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Perspective: Prospects of non-invasive sensing of the human brain with diffuse optical imaging
摘要： Since the initial demonstration of near-infrared spectroscopy (NIRS) for noninvasive measurements of brain perfusion and metabolism in the 1970s, and its application to functional brain studies (fNIRS) in the 1990s, the field of noninvasive optical studies of the brain has been continuously growing. Technological developments, data analysis advances, and novel areas of application keep advancing the field. In this article, we provide a view of the state of the field of cerebral NIRS, starting with a brief historical introduction and a description of the information content of the NIRS signal. We argue that NIRS and fNIRS studies should always report data of both oxy- and deoxyhemoglobin concentrations in brain tissue, as they complement each other to provide more complete functional and physiological information, and may help identify different types of confounds. One significant challenge is the assessment of absolute tissue properties, be them optical or physiological, so that relative measurements account for the vast majority of NIRS and fNIRS applications. However, even relative measurements of hemodynamics or metabolic changes face the major problem of a potential contamination from extracerebral tissue layers. Accounting for extracerebral contributions to fNIRS signals is one of the most critical barriers in the field. We present some of the approaches that were proposed to tackle this challenge in the study of cerebral hemodynamics and functional connectivity. Finally, we critically compare fNIRS and functional magnetic resonance imaging by relating their measurements in terms of signal and noise, and by commenting on their complementarity.
关键词： hemodynamics,functional connectivity,functional magnetic resonance imaging,human brain,near-infrared spectroscopy,diffuse optical imaging,non-invasive sensing,functional near-infrared spectroscopy
更新于2025-09-23 15:21:21
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The Supplementary Motor Area Responsible for Word Retrieval Decline After Acute Thalamic Stroke Revealed by Coupled SPECT and Near-Infrared Spectroscopy
摘要： Damage to the thalamus may affect cognition and language, but the underlying mechanism remains unknown. In particular, it remains a riddle why thalamic aphasia occasionally occurs and then mostly recovers to some degree. To explore the mechanism of the affected cognition and language, we used two neuroimaging techniques—single-photon emission computed tomography (SPECT), suitable for viewing the affected brain distribution after acute thalamic stroke, and functional near-infrared spectroscopy (f-NIRS), focusing on hemodynamic responses of the supplementary motor area (SMA) responsible for speech production in conjunction with the frontal aslant tract (FAT) pathway. SPECT yielded common perfusion abnormalities not only in the fronto–parieto–cerebellar loop, but also in the SMA, IFG and surrounding language-relevant regions. In NIRS sessions during a phonemic verbal fluency task, we found significant word retrieval decline in acute thalamic patients relative to age-matched healthy volunteers. Further, NIRS showed strong correlation between word retrieval and posterior SMA responses. In addition, follow-up NIRS exhibited increased bilateral SMA responses linked to improving word retrieval ability. The findings suggest that cognitive dysfunction may be related to the fronto–parieto–cerebellar loop, while language dysfunction is attributed to the SMA, IFG and language-related brain areas. SMA may contribute to the recovery of word retrieval difficulty and aphasia after thalamic stroke.
关键词： SPECT,hemodynamic response,perfusion,verbal fluency test,thalamic aphasia,FAT: frontal aslant tract,cerebro-cerebellar diaschisis,functional near-infrared spectroscopy (f-NIRS)
更新于2025-09-23 15:19:57
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Aging effects on prefrontal cortex oxygenation in a posture-cognition dual-task: an fNIRS pilot study
摘要： Background: The aging process alters upright posture and locomotion control from an automatically processed to a more cortically controlled one. The present study investigated a postural-cognitive dual-task paradigm in young and older adults using functional Near-Infrared Spectroscopy (fNIRS). Methods: Twenty healthy participants (10 older adults 72 ± 3 y, 10 young adults 23 ± 3 y) performed a cognitive (serial subtractions) and a postural task (tandem stance) as single-tasks (ST) and concurrently as a dual-task (DT) while the oxygenation levels of the dorsolateral prefrontal cortex (DLPFC) were measured. Results: In the cognitive task, young adults performed better than older adults in both conditions (ST and DT) and could further increase the number of correct answers from ST to DT (all ps ≤ 0.027) while no change was found for older adults. No significant effects were found for the postural performance. Cerebral oxygenation values (O2Hb) increased significantly from baseline to the postural ST (p = 0.033), and from baseline to the DT (p = 0.031) whereas no changes were found in deoxygenated hemoglobin (HHb). Finally, the perceived exertion differed between all conditions (p ≤ 0.003) except for the postural ST and the DT (p = 0.204). Conclusions: There was a general lack of age-related changes except the better cognitive performance under motor-cognitive conditions in young compared to older adults. However, the current results point out that DLPFC is influenced more strongly by postural than cognitive load. Future studies should assess the different modalities of cognitive as well as postural load.
