and allows for the detection of multiple sources. The head is modeled by both homogeneous and inhomogeneous spheres. The results establish the technical feasibility of finding equivalent dipoles in the visual cortex for human visually evoked scalp potentials (VESP's).
301 citations
TL;DR: It appears that the assumption of three stationary, semi-independent generators can account for the main features of alpha fields, which were recorded from the scalp of five subjects using a 48-channel system.
287 citations
"Reference-free identification of co..." refers methods or result in this paper
...Impor tant changes of location of the extreme values, and thus of the field configurations, occur within very short t ime spans, in large spatial jumps, during periods of low power of the fields, similar to the observations made on alpha fields (Lehmann 1971) and spike-wave fields (Lehmann 1975}....
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...channel recordings (Lehmann 1971, 1975). R~mond (1968) proposed a one-dimensional calculation of evoked power, using data obtained from a chain of 8 scalp electrodes....
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TL;DR: In this paper, an approach to the quantitative analysis of average evoked potential data is presented, where the average potential is assumed to be a sample from a multivariate normal distribution, and multivariate statistical techniques can be applied to test hypotheses about the similarity or difference of the potentials obtained under different conditions.
Abstract: An approach to the quantitative analysis of average evoked potential data is presented. An average evoked potential is assumed to be a sample from a multivariate normal distribution. Using this assumption, multivariate statistical techniques can be applied to test hypotheses about the similarity or difference of evoked potentials obtained under different conditions.
215 citations
01 Jan 1966
TL;DR: An approach to the quantitative analysis of average evoked potential data is presented and it is assumed to be a sample from a multivariate normal distribution that can be applied to test hypotheses about the similarity or difference of evokes obtained under different conditions.
Abstract: An approach tothequantitative analysis ofaverage evoked potential dataispresented. Anaverage evokedpotential is assumedtobea sample fromamultivariate normaldistribution. Usingthisassumption, multivariate statistical techniques canbe applied totest hypotheses about thesimilarity ordifference ofevoked potentials obtained underdifferent conditions. Tofacilitate theanalysis andtoprovide anobjective definition ofthecomponents oftheevokedpotentials, aprincipal component analysis canbeapplied tothedatamatrix transforming eachevoked potential into avector ofuncorrelated component scores. Theregion intimeoverwhicheachcomponent actscanbedetermined fromthe correlations between thecomponents identified andthetime-coordi- nates. Theapplication ofthese techniques isillustrated forstudies ofthe effect ofstimulus intensity andstimulus duration ontheevoked potential.
207 citations