- 标题
- 摘要
- 关键词
- 实验方案
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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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Neuroergonomics || The Use of Functional Near-Infrared Spectroscopy in Neuroergonomics
摘要： Functional Near Infrared Spectroscopy (fNIRS) is a multiwavelength optical technique: originally developed for the clinical monitoring of tissue oxygenation, it eventually evolved into a useful tool for functional neuroimaging studies. The technology has advanced and a variety of fNIRS instruments have been developed to monitor changes in local cerebral oxygenation by measuring the concentration changes of both deoxygenated hemoglobin (deoxy-Hb) and oxygenated hemoglobin (oxy-Hb). Various types of brain activities, such as motor and cognitive activities, have been studied using fNIRS.
关键词： hemodynamic response,neuroergonomics,cognitive workload,functional neuroimaging,fNIRS
更新于2025-09-10 09:29:36
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Neuroergonomics || Drowsiness Detection During a Driving Task Using fNIRS
摘要： In this chapter we investigate the potential aspects of passive BCI for drowsiness detection. We analyze the drowsy state through the brain’s hemodynamic response measured using fNIRS (Hong et al., 2014). Signals from the dorsolateral prefrontal cortex were used for this purpose. To acquire the maximum classification accuracy, statistical features (signal peak and signal mean), calculated over 0–7 s time windows, were used for a passive BCI.
关键词： passive BCI,drowsiness detection,hemodynamic response,dorsolateral prefrontal cortex,fNIRS
更新于2025-09-10 09:29:36
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Using prerecorded hemodynamic response functions in detecting prefrontal pain response: a functional near-infrared spectroscopy study
摘要： Currently, there is no method for providing a nonverbal objective assessment of pain. Recent work using functional near-infrared spectroscopy (fNIRS) has revealed its potential for objective measures. We conducted two fNIRS scans separated by 30 min and measured the hemodynamic response to the electrical noxious and innocuous stimuli over the anterior prefrontal cortex (aPFC) in 14 subjects. Based on the estimated hemodynamic response functions (HRFs), we first evaluated the test–retest reliability of using fNIRS in measuring the pain response over the aPFC. We then proposed a general linear model (GLM)-based detection model that employs the subject-specific HRFs from the first scan to detect the pain response in the second scan. Our results indicate that fNIRS has a reasonable reliability in detecting the hemodynamic changes associated with noxious events, especially in the medial portion of the aPFC. Compared with a standard HRF with a fixed shape, including the subject-specific HRFs in the GLM allows for a significant improvement in the detection sensitivity of aPFC pain response. This study supports the potential application of individualized analysis in using fNIRS and provides a robust model to perform objective determination of pain perception.
关键词： test–retest reliability,detection sensitivity,hemodynamic response function,anterior prefrontal cortex,pain,near-infrared spectroscopy
更新于2025-09-10 09:29:36
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Early Detection of Alzheimer’s Disease Using Non-invasive Near-Infrared Spectroscopy
摘要： Mild cognitive impairment (MCI) is a cognitive disorder characterized by memory impairment, wherein patients have an increased likelihood of developing Alzheimer’s disease (AD). The classification of MCI and different AD stages is therefore fundamental for understanding and treating the disease. This study aimed to comprehensively investigate the hemodynamic response patterns among various subject groups. Functional near-infrared spectroscopy (fNIRS) was employed to measure signals from the frontal and bilateral parietal cortices of healthy controls (n = 8), patients with MCI (n = 9), mild (n = 6), and moderate/severe AD (n = 7) during a digit verbal span task (DVST). The concentration changes of oxygenated hemoglobin (HbO) in various subject groups were thoroughly explored and tested. Result revealed that abnormal patterns of hemodynamic response were observed across all subject groups. Greater and steeper reductions in HbO concentration were consistently observed across all regions of interest (ROIs) as disease severity developed from MCI to moderate/severe AD. Furthermore, all the fNIRS-derived indexes were found to be significantly and positively correlated to the clinical scores in all ROIs (R ≥ 0.4, P < 0.05). These findings demonstrate the feasibility of utilizing fNIRS for the early detection of AD, suggesting that fNIRS-based approaches hold great promise for exploring the mechanisms underlying the progression of AD.
