We calculate the interhemispheric transfer time by giving visual stimuli (word) and sometimes, the data appear like this in some participants in some electrodes. Does anyone know the most likely reason for the opposite direction in our data? For example, the lateralized stimuli were given from the left visual area, but the transfer direction was from left to right at the occipital site.
Does the effect cross if the presentation side is switched? Is it only some subjects, and is it consistent for them? Does it work the same if you try with fNiS (infrared)?
The visual fields normally overlap, and possibly this overlap is not a constant for all people. Also, some people are left dominant and others are right dominant, and for some people this can/might be unrelated to handedness.
Thank you for your comments.
The subjects were all right handed, the situation was independent of the direction of presentation and not constant.
We did not try fNIRS.
Thus, I thought the most likely explanation would be individual differences in retinal fibres. However this measurement is a common and valid method. The lack of discussion in the papers made me sceptical.
Hazal Artuvan Korkmaz I agree the individual differences could be an explanation. The lack of discussion in the papers might be that the phenomena are either included in the variance or maybe excluded as outliers. If so we will not know how common it is. One question could be if it affects task performance (if you correct for possible reversal of the presentation).
Christer Johansson thanks a lot.
The inverse transitions I mentioned were sometimes between O1-2 and sometimes between P7-8 even in the same individual, and were independent of the stimulus location and stimulus type (word, pseudoword, etc.). Frankly, I also found it more reliable to consider them as outliers, but the number of remaining samples was almost half of the whole data! Therefore, I also think they cannot be outliers and the elimination may be biased. Thus, I wanted to open the issue for discussion here.
Hazal Artuvan Korkmaz There might be something to discover there. Many scientific discoveries have been in noticing something about outliers -- penicillin -- thousands of Petri Dishes must have been contaminated and discarded before someone noticed what was important.
I completely agree with you, Christer Johansson. Thank you very much for your contribution to the discussion.
What's your subjects' L1? Wei et al. 2023 find less lateralized language networks in L1 speakers of Arabic. Nor sure how consistent this is between speakers, maybe this helps:
Wei, X., Adamson, H., Schwendemann, M., Goucha, T., Friederici, A. D., & Anwander, A. (2023). Native language differences in the structural connectome of the human brain. Neuroimage, 270, 119955.
Thanks for your reply, L1 was Turkish in the experiment. Turkish has a Latin alphabet and is read from left to right like English. So, we did not think that the observation is caused by this item. Anna Shadrova
I don't think the authors attribute the divergent patterns to reading direction but to differences in the connectedness of syntactic vs. phonological networks in Arabic vs. German. Turkish might rely less on long-distance dependencies and vowel harmony may contribute to more phon. awareness . You'd know better, but i think there may be something to discover
Anna Shadrova You're right. Thank you very much for your valuable contributions.
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts