Motor

Question 1

negative feedback tendon organs

Answer 1

○ Bicep flexor muscle contracts
○ Tendon organ fires via 1b afferents
○ In spinal cord activates excitatory interneurons to tricep flexor muscles and inhibitory interneurons to biceps
○ Terminates activity in bicep
○ Ankle extensor
○ Activate inhibitory interneurons back to extensors

Question 2

Reticulospinal

Answer 2

• General body orientation and simple motor patterns
• Inputs from motor cortex and cerebellum
• Mesencephalic locomotor region MLR
○ Shik et al, 1960s
§ Electrical stimulation of the midbrain elicited locomotion in cats
§ Low intensity = walking
§ Increased intensity = trotting, then galloping
○ MLR activates reticulospinal system to switch on movements
○ Signal to switch on CPG
§ MLR does not coordinate or organise movement
CPG interprets strength of stimulation to program appropriate output

Question 3

Rubrospinal

Answer 3

• Controls reaching and limb movements in mammals
  
  • Some direct inputs to motor neurons
  • Inputs from motor cortex and cerebellum
  • In humans - replaced by corticospinal tract, inputs to cerebellum

Question 4

Corticospinal

Answer 4

• Most important in mammals
	• Large lateral pathway
		○ Left
		○ Crosses in the brainstem
	• Ventromedial pathway
		○ Smaller
		○ Does not cross
	• Inputs to motor neurons are widespread in humans

Question 5

vestibulospinal

Answer 5

• Maintaining equilibrium

* Projections to limb extensor/antigravity muscles

Question 6

divide in spinal cord

Answer 6

• Medial pathways
		○ Cortico, vestibulo, reticulo, tectospinal
		○ Proximal muscles
	• Lateral pathways
		○ Cortico, rubrospinal
		○ Extremeties/distal muscles

Question 7

fast pathways - activation of CPG

Answer 7

mecenphalic region stimulated

reticulospinal tract

Question 8

long loop reflexes

Answer 8

corticospinal tract

lesions: spacticity
delays need to be eradicated

Question 9

long term modulatino

Answer 9

shape appropriate reflexes

infants and cerebral palsy - stretch reflex in both flexor and extensor

Question 10

varying output of CPG by supraspinal systems

Answer 10

slow pathways

Question 11

slow pathway function

Answer 11

change of motor output through functinoal reorganisation of the CPG through amines and peptides

decrease or increase output

large potential bcs many neuromodulators

eg amines increases during loom

Question 12

cerebellum role

Answer 12

comparing intended and actual movement
motor control
motor learning/ predictive motor control
non-motor functions
planning and execution of movements bcs of timing and scaling
feedforward input from motor cortex so dont need for muscle contraction

Question 13

vestibulocerebellum

Answer 13

head and axial movements

Question 14

spinocerebellum

Answer 14

integrates sensory info about ongoing movements from sc + efferent copy

Question 15

lateral cerebrocerebellum

Answer 15

planning and execution –> outputs via thalamus to basal ganglia

Question 16

otholith organ

Answer 16

head position signal : direction and position

Question 17

head position signal

Answer 17

utrice- horizontal
saccule - vertical

due to the directional sensitiivty of the hair cells

Question 18

semicircular canals

Answer 18

reflects angle of head rotation