EEG-NIRS Experimental Design

EEG-NIRS Experimental Design - Decision Making

Friday, 21 de February de 2020

EEG-NIRS Experimental Design - Decision Making

Check the neural substrates of decision making in visual attention

The visual system is one of the main senses that contributes to managing and situating us daily, as well as detecting information about what surrounds us. We are daily engaged in visual search and choosing a specific object that will then be processed at the expense of others within the same scenario. In addition, our survival throughout evolution has depended, and still depends to some degree, on our interpretation of objects in space whether or not they are in motion.

Therefore, the more we know about this system, the more we get information to build tools and techniques to improve learning and / or treat people with impairment in some stage of attention and decision in the visual system. For this, the EEG and fNIRS tools will be used in this experimental design while the subjects perform decision-making tasks related to visual attention. Occipital lobe regions, more specifically V1 (more primary visual processing) and V4 (more complex visual processing), will be analyzed in the prefrontal involved with selective attention and visual decision making and the parietal region underlying voluntary attention.

In view of this, an experimental design was developed that encompasses the processes mentioned above. The subjects' neuronal activity will be recorded through EEG and NIRS at the beginning of the task, throughout the task and 2 min after the task. The activity recorded before and after the task will be used as a baseline.

Experimental Design:

Trial A

1 - Screen with two figures of different shape and colors (Ex: an orange ball and a gray triangle) lasting x seconds.

2 - 20 second interval (dark screen)

3 - Screen with a figure that appeared previously and another with a different shape and color (orange ball and a blue square) lasting for x seconds.

4 - 15 second interval (dark screen)

5 - Screen with a figure that appeared in the previous two frames and another figure that appeared only once with a question asking to click which of the two objects appeared twice.

Trial B

Repeat the above process, but at the end, ask the subject to click on the object that did NOT appear twice.

Present approximately a total of 50 to 100 trials A and B in a random manner, varying the figures over time. In this way, the subjects will be their own controls.

Parameters that can be analyzed and grouped: correct and incorrect response and response latency. The record periods to be analyzed are 600 ms before the individual presses the click until 200 ms after pressing the click. This period should also be compared with baseline activity.

Response parameters:

In the EEG:

Analyze waves in each region in the correct attempts
Analyze waves in each region in the wrong attempts
Correlate the waves in each region with correct answers
Correlate waves from each region with incorrect answers
Check synchrony / coherence between each region in the correct attempts
Check synchrony / coherence between each region in the wrong attempts

  In fNIRS:

Analyze hemodynamic response in each region in the correct attempts
Analyze hemodynamic response in each region in the failed attempts
Correlate hemodynamic response in each region with correct responses
Correlate hemodynamic response of each region with incorrect answers

   Both:

Correlate EEG electrophysiological activity with fNIRS hemodynamic response in each region in the correct responses.
  Correlate EEG electrophysiological activity with fNIRS hemodynamic response in each region in incorrect responses.

References

Desimone, R. and Duncan, J. (1995) Neural mechanisms of selective visual attention. Annu. Rev. Neurosci., 18: 193–222.

Squire R. F., Noudoost B., Schafer R. J., and Moore T. (2013) Prefrontal Contributions to Visual Selective Attention. Annu. Rev. Neurosci. 36:451– 66.

Erdogan G., Chen Q., Garcea F. E., Bradford Z. Mahon and Jacobs R. A. (2016) Multisensory Part-based Representations of Objects in Human Lateral Occipital Cortex. Journal of Cognitive Neuroscience. Volume 28 | Issue 6 | p.869-881.

Luck SJ, Chelazzi L, Hillyard SA, Desimone R. 1997. Neural mechanisms of spatial selective attention in areas V1, V2, and V4 of macaque visual cortex. J. Neurophysiol. 77:24–42

Manger P. R. (2005) Establishing order at the systems level in mammalian brain evolution. Brain Research Bulletin.

Moore, T., & Zirnsak, M. (2017). Neural Mechanisms of Selective Visual Attention. Annual Review of Psychology, 68, 47–72.

Tong W. et al. (2019) Improved visual acuity using a retinal implant and an optimized stimulation strategy. J Neural Eng. Oct 30. doi: 10.1088/1741-2552/ab529

Also See these other knowledge base:

Hardware:

NIRSport - NIRS

NIRScout - Our Most-Powerful NIRS Imager

Software:

Aurora fNIRS - NIRSport 2 Acquisition software. How acquire data with NIRS?

Experimental Design:

NIRS Experimental Design - Gait Initiation

Experimental Design Brands (NIRS)

fNIRS Experimental Design on Visual Cortex

Authors: Patrícia Pauli And César Noronha

The content published here is the exclusive responsibility of the authors.

Autor: