Primary somatosensory cortex (S1) Flashcards
what is the location of S1
rostal parietal lobe
caudal to the central sulcus
what are the inputs into S1 (3)
somatosensory info from the thalamus
VPLn - below the neck (upper, lower limbs, and trunk)
VPMn - head, neck, and face
what are the outputs from S1 and why
M1 (frontal lobe) - influence ongoing motor actions
area 5 (parietal lobe) - higher level sensory processing and integration of somatosensory feedback with visual feedback
corticospinal tracts (down the spine) - influence ongoing sensory and motor processing in the spinal cord
what parts of the body have the largest representation in S1
areas more sensitive to sensory stimuli
what is the amount of space in the homunculus proportional to
number of receptors
how is the sensory homunculus organised
distal body parts (feet, genitals, hips) = medial
proximal body parts (hands and face) = lateral
what does area 3a measure
info from muscle spindles
what does area 3b measure
- input from SA1 and RA1 (merkel and meissner)
- detects force (SA1), location of stimulus (both), and change in force (RA1)
receives the most amount of info from the thalamus
what does area 1 measure
- input from RA1 and RA2 (meissner and pacinian)
- detects change in force (RA1) and stimulus motion (RA2)
what does area 2 measure
input from SA2 (ruffini)
- detects stretch caused by self motion
- integrates with info from 3b and 1 to allow separation of self vs. stimulus motion (helps with proprioception)
which areas get the most input from the thalamus
3b = most
1 and 2 = low amounts comparitively
what is the order of areas that the info moves through in S1
from 3b –> 1 –> 2
can also be 3b straight to 2
all info goes through 2 toto 5
where does area 5 output to
M1 - primary motor cortex and pre motor areas
where can info go from S1
into motor cortex
into anterior parietal cortex (area 5)
down spinal cord via descending corticospinal tracts
where is area 5 located
anterior parietal cortex