关键词： Attention,Functional near-infrared spectroscopy (fNIRS),Postural control,Aging,Dual-tasking,Executive control,Balance,Elderly
更新于2025-09-19 17:15:36
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Conducting Hyperscanning Experiments with Functional Near-Infrared Spectroscopy
摘要： Concurrent brain recordings of two or more interacting persons, an approach termed hyperscanning, are gaining increasing importance for our understanding of the neurobiological underpinnings of social interactions, and possibly interpersonal relationships. Functional near-infrared spectroscopy (fNIRS) is well suited for conducting hyperscanning experiments because it measures local hemodynamic effects with a high sampling rate and, importantly, it can be applied in natural settings, not requiring strict motion restrictions. In this article, we present a protocol for conducting fNIRS hyperscanning experiments with parent-child dyads and for analyzing brain-to-brain synchrony. Furthermore, we discuss critical issues and future directions, regarding the experimental design, spatial registration of the fNIRS channels, physiological influences and data analysis methods. The described protocol is not specific to parent-child dyads, but can be applied to a variety of different dyadic constellations, such as adult strangers, romantic partners or siblings. To conclude, fNIRS hyperscanning has the potential to yield new insights into the dynamics of the ongoing social interaction, which possibly go beyond what can be studied by examining the activities of individual brains.
关键词： neuroscience,brain-to-brain synchrony,cooperation,fNIRS,parent-child interaction,hyperscanning,functional near-infrared spectroscopy
更新于2025-09-19 17:15:36
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Dynamic Activation Patterns of the Motor Brain Revealed by Diffuse Optical Tomography <sup>*</sup>
摘要： Diffuse optical tomography (DOT), a subset of functional near-infrared spectroscopy (fNIRS), is a noninvasive functional imaging modality for studying the human brain in normal and diseased conditions. It measures changes in concentrations of oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (Hb) in the blood vasculature of the brain. In contrast to functional magnetic resonance imaging (fMRI), the gold standard in human brain imaging, DOT offers the advantage of higher temporal resolution, portability, lower cost, multiple contrasts and usability for persons who cannot otherwise utilize MRI-based imaging modalities, including bedridden patients and infants, etc. The goal of the present study was to evaluate performance of a DOT method in studying dynamic patterns of brain activations involving motor control. CW-fNIRS data were acquired in four sessions from a healthy male participant when he performed a motor task in a block-design experiment. Results from experimental data showed pronounced activity in the primary motor cortex (M1), contralateral to the clenching hand. It was further observed that the M1 activity was consistent over four sessions. Furthermore, temporal dynamics of motor activity at each session further revealed well-sequenced activation patterns among M1, premotor cortex (PMC), and supplementary motor area (SMA). Timed ipsilateral motor activity suppression was also observed several seconds after the onset of contralateral M1 activity. More importantly, these temporal dynamics were similarly observed in all four sessions. These preliminary results suggest that the DOT method has the sensitivity, reliability, and spatio-temporal resolutions to study activities originated from the motor cortices. A full-scope evaluation and validation in more participants on the motor system can establish it as a promising neuroimaging tool to study, such as, infants at the risk of cerebral palsy or elders with Parkinson’s due to its portability and usability in clinical environments.
关键词： functional near-infrared spectroscopy,motor control,Diffuse optical tomography,brain activations,neuroimaging
更新于2025-09-19 17:13:59
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Assessing Neural Compensation with Visuospatial Working Memory Load using Near-Infrared Imaging
摘要： Alzheimer’s disease is characterized by the progressive deterioration of cognitive abilities particularly working memory while mild cognitive impairment (MCI) represents its prodrome. It is generally believed that neural compensation is intact in MCI but absent in Alzheimer’s disease. This study investigated the effects of increasing task load as a means to induce neural compensation through a novel visual working memory (VSWM) task using functional near-infrared spectroscopy (fNIRS). The bilateral prefrontal cortex (PFC) was explored due to its relevance in VSWM and neural compensation. A total of 31 healthy controls (HC), 12 patients with MCI and 18 patients with mild Alzheimers disease (mAD) were recruited. Although all groups showed sensitivity in terms of behavioral performance (i.e. score) towards increasing task load (level 1 to 3), only in MCI load effect on cortical response (as measured by fNIRS) was significant. At lower task load, bilateral PFC activation did not differ between MCI and HC. Neural compensation in the form of hyperactivation was only noticeable in MCI with a moderate task load. Lack of hyperactivation in mAD, coupled with significantly poorer task performance across task loads, suggested the inability to compensate due to a greater degree of neurodegeneration. Our findings provided an insight into the interaction of cognitive load theory and neural compensatory mechanisms. The experiment results demonstrated the feasibility of inducing neural compensation with the proposed VSWM task at the right amount of cognitive load. This may provide a promising avenue to develop an effective cognitive training and rehabilitation for dementia population.
