Neural Correlates of Postural Balance: EEG Responses During a Visuospatial Attention Task

The term equilibrium is related to Newton's first law and, as used in mechanics, describes the state where the effect of the forces acting on an object is zero. Equilibrium is divided into two types: static and dynamic. Static equilibrium is the ability to maintain posture without any external forces. This type of equilibrium requires the center of gravity to be kept within the support base. Dynamic equilibrium, on the other hand, is the equilibrium maintained during motion. It requires a controlled shift of the center of gravity.

Equilibrium is controlled by the proprioceptive, visual, and vestibular systems. The perception of one's own motion and balance is encoded by proprioceptive and visual signals, along with the vestibular system's perception of inertial motion. Connections between the vestibular nuclei and the cerebellum, hippocampus, prefrontal and parietal cortices provide information for cognitive functions such as spatial functions, navigation, and memory. Adaptation to postural changes in complex environments is known to be achieved through the coordinated and seamless functioning of these structures. In addition to these main systems, spatial orientation has been shown to be a crucial component for balance and posture control. Information from these systems is integrated and processed depending on the task and environment. The interaction and processing of sensory components can also be influenced by ongoing body movements, anticipation, prediction, or instructions. This sensory processing process can depend on many factors. The integration process can also go through a process involving inhibition. For example, standing on the deck of a station, a moving train may cause a person to perceive their own movement. The visual inputs that produce this sensation need to be excluded or blocked from the integration process. Like reweighting, inhibition is a dynamic process. While sensory information continuously flows into the brain, incompatible sensory channel(s) must be identified and blocked from integration.

Visual-spatial skills are of great importance for functional independence; they enable us to interact with our environment in 2 and 3 dimensions, perceive the shapes of objects in space, understand the location of objects in space, and understand the spatial orientation of our body. Visual-spatial abilities also include responses to scanning space, reaction speed, visualization, orientation, and sustained or focused attention. Visual stimuli provide individuals with information about the environment. Since visual-spatial codes are three-dimensional, the environment can be perceived in three dimensions.

Visual-spatial attention, a component of visual-spatial components, selects relevant sensory information and supports the preparation of responses to this information. It is defined in the Lifelong Development Dictionary published by the APA as 'the way an individual distributes their attention to the visual field'. It selects relevant sensory information and supports the preparation of responses to this information. It allows for selective processing of visual information by prioritizing a specific visual field section. Visual-spatial attention can be directed from one direction to another voluntarily or involuntarily.

It is known that cognitive and motor skills develop in a coordinated manner in both children and older adults and that there is a significant relationship between them. There are studies in the literature that address balance and visual-spatial skills and indicate a relationship between them. In their study investigating the relationship between these two functions in stroke patients, Embrechts et al. revealed that reduced visuospatial skills can cause balance and posture problems. It has been suggested that visuospatial input is essential for proactive planning and adjustments to maintain stability in dynamic and complex environments and allows for preventive regulation of movement patterns that provide safe movement and postural control.