From cortex to the muscles Flashcards
What brain structure links the sensory systems to the cortex?
Thalamus
What are the innate motor programs?
Swallow, vomit, cry, cough, sneeze
Development of motor system is under influence of…
Sensory system, vestibular system, muscle and skin receptors
What happens when a monkey is stimulated in layer 5?
Flick-like movement in contralateral side of body
What are the cortical motor areas
Premotor cortex, primary motor cortex, supplementary motor areas, cingulate motor cortex, (posterior parietal cortex)
What does the cingulate cortex take control over?
Represents highest level of motor control:
- Decisions on actions and their outcomes
- Abstract thinking, decision making
- Expected outcome of an action
What does the posterior parietal cortex take control over?
- Coordinate arm proprioception with the image of the hand
- Compute hand position in vision coordinates
- Compute target position in vision coordinates
How is the extra striate cortex involved in motor control?
The extra striate cortex refers to a group of regions in the occipital lobe which process visual information beyond V1.
- Via the dorsal pathway, info from V1 will go to the parietal cortex to detect where the object is. This goes via V2 –> MT (V5). The MT is specialized in tracking movement and motion detection (spatial vision)
What does the supplementary motor area do?
- Has topographical organization
- It controls BILATERAL contraction: bilateral grip, posture related movement, eye fixation, movements of head and eyes
What is the function of the premotor area?
- Its responsible for complex motor patterns
- Regulates target position in relation to hand position and coding of the appropriate movement
- Select movements with the context and the goal of the action
NOTE: has the same topographical organization as M1
In which motor area are mirror neurons mostly found and what is their function?
- In the premotor area
- Function is ‘action understanding’: interpret the goals and intentions of somebody elses action by mirroring the neural activity of performing that action yourself
Through which tract do M1 fibers occur and what do they do?
- Via pyramidal tract and cortico-spinal tract
- They put the appropriate movement in muscle activation patterns and sends them to the spinal cord
What does the firing of a single motor neuron signify?
Control of a specific pattern of movement
NOTE: does not control a single muscle
Which fibers mainly convey impulses to the cerebral cortex?
Thalamo-cortical afferent fibers
What do cortical efferent fibers do?
Carry impulses away from the cortex to lower centers
BONUS -
Match the cortical efferent fiber region with the right lower center:
Corticostriate - spinal cord
Corticopontine - basal ganglia
Corticobulbar - cerebellum
Corticospinal - brain stem
Corticostriate - basal ganglia
Corticopontine - cerebellum
Corticobulbar - brain stem
Corticospinal - spinal cord
What is the corona radiata and internal capsule?
Corona radiate consists of radial fibers that converge to form a fiber sheath –> internal capsule: fiber sheath that passes between the thalamus and basal ganglia (–> midbrain -> pons -> medulla oblongata –> spinal cord)
What are Betz cells?
Are big pyramidal neurons that send their axons to the spinal cord via the cortico-spinal tract from gray matter from M1
What are non-Betz cells
Neurons that go from PM and M1 to brainstem nuclei via cortical-bulbar tract
(for facial movement)
What is the Barrel cortex?
Part of primary somatosensory cortex in rodents. Each whisker has 1 ‘column’ in the cortex.
- Control over whiskers: motor cortex
- Detection of whiskers: somatosensory cortex
