Comparing spectra and coherences for groups of unequal size

Bokil, H. S., Purpura, K., Schoffelen, J. M., Thomson, D., Mitra, P. P. (January 2007) Comparing spectra and coherences for groups of unequal size. J Neurosci Methods, 159 (2). pp. 337-45. ISSN 0165-0270 (Print)

DOI: 10.1016/j.jneumeth.2006.07.011


Spectra and coherences are standard measures of association within and between time series. These measures have several advantages over their time-domain counterparts, not the least of which is the ability to derive and estimate confidence intervals. However, comparing spectra and coherences between two groups of observation is a problem that has not received much attention. This problem is important in neuroscience since it is often of great interest to determine whether the estimates differ between distinct experimental/behavioral conditions. Here we propose one approach to this problem. Based on the known distributional properties of spectral and coherence estimates, we derive a test for equality of two spectral or coherence estimates. The test is applicable to unequal sample sizes. We also derive jackknifed estimates of the variance of the proposed test statistic. We suggest that comparing the estimates obtained from the jackknife procedure with the theoretical estimates provides a robust means of determining whether the data in question shows non-Gaussian or non-stationary behavior. Finally, we present applications of the method to simulated and real data.

Item Type: Paper
Uncontrolled Keywords: Computer Simulation Electromyography/ methods Frontal Lobe/physiology Humans Magnetocardiography/ methods Models, Neurological Muscle, Skeletal/innervation/physiology Parietal Lobe/physiology Software Stochastic Processes
Subjects: bioinformatics > genomics and proteomics > analysis and processing
bioinformatics > quantitative biology
bioinformatics > genomics and proteomics > computers > computer software
organs, tissues, organelles, cell types and functions > tissues types and functions > frontal lobe
CSHL Authors:
Communities: CSHL labs > Mitra lab
Depositing User: CSHL Librarian
Date: 30 January 2007
Date Deposited: 01 Dec 2011 21:04
Last Modified: 06 Feb 2017 16:18
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