9/ Big thanks to our supporting institutions:
@umontreal.ca / @facmed-umontreal.bsky.social, @chusaintejustine.bsky.social / @cra-chusj.bsky.social, @braincanada.bsky.social, @simonsfoundation.org, @azrielifoundation.bsky.social, @ivado.bsky.social, @mila-quebec.bsky.social, UNIQUE, FRQS & NSERC 🙏

8/ Grateful to all the participants who made this study possible, and to the incredible @ppsp-team.bsky.social.
Special thanks to @introspection.bsky.social for his guidance.
Proud to share first authorship with @quentinmoreau.bsky.social, and to collaborate with L. Moses & G. Milanova.

7/ In short:

❌ No effect on motor coordination (Exp1 & 2)

✅⏳ Cumulative effects on social inference (cooperativeness & humanness) with repeated stimulation (Exp1)

❌ No effect on social inference when HD-tRNS/sham trials were intermixed (Exp2)

6/ In Exp1, HD-tRNS also progressively reduced humanness attribution during competitive interactions.

This effect was strongest in participants who already viewed the VP as less human, suggesting a possible ceiling effect of modulation.

5/ First, HD-tRNS had no effect on motor coordination in either experiment, suggesting rTPJ stimulation doesn’t modulate low-level synchrony.

But in Exp1, it progressively sharpened detection of the VP's competitive intent, with participants attributing less cooperativeness over trials.

4/ Two complementary experiments:
Exp1 (n=39): HD-tRNS⚡ or sham 🚫 in randomized blocks
Exp2 (n=40): HD-tRNS⚡ and sham 🚫 in randomized trials

During trials, participants synchronized finger movements with a covert VP, then rated perceived cooperativeness & humanness (👱 vs 🤖).

3/ In our study, we applied HD-tRNS over the rTPJ as participants interacted with the HDC, aiming to provide further evidence of the rTPJ’s causal role in real-time social interaction.

2/ Our work directly builds on Dumas et al. (2020), who combined high-density EEG with the Human Dynamic Clamp (HDC) paradigm to reveal the rTPJ as a key cortical hub for integrating self–other representations.

1/ TL;DR: Brief online high-definition transcranial random noise stimulation (HD-tRNS🎯⚡) over the right temporoparietal junction (rTPJ🧠) sharpened detection of competitive intent during interaction with a covert virtual partner (VP🤖)—without affecting motor synchrony.

Our latest work at @ppsp_team is now available on @biorxivpreprint.bsky.social

⚡🧠~🤖 We tested whether online non-invasive brain stimulation could modulate real-time human~machine social interactions.

📄 Read the preprint: www.biorxiv.org/content/10.1...

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