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Modeling direction discrimination thresholds for yaw rotations around an earth-vertical axis for arbitrary motion profiles.

Soyka F, Giordano PR, Barnett-Cowan M, Bülthoff HH - Exp Brain Res (2012)

Bottom Line: In accordance with previous research, thresholds decreased with shortening period length (from ~2 deg/s for 6.7 s to ~0.8 deg/s for 0.3 s).These measurements were used to fit a novel model based on a description of the firing rate of semi-circular canal neurons.In accordance with previous research, the estimates of the model parameters suggest that velocity storage does not influence perceptual thresholds.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Spemannstrasse 38, 72076 Tübingen, Germany. florian.soyka@tuebingen.mpg.de

ABSTRACT
Understanding the dynamics of vestibular perception is important, for example, for improving the realism of motion simulation and virtual reality environments or for diagnosing patients suffering from vestibular problems. Previous research has found a dependence of direction discrimination thresholds for rotational motions on the period length (inverse frequency) of a transient (single cycle) sinusoidal acceleration stimulus. However, self-motion is seldom purely sinusoidal, and up to now, no models have been proposed that take into account non-sinusoidal stimuli for rotational motions. In this work, the influence of both the period length and the specific time course of an inertial stimulus is investigated. Thresholds for three acceleration profile shapes (triangular, sinusoidal, and trapezoidal) were measured for three period lengths (0.3, 1.4, and 6.7 s) in ten participants. A two-alternative forced-choice discrimination task was used where participants had to judge if a yaw rotation around an earth-vertical axis was leftward or rightward. The peak velocity of the stimulus was varied, and the threshold was defined as the stimulus yielding 75 % correct answers. In accordance with previous research, thresholds decreased with shortening period length (from ~2 deg/s for 6.7 s to ~0.8 deg/s for 0.3 s). The peak velocity was the determining factor for discrimination: Different profiles with the same period length have similar velocity thresholds. These measurements were used to fit a novel model based on a description of the firing rate of semi-circular canal neurons. In accordance with previous research, the estimates of the model parameters suggest that velocity storage does not influence perceptual thresholds.

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Combined data set of Benson’s, Grabherr’s and the present data. The model fit lines represent the predictions for sinusoidal acceleration profiles 127 × 88 mm (300 × 300 DPI)
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Fig6: Combined data set of Benson’s, Grabherr’s and the present data. The model fit lines represent the predictions for sinusoidal acceleration profiles 127 × 88 mm (300 × 300 DPI)

Mentions: The best model fit to the combined data set, consisting of 30 data points, was calculated and the estimated model parameters are K = 2.04 s2/deg, , and (SEE = 8.633). The combined data set together with threshold predictions for sinusoidal accelerations from different models is shown in Fig. 6.Fig. 6


Modeling direction discrimination thresholds for yaw rotations around an earth-vertical axis for arbitrary motion profiles.

Soyka F, Giordano PR, Barnett-Cowan M, Bülthoff HH - Exp Brain Res (2012)

Combined data set of Benson’s, Grabherr’s and the present data. The model fit lines represent the predictions for sinusoidal acceleration profiles 127 × 88 mm (300 × 300 DPI)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375416&req=5

Fig6: Combined data set of Benson’s, Grabherr’s and the present data. The model fit lines represent the predictions for sinusoidal acceleration profiles 127 × 88 mm (300 × 300 DPI)
Mentions: The best model fit to the combined data set, consisting of 30 data points, was calculated and the estimated model parameters are K = 2.04 s2/deg, , and (SEE = 8.633). The combined data set together with threshold predictions for sinusoidal accelerations from different models is shown in Fig. 6.Fig. 6

Bottom Line: In accordance with previous research, thresholds decreased with shortening period length (from ~2 deg/s for 6.7 s to ~0.8 deg/s for 0.3 s).These measurements were used to fit a novel model based on a description of the firing rate of semi-circular canal neurons.In accordance with previous research, the estimates of the model parameters suggest that velocity storage does not influence perceptual thresholds.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Spemannstrasse 38, 72076 Tübingen, Germany. florian.soyka@tuebingen.mpg.de

ABSTRACT
Understanding the dynamics of vestibular perception is important, for example, for improving the realism of motion simulation and virtual reality environments or for diagnosing patients suffering from vestibular problems. Previous research has found a dependence of direction discrimination thresholds for rotational motions on the period length (inverse frequency) of a transient (single cycle) sinusoidal acceleration stimulus. However, self-motion is seldom purely sinusoidal, and up to now, no models have been proposed that take into account non-sinusoidal stimuli for rotational motions. In this work, the influence of both the period length and the specific time course of an inertial stimulus is investigated. Thresholds for three acceleration profile shapes (triangular, sinusoidal, and trapezoidal) were measured for three period lengths (0.3, 1.4, and 6.7 s) in ten participants. A two-alternative forced-choice discrimination task was used where participants had to judge if a yaw rotation around an earth-vertical axis was leftward or rightward. The peak velocity of the stimulus was varied, and the threshold was defined as the stimulus yielding 75 % correct answers. In accordance with previous research, thresholds decreased with shortening period length (from ~2 deg/s for 6.7 s to ~0.8 deg/s for 0.3 s). The peak velocity was the determining factor for discrimination: Different profiles with the same period length have similar velocity thresholds. These measurements were used to fit a novel model based on a description of the firing rate of semi-circular canal neurons. In accordance with previous research, the estimates of the model parameters suggest that velocity storage does not influence perceptual thresholds.

Show MeSH
Related in: MedlinePlus