CNS 3 (Oct 3) Flashcards
1
Q
The diencephalon is located on either side of what structure?
A
-third ventricle
2
Q
What are the parts of the diencephalon?
A
- thalamus: relay nucleus, responsible for putting highlight on different aspects of your brain functions (emotions/memory, motor, and sensory pathways), big cortical input so modulates pathways to overlying cortex
- hypothalamus: autonomic NS regulation (regulate HR, BP, gut motility, pupil size, respiratory rate), generates fear and rage (closely associated with sympathetic NS), appetite, temperature, thirst, sleep and circadian rhythms (pineal gland), endocrine control
- posterior pituitary: axons of neurons that come from hypothalamus, some “hormones” released here are really NT’s
- pineal gland: back of thalamus immediately above cerebellum, has a projection from the hypothalamus and retina to regulate sleep and circadian rhythms, releases melatonin (endocrine gland)
3
Q
Label the diagram. What overarching area does the diagram show and is it the right or left
A
- right diencephalon
1. Thalamus
2. Pineal gland
3. Hypothalamus
4. Posterior pituitary
5. Corpus callosum
6. Cerebellum
7. Midbrain - can see connection between two thalami
4
Q
Label the diagram
A
- Basal nuclei
- Caudate head
- Lentiform nucleus (putamen and globus pallidus)
- Caudate tail
- Thalamus (Diencephalon)
5
Q
What provides the most input to the thalamus?
A
- 5 times the cortical input than other areas from the cortex
- thalamus needs to know what environment you’re in to decide what to let through
- only relevant info gets filtered to overlying cortex (selective attention)
6
Q
What is the function of the anterior cingulate cortex?
A
- looks at all info flowing through cingulate gyrus then determines if it’s real or imagined
- cortical connections, reality check
- when this is damaged, schizophrenia
7
Q
What does posterior thalamus do?
A
- filters all sensory information
- pain, temperature, proprioception, touch, pressure, taste, vision, hearing come into posterior thalamus
- in context of environment that you’re in, frontal cortex will provide an input (based on memories, ethics, thought, emotions) to posterior thalamus that only lets certain things go through to overlying cortex
8
Q
What is thalamic syndrome?
A
- stroke may occlude thalamic arteries
- loss of sensation on contralateral side of body
- contralateral paralysis (damage to descending motor fibres nearby)
- burning pain develops weeks later
- imbalance in emotion
- stroke involving deep penetrating branches of middle cerebral artery (diencephalon and deep nuclei are supplied by posterior and middle cerebral arteries)
9
Q
What are the three regions of the brainstem?
A
- midbrain
- pons (immediately in front of cerebellum- relays info to cerebellum)
- medulla
10
Q
What can we observe looking at the midbrain?
A
- large columns of white matter tracts
- hold up brain
- cerebral peduncles (corticospinal motor tracts)
- columns that support cortex
- represent much of motor pathway coming from brain and downwards to innervate muscles through spinal cord
11
Q
What can we observe looking at the pons?
A
- large
- contains cell bodies that will project into cerebellum
- cerebellar peduncle extending from pons into cerebellum carrying info
12
Q
What can we observe in medulla?
A
- two upside down pyramids
- left and right pyramidal tract carrying motor information from cortex through cerebral peduncles through pons into medulla in pyramidal tracts (same axons have different names depending on where you are)
13
Q
What nerves come from the brainstem?
A
-cranial nerves
14
Q
What are the tectum?
A
- superior (vision reflex relay) and inferior colliculi (auditory reflex relay)
- below pineal gland
- all four of these are called the corpora quadrigemina
15
Q
A
-sensory tracts carry touch, proprioception, pressure then they have nuclei within medulla where they synapse before they get relayed to other locations
16
Q
A
17
Q
A
18
Q
Describe the location of cranial nerves in relation to the brainstem
A
- 4 above pons
- 4 in pons
- 4 below pons
19
Q
Cranial nerve 0
A
- terminal nerve
- smell
- sensory
20
Q
Cranial nerve 1
A
- olfactory nerve
- smell
- sensory
32
Q
Describe the image
A
- cross section of brainstem above pons (midbrain)
- mickey mouse ears: can see corticospinal tract and cerebral peduncles
- black neurons: substantia nigra
- eyes: red nucleus (huge blood supply)
- mouth: cerebral aqueduct
- reticular formation surrounds cerebral aqueduct (periaqueductal grey matter)
36
Q
Where is the reticular formation located?
A
- extends from diencephalon to spinal cord
- long system of neurons around cerebral aqueduct and 4th ventricle
38
Q
What inputs go into cerebellum?
A
- visual input from colliculus
- vestibular information being detected by neurons in inner ear
- need to know where muscles are (proprioception)
- lots of info goes into cerebellum (this info is not filtered by the thalamus so this means cerebellum knows more about environment than you do because your thalamus is protecting things from you)
- cerebellum sees everything not just important things
42
Q
What are the coloured areas?
A
- purple: vestibulocerebellum (balance and eye movements) vermis
- red: cerebrocerebellum (planned action, learned action)
- yellow: spinocerebellum (limb coordination, muscle tone)
- red and yellow are lateral lobes
45
Q
Describe motor movement pathway in appendicular skeleton
A
- contralateral cortex wants to make motor movement in coordinated way ( eg pointing at projector)
- info comes from motor cortex through internal capsule
- then goes through cerebral peduncles to the pons
- corticopontine tract: part of cerebral peduncles from cortex to pons
- synapse in pons then axons in pons cross over to opposite side
- goes into opposite cerebellum via middle cerebellar peduncle where it is sending idea that it would like to make coordinated motor movement
- dentate nucleus in lateral cerebellum makes plan based on inputs
- goes back through cerebellar peduncles into middle thalamus (also filtering info from basal ganglia), filtered, then back to motor cortex
- impulse sent down corticospinal tract to synapse in anterior horn of spinal cord (lower motor neuron)
46
Q
Describe motor movement pathway in axial skeleton
A
- proprioceptive information comes into right medial cerebellum (vermis) via dorsal spinocerebellar tracts
- synapses in fastigial nucleus in cerebellar vermis (right side)
1. crosses over in superior cerebellar peduncle and is filtered in left thalamus before 1 motor cortex that then goes down pyramidal tracts and crosses over to right side (pyramidal decussation-point at junction of medulla and spinal cord where motor fibres from medullary pyramids cross the midline)
2. goes down vestibulospinal tract ipsilaterally for automatic balance (left side)
1 and 2 happen simultaneously
48
Q
What is the Romberg test?
A
- cerebellum receives visual, vestibular, and proprioceptive input
- cerebellum does pretty good job at calculating motor movements based on 2 out of the 3 inputs
- how to diagnose if they have problems with cerebellum; if patient is blind, you will probably know that from them telling you. If they have problems with proprioception or vestibular input, blindfold them and if cerebellum can make a calculation based on two inputs and one of them is diseased (and you removed vision) you’re only left with 1 input so you should see an increase in sway
