Motor Flashcards
What is somatotopic organization?
Certain area of the primary motor cortex controls movement of a specific part of the body
True or false: the primary motor cortex is homotopically connected to the opposite hemisphere.
True; both sides are connected to the other side that controls the same thing
What do lateral tracts (in descending motor pathways) control?
Independent limb movement
What do ventromedial tracts (in descending motor pathways) control?
Automatic, gross movements of trunk and core; proximal limb stability; limbs involved in posture and walking
What are the lateral tracts?
Corticospinal tract, corticobulbar tract, rubrospinal tract
What are the ventromedial tracts?
Ventral corticospinal tract, tectospinal tract, vestibulospinal tract, reticulospinal tract
Where does the corticospinal tract originate and where does it end?
It originates in the cortex (primary and supplementary motor cortex), down to pyramids in medulla, and terminates in gray matter of spinal cord
What does the corticospinal tract control?
Primarily fingers, hands, arms, lower legs, feet, and toes
Where does the corticobulbar tract originate and where does it end?
Originates primary from primary and supplementary motor cortex; cross in medulla, terminates in cranial nerve
What does the corticobulbar tract control?
Primarily movement of face, neck, and tongue; some eye movements
Where does the rubrospinal originate and where does it end?
Originates in red nucleus, into dorsal column, and exits on the area of spinal cord according to which area of the body it controls
What does the rubrospinal tract control?
Proximal limb movements of forearm and hands, but not finger movements
Where does the ventral corticospinal tract originate and where does it end?
Originates primary from primary and supplementary motor cortex; divides in spinal cord and projects bilaterally
What does the ventral corticospinal tract control?
Controls trunk (core muscles) and upper leg movements; involved in posture, walking, balance
Where does the tectospinal tract originate and where does it end?
Originates in superior colliculus (in tectum), descends and exits through bilateral areas of spinal cord
What does the tectospinal tract control?
Controls trunk movements and coordinates them with head movements
True or false: the ventromedial motor pathway is a unilateral system.
False; it is a bilateral system; for its muscle groups, the R hemisphere will control both sides of the body
Where does the vestibulospinal tract originate and where does it end?
Originates from vestibular nuclei, bilateral exit through spinal cord to trunk
What does the vestibulospinal tract control?
Gets input from semicircular canals that give info about head alignment; important for posture, reflexes, and walking
Where does the reticulospinal tract originate and where does it end?
Originates from multiple areas: reticular formation, premotor cortex, amygdala, hypothalamus and basal ganglia; ends throughout brainstem
What does the reticulospinal tract control?
Controls autonomic functions: muscle tone, coughing, sneezing, respiration; also volitional movements such as walking
What is the motor association cortex?
Premotor and supplementary motor area; receives the highest level of integrated sensory info from the parietal and temporal multimodal sensory association areas
What is the supplementary motor area?
Involved in learning and programming of sequenced movements; when one movement serves as cue for the next movement
What is the pre-supplementary motor area?
Involved in initiating the intention of movement
What is the premotor cortex?
Involved in learning and executing complex movements that are guided by sensory input; important when sensory input is “arbitrary” i.e., not directly related to the movement
What is apraxia?
Preserved ability to move but impairment in complex execution of movements; can be movement of wrong part of limb, incorrect movement of correct limb, or correct movements in incorrect sequence
What part of the brain is almost always associated with apraxia?
L hemisphere lesions; L parietal or L frontal (plans to move); L frontal will also impair ability to comprehend gestures of others
What is the neostriatum?
The caudate and putamen; in the basal ganglia
What does the cerebellum influence?
Postural reflexes; rapid, skilled multi-muscle movements; modification/regulation of movements initiated in cortex; timing and sequencing of movements
What symptoms are produced by lesions in the cerebellum?
(dependent on area) rigidity, fragmented movement, impaired timing, ataxia
