Wearables and the Brain

The brain is the last frontier for wearable sensing. Commercially available wearables can monitor your vital signs and physical activity, but few have the ability to monitor what goes on inside your head. With the advent of new wearable and portable neuroimaging technologies, this situation might be about to change, with profound implications for neuroscience and for wearables. One of the main attractions of wearables, and wearable sensing, comes from the proximity of the devices to the human body and to the wealth of information that might be gathered from being so close. Yet when it comes to sensing the brain-and, even more so, our minds- significant difficulties arise. First among these is the inadequacy of available sensing technology. It is relatively easy to sense the movement of a person's arm, but much more difficult to gain access to the workings of their brain. Second, and perhaps more fundamentally, we still do not really know enough about how brains actually work in the real-world and outside the restrained laboratory setting-and it is hard to sense and make use of what we do not quite understand

Simultaneous fNIRS and thermal infrared imaging during cognitive task reveal autonomic correlates of prefrontal cortex activity

Functional Near Infrared-Spectroscopy (fNIRS) represents a powerful tool to non-invasively study task-evoked brain activity. fNIRS assessment of cortical activity may suffer for contamination by physiological noises of different origin (e.g. heart beat, respiration, blood pressure, skin blood flow), both task-evoked and spontaneous. Spontaneous changes occur at different time scales and, even if they are not directly elicited by tasks, their amplitude may result task-modulated. In this study, concentration changes of hemoglobin were recorded over the prefrontal cortex while simultaneously recording the facial temperature variations of the participants through functional infrared thermal (fIR) imaging. fIR imaging provides touch-less estimation of the thermal expression of peripheral autonomic. Wavelet analysis revealed task-modulation of the very low frequency (VLF) components of both fNIRS and fIR signals and strong coherence between them. Our results indicate that subjective cognitive and autonomic activities are intimately linked and that the VLF component of the fNIRS signal is affected by the autonomic activity elicited by the cognitive task. Moreover, we showed that task-modulated changes in vascular tone occur both at a superficial and at larger depth in the brain. Combined use of fNIRS and fIR imaging can effectively quantify the impact of VLF autonomic activity on the fNIRS signals

Using fiberless, wearable fNIRS to monitor brain activity in real-world cognitive tasks

Functional Near Infrared Spectroscopy (fNIRS) is a neuroimaging technique that uses near-infrared light to monitor brain activity. Based on neurovascular coupling, fNIRS is able to measure the haemoglobin concentration changes secondary to neuronal activity. Compared to other neuroimaging techniques, fNIRS represents a good compromise in terms of spatial and temporal resolution. Moreover, it is portable, lightweight, less sensitive to motion artifacts and does not impose significant physical restraints. It is therefore appropriate to monitor a wide range of cognitive tasks (e.g., auditory, gait analysis, social interaction) and different age populations (e.g., new-borns, adults, elderly people). The recent development of fiberless fNIRS devices has opened the way to new applications in neuroscience research. This represents a unique opportunity to study functional activity during real-world tests, which can be more sensitive and accurate in assessing cognitive function and dysfunction than lab-based tests. This study explored the use of fiberless fNIRS to monitor brain activity during a real-world prospective memory task. This protocol is performed outside the lab and brain haemoglobin concentration changes are continuously measured over the prefrontal cortex while the subject walks around in order to accomplish several different tasks

Combining wearable fNIRS and immersive virtual reality to study preschoolers’ social development: a proof-of-principle study on preschoolers’ social preference

Data availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.Supplementary data is available online at: https://academic.oup.com/oons/article/doi/10.1093/oons/kvad012/7475300?login=false#433457515 .Copyright © The Author(s) 2023. A child’s social world is complex and rich, but has traditionally been assessed with conventional experiments where children are presented with repeated stimuli on a screen. These assessments are impoverished relative to the dynamics of social interactions in real life, and can be challenging to implement with preschoolers, who struggle to comply with strict lab rules. The current work meets the need to develop new platforms to assess preschoolers’ social development, by presenting a unique virtual-reality set-up combined with wearable functional near-infrared spectroscopy (fNIRS). As a proof-of-principle, we validated this platform by measuring brain activity during self-guided social interaction in 3-to-5-year-olds, which is under-investigated, yet crucial to understand the basis of social interactions in preschoolers. 37 preschoolers chose an interaction partner from one of 4 human-like avatars of different gender and age. We recorded spontaneous brain fluctuations from the frontal and temporoparietal regions (notably engaged in social-categorization and preference) while children played a bubble-popping game with a preferred and an assigned avatar. 60% of the participants chose to play with the same-gender and same-age avatar. However, this result was driven by females (>80% vs. 50% in males). Different fronto-temporoparietal connectivity patterns when playing with the two avatars were observed, especially in females. We showed the feasibility of using a novel set-up to naturalistically assess social preference in preschoolers, which was assessed at the behavioural and functional connectivity level. This work provides a first proof-of-principle for using cutting-edge technologies and naturalistic experiments to study social development, opening new avenues of research.Leverhulme Trust and undertaken at the Centre for Brain and Cognitive Development, Birkbeck College, London. C.B. acknowledges support from the Early Career Fellowship Leverhulme Trust (ECF-2021-174). P.P. acknowledges support from the Wellcome Trust (212979/Z/18/Z). E.J.H.J. acknowledges support from the Economic and Social Research Council (ES/R009368/1) and from the Medical Research Council (MR/K021389/1; MR/T003057/1

