Touch & the Vestibular System Flashcards
What is proprioception?
The awareness of your body’s orientation: posture, movements and changes in your equilibrium
What is somatosensation?
All sensory signals from the body
What does the vestibular system do?
detects motion, orientation, tilt, and gravity
What is spatial orientation important for?
Maintaining clear vision when moving
Keeping balance & posture
What 2 parts make up the Vestibular system?
The Semicircular canals
The Otolith organs
Where is the Vestibular system located?
In the middle/ inner ear
What are tactile sensations caused by?
mechanical displacements
What doe kinesthesis mean?
the position and movement of limbs
What is thermal sensation?
heat and cold
What is pain?
damage to body tissue
What are the 4 kinds of touch sensations?
tactile
kinesthesis
thermal
pain
What are the 3 semicircular canals called and what do they monitor?
Anterior: coronal plane (cartwheel)
Posterior: sagittal plane (nodding)
Horizontal/ Lateral: transverse plane (looking left/right)
What are the semicircular canals responsible for?
perceiving rotation
The semicircular canals join to what?
the vestibule with a swelling, an ampulla
When you move your head the liquid in the _________ causes the ______ to move.
ampulla
cilia
What do the otolith organs consist of?
The Utricule
The saccule
What is the Utricule responsible for?
detecting horizontal movement and acceleration
What is the Saccule responsible for?
detecting vertical movement and acceleration
What is the fluid sack, inside the otolith organs called?
The Macula
What is the fluid sack inside the Ampulla called?
Crista
What is translation perception?
detecting changes in movement
What is tilt perception?
changes in direction of gravity
Other than proprioception, what else do the vestibular nuclei in the medulla process?
Visual information
Other than connecting to the medulla to support vision, what other parts of the brain is the vestibular system connected to and what is controlled in these parts?
the motor cortex: movement
the cerebellum: balance
What is vection?
illusory perceptions of self motion caused by visual cues (without vestibular cues eg. old school screen savers)
What is motion sickness thought to be?
the result of conflicting information arising from the visual system and the vestibular system
What evolutionary benefit do conflicting senses (motion sickness) give us?
tells us we may be poisoned
What is a type of vestibular disorder?
Meniere’s syndrome
What is Meniere’s syndrome?
damage from an overflow of fluid - wrong information from the vestibular system
What is generally known as the combination of dizziness, imbalance, spatial disorientation and nausea?
Vertigo
What physiotherapy techniques can alleviate the symptoms of Meniere’s syndrome or vertigo?
- plasticity (practice movements)
- formation of internal models (what it should feel like)
- learning of limits (can/cant)
- sensory weighting (concentrate on one sense more than the other)
To detect vestibular problems we can examine?
Eye movements
What is haptic perception?
recognising objects or the world around you through touch
What are the 4 different types of touch receptors that give you the 4 different kinds of touch?
tactile mechanoreceptors
kinesthetic mechanoreceptors
thermalceptors
nociceptors (pain/ damage to body tissue)
What is the top layer and underlying layer of skin called?
the epidermis
the dermis
What are the 4 types of tactile mechanoreceptors?
merkel
ruffini
meissner
pacinian
What do kinaesthetic mechanoreceptors sense?
the position of limbs and the movements the muscles are making
What is the optimal temperature of the skin?
30-36 degrees
Other than heat what else can thermoceptors tell us about the objects we touch?
the tactile sensation of the object we touch (e.g. wood vs metal etc.)
What are Nociceptors?
receptors that respond to various forms of tissue damage and extreme temperatures (pain)
What are the 2 types of nociceptors?
A-delta fibres
C fibres
Which type of nociceptor would be used to carry stabbing pain messages to the brain?
A-delta fibers
What type of nociceptor would be used to carry dull pain messages to the brain?
C fibers
Which type of nociceptor is myelinated and what does this mean?
A-delta: they conduct signal rapidly
Which area of the brain is responsible for pain processing?
No single area
What does the gate control theory suggest?
Pain can be modulated by your spine even before it gets to your brain by an inhibitory inter-neuron
Gate control sends an interrupting signal to the second order neuron to stop the nosiceptors from taking a message of pain
What is an example of bottom-up processing of pain?
Tissue damage detected by noisieceptors and travels up your spine into your brains.
At each junction the messages are being relayed- the neuron is synapsing between neurons.
What is an example of top-down processing of pain?
The brain sending messages to the Gate Inter-neuron to stop pain coming through to the brain
Eg. thoughts that impact the amount of pain you think you’re feeling AND how much pain you actually are feeling because your brain can’t handle them
In what situation would your brain signal to the gate inter-neuron not to allow signals of pain through?
For Benign touch (touch that might hurt but is actually helping more- eg. rubbing)
Gate control sends an interrupting signal to the second order neuron to stop the nosiceptors from taking a message of pain
Where is the sensory cortex located?
Parietal lobe (across the top of your brain as if you were wearing a headband)
Why does phantom limbs occur?
Due to the corresponding somatosensory cortex for that limb still being active in the brain
OR
If the adjacent somatosensory cortex is active and accidentally passes on random activation
How can pain be treated if that part of the body isn’t actually there (phantom limb)?
Mirror therapy- they use a mirror to visually connect the idea of their missing foot actually being there. They can then modulate the pain response because it ‘resets’ the random activation that occurs in your somatosensory cortex for that area. Links visual with tactile sensation.
What is the defending pathway called, from the cortex to the spinal cord?
Endogenous opiates
How does pain affect attention?
Can’t focus as well with pain
Pain is usually less intense if distracted from it (or even sometimes concentrating on it reduce the pain)
Why is there a placebo effect?
Increased activation in the spinal cord (gate theory)
How are sensory processes represented in the brain?
Somatotopically
What is meant by the sensory homunculus?
The mapping of the sensory processes in the brain depending on the importance/ amount of touch that is received in different areas of the body (eg. the face because it controls most senses has a larger portion of brain than does the torso) After the face comes the fingers/ hand
What is tactile acuity measured using?
the 2 point touch threshold
What is the 2 point touch threshold?
The smallest separation at which two points applied simultaneously to the skin can be distinguished from one another
What is needed for higher tactile acuity?
sufficient concentration of mechanoceptors
A small enough receptor field for each receptor
Large enough area in the cortex given to process the 2 different touches at the same time equally
How is neural plasticity of sensory pathways proven?
By blindfolding people and watching the transfer away from touch to visual cortex activation in the brain as they learn more about not having vision
