Module 4 Lecture 4.1-4.6 Flashcards
What are the 3 subareas of the Motor Cortex?
- PRIMARY MOTOR CORTEX
- Fine motor movement elicited by stimulation. - PREMOTOR AREA
- Stimulation results in movement of muscle groups to perform a task.
3.SUPPLEMENTARY MOTOR AREA
- Simulation often elicits bilateral movements.
What motor area is involved in coordinating the sequential movements of the legs and arms while walking and running?
Supplementary Motor Area
Writing typing, buttoning clothes are examples of motor functions controlled by the?
Primary Motor Cortex
Which motor area is involved in coordinating the muscles of the arms and shoulders to move and catch a baseball?
Premotor Area
What are some examples of Primary Motor cortex functions?
HIPS, LEGS, TRUNK, ARMS, FEET, FINGERS, NECK, THUMB, LIPS, VOCALIZATION, JAW TONGUE, SWALLOWING/CHEWING
What are some examples of Supplementary and Premotor Areas?
HAND SKILLS, HEAD ROTATION, CONTRALATERAL EYE MOVEMENTS
BROCA’S AREA
closely associated with cortical areas that control the appropriate respiratory function for speech. DAMAGE TO THIS AREA WILL CAUSE DECREASED SPEECH CAPABILITY.
The Corticospinal tract carries movement-related messages from the brain to the muscles involved. Imagine you are squeezing your hand, sort the steps of the descending Corticospinal tract pathway to cause that motor effect. The first and last steps are given (i.e., #1 would start where the signal originates in the motor cortex and #9 would finish with the effector muscles being stimulated).
- Motor Cortex
- Synapse with Gray Matter
- Midbrain
- Pons
- Pyramidal Decussation
- Synapse with Betz Cells
- Lateral/Ventral Corticospinal tract fibers
- Lower motor neurons
- Muscle
DEFINE BETZ CELLS
Known as “Giant Pyramidal Cells” :primary neural cell type in the Corticospinal tract. (34,000) They are pyramidal spinal cord neural connections for vision-guided motor function and cognition. They also send short collateral axons back to the cortex to sharpen boundaries of the excitatory signal by lateral inhibition on adjacent cortical regions.
Define Cortical Motor Signal Transmission
Provides information for discrete, detailed movements directly from the cortex to the spinal cord, whereas signals from the lower brain areas are communicated indirectly by helping to prevent unwanted muscle contractions from competing with voluntary movements.
Define the 2 pathways of the Cortical Motor signal?
- DIRECT PATHWAY (corticospinal tract): excitatory and is in charge of the initial part of the movement)
- INDIRECT PATHWAY (signals to basal ganglia, cerebellum, and brainstem nuclei): is inhibitory and prevents unnecessary movements).
__________ is essential for motor control?
Sensory Feedback
What three things tunes muscle movement?
Sensory feedback from muscle spindle, tactile receptors, and proprioceptors.
LESIONS OF THE PRIMARY MOTOR CORTEX?
(Remember contains giant Betz-Cells important for fine motor control) -Loss of voluntary control of discrete movement of the distal segments of the limbs. LESIONS HERE CAN CAUSE VARYING DEGREES OF PARALYSIS IN WHICH YOU CAN STILL GET GROSS MOTOR CONTRACTION, BUT THE ABILITY TO CONTROL FINE MOVEMENTS WOULD BE GONE.
“gate keeper for motor movement”Muscle spasticity from loss of inhibitory input from accessory areas of the cortex that inhibit excitatory brainstem motor nuclei. LESIONS OFTEN RESULT IN SPASMS THAT OCCUR IN MUSCLES ON THE OPPOSITE SIDE OF THE BODY. (parkinson’s and huntninton disease disruption)
BASAL GANGLIA
Loss of control of swallowing, clapping, and kissing are results of?
Lesions in the Primary Motor Cortex
Define Reticular Nuclei Functions
support the body against gravity through the involvement of muscles of the spinal column and extensor muscles of the leg.
EXCITE THE ANTIGRAVITY MUSCLES. They have a high degree in natural excitability. When opposed they cause powerful excitation of the antigravity muscles.
PONTINE RETICULAR NUCLEI:
INHIBIT ANTIGRAVITY MUSCLES. Inhibitory signals are sent to the antigravity muscles through the medullary reticulospinal tract. They receive collateral input from the corticospinal tract, the rubrospinal tract, and other motor pathways to activate the inhibitory action of the medullary reticular nuclei and counterbalance the signals coming from the pons.
MEDULLARY RETICULAR NUCLEI
What are the three main parts of the vestibular apparatus and define each part?
- SEMICIRCULAR DUCTS/CANALS: provide sensory input about rotational movement of the head
- UTRICLE: responds to movements of the head oriented horizontally (sidways and lateral displacements)
- SACCULE: respnds to movements of the head oriented vertically (up and down backwards-forward)
Define the Macula?
-Within the Utricle and Saccule sensory organs detect the orientation of the head with respect to gravity.
-hair cells provide information about linear acceleration and position of the head with respect to gravity
True or False: All 3 sensory organs provide spatial orientation and movement information to the brain about the head’s position in space?
True
What is the Vestibular Apparatus made of?
- Bony Labyrinth-from the inside to the outside its bathed in perilymph fluid which separates the bony from the interior membranous labyrinth.
- Membranous Labyrinth: Inside includes endolymph fluid.
What are the sensory cells for the vestibular system?
Hair Cells