关键词： mild cognitive impairment,visuospatial working memory,normal aging,functional near-infrared spectroscopy,neural compensation,mild Alzheimer’s disease
更新于2025-09-12 10:27:22
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Removing Task-Induced Superficial-Tissue Hemodynamics and Head Motion-Induced Artifacts in Functional Near-Infrared Spectroscopy
摘要： Functional near-infrared spectroscopy, a neuroimaging tool used to measure brain activity, is associated with two different types of artifacts: (a) task-induced super?cial-tissue hemodynamic artifacts derived from the scalp; and (b) motion artifacts caused by head motions. Recently, a simple and easy-to-use method, based on a general linear model incorporating super?cial hemodynamics model estimated from short-probe distance channels using principal component analysis, was proposed to remove task-induced super?cial-tissue artifacts. In the present study, we examined the effectiveness of this method in removing task-induced and head motion-induced super?cial-tissue hemodynamics. Thus, we conducted a motor experiment where participants were asked to perform grasping movements. During some sessions, head motions were generated in order to introduce motion artifacts. Although the removal of motion artifacts was not perfect, we found that analyses including the ?rst and second principal component (estimated from short-channels) showed a tendency to provide accurate detection of brain activity. This ?nding demonstrated the possibility of conducting effective analysis of functional near-infrared spectroscopy using general linear model and short-channels.
关键词： motion artifact removals,general linear model,functional near-infrared spectroscopy
更新于2025-09-10 09:29:36
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - A Modified Common Spatial Pattern Algorithm Customized for Feature Dimensionality Reduction in fNIRS-Based BCIs
摘要： Functional near-infrared spectroscopy (fNIRS) is a non-invasive multi-channel imaging tool for assessing brain activities, which has shown its high potential in brain-computer interface (BCI) technique. Most previous studies have focused on constructing high dimensional features from whole channels, adding to the complexity of their classifiers. Another multi-channel source for BCI is electroencephalograph (EEG), which possesses different spatial and temporal features from fNIRS. In EEG field, Common Spatial Pattern (CSP) algorithm is widely used aimed at dimensionality reduction. In our article, we modified it based on the characteristics of fNIRS and evaluated its effectiveness in discriminating Mental Arithmetic (MA) against resting status in an open-access dataset. The Modified Common Spatial Pattern algorithm significantly outperforms CSP algorithm in fNIRS-based BCI and shows its potential in further BCI related explorations.
关键词： Common Spatial Pattern (CSP),Mental Arithmetic (MA),Modified Common Spatial Pattern (MCSP),brain-computer interface (BCI),Functional near-infrared spectroscopy (fNIRS)
更新于2025-09-10 09:29:36
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Neuroergonomics || Functional Near-Infrared Spectroscopy
摘要： The mission of social psychology is to understand “how the thoughts, feelings, and behaviour of individuals are influenced by the actual, imagined, or implied presence of others.” The mission of social neuroscience is to understand the neural and broader biological underpinnings of social psychological phenomena. Like every scientific discipline, the success of social neuroscience rests on the effectiveness of its methods. Recent years have witnessed a proliferation of methods that hold promise for advancing social neuroscience. One such method is continuous-wave functional near-infrared spectroscopy (fNIRS), a functional neuroimaging technique that can be used to measure brain activity noninvasively. In this chapter we demonstrate the utility of fNIRS for social neuroscience in identifying well-established patterns of prefrontal activity when people make self- and other-referential judgments.
关键词： social neuroscience,self-referential judgments,prefrontal activity,functional near-infrared spectroscopy,fNIRS
更新于2025-09-10 09:29:36
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Non-neuronal evoked and spontaneous hemodynamic changes in the anterior temporal region of the human head may lead to misinterpretations of functional near-infrared spectroscopy signals
摘要： Several functional near-infrared spectroscopy (fNIRS) studies report their findings based on changes of a single chromophore, usually concentration changes of oxygenated hemoglobin ([O2Hb]) or deoxygenated hemoglobin (HHb). However, influence of physiological actions may differ depending on which element is considered and the assumption that the chosen measure correlates with the neural response of interest might not hold. By assessing the correlation between [O2Hb] and [HHb] in task-evoked activity as well as resting-state data, we identified a spatial dependency of non-neuronal hemodynamic changes in the anterior temporal region of the human head. Our findings support the importance of reporting and discussing fNIRS outcomes obtained with both chromophores ([O2Hb] and [HHb]), in particular, for studies concerning the anterior temporal region of the human head. This practice should help to achieve a physiologically correct interpretation of the results when no measurements with short-distance channels are available while employing continuous-wave fNIRS systems.
关键词： superficial temporal vessels,temporal lobe,optical neuroimaging,temporalis muscle,scalp blood flow,extracerebral signal contamination,functional near-infrared spectroscopy
更新于2025-09-10 09:29:36