Questão 1
Questão
Three types of movements (antialphabetic):
- [blank_start]Voluntary[blank_end] movements
- [blank_start]Rhythmic[blank_end] movements
- [blank_start]Reflexes[blank_end]
Responda
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Voluntary
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Rhythmic
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Reflexes
Questão 2
Questão
The visuomotor delay is approximately [blank_start]200[blank_end] ms.
The proprioceptive delay is approximately [blank_start]50[blank_end] ms.
Responda
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200
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250
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300
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150
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50
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30
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80
-
150
Questão 3
Questão
Three things that make motor control difficult (alphabetic):
- [blank_start]environmental[blank_end] uncertainty
- [blank_start]motor[blank_end] noise
- [blank_start]sensory[blank_end] noise
Responda
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environmental
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motor
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sensory
Questão 4
Questão
The human body has "only" 600 muscles. Nonetheless motor control is very difficult, since the number of possible movement patterns increases [blank_start]exponentially[blank_end] with the [blank_start]degrees of freedom[blank_end].
Responda
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exponentially
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degrees of freedom
Questão 5
Questão
The principle of [blank_start]redundancy[blank_end] means that there is a [blank_start]gap[blank_end] between high- and low-level specification. Any high level task can be achieved in [blank_start]infinitely[blank_end] many low level ways.
Responda
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redundancy
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gap
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infinitely
Questão 6
Questão
[blank_start]Fitt's[blank_end] law describes the [blank_start]speed-accuracy[blank_end] trade-off.
Questão 7
Questão
In simple grasping tasks the paths of hand movements are usually [blank_start]straight[blank_end] and the speed profiles are [blank_start]bell-shaped[blank_end].
Questão 8
Questão
The two-thirds power law:
[blank_start]angular[blank_end] velocity ~ [blank_start]curvature[blank_end]^(2/3)
Questão 9
Questão
Three levels of analysis:
(1) [blank_start]Computational[blank_end]: What is the [blank_start]problem[blank_end] the brain is trying to solve?
(2) [blank_start]Algorithmic[blank_end]: What is the [blank_start]strategy[blank_end] to solve this problem?
(3) [blank_start]Neuronal[blank_end]: How is it done by the nervous system?
Responda
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Computational
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Algorithmic
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Neuronal
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problem
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strategy
Questão 10
Questão
The forward model [blank_start]predicts behaviour[blank_end] based on [blank_start]motor commands[blank_end].
The inverse model [blank_start]calculates motor commands[blank_end] from [blank_start]desired behaviour[blank_end].
Questão 11
Questão
Feedforward ([blank_start]open[blank_end]-loop) control:
Because of the delays in the sensorimotor system, open-loop control is used for [blank_start]short[blank_end] movements.
Disadvantages:
- [blank_start]Inaccuracies[blank_end] cannot be corrected
- [blank_start]Unexpected changes[blank_end] will not be taken into account
Responda
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short
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long
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open
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closed
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Inaccuracies
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Delays
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Noise
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Unexpected changes
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Inaccuracies
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Noise
Questão 12
Questão
In order for feedforward control to be sufficient, the [blank_start]inverse[blank_end] model would have to be perfect.
Questão 13
Questão
Feedback (closed-loop) control can compensate for errors due to
Questão 14
Questão
In an experiment, subjects are given 400g blocks and practice to lift them.
After training the weight is surprisingly increased to 800g.
The experiment shows the subjects use
Questão 15
Questão
The [blank_start]gain[blank_end] factor is the amount by which the [blank_start]corrective[blank_end] motor command is increased or decreased per unit of error.
Questão 16
Questão
[blank_start]High[blank_end] gain and [blank_start]high[blank_end] sensorimotor delay can lead to [blank_start]overcompensation[blank_end] and [blank_start]instabilities[blank_end].
Responda
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High
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Low
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high
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low
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overcompensation
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too little compensation
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instabilities
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a stable motor command
Questão 17
Questão
An [blank_start]efference[blank_end] copy is an internal copy of an outflowing ([blank_start]efferent[blank_end]), movement-producing signal generated by the motor system.
