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Functional near-infrared spectroscopy (fNIRS) has now become widely accepted as a common functional imaging modality. In order for fNIRS to achieve genuine neuroimaging citizenship, it would ideally be equipped with functional and structural image analyses. However, fNIRS measures cortical activities from the head surface without anatomical information of the object being measured. In this review article, we will present a methodological overview of spatial registration of fNIRS data to overcome this technical drawback of fNIRS. We first introduce and explore the use of standard stereotaxic space and anatomical labeling. Second, we explain different ways of describing scalp landmarks using 10-20 based systems. Third, we describe the simplest case of fNIRS data co-registration to a subject's own MRI. Fourth, we extend the concept to fNIRS data registration of group data. Fifth, we describe probabilistic registration methods, which use a reference-MRI database instead of a subject's own MRIs, and thus enable MRI-free registration for standalone fNIRS data. Sixth, we further extend the concept of probabilistic registration to three-dimensional image reconstruction in diffuse optical tomography. Seventh, we describe a 3D-digitizer-free method for the virtual registration of fNIRS data. Eighth, we provide practical guidance on how these techniques are implemented in software. Finally, we provide information on current resources and limitations for spatial registration of child and infant data. Through these technical descriptions, we stress the importance of presenting fNIRS data on a common platform to facilitate both intra- and inter-modal data sharing among the neuroimaging community., (© 2013 Elsevier Inc. All rights reserved.)

We describe the validation of an anatomical brain atlas approach to the analysis of diffuse optical tomography (DOT). Using MRI data from 32 subjects, we compare the diffuse optical images of simulated cortical activation reconstructed using a registered atlas with those obtained using a subject's true anatomy. The error in localization of the simulated cortical activations when using a registered atlas is due to a combination of imperfect registration, anatomical differences between atlas and subject anatomies and the localization error associated with diffuse optical image reconstruction. When using a subject-specific MRI, any localization error is due to diffuse optical image reconstruction only. In this study we determine that using a registered anatomical brain atlas results in an average localization error of approximately 18 mm in Euclidean space. The corresponding error when the subject's own MRI is employed is 9.1 mm. In general, the cost of using atlas-guided DOT in place of subject-specific MRI-guided DOT is a doubling of the localization error. Our results show that despite this increase in error, reasonable anatomical localization is achievable even in cases where the subject-specific anatomy is unavailable., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We aimed to explore the interactive effects of the accessibility of information and the degree of carbon footprint score on consumers' value judgments of food products. Participants (n=151, undergraduate students in Japan) rated their maximum willingness to pay (WTP) for four food products varying in information accessibility (active-search or read-only conditions) and in carbon footprint values (low, middle, high, or non-display) provided. We also assessed further effects of information accessibly and carbon footprint value on other product attributes utilizing the subjective estimation of taste, quality, healthiness, and environmental friendliness. Results of the experiment demonstrated an interactive effect of information accessibility and the degree of carbon emission on consumer valuation of carbon footprint-labeled food. The carbon footprint value had a stronger impact on participants' WTP in the active-search condition than in the read-only condition. Similar to WTP, the results of the subjective ratings for product qualities also exhibited an interactive effect of the two factors on the rating of environmental friendliness for products. These results imply that the perceived environmental friendliness inferable from a carbon footprint label contributes to creating value for a food product.

A growing number of human studies have reported the beneficial influences of acute as well as chronic exercise on cognitive functions. However, neuroimaging investigations into the neural substrates of the effects of acute exercise have yet to be performed. Using multichannel functional near-infrared spectroscopy (fNIRS), we sought cortical activation related to changes in the Stroop interference test, elicited by an acute bout of moderate exercise, in healthy volunteers (N=20). The compactness and portability of fNIRS allowed on-site cortical examination in a laboratory with a cycle ergometer, enabling strict control of the exercise intensity of each subject by assessing their peak oxygen intake (VO2peak). We defined moderate exercise intensity as 50% of a subject's peak oxygen uptake (50%VO2peak). An acute bout of moderate exercise caused significant improvement of cognitive performance reflecting Stroop interference as measured by reaction time. Consistent with previous functional neuroimaging studies, we detected brain activation due to Stroop interference (incongruent minus neutral) in the lateral prefrontal cortices in both hemispheres. This Stroop-interference-related activation was significantly enhanced in the left dorsolateral prefrontal cortex due to the acute bout of moderate exercise. The enhanced activation significantly coincided with the improved cognitive performance. This suggests that the left dorsolateral prefrontal cortex is likely the neural substrate for the improved Stroop performance elicited by an acute bout of moderate exercise. fNIRS, which allows physiological monitoring and functional neuroimaging to be combined, proved to be an effective tool for examining the cognitive effects of exercise., (2009 Elsevier Inc. All rights reserved.)

We investigated the effect that the parameters of luminance distribution in fresh food have on our visual perception of its freshness. We took pictures of the degradation over 32 h in freshness of a cabbage. We used original images, which were patches of the pictures taken at different sampling hours, and artificially generated pictures, called "matched images," created by fitting the luminance histogram shape of the original image (taken at the 1st hour) to those at various freshness stages using a luminance histogram-matching algorithm. Nine participants rated the perceived freshness of the original and the matched images on a scale of degradation. As a result, we found that the participants could quantitatively estimate the degradation in freshness of the cabbage simply by looking at the presented images. Some parameters of the luminance histograms monotonically change with decreasing freshness, indicating that the freshness of cabbage can be estimated using these parameters. However, the freshness ratings for the matched images after the 8th hour of degradation had lower modification than those for the respective original images. These results suggest that the luminance distribution in the vegetable texture partly contributes to visual freshness perception but other variables, such as spatial patterns, might also be important for estimating visual freshness., (Copyright 2010 Elsevier Ltd. All rights reserved.)

