Lecture 6: Motor System Flashcards
Prefrontal Cortex
a large frontal-lobe area anterior to the motor, premotor, and cingulate cortex, including dorsolateral, ventromedial, and orbitofrontal regions that receive projections from the dorsomedial nucleus of the thalamus
plays a key role in controlling functions such as planning and strategizing and in emotional behaviors
Premotor Cortex
frontal lobe areas 6, 8, and 44, lying immediately anterior to the motor cortex
houses a movement repertoire (lexicon) that recognizes others’ movements and selects similar or different actions
also called the supplementary motor cortex
Motor Cortex
area 4 of the frontal cortex
produces muscle movements
Mirror Neurons
cells in the primate premotor cortex that fire when an individual observes a specific action taken by another individual
the core mirror neuron system is transitive, responding to a wide range of actions that might be used to obtain a goal
the distributed mirror neuron system responds to intransitive actions, movements in which a goal is not present
Caudate Putamen
a large cluster of nuclei located beneath the frontal cortex
prominent structure of the basal ganglia
Dyskinesias
any disturbance of movement
Huntington Disease
a hereditary disorder characterized by chorea (ceaseless, involuntary, jerky movements) and progressive dementia, ending in death
Hyperkinetic Symptoms
involuntary excessive movements
symptom of brain damage
Tourette Syndrome
a disorder of the basal ganglia characterized by tics
involuntary vocalizations (including curse words and animal sound)
and odd, involuntary movements of the body, especially of the face and head
Hypokinetic Symptoms
difficulty in making movements
symptom of brain damage
Parkinson Disease
a disorder of the motor system that is correlated with a loss of dopamine in the brain and characterized by tremors, muscular rigidity, involuntary movements (akathesia), and changes in emotion and memory
Globus Pallidus (GPi)
the area of the basal ganglia involved in mediating motor activity
the inhibitory and excitatory pathways to the motor cortex converge in the GPi, which acts as a volume control to determine the strength or weakness of motor activity
Flocculus
a small lobe projecting from the ventral surface of the cerebellum that receives projections from the vestibular and so takes part in controlling balance
Corticobulbar Tracts
descending tracts from the neocortex to the lower brainstem that innervate facial motor neurons
Corticospinal Tracts
descending tracts from the neocortex originating in layer V of the cerebral cortex and ending in the spinal cord
also called pyramidal tracts
Lateral Corticospinal Tract
a pathway in the lateral spinal cord that carries information instructing movement
crosses over to the opposite side of the brainstem at the pyramidal protrusion
Anterior Corticospinal Tract
a pathway that carries instructions from the cortex to the spinal cord for the movement of the trunk
does not cross over to the opposite side of the brainstem at the pyramidal protrusion
Extensor Muscle
a muscle that acts to straighten a limb
Flexor Muscle
a muscle that acts to bend a limb at a joint
What are the functions of the motor system during hand movement?
- visual information required to locate target
- frontal-lobe motor areas plan the reach and command the movement
- spinal cord carries information to hand
- motor neurons carry message to muscles of the hand and forearm
- sensory receptors on the fingers send message to sensory cortex saying that the cup has been grasped
- spinal cord carries sensory information to brain
- basal ganglia judge grasp forces, and cerebellum corrects movement errors
- sensory cortex receives the message that the cup has been grasped
How is the cerebellum involved in the motor system in hand movement?
gets copy of signals
communicates to higher order systems for correction
What is the pathway used to plan motor actions?
- posterior cortex provides sensory information to the frontal cortex
- prefrontal cortex plans movement
- premotor cortex organizes
- motor cortex produces specific movements
Where does blood flow in the brain when completing a simple task like pushing a button?
blood flow increases in the hand area of S1 and M1 when participants use a finger to push a lever
some somatosensory and some motor activation
posterior parietal doesn’t need to be involved