Neural control of movement Flashcards
describe neurodevelopment of movement - what is the order of increasing complexity associated with each part of brain? [4]
- *1. pons 1-5 weeks,** (crawling on stomach)
- *2. midbrain, 4-13 months** (crawl hands and knees, hands open and close)
- *3. cortex 8- 96 months** (upright walk and cross pattern)
- *4. prefrontal cortex up to 25 years** (refined skills for performance)
descibe mechanism of monosynaptic reflex
descibe mechanism of monosynaptic reflex
- muscle spindles receptor are activated by tendon & muscle being stretched & causes contraction of extrafusal fibres
BUT: 4 distinct but interactive systems come into play here:
- lower motor neurons of monosynaptic reflex will modulate the activity of the reflex (e..g if thinking about reflex it will be reduced)
- upper motor neurons
- cerebellum
- basal ganglia
all voluntary movements rely on direct innervation from:
upper motor neuron
lower motor neuron
cerebellum
basal ganglia
thalamus
all voluntary movements rely on direct innervation from:
upper motor neuron
lower motor neuron:
cerebellum
basal ganglia
thalamus
describe the basic functions of
- LMN
- UMN
- cerebellum
- basal ganglia
in creating movement !
LMN: produce _muscle contraction_s via activation of motor neurons that synapse on a group of muscles fibres = motor units. strengh of contraction depends on no. of active motor units
UMN: produces voluntary movement - decides how many LMN are needed to contract to give correct response
Cerebellum: co-ordinate muscle movement, selects correct sequences (esp. for multijoint movements)
Basal ganglia: initiation and maintenence of movements, contains motor programs
Lower motor neurons:
- located where in the
a) spinal cord?
b) brain stem? - what symptoms can occur if you have damage to LMN? [5]
Lower motor neurons:
- located where in the
a) spinal cord: anterior horn / ventral horn
b) brain stem: cranail nerve nuclei - what symptoms can occur if you have damage to LMN? [5]
- *- flaccid paralysis**
- *- hypotonia (small amount of residual activity (that is tone) is gone))
- fasiciculations (small muscle twitching) - Ach receptors will spread out over surface of other muscle fibres - causes activation
- muscle atrophy**
upper motor neurons:
- where are cell bodies normally found?
- which 3 functionally distinct motor pathways does UMN use? what movements do they cause
upper motor neurons:
- where are cell bodies normally found?
- *primary motor cortex**
- which 3 functionally distinct motor pathways does UMN use?
corticospinal tracts: precise movements
rubrospinal tracts: gross movements, flexor movement
vestibulospinal and reticulospinal tracts: posture and balance, muscle tone and position of head and limbs
label the pathways of UMN x
A: lateral corticospinal tract. key !!
B; rubrospinal tract
C: reticulospinal and vestibulospinal tracts
D: ventral and corticospinal tracts
lateral corticalspinal tract controls WHAT? [1]
ventral corticalspinal tract controls WHAT? [1]
where does most of the corticospinal tract orginate from? [1]
lateral corticalspinal tract controls WHAT? [1]
distal musculature fine motor control
ventral corticalspinal tract controls WHAT? [1]
axial musculature (less important to know about)
where does most of the corticospinal tract orginate from? [1]
primary motor complex (although some comes from primary sensory cortex)
SOMATOTOPICALLY ORGANISED
at which point does the corticospinal tract decussate? [1]
at which point does the corticospinal tract decussate? [1]
spinomedullary junction
rubrospinal tract:
starts and finish points? [2]
recieves informatiom from? [2]
function? [2]
rubrospinal tract:
starts and finish points? [2]
- *start: red nucleus
finish: synapses on interneurons in spinal cord**
recieves informatiom from? [1]
reticular formation
function? [2]
faciliates reflex activity: facilitates flexors & inhibits extensors
which of the motor tracts overlap in spinal cord? [2]
which of the motor tracts overlap in spinal cord?
- corticospinal & rubrospinal tracts
vestibulospinal and reticulospinal tracts: (dont really need to know)
- vestibulospinal tract:
a) controls what ? [2]
b) damage results in? [1]
reticulospinal tract:
controls what? [1]
vestibulospinal and reticulospinal tracts:
- vestibulospinal tract:
a) controls: head eye coordination: maintains balance and upright posture
b) damage results in: ataxia
reticulospinal tract:
controls: excitatory and inhibit activity of LMN
approx. 1/2 of the UMN axons orginate from:
Brodmann’s area 1
Brodmann’s area 2
Brodmann’s area 3
Brodmann’s area 4
Brodmann’s area 5
approx. 1/2 of the UMN axons orginate from:
Brodmann’s area 1
Brodmann’s area 2
Brodmann’s area 3
Brodmann’s area 4 = aka primary motor cortex
Brodmann’s area 5
approx 1/2 of the axons of the corticospinal tract orginate from primary motor cortex - brodmann’s area 4. where else do they originate from? [3]
approx 1/2 of the axons of the corticospinal tract orginate from primary motor cortex - brodmann’s area 4. where else do they originate from? [3]
Brodmann area 6: supplementory motor cortex
Lateral premotor cortex
**Brodmann area 5: parietal cortex
Bromadnn area 1,2,3: somatosensory cortex
IMPORTANT TO RECOGNISE THAT ORIGINATES FROM ALL OVER BECAUSE KNOWLEDGE OF WHERE THE BODY IS IN SPACE, WHERE IT INTENDS TO GO AND THE SELECTION OF A PLAN REQUIRES MULTIPLE INPUT**
what are efference copy signals?
what is the function ?
efference copy signal: motor signal from the CNS to the periphery - an internal copy of an efferent movement producing signal that can be compared to the sensory input that results
Efference copies refer to internal duplicates of movement-producing neural signals. Their primary function is to predict, and often suppress, the sensory consequences of willed movements
function:
- reduces cognitive load by decreasing sensory sensory processing of the reafferent information
what is A?
efference copy signals
cerebellum:
- role in movement? [2]
- what does damage result in?
- what are the three parts of the cerebellum? [3]
cerebellum:
- role in movement? [2]
co-ordinates complicated multi joint movements
compares proprioception from movement with what you plan to do (does movement match with what you wanted to do) - what does damage result in? [1]
- *uncooordinated movements**
- what are the three parts of the cerebellum? [3]
vestibulo-cerebellum
spino-cerebellum
cerebro-cerebellum
what are the basal ganglia?
what are the five nuclei?
function?
Basal ganglia: or basal nuclei, are a group of subcortical structures found deep within the white matter of the brain.
5 nuclei:
- caudate
- putamen
- globus pallidus
- substantia nigra
- subthalamic nuclei
function:
- initation and maintence of motor actions - scale the strength of the response and organise correct sequence of activity
what is muscle tone due to? [1]
what is muscle tone dependent on? [1]
which structure detects tension in the tendon? [1]
muscle tone: due to a partial state of contraction in some fibres [1]. maintained reflexievly and adjuststed to the needs and posture of movement
dependent on: integrity of monosynaptic reflex.
detected by: golgi tendon organs: inhibition of alpha motor neurons causes muscle relaxation relieving tension in the muscle.
which group of muscles are important for maintaing postural stance? [1]
what is special about them compared to other muscles? [2]
which group of muscles are important for maintaing postural stance? [1]
antigravity muscles
what is special about them compared to other muscles? [2]
**more developed [1] and have greater tone [1]
REQUIRES INPUT FROM HIGHER LEVELS OF THE NS**
