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Mind and Body => Neuroscience => Topic started by: Chip on May 28, 2019, 07:23:22 PM

Title: Concurrent fNIRS (functional Near Infra Red Scans) and EEG
Post by: Chip on May 28, 2019, 07:23:22 PM

source: https://nirx.net/fnirs-eeg

an excerpt ot two:

Quote

A local increase in cortical blood flow accompanies almost all neuronal responses to stimulus in the brain. This relationship, termed neurovascular coupling, involves many steps from the initial firing of the neurons, to release of chemical transmitters, to the final vasoconstriction or vasodilatation. Understanding this relationship between brain activity and the resulting changes in metabolism and blood flow remains a vital research area.

EEG and fNIRS capture different events in this cascade, but are both linked to the same neural activity. The combination of these two methodologies offers the possibility to examine cortical activity more comprehensively. EEG and fNIRS have very different but complementary temporal and spatial resolution: while Evoked Potentials (EPs) detect the cortical response to a given stimulus with high temporal resolution, fNIRS localizes changes in oxygen metabolism that follow neural activation.

Data Synchronization
 
As fNIRS and EEG measurements are recorded independently, it is important for simultaneous trigger synchronization with both data streams. This precisely marks the data of interest for online and offline analysis. A precise synchronization can be easily achieved with the NIRx Parallel Port Replicator, which powers the incoming signal via USB and splits a single DB-25 (parallel port) input to four or more outputs. A general schematic of stimulus presentation and synchronization of fNIRS and EEG measures is depicted to the right below.

(https://static1.squarespace.com/static/54e7b27de4b0b080e1552803/t/5a95b9cfe2c483bf96b7281e/1522696826327/EEG+6.PNG?format=750w)

... continues at the source link