Perceptual precision of passive body tilt is consistent with statistically optimal cue integration.
When making perceptual decisions, humans have been shown to optimally integrate independent noisy multisensory information, matching maximum-likelihood (ML) limits. Such ML estimators provide a theoretic limit to perceptual precision (i.e., minimal thresholds). However, how the brain combines two interacting (i.e., not independent) sensory cues remains an open question. To study the precision achieved when combining interacting sensory signals, we measured perceptual roll tilt and roll rotation thresholds between 0 and 5 Hz in six normal human subjects. Primary results show that roll tilt thresholds between 0.2 and 0.5 Hz were significantly lower than predicted by a ML estimator that includes only vestibular contributions that do not interact. In this paper, we show how other cues (e.g., somatosensation) and an internal representation of sensory and body dynamics might independently contribute to the observed performance enhancement. In short, a Kalman filter was combined with an ML estimator to match human performance, whereas the potential contribution of nonvestibular cues was assessed using published bilateral loss patient data. Our results show that a Kalman filter model including previously proven canal-otolith interactions alone (without nonvestibular cues) can explain the observed performance enhancements as can a model that includes nonvestibular contributions.NEW & NOTEWORTHYWe found that human whole body self-motion direction-recognition thresholds measured during dynamic roll tilts were significantly lower than those predicted by a conventional maximum-likelihood weighting of the roll angular velocity and quasistatic roll tilt cues. Here, we show that two models can each match this "apparent" better-than-optimal performance:1) inclusion of a somatosensory contribution and2) inclusion of a dynamic sensory interaction between canal and otolith cues via a Kalman filter model.
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; koeunlim@mit.edu.|Program in Speech and Hearing Biosciences and Technology, Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Boston, Massachusetts; and.
Koeun
K
Lim
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.|Otology and Laryngology, Harvard Medical School, Boston, Massachusetts.
Faisal
F
Karmali
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.|Otology and Laryngology, Harvard Medical School, Boston, Massachusetts.
Keyvan
K
Nicoucar
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.|Otology and Laryngology, Harvard Medical School, Boston, Massachusetts.
Daniel M
DM
Merfeld
D000328:Adult; D001828:Body Image; D003463:Cues; D005260:Female; D006801:Humans; D065812:Interoception; D008297:Male; D008875:Middle Aged; D004856:Postural Balance; D011187:Posture; D014722:Vestibule, Labyrinth / Q000502:physiology
multisensory integration; otolith organs; semicircular canals; vestibular