Brain & Behavior - Week 1

Front 1

What does the CNS develop from?

What does the PNS develop from?

Back 1

The neural tube!

Both neural tube and neural crest cells!

Front 2

What is a dermatome?

What is a myotome?

Back 2

The area of skin innervated by a given spinal level.
The group of muscles controlled by a given spinal level

Front 3

Which segments supply the:
- head & neck
- upper limbs
- trunk
- lower limbs
- perineum

Back 3

head & neck: C2 -- 4
upper limbs: C5 -- T1
trunk: T2 - L1
lower limbs: L2 - S2
perineum: S2 downwards

Front 4

What is the function of each of the following special areas of the spinal cord?
1. C3-C5
2. T1 - L2,3
3. S2 - S4

Back 4

1. C3-C5: the phrenic nucleus
- (diaphragm) subject to decending control from b.stem. Has respiratory rhythmicity centre with cortical override
2. T1 - L2,3: sympathetic chain (preganglionic N's), subject to descending control from hypothalmic and brainstem nuclei
3. S2 - S4: origin of pudendal nerve, controls bowel and bladder emptying (descending cortical input = voluntary)

Front 5

At what level does the spinal cord end (what's the name of the structure)?

Back 5

The spinal cord ends in the connus medularis at L2, more caudal to this the nerves must descend before exiting the vertebral column.

Front 6

When you do a lumbar puncture what are you sampling?

Back 6

CSF from the expanded subarachnoid space known as the lumbar cisterna.

Front 7

What anchors the spinal cord to the coccyx? What anchors the cord laterally? What are both of these structures made of?

Back 7

The filum terminalis externa, an extension of layers from dural sac (dura & arachnoid), anchor the cord to the coccyx.
The Denticulate ligaments, extensions of the pia, anchor the cord laterally.

Front 8

What is grey matter made of? What do it's dorsal and ventral horns contain?
Between which segments would you find the lateral grey horns?

Back 8

Grey matter = cell bodies that form a continuous column, running the length of the spinal cord.
Dorsal horn = sensory nerves
Ventral horn = motor nerves
Lateral horns = (T1--L2), sympathetic preganglionic Ns

Front 9

Back 9

Front 10

What is the insula hiding under and what does it do?

Back 10

Hiding below the lateral fissure. Controls sound perception

Front 11

What are the 3 main functions of the limbic system?

Back 11

1. Olfaction (food and mates!)
2. survival
3. memory

Front 12

Back 12

Front 13

What 2 major things go through the thalamus?

Back 13

1. All sensory input, except olfaction! They relay through on their way to the cortex!
2. Information from basal nuclei and cerebellum modulating motor output also relay through the thalamus on the way to the cortex.

Front 14

Back 14

Front 15

What are the 3 sources of input for the hypothalamus?
What do the anterior and the posterior parts do?
What are 4 main functions of the Hothalamus?

Back 15

- Hormonal, neural and humoral (b/c BBB deficient in this area - Hothalamus is able to "see" what's in the blood).
Ant = Parasymp
Post = Symp
Functions: visceral component of emotion, body temp, drinking & eating.

Front 16

Back 16

Front 17

What are the 4 clinically recognizable levels of the nervous system?
What does each contain?

Back 17

1. Supratentorial - cerebral hemispheres and CN 1 & 2
2. Infratentorial - midbrain, pons, medulla, cerebrum and intracranial portions of CN 3 - 12
3. Spinal - spinal cord and intraveterbral portions of spinal nerves
4. Peripheral - all cranial, autonomic and spinal nerves outside the cranium and vertbral colums

Front 18

What is the difference between a segmental and a longitudinal function?

Back 18

segmental - axons (nerves) entering or leaving at a certain level, lesions here interrupt the flow of information to or from that part of the CNS (functions affected are those in that area of the CNS)
Longitudinal - axons (tracts) that are passing through a level on their way to influence something else. Lesions here will interrupt the flow of information to another area of the CNS

Front 19

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Front 20

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Front 21

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Front 22

Back 22

** Note that the size of dedicated cortical regions is proportional to the density of innervation of the body part and NOT its size.

Front 23

What characterizes lesions of the infratemporal level? Ie how are they presented/distributed?

Back 23

Lesions at the infratentorial level are characterized by sings on the SAME side of the head and on the OPPOSITE side of the body!

Front 24

What are the segmental and longitudinal functions of the spinal cord?

Back 24

segmental: sensory, motor & autonomic information for each spinal segment of the body

Longitudinal: ↓ motor & autonomic control of lower segments
↑ sensory information from lower segments

Front 25

What are the segmental and longitudinal characteristics of lesions at the spinal cord level:
- segmental
- longitudinal

Back 25

Segmental: signs at the level of the lesion
- loss of sensory input and autonomic output in a dermatome
- loss of motor output in a myotome
Longitudinal: destruction of the ↓&↑ pways = sensory and motor signs BELOW the level of the lesion

Front 26

There are no longitudinal functions or lesions possible at the peripheral level. That said, what are the segmental functions and lesions that occur at the peripheral level?

Back 26

Functions: Sensory, motor and autonomic information for the involved spinal segments only
Lesions: Ipsilateral sensory, motor & auto deficits for involved dermatomes & myotomes ONLY

Front 27

What are 2 similarities between the brainstem and spinal cord?

Back 27

- the grey matter is deep and the white matter is superficial
- the white matter consists of axons carrying sensory information rostrally, and motor information caudally

Front 28

What are 3 differences between the brainstem and spinal cord?

Back 28

grey matter in the spinal cord is continuous, whereas in the brainstem it is broken up into discontinuous series of functionally specialized nuclei.
Unlike the spinal cord, the brainstem:
- subserves "special senses" of hearing balance and taste
- contain as "reticular formation" responsible for the maintenance of vital functions and LOC

Front 29

What is contained within the 2 descending tracts (and what does each do/control):
- corticospinal tract
- corticobulbar tract

Back 29

Corticospinal:
axons carrying voluntary output from the cortex --> spinal cord, controlling the msks of the body
Corticobulbar:
- voluntary output from the cerebral cortex to the brainstem
- modulate and coordinate posture, tone & movement, as well as autonomic fxns

Front 30

What are the 2 main ascending white matter tracts in the brainstem?

Back 30

1. Spinal cord ---> Thalamus
eg. somatosensation from body surface on it's way to the cortex for perception

2. spinal cord ---> cerebellum
e.g. proprioceptive data for subconcious cerebellar processing

Front 31

On the dorsal side of the brainstem there are 3 peduncles, what does each one do?
What would you see if you cut these peduncles away?

Back 31

1. Superior peduncle - connects midbrain to