Warping-based co-registration of thermal infrared images: Study of factors influencing its applicability

A relevant issue for processing biomedical thermal imaging data is the availability of tools for objective and quantitative comparison of images across different conditions or subjects. To this goal, a solution can be offered by projecting the thermal distribution data onto a fictitious template to obtain a common reference for comparison across cases or subjects. In this preliminary study, we tested the feasibility of applying a warping procedure on infrared thermal images. Fifteen thermal images of checkerboard were recorded at three different distances and five different angles in order to evaluate which factor mostly influences the warping accuracy. The accuracy of three different warping transformation models (local weighted mean (LWM), polynomial, affine) was tested by comparing the positioning error between users’ selected fiduciary points on each thermal image and their corresponding reference position assigned on the template image. Fifteen users, divided into three groups upon on their experience in thermal imaging processing, participated in this study in order to evaluate the effect of experience in applying a warping procedure to the analysis of thermal infrared images. The most relevant factor influencing the positioning and thermal errors is the acquisition distance, while the users’ level of experience and the inclination angle do not seem to play the same importance. Comparing the three transformations, the LWM seems to be the best in terms of minimizing the two categories of errors. This preliminary work helps to understand the limits and the possibilities of applying warping techniques for objective, quantitative and automatic thermal image comparisons

A novel GLM-based method for the Automatic IDentification of functional Events (AIDE) in fNIRS data recorded in naturalistic environments.

Recent technological advances have allowed the development of portable functional Near-Infrared Spectroscopy (fNIRS) devices that can be used to perform neuroimaging in the real-world. However, as real-world experiments are designed to mimic everyday life situations, the identification of event onsets can be extremely challenging and time-consuming. Here, we present a novel analysis method based on the general linear model (GLM) least square fit analysis for the Automatic IDentification of functional Events (or AIDE) directly from real-world fNIRS neuroimaging data. In order to investigate the accuracy and feasibility of this method, as a proof-of-principle we applied the algorithm to (i) synthetic fNIRS data simulating both block-, event-related and mixed-design experiments and (ii) experimental fNIRS data recorded during a conventional lab-based task (involving maths). AIDE was able to recover functional events from simulated fNIRS data with an accuracy of 89%, 97% and 91% for the simulated block-, event-related and mixed-design experiments respectively. For the lab-based experiment, AIDE recovered more than the 66.7% of the functional events from the fNIRS experimental measured data. To illustrate the strength of this method, we then applied AIDE to fNIRS data recorded by a wearable system on one participant during a complex real-world prospective memory experiment conducted outside the lab. As part of the experiment, there were four and six events (actions where participants had to interact with a target) for the two different conditions respectively (condition 1: social-interact with a person; condition 2: non-social-interact with an object). AIDE managed to recover 3/4 events and 3/6 events for conditions 1 and 2 respectively. The identified functional events were then corresponded to behavioural data from the video recordings of the movements and actions of the participant. Our results suggest that "brain-first" rather than "behaviour-first" analysis is possible and that the present method can provide a novel solution to analyse real-world fNIRS data, filling the gap between real-life testing and functional neuroimaging

A new multichannel broadband NIRS system for quantitative monitoring of brain hemodynamics and metabolism during seizures

