Resting-state functional magnetic resonance imaging study on the effects of visual status on walking-related brain...

Visual input supports locomotion through sensorimotor integration. However, the neural mechanisms underlying how the brain adapts to degraded vision are not well understood. This study investigated the effects of visual occlusion on interactions between regions within the sensorimotor network.

Twelve healthy young adults (8 males, 4 females; mean age 24.0 ± 2.1 years) were recruited from the Department of Ophthalmology at Peking University Third Hospital between December 2024 and September 2025. Pattern-reversal visual evoked potentials were recorded under both normal vision and visual occlusion condition (Snellen 20/60 acuity). We acquired resting-state functional magnetic resonance imaging (rs-fMRI) data to calculate the amplitude of low-frequency fluctuations (ALFF) and seed-based functional connectivity (FC) focused on visuomotor integration regions. A one-way repeated-measures analysis of variance was conducted with three within-subject conditions: seated rest, level walking with normal vision, and level walking with visual occlusion.

Stimuli consisted of checkerboard patterns with large (1°) and small (15') checks. Under 1° visual stimulation, visual occlusion prolonged binocular P100 latency (117.00 ± 8.55 ms vs . 111.81 ± 5.12 ms; 116.78 ± 9.79 ms vs . 110.96 ± 4.28 ms; all P <0.05) and reduced N75-P100 amplitude (5.798 ± 2.372 μV vs . 8.613 ± 3.949 μV; 6.230 ± 2.459 μV vs . 7.453 ± 2.692 μV, all P <0.05). For 15' stimulation, occlusion decreased both binocular N75-P100 (5.935 ± 3.500 μV vs . 10.794 ± 5.249 μV; 3.991 ± 1.585 μV vs . 10.361 ± 3.143 μV, all P <0.001) and P100-N135 amplitudes (6.218 ± 3.516 μV vs . 12.499 ± 4.236 μV; 4.427 ± 2.218 μV vs . 10.767 ± 4.904 μV, all P <0.001). Rs-fMRI analysis showed reduced ALFF in the right paracentral lobule after walking (peak Montreal Neurological Institute [MNI] coordinates: 3, -39, 66; P <0.001, F = 14.009). Walking activated multiple visuomotor pathways (all P <0.001), including the bilateral calcarine and middle temporal gyri, the right calcarine and middle frontal gyri, the bilateral supplementary motor area and right cuneus, and the bilateral precentral gyrus and right cerebellar lobule VI. The visual occlusion strengthened FC between the right precentral and the right middle frontal gyri (peak MNI: 27, 57, 27; F = 16.456, P <0.001).

Basic visuomotor pathways demonstrate consistent activation to maintain locomotion. Increased functional connectivity between the right precentral and middle frontal gyri serves as a compensatory mechanism for reduced visual input.