Title: BV4 / Modul 3

Q: Which of the following components are not part of the stretch reflex?
A: Gamma-motor neuron

Q: Which neurotransmitters are used in the stretch reflex?
A: glutamate in the first synapse and acetylcholine in the second

Q: What is the primary role of the stretch reflex in motor control?
A: To maintain muscle length during changes in load

Q: What is the best description of signals from the Golgi tendon organ?
A: The Golgi tendon organ signals help to fine-tune muscle contraction

Q: When your foot is hurt by a sharp object the leg of the stimulated foot is withdrawn from the object. How can this response best be explained?
A: An innate neuronal network is activated by nociceptive afferents

Q: In which region of the CNS is the basic activity underlying alternating flexion and extension in the legs generated?
A: In the spinal cord

Q: How is the CPG for locomotion activated - which regions are most directly involved?
A: The reticular formation and mesencephalon

Q: During which of the following situations does the corticospinal pathway take control of the spinal locomotor CPG?
A: When you lift your leg over an obstacle during walking

Q: How would you best describe the indirect basal ganglia pathway?
A: Cerebral cortex – striatum – globus pallidus externa – subthalamic nucleus – globus pallidus interna – thalamus VA/VL – frontal cortex

Q: Which neurotransmitter and which effect does input from substantia nigra pars compacta exert on medium spiny neurons of the direct pathway?
A: Dopamine acting on excitatory D1 receptors

Q: Which firing pattern does globus pallidus neurons exhibit during a movement?
A: Transiently inhibited

Q: Which basal ganglia circuit is used to initiate saccadic eye movements?
A: Frontal cortex – striatum – substantia nigra pars reticulata– superior colliculus

Q: Which of the following functions are not linked to the basal ganglia?
A: Production of efference copies

Q: Which parts of the CNS send strong projections to the striatum?
A: Premotor cortex and primary somatosensory cortex (?)

Q: Which group of neurons typically undergoes degeneration in Parkinson´s disease?
A: Nigrostriatal dopamine neurons

Q: Which cortical area does not provide fibers to the corticospinal tract?
A: Primary visual cortex

Q: Which cortical area controls coordination between your hands?
A: Supplementary motor area

Q: Which cortical area controls movements performed under visual guidance?
A: Dorsal premotor cortex

Q: What is the best description of the role of vestibulocerebellum in motor control?
A: Control eye movements and integrate balance signals

Q: Which type of movement would most likely be impaired following a lesion of the rostral part of spinocerebellum?
A: Leg movements

Q: Which cell type is not located in cortex cerebelli?
A.
Golgi cells
B.
Basket cells
C.
Purkinje cells
D.
Stellate cells
E.
Giant cells of Betz
A: Giant cells of Betz

Q: Which of the following nuclei provides direct input to the cerebellar cortex?
A: Inferior olivary nucleus

Q: Which type of synaptic plasticity is likely to underlie motor learning?
A: LTD in parallel fiber input to Purkinje cells

Q: The ANS is under control from multiple parts of the nervous system. Which of the following regions/structures do you think provides the best description of an integral regulatory center of the ANS.
A.
Cerebral cortex
B.
Thalamus
C.
Hypothalamus
D.
Amygdala
E.
Hippocampus
A: Hypothalamus

Q: Which are the origins of the sympathetic nerves?
A: Spinal segments Th1 – L3

Q: Which of the following nuclei does not contain preganglionic parasympathetic neurons?
A.
Edinger-Wesphal nucleus
B.
Nucleus ruber
C.
The superior salivatory nucleus
D.
Nucleus ambiguus
E.
The dorsal motor nucleus of the vagus nerve
A: Nucleus ruber

Q: Which neurotransmitters and receptors are most commonly used by the sympathetic nervous system?
A: Preganglionic acetylcholine acting at nicotinic receptors, postganglionic noradrenaline acting at alfa and beta receptors

Q: How would you best describe the pathway mediating the response to a raise in blood pressure?
A: Baroreceptors – vagus nerve – nucleus of the solitary tract – nucleus ambiguus – vagus nerve – heart

