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Unformatted text preview: s of the prefrontal cortex, are involved in
motor planning. The M1 runs along the pre-central gyrus and
is for initiating voluntary movement. From M1 goes to spinal
cord to carry out that ﬁnal movement. Feedback is very
important in all of this; includes S1 (runs along postcentral
gyrus) codes for touch sensations and body sensations. Also
will have feedback from the cerebellum which will encode for
posture and body postioning. The basal ganglia and
cerebellum together provide very important modulations of
these motor functions. The basal ganglia is a major player. Overview of Motor Pathways and Structures!
Hierarchical organization with 3 levels of control over the musculoskeleton –
spinal cord, brainstem and cerebral cortex. !
The spinal cord includes the ﬁnal common pathway for all motor control and
interneurons that integrate sensory feedback from muscles and joints with
descending commands from higher centers. !
The brain stem, including regions such as the reticular formation (RF) and
vestibular nuclei (VN), selects and enhances the spinal repertoire by
improving postural control and locomotion. !
The cerebral cortex supports a large and adaptable motor repertoire involved
in goal-directed reaching movements. !
Motor planning and visual feedback are provided through several parietal
and premotor regions, including the premotor cortex (PMC) and the
supplementary motor area (SMA). !
The primary motor cortex (M1) contributes the largest number of axons
to the corticospinal tract and receives input from other cortical regions
involved in motor planning. !
Somatosensory information is provided through the primary
somatosensory cortex (S1), parietal cortex area 5, and cerebellar
The basal ganglia (BG) and cerebellum (C) provide important
modulations of motor function through their connections with M1 and
other brain regions. !
Scott (2004) Nature Reviews Neuroscience! Overview of Motor Pathways and Structures! 24:00 Another view:
Can think of these
movement as two
stages. First stage is
the planning of the
movement, select goal
and plan that out.
Done by association
cortex like the parietal
lobe and the PFC, and
its going to take the
SMA and PMC to plan
out speciﬁc muscle
actions, and will need
BG and C to
modulation - when to
keep movement going,
when to stop it. The
signals then get sent
to M1 and the
carry out (execute)
that movement) Disorders of Motor Pathways and Structures!
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- Fall '11