Cortical Motor Control
This area is critical for the execution of voluntary movements
What is the Primary Motor Cortex?
Often called the "little brain," this structure is critical for error-driven motor learning
What is the cerebellum?
A hypokinetic disorder we discussed in class, characterized by difficulty initiating voluntary movement.
What is Parkinson's Disease?
This early neurosurgeon mapped the somatotopic organization of the precentral gyrus.
Who is Wilder Penfield?
This part of the premotor cortex is primarily involved in planning movements in response to external cues.
What is the premotor area (PMA)?
This corticostriatal loop facilitates movement by exciting the motor cortex.
What is the direct pathway?
A hyperkinetic disorder characterized by excessive, unwanted movements, associated with atrophy in the caudate nucleus.
What is Huntington's Disease?
The junction where an efferent motor neuron's axon terminal meets a muscle fiber.
What is the neuromuscular junction?
This part of the premotor cortex is involved in planning self-initiated and complex motor sequences
What is the supplementary motor area (SMA)?
This corticostriatal loop inhibits movement.
What is the indirect pathway?
Patient D.F. had a ventral stream lesion that caused this condition, impairing object recognition but sparing her ability to grasp objects appropriately.
What is visual form agnosia?
In the two-streams model of vision, this stream is known as the "what" pathway, or "vision-for-perception".
What is the ventral stream?
According to Goodale & Milner, this visual stream, which terminates in the posterior parietal cortex, is the "how" pathway, responsible for "vision-for-action".
What is the dorsal stream?
This structure is the key cortical input zone of the basal ganglia, consisting mainly of the caudate and putamen
What is the dorsal striatum?
In Parkinson's Disease, decreased dopamine results in an increased effect of this movement-inhibiting pathway.
What is the indirect pathway?
A term for brain organization where there is a correspondence between physical space and brain space, such as in retinotopy or somatotopy?
What is topographic organization?
Research by Graziano using longer stimulation trains in M1 suggested that the motor cortex is organized into these meaningful, whole-body actions like "defensive" or "hand-to-mouth" movements.
What are Ethological Categories of Movement?
The hyperdirect pathway provides a rapid "brake" for unwanted actions via signals from the Inferior Frontal Gyrus directly projecting to this subcortical target.
What is the subthalamic nucleus (STN)?
Patient V.K. had a dorsal stream lesion causing this condition, which impairs the ability to perform visually guided actions.
What is optic ataxia?
Georgopoulos and colleagues showed that the collective activity of M1 neurons could be averaged to create this, which accurately predicts movement direction.
What is the "population vector"?