Discuss the role of the various descending motor pathways in the control of voluntary action. (Primates vs rodents and cats) Flashcards
What 2 systems can the descending motor pathways be divided into?
the pyramidal and the extrapyramidal
What is the pyramidal tract also know as?
The corticospinal tract
What is the pyramidal tract?
A direct pathway that originates from the motor cortex in the brain and extends to the spinal cord
What role does the pyramidal system play?
a pivotal role in the control of fine, precise movements, particularly those involving the hands and fingers
What is the pyramidal system characterized by?
its ability to facilitate voluntary motor control, with the large Betz cells in the primary motor cortex making significant contributions to the transmission of motor commands directly to the spinal cord
Pyramidel system in primates?
It is particularly well developed allowing their high degree of manual dexterity and the need for fine motor control for tool use etc
What does the extrapyramidal system involve?
Multiple indirect pathways that originate from various regions in the brain, including the brainstem, basal ganglia, and cerebellum
Extrapyramidal system and locomotion?
do not have direct contact with motor neurons but influence them indirectly; it modulates and refines movements initiated by pyramidal systems, playing a critical role in maintaining posture, balance, and coordinating gross, whole-body movement
Which system do rodents and cats use?
They rely more heavily on the functions of the extrapyramidal system due to their less developed pyramidal system
In what activities do rat and cats use the extrapyramidal system?
Running, climbing and jumping, use the extrapyramidal system for balance, coordination, and gross motor control
What is the 1st neural control of movement similarities in rodents, cats, and primates?
Both pyramidal and extrapyramidal systems involve the integration of sensory feedback for the refinement of movement
What is the 2nd neural control of movement similarities in rodents, cats, and primates?
Both systems exhibit a degree of plasticity, allowing for the adaptation and modification of motor commands based on experiences and learning
Why is plasticity important?
It is an essential feature of motor control, enabling the organisms to learn new motor skills, adapt to changing environments, and recover from motor deficits following injuries
Which tract is easiest to study in cats?
the rubrospinal tract as it is larger and more developed than in primates, it is easier to manipulate to look at the effect of posture and locomotion
What does the reticulospinal tracts do?
It acts as a rapid transmission to postural motor neurons that help to maintain balance during a movement eg. anticipatory postural adjustments
