l13 somatosensory Flashcards
4 modalities of somatosensation
Exteroceptor
Mechanoreceptor
Thermoreceptors
Nocireceptors
Proprioceptor
Muscle + Joints
mechanoreceptor Meissnes
- Rapid
- light touch
- low frequency
close to skin
mechanoreceptor merken
slow
pressure and texture
close to skin
mechanoreceptor Pacinian
rapid
deep pressure, high frequency
deep in skin
mechanoreceptor ruffini
slow
skin stretch
sustain pressure
different classes of primary afferent
aplha: skeletal muscle proprio (biggest)
beta: touch 2nd
delta: pain and temp (rapid speed) 3rd (myelinated)
C: pain and temp (slow speed) 4th (unmyelinated)
Information pathway
Dorsal root ganglia (cell bodies of psedounipolar)-> dorsal horn
->
1. Dorsal column medial lemniscus pathway (ipsilateral, decussate at medulla)
Spinothalamic tract (bilateral)
dorsal column carry?
Proprio
Touch
spinothalamic tract carry?
pain, temp, itch
what target VPL ventral posterolateral nucleus
touch from body
what target VPS ventral posterior superior nucleus
proprio
ventral posteriormedial nucleus
touch face
touch face (go to thelamus via trigeminal thalamic tract, cell bodies in trigeminal ganglion)
primary afferent neuron alpha
skeletal muscle proprio (biggest)
beta
touch 2nd
delta
pain and temp (rapid speed) 3rd (myelinated)
C
pain and temp (slow speed) 4th (unmyelinated)
1 touch sensation
- Function: fine touch + texture discrimination.
- Location: postcentral gyrus, posterior to 3b.
Role: integrates sensory information from 3b + helps in the perception of the texture + shape objects
3b tactile information, touch pressure
- Function: fine touch + texture discrimination.
- Location: postcentral gyrus, anterior to 1
- Role: integrates sensory information from 3b + helps in the perception of the texture + shape objects
3a proprioception
- Location: anterior of the postcentral gyrus.
Role: muscle spindles +joint receptors, inform brain about position + movement
2 direction and orientation
Intergration of information (primary sensory cortex, this information of the sensory come from where,…)
* Function: processes complex aspects of touch
* Location: Located in the postcentral gyrus, posterior to area 1.
Role: Area 2 receives input + integrates information to provide a comprehensive understanding of object properties
Labeled-Line Processing
specific sensory receptors and their associated pathways transmit specific sensory information, ensuring that the brain accurately interprets different types of stimuli
