Advantages

The use of optical fiber based optodes for combining fNIRS with fMRI serves impactful research applications, and combining the two modalities aids the validation of the complementary signals (see Scarapicchia et al., 2017 for review). Compared to the deoxy-Hb based signal of fMRI, fNIRS separately measures deoxy-Hb and oxy-Hb which provides further information about hemodynamics and can improve the fMRI signal quality (Cooper et al., 2012). Additionally, combined fNIRS-fMRI multimodal imaging studies can assess the congruence between full-body behaviors with fNIRS and analogous stationery designs with fMRI, thereby extending research into more ecologically valid and real world settings.

Functionalities

NIRxBorealis performs dual-wavelength continuous-wave fNIRS on large tissue structures at high (several Hz) sampling rates in a time-multiplexed, scanning fashion. The use of powerful laser sources and ultra-sensitive Avalanche Photodiode detectors allows for diffuse transmission measurements up to ~4 cm, making it suitable for optical tomographic (‘multi-distance’) imaging which extends the depth of recording. A sliding rack enclosure couples with the NIRSport2 devices streamlining the installation. Source and detector components are implemented as modular electronic cards, which can be extended for higher density recording. The device also features eight parallel optically isolated digital input channels for the acquisition of event trigger signals. Operation is provided through our highly user-friendly Aurora fNIRS software, and connected via USB. This research platform uses our proprietary ultra-fast set up sequence and signal optimization process.

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FAQ

What is the NIRxBorealis used for?

The NIRxBorealis is designed specifically for simultaneous fNIRS and fMRI data acquisition. It uses optical fiber-based optodes that are MRI-compatible, allowing researchers to collect complementary neuroimaging data in a single session for richer, more validated results.

Why combine fNIRS with fMRI?

Combining the two modalities provides complementary information: fMRI captures deoxy-Hb-based BOLD signals with high spatial resolution, while fNIRS separately measures both oxy-Hb and deoxy-Hb, providing additional hemodynamic detail and helping to improve fMRI signal quality through physiological noise regression.

Are the optodes safe for use inside an MRI scanner?

Yes. The NIRxBorealis uses fiber optic-based optodes that contain no electronics or ferromagnetic materials, making them fully MRI-compatible. The recording hardware remains outside the scanner bore, connected via optical fiber bundles.

What cortical regions can be measured?

The NIRxBorealis supports flexible probe placement, allowing coverage of frontal, parietal, temporal, and occipital cortical regions. Custom cap configurations are available to suit specific experimental protocols and head sizes.

Does the system synchronize with the MRI scanner?

Yes. The NIRxBorealis includes synchronization inputs to align fNIRS recordings with MRI trigger signals, ensuring temporally matched datasets for concurrent analysis of both imaging modalities.