Functional near-infrared spectroscopy (fNIRS) is an increasingly popular technology for studying social cognition. In particular, fNIRS permits simultaneous measurement of hemodynamic activity in two ...or more individuals interacting in a naturalistic setting. Here, we used fNIRS hyperscanning to study social cognition and communication in human dyads engaged in cooperative and obstructive interaction while they played the game of Jenga™. Novel methods were developed to identify synchronized channels for each dyad and a structural node-based spatial registration approach was utilized for inter-dyad analyses. Strong inter-brain neural synchrony (INS) was observed in the posterior region of the right middle and superior frontal gyrus, in particular Brodmann area 8 (BA8), during cooperative and obstructive interaction. This synchrony was not observed during the parallel game play condition and the dialog section, suggesting that BA8 was involved in goal-oriented social interaction such as complex interactive movements and social decision-making. INS was also observed in the dorsomedial prefrontal cortex (dmPFC), in particular Brodmann 9, during cooperative interaction only. These additional findings suggest that BA9 may be particularly engaged when theory-of-mind (ToM) is required for cooperative social interaction. The new methods described here have the potential to significantly extend fNIRS applications to social cognitive research.
Significance: Functional near-infrared spectroscopy (fNIRS) has been widely used to probe human brain function during task state and resting state. However, the existing analysis toolboxes mainly ...focus on task activation analysis, few software packages can assist resting-state fNIRS studies.
Aim: We aimed to provide a versatile and easy-to-use toolbox to perform analysis for both resting state and task fNIRS.
Approach: We developed a MATLAB toolbox called NIRS-KIT that works for both resting-state analysis and task activation detection.
Results: NIRS-KIT implements common and necessary processing steps for performing fNIRS data analysis, including data preparation, quality control, preprocessing, individual-level analysis, group-level statistics with several popular statistical models, and multiple comparison correction methods, and finally results visualization. For resting-state fNIRS analysis, functional connectivity analysis, graph theory-based network analysis, and amplitude of low-frequency fluctuations analysis are provided. Additionally, NIRS-KIT also supports activation analysis for task fNIRS.
Conclusions: NIRS-KIT offers an open source tool for researchers to analyze resting-state and/or task fNIRS data in one suite. It contains several key features: (1) good compatibility, supporting multiple fNIRS recording systems, data formats of NIRS-SPM and Homer2, and the shared near-infrared spectroscopy format data format recommended by the fNIRS society; (2) flexibility, supporting customized preprocessing scripts; (3) ease-to-use, allowing processing fNIRS signals in batch manner with user-friendly graphical user interfaces; and (4) feature-packed data viewing and result visualization. We anticipate that this NIRS-KIT will facilitate the development of the fNIRS field.
We report experimental 2D infrared (2D IR) spectra of coherent light–matter excitations—molecular vibrational polaritons. The application of advanced 2D IR spectroscopy to vibrational polaritons ...challenges and advances our understanding in both fields. First, the 2D IR spectra of polaritons differ drastically from free uncoupled excitations and a new interpretation is needed. Second, 2D IR uniquely resolves excitation of hybrid light–matter polaritons and unexpected dark states in a state-selective manner, revealing otherwise hidden interactions between them. Moreover, 2D IR signals highlight the impact of molecular anharmonicities which are applicable to virtually all molecular systems. A quantum-mechanical model is developed which incorporates both nuclear and electrical anharmonicities and provides the basis for interpreting this class of 2D IR spectra. This work lays the foundation for investigating phenomena of nonlinear photonics and chemistry of molecular vibrational polaritons which cannot be probed with traditional linear spectroscopy.
The development of novel miniaturized wireless and wearable functional near‐infrared spectroscopy (fNIRS) devices has paved the way for new functional brain imaging that could revolutionize the ...cognitive research fields. Over the past few decades, several studies have been conducted with conventional fNIRS systems that have demonstrated the suitability of this technology for a wide variety of populations and applications, to investigate both the healthy brain and the diseased brain. However, what makes wearable fNIRS even more appealing is its capability to allow measurements in everyday‐life scenarios that are not possible with other gold‐standard neuroimaging modalities, such as functional magnetic resonance imaging. This could have a huge impact on the way we explore the neural bases and mechanisms underpinning human brain functioning. The aim of this review is to provide an overview of studies conducted with wearable fNIRS in naturalistic settings in the field of cognitive neuroscience. In addition, we present the challenges associated with the use of wearable fNIRS in unrestrained contexts, discussing solutions that will allow accurate inference of functional brain activity. Finally, we provide an overview of the future perspectives in cognitive neuroscience that we believe would benefit the most from the study of wearable fNIRS devices.
