Neuro final exam week 12 pt 3 (8&12-14) Flashcards
1
Q
Spinocerebellum Outgoing command to move sent to the cerebellum is called
A
Feed forward signal via the cerebro-olivary and olivocerebellar inputs.
2
Q
Function of the Vermis
A
Coordination of movement of axial & proximal limb musculature and Regulation of postural muscle tone.
3
Q
Sensory Inputs to the vermis come from which systems? PVV
A
Proprioception, Vision & Vestibular sensory systems.
4
Q
Damage in the spinal proprioceptive pathways result in
A
Sensory ataxia
5
Q
Symptoms of sensory ataxia include:
A
Near-normal coordination when the movement is visually observed by the patient, but marked worsening coordination when the eyes are shut Increased postural sway Difficulty standing with narrow base of support particularly with the eyes closed (Romberg sign)Uncoordinated gait
6
Q
True / false- The body is somatotopically mapped with separate somatopic maps on anterior and posterior lobes of cerebellum.
A
True
7
Q
The two homunculi formed on the lobes of CEREBELLUM are
A
Inverted images of one another
8
Q
On the cerebellar homunculi, Neck & trunk are distributed along the
A
Vermis
9
Q
On the cerebellar homunculi extremities are aligned
A
Along the paravermal cerebellar cortex
10
Q
5 afferent tracts that provide proprioceptive information into the spinocerebellum
A
Dorsal spinocerebellar tract (DSCT) Cuneocerebellar tract (CCT) Ventral spinocerebellar tract (VSCT) Rostral spinocerebellar tract (RSCT) Trigeminocerebellar projections
11
Q
Dorsal spinocerebellar tract (DSCT) arises from
A
Nucleus dorsalis (Clarke’s) in spinal segments T1 to L2 or L3
12
Q
Dorsal spinocerebellar tract (DSCT) Rise (path)
A
Ipsilaterally in dorsal lateral funiculus to enter thru inferior peduncle
13
Q
Axons of the dorsal spinocerebellar tract (DSCT) end- (homunculus)
A
In areas representing LE & trunk in anterior & posterior lobes
14
Q
Ventral spinocerebellar tract (VSCT) arises from (area of SC)
A
nuclei scattered in base of dorsal horn
15
Q
Axons of the ventral spinocerebellar tract (VSCT) Decussate to rise in
A
Peripheral lateral funiculus just ventral to contralateral DSCT
16
Q
Axons of the ventral spinocerebellar tract (VSCT) ascend thru
A
Medulla & pons to decussate again and enter thru superior cerebellar peduncle
17
Q
Axons of the ventral spinocerebellar tract (VSCT) end in (homunculus)
A
LE representation of anterior lobe and paramedian lobule
18
Q
What type of activity does both VSCT & DSCT have during gait stepping cycle?
A
Phasic activity
19
Q
DSCT cells driven by proprioceptive afferents
A
unconscious proprioception
20
Q
VSCT cells driven by descending motor commands
A
Efferent copy
21
Q
CCT axons from ACN enter the
A
Inferior cerebellar peduncle innervating areas representing primary afferents from upper extremity
22
Q
Cutaneous input enters cerebellum from neurons in
A
main cuneate nucleus – providing proprioceptive input from hands and fingers
23
Q
Primary afferents from UE proprioceptors ascend in which tract?
A
Fasciculus cuneatus
24
Q
Where does the cuneocerebellar tract (CCT) end?
A
Accessory (lateral) cuneate nucleus (ACN) of caudal medulla
25
CCT axons from ACN enter thru the
Inferior cerebellar peduncle innervating areas representing UE
26
CCT axons from ACN carry information from -MGJ
Muscle spindles, GTOs & joints
27
Rostral spinocerebellar tract (RSCT) arise from
Cells scattered thru cervical segments
28
Rostral spinocerebellar tract (RSCT) rise ipsilaterally thru
inferior cerebellar peduncle but evidence for contralaterally rising axons which enter thru superior cerebellar peduncle
29
Where does rostral spinocerebellar tract (RSCT) end? (homunculus)
Both LE & UE representations of ipsilateral anterior & posterior lobes of cerebellum
30
Trigeminocerebellar tract (TCT ) projection comes from cells in which nuclei (s)?
