Module 3 Lecture 2 Flashcards
(94 cards)
1
Q
How the brain influences the activity of the
spinal cord
A
the central motor system
2
Q
The central motor system is arranged as a
hierarchy of control levels with the __________
at the top and the __________ at the bottom
A
forebrain
spinal cord
3
Q
Types of Movements
A
- rhythmic
- reflexes
- voluntary
4
Q
__________ – “simple” neural circuit resides in
spinal cord or brain stem
A
Reflexes
5
Q
_________ - includes a central component that
regulates spinal cord oscillatory circuit
A
Rhythmic
6
Q
__________ - requires ‘higher’ levels such as
cortex, basal ganglia, cerebellum
A
Voluntary
7
Q
___________: motor systems are organized by levels
A
Hierarchical control
8
Q
________________: more than one pathway may be active at the same time
A
Parallel control
9
Q
____________: The cerebral neocortex has information—
based on vision, audition, somatic sensation, and
proprioception—about precisely where the body is
in space.
A
Strategy
10
Q
Filtered through the ___-________ and back
to the ___________ until a final decision is made,
A
basal ganglia
cortex
11
Q
during the ____________ stage, The motor areas of cortex and the cerebellum issue instructions to the spinal cord
A
tactics
12
Q
___________ are all involved in Coordination
of muscles:
shoulder,
elbow…
A
Cervical region
Thoracic and lumbar region
Brain stem
13
Q
• _____________
– Association area of neocortex
– Basal ganglia
A
High level (strategy)
14
Q
_____________
– Motor cortex
– Cerebellum
A
Middle level (tactics)
15
Q
____________
– Brain stem
– Spinal cord
A
Lower level (Execution)
16
Q
Descending Spinal Tracts
A
– The ventromedial pathways
– The lateral pathways
17
Q
_____________
• Involved in the control of posture and are under brain
stem control
A
– The ventromedial pathways
18
Q
________________
• Are involved in voluntary movement of the distal
muscles
• Under direct cortical control
A
– The lateral pathways
19
Q
__________
– Muscles of the trunk
– To maintain posture
A
Axial muscles
20
Q
____________
– Muscles of the shoulders, elbows, thighs, and knees
– Locomotion
A
• Proximal muscles
21
Q
_________________
– Muscles of the hands, feet, and digits
– Manipulations of objects
A
• Distal muscles
22
Q
The Lateral Pathways
A
- Corticospinal tract
* Rubrospinal tract
23
Q
_______________ originates in the
neocortex (about 2/3 of axons originate from
areas 4 and 6 of the frontal lobe-motor
cortex)
A
Corticospinal tract
24
Q
the remainder neurons derive from the________________ of the parietal lobe
A
somatosensory area
25
__________________:
Parallel the corticospinal tract
Receives input from
frontal cortex
the rubriospinal tract
26
What is the path of rubriospinal tract
spinal cord -> medulla -> midbrain-> rednucleus
27
Lesions studies of the lateral pathways from
the work of Lawrence and Kuypers in the 60s
showed that
– Monkeys are unable to do fractional movements
– Voluntary movement were slower and less
accurate
– Monkeys could sit upright and stand with normal
posture
28
• Lesions of the corticospinal tract alone caused
| – Movement deficit as severe as the __________
lateral tract lesion
29
___________
– The only permanent deficit was some weakness in the
distal flexors and inability to move the fingers
independently
• Recovery
30
• Lesion of the rubrospinal tract _______
reversed recovery
31
________________
• Originate in the brain stem and terminate in
the spinal interneurons that control the
proximal and axial muscles
The Ventromedial Pathways
32
The Ventromedial Pathways (4)
– Vestibulospinal tract
– Tectospinal tract
– Pontine reticulospinal tract
– Medullary reticulospinal tract
33
The Ventromedial Pathways (4)
– Vestibulospinal tract
– Tectospinal tract
– Pontine reticulospinal tract
– Medullary reticulospinal tract
34
```
_____________ Use sensory
information about
balance, body
position, and the
visual environment
to reflexively
maintain balance
and body posture.
```
Ventromedial Pathways
35
______________ control neck and back
muscles and guide head
movement. Stability of the head
is important
Vestibulospinal tract
36
Control the
posture of the
head and neck
Vestibulospinal tract
37
The The vestibularspinal tract____________ down
| to cervical regions
Bilaterally
| projection
38
vestibular spinal tract Not shown Lumbar region projection that facilitating
extensor motor neurons of the legs
39
vestibular spinal tract Receives information from
| ___________________
the inner ear via CN VIII
40
_____________: Receives direct input from
the retina, visual cortex,
somatosensory cortex
tectospinal tract
41
Orienting response that directs the
head and eyes to move so that the
appropriate point of space is __________
imaged on the fovea.
