NEUR 2600 Lecture Notes - Lecture 11: Tegmentum, Cerebellum, Error Detection And Correction
CHAPTER 11: HOW DOES THE NERVOUS SYSTEM RESPOND TO STIMULATION AND
PRODUCE MOVEMENT
● A hierarchy of movement control
○ Major components of the motor system
■ Cerebrum (forebrain): conscious control of movement
■ Brainstem: direct movements
■ Spinal cord: direct movements
○ With impaired brainstem or spinal-cord function, the forebrain can imagine
movements but can no longer produce them
○ Sequentially organized movement
■
○ Other regions of the motor system
■ Subcortical basal ganglia helps to produce the appropriate amount of
force for grasping
■ The cerebellum helps to regulate the timing and accuracy of movement
■ Relating the somatosensory and motor systems
● Afferent somatosensory information travels from the sensory
organs inward via the somatic nervous system
● Movement information travels out of the central nervous system
via a parallel efferent motor system
● Information coming from sensory receptors enters the CNS via
dorsal (posterior) root fibers
● Fibers leaving the spinal cord’s ventral side (anterior) carry
information from the spinal cord to the muscles
○ They too bundle together as the fibers exit the spinal cord,
forming an anterior root
●
● Spinal segments and dermatomes
○ Each spinal segment corresponds to a region of body
surface called a dermatome
● Layering in the neocortex
○ Layer IV (afferent) is relatively thick in the sensory cortex
and relatively thin in the motor cortex
○ Layer V (efferent) is relatively thick in the motor cortex and
relatively thin in the sensory cortex
○ Forebrain: initiating movement
■ Lashley (1951)
● We perform skilled movements too quickly to rely on feedback
about one movement before shaping the next
● Time required to receive feedback about the first movement
combined with the time needed to develop a plan for subsequent
movement and send a corresponding message to muscles is
simply too long for effective action
● Argued that movements must be performed as motor sequences,
with the next sequence held in readiness while the ongoing one is
under way
■ Motor sequence
● Movement modules preprogrammed by the brain and produced as
a unit
■ Initiating a motor sequence
● Most of our motor learning is mastering sequences of action
○ As one sequence is being executed, the next sequence is
being prepared to follow the first smoothly
● Frontal lobes
○ Prefrontal cortex: plans complex behaviour
○ Premotor cortex: produces the appropriate complex
movement sequences
○ Primary motor cortex: specifies how each movement is to
be carried out
■ Specializes in producing focal skilled movements,
such as those of the arms, hands, and mouth
■ People with damage to M1 have difficulty reaching
and shaping their fingers to perform various hand
grasps
Document Summary
Chapter 11: how does the nervous system respond to stimulation and. With impaired brainstem or spinal-cord function, the forebrain can imagine movements but can no longer produce them. Subcortical basal ganglia helps to produce the appropriate amount of force for grasping. The cerebellum helps to regulate the timing and accuracy of movement. Afferent somatosensory information travels from the sensory organs inward via the somatic nervous system. Movement information travels out of the central nervous system via a parallel efferent motor system. Information coming from sensory receptors enters the cns via dorsal (posterior) root fibers. Fibers leaving the spinal cord"s ventral side (anterior) carry information from the spinal cord to the muscles. They too bundle together as the fibers exit the spinal cord, forming an anterior root. Each spinal segment corresponds to a region of body surface called a dermatome. Layer iv (afferent) is relatively thick in the sensory cortex and relatively thin in the motor cortex.
