A Study on Asymmetry of Spatial Visual Field by Analysis of the fMRI BOLD Response

Chen, Huafu; Yao, Dezhong; Liu, Zuxiang

doi:10.1023/b:brat.0000047335.00110.6a

Cited by 23 publications

(18 citation statements)

References 42 publications

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“…4(B), blue asterisks], consistent with the advantage of the lower visual field found in previous MEG studies using high contrast checkerboards [Portin et al, 1999], vertical gratings [Tzelepi et al, 2001], and face stimuli [Liu and Ioannides, 2006], as well as an fMRI study which also used checkerboard stimuli [Chen et al, 2004]. After adjusting spatial luminance uniformity (see Materials and Methods), we confirmed the lower visual field advantage and extended upon the earlier findings for motion stimuli.…”

Section: Advantage Of the Lower Visual Fieldsupporting

confidence: 89%

Stimulus‐contrast‐induced biases in activation order reveal interaction between V1/V2 and human MT+

Maruyama

Palomo

Ioannides

2007

Human Brain Mapping

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Abstract:The luminance contrast of a visual stimulus is known to modulate the response properties of areas V1 and the human MT complex (hMT1), but has not been shown to modulate interactions between these two areas. We examined the direction of information transfer between V1/V2 and hMT1 at different stimulus contrasts by measuring magnetoencephalographic (MEG) responses to moving and stationary stimuli presented centrally or peripherally. To determine the direction of information flow, the different response latencies among stimuli and hemispheres in V1/V2 was compared with those of hMT1. At high contrast, responses to stimulus motion and position began in V1/V2, and were followed in hMT1 with a delay between 34 and 55 ms. However, at low contrast, lateralized responses in hMT1 came first, with those in V1/V2 lagging with a delay of 27 ms. Also, at high contrast, stationary stimuli produced greater responses than motion stimuli in V1/V2, while the reverse was true in hMT1, whose response lagged behind the initial response in V1/V2. The same activation order was found using Mutual Information Analysis of the response variances for each condition. Here, the response variances in hMT1 mimicked and trailed those of V1/V2 at high contrast, whereas the reverse was true at low contrast. Such consistent interactions found using two different methodologies strongly supports a processing link between these two areas. The results also suggest that feedback from hMT1 for low-contrast stimuli compensates for unresolved processing in V1/V2 when the input of a visual image is weak.

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Section: Advantage Of the Lower Visual Fieldsupporting

confidence: 89%

Stimulus‐contrast‐induced biases in activation order reveal interaction between V1/V2 and human MT+

Maruyama

Palomo

Ioannides

2007

Human Brain Mapping

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“…11 show that the dynamic waveforms of the BOLD signals in different occipital lobe regions are distinctly different from each other, consistent with our prior ICA and model studies [27]- [29]. If comparing with the stimulus pattern, signal 1 in Fig.…”

Section: A the Difference Of The Dynamic Responsessupporting

confidence: 83%

“…In this blank trial, only the center fixation cross (0.8 ) was displayed. Subjects were required to concentrate on the fixation cross and press a button upon detection of an infrequent brightness change of the fixation cross [26], [27].…”

Section: Experimental Paradigmmentioning

confidence: 99%

An Integrated Neighborhood Correlation and Hierarchical Clustering Approach of Functional MRI

Chen

Yuan

Yao

et al. 2006

IEEE Trans. Biomed. Eng.

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Abstract-Clustering analysis is a promising data-driven method for the analysis of functional magnetic resonance imaging (fMRI) time series, however, the huge computation load makes it difficult for practical use. In this paper, neighborhood correlation (NC) and hierarchical clustering (HC) methods are integrated as a new approach where fMRI data are processed first by NC to get a preliminary image of brain activations, and then by HC to remove some noises. In HC, to better use spatial and temporal information in fMRI data, a new spatio-temporal measure is introduced. A simulation study and an application to visual fMRI data show that the brain activations can be effectively detected and that different response patterns can be discriminated. These results suggest that the proposed new integrated approach could be useful in detecting weak fMRI signals.

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“…Several procedures have been investigated. Poisson (18), gamma (19,(36)(37)(38), and Gaussian (20,21,39) functions have been implemented to model the HRF. Currently, gamma and Gaussian functions are still used often in models.…”

Section: Discussionmentioning

confidence: 99%

“…Fitting of BOLD responses is essential for quantification, and many studies have proposed procedures for HRF estimation and modeling, including Poisson functions (18), gamma functions (19), and Gaussian functions (20,21). In 2007, Lindquist and Wager (22) developed an algorithm comprising three inverse logit (IL) functions to fit HRFs, each corresponding to one of the HRF phases specified above.…”

mentioning

confidence: 99%

Quantifying hemodynamic refractory bold effects in normal subjects at the single‐subject level using an inverse logit fitting procedure

Descamps

Vandemaele

Reyngoudt

et al. 2011

Magnetic Resonance Imaging

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Purpose: To evaluate whether hemodynamic refractory effects provoked by repeated visual stimulation can be detected and quantified at the single-subject level using a recently described hemodynamic response function (HRF) fitting algorithm. Materials and Methods:Hemodynamic refractory effects were induced with an easily applicable functional MRI (fMRI) paradigm. A fitting method with inverse logit (IL) functions was applied to quantify net HRFs at the singlesubject level with three interstimulus intervals (ISI; 1, 2, and 6 s). The model yielded amplitude, latencies, and width for each HRF.Results: HRF fitting was possible in 44 of 51 healthy volunteers, with excellent goodness-of-fit (R 2 ¼ 0.9745 6 0.0241). Refractory effects were most pronounced for the 1-s ISI (P < 0.001) and had nearly disappeared for the 6-s ISI.Conclusion: Quantifying refractory effects in individuals was possible in 86.3% of normal subjects using the IL fitting algorithm. This setup may be suitable to explore such effects in individual patients.

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A Study on Asymmetry of Spatial Visual Field by Analysis of the fMRI BOLD Response

Cited by 23 publications

References 42 publications

Stimulus‐contrast‐induced biases in activation order reveal interaction between V1/V2 and human MT+

Stimulus‐contrast‐induced biases in activation order reveal interaction between V1/V2 and human MT+

An Integrated Neighborhood Correlation and Hierarchical Clustering Approach of Functional MRI

Quantifying hemodynamic refractory bold effects in normal subjects at the single‐subject level using an inverse logit fitting procedure

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