Neuronal Control of Posture in Blind Individuals

Area of Science:

• Neuroscience
• Human Physiology
• Sensory Integration

Background:

• Postural control relies on integrating sensory information, with vision playing a key role for sighted individuals.
• Blind individuals must compensate for the absence of visual input by utilizing other senses for balance.
• The sensorimotor cortex is crucial for processing somatosensory information and executing motor commands for posture.

Purpose of the Study:

• To investigate brain activation patterns in the sensorimotor cortex of blind and sighted individuals during postural control.
• To determine if blind individuals exhibit altered sensorimotor cortex activity due to increased reliance on somatosensory information.
• To compare the neural strategies for balance control between blind and sighted individuals under varying sensory and surface conditions.

Main Methods:

• Functional Near InfraRed Spectroscopy (fNIRS) measured brain activation in the sensorimotor cortex.
• Postural sway was quantified using a pressure distribution measuring plate.
• Participants included ten blind and ten age- and sex-matched sighted individuals.

Main Results:

• Blind individuals showed increased postural sway on unstable surfaces with eyes open compared to sighted individuals.
• Blind individuals demonstrated significantly greater sensorimotor cortex activation across all conditions, especially with eyes open.
• Sighted individuals showed increased brain oxygenation primarily during eyes-closed and unstable surface conditions.

Conclusions:

• Blind individuals exhibit heightened sensorimotor cortex activation, suggesting enhanced sensory integration for postural control.
• The sensorimotor cortex adapts in blind individuals to effectively manage balance without visual input.
• These findings highlight the brain's plasticity in reallocating resources for sensory compensation.