Ragu: a free tool for the analysis of EEG and MEG event-related scalp field data using global randomization statistics
Reads0
Chats0
TLDR
The aim of Ragu is to maximize statistical power while minimizing the need for a-priori choices of models and parameters (like inverse models or sensors of interest) that interact with and bias statistics.Abstract:
We present a program (Ragu; Randomization Graphical User interface) for statistical analyses of multichannel event-related EEG and MEG experiments. Based on measures of scalp field differences including all sensors, and using powerful, assumption-free randomization statistics, the program yields robust, physiologically meaningful conclusions based on the entire, untransformed, and unbiased set of measurements. Ragu accommodates up to two within-subject factors and one between-subject factor with multiple levels each. Significance is computed as function of time and can be controlled for type II errors with overall analyses. Results are displayed in an intuitive visual interface that allows further exploration of the findings. A sample analysis of an ERP experiment illustrates the different possibilities offered by Ragu. The aim of Ragu is tomaximize statistical power while minimizing the need for a-priori choices of models and parameters (like inverse models or sensors of interest) that interact with and bias statistics.read more
Citations
More filters
Journal ArticleDOI
Towards the utilization of EEG as a brain imaging tool
TL;DR: It is shown that many cognitive and clinical EEG studies use the EEG still in its traditional way and analyze grapho-elements at certain electrodes and latencies, which is not only dangerous because it leads to misinterpretations, but it is also largely ignoring the spatial aspects of the signals.
Journal ArticleDOI
Microstates in resting-state EEG: Current status and future directions
TL;DR: It is suggested that EEG microstates represent a promising neurophysiological tool for understanding and assessing brain network dynamics on a millisecond timescale in health and disease.
Journal ArticleDOI
EEG microstates associated with salience and frontoparietal networks in frontotemporal dementia, schizophrenia and Alzheimer's disease.
Keiichiro Nishida,Keiichiro Nishida,Yosuke Morishima,Masafumi Yoshimura,Toshiaki Isotani,Satoshi Irisawa,Kay Jann,Thomas Dierks,Werner Strik,Toshihiko Kinoshita,Thomas Koenig +10 more
TL;DR: The duration and sequence of EEG microstates reflect specific aberrations of frontal lobe functions in FTD and schizophrenia, highlighting the importance of subsecond brain dynamics for understanding of psychiatric disorders.
Journal ArticleDOI
TDCS increases cortical excitability: direct evidence from TMS-EEG.
Leonor J. Romero Lauro,Mario Rosanova,Giulia Mattavelli,Silvia Convento,Alberto Pisoni,Alexander Opitz,Nadia Bolognini,Giuseppe Vallar +7 more
TL;DR: A diffuse rise of cortical excitability occurred, both during and after active tDCS, which highlights the spreading of the effects of anodal tDCS over remote cortical regions of stimulated and contralateral hemispheres.
Journal ArticleDOI
The functional significance of EEG microstates--Associations with modalities of thinking
Patricia Milz,Pascal L. Faber,Dietrich Lehmann,Thomas Koenig,Kieko Kochi,Roberto D. Pascual-Marqui +5 more
TL;DR: The results point to the possibility that the EEG micro state classes may represent the head-surface measured activity of intra-cortical sources primarily exhibiting inhibitory functions, and suggest that a finely-tuned interplay between all four EEG microstate classes is necessary for the continuous formation of visual and verbal thoughts.
References
More filters
Journal ArticleDOI
Nonparametric permutation tests for functional neuroimaging: A primer with examples
TL;DR: The standard nonparametric randomization and permutation testing ideas are developed at an accessible level, using practical examples from functional neuroimaging, and the extensions for multiple comparisons described.
Book
Randomization, Bootstrap and Monte Carlo Methods in Biology
TL;DR: The idea of a randomization test has been explored in the context of data analysis for a long time as mentioned in this paper, and it has been applied in a variety of applications in biology, such as single species ecology and community ecology.
Journal ArticleDOI
Reading senseless sentences: brain potentials reflect semantic incongruity
Marta Kutas,Steven A. Hillyard +1 more
TL;DR: In a sentence reading task, words that occurred out of context were associated with specific types of event-related brain potentials that elicited a late negative wave (N400).
Journal ArticleDOI
Reference-free identification of components of checkerboard-evoked multichannel potential fields
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.
Journal ArticleDOI
EEG and MEG: forward solutions for inverse methods
TL;DR: Novel reformulations of the basic EEG and MEG kernels that dispel the myth that EEG is inherently more complicated to calculate than MEG are presented and evidence that improvements over currently published BEM methods can be realized using alternative error-weighting methods is presented.
Related Papers (5)
Topographic ERP Analyses: A Step-by-Step Tutorial Review
Reference-free identification of components of checkerboard-evoked multichannel potential fields
EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis.
Arnaud Delorme,Scott Makeig +1 more