5b - Motor Systems & Action Flashcards
what is the function of the basal ganglia?
- receive major input from the cerebral cortex
- project back to cerebral cortex via thalamus
what are the 4 neural circuits that involve the basal ganglia?
- motor loop
- occulomotor loop
- prefontal loop
- limbic root
what is the motor loop related to?
movement
what is the occulomotor loop related to?
eye movements
what is the prefontal loop related to?
decision making
what is the limbic root related to?
emotions
what does the basal ganglia contribute to movement?
- assist in motor learning
- responding to rewards
- involved in motor planning
- assists in controlling muscle force, speed and size
- determine which limb trajectory is most efficient
def: modulates the actions of the spinal motor circuits
the brainstem
what are the 2 pathways that the brainstem project to the spinal cord in?
medial and lateral
def: parts of the basic postural control system, controls the axial muscles and proximal limb muscles
medial brainstem pathway
what descending pathways does the medial brainstem pathway include?
- vestibulospinal
- reticulospinal
- tectospinal
def: concerned with goal directed limb movements and predominantly control muscles of the limbs
lateral brainstem pathway
what descending pathway does the lateral brainstem pathway include?
rubrospinal tract
def: reticular formation, maintains posture and maintains muscle tone, mainly involved in extensor muscles
reticulospinal pathway
def: vestibular nuclei, controls posture and balance, affects orientation of head and body, involved in anti gravity muscles
vestibulospinal pathway
def: superior colliculus, coordinates head and eye movement
tectospinal pathway
def: red nucleus, excitatory influence on motoneurons innervating proximal upper limb flexors
rubrospinal pathway
where is the region in the brain that initiates walking?
- in the brain stem
- called the Mesencephalic locomotor region (MesLr)
def: initiates walking, connects to the reticular formation, triggers the CPG
Mesencephalic Locomotor Region - MesLr
def: integrates information that it receives from many locations around the body, sends this location to the motor planning areas and descending tracts
cerebellum
the _______ receives the sensory feedback copy, called the efference copy, and compares it to the actual received feedback
cerebellum
the _______ acts with the cerebral cortex to produce skilled movements by coordinating the activities of groups of muscles and also makes muscles smooth and activates muscles at the same times
cerebellum
what are the 3 general zones of the cerebellum?
- vestibulocerebellum
- spinocerebellum
- cerebrocerebellum
def: receives input from the vestibular nuclei regarding neck proprioception and visual input, projects back to vestibular nuclei, is located inside the cerebellum
vestibulocerebellum
def: contains the vermis and intermediate cerebellar hemisphere, receives input related to spinocerebellar tracts, medial area
spinocerebellum
def: contains lateral cerebellar hemispheres, receives input from cortical areas, projects back to cortical areas via the dentate nucleus
cerebrocerebellum
what are the 2 hemispheres within the spinocerebellum
vermis and intermediate cerebellar hemisphere
what does the vermis use to connect to the brainstems descending pathways and which pathways?
- the fastigial nuclei
- connects to the descending medial tracts
what is the name of the cerebrocerebellar hemisphere?
lateral hemishphere
where does the lateral hemisphere project to and for what function?
- projects to cortical areas for motor planning
where does the vestibulocerebellum get its info from?
from visual receptors and neck proprioception
where does the vestibulocerebellum project to and for what function?
via the vestibular nuclei and projects towards areas involved in head and body orientation
def: problems with trajectory or placement of body parts during movement
dysmetria
def: abnormalities with rapid alternating movements, deficits in the rate of alternation or completeness of the motor sequence
dysdiadochokinesis
def: coordination problem, will walk with a wide base of support and deviate from the path
gait ataxia
what structure has these functions:
- involved in planning and online control of movement
- integrates sensory information that comes from different sensory modalities
- areas of space can be described through others sensory systems rather than just eyes
- plays a role in working spatial memory and identifying oneself in space
posterior parietal cortex (PPC)
what are the 5 suborganizations of the PPC?
- parietal eye field
- parietal arm field
- parietal grasp field
- parietal face field
- parietal foot region
what is the supplementary motor area involved in?
- movement sequences from memory
- important to bimanual movements
- has a role in learning
what is the premotor cortex involved in?
- involved in the selection of movement from external cues
- involved in planning, reaching, and grasping movements
- role in decision making
def: connects to alpha motor neurons to activate muscles, assist in adapting movements based on conditions, relates to muscle force, determines direction of movement
primary motor cortex (M1)
how can we determine the direction of movement if neurons activate during all directions of motion?
we sum up the motion vector that is associated