Mesencephalic Chief sensory and Spinal tract nuclei of CN V
31
Fibers of the Trigeminocerebellar tract (TCT ) projection enter thru (peduncle)
Superior and inferior cerebellar peduncles
32
Trigeminocerebellar tract axons end (homunculus)
Ipsilaterally in the posterior lobe area with face representation
33
Role of the cerebellum in many cognitive functions related to hearing: ALAAS
* Auditory processing
* Language processing & linguistic
* Auditory memory
* Abstract reasoning & solution of problems
* Sensorial discrimination & information processing operations
34
Other Inputs of Paleo (Spino)-cerebellum:
Visual & Auditory
35
Where do visual & auditory inputs end?
In same region as face representation in posterior lobe
36
Visual inputs provide sense of
Verticality & horizontality from the visual space for maintenance of upright stance
37
The cerebellum participates in many cognitive functions related to hearing:
Speech generation
38
Outputs from the cerebellum include both - IF
Fastigial and interposed nuclear outputs
39
Fastigial Nucleus Outputs include:
Vermal outputs to vestibular & reticular nuclei -project bilaterally to control axial muscles.
Vermal outputs projects to VL of the thalamus-
Function in control of proximal musculature during movement Providing proximal stability for distal mobility
40
What is Gait?
Voluntarily deployed movement Instinctual, not learned – stepping movements early in development Stepping patterns present at birth Operational synergies contained in spinal cord in the form of central pattern generators (CPGs) The person consciously modifies organized synergies based upon environmental demands
41
Gait is a function which integrates control of - C2BS
Cortical areas, Cerebellum Basal ganglia, and Spinal cord
42
Abnormalities of gait is seen when there is
Dysfunction of a variety of nervous system structures.
43
Cause of gait disturbances
a variety of non-neural causes
44
Ataxic Gait
Wide base of support with irregular/erratic weight shifts and velocity -cerebellar in origin
45
Parkinsonian gait SN
Slow, stiff, shuffling gait, no arm swing but can be a quick, short stepping (festinating gait)
46
Diplegic (spastic) gait CP
Often faster, ataxic, stiff leg, circumducted, adducted, hip & knees flexes, plantar flexion, foot drop, flexed arm posture with no swing
47
Hemiplegic (spastic) gait CS
Slow, stiff leg, circumduction, foot drop, flexed arm posture with no swing
48
Tabetic gait
The term comes from tabies dorsalis – syphilitic cell death of dorsal root ganglion cells but may be due to other conditions
49
Tabetic gait (sensory ataxia)
Wide base of support, high stepping (steppage), drop foot, irregular/erratic cadence, ataxia- due to peripheral nerve damage
50
Dyskinetic gait CSt
Rapid, fragmented movement intrusions, ataxia, dance like movement
51
Ideational apraxia CPO
Inability to organize single actions into a sequence for intended purpose- Loss of knowledge of the movement
52
Ideomotor apraxia SmG & SPL
Inability to translate the idea of the action into an appropriate motor program- Lack of proper sequencing of movement.
53
Kinetic apraxia PMC
A form of clumsiness, loss of hand and finger dexterity not due to paresis, ataxia, or sensory loss
54
Oral apraxia IGG
Inability to execute facial movements on command
55
Hemiplegic gait associated with.CS
Cerebral stroke
56
Parkinson’s disease associated with. SN
Cell death substantia nigra compacta
57
Diplegic gait associated with. CP
Cerebral Palsy
58
Oral apraxia associated with IFG
Damage of the inferior frontal gyrus continuous with Broca’s area
59
Kinetic apraxia associated with. PMC
Damage to pre-motor cortex
60
Ideomotor apraxia associated with SmG & SPL
Damage to supramarginal gyrus / superior parietal lobule
61
Ideational apraxia associated with C-PO
Cortical – no specific area but parieto-occipital area very important
62
Dyskinetic gait associated with damage toCSt
Basal nuclei – caudate or subthalamic nucleus
63
T / F- Reaching across midline is faster & more accurate than reaching on the same side
F slower & less accurate
64
How does loss of somatosensory input affect reaching?
Reaching problems experienced immediately after loss of sensation Skills return gradually but only for simple reaching movements New or complex movements are impaired
65
How does loss of somatosensory input affect grasp
Somatosensory input is essential for grip Loss of cutaneous sensation prevents control of slip of objects within grasp. Abnormal increase occurs in the force of muscles of grasp to compensate for lack of “slip” information. Elevated force of grip is often decreased over 20-30 sec & 7 of 10 subjects dropped objects at least once Both slowly adapting & fast adapting neurons in somatosensory cortex respond to slipping objects
66
Which cortex initiates the concept of reaching and grasping-
Supplementary motor cortex
67
Neural Basis of reaching and grasping involves
Posterior parietal cortex & premotor cortex.
