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    Jingying T.A. Department of Physiology

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    This document discusses motor control pathways in the brain and spinal cord. It describes the motor cortex and its role in controlling muscle movement. It also outlines several descending tracts that originate in the brainstem, cerebellum, and basal ganglia and project to the spinal cord, including the pyramidal tract, rubrospinal tract, vestibulospinal tract, and reticulospinal tract. These tracts are involved in fine motor control, balance, and locomotion. Additionally, the cerebellum and basal ganglia receive inputs from various sensory and motor areas and influence motor cortex output and movement initiation.

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    Jingying T.A. Department of Physiology

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    api-19916399
    169 views19 pages
    This document discusses motor control pathways in the brain and spinal cord. It describes the motor cortex and its role in controlling muscle movement. It also outlines several descending tracts that originate in the brainstem, cerebellum, and basal ganglia and project to the spinal cord, including the pyramidal tract, rubrospinal tract, vestibulospinal tract, and reticulospinal tract. These tracts are involved in fine motor control, balance, and locomotion. Additionally, the cerebellum and basal ganglia receive inputs from various sensory and motor areas and influence motor cortex output and movement initiation.

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    nervous system 5

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    This document discusses motor control pathways in the brain and spinal cord. It describes the motor cortex and its role in controlling muscle movement. It also outlines several descending tracts that originate in the brainstem, cerebellum, and basal ganglia and project to the spinal cord, including the pyramidal tract, rubrospinal tract, vestibulospinal tract, and reticulospinal tract. These tracts are involved in fine motor control, balance, and locomotion. Additionally, the cerebellum and basal ganglia receive inputs from various sensory and motor areas and influence motor cortex output and movement initiation.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    169 views19 pages

    Jingying T.A. Department of Physiology

    Uploaded by

    api-19916399
    This document discusses motor control pathways in the brain and spinal cord. It describes the motor cortex and its role in controlling muscle movement. It also outlines several descending tracts that originate in the brainstem, cerebellum, and basal ganglia and project to the spinal cord, including the pyramidal tract, rubrospinal tract, vestibulospinal tract, and reticulospinal tract. These tracts are involved in fine motor control, balance, and locomotion. Additionally, the cerebellum and basal ganglia receive inputs from various sensory and motor areas and influence motor cortex output and movement initiation.

    Copyright:

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    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    of 19

    Chapter 5

    Jingying T.A.
    Department of physiology
    willa2004@yahoo.com
     review
     motor cortex
     descending tracts (brain stem, cerebellum and
    basal ganglia)
    review
     motor neuron:
    α-motor neuron:
    γ-motor neuron:
    review

     motor unit: a motor neuron plus the muscle cells it


    innervates constitutes an important functional unit , called a
    motor unit.
    review

    proprioceptor
    review

    Cord functions:
     Muscle stretch reflex (based on muscle spindle)
     Golgi tendon reflex
     Flexor reflex and the withdrawal reflexes
     Crossed extensor reflex
     Reflexes of posture and locomotion
     Scratch reflex
     Autonomic reflexes in the spinal cord
    motor cortex
    anterior to the central cortical sulcus;
    occupying about the 1/3 of the frontal lobes;
     primary motor cortex: in the first convolution; excitement of neurons
    excite a pattern of muscles;

     premotor area: cause much more


    complex pattern of movement; deve
    lop “motor image”.
    supplementary motor area:
    cause bilateral muscle
    contraction; provide background
    for the finer motor.
    primary motor cortex
    motor cortex

    distribution features of somatic movement:


     contra lateral control (with bilateral control for facial

    muscles);
     upward down;

     topographical organization;

     area proportionally to the dexterousness.

    homunculus
    descending tracts
    •pyramidal tract (corticos
    pinal tract ): from cortex t
    o the spinal cord directly;

    * extrapyramidal tracts: in
    directly through basal ga
    nglia, cerebellum, and n
    uclei in brain stem.
    descending tracts

    pyramidal tract
    descending tracts
    motor areas in the brain stem:
     vestibular nuclei: vestibulospinal tracts
     red nuclei: rubrospinal tracts
     reticular formation: reciculospinal tracts
    descending tracts
     functions:
    pyramidal tracts: synapse directly with motor neurons.
    rubrospinal tracts: distribute to spinal motor neurons supplyi
    ng distal limb muscles.
    both in fine motor control

    vestibulospinal tracts:
    reticulospinal tracts:

    in the control of balance and locomotion


    descending tracts
    the cerebellum:
    receives inputs from a wide variety of sources including:
    1 the vestibular apparatus;
    2 peripheral sensory receptors, especially muscle spindles
    and proprioceptors in joints;
    3 the visual and auditory system;
    4 the corticospinal pathway.

    and sends outputs to motor cortex (via the thalamus)


    to brain stem motor areas.

    playing a significant role in motor control.


    descending tracts
    the basal ganglia:
    receives input from :
     wide areas of cortex, including motor cortex;
     the thalamus, a relay station for sensory pathways;
     the substantia nigra in the midbrain.

    sends output to:


    motor cortex via the thalamus

    suggesting: have influence on the corticospinal output, especi


    ally in the initiation of movement and in controlling body po
    sture to allow for fine movements.
    descending tracts

    summary of the descending tracts

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