Vestibular system Flashcards
The vestibular system is influenced by vection, body tilt and rotation. What is vection?
Vection is the sense of movement of the body in space provided entirely by visual cues. For example, when sitting on a train and watching another train move by, we experience a sense of self-motion.
What are the semicircular canals responsible for?
The semicircular canals are responsible for detecting head location. There are 3 canals on horizontal plane, vertical plane and perpendicular vertical plane
Following movement inside the utricle of the semicircular canals, the cupula (the gel-like substance) lags behind causing inertia. What is signalled by the amount of force of movement, and how is this transduced into neural firing?
The amount of force detected in the cupule signals the speed of acceleration, and the transduction happens as a result of the cilia of the hair cells bending, which causes polarisation.
The saccule lies in a vertical plane. Although it can signal front/ back acceleration, what is it’s constant signal acceleration direction, which also provides a strong reference frame for vision?
Gravity is the saccule’s constant acceleration direction: Up/ down. Gravity provides a strong reference frame for vision.
The vestibular system interacts with other perceptive systems such as haptics.
In an experiment where 8 tactile buzzers were placed around the belly, what was the effect on perceived buzz location when head and gaze was fixed leftward either before the buzz, or when the head was turned leftward after the buzz? The buzz position is halfway between the front and side of the body in the leftwards direction.
Why does this ocurr?
When the gaze was fixed leftward before the buzz, perception of the buzz location was rightward.
When the head was turned leftward after the buzz, the perception of the buzz was leftward.
This is because of a bias towards the body’s midline. When I turn your head my head after the buzz occurs, I imagine that my head is not turned as leftward as it actually is; the midline is already a really strong reference since the head started there.
