Inhibiting the right dorsolateral prefrontal cortex selectively enhances unsupervised statistical learning

Authors: Pesthy, O., Pesthy, Z. V., Vekony, T., Janacsek, K., Fabo, D., Nemeth, D. Date: 2026-04-01 Paper ID: biorxiv:10.1101/2025.08.08.669288

Summary

This study investigates the causal role of the dorsolateral prefrontal cortex (DLPFC) in modulating unsupervised statistical learning using inhibitory repetitive transcranial magnetic stimulation (rTMS). Results show that inhibition of the right and bilateral DLPFC leads to enhanced statistical learning performance, whereas left DLPFC inhibition shows no effect. Contrary to previous theories, these effects appear independent of episodic memory systems, suggesting the right DLPFC normally acts to constrain statistical learning. The authors propose that the right DLPFC supports top-down control by limiting exploratory sampling, and its inhibition promotes a more flexible, exploratory processing style.

Key Contributions

• Demonstrated that inhibitory rTMS to the right and bilateral DLPFC significantly enhances unsupervised statistical learning performance.
• Provided evidence that the DLPFC’s role in statistical learning is hemisphere-dependent rather than a general prefrontal executive function.
• Found that reaction time variability increases following right DLPFC inhibition, suggesting a shift toward exploratory information-sampling strategies.
• Disproved the hypothesis that statistical learning and episodic memory compete via a direct gating mechanism by showing no impact of stimulation on episodic memory tasks.

Limitations

The study used a specific probabilistic sequence learning task; the findings may not generalize to other forms of statistical learning or long-term consolidation. Additionally, the mechanism of increased reaction time variability as an index of exploration remains a behavioral inference rather than a direct neural measurement.

Open Questions & Future Work

• dlpfc-statistical-learning-mechanism

Key Concepts

• right-dlpfc-statistical-learning-suppression: The right dorsolateral prefrontal cortex exerts a suppressive influence on unsupervised statistical learning, which can be enhanced by inhibitory stimulation.

Archivist Review

I have approved the core concept of right-lateralized DLPFC suppression and the associated open question regarding its specific cognitive mechanism. These represent significant findings regarding hemispheric cognitive control that are central to the paper’s contribution and likely to influence future neuromodulation research in neuroscience. Other candidates were deemed unnecessary as the primary findings are captured by these two entries.

Approved Concepts

• Right-lateralized DLPFC suppression of unsupervised learning: Establishes a causal link between right DLPFC activity and the gating of statistical learning, challenging prevailing models of prefrontal control.

Approved Open Questions

• DLPFC role in statistical learning: Understanding this mechanism is essential for clarifying how prefrontal circuits orchestrate the balance between automatic learning and flexible cognitive control, and whether this influence is mediated by attentional or exploration-specific neural circuits.

Links

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