Neuro Atlas

NEUROPHYSIOLOGY
Sensory Pathways: I
Cerebral cortex:
postcentral gyrus
Posterior limb of
internal capsule
Ventral posterolateral
(VPL) nucleus of
thalamus
Mesencephalon
(cerebral peduncles)
Medial lemniscus
Spinothalamic tract
Gracile nucleus
Cuneate nucleus
Lower part of
medulla oblongata
Reticular formation
Cervical part
of spinal cord
Lateral
spinothalamic tract:
pain, temperature
Ventral (anterior)
spinothalamic tract:
touch, pressure
Fasciculus gracilis
Fasciculus cuneatus
Dorsal (posterior) spinal
root ganglion
Proprioception,
position
Touch,
pressure,
vibration
Pain,
temperature
Lateral cervical nucleus
Spinocervical tract
Large
myelinated
fibers
Small
myelinated
and unmyelinated
fibers
Lumbar part
of spinal cord
©
FIGURE 2.29
SOMESTHETIC SYSTEM OF THE BODY •
Pain, temperature, and pressure sensations below the head ultimately
are conveyed to the primary somatosensory cortex (postcentral
gyrus) by the anterolateral system (spinothalamic and spinoreticular
tracts). The fasciculus gracilis and cuneatus of the spinal
lemniscal system convey proprioceptive, vibratory, and tactile sensations
to the thalamus (ventral posterolateral nucleus), whereas
the lateral cervical system mediates some touch, vibratory, and
proprioceptive sensations (blue and purple lines show these dual
pathways). Ultimately, these fibers ascend as parallel pathways to
the thalamus, synapse, and ascend to the cortex.
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