Balance sense is the ability of the body to maintain the center of mass over its base of support. That is to say, the upright position of the body needs to be maintained steadily over the base, that is, the legs.
Maintaining the balance during movements like walking, running, jumping or performing a cartwheel are all coordinated by a complex set of sensorimotor control systems. Involuntary movements and movements of surroundings cause the shift in the center of mass of the body are sensed by the balance system.
The complex network in our body that maintains balance involves coordination of various sensory inputs and integrated motor responses.
Information from various sensory organs and sensations determine the position and movement of the body.
These sensations send signals to the brain about how our body is positioned in the space and any change in position due to movement. The vestibular system gives information of the head movement and head position, visual inputs give information about the position of the body and the brain receives inputs from the muscles about position and movements.
Vestibular system also sends sensory information about the body with respect to gravity, linear movements like moving forward, backwards, up and down and also rotational movements like turning around or sideways. All the information is received by the brain to process the next course of action to compensate the change of position and bring about the center of mass.
Cerebellum and cerebral cortex:
This information is processed by the cerebellum and the cerebral cortex. The cerebellum coordinates and regulates the posture, movement and helps in maintaining the balance. The cerebral cortex involves when there is a requirement for higher order thinking and memory like what manipulation can be done to restore balance in the body.
Brain processes the sensory inputs and forms new nerve pathways to send commands to muscles of the body to respond. With repetition, these pathways strengthen and become automatic responses to stimuli. Athletes and dancers practice to maintain and strengthen these pathways, that even complex movements become automatic over a period of time.
Motor commands are sent to vision and muscles of the body for proper positioning and maintaining the balance. The motor inputs received by the eyes help in turning the gaze to the direction of maintaining the balance during:
Disorders of the balance system:
The complex network of balance systems can get disrupted by any of the above mentioned pathways. Injury, disease and aging process can cause these disruptions. Symptoms such as dizziness, vertigo, vision problems, nausea, fatigue and difficulty in concentration are the indications of disturbances in balance systems.
Diagnosis and treatment of balance disorders are done and underlying cause can be treated with medicines or vestibular rehabilitation therapy.