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Poster Session A: Tuesday, August 12, 1:30 – 4:30 pm, de Brug & E‑Hall

Bayesian modeling reveals distinct priors for tactile and proprioceptive localization

Hüseyin Orkun Elmas¹, W. Pieter Medendorp, Luke E. Miller; ¹Donders Institute for Brain, Cognition and Behaviour

Presenter: Hüseyin Orkun Elmas

When a mosquito lands on your finger, swatting it requires your brain to calculate its location in the external space, which depends on the body’s 3D posture. Two competing computational hypotheses explain how the brain solves this challenge: the integration hypothesis, where tactile signals are transformed into spatial coordinates by integrating touch and posture information; and the cueing hypothesis, where touch merely cues a location on the body whose position is specified via proprioception. If touch merely triggers proprioceptive localization (cueing hypothesis), both localizing touch and body parts in space should rely on the same Bayesian computations, with identical prior expectations about the mosquito’s spatial location; if they involve different computational processes (integration hypothesis), the underlying priors might differ. Twenty-one participants localized their fingers via proprioception or touch in nine hand positions. We compared Bayesian model variants with different parameter sharing structures and quantified the overlap between these processes. Models allowing different prior distributions between modalities provided the best fit for most participants. The distances between fitted spatial priors showed 15 out of 19 participants had significantly different prior distributions across modalities. Our findings provide computational evidence that tactile localization involves different processes beyond those used in proprioceptive localization, providing evidence against the cueing hypothesis.

Topic Area: Predictive Processing & Cognitive Control

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