title: Towards a standard analysis for functional near-infrared imaging.
abstract: Functional near-infrared spectroscopy (fNIRS) allows the ability to monitor brain activation by measuring changes in the concentration of oxy- and deoxy-hemoglobin. Until now no standardized approach for fNIRS data analysis has been established, although this has to be regarded as a precondition for future application. Hence, we applied the well-established general linear model to optical imaging data. Further, fNIRS data were analyzed in the frequency domain. Two visual tasks were investigated with optical imaging: a checkerboard paradigm supposed to activate the primary and secondary visual cortex, and a paradigm consisting of moving colored stimuli (rotating 'L's) additionally involving the motion area V5. Analysis with the general linear model detected the activation focus in the primary and secondary visual cortex during the first paradigm. For the second paradigm, a second laterally localized activated brain region was found, most likely representing V5. Spatially resolved spectral analysis confirmed the results by showing maxima of power spectral density and coherence in the same respective brain regions. Moreover, it demonstrated a delay of the hemodynamic response in the motion area. In summary, the present study suggests that the general linear model and spatially resolved spectral analysis can be used as standard statistical approaches for optical imaging data, particularly because they are almost independent of the assumed differential path length factors.
authors.affiliation: Day Clinic of Cognitive Neurology, University of Leipzig, 04103, Leipzig, Germany. schroet@cns.mpg.de
authors.forename: Matthias L
authors.initials: ML
authors.lastname: Schroeter
authors.forename: Markus M
authors.initials: MM
authors.lastname: Bücheler
authors.forename: Karsten
authors.initials: K
authors.lastname: Müller
authors.forename: Kâmil
authors.initials: K
authors.lastname: Uludağ
authors.forename: Hellmuth
authors.initials: H
authors.lastname: Obrig
authors.forename: Gabriele
authors.initials: G
authors.lastname: Lohmann
authors.forename: Marc
authors.initials: M
authors.lastname: Tittgemeyer
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: D Yves
authors.initials: DY
authors.lastname: von Cramon
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003118:Color Perception / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005583:Fourier Analysis; D006439:Hemodynamics / Q000502:physiology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000592:standards*; D021621:Imaging, Three-Dimensional / Q000592:standards*; D016014:Linear Models; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D010108:Oxyhemoglobins / Q000378:metabolism; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000592:standards*; D041622:Tomography, Optical / Q000592:standards*; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin