Parallel encoding of recent visual experience and self-motion during navigation in Drosophila

When two different images are presented separately to each eye, one experiences smooth transitions between them. Previous studies have shown that exposure to signals from other senses can enhance perceptual awareness of stimulation-congruent images. Surprisingly, despite our ability to infer perceptual consequences from bodily movements, evidence that action can have an analogous influence on visual experience is scarce and mainly limited to local (hand) movements. Here, we investigated whether one’s direction of locomotion affects perceptual awareness of optic flow patterns. Participants walked forwards and backwards on a treadmill while viewing highly-realistic visualisations of self-motion in a virtual environment. We hypothesised that visualisations congruent with walking direction would predominate in visual awareness over incongruent ones, and that this effect would increase with the precision of one’s active proprioception. These predictions were not confirmed: optic flow consistent with forward locomotion was prioritised in visual awareness independently of walking direction and proprioceptive abilities. Our results suggest that kinaesthetic-proprioceptive processing plays a limited role in shaping visual experience. This seems at odds with Bayesian accounts of perception but is in-line with Cancellation theories, which imply that crossmodal influences of self-generated signals are suppressed as a redundant source of information about the outside world.

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Spatial Hearing in Children with Visual Disabilities

Perception ◽

10.1068/p270105 ◽

1998 ◽

Vol 27 (1) ◽

pp. 105-122 ◽

Cited By ~ 62

Author(s):

Daniel H Ashmead ◽

Robert S Wall ◽

Kiara A Ebinger ◽

Susan B Eaton ◽

Mary-M Snook-Hill ◽

...

Keyword(s):

Visual Experience ◽

Space Perception ◽

Spatial Hearing ◽

Sound Sources ◽

Visual Disabilities ◽

Auditory Space ◽

Hearing Ability ◽

History Of ◽

Total Blindness ◽

Self Motion

A study is reported of the effect of early visual experience on the development of auditory space perception. The spatial hearing of thirty-five children with visual disabilities (twenty-two with congenital total blindness) was compared with that of eighteen sighted children and seventeen sighted adults. The tests provided a comprehensive assessment of spatial-hearing ability, including psychophysical estimates of spatial resolution in the horizontal, vertical, and distance dimensions, as well as measures of reaching and walking to the locations of sound sources. The spatial hearing of the children with visual disabilities was comparable to or some-what better than that of the sighted children and adults. This pattern held even when the group with visual disabilities was restricted to those children with congenital total blindness; in fact, some of those children had exceptionally good spatial hearing. These findings imply that the developmental calibration of human spatial hearing is not dependent on a history of visual experience. It seems likely that this calibration arises from the experience of changes in sound-localization cues arising from self-motion, such as turning the head or walking. As a practical matter, orientation and mobility instructors may reasonably assume that individuals with visual disabilities can use their hearing effectively in day-to-day travel situations.

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