68
Loss of somatosensory input & grasp
Somatosensory input is essential for grip Loss of cutaneous sensation prevents control of slip of objects within grasp Abnormal Increase in the force of muscles of grasp to compensate for lack of “slip” information. Elevated force of grip is often decreased over 20-30 sec & 7 of 10 subjects dropped objects at least once Both slowly adapting & fast adapting neurons in somatosensory cortex respond to slipping objects
69
There are two separate motor pathways for reaching and grasp. In an infant reaching occurs at ____ week, while grip appears after\_\_\_\_\_\_ week
1 week, 10 weeks.
70
Motor cortex neurons active in precision grip are \_\_\_\_\_\_\_in power grips
inactive
71
Which part of the cortex initiates the concept of reaching and grasping-
Supplementary motor cortex
72
Which gyrus provides the motivation to accomplish the act of reaching & grasping.
Anterior cingulate gyrus
73
T / F- Reaching tasks when standing requires less postural support than when sitting. Postural demands can effect speed accuracy of reaching tasks
False more postural support
74
Cortical area responsible for providing numerous descriptions of objects for manipulation & multiple strategies to grasp objects
The posterior parietal cortex
75
Two hypotheses in targeting distances
Joint angle hypothesis Distance point hypothesis
76
Joint angle hypothesis
Select proper joint angle to reach the point
77
Which part of the cortex helps with choosing the best strategies for reaching & grasping?
The premotor cortex
78
Motor cortex neurons active in precision grip are
inactive in power grips
79
Theories of Targeting
distance or location Both strategies are used depending upon the task and context
80
Distance programming theory
Individual perceives a distance to target and programs the activation of muscles at level & pattern to propel hand/arm that distance Most studies would suggest that: **Slow movements are accomplished by distance strategy**
81
Role of cerebellum in reaching & grasping
More active during reaching and grasp than just gripping an object
82
Ballistic movements are accomplished by
a combination of both distance & location strategies
83
Most axons from the globose & emboliform nuclei end in
VL nucleus of thalamus and project to motor cortex
84
The cerebellum plays a role in
Anticipatory postural adjustments for reaching tasks – particularly those for which the person had not been previously trained
85
T / F- Because of the shift of the center of mass in a reaching task, there is task dependence with the interaction between postural support and reaching tasks.
True
86
Two forms of grasping
Precision grip & Power grip
87
Precision grip
Grasping a pen or needle- mediated by the primary motor cortex with very specific activation of Individual cortical motor neuron projections
88
Power grip
Holding a hammer or climbing a rope- mediated by both cortical motor & noncortico motor projections
89
Neuroanatomical areas that control grasping
Visomotor transformations -mediated by the PPC and premotor cortex
90
T / F- Reaching tasks when standing requires less postural support than when sitting. Postural demands can effect speed & accuracy of reaching tasks
False more
91
Key elements to reach, grasp & manipulate tasks are:
Locating the target - also called visual regard
Coordination of eye and hand motions Reaching •
Translocation of arm & hand in space •
Postural support Grasping including grip & release
In hand manipulation of object
92
T/F - External support of trunk decreasing postural demands movements are faster & more accurate. Hence children supported in a shopping cart can seem to reach really fast to grab stuff off the shelf
True
93
Feedforward Control is necessary for
the anticipation of events & resultant actions based upon previous experiences. In a new task, Visual information updates previous experiences.
94
Steps of reaching and grasping: Step 1- Target Location which involves Eye-Head Coordination.
