Atlas‐guided volumetric diffuse optical tomography enhanced by generalized linear model analysis to image risk decision‐making responses in young adults

Abstract

Diffuse optical tomography (DOT) is a variant of functional near infrared spectroscopy and has the capability of mapping or reconstructing three dimensional (3D) hemodynamic changes due to brain activity. Common methods used in DOT image analysis to define brain activation have limitations because the selection of activation period is relatively subjective. General linear model (GLM)-based analysis can overcome this limitation. In this study, we combine the atlas-guided 3D DOT image reconstruction with GLM-based analysis (i.e., voxel-wise GLM analysis) to investigate the brain activity that is associated with risk decision-making processes. Risk decision-making is an important cognitive process and thus is an essential topic in the field of neuroscience. The Balloon Analog Risk Task (BART) is a valid experimental model and has been commonly used to assess human risk-taking actions and tendencies while facing risks. We have used the BART paradigm with a blocked design to investigate brain activations in the prefrontal and frontal cortical areas during decision-making from 37 human participants (22 males and 15 females). Voxel-wise GLM analysis was performed after a human brain atlas template and a depth compensation algorithm were combined to form atlas-guided DOT images. In this work, we wish to demonstrate the excellence of using voxel-wise GLM analysis with DOT to image and study cognitive functions in response to risk decision-making. Results have shown significant hemodynamic changes in the dorsal lateral prefrontal cortex (DLPFC) during the active-choice mode and a different activation pattern between genders; these findings correlate well with published literature in functional magnetic resonance imaging (fMRI) and fNIRS studies.

Automated voxel classification used with atlas-guided diffuse optical tomography for assessment of functional brain networks in young and older adults

“…Specifically, the bandpass filter chosen in this study was 0.02 to 0.3 Hz, as suggested by a previous study, to eliminate the physiological noise generated by heartbeat and respirations. 5 A global signal referencing approach was applied to the channel-wise fNIRS signals to further eliminate the unmodeled global physiology or structure noise. 33 Specifically, for each participant, averaging over 75-channel time sequences generated a global signal.…”

“…Our previous study 5 and many others from the literature 2,4,6 extensively introduced the atlas-DOT algorithm. We briefly describe the method as follows.…”

“…Specifically, we performed an affine transformation 34 between the standard 10-20 system landmarks in ICBM152 MNI space and the 3-D digitizer measurements of subject-specific locations. 5,31 The coordinates of projected optodes for each individual were then normalized in the standard MNI space in the ICBM 152 brain atlas. Figure 3 light sources and the blue spots represent the locations of light detectors.…”

“…[2][3][4] Atlas-DOT utilized a finite element technique with either subject-specific models 3,4 or a standard magnetic resonance imaging (MRI) brain template (such as ICBM 256) in the forward calculation. 5,6 A significant improvement of accuracy in image reconstruction and source localization has been achieved with atlas-DOT. 7 More recently, atlas-DOT has been utilized together with the general linear model analysis, which further extended its feasibility of measuring hemodynamic changes in complex brain tasks.…”

“…Several groups have reported consistent and accurate results of brain hemodynamic changes under visual stimulation, 7 speech, 8 and risk decision-making. 5 It is well known that the human brain is naturally organized into groups of networks, with anatomical brain regions involved in either individualized processing or integration with other brain regions, to accomplish different functions. The brain networks experience changes in their properties under a variety of conditions, such as taking on different physical or mental tasks, facing strong emotions, 9 or undergoing normal aging.…”