We present a newly developed multichannel broadband NIRS (or bNIRS) system that has the capacity to measure changes in light attenuation of 308 NIR wavelengths (610nm to 918nm) simultaneously over 16 different brain locations. To achieve this the instrument uses a lens based spectrometer with a front-illuminated CCD that has a sensor size of 26.8x26mm. This large CCD detector allows the simultaneous binning of 16 detector fibres. The software uses the UCLn algorithm to quantify the changes in oxy-, deoxy- haemoglobin concentration (HbO2, HHb) and oxidised cytochrome-coxidase (oxCCO) simultaneously over 16 different brain locations with 1second sampling rate. We demonstrate the use of the instrument in quantifying brain tissue oxygenation and metabolic activity simultaneously with electrical changes as measured with EEG in children with seizures

Quercetin and Cancer Chemoprevention

Several molecules present in the diet, including flavonoids, can inhibit the growth of cancer cells with an ability to act as “chemopreventers”. Their cancer-preventive effects have been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis as well as the antioxidant functions. The antioxidant activity of chemopreventers has recently received a great interest, essentially because oxidative stress participates in the initiation and progression of different pathological conditions, including cancer. Since antioxidants are capable of preventing oxidative damage, the wide use of natural food-derived antioxidants is receiving greater attention as potential anti-carcinogens. Among flavonoids, quercetin (Qu) is considered an excellent free-radical scavenging antioxidant, even if such an activity strongly depends on the intracellular availability of reduced glutathione. Apart from antioxidant activity, Qu also exerts a direct, pro-apoptotic effect in tumor cells, and can indeed block the growth of several human cancer cell lines at different phases of the cell cycle. Both these effects have been documented in a wide variety of cellular models as well as in animal models. The high toxicity exerted by Qu on cancer cells perfectly matches with the almost total absence of any damages for normal, non-transformed cells. In this review we discuss the molecular mechanisms that are based on the biological effects of Qu, and their relevance for human health

Quantification of inter-brain coupling: A review of current methods used in haemodynamic and electrophysiological hyperscanning studies

Hyperscanning is a form of neuroimaging experiment where the brains of two or more participants are imaged simultaneously whilst they interact. Within the domain of social neuroscience, hyperscanning is increasingly used to measure inter-brain coupling (IBC) and explore how brain responses change in tandem during social interaction. In addition to cognitive research, some have suggested that quantification of the interplay between interacting participants can be used as a biomarker for a variety of cognitive mechanisms aswell as to investigate mental health and developmental conditions including schizophrenia, social anxiety and autism. However, many different methods have been used to quantify brain coupling and this can lead to questions about comparability across studies and reduce research reproducibility. Here, we review methods for quantifying IBC, and suggest some ways moving forward. Following the PRISMA guidelines, we reviewed 215 hyperscanning studies, across four different brain imaging modalities: functional near-infrared spectroscopy (fNIRS), functional magnetic resonance (fMRI), electroencephalography (EEG) and magnetoencephalography (MEG). Overall, the review identified a total of 27 different methods used to compute IBC. The most common hyperscanning modality is fNIRS, used by 119 studies, 89 of which adopted wavelet coherence. Based on the results of this literature survey, we first report summary statistics of the hyperscanning field, followed by a brief overview of each signal that is obtained from each neuroimaging modality used in hyperscanning. We then discuss the rationale, assumptions and suitability of each method to different modalities which can be used to investigate IBC. Finally, we discuss issues surrounding the interpretation of each method

Cardiovascular Effects of Whole-Body Cryotherapy in Non-professional Athletes

Objectives: The study aimed to investigate changes in heart rate, blood pressure, respiratory rate, oxygen saturation, and body temperature in non-professional trained runners during whole body cryotherapy (WBC). Methods: Ten middle-distance runners received 3 once-a-day sessions of WBC. Subjects underwent BP measurements and ECG recorded before and immediately after the daily WBC session. During WBC we recorded a single lead trace (D1) for heart rhythm control. In addition, the 5 vital signs Blood pressure, heart rate, respiratory rate, oxygen saturation, and body temperature were monitored before, during, and after all WBC session. Results: We did not report significant changes in ECG main intervals (PR, QT, and QTc). Mean heart rate changed from 50.98 ± 4.43 bpm (before) to 56.83 ± 4.26 bpm after WBC session (p < 0.05). The mean systolic blood pressure did not change significantly during and after WBC [b baseline: 118 ± 5 mmHg, changed to 120 ± 3 mmHg during WBC, and to 121 ± 2 mmHg after session (p < 0.05 vs. baseline)]. Mean respiratory rate did not change during WBC as well as oxygen saturations (98 vs. 99%). Body temperature was slightly increased after WBC, however it remains within physiological values Conclusion: In non-professional athletes WBC did not affect cardiovascular response and can be safely used. However, further studies are required to confirm these promising results of safety in elderly non-athlete subjects