Q: Which of the following statements give the most adequate description of the enteric nervous system?
A.
The enteric nervous system contains fewer neurons than the spinal cord
B.
Sympathetic activity stimulates peristalsis
C.Peristalsis can occur without sympathetic and parasympathetic activity
D.
Meissner´s plexus controls the gut musculature
E.
Auerbach´s plexus controls the glandular secretion in the gut
A: Peristalsis can occur without sympathetic and parasympathetic activity

Q: Vad heter den markerade strukturen?
A: Nucleus dentatus

Q: Var kommer majoriteten av axonen i den markerade banan sluta?
A: Basis pontis

Nucleus caudatus (ligger alltid invid laterala ventrikeln)

Nucleus caudatus

Pedunculus cerebellaris superior

Q: 1. Which combination of drugs can be used in the pharmacological treatment for Parkinson's disease:
A.
Dopamine agonist combined with peripheral dopamine antagonist
B.
Peripheral dopamine agonist with central dopamine antagonist
C.
Tyrosine with peripheral tyrosine antagonist
D.
Dopamine with peripheral dopamine antagonist
E.
L-dopa in combination with COMT-inhibitor
A: Dopamine agonist combined with peripheral dopamine antagonist

Q: What enzyme inhibitors are used in Parkinson's disease treatment?
A: COMT-inhibitors

Q: What can be said about the topographic structure of the M1?
A: In the M1 we have kinda a homonculus

Q: Which tracts are the areas in the M1 represented by (homonculus)?
A: - One area is represented by the corticospinal tract (upper motor neurons of it)
- Another area represents the face area respresented by the corticobulbar tract

Q: Which upper motor neurons can be found in the area in the M1 that represents the corticospinal tract?
A: Here u have upper motor neurons innervating the local circuits in the spinal cords that innervate muscles in the trunk, the upper and lower extremities

Q: Which upper motor neurons can be found in the area in the M1 that represents the corticobulbar tract?
A: The uppermotor neurons innervating the local circuits in the medulla that then should control the muscles of the face in this region

Q: What can be deduced from the size of each area in the M1 that represents an area of the body?
A: Whats important to note is that the size of the cortical area represented by certain muscles have a functional meaning, the larger the size the more complex the motor activity/behaviour

Q: WHy is the area for upper extremity in the M1 so large?
A: The upper extremity is greatly dominated by controll of our hands

Q: WHy is the area for face in the M1 larger than that of the trunk?
A: The face area is larger in the trunk bc we have a lot of muscles in our face to control facial expression

Q: What can happen if u continuously trigger a single upper motor neuron?
A: If u continuously stimulate a single upper motor neuron u can trigger a coordinated movmenet, not only a twitching muscle, especially of the trunk and extremities

Q: What would happen if the upper motor neuorns on the contralateral side are stimulated for a prolonged period of time (in terms of upper extremities)?
A: What happens is that this monkey starts to move the arms and hands in a very particular way, as if the monkey is trying to take something at put it in it's mouth - this is a normal behaviour used by the monkies every day and can be triggered by stimulation of a single upper motor neuron
Its not only that the upper motor neurons control the muscle of the thumb but the whole arm and  upper extremities that if u stimulate it long enough u can simulate this type of coordinated movement

Q: WHat is another feature of upper motor neurons?
A: Directional tuning

Q: What is an experiment on directional tuning?
A: - In this experiment monkeys push a joystick in a direction in accordance with instructions on the screen
- It is very clear that the activity increase when the arm is moved between 90-120 degreees in one region, but it also decreases its activity in anticipation of movement between 45-315

Q: What can we see in individual neurons (directional tuning)?
A: We can see that the individual neurons have a directional tuning, ex. we can see that one neuron increased in activity in anticipation of movements between 45-225 degrees

Q: How can we create a population vector representing movement direction?
A: By combining responses from 100s of neurons in the recording session we can construct a population vector that represents the movement direction of encoded by simultaneus activity of the entire population of recorded units

Q: What can be said about the direction which different neurons fire?
A: Some neurons like to fire in one way while other like to fire in another way (when joystick is moved in another direction)

Q: What happens when we stimulate individual motor neurons during long periods of time?
A: If we stimulate individual motor neurons during long periods of time we can induce coordinated movements of trunk and extremities

Q: What have we encoded for neurons?
A: We have encoded movement directions that are endcoded in the firing of individual upper motor neurons

Q: What does the M1 participate in?
A: Participates in learning of a wide range of movements

Q: What is the learning of a wide range of motor tasks based on?
A: These are based on sensorimotor, sequential tasks etc.