Responda
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efference
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afference
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efferent
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afferent
Questão 18
Questão
Two strategies to compensate for sensory delays:
(1) [blank_start]Intermittency[blank_end] of movements
(2) [blank_start]Prediction[blank_end]
Questão 19
Questão
The experiment where you move your eyeball with your hand and the world moves shows that the brain uses [blank_start]motor commands to the eye[blank_end] in order to predict the eye's position.
Questão 20
Questão
What's the problem with using a forward model in feedback control to predict the position of a limb.
Responda
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Errors accumulate over time.
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Delay leads to instabilites.
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Actually an inverse model would have to be used.
Questão 21
Questão
Which are the main structures of the CNS involved in motor control?
Questão 22
Questão
A motor unit consists of [blank_start]a spinal motor neuron[blank_end] and [blank_start]the muscle fibres that it innervates.[blank_end]
Responda
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a spinal motor neuron
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a sensory interneuron
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a pyramidal motor neuron
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the muscle fibres that it innervates.
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the motor neurons it projects to.
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the disc in the spinal cord it projects
Questão 23
Questão
A muscle is typically innervated by [blank_start]a few hundred[blank_end] spinal motor neurons.
Responda
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a few hundred
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a few thousand
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about 50
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about 50.000
Questão 24
Questão
The [blank_start]innervation number[blank_end] tells how many muscle fibres a motor neuron innervates.
Questão 25
Questão
The innervation number
Responda
-
indicates the increment in force when the motor unit is activated.
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can be very different for the same muscle.
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is the same for all neurons that project to one muscle
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indicates the speed by which the muscle is activated
Questão 26
Questão
The muscle force is controlled by
Responda
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recruitment (how many motor neurons of the unit fire)
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the discharge rate of motor units
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the innervation number of the motor unit
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the axon diameter of the motor neuron
Questão 27
Questão
Motor units differ in [blank_start]speed[blank_end] and maximum [blank_start]force[blank_end].
Questão 28
Questão
Recruitment:
[blank_start]Small[blank_end] motor neurons are recruited first because of the [blank_start]high[blank_end] resistance within their axon.
They have a [blank_start]lower[blank_end] innervation number and therefore produce [blank_start]less[blank_end] force.
Responda
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Small
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Large
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high
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low
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lower
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higher
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less
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more
Questão 29
Questão
Spinal reflexes are [blank_start]involuntary[blank_end] and triggered by [blank_start]external stimuli[blank_end].
Despite classical theory they can be quite flexible.
Responda
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involuntary
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external stimuli
Questão 30
Questão
The withdrawal from a painful stimulus is called [blank_start]flexion-withdrawal[blank_end] reflex.
The [blank_start]flexor[blank_end] muscle is activated and the [blank_start]extensor[blank_end] muscle is inhibited.
This is called [blank_start]reciprocal innervation[blank_end].
The opposite effect happens on the [blank_start]contralateral[blank_end] limb.
The force [blank_start]does[blank_end] (does or does not) depend on the stimulus intensity.
Responda
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flexion-withdrawal
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flexor
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extensor
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reciprocal innervation
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contralateral
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does
Questão 31
Questão
The stretch reflex is a [blank_start]muscle contraction[blank_end] in response to stretching within the muscle.
The antagonist muscle is inhibited, this is called [blank_start]reciprocal innervation[blank_end].
The stretch reflex increases the [blank_start]stiffness[blank_end] of the muscle.
Responda
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stiffness
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muscle contraction
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reciprocal innervation
Questão 32
Questão
The areas of the cerebral cortex that are used in motor control:
- [blank_start]Primary motor cortex[blank_end] (M1)
- [blank_start]Premotor cortex[blank_end] (PM)
- [blank_start]Supplementary motor area[blank_end] (SMA)
Responda
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Primary motor cortex
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Premotor cortex
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Supplementary motor area
Questão 33
Questão
The motor cortices receive input from
Questão 34
Questão
The motor homunculus is most detailed for the [blank_start]primary motor cortex[blank_end].
It disappears if you [blank_start]zoom on[blank_end].
Responda
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primary motor cortex
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premotor cortex
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supplementary motor area
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zoom in
-
zoom out
Questão 35
Questão
The motor pathway to lateral motorneurons runs [blank_start]contralateral[blank_end] and controls mainly [blank_start]distal muscles[blank_end].
