Near infrared signal

1

Hello!
I saw an option in BS for NIRS maps, I'm wondering if is it possible to analyze near infrared spectroscopy signals?

and I'd like to ask if there is and example or real dataset from these signals

Thanks in advance!

2

Hello @tourette95,
You can find a tutorial here : https://neuroimage.usc.edu/brainstorm/Tutorials/NIRSFingerTapping . It is using a plug-in for Brainstorm called Nirstorm that is made to analyze NIRS signal.

You can also find information on our GitHub (Home · Nirstorm/nirstorm Wiki · GitHub).
Don't hesitate if you have any questions regarding Nirs analysis :slight_smile:

Best,
Edouard

3

Thank you so much!!

4

Hi again!
Thanks for being so kind,
I have a doubt:

I was reading about fNIRS but dont understand (yet) the advantages and drawback for this technique, comparing with EEG

Has the fNIRS equal, less or more temporal resolution than EEG? are the signals similar?

Is it the fNIR signal suitable for live and fast events (tasks)?

is it possible to get event related potentials with fNIR signal?

Thanks in advance!

5

Hi.

So fNIRS and egg are measuring different thing. On one side, eeg is measuring the electrical activity of the brain; when, fNIRS is like fMRI and is measuring the hemodynamic response of the brain.

The temporal resolution of fNIRS is around 10hz. So it's slower than egg but the phenomenon that are studied are also slower : the typical eeg response to a stimulus takes milliseconds when the hemodynamic response is much slower (peak around 5~6s after the stimulus). hs : for me, the main interesting thing is to combine eeg and nirs to have access to both information like you would do in eeg/fmri but with a better temporal resolution than in fMRI.

Is it the fNIR signal suitable for live and fast events (tasks)?
is it possible to get event related potentials with fNIR signal?

yes, like you would do in fMRI study.

I was reading about fNIRS but dont understand (yet) the advantages and drawback for this technique, comparing with EEG

You can have a look at theses paper :

Best regards,
Edouard

1 Like
6

Thanks a Lot!!!!

just one more question:

EEG signal units : μV

NIR signal:??? what kind of units does it has?

Thanks!

7

Hi again!
:D!
I was reading the NIR finger tapping tutorial for brainstorm
but I saw that the nir signal has also negative values (similar to eeg voltage),
how is it possible?

Bold signal has no negative values right? (unless ICA analysis where performed)
what does it mean?

and what unitis has this signal?

Thanks in advance

(sorry for the english :()

8

The NIRS tutorial on the Brainstorm is not meant to be an introduction to fNIRS.
If you are interested by this technique, you should start by reading the articles suggested by Edouard, and probably some general introduction to the technique - Google will be your best help.
Please get back to us if you have specific questions about how to handle fNIRS recordings in Brainstorm.