Q: What is PMA?
A: Premotor area

Q: What are the PMA and SMA lacking?
A: No detailed motor map (homonculus)

Q: How do SMA and PMA influence motor behaviour?
A: Indirect influence of motor behaviour through reciprokal connections to the primary motor cortex

Q: How do the upper motor neurons of the SMA and PMA innervate lower motor neurons?
A: These upper motor neurons don't/weakly inervates lower motor neurons , instead they ahve an indirect influence of motor behaviour through reciprokal connections to the primary motor cortex

Q: What can be said about the connections of teh neurons of teh PMA and SMA with motor neurons?
A: Weak connections with motor neurons - higher current is required to evoke motor behaviour

Q: What is required to evoke motor behaviour from the PMA and SMA?
A: Higher current is required to evoke motor behaviour

Q: How is the spinal cord supplied with blood?
A: One anterior and two posterior spinal arteries from the vertebral artery (sometimes PICA) and around 10 radicular arteries

Q: Initially you cannot elicit any tendon reflexes in the legs (knee-jerk or ankle-jerk stretch reflexes). What is the best description of components that participate in this type of reflex?
A: Group Ia afferents and Ia inhibitory interneurons

Q: The components discussed in Q3 participate in the control of everyday motor functions. What would be a good description of a situation when the stretch reflex comes into action.
A: You are playing a course mate a prank. He is standing in the lunch queue in front of you and you are kneeing him from behind so that his leg flexes abruptly in the knee joint.

Q: What would be a good description of a situation when the Golgi tendon organ system comes into action?
A: You are carefully lifting a precious porcelain bowl.

Q: När är golgi senorgan aktiv?
A: Golgi senorgan kommer igång bara man aktiverar muskeln lite grann

Q: Vad är en av de viktigaste orsakerna till att mna har stelnade reflexer?
A: Sprouting of afferents

Q: Finns det plasticitet i muskelspolar?
A: Nej, de är opåverkade

Q: After a 3-week period you find that Alberto´s tendon reflexes in the legs begin to reappear, likely due a reduction of swelling at the site of the lesion. However, the reflexes are not symmetric. Which of the following altertnatives is the most unlikely underlying cause?
A: The response to stretch differs between muscle spindles in affected and unaffected muscles

Q: It is now time to examine Alberto´s spinal cord by MRI. The examination shows that there is a large lesion at the affected level (indicated in Q1). Notably, however, part of the spinal cord has remained intact. The spared part is encircled in green in the figure below. WHich tracts is not within the circle?
A: Fasciculus gracilis

Q: Based on this information you need to inform Alberto about his prognosis. First, he wants to know whether he will ever be able to walk again. To give a proper answer you need to carefully consider what you know about the control of locomotion.
What would not be an appropriate description of the human locomotor system?
A: Training infants in walking make them learn to walk at an earlier age

Q: Recently, a technique was developed that enable patients with spinal cord lesions to recover a substantial ability to walk (published in 2018). It is based on patterned electrical stimulation of a specific structure in the nervous system. Based on your knowledge about the locomotor system, try to figure out which structure and explain why it was selected.
A: Lumbar dorsal roots

Q: Try to explain why the applied stimulation primarily affected relevant components within the stimulated structure (dorsal roots)(i.e. causing limited effects on components of which stimulation is not beneficial).
A: These components have a large diameter and are therefore primarily affected

Q: Regarding other functions than walking – for which of the following functions is it unlikely that he will maintain and/or regain some ability (ryggmärgsskada under umbilicus, förutom ventrala halvan av ryggmärgen)?
A: Extension of the big toes

