ANALYSIS OF FMRI TIME-SERIES REVISITED - AGAIN

被引:1725
作者
WORSLEY, KJ [1 ]
FRISTON, KJ [1 ]
机构
[1] HAMMERSMITH HOSP, MRC, WELLCOME DEPT COGNIT NEUROL, CYCLOTRON UNIT, LONDON W12 0HS, ENGLAND
基金
英国惠康基金;
关键词
D O I
10.1006/nimg.1995.1023
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Friston et al. (1995, NeuroImage 2: 45-53) presented a method for detecting activations in fMRI time-series based on the general linear model and a heuristic analysis of the effective degrees of freedom, In this communication we present corrected results that replace those of the previous paper and solve the same problem without recourse to heuristic arguments. Specifically we introduce a proper and unbiased estimator for the error terms and provide a more generally correct expression for the effective degrees of freedom. The previous estimates of error variance were biased and, in some instances, could have led to a 10-20% overestimate of Z values. Although the previous results are almost correct for the random regressors chosen for validation, the present theoretical results are exact for any covariate or waveform. We comment on some aspects of experimental design and data analysis, in the light of the theoretical framework discussed here. (C) 1995 Academic Press, Inc.
引用
收藏
页码:173 / 181
页数:9
相关论文
共 16 条
  • [1] Friston K., 1994, HUMAN BRAIN MAPPING, V1, P153, DOI DOI 10.1002/HBM.460010207
  • [2] Friston K. J., 1994, HUMAN BRAIN MAPPING, V1, P210
  • [3] COMPARING FUNCTIONAL (PET) IMAGES - THE ASSESSMENT OF SIGNIFICANT CHANGE
    FRISTON, KJ
    FRITH, CD
    LIDDLE, PF
    FRACKOWIAK, RSJ
    [J]. JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM, 1991, 11 (04) : 690 - 699
  • [4] CHARACTERIZING EVOKED HEMODYNAMICS WITH FMRI
    FRISTON, KJ
    FRITH, CD
    TURNER, R
    FRACKOWIAK, RSJ
    [J]. NEUROIMAGE, 1995, 2 (02) : 157 - 165
  • [5] ANALYSIS OF FMRI TIME-SERIES REVISITED
    FRISTON, KJ
    HOLMES, AP
    POLINE, JB
    GRASBY, PJ
    WILLIAMS, SCR
    FRACKOWIAK, RSJ
    TURNER, R
    [J]. NEUROIMAGE, 1995, 2 (01) : 45 - 53
  • [6] CHARACTERIZING DYNAMIC BRAIN RESPONSES WITH FMRI - A MULTIVARIATE APPROACH
    FRISTON, KJ
    FRITH, CD
    FRACKOWIAK, RSJ
    TURNER, R
    [J]. NEUROIMAGE, 1995, 2 (02) : 166 - 172
  • [7] ANALYSIS OF INDIVIDUAL BRAIN ACTIVATION MAPS USING HIERARCHICAL DESCRIPTION AND MULTISCALE DETECTION
    POLINE, JB
    MAZOYER, BM
    [J]. IEEE TRANSACTIONS ON MEDICAL IMAGING, 1994, 13 (04) : 702 - 710
  • [8] ENHANCED DETECTION IN BRAIN ACTIVATION MAPS USING A MULTIFILTERING APPROACH
    POLINE, JB
    MAZOYER, BM
    [J]. JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM, 1994, 14 (04) : 639 - 642
  • [9] AN APPROXIMATE DISTRIBUTION OF ESTIMATES OF VARIANCE COMPONENTS
    SATTERTHWAITE, FE
    [J]. BIOMETRICS BULLETIN, 1946, 2 (06): : 110 - 114
  • [10] Seber G. A. F., 1977, LINEAR REGRESSION AN