Motor learning and neurological syndromes

Question 1

Simple motor pathway

Answer 1

Motor cortex of the brain

Upper motor neurone

Lower motor neurone

Muscle

Question 2

Upper and lower motor neuron

Answer 2

Upper: from motor nerve cells

Lower: from spinal cord

Question 3

High level

Answer 3

Strategy

Association areas of neocortex and basal ganglia

Question 4

Middle level

Answer 4

Tactics

Motor cortex and cerebellum

Question 5

Low level

Answer 5

Execution

Brainstem and spinal card

Question 6

The pyramidal or corticospinal tract

Answer 6

Only cortical tract to directly synapse with motor neurons

90% fibres crossed in lateral CST but individual variation

Question 7

Rubrospinal tract

Answer 7

Unclear to what extent this pathway is involved in humans

Predominantly innervates the flexor muscles in the upper limbs

Question 8

Vestibulospinal tract

Answer 8

Originates in vestibular nuclei of medulla which relay sensory info from vestibular labyrinth in inner ear

Question 9

Medial vestibulospinal pathways

Answer 9

Prohexts down spinal cord and activates cervical spinal circuits that control neck and back muscle guides so guide head movements

Helps to keep eyes stable as body is moved

Question 10

Lateral vestibulospinal pathways

Answer 10

Projects ipsilaterally as far down as lumbar spinal cord

Helps maintain upright and balanced posture by facilitating extensor motor neurones of the legs

Question 11

Tectospinal tract

Answer 11

Originates in superior colliculus in midbrain which receives direct inputs from retina

Used to construct map of world around us

Allows us to direct head and eyes to move so appropriate point of space is imaged on fovea

Question 12

Reticulospinal tract

Answer 12

Runs from brainstem

Reticular formation is just under cerebral aqueduct and fourth ventricle

Descends in 2 pathways (pontine and medullary) which facilitate extension of the limbs

Question 13

Descending pathways

Answer 13

Tectospinal and medial vestibulospinal
- control head and neck movements

Lateral vestibulospinal and reticulospinal
- activate extensor muscles in arms and legs

Rubrospinal
- activates flexor muscles in arms

Question 14

Damage to motor cortex and corticospinal tract- humans

Answer 14

Typical posture
- some preserved upper limb flexion and lower limb extension

Increased tone, brief reflexes, extensor plantar/ babinski reflex, clonus

Question 15

Middle cerebral artery occlusion

Answer 15

Proximal lesion affects internal capsule

Complete hemiparesis

Distal lesion may spare leg area of motor cortex

Question 16

Anterior cerebral artery stroke

Answer 16

Supplies medial part of frontal lobes including area of motor cortex

Leg paresis > arm paresis

Frontal sings (e.g. abulia)

Question 17

Abulia

Answer 17

Loss or impairment of the ability to make decisions or act independently

Question 18

Seizure ‘March” (Jacksonian seizure)

Answer 18

Partial onset simple motor seizure becoming secondarily generalised

Strongly associated with structural abnormality in or close to motor cortex

Question 19

Posterior parietal cortex

Answer 19

Area 5- somatosensory afferents

Area 7- Visual pathway afferents

Mental body/ environment image

Damage results in neglect

Exploratory movements

Question 20

Premotor area

Answer 20

Importance in control of visually guided movements

Receives inputs from cerebellum and is involved in planning movements based on external cues

Involved in control of postural and proximal limb muscles

Question 21

Types of apraxia

Answer 21

Ideational

Ideomotor

Question 22

Ideational apraxia

Answer 22

Unable to report the sequence

Question 23

Ideomotor apraxia

Answer 23

Unable to use the tool

Question 24

Function of basal ganglia

Answer 24

Positive feedback loop with the cortex to select wanted movements and deselect unwanted movements

Question 25

Funciton of cerebellum

Answer 25

Coordination of muscles in order to make smooth movements

Balance

Motor learning