Q: You first consider what you know about of the control of bladder function. Which of the following statements do you feel is most appropriate?
A
The sympathetic innervation of the bladder originates from S2-S4 and sympathetic activity causes the bladder to relax
B
Hypothalamus projects to the pontine micturition center which causes opening of the external sphincter
C
The periaqueductal gray receives input from bladder afferents and parasympathetic activity causes the bladder to relax
D
The pontine micturition center receives input from bladder afferents and sympathetic activity causes the internal sphincter to close
E
The parasympathetic innervation of the bladder originates from S2-S4 and hypothalamus projects to the midbrain periaqueductal grey
A: The parasympathetic innervation of the bladder originates from S2-S4 and hypothalamus projects to the midbrain periaqueductal grey

Q: At first you wish to rule out that Gustaf has a malignant prostate cancer so you send him for MR examination. It shows that there are no tumors, but clear signs of benign prostate hyperplasia. You discuss with the patient the possibilities to intervene surgically, but you both agree that it is best to start with a medication to see if that might help. Based on your knowledge of the autonomic control of the bladder, which type of drug would you primarily try and why?
A: An alpha 1 receptor antagonist

Q: From which spinal segments do the preganglionic neurons affected by this medication originate (alfa-1 receptor antagonist för kontroll av bladder function)?
A: Th10-L2

Q: After another eight months, Gustaf returns to you and tells you that he now has more or less the opposite problem. He finds it difficult to avoid urinating and he tells you that it often feels like the bladder is full without being so. You believe that he now suffers from an overactive bladder. Which medication would be most appropriate and why?
A: A muscarinic receptor antagonist

Q: Again, you need to inform Gustaf about possible side-effects. Several side-effects are indeed likely, but one is highly unlikely – which one (muscarin antagonist)?
A: Bradykardia

Q: Which is/are the effect(s) of the neurons degenerating in PD?
A: They inhibit medium spiny neurons in the indirect pathway

Q: Striatum is part of both the direct and indirect pathways of movement control. How would you describe the activity in the components of the direct pathway during initiation of a movement?
A: Transient activity in frontal cortex – transient activation of striatum – transient inhibition of globus pallidus – transient disinhibition of thalamus VA/VL – transient activation of motor cortex.

Q: Vilken aktivitet har globus pallidus i vila?
A: Tonisk

Q: You diagnose the patient according to your answer in Q1. You then need to inform the patient that he may experience other symptoms than those related to movement problems. Which combination is most likely?
A: Halluciantions and disturbed sleep

Q: Which medication do you prescribe to the  PD patient at first hand? Be prepared to explain your answer.
A: L-DOPA

Q: What is the primary effect of this medication (L-DOPA)?
A: It increases the levels of dopamine in striatum

Q: This medication (L-DOPA) can give side-effects, but one of those below are unlikely
A: Hypotonia - minskad muskelkontraktion

Q: The patient starts to take the medication  (L-DOPA) of Q7. When you see him again after 4 weeks he feels much better. His ability to move has improved markedly. You decide that you should meet the patient twice a year to monitor his condition.
Q9. Four years later the patient tells you that his condition has gradually worsened over the last few months. He has begun to feel increasing difficulties to perform movements despite of taking the medication decided in Q7. Which alternative medication would be possible in this situation?
A: Pramipexole - dopamin agonist

Q: What is the mechanism of action of this medication (dpoamine agonist)?
A: It is an agonist to D2 receptors

Q: Which combination of side-effects are likely to occur with this medication (dopamine agonist)?
A: hallucinations and nausea

Q: You are looking into the literature to find information about the placement of the electrode in patients who receive DBS. You find a description of the electrode trajectory as shown in the figure belo
A: Nucleus caudatus, thalamus (lateral)

Q: Which brain region is most commonly the target of DBS in Parkinson?
A: Nucleus subthalamicus

Q: Typiskt fynd för PD?
A: Occurrence of Lewy bodies (plack från dopaminproducerande celler) in mesencephalon (lägger sig där för det är där de skapas främst) and in cerebral cortex

Q: With regard to spinocerebellum – what is the best description of the role of this part in motor control?
A: Compare efference copy signals with proprioceptive feedback and send corrective signals

Q: Finally, from which artery is flocculus supplied with blood?
A: Anterior inferior cerebellar artery