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KEY POINTS Cats, like humans, rely on vision to navigate in complex environments. In cats walking along a horizontally placed ladder we show that visual information required for accurate stepping is collected non-uniformly across the stride cycle. Brief denial of visual input during a swing prolongs the next stance of that forelimb. Denial of visual input during a stance prolongs this stance, as well as the next swing and stance. Denial during the first half of stance has a greater effect than during the second half. The phase-dependence of the use of vision for accurate stepping and the pattern of affected swings and stances are closely related to the previously described pattern of gaze behavior in cats. This new knowledge opens new perspectives for research into neuronal mechanisms of visuo-motor coordination and visual function during walking, and for understanding related disorders. ABSTRACT Locomotion on complex terrains often requires vision. However, how vision serves locomotion is not well understood. Here we asked when visual information necessary for accurate stepping is collected and how its acquisition relates to the step cycle. In cats of both sexes we showed that a brief (200-400 ms) interruption of visual input can rapidly influence cat's walking along a horizontal ladder. Depending on the phase within the step cycle, a 200 ms darkness could be fully tolerated without any changes to the strides, or lead to minor increases of stride duration. Effects of 300-400 ms visual input denial, which typically prolonged stances and/or swings, also depended on the phase of the darkness onset. Increase of the duration of strides was always shorter than the darkness duration. We conclude that visual information for planning a swing is collected starting from the middle of the preceding stance till the beginning of the current swing. For a stance (and/or a swing of the other paw), visual information is collected starting from the end of the previous stance and until the middle of the current stance. Acquisition of visual information during these windows is not uniform, but depends on the phase of the step cycle. Notably, both the extension of these windows and their non-homogeneity are closely related to the pattern of gaze behavior in cats, described previously. This new knowledge will help guiding research and understanding of neuronal mechanisms of visuo-motor integration and modulation of visual function by strides during locomotion. Abstract figure legend: Accurate stepping on crosspieces of a horizontal ladder requires vision. We show that collection of visual information for locomotion is not uniform across the stride cycle. In cats, brief denial of visual input during a swing prolongs the next stance of that forelimb. Denial of visual input during a stance prolongs this stance, as well as the next swing and stance. This dependence of the acquisition of visual information for locomotion and the pattern of affected swings and/or stances are closely related to the pattern of gaze behavior in cats, described previously. This article is protected by copyright. All rights reserved. |
