Rogue Resolutions launches Brainsight NIRS

NIRS (Near Infrared Spectroscopy) is a form of imaging that can capture brain function (functional brain imaging). NIRS uses infrared light that is delivered through optical fibres to the scalp and then through the skull and into the brain, once at the brain this infrared light reflects and scatters off the brain tissue and blood. This modification of absorption that results in changes in the concentrations of oxy and de-oxy haemoglobin in the blood. These changes in oxy and de-oxy haemoglobin are recorded using a secondary set of optical fibres, on the scalp, that capture the same infrared light as it exits the head.   Using principles developed for functional Magnetic Resonance Imaging (fMRI) it has been established that these changes in blood oxygenation are directly correlated to alterations in brain activity. These source and detector fibres or optodes (an optical analog to commonly used EEG electrodes) are positioned on the head in an array. These array positions on the head can then be recorded using a neuronavigation system and the variations in blood oxygenation levels can be measured and mapped to small regions of the subjects brain and be represented as 3D activation maps on the reconstructed brain. Brainsight NIRS effortlessly combines NIRS imaging and neuronavigation to provide a unique and powerful solution for functional brain imaging in neuroscience.   Some of the main features of Brainsight NIRS are:  

• Unique optode and cap design to optimize multi-modality use, including:
  NIRS & tDCS
  NIRS & TMS
  NIRS & EEG
  NIRS & TMS & EEG
  NIRS & MEG
• This innovative multi-modality approach will allow researchers to combine different brain imaging and brain stimulation techniques to maximize their experimental design and outcomes. Our patented optode and cap designs have been developed with specific attention being given to allow the combination of these modalities.

Many currently available NIRS systems were designed to be originally used as stand-alone devices and are therefore not optimized for this multi-modality approach, which imposes a number of physical constraints (e.g. optode design). For effective TMS experimentation it is a requirement that there is good TMS coil coupling with the subject head. Current optode design makes this difficult to achieve due to the design and size (height) of these optodes. Brainsight NIRS optode design utilizes low-profile optodes that are only 7mm in height and our cap design allows us to direct optical fibres close to the scalp and away from the optode giving us a very low profile of optode and fibre therefore maximizing the potential for coil coupling. This low profile optode design also makes Brainsight NIRS ideal for use within the compact operating environment of MEG also. The unique Brainsight NIRS optode cap also allows for the interleaving of tDCS electrodes, making it suitable for simultaneous NIRS and tDCS. When combined with a suitable TMS / tDCS / tACS compatible EEG system (NEURO PRAX TMS/tES EEG) simultaneous TMS / tES, EEG and NIRS can be achieved.   High frequency sampling and analog signals for biosignal and stimulus recording.   The system supports 100Hz sampling of the NIRS and includes 8 analog channels to simultaneously record the stimulus and bio-signals (e.g. pulse-ox, breathing) alongside the NIRS signals.

Unique dedicated Scalp Activity Detectors

Signals recorded at a detector optode will include light scattered within the brain but will also include light scattered by the scalp. Some of the infrared light delivered by the source optode can be reflected off the scalp and skull and be picked up by the detector optode without ever entering brain tissue. The scalp and muscle tissue of the head also contain many blood vessels hence some of the signal will contain scatter from the blood within this and it is this scalp signal that can sometimes be correlated to the stimulus from subtle facial movements if the stimulus evokes facial movements as well as brain activation.   However a recent trend in NIRS is to measure the light scattered within the scalp from the source optode to the detector optode (without going into the brain) as a means of filtering the brain signals to account for this contamination.   This scalp activation can be measured by re-assigning detectors to measure scalp signals by placing them closer to the source, so the light measured is predominantly from the scalp, where wider source-detector spacing measures predominantly (but not completely) cortical activation. This works well, however it means sacrificing detectors that could be used to measure brain activation for scalp measurement.   Brainsight NIRS blocks comprise of 4 sources (each source can have 2 or 3 wavelengths), 8 cortical detectors and 4 scalp detectors. Each scalp detector is placed close to a source so the signal component from the scalp is measured while allowing all the original detectors to be used for the scalp. This may seem arbitrary, however since the scalp activation signal is orders of magnitude stronger than the cortical signals, these dedicated scalp detector channels can be designed using less expensive components without loss of signal quality. This also means that users do not have to sacrifice any recording channels for this scalp detection activity, meaning a 32 channel system is a truly 32 channel device.  

Modular by design   

Brainsight NIRS has been designed to allow for easy upgrade. All device main platforms are 32-channel ready, however individual blocks of 8-channels can be purchased and upgraded as and when required to a maximum of 32-channels.   The main platform, where data is digitized and stored and where the electronics are located, has been designed to be 32-channel ready. However all the optical components (the expensive parts) are contained within the removable 8-channel blocks. This means that Brainsight NIRS can be purchased with fewer optodes, to reduce the initial investment, and then upgraded as funds and requirements allow with the purchase of further 8-channel blocks.   Flexible by design.   NIRS is an evolving science; the most commonly used configuration is to use two infrared wavelengths per fibre to measure the blood oxygenation. However there is a recent move towards different wavelengths or the use of three wavelengths per channel.   Brainsight NIRS has been optimized to allow users to easily upgrade to a three-wavelength system simply by purchasing new channel blocks and source optode fibres (that combine the three sources into a single source optode). The rest of the system will remain unchanged, saving money and offering maximum flexibility to meet differing research demands and needs.  

Familiar user interface     

If you have used Brainsight 2, you’re ready to use Brainsight NIRS, which takes advantage of using the same easy to understand, workflow based user interface developed and implemented in Brainsight 2 neuronavigation systems.   The Brainsight computer is connected to the NIRS platform via Ethernet meaning the control computer can be as near or as far from the NIRS device as is necessary. In many NIRS applications, it is required to have the NIRS in a dark room shielded from outside stimuli; in this situation the Brainisght computer can easily be placed outside the dark room via wired or wireless Ethernet.   In the future, other mobile devices can be used to configure and monitor the NIRS experiment as well as via the Brainsight computer.   For further information on system specification and pricing please contact us.