Constraining the general linear model for sensible hemodynamic response function waveforms

Çiftçi, Koray; Sankur, B.; Kahya, Yasemin P.; Akin, Ata

doi:10.1007/s11517-008-0347-6

Cited by 19 publications

(23 citation statements)

References 30 publications

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“…The use of a model-based fNIRI analysis approach by means of the general linear model (GLM) methodology (Bullmore et al, 1996;Friston et al, 1995;Worsley and Friston, 1995) was reported by several authors (e.g. Boas et al, 2003;Çiftçi et al, 2008;Fekete et al, 2011;Hu et al, 2010;Imai et al, 2012;Koh et al, 2007;Moriai-Izawa et al, 2012;Plichta et al, 2007a,b;Schroeter et al, 2004;Tsuzuki et al, 2012;Ye et al, 2009). GLM is a statistical linear model explaining data as a linear combination of an explanatory variable plus an error term.…”

Section: Multivariate Methods Of Typementioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,523

1,394

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This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. Contents

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Section: Multivariate Methods Of Typementioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,523

1,394

View full text Add to dashboard Cite

show abstract

“…A stimulus will cause an increase in HbO [4], thus making the signal to rise. If there is no further stimulation, this response will return to the baseline.…”

Section: Regression Model and Statistical Analysismentioning

confidence: 99%

“…Additionally, it is necessary to test whether m 2 of the HbO has returned to near the baseline. And then, to determine whether the obtained HbO was actually caused by the provided stimulus or not, m 1 is computed, see [4,27,32]. If m 1 in a channel is less than or equal to zero, the channel is concluded inactive and is discarded.…”

Section: Regression Model and Statistical Analysismentioning

confidence: 99%

“…The HR usually has been predicted by convolving the canonical HR function in fMRI with an experimental paradigm. The predicted HR and its derivatives have been utilized to establish the design matrix in the general linear model (GLM) [1,2,4], where the associated coefficients indicate the activity strengths of the signals [5]. Additionally, the blood-oxygen-leveldependent HR has been modeled as a balloon model [6,7], which was proved to be sufficient to account for nonlinearities in the event-related response [7].…”

Section: Introductionmentioning

confidence: 99%

“…fNIRS determines the concentration changes of oxy-hemoglobin (HbO) and HbR in tissues by measuring lightabsorption variations at multi-wavelengths [16]. However, in most works related to GLM [4,10,17,18], the canonical HR function was borrowed from the fMRI literature [19]. Recently, a state space model has been utilized to reconstruct the HR to an impulse stimulus from the motor cortex prompted by right index-finger tapping, the model parameters having been estimated by the recursive least-square (RLS) method [20].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

State-space models of impulse hemodynamic responses over motor, somatosensory, and visual cortices

Hong¹,

Nguyen²

2014

Biomed. Opt. Express

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Abstract:The paper presents state space models of the hemodynamic response (HR) of fNIRS to an impulse stimulus in three brain regions: motor cortex (MC), somatosensory cortex (SC), and visual cortex (VC). Nineteen healthy subjects were examined. For each cortex, three impulse HRs experimentally obtained were averaged. The averaged signal was converted to a state space equation by using the subspace method. The activation peak and the undershoot peak of the oxy-hemoglobin (HbO) in MC are noticeably higher than those in SC and VC. The time-to-peaks of the HbO in three brain regions are almost the same (about 6.76 76 ± 0.2 s). The time to undershoot peak in VC is the largest among three. The HbO decreases in the early stage (~0.46 s) in MC and VC, but it is not so in SC. These findings were well described with the developed state space equations. Another advantage of the proposed method is its easy applicability in generating the expected HR to arbitrary stimuli in an online (or real-time) imaging. Experimental results are demonstrated.

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The optimal linear transformation-based fMRI feature space analysis

Sun

Morris

Babyn

2009

Med Biol Eng Comput

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This paper proposes a method of extending the optimal linear transformation (OLT), an image analysis technique of feature space, from magnetic resonance imaging (MRI) to functional magnetic resonance imaging (fMRI) so as to improve the activation detection performance over conventional approaches of fMRI analysis. The method was: (1) ideal hemodynamic responses for different stimuli were generated by convolving the theoretical hemodynamic response model with the stimulus timing, (2) considering the ideal hemodynamic responses as hypothetical signature vectors for different activity patterns of interest, OLT was used to extract the features of fMRI data. The resultant feature space had particular geometric clustering properties. It was then classified into different groups, each pertaining to an activity pattern of interest; the applied signature vector for each group was obtained by averaging, (3) using the applied signature vectors, OLT was applied again to generate fMRI composite images with high SNRs for the desired activity patterns. Simulations and a blocked fMRI experiment were employed to validate the proposed method. The simulation and the experiment results indicated the proposed method was capable of improving some conventional methods to be more sensitive to activations, having strong contrast between activations and inactivations, and being more valid for complex activity patterns.

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Constraining the general linear model for sensible hemodynamic response function waveforms

Cited by 19 publications

References 30 publications

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

State-space models of impulse hemodynamic responses over motor, somatosensory, and visual cortices

The optimal linear transformation-based fMRI feature space analysis

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