PT  - JOURNAL ARTICLE
AU  - Min Jung Kim
AU  - Jorge Otero-Millan
AU  - Jing Tian
AU  - Amir Kheradmand
TI  - Measures of Spatial Orientation: Spatial Bias Analogs in Visual and Haptic Tasks
AID  - 10.1523/ENEURO.0233-22.2022
DP  - 2022 Jul 01
TA  - eneuro
PG  - ENEURO.0233-22.2022
VI  - 9
IP  - 4
4099  - http://www.eneuro.org/content/9/4/ENEURO.0233-22.2022.short
4100  - http://www.eneuro.org/content/9/4/ENEURO.0233-22.2022.full
SO  - eNeuro2022 Jul 01; 9
AB  - The primary sensory modality for probing spatial orientation can vary among psychophysical tasks. In the subjective visual vertical (SVV) task, a visual stimulus is used to measure perceived vertical orientation, while a haptic stimulus is used in the subjective haptic vertical (SHV) task. Here we examined disparity in SHV and SVV task results and asked whether it could be related to biases in probing different spatial estimates by each task. Forty-two healthy volunteers (mean ± SD age, 25 ± 10 years; 19 females; 21 left handed) were recruited. The effect of a task to measure spatial orientation was calculated as the difference between SHV and SVV values, and with the head upright and tilted 20° laterally. There was a task bias regardless of head position related to hand use in the haptic task but not handedness (mean head upright ± SEM: left hand, −3.7 ± 1.1°; right hand, 7.9 ± 1.0°). When this task bias was subtracted out, there was a similar spatial bias using each hand in the SHV task that was also comparable to the SVV task (mean head with left tilt: left hand, 3.9 ± 0.7°; right hand, 4.4 ± 0.7°; SVV, 4.9 ± 0.7°; mean head with right tilt: left hand, −4.6 ± 0.9°; right hand, −4.6 ± 0.8°; SVV, −4.7 ± 1.0°). These findings show that the disparity in visual and haptic measures of spatial orientation is primarily related to a modality-specific bias, and once the effect of hand use is removed from the haptic measurements, the spatial bias becomes comparable to the visual task.