2021 SfNIRS Virtual Meeting Q&A: Oral session – topic 4 (fNIRS in social and cognitive neuroscience)

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Talukdar Raian Ferdous
Talukdar Raian Ferdous (@talukdarraianferdous)
6 days ago
Prefrontal cortical activation associated with prospective memory while walking around a real world street environment" Read more »

How was the signal quality? What were the challenges in the data collection stage of this walking around task?

Ilias Tachtsidis
Ilias Tachtsidis (@i-tachtsidisucl-ac-uk)
6 days ago
Does mother-child neural synchrony go beyond synchrony in arousal and behavior? Findings from fNIRS-ECG hyperscanning" Read more »

Vanessa an excellent talk and very clear and innovative processing methods. (1) Have you tried to mix up the pairs to see if your effects are still hold up; (2) Once in the graph domain i am wondering if there could me more descriptive markers that you could use beyond the density of the graph?

ReindlVanessa
ReindlVanessa (@reindlvanessa)
Reply to  Ilias Tachtsidis
6 days ago

Thank you for your questions, Ilias!

(1) We have calculated the wavelet coherence for all possible combinations of independent mother/stranger – child dyads (“shuffled pairs”) while holding the condition and channel combination fixed. Using this block-wise permutation, we have derived “shuffled-pair” distributions individually for each condition and channel-combination (edge) and then used these distributions to reduce the graphs. Since the threshold was set to the 95% quantile, shuffled pairs had a mean density of 5% in each condition. We further tested whether global density of actual pairs was higher, which was the case only for mother-child competition.

(2) In our analysis we have focused on global and nodal inter-brain density to gain both global and local insights into the brain regions which drive interpersonal neural synchrony. We used density instead of degree to account for bad channels. An additional global metric which is sometimes used in the EEG hyperscanning literature is divisibility. However, not all metrics from intra-brain networks can be meaningfully applied to inter-brain networks.

Ilias Tachtsidis
Ilias Tachtsidis (@i-tachtsidisucl-ac-uk)
6 days ago
Modulation of Temporoparietal Junction Activity by fNIRS-based Neurofeedback" Read more »

Hi Simon, i hope you feel better. I am interesting to know more about your FB_activation signal; how you decide that metric? and what physiological does represent?

Simon Kohl
Simon Kohl (@simonhkohl)
Reply to  Ilias Tachtsidis
6 days ago

Hi Ilias, yes I am already feeling better. Thanks!
We used HbO data of one single channel placed over the right TPJ. We chose HbO since the signal has a larger amplitude. However, HHb on the other hand is less noisy and can be used for neurofeedback applications as well. The signal was preprocessed using a band-pass filer of 0.01-1Hz as well as a moving average of 5s. Further, we applied the correlation-based signal improvment (Cui et al., 2010) for online correction of motion artifacts.
The feedback signal was standardized by subtracting the the Median of the 5s baseline period before each trial and dividing it by the standard deviation of the baseline period. So the feedback signal is measuring changes in SD compared to baseline.

Ilias Tachtsidis
Ilias Tachtsidis (@i-tachtsidisucl-ac-uk)
6 days ago
A Neural Complex for Emotion-Contagion: An fNIRS Hyperscanning Investigation" Read more »

Joy would it be worth to do an experiment that the video watcher tries to simulate\copy the faces of the happy, creepy and neutral rather than watching the relevant pictures and experiencing the emotions? Within that approach you can show to the movie watcher other types of “happy looking faces” for them to copy some clearly happy and others less; so its not real emotion that makes the movie watcher to make a face!!