18. Control of balance / posture together with the movements of the eye and head. Perception of spatial position Flashcards
The role of Equilibroception
Sense of balance and for spatial orientation
The role of Ampullary crists (Equilibroception)
detect angular acceleration of the head.
The role of Maculae staticae (Equilibroception)
detect linear acceleration, tilt of the head and gravity
Where are Maculae staticae (Equilibroception)?
in the utricle and saccule
Pattern of membrane potential and firing of the hair cells
-> What are characteristics of stereo cilia? (5)
- 30-300pcs/ hair cell,
- large microvilli,
- arranged by size,
- contain actin filaments,
- contain fimbrin -rigidity.
Pattern of membrane potential and firing of the hair cells
-> What are characteristics of Kinocilium (5)
- 1pc/ hair cell
- a real cilium: 9 + 2 array of microtubules
- taller then the stereocilia
How are kinocilia oriented?
- kinocilia are oriented in opposite direction on each side of the striola
How are kinocilia on utricle oriented?
kinocilia are facing the striola
How are kinocilia on saccule oriented?
- utricle - kinocilia are facing the striola
How are kinocilia oriented?
- kinocilia are oriented in opposite direction on each side of the striola
How can this arrangment affect the role of kinocilia?
allows sensing linear acceleration in every directions
Angular acceleration and movements of the endolymph
-> Name these 3 directions
Name The semicircular canals
Name The semicircular canals
Coordinated firing of the ampulla partners
-> The role of Vestibulo-ocular reflex (VOR)
Vestibulo-ocular reflex (VOR)- keeps the eyes focused on target while the head is moving.
Coordinated firing of the ampulla partners
-> Explain Vestibulo-autonom reflex
Disharmony of vestibular and visual information causes dizziness, nausea and vomiting (ie:. motion thickness).
3 characteristics of Vestibular nuclei
- rostral medulla and caudal pons
- cranial nuclei for the vestibular nerve
- Efferents to the III., IV. , VI. cranial nuclei: MLF
Vestibular Nuclear complex
-> Name the 4 nuclei
SVN: Superior (Bechterew)
MVN: Medial (Schwalbe)
LVN: Lateral (Deiters)
IVN: Inferior (Roller)
Which structures involving in Cortical representation of vestibular signals?
Vestibular nuclei-MLF-thalamus-vestibular cortex
Cortical representation of vestibular signals
-> Name the Multisensory vestibular cortex areas
- parieto-insular vestibular cortex (PIVC)
- medial superior temporal area (MST) –part of the
posterior parietal cortex
Cortical representation of vestibular signals
-> What is the role of parieto-insular vestibular cortex (PIVC)?
Encodes vestibular signals about position and movement of the head
Cortical representation of vestibular signals
-> What is the role of medial superior temporal area (MST) –part of the posterior parietal cortex?
integrate vestibular and visual signals necessary for self-motion perception
What is the role of Posterior parietal multimodal association cortex? (3)
- sensory signals from many modalities, with copy signals from motor structures
- codes the spatial locations of goals for movement
- converts the sensory locations of stimuli into the appropriate motor coordinates required for making directed movements
Explain Somatogyral illusions (ampullae)- false sensations of rotation
- when a pilot is in a turn and bends the head downward or backward : the turn activates one semicircular canal and the head movement activates another in a different plane. It feels like the aircraft is rolling.
- a sudden return to level flight following a gradual, prolonged turn that went unnoticed by the pilot. It causes an illusion that the aircraft is banking in the opposite direction.
What are
Somatogravic illusion (maculae) caused by?
linear accelerations or decelerations.
What are the 2 Cerebellar connections?
- cerebello-vestibulartract
- vestibulo-cerebellar tract
Describe cerebello-vestibulartract
- vestibular nuclei
- n. fastigii
Describe vestibulo-cerebellar tract
- 1st and 2nd order neurons
- mossy fibers
- Flocculonodular lobe (vestibulocerebellum)
Connections with the spinal cord
-> The role of Medial vestibulospinal tract
- Vestibulo-cervical reflex
- Contols position of the head
Connections with the spinal cord
-> The role of Lateral vestibulospinal tract
- Vestibulo-spinal reflex (labyrinth reflex
- Controls position of the body, and postural equiriblium
Connections with the spinal cord
-> Characteristics of Medial spinovestibular tract (MSVT)
- Bilateral
- Descends within The medial longitudinal fasciculus (MLF)
- Ends in the cervical spinal cord segments
Connections with the spinal cord
-> Characteristics of LVST
- Ispilateral
- Innervates the entire length of the spinal cord
Central regulation of posture
-> What are the 3 types of controls?
- Somatosensory control
- Vestibulo-cerebellar control
- Control of eye movements
Central regulation of posture
-> The role of Somatosensory control
helps to identify the body part which is moving, or is in touch with the ground.
Central regulation of posture
-> Afferents and efferents of Vestibulo-cerebellar control
Afferents : vestibulocerebellart tract
Efferents:
- Lateral vestibulospinal tract : helps to maintain an upright and balanced posture
- Medial vestibulospinal tract : controls position of the head, neck, and eyes in response to changes in posture
Central regulation of posture
-> What are the 3 types of controls?
- Somatosensory control
- Vestibulo-cerebellar control
- Control of eye movements
Central regulation of posture
-> Describe Control of eye movements
horizontal and vertical gaze-tracking a moving object
vestibulo-ocular reflex (VOR)- keeps the eyes focused on target when the head moves (Szentágothai, Hőgyes)
Central regulation of dynamic control of posture
-> Describe cortex
Integrator-posterior parietal cortex
body schema: register of the posture of body parts in space, it is updated during body movement.
Central regulation of dynamic control of posture
-> Describe Basal ganglia:
sensoryguided and emotionally guided locomotor control
Central regulation of dynamic control of posture
-> The role of Cerebellum
Controls postural equiriblium
Central regulation of dynamic control of posture
-> The role of Brainstem control
Reticulospinal tract: control of postural muscle tone
Vestibulospinal tracts (VST): control of postural equilibrium
Central regulation of dynamic control of posture
-> The role of spinal cord
- Does not enable to control postural equilibrium alone
- Spinal reflexes are involved in the control of posture
- Supraspinal control is necessary
Cognition of bodily information
Transmission of bodily information