We describe a neuroimaging protocol that utilizes an anatomical atlas of the human head to guide diffuse optical tomography of human brain activation. The protocol is demonstrated by imaging the hemodynamic response to median-nerve stimulation in three healthy subjects, and comparing the images obtained using a head atlas with the images obtained using the subject-specific head anatomy. The results indicate that using the head atlas anatomy it is possible to reconstruct the location of the brain activation to the expected gyrus of the brain, in agreement with the results obtained with the subject-specific head anatomy. The benefits of this novel method derive from eliminating the need for subject-specific head anatomy and thus obviating the need for a subject-specific MRI to improve the anatomical interpretation of diffuse optical tomography images of brain activation.

We explored the feasibility of introducing implicit attitude measures for the study of food-related stereotypes by assessing gender-based food stereotypes among young Japanese using a semantic priming paradigm. Thirty-seven Japanese university students were asked to judge if a given forename was male or female immediately after the presentation of a food-name prime stimulus. The participants required significantly less time to verify the gender of forenames when the stereotyped gender of the food and the gender of forename were congruent than when they were incongruent. We demonstrate that a semantic priming paradigm is capable of uncovering implicit gender-based food stereotypes.

Food purchasing decisions of consumers are influenced by information on food labels such as origin and nutritional value of the food product. Thus, we aimed to elucidate the impact of the amount and accessibility of information on consumers' value judgment of food products. Participants (n=120, Japanese university students) rated their maximum willingness to pay (WTP) for three food products varying in information accessibility (active-search or read-only conditions) and in the amount of information (small, medium, or large) provided. We will demonstrate that a consumer's WTP depends on the interaction between these two factors. In the active-search condition, food products with a large amount of information were valued significantly higher than those with less information. However, in the read-only condition, food products with a medium amount of information were valued significantly higher than those with little information, and there was no significant difference between conditions with large and small amounts of information. To conclude, a larger amount of information led to a higher value only when participants searched for the information actively, whereas a moderate amount of information did the best when participants are only allowed to read the information.

We investigated the effect of the appearance of cut food on visual mass estimation. In this experiment, we manipulated the shape (e.g., a block, fine strips, or small cubes) of food samples of various masses, and presented them on a CRT display as stimuli. Eleven subjects participated in tasks to choose the picture of the food sample which they felt indicated a target mass. We used raw carrots and surimi (ground fish) gel as hard and soft samples, respectively. The results clearly confirm an existence of an illusion, and this indicates that the appearance of food interferes with visual mass estimation. Specifically, participants often overestimated the mass of finely cut food, especially fine strips, whereas they could accurately estimate the mass of block samples, regardless of the physical characteristics of the foods. The overestimation of the mass of cut food increased with the food's actual mass, and was particularly obvious with increases of apparent volume when cut into fine strips. These results suggest that the apparent volume of a food sample effects the visual estimation of its mass. Hence we can conclude that there are illusions associated with the visual presentation of food that may influence various food impressions, including satisfaction and eating behaviour.

With the advent of multi-channel EEG hardware systems and the concurrent development of topographic and tomographic signal source localization methods, the international 10/20 system, a standard system for electrode positioning with 21 electrodes, was extended to higher density electrode settings such as 10/10 and 10/5 systems, allowing more than 300 electrode positions. However, their effectiveness as relative head-surface-based positioning systems has not been examined. We previously developed a virtual 10/20 measurement algorithm that can analyze any structural MR head and brain image. Extending this method to the virtual 10/10 and 10/5 measurement algorithms, we analyzed the MR images of 17 healthy subjects. The acquired scalp positions of the 10/10 and 10/5 systems were normalized to the Montreal Neurological Institute (MNI) stereotactic coordinates and their spatial variability was assessed. We described and examined the effects of spatial variability due to the selection of positioning systems and landmark placement strategies. As long as a detailed rule for a particular system was provided, it yielded precise landmark positions on the scalp. Moreover, we evaluated the effective spatial resolution of 329 scalp landmark positions of the 10/5 system for multi-subject studies. As long as a detailed rule for landmark setting was provided, 241 scalp positions could be set effectively when there was no overlapping of two neighboring positions. Importantly, 10/10 positions could be well separated on a scalp without overlapping. This study presents a referential framework for establishing the effective spatial resolutions of 10/20, 10/10, and 10/5 systems as relative head-surface-based positioning systems.

The registration of functional brain data to common stereotaxic brain space facilitates data sharing and integration across different subjects, studies, and even imaging modalities. Thus, we previously described a method for the probabilistic registration of functional near-infrared spectroscopy (fNIRS) data onto Montreal Neurological Institute (MNI) coordinate space that can be used even when magnetic resonance images of the subjects are not available. This method, however, requires the careful measurement of scalp landmarks and fNIRS optode positions using a 3D-digitizer. Here we present a novel registration method, based on simulations in place of physical measurements for optode positioning. First, we constructed a holder deformation algorithm and examined its validity by comparing virtual and actual deformation of holders on spherical phantoms and real head surfaces. The discrepancies were negligible. Next, we registered virtual holders on synthetic heads and brains that represent size and shape variations among the population. The registered positions were normalized to MNI space. By repeating this process across synthetic heads and brains, we statistically estimated the most probable MNI coordinate values, and clarified errors, which were in the order of several millimeters across the scalp, associated with this estimation. In essence, the current method allowed the spatial registration of completely stand-alone fNIRS data onto MNI space without the use of supplementary measurements. This method will not only provide a practical solution to the spatial registration issues in fNIRS studies, but will also enhance cross-modal communications within the neuroimaging community.