It includes the [blank_start]corticospinal tract[blank_end].
The patway to medial motorneurons runs [blank_start]ipsilateral[blank_end] and controls mainly [blank_start]stance and posture[blank_end].
Responda
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contralateral
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ipsilateral
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distal muscles
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nearby muscles
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corticospinal tract
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medial tract
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ipsilateral
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contralateral
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stance and posture
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fine movements
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unconscious movements
Questão 36
Questão
The corticospinal tract
The connections come from the cortical layer [blank_start]V[blank_end].
Many of these connections terminate on spinal [blank_start]interneurons[blank_end].
Only [blank_start]M1[blank_end] contains neurons projecting directly to spinal motor neurons. These cortical neurons are called [blank_start]corticomotorneurons[blank_end]. Those neurons have only one synapse.
Responda
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V
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IV
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III
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II
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I
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interneurons
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medial neurons
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projection neurons
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M1
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PM
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SMA
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corticomotorneurons
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complex neurons
Questão 37
Questão
The axons of corticomotorneurons terminate on [blank_start]spinal motor neurons[blank_end].
The can also influence other muscles via spinal [blank_start]interneurons[blank_end].
Most of the time the excite agonist muscles and inhibit antagonist ones.
Responda
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spinal motor neurons
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the muscle fiber
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interneurons
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projection neurons
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receptors
Questão 38
Questão
Reading information about the direction of a movement from several motor neurons is done via [blank_start]population codes[blank_end].
Questão 39
Questão
Neuronal tuning with respect to movement means
Responda
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that firing rates of cortical motor neurons correlate with parameters of movement, e.g. direction, velocity, acceleration, ...
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that reinforcement learning can be applied to fine-tune execution of motor tasks.
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that firing rates of cortical motor neurons are highly intercorrelated ("tuning each other")
Questão 40
Questão
Different digits of the hand are controlled by sharply separated areas in M1.
Questão 41
Questão
Four symptoms of cerebellar disorders:
[blank_start]Hypotonia[blank_end]: A diminished resistance to passive limb displacements.
[blank_start]Astasia-abasia[blank_end]: An inability to stand or walk.
[blank_start]Ataxia[blank_end]: The abnormal execution of multijointed voluntary movements, characterized by lack of coordination.
[blank_start]Action tremor[blank_end]: A form of tremor at the end of a movement, when the patient attempts to stop the movement by using antagonist muscles.
Responda
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Hypotonia
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Astasia-abasia
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Ataxia
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Action tremor
Questão 42
Questão
The basal ganglia are involved in
Questão 43
Questão
Relation between function and areas of the brain (hypothesis)
Responda
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basal ganglia
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motor cortex
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parietal cortex
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cerebellum
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thalamus
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prefrontal cortex
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medulla oblongata
Questão 44
Questão
The motor control loop
Responda
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controller
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state estimation
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efference copy
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sensory feedback
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forward model
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inverse model
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gain
Questão 45
Responda
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Comparator
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Sensed state
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Input processing
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Sensor
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Forward model
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Inverse model
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Estimated state
Questão 46
Responda
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dynamic
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predictive
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sensory
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correction
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estimation
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gain
Questão 47
Responda
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Desired state
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Estimated state
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Feedforward controller
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Inverse controller
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Motor command
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State estimation
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Actuator
Questão 48
Questão
Optimal feedback control
Responda
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position
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weight
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motor command
Questão 49
Questão 50
Questão
The forward-model is used at the [blank_start]beginning[blank_end] of movements.
Questão 51
Questão
There are slow- and fast-[blank_start]twitch[blank_end] muscle fibers.
Questão 52
Questão
[blank_start]Supraspinal[blank_end] centers play an important role in modulating and adapting spinal reflexes, even to the extent of reversing movements when appropriate.
Questão 53
Questão
Stretch reflex:
In addition to the muscle that is stretched [blank_start]synergistic[blank_end] muscles are contracted.
Questão 54
Questão
M1: Brodman [blank_start]4[blank_end]
PM & SMA: Brodman [blank_start]6[blank_end]
Questão 55