When object in peripheral vision sequence of events
Eye movement – shortest latency & begins before head movement
Head movement – EMG activation of neck musculature 20-40 msec BEFORE eye muscles but inertia of head \> eyes so eyes move first. Eyes focus on object before head stops moving – so eyes must maintain that position and focus as the head is still moving
95
Steps of reaching and grasping: Step 1- Target Location which involves Eye-Head Coordination
When vision of object needed, head moves 60-75% distance to target and the eyes complete the motion. However when greater accuracy needed full head eye simultaneous movement to target occurs
96
There are 3 distinct conditions in target location- CEL
Control of eye & head movement
Eye movement alone Locate in far periphery, eye, head & trunk movement together
97
Step 2- Visual Pathways & Movement – Parietal cortex
Focus on stable visual image with eye movement. Anticipate amount of eye & head movement and update brain’s representation of the visual field based upon anticipated movement. Eye “catches up” to the brain’s updated image through visual saccades - seen with the Parietal neurons firing 80 msec prior to visual saccades. Parietal neurons have corollary discharges to other brain regions- pre-motor cortex & frontal eye fields. Neurons driving both saccadic movements & UE movements are both located adjacent to UE 1° motor cortex in the frontal eye fields and pre-motor cortex respectively
98
Step 3- about Eye-Hand Coordination
Hand movements are more accurate when accompanied by eye movements. Increased gain & decreased latency of visual pursuit movements when hand follows the target. Linkage between hand and eye movement are through afferent copy or corollary discharge rather than proprioceptive feedback because it is too fast to rely upon feedback. Proprioceptive feedback does assist in accuracy of visual & manual pursuit Reach and the grasp. Point to an object - arm and hand is controlled as one unit. Reaching to grasp - hand is controlled independently of rest of arm
99
Two forms of Feedback used in reaching tasks VP
Visual & proprioceptive There is no clear evidence of which strategy used so probably a combination of the two strategies feedback
100
Proprioceptive
joint angle
101
Visual
point in space.
102
Location programming theory
Nervous system programs the relative activation of antagonistic muscles to move limb to a certain position in 3-D space
103
Ballistic movements are accomplished by
a combination of both distance & location strategies
104
Axons from globose and emboliform nuclei exit & decussate in\_\_\_\_\_\_\_ as\_\_\_\_\_\_andterminate in the\_\_\_\_\_\_ part of red nucleus. These axons activate the _____ and are also ____________ fibers
superior cerebellar peduncle, Cerebellorubral fibers, magnocellular, rubrospinal pathways, cerebellothalamic
105
Most axons from the globose & emboliform nuclei end in
VL nucleus of thalamus and project to motor cortex
106
Function of Globose and emboliform nuclei pathways to both the red nucleus and through the thalamus to the motor cortex are involved in
Fine motor control of the upper extremity.
107
Damage to Globose and emboliform nuclei pathways produces a
3-5 Hz Intention tremor during reaching tasks. No similar effect of damage on gait or standing balance
108
Neuroanatomical areas controlling grasping
Visomotor transformations -mediated by the PPC and premotor cortex
109
Damage to the PPC and premotor cortex causes
Impaired preshaping of the hand during goal-directed grasping
110
Key elements to reach, grasp & manipulation tasks are:
Locating the target - also called visual regard Coordination of eye and hand motions Reaching • Translocation of arm & hand in space • Postural support Grasping including grip & release In hand manipulation of object
111
There are 3 distinct conditions in target location- CEL
Control of eye & head movement Eye movement alone Locate in far periphery, eye, head & trunk movement together
112
Anticipation of the requirements of the task
Feedforward control
113
Feedforward Control is necessary for
the anticipation of events & resultant actions based upon previous experiences. In a new task, Visual information updates previous experiences.
114
When pointing to an object the arm and hand is controlled as
One unit
115
When reaching to grasp the hand is controlled
independently of rest of arm
116
Reaching alone as in pointing and reaching for grasp are
Two separate processes controlled by different sets of neurons
117
Velocity profiles are different depending upon task
Point & touch versus Grasp
118
Types of reaching tasks done in rehab
* Reach & point
* Reach & grasp
* Reach, grasp & throw
* Reach, grasp & manipulate
* Reach, grasp & place in box or remove from box
119
Part of the brain that cognates and recognizes sizes
Ventral visual stream -cognitive recognition of the relative size of objects; A pathway to the temporal lobe.
120
Ebbinghaus illusion
The disk surrounded by smaller circles appears larger than a disk surrounded by large circles.
121
Grip size is controlled through the
Dorsal visual stream to the posterior parietal cortex
122
Size recognition is controlled by the
Ventral visual stream to the temporal lobe
123
Visual feedback has an important kinematic effect on
Reaching.
124
T / F- Reaching with visual feedback longer duration but greater accuracy than without visual feedback
T
125
Cortically blind but visual behaviors- significant correlation between pointing and target position mediated by superior colliculus Role in grasp studies- No difference in the kinematics of the grasp component with or without visual feedback. However when vision is used to enhance grasp accuracy, the thumb position in relation to wrist is the key to visual feedback of grasp
T
