4. Somatosensory Integration Flashcards
define somatosensation
the ability to perceive what happens on surface of our boday or within it.
info from skin, muscles and joints
define somatosensory integration
ability of the CNS to integrate different sources of stimuli to create a powerful, motor response output
sensory systems move information from periphery to CNS, where it is used for…
- ## perception• Movement control
• Regulation of internal organs
exteroceptive system
external stimuli, applied to skin
(mechanical, thermal, nociceptive)
e.g. VZV infection -> herpes zoster
propioceptive
info about the position of our body in space
interoceptive system
internal conditions of our own body
kinestasia
info about our own movement
what’s another name for a slowly adapting receptor
tonic receptor
- response persists over time
what’s another name for a rapidly adapting receptor
phasic receptor
- response declines over time
Name some receptor subtypes and their correspondent ski stimulus
Hair follicles Light brush Meissner corpuscle Dynamic deformation Pacinian corpuscle Vibration Merkel cell-neurite complex Indentation depth Ruffini corpuscle Stretch
how does the pacinian corpuscle work?
pressure –> distortion of nerve ending
- creation of action potential
define pain
unpleasant sensory physical or emotional
experience
associated with actual or potential tissue damage
pain is ____________________.
subjective
- pain threshold varies among individuals.
- varies in the same individual at different times
Nociceptive damage: somatic, inflammation, visceral
somatic
inflammation
visceral
Neuropathic damage
nerve damage
acute pain?
chronic pain?
Acute pain: Aδ fibres
Chronic pain: C fibres
what is TRP?
transient receptor potential
define TRP
molecules that detect noxious stimuli
transduction of physical energy into action potentials
name TWO exteroceptive pathways
dorsal column-medial lemniscal pathway: touch, proprio
spinothalamic tract: pain, temp
(not separate!!!!!)
two exteroceptive pathways are not separate:
evidence
- Injuries of the dorsal column-medial lemniscal do not cause a total elimination of the perception of touch or proprioception.
- Lesions of the spinothalamic tract do not cause a total elimination of the perception of pain or temperature.
compare unstretched muscle with stretched muscle
unstretched: AP firing at constant rate
stretched: rate of AP increases
The somatosensory cortex is
somatotopic
posteriori parietal association cortex
• Position of the body and objects in space (“where” pathways
prefrontal dorsolateral association cortex
decision to INITIATE MOVEMENTS
what is apraxia?
Damage to parietal or prefrontal lobe:
- motor planning
prefrontal cortex –> premotor cortex
- motor programmes
premotor cortex –> motor cortex
compare the roles of the premotor cortex and the primary motor cortex…
premotor: organizes sequences
motor: executes actions
name 2 descending motor pathways
pyramidal tracts (voluntary control) extrapyramidal tracts (automatic control)
what did stephen hawking suffer from?
ALS
Amyotrophic
Lateral Sclerosis
what is ALS?
- neurological condition
- progressive
- muscles under voluntary control
- individuals lose ability to speak, walk, eat, drink
- muscles that are not used degenerate
- most die within 3-5 years of respiratory failure
