Do priors reshape motor preparation before you act?
In 62 adults, probabilistic cues biased decisions and inhibited prior-incongruent motor cortex excitability; MEP modulators vs non-modulators tracked believer vs empiricist styles.
Source
Preparing to act follows Bayesian inference rules
What they did
Participants did an RDM discrimination task with informative/uninformative cues while bilateral M1 TMS elicited MEPs at multiple peri-stimulus times.
What they found
Cues shifted decision criterion; prior expectations inhibited motor regions coding incongruent responses; trial-by-trial MEPs related to bias; schizotypal/autistic traits linked to believer/empiricist styles.
The limits
What it doesn't show
Not a clinical treatment study; styles are correlational with traits, not diagnostic categories.
Key terms
- Prior expectations
- Probabilistic beliefs about upcoming stimulus identity.
- MEP
- Motor-evoked potential from TMS over M1.
- CSE
- Corticospinal excitability indexed by MEP amplitude.
- RDM task
- Random-dot motion left/right discrimination.
- Believers’ style
- Predictive style relying heavily on priors.
- Empiricists’ style
- Predictive style downplaying priors.
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Sample size:
Common questions
N?
62 (37 female, ages 18–32).
Motor mechanism favored?
Inhibition of prior-incongruent motor cortex.
Styles?
Believers vs empiricists linked to schizotypal/autistic traits.
Task?
Cued random-dot motion discrimination.
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