Central Motor System 1 Flashcards
Motor Cortex
Controls volitional movement
Premotor Cortex
-Involved in the planning of actions
-Stimulation can cause complex movements (e.g. reaching)
-Sends most connections to the primary motor cortex
-Sends some connections directly to the spinal cord
Mirror Neurons
These neurons fire…
-when an action is performed
-when watching someone perform that same action
-Found in premotor cortex and somatosensory cortex
-Some argue that mirror neurons are key to speech perception
-Acoustics of speech are directly tied to the physical motion of the articulators
-Accurately perceiving speech may require using the percieved sound to determine the (unseen) articulator movement
–Motor theory of speech perception
Primary Motor Cortex
-Involved in generating actions
-Stimulation can cause simple movements
-Receives input from somatosensory cortex
-An area that controls muscles in one area often receives proprioceptive input from that same area
Cortical respresentation
-Motor functions are organized topographically
-The size of the cortical area for a body part is related to the precision of motor control
-Is plastic and experience-based
Motor Programs
-When you write your name in vastly different sizes, you are using different muscle groups
-Then end result looks the same but scaled
-The speed and acceleration of the hand movement is also scaled
-This is called motor equivalence
-This suggests planning occurs at an abstract level
-This also explains how we can deal with perturbations and other unexpected sensory information
Basal Ganglia
-Involved in the refinement of motor activities
–Compresses competing motor activity
–Regulates desired motor activity
–Contributes to learned complex movements (like speech)
-Signals pass from the motor cortex through the basal ganglia and back to the motor cortex
Nucleus Accumbens
-Central structure for reward
-Involved in addiction
Substantia nigra
-Major source of dopaminergic neurons
Dopamine
-Critical for reward/addiction
-Degeneration of these neurons lead to Parkinson’s disease
GABA
-Major inhibitory neurotransmitter
-Plays a central role in the inhibitory pathways for the basal ganglia
Major Loops
-The basal ganglia is a part of a number of major loops where signals are modified
-These loops refine motor actions
-The basal ganglia does not initiate motor action, it only modifies it
Complex motor learning
-Learning complex motor skills (like talking) requires basal ganglia involvement
-For learned complex motor skills the basal ganglia plays a regulating role
Direct Pathway
Excitatory (Inhibit inhibition)
Indirect Pathway
Inhibitory (inhibit inhibition of inhibition)
