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Integration of Semi-Circular Canal and Otolith Cues for Direction Discrimination during Eccentric Rotations.

Soyka F, Bülthoff HH, Barnett-Cowan M - PLoS ONE (2015)

Bottom Line: Discrimination thresholds for eccentric rotations reduced with increasing radii, indicating that additional tangential accelerations (which increase with radius length) increased sensitivity.Our findings clearly show that information from the two organs is integrated.However the measured thresholds for 3 of the 5 eccentric rotations are even more sensitive than predictions from the optimal integration model suggesting additional non-vestibular sources of information may be involved.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Biological Cybernetics, Department: Human Perception, Cognition and Action, Tübingen, Germany.

ABSTRACT
Humans are capable of moving about the world in complex ways. Every time we move, our self-motion must be detected and interpreted by the central nervous system in order to make appropriate sequential movements and informed decisions. The vestibular labyrinth consists of two unique sensory organs the semi-circular canals and the otoliths that are specialized to detect rotation and translation of the head, respectively. While thresholds for pure rotational and translational self-motion are well understood surprisingly little research has investigated the relative role of each organ on thresholds for more complex motion. Eccentric (off-center) rotations during which the participant faces away from the center of rotation stimulate both organs and are thus well suited for investigating integration of rotational and translational sensory information. Ten participants completed a psychophysical direction discrimination task for pure head-centered rotations, translations and eccentric rotations with 5 different radii. Discrimination thresholds for eccentric rotations reduced with increasing radii, indicating that additional tangential accelerations (which increase with radius length) increased sensitivity. Two competing models were used to predict the eccentric thresholds based on the pure rotation and translation thresholds: one assuming that information from the two organs is integrated in an optimal fashion and another assuming that motion discrimination is solved solely by relying on the sensor which is most strongly stimulated. Our findings clearly show that information from the two organs is integrated. However the measured thresholds for 3 of the 5 eccentric rotations are even more sensitive than predictions from the optimal integration model suggesting additional non-vestibular sources of information may be involved.

No MeSH data available.


Related in: MedlinePlus

Model Results.Mean results for the eccentric discrimination thresholds together with standard errors are shown (blue). Model fits are shown in black for the switching model and in red for the integration model. It can be clearly seen that the integration model predicts the eccentric thresholds better, but 3 out of 5 thresholds are even significantly lower than what the optimal integration model predicts.
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pone.0136925.g005: Model Results.Mean results for the eccentric discrimination thresholds together with standard errors are shown (blue). Model fits are shown in black for the switching model and in red for the integration model. It can be clearly seen that the integration model predicts the eccentric thresholds better, but 3 out of 5 thresholds are even significantly lower than what the optimal integration model predicts.

Mentions: The predictions for the eccentric thresholds based on the integration and the switching model are shown together with the measurements in Fig 5. It can be seen that the integration model (red) better fits all the measurements (blue) than the switching model (black). However, it can also be seen that only 2 out of 5 of the measured thresholds are actually well predicted by the integration model. In order to quantify this, one-sample t-tests were performed testing if the measured threshold distribution at a given radius significantly differs from the integration model prediction for that radius. For r = 0.1, 0.3 and 0.5m we find significant differences p = .006, .002 and p < .001. Whereas for r = 0.2 and 0.8m there are no differences p = .78 and .53.


Integration of Semi-Circular Canal and Otolith Cues for Direction Discrimination during Eccentric Rotations.

Soyka F, Bülthoff HH, Barnett-Cowan M - PLoS ONE (2015)

Model Results.Mean results for the eccentric discrimination thresholds together with standard errors are shown (blue). Model fits are shown in black for the switching model and in red for the integration model. It can be clearly seen that the integration model predicts the eccentric thresholds better, but 3 out of 5 thresholds are even significantly lower than what the optimal integration model predicts.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555836&req=5

pone.0136925.g005: Model Results.Mean results for the eccentric discrimination thresholds together with standard errors are shown (blue). Model fits are shown in black for the switching model and in red for the integration model. It can be clearly seen that the integration model predicts the eccentric thresholds better, but 3 out of 5 thresholds are even significantly lower than what the optimal integration model predicts.
Mentions: The predictions for the eccentric thresholds based on the integration and the switching model are shown together with the measurements in Fig 5. It can be seen that the integration model (red) better fits all the measurements (blue) than the switching model (black). However, it can also be seen that only 2 out of 5 of the measured thresholds are actually well predicted by the integration model. In order to quantify this, one-sample t-tests were performed testing if the measured threshold distribution at a given radius significantly differs from the integration model prediction for that radius. For r = 0.1, 0.3 and 0.5m we find significant differences p = .006, .002 and p < .001. Whereas for r = 0.2 and 0.8m there are no differences p = .78 and .53.

Bottom Line: Discrimination thresholds for eccentric rotations reduced with increasing radii, indicating that additional tangential accelerations (which increase with radius length) increased sensitivity.Our findings clearly show that information from the two organs is integrated.However the measured thresholds for 3 of the 5 eccentric rotations are even more sensitive than predictions from the optimal integration model suggesting additional non-vestibular sources of information may be involved.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Biological Cybernetics, Department: Human Perception, Cognition and Action, Tübingen, Germany.

ABSTRACT
Humans are capable of moving about the world in complex ways. Every time we move, our self-motion must be detected and interpreted by the central nervous system in order to make appropriate sequential movements and informed decisions. The vestibular labyrinth consists of two unique sensory organs the semi-circular canals and the otoliths that are specialized to detect rotation and translation of the head, respectively. While thresholds for pure rotational and translational self-motion are well understood surprisingly little research has investigated the relative role of each organ on thresholds for more complex motion. Eccentric (off-center) rotations during which the participant faces away from the center of rotation stimulate both organs and are thus well suited for investigating integration of rotational and translational sensory information. Ten participants completed a psychophysical direction discrimination task for pure head-centered rotations, translations and eccentric rotations with 5 different radii. Discrimination thresholds for eccentric rotations reduced with increasing radii, indicating that additional tangential accelerations (which increase with radius length) increased sensitivity. Two competing models were used to predict the eccentric thresholds based on the pure rotation and translation thresholds: one assuming that information from the two organs is integrated in an optimal fashion and another assuming that motion discrimination is solved solely by relying on the sensor which is most strongly stimulated. Our findings clearly show that information from the two organs is integrated. However the measured thresholds for 3 of the 5 eccentric rotations are even more sensitive than predictions from the optimal integration model suggesting additional non-vestibular sources of information may be involved.

No MeSH data available.


Related in: MedlinePlus