Brain–Computer Interface |
fNIRS has been successfully implemented as a control signal for brain–computer interface
systems.
|
Brain Mapping |
Brain mapping is a set of neuroscience techniques predicated on the mapping of
(biological)
quantities or properties onto spatial representations of the (human or non-human) brain
resulting in
maps.
|
Cerebral Oximetry |
NIRS monitoring is helpful in a number of ways. Preterm infants can be monitored
reducing
cerebral
hypoxia and hyperoxia with different patterns of activities. It is an effective aid in
Cardiopulmonary bypass, is strongly considered to improve patient outcomes and reduce
costs and
extended stays.There are inconclusive results for use of NIRS with patients with
traumatic brain
injury, so it has been concluded that it should remain a research tool. |
Diffuse Optical Tomography |
Diffuse optical tomography is the 3D version of Diffuse optical imaging. Diffuse optical
images
are
obtained using NIRS or fluorescence-based methods. These images can be used to develop a
3D
volumetric model which is known as the Diffuse Optical Tomography. |
fNIRS Cap |
fNIRS electrode locations can be defined using a variety of layouts, including names and
locations
that are specified by the International 10–20 system as well as other layouts that are
specifically
optimized to maintain a consistent 30mm distance between each location. In addition to
the
standard
positions of electrodes, short separation channels can be added. Short separation
channels allow
the
measurement of scalp signals. Since the short separation channels measure the signal
coming from
the
scalp, they allow the removal of the signal of superficial layers. This leaves behind
the actual
brain response. Short separation channel detectors are usually placed 8mm away from a
source.
They
do not need to be in a specific direction or in the same direction as a detector. |
Functional Connectivity |
fNIRS measurements can be used to calculate functional connectivity. Multi-channel fNIRS
measurements create a topographical map of neural activation, whereby temporal
correlation
between
spatially separated events can be analyzed. Functional connectivity is typically
assessed in
terms
correlations between the hemodynamic responses of spatially distinct regions of interest
(ROIs).
In
brain studies, functional connectivity measurements are commonly taken for resting state
patient
data, as well as data recorded over stimulus paradigms. The low cost, portability and
high
temporal
resolution of fNIRS, with respect to fMRI, have proven to be highly advantageous in
studies of
this
nature. |
Functional Neuroimaging |
The use of fNIRS as a functional neuroimaging method relies on the principle of
neuro-vascular
coupling also known as the haemodynamic response or blood-oxygen-level dependent (BOLD)
response.
This principle also forms the core of fMRI techniques. Through neuro-vascular coupling,
neuronal
activity is linked to related changes in localized cerebral blood flow. fNIRS and fMRI
are
sensitive
to similar physiologic changes and are often comparative methods. Studies relating fMRI
and
fNIRS
show highly correlated results in cognitive tasks. fNIRS has several advantages in cost
and
portability over fMRI, but cannot be used to measure cortical activity more than 4 cm
deep due
to
limitations in light emitter power and has more limited spatial resolution. fNIRS
includes the
use
of diffuse optical tomography (DOT/NIRDOT) for functional purposes. Multiplexing fNIRS
channels
can
allow 2D topographic functional maps of brain activity (e.g. with Hitachi ETG-4000,
Artinis
Oxymon,
NIRx NIRScout, etc.) while using multiple emitter spacings may be used to build 3D
tomographic
maps.
|
Hyperscanning |
Hyperscanning involves two or more brains monitored simultaneously to investigate
interpersonal
(across-brains) neural correlates in various social situations, which proves fNIRS to be
a
suitable
modality for investigating live brain-to-brain social interactions. |
Hypoxia and Altitude Studies |
With our constant need for oxygen, our body has developed multiple mechanisms that
detect oxygen
levels, which in turn can activate appropriate responses to counter hypoxia and generate
a
higher
oxygen supply. Moreover, understanding the physiological mechanism underlying the bodily
response to
oxygen deprivation is of major importance and NIRS devices have shown to be a great tool
in this
field of research. |
Music and the Brain |
fNIRS can be used to monitor musicians’ brain activity while playing musical
instruments. |
Virtual and Augmented Reality |
Modern fNIRS systems are combined with virtual or augmented reality in studies on
brain-computer
interfaces, neurorehabilitation or social perception. |
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