How do I optimize my signal quality?

We are excited to share with you our latest video from our expert colleagues here at NIRx. In this latest release, Demetris take us step by step through the Signal Quality Guide. This guide provides you with the tips and tricks to make sure your signal quality is excellent before beginning your experiment.

This video goes through how to quantitatively and qualitatively assess signal quality.

In Part 1, Demetris takes us through how to assess signal quality. Part 2 shows how to troubleshoot the challenges when things are less than perfect. These two sections follow the Signal Quality Guidelines, available as a PDF on our Support Site. In Part 3, with the help of our colleagues, we show a real-time example of set up, checks, and troubleshooting.

Um Workshop de fNIRS na America latina / fNIRS Workshop in Latin America!

Written by: Cesar Noronha, M

Pictures: Mariana Ceci/Ascom ISD

(Português abaixo)

fNIRS Workshop in Latin America!

2022 started off on the right foot in Latin America with workshops for participants from all regions of Brazil!

In February, NIRx, together with Brain Support, and Instituto Santos Dumont, hosted a two-day workshop with presentations and hands-on sessions. This event featured morning lectures and practical sessions in the afternoons.

Maria Adelia presenting the hands-on session.

In the mornings, international speakers were invited to talk about their fNIRS research. They introduced advantages of fNIRS, challenges, experimental design, special considerations and analyses. On the last day, NIRx held a closing talk discussing the fundamentals of fNIRS.

Cesar Noronha setting up the NIRS cap.

In the afternoons, there were practical sessions demonstrating NIRSport2 data acquisition on the first day, and NIRSport1 on the second day. This was all streamed online.

After the sessions, we worked with each research group on their specific questions and challenges. The focus of the first day was the assembly design and data acquisition and the second day was the analysis and interpretation.

Representatives of at least 4 different research groups that use or want to use fNIRS in their research were present. We love to share fNIRS technology. Check out our webinars or events pages for more upcoming workshops.

The lectures are in Instituto Santos Dumont open YouTube channel for sharing:

NIRx Staff - Maria Adelia de Aratanha, Cesar Noronha
Brain Support Staff - Daniel Machado

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Um Webinar de fNIRS na America latina!

Iniciamos 2022 com o pé direito na américa latina! Realizamos seminários com convidados de varias regiões do Brasil!

Em Fevereiro os pesquisadores e entusiastas de fNIRS da America Latina tiveram um evento para chamar de seu. A NIRx junto da Brain Suport e o Instuto Santos Dumont realizaram um webinar de dois dias com apresentações e sessões de hands-on!

Maria Adelia explains the multiplicity of fNIRS systems

Este foi um workshop de dois dias muito interessante. Tivemos palestras inteiras de manhã e NIRx e sessões práticas durante as tardes. Pela manhã tivemos palestrantes internacionais falando sobre suas pesquisas com fNIRS, desafios, vantagens, desenho experimental, considerações especiais e análises. No último dia, o NIRx realizou uma palestra de encerramento falando sobre os fundamentos do fNIRS.

Na parte da tarde, tivemos uma sessão prática gravada onde mostramos a aquisição de dados NIRSport2 no primeiro dia e NIRSport1 no segundo dia. Após a sessão gravada, trabalhávamos com cada grupo de pesquisa em suas questões e desafios específicos. O foco do primeiro dia foi o desenho da montagem e aquisição de dados e no segundo dia foi a análise e interpretação.

Researchers from different laboratories discuss an experimental design proposed during the seminar

Tivemos a presença de representantes de pelo menos 4 diferentes grupos de pesquisa que utilizam ou utilização fNIRS em suas pesquisas. Os pesquisadores presentes além de elogiarem bastante o webinar já perguntaram quando será o próximo!

As palestras estão no canal do YouTube do Instituto Santos Dumont aberto para compartilhamento:

The Latin America fNIRS community in attendance

Thank you to all who attended! See you next time!

A Practical Guide for fNIRS and EEG

How do you combine fNIRS and EEG? And why should you?

Forward written by Brain Products

Combining different neurophysiological technologies offers the possibility of examining cortical activity in a more comprehensive compared to one modality alone. In particular, the co-registration of EEG and fNIRS has a series of functional and practical advantages, since they capture different but complementary aspects of the brain’s activity. 

EEG directly measures the fast changes in electrical activity connected to neuronal function. This signal has an exquisite temporal resolution (millisecond precision) but limited spatial resolution. fNIRS measures changes in the brain’s hemodynamic response, and, specifically, localizes the slower changes in oxygen metabolism that follow neural activation.  This signal has a good spatial resolution (<1 cm) but a limited temporal resolution (~ 3 to 6 seconds). 

Besides being complementary to each other, an additional advantage is that EEG and fNIRS signals do not interfere with each other, making data recording and analysis more straightforward than with other modalities (e.g. fMRI, MEG). While EEG uses electrodes to measure scalp potentials, fNIRS uses optodes (light sources and detectors) to measure cortical hemodynamic response.

How to combine EEG and fNIRS, a practical guide

We have written a practical step by step guide that details how to conduct an EEG and fNIRS experiment using the examples of NIRx and Brain Products devices. Download your free copy below. It is also available on the NIRx Support Site for Customers.

NIRx Accessory Kits - Explainer Videos

What accessories can you expect with a fNIRS device from NIRx?

It’s arrived! What can you expect included in the delivery of your NIRx fNIRS system?