关键词： oxygenated hemoglobin,functional near-infrared spectroscopy,Alzheimer’s disease,hemodynamic response,mild cognitive impairment
更新于2025-09-09 09:28:46
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Adaptive filtering of physiological noises in fNIRS data
摘要： The study presents a recursive least?squares estimation method with an exponential forgetting factor for noise removal in functional near?infrared spectroscopy data and extraction of hemodynamic responses (HRs) from the measured data. The HR is modeled as a linear regression form in which the expected HR, the first and second derivatives of the expected HR, a short?separation measurement data, three physiological noises, and the baseline drift are included as components in the regression vector. The proposed method is applied to left?motor?cortex experiments on the right thumb and little finger movements in five healthy male participants. The algorithm is evaluated with respect to its performance improvement in terms of contrast?to?noise ratio in comparison with Kalman filter, low?pass filtering, and independent component method. The experimental results show that the proposed model achieves reductions of 77% and 99% in terms of the number of channels exhibiting higher contrast?to?noise ratios in oxy?hemoglobin and deoxy?hemoglobin, respectively. The approach is robust in obtaining consistent HR data. The proposed method is applied for both offline and online noise removal.
关键词： State space model,Hemodynamic response (HR),Exponential forgetting,Recursive least squares estimation (RLSE),Real time estimation,Functional near?infrared spectroscopy (fNIRS)
更新于2025-09-04 15:30:14
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A tiny macroscope to look into complex behavior
摘要： A macroscope mounted on the head of a freely moving transgenic rat can help shine light on complex behaviors. A macroscope is a microscopy device able to image at the mesoscopic scale, typically from hundreds of micrometers to centimeters. Such devices have been used to record neural activity in the brains of behaving rodents, mostly by measuring intracellular calcium dynamics in neurons. Usually the head of the animal needs to be restrained to ensure that the brain position remains stable relative to the imaging system, which limits the range of behaviors that can be studied. Alternatively, the use of miniaturized head-mounted microscopes allows for functional imaging in freely moving animals, which introduces the possibility of studying more sophisticated behaviors. However, most head-mounted microscopes can image only a relatively small field of view—typically less than 1 mm2, which is not compatible with the recording of neural activity across multiple brain regions. Also, these systems often cannot correct for image contamination caused by changes in blood flow due to neural activity, a phenomenon known as hemodynamic response. To overcome these limitations, David Tank and his team at Princeton University have developed cScope, a head-mounted macroscope able to image a field of view larger than 30 mm2 at the mesoscopic scale, without the need for animal head restraint. This is a low-cost 3D-printed plastic device equipped with two independent illumination sources, one for fluorescence imaging and one for hemodynamic response correction. The name cScope stands for “cortical macroscope,” underlining the ability to image various regions of the neocortical surface simultaneously, including sensory and motor regions as well as association regions. The researchers also developed new strains of transgenic rats expressing the genetically encoded calcium indicator GCaMP6f in a large proportion of neurons in the brain, by using pan-neuronal enhancers known to drive expression throughout the nervous system. In rats, fluorescent reporters are usually delivered by viral injection, which labels only a small region of tissue; therefore, the generation of transgenic rats expressing GCaMP6f in the neocortex, hippocampus, cerebellum, and other regions allows scientists to make the most of the large field of view available with the cScope. The team demonstrated the use of cScope to image spatiotemporal activity patterns across multiple brain areas, by imaging neuronal calcium dynamics in rats performing an evidence-based decision-making task. In this task each rat was exposed to random sequences of light flashes from its right and left sides, and it received a reward when it oriented toward the side with more flashes. The researchers observed that stimulus identity during cue presentation could be inferred from the activity in visual cortical regions, while the rat’s behavioral choice could be predicted on the basis of the activity in parietal cortical regions. These results confirm that complex behaviors recruit multiple brain regions, and that cScope can help scientists map activity in distant brain areas during behavioral tests. The combination of cScope and transgenic rats expressing the GCaMP6f calcium sensor expands the application of head-mounted microscopes into the mesoscopic scale and enables studies of global neural activity during a range of natural behaviors, including navigation, sleep, and social interactions. The authors of the study anticipate that cScope could also be used to image hemodynamic response, in addition to fluorescent reporters, in the brains of various animal models, including wild-type rats and even larger animals such as marmosets.
关键词： GCaMP6f,macroscope,hemodynamic response,transgenic rats,neural activity
更新于2025-09-04 15:30:14