42
The tectospinal tract Control muscles of the
neck, upper trunk and
| shoulders
43
trace the tectospinal tract
spinal cord -> medulla ->superior colliculus
44
where does the tectospinal tract dessicate
cervical region
45
The Pontine and the Medullary
| Reticulospinal Tract Originates mainly from the
reticular formation
46
The Pontine and the Medullary
| Divided into two parts:
– The medial pontine reticulospinal Tract
| – The lateral medullary reticulospinal tract
47
Pontine RST enhances the antigravity reflexes of the
spinal cord
48
Medullary RST liberates the antigravity muscles from
| _________
reflex control
49
Making movements depends on
1- knowledge of where the body is in space
2-Where it intends to go
3-Selection of a plan to get there
50
Neurosurgeon
Mapping regions of the
brain
Electrical stimulation
51
Weak stimulation
to area 4 would
illicit movement on
the opposite side
52
Two other areas
| in the frontal lobe
(area 6)
53
PMA connects with reticulospinal tract that innervates
proximal motor units
Area 4: Somatotopy
Area 4 is now often referred to as primary motor cortex or M1
54
Area 4: Somatotopy
| Area 4 is now often referred to as _____________
primary motor cortex or M1
55
SMA and PMA play a major role in the
| planning of movement
– Distal musculature
56
• Cells in the SMA increase their discharge a
| second before ________________
the execution of movement
57
```
Some neurons in area 6 respond not only
when movements are executed, but also
when the same movement is only imagined
(mentally rehearsed)
• They also fire when the movement is
observed
• These neurons found in the PMA are called
_________________
```
mirror neurons
58
Area 4 has strong connections with the __________ and is called the ____________
spinal tracts
| Motor strip
59
The Input-Output Organization of M1
Can synapse on spinal interneurons as well as lower motor neuron
60
Recordings from M1 neurons in behaving
animals have revealed that a burst of activity
occurs immediately before and during a
voluntary movement. This activity appears to encode two aspects of the movement:
force and direction
61
what are the three major areas of the brain for responsive movement
- cortex
- basal ganglia
- cerebellum
62
All movement goes through
spinal cord
63
_________ are groups of axons in the central nervous system
tracts
64
cortex commands which pathways
lateral pathways
65
brain stem commands which pathways
ventromedial pathways
| postural muscles
66
what is the most important pathway which originates In cortex to spinal pathway
corticospinal tract
67
_________ is much smaller and is responsible for distal muscle. Is involved in distal studies
The rubriospinal tract
68
__________ Earlier microstimulation studies
The Work of Apostolos Georgopoulos
69
Individual M1 neurons have broad functioning allowing them to fire ___________
from many directions
70
-Move joystick towards a light whose position varied randomly
-Movement direction was encoded instead by the
_________________
collective activity of a population of neurons
71
The coding of movement of M1 neurons
The neurons in the M1 have a preferred movement with higher force; however, they still fire at other angles
72
During the coding of M1 neurons
both are firing. but some at lower frequency
73
```
The Coding of Movement in M1
• These studies suggest three important
conclusions about how M1 commands
voluntary movement:
– (1) much of the motor cortex is ________________ ___________________
```
active for every
| movement
74
The Coding of Movement in M1
• These studies suggest three important
conclusions about how M1 commands
voluntary movement:
– (2) the activity of each cell represents a single
_____________________
“vote” for a particular direction of movement
75
The Coding of Movement in M1
• These studies suggest three important
conclusions about how M1 commands
voluntary movement:
____________ registered by
each cell in the population
tally (and averaging) of the votes
76
The parietal lobes are extensively interconnected with regions in the _______________
anterior frontal lobes (prefrontal cortex)
77
Area 3b is the ________________
– (1) it receives dense inputs from the VP nucleus of
the thalamus
– (2) its neurons are very responsive to
somatosensory stimuli (but not to other sensory
stimuli)
– (3) lesions here impair somatic sensation
– (4) when electrically stimulated, it evokes somatic
sensory experiences.
primary somatic sensory cortex
78
primary somatic sensory cortex:
it receives dense inputs from the VP nucleus of
the_____________
thalamus
79
primary somatic sensory cortex:
its neurons are very responsive to
________________(but not to other sensory
stimuli)
somatosensory stimuli
80
primary somatic sensory cortex
| lesions here impair ___________
somatic sensation
81
primary somatic sensory cortex
| when electrically stimulated, it evokes____________
somatic sensory experiences.
82
Areas 1 and 2 receive dense inputs from area 3b. The
projection from 3b to area 1 sends mainly
texture information, while ________________
the projection
| to area 2 emphasizes size and shape.
83
Area 3a also receives a
| dense input from the _______________________
thalamus; is concerned
with the sense of body
position rather than
touch.
84
PET studies: changes in_____________
– Subjects asked to perform series of finger
movements (areas 5, 7, 6, and 4)
– Subjects asked to think about the movement (area
6)
blood flow
85
The larger the population of neurons
representing a type of movement, the finer
the possible control.
– Hands movements and the muscles of facial
| expression
86
• Fine movements of other muscles can be
| learned with ___________
experience
87
• In one series of experiments, Donoghue and Sanes used cortical
microstimulation in rats
• They mapped the regions of M1 that normally elicit movements of
the forelimb, facial whiskers, or muscles around the eye.
• Then they cut the motor nerve that supplies the muscles of the
snout and its whiskers
• They found that regions of M1 that had evoked whisker
movements now would elicit either forelimb or eye movements
• The motor map had been reorganized.
• They speculated that similar types of cortical reorganization might
provide a basis for learning fine motor skills
The Malleable Motor Map
88
```
They cut the motor
nerve that supplies
the muscles of the
snout and its
whiskers and found
that regions of M1
that had evoked
whisker movements
now would elicit
```
either forelimb or
| eye movements
89
Map represents
motor cortex from a
normal rat
```
Used cortical
microstimulation form
M1 cells that normally
elicit movements of the
forelimb, facial
whiskers, and muscles
around the eye
```
90
____________= a set of rules by which a process
can be carried out
• Often refers to a calculation that will be
performed by a computer
• Starting to be created for neural control of
movement: – Breakthrough studies where paralyzed patients move robotic arm by their own thoughts
Algorithm
91
In Conclusion
• To initiate a movement, a lot of neurons are
involved chorus of activity to the spinal motor
neurons that generate the ____________
the precise movements
| necessary to propel the baseball accurately
92
Neuronal Correlates of Motor Planning
| • Ready
– Depends on activity of the parietal and frontal
| lobe (prefrontal cortex)
93
• Set
– SMA and PMA
– Movement strategies are derived and held for
execution
94
• Go
– MA1
