Flashcards in Lecture 12: Contributions of Cerebellum & Basal Nuclei to Motor Function I Deck (116)
What does the primary motor cortex (area 4) signal?
Motor neurons to contract skeletal muscle fibers.
What tract does the primary motor cortex signal via?
Via the corticospinal (pyramidal tract) tract.
What are the executed commands of the primary motor cortex preceded by?
Extensive processing by cerebellum and basal nuclei.
What does the premotor cortex (area 6) plan?
Movements based on sensory and visual cues.
What does the supplementary motor area (area 6) function to do?
Retrieves and coordinates memorized motor sequences.
Which cortex retrieves and coordinates memorized motor sequences?
supplementary motor area (area 6)
Which cortex plans movements based on sensory and visual cues?
pre-motor cortex (area 6)
Which cortex signals motor neurons to contract skeletal muscle fibers?
primary motor cortex (area 4)
Which cortex provides most of the activating signals to the spinal cord?
motor cortex system
True or False:
Cord patterns are mainly determined by heredity and are "hard wired".
What does the motor cortex system issue?
Sequential and parallel commands that initiate various cord patterns.
List basic functions of the cerebellum.
- NOT essential for locomotion
- helps sequence motor activities
- monitors and makes corrective adjustments to motor activities while they are being executed
- compares actual movements with intended movements
- aids cortex in planning next sequential movement
- learns by its mistakes
- functions with spinal cord to enhance the stretch reflex
- functions with brain stem to make postural movements
- functions with cerebral cortex to provide accessory motor functions
- turns on antagonist at appropriate time
- helps program muscle contraction in advance
- functions mainly when muscle movements have to be rapid
What does the cerebellum play a major role in?
Timing of motor activities and in rapid, smooth progression from one muscle movement to the next.
What does removal of the cerebellum cause?
Body movements to become highly abnormal.
True or False:
Electrical excitation of the cerebellum does not cause any conscious sensation and rarely causes any motor movement.
What 3 lobes is the cerebellum anatomically divided into?
> Anterior Lobe
> Posterior Lobe
> Flocculonodular Lobe (associated with vestibular system)
What are the two hemispheres of the cerebellum separated by?
*each hemisphere is divided into an intermediate zone and a lateral zone*
What zones are the two hemispheres of the cerebellum divided into?
intermediate zone and lateral zone
What lobe of the cerebellum is evolutionarily the oldest?
What and where is the vermis; with what functions is it associated?
> the vermis separates the hemispheres of the cerebellum
> vermis -> location for control functions for muscle movements of the axial body, neck, shoulders, and hips.
What does the intermediate zone control?
Concerned with controlling muscle contractions in the distal portions of the upper and lower limbs, especially hands, feet, fingers, and toes.
What is the lateral zone associated with?
Associated with cerebral cortex with planning of sequential motor movements.
Does the cerebellar cortex have 6 layers?
No - only 3
What are the characteristics of the cortex of the cerebellum?
- like the cerebral cortex, this is gray matter and consists of multiple layers of cells, dendrites, and synapses.
- consists of transversely arranged narrow gyri called folia
What do the intracerebellar nuclei of the cerebellum make up?
Make up an inner layer of gray matter and include the following pairs of nuclei:
What would lesions in the dentate nuclei, emboliform nuclei, and globose nuclei cause?
**ataxia is abnormal movements of the limb, especially distal part of limb**
What would a lesion in the fastigial nuclei cause?
Where do fibers from the dentate nuclei, emboliform nuclei, and globose nuclei project to?
Which intracerebellar nuclei are related to limb musculature and fine manipulative movements?
- dentate nuclei
- emboliform nuclei
- globose nuclei