Motor Control

Question 1

Activation of the motor neurons in the cervical spinal cord generate movements of ;
Activation of the motor neurons in the thoracic and lumbar spinal cord generate movements of ;

Answer 1

activation of the motor neurons in the cervical spinal cord generate movements of shoulder, elbow, wrist and fingers.
activation of the motor neurons in the thoracic and lumbar spinal cord generate movements of legs and involved in the postural adjustments.

Question 2

Premotor area and Supplementary motor area perform similar functions but on different groups of muscles.
SMA axons innervate ;
PMA axons innervate ;

Answer 2

SMA axons innervate distal motor neurons.

PMA axons innervate proximal motor neurons.

Question 3

Before making appropriate movement goals, we need have information about the position of the body in space. Where does this information come from ?

Answer 3

The mental body image is generated by somatosensory cortex (area 1, 2, 3) and by visual inputs to the posterior parietal cortex.

Question 4

Prefrontal cortex is involved in ;

Answer 4

Abstract thought, decision making, and anticipating the consequence of action.

Question 5

SMA (Supplementary motor area)

Answer 5

• Cells in SMA starts to fire action potentials before the movement is executed.
• SMA of the two hemispheres are closely linked via corpus callosum.
• Lesions in SMA are particularly problematic for tasks that requires the coordinated actions of the two hands.

Question 6

Apraxia

Answer 6

Selective inability to perform complex motor actions (not simple)

Question 7

SMA (supplementary motor area) PMA (premotor area)

Answer 7

In SMA and PMA, movement strategies are devised and held until they are executed.
SMA and PMA are important for planning of a movement and these regions get activated before the initiation of the movement.

Question 8

Mirror neurons are found in ;

Answer 8

Area 6, PMA / posterior parietal cortex (from victors’ lecture)

Question 9

Where does the SMA get its information from ?

Answer 9

1. Information from cortex (frontal cortex, prefrontal cortex, parietal cortex) goes into ;
2. Basal ganglia ; from basal ganglia info goes into ;
3. Ventral Lateral Nucleus of Dorsal Thalamus ; and from there info goes into ;
4. SMA
   Basically ;
   Cortex - basal ganglia - VL nucleus of dorsal thalamus - SMA
   Selection and initiation of willed movements.

Question 10

Basal Ganglia consists of ;

Answer 10

Caudate Nucleus , Putamen, Globus Pallidus (internal and external) and sub thalamic nucleus.
Substantia nigra is a midbrain structure but connected with basal ganglia.

Question 11

Direct Pathway of Basal Ganglia ;

Answer 11

For direct pathway ‘Putamen’ and ‘Globus Pallidus internal’ are important.

• Cortical cells excite the putamen.
• Putamen inhibits the globus pallidus internal (which is inhibitory for VL cells in thalamus). But it cannot inhibit it anymore.
• VL cells excites SMA.