We have made some videos that give a walk-through of the items that will arrive in two of the three cases. These are the Starter Kit and Cap Kit. In these kits you will find everything that you need and more to prepare and run your fNIRS experiments with NIRx devices.

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In the Starter Kit you'll find accessories to set up your experiment, these include a tape measure, links, headlamp and more.

In the Starter Kit Video, each item is described and it’s use explained. For example, Velcro straps are used for cable management.

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The Cap Kit has all the items necessary for preparing your fNIRS cap. Here you’ll find your NIRScaps, optode holders and bases, short channels, phantom, and much more.

Cap Kit Video: a brief description of each item is given. In this screenshot we talk about the color-coded optode labels.

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These clips are intended to get your experiments up and running in no time. We touch on each item in turn, and give a brief explanation of their uses.

In the Cap Kit video we talk through the four different spring holder pressures.

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Our extensive Support Site contains information on how to use our solutions . We have helped hundreds of scientists before. Please know that our support is free, and we are always happy to help.

You can reach us at support@nirx.net or talk to your consultant - they will put you in touch with the right expert.

Why Use Physiological Sensors in fNIRS Experiments?

Explaining Variance

In fNIRS recordings, we primarily want to see the signal from the brain. In reality, we also measure non-evoked, systemic activity from the surrounding tissue too (Tachtsidis and Scholkmann, 2016). You can regress out this noise using data from short-channels and physiological sensors. These sensors might include HR, BR, Tonic/Phasic Skin Conductance, Blood Pressure, SpO2 amongst others.

Multi-Modality

Being able to simultaneously measure several global body parameters could enrich your research with more data. It enables you to asses novel mechanisms and concurrent phenomena. A mobile device would allow for naturalistic experiments in complex real-world environments.

Some examples could be: emotional arousal in response to presented stimulus (dos Santos et al 2021), orthostatic hypotension and falls (Mol et al, 2020), cardiac output and respiration (Anh et al, 2016), or concurrent muscle activation (Ortega et al, 2020).

Introducing NIRxWINGS

The NIRxWINGS module for peripheral physiology measurements extends the NIRSport2. Signal processing algorithms can be optimized for artefact rejection (von Lühmann et al, 2019). It enables new experiments and amplifies your datasets with additional biosignal inputs.

Wireless data transfer allows the participant to move freely. Although the device stores data onboard, it also wirelessly streams for real-time display.

Mobililty

With NIRxWINGS, you are able to move outside the lab to conduct systemic physiology augmented fNIRS (SPA-fNIRS). You can access complex, dynamic and multi-sensory real-world environments.

Sensors

• Pulse oximetry (PPG)

• Heart-rate

• Heart-rate variability (HRV),

• Oxygen saturation (SpO2),

• Respiration,

• Temperature,

• Galvanic skin response (GSR),

• Bipolar signals such as EMG and ECG.

The physiology data from NIRxWINGS coupled with short-channels and motion sensors are highly effective in explaining the error variance in your fNIRS signal.

Check out this page to find more NIRxWINGS features.

Want to know more about this product? Send us an e-mail at support@nirx.net

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References:

Tachtsidis, I., & Scholkmann, F. (2016). False positives and false negatives in functional near-infrared spectroscopy: issues, challenges, and the way forward. Neurophotonics, 3(3), 031405. https://doi.org/10.1117/1.NPh.3.3.031405

**Technical References:**

von Lühmann, A., Boukouvalas, Z., Müller, K. R., & Adalı, T. (2019). A new blind source separation framework for signal analysis and artifact rejection in functional near-infrared spectroscopy. NeuroImage, 200, 72-88. https://doi.org/10.1016/j.neuroimage.2019.06.021

von Lühmann, A., Li, X., Gilmore, N., Boas, D. A., & Yücel, M. A. (2020). Open Access Multimodal fNIRS Resting State Dataset With and Without Synthetic Hemodynamic Responses. Frontiers in Neuroscience, 14. https://doi.org/10.3389/fnins.2020.579353

**Use Cases**

Useful to identify user attention, stress, and vigilance, to detect and differentiate evoked systemic physiology in fNIRs.

Ahn, S., Nguyen, T., Jang, H., Kim, J. G., & Jun, S. C. (2016). Exploring neuro-physiological correlates of drivers' mental fatigue caused by sleep deprivation using simultaneous EEG, ECG, and fNIRS data. Frontiers in human neuroscience, 10, 219. https://doi.org/10.3389/fnhum.2016.00219

Ortega, P., Zhao, T., & Faisal, A. A. (2020). HYGRIP: Full-Stack Characterization of Neurobehavioral Signals (fNIRS, EEG, EMG, Force, and Breathing) During a Bimanual Grip Force Control Task. Frontiers in Neuroscience, 14. https://doi.org/10.3389/fnins.2020.00919

Mol, A., Maier, A. B., van Wezel, R. J., & Meskers, C. G. (2020). Multimodal monitoring of cardiovascular responses to postural changes. Frontiers in physiology, 11, 168. https://doi.org/10.3389/fphys.2020.00168

dos Santos, F. R., Bazán, P. R., Balardin, J. B., de Aratanha, M. A., Rodrigues, M., Lacerda, S., ... & Kozasa, E. H. (2021). Changes in Prefrontal fNIRS Activation and Heart Rate Variability During Self-Compassionate Thinking Related to Stressful Memories. Mindfulness, 1-13. https://doi.org/10.1007/s12671-021-01789-0