Key points
The majority of intrapartum decelerations are widely believed to be mediated by the baroreflex secondary to brief umbilical cord occlusions (UCOs) but this remains unproven.
We examined ...the responses to brief‐UCOs in fetal sheep and compared these to a phenylephrine‐stimulated baroreflex in a separate cohort. A further cohort was instrumented with near‐infrared spectroscopy to measure cerebral oxygenation during UCO.
The first 3–4 s of the brief‐UCOs were consistent with a baroreflex, and associated with a minor fall in fetal heart rate (FHR). Thereafter, the remainder of the FHR decelerations were highly consistent with the peripheral chemoreflex.
The baroreflex is not sufficient to produce deep, rapid decelerations characteristic of variable decelerations and it is therefore likely to be a minor contributor to intrapartum decelerations.
Fetal heart rate (FHR) monitoring is widely used to assess fetal wellbeing during labour, yet the physiology underlying FHR patterns remains incompletely understood. The baroreflex is widely believed to mediate brief intrapartum decelerations, but evidence supporting this theory is lacking. We therefore investigated the physiological changes in near‐term fetal sheep during brief repeated umbilical cord occlusions (brief‐UCOs, n = 15). We compared this to separate cohorts that underwent a phenylephrine challenge to stimulate the baroreflex (n = 9) or were instrumented with near‐infrared spectroscopy and underwent prolonged 15‐min complete UCO (prolonged‐UCO, n = 9). The first 3–4 s of brief‐UCOs were associated with hypertension (P = 0.000), a fall in FHR by 9.7–16.9 bpm (P = 0.002). The FHR/MAP relationship during this time was consistent with that observed during a phenylephrine‐induced baroreflex. At 4–5 s, the FHR/MAP relationship began to deviate from the phenylephrine baroreflex curve as FHR fell independently of MAP until its nadir in association with intense peripheral vasoconstriction (P = 0.000). During prolonged‐UCO, cerebral oxygenation remained steady until 4 s after the start of prolonged‐UCO, and then began to fall (P = 0.000). FHR and cerebral oxygenation then fell in parallel until the FHR nadir. In conclusion, the baroreflex has a minor role in mediating the first 3–4 s of FHR decelerations during complete UCO, but thereafter the peripheral chemoreflex is the dominant mediator. Overall, the baroreflex is neither necessary nor sufficient to produce deep, rapid decelerations characteristic of variable decelerations; it is therefore likely to be a minor contributor to intrapartum decelerations.
Key points
The majority of intrapartum decelerations are widely believed to be mediated by the baroreflex secondary to brief umbilical cord occlusions (UCOs) but this remains unproven.
We examined the responses to brief‐UCOs in fetal sheep and compared these to a phenylephrine‐stimulated baroreflex in a separate cohort. A further cohort was instrumented with near‐infrared spectroscopy to measure cerebral oxygenation during UCO.
The first 3–4 s of the brief‐UCOs were consistent with a baroreflex, and associated with a minor fall in fetal heart rate (FHR). Thereafter, the remainder of the FHR decelerations were highly consistent with the peripheral chemoreflex.
The baroreflex is not sufficient to produce deep, rapid decelerations characteristic of variable decelerations and it is therefore likely to be a minor contributor to intrapartum decelerations.
Three data fusion strategies (low-llevel, mid-llevel, and high-llevel) combined with a multivariate classification algorithm (random forest, RF) were applied to authenticate the geographical origins ...of
Panax notoginseng
collected from five regions of Yunnan province in China. In low-level fusion, the original data from two spectra (Fourier transform mid-IR spectrum and near-IR spectrum) were directly concatenated into a new matrix, which then was applied for the classification. Mid-level fusion was the strategy that inputted variables extracted from the spectral data into an RF classification model. The extracted variables were processed by iterate variable selection of the RF model and principal component analysis. The use of high-level fusion combined the decision making of each spectroscopic technique and resulted in an ensemble decision. The results showed that the mid-level and high-level data fusion take advantage of the information synergy from two spectroscopic techniques and had better classification performance than that of independent decision making. High-level data fusion is the most effective strategy since the classification results are better than those of the other fusion strategies: accuracy rates ranged between 93% and 96% for the low-level data fusion, between 95% and 98% for the mid-level data fusion, and between 98% and 100% for the high-level data fusion. In conclusion, the high-level data fusion strategy for Fourier transform mid-IR and near-IR spectra can be used as a reliable tool for correct geographical identification of
P. notoginseng
.
Graphical abstract
The analytical steps of Fourier transform mid-IR and near-IR spectral data fusion for the geographical traceability of
Panax notoginseng
•Analysis of fresh fruit and vegetables by FT-MIR spectroscopy is reviewed.•The review covers more than 40 genera and more than 40 different crop attributes.•Best-practice chemometric approaches for ...analysing these samples are outlined.•Applications are described for portable, lab-based and FT-microscope systems.•Issues impeding uptake of this novel technique are identified in future directions.
In recent years, decreased cost, miniaturisation and advances in computing power and data processing software have led to widespread introduction of Fourier-transform (FT) spectrometers across different disciplines. In this review, applications of FT mid infrared (FT-MIR) spectroscopy are summarised covering the analysis of fresh fruit and vegetables, and some of their processed products (juices, jam, oil, wine). The paper also outlines basic principles of vibrational spectroscopy in the MIR region, using sugars and acids in fruit juices as exemplars of spectral interpretation. Laboratory-based spectrometers, FT-MIR microspectroscopy for high-resolution mapping, and portable, hand-held units for field work are described. Applications involving these systems, which extend to more than 40 genera, and more than 40 different crop attributes, include; assessing the maturity or quality attributes of produce, screening progeny from breeding programmes, determination of bioactive contents and plant metabolites, determining the extent of adulteration and authenticating products for type or geographic location, and localisation of metabolites within plant cells. Principles outlining best-practice for developing calibration models in fruit and vegetable-based systems are also included.
This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous ...wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy- and deoxyhemoglobin and approaches for data analysis are also reviewed.
From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects.
•Comprehensive review on continuous wave functional near infrared imaging•Overview of currently available commercial near infrared imaging instrumentation•Review of technical aspects such as light sources, detectors and sensor arrangements•Review of methodological aspects, algorithms, and data analysis and its tool boxes
New Findings
What is the central question of this study?
What are the effects of the menstrual (early follicular and mid‐luteal) or monophasic oral contraceptive (inactive‐ and active‐pill) cycle ...phases on vascular reperfusion of lower limb microvasculature in healthy, active women using the near‐infrared spectroscopy (NIRS) vascular occlusion test (VOT) technique?
What is the main finding and its importance?
We demonstrated that vascular responsiveness in the lower limb microvasculature remained unchanged between the early follicular and mid‐luteal phases of the menstrual cycle and inactive‐ and active‐pill phases of the oral contraceptive cycle. These data support that controlling for the cycle phases, within the specific times evaluated in this study, might not be necessary when assessing NIRS‐VOT reperfusion rates.
The objective was to examine whether the menstrual or monophasic oral contraceptive cycle phases affect microvascular responsiveness of the lower limb in healthy, active women. During the follicular or inactive‐pill phase and the luteal or active‐pill phase of the menstrual or oral contraceptive cycle, respectively, 15 non‐oral contraceptive users (mean ± SD; 27 ± 6 years of age) and 15 monophasic oral contraceptive users (24 ± 4 years of age) underwent a lower‐limb vascular occlusion test (5 min baseline, 5 min occlusion and 8 min post cuff release). Menstrual cycle phases were verified using an ovulation test. Vascular responsiveness was assessed by calculating the near‐infrared spectroscopy‐derived muscle oxygen saturation (StO2) reperfusion slope (slope 2 StO2) and the post occlusion StO2 area under the curve (StO2AUC) of the tibialis anterior muscle. There were no differences in the reperfusion slope (as a percentage per second; follicular, 1.18 ± 0.48; luteal, 1.05 ± 0.48, inactive‐pill, 0.95 ± 0.23; and active‐pill, 0.87 ± 0.36; P = 0.09) and area under the curve (as a product of the percentage and seconds; follicular, 1067 ± 562; luteal, 918 ± 414, inactive‐pill, 945 ± 702; and active‐pill, 750 ± 519; P = 0.09) between the phases of the menstrual or oral contraceptive cycle, regardless of pill generation. The duration of oral contraceptive use was not associated with changes in slope 2 StO2 (r = 0.02, P = 0.94) or StO2AUC (r = −0.34, P = 0.22) between cycle phases. In conclusion, vascular responsiveness remained unchanged between the early follicular and mid‐luteal phases of the menstrual cycle and the inactive‐pill and active‐pill phases of the oral contraceptive cycle.
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