F1 = [21:31]Hz, F2 = F1 +/- 2Hz. â Context-setting phases. 0. 50. 100. Exp 1. Exp 2. Mean accuracy (%. ) 0. 5. 10. 15. 20. 25. Exp 1. Exp 2. Senso ry precision Ï.
Atypical prior construction and adjustment in autism: Evidence from a tactile discrimination task
Laurie-Anne Sapey-Triomphe1, Sandrine Sonié1,2,3, Jérémie Mattout1, Christina Schmitz1 1. Lyon Neuroscience Research Centre, Brain dynamics and Cognition team, Université de Lyon, Lyon, France. 2. Centre de Ressource Autisme Rhône-Alpes, Centre Hospitalier Le Vinatier, Bron, France. 3. Hôpital Saint-Jean-de-Dieu, Lyon, France.
Introduction Probability density
● Perception results from the interplay between incoming sensory information and prior knowledge.
100
● In Autism Spectrum Disorders (ASD), it was suggested that many atypical behaviors could emerge from difficulties to build up and adapt priors1-5. As compared to neurotypicals (NT), they were hypothesized to have: - Hypo-priors (low precision of priors) 1 - High sensory precision 2 - High and inflexible precision of the prediction error (HIPPEA hypothesis) 3
Posterior
50
Prior
Likelihood
0
Prediction error
⪧ How do individuals with ASD learn and adjust their priors?
Stimulus feature
Methods ● Experimental design and time-order effect: 1st
● Experiment 1: Stable context
2nd
stimulation F2 = F1 +/- 2Hz
stimulation F1
- + 500ms
2000ms
Participants: 17 NT adults 16 ASD adults
Was F2 higher or lower than F1?
500ms
F1 F2
Fmean
Participants: 20 NT adults 17 ASD adults
F2>F1 ⇨ Easier: better & faster
F2 F1
Prior Fmean
Context setting at 30Hz F1 = 30Hz, F2 = [22:38]Hz
TOE assessment at 26Hz F1 = [21:31]Hz, F2 = F1 +/- 2Hz
● Computational model We used a perceptual decision model to investigate the evolution of the prior mean frequency in each group. Model parameters: input frequencies F1 and F2, sensory precision πS, prior mean frequency, 𝜋𝑝𝑟𝑖𝑜𝑟 𝜸: TOE parameter, function of
F2
F1
TOE assessment at 30Hz F1 = [25:35]Hz, F2 = F1 +/- 2Hz
● Experiment 2: Changing context
Can elicit a time-order effect, reflecting the effect of priors: Prior
Context setting at 30Hz F1 = 30Hz, F2 = [22:38]Hz
F2F1 F2F1 F2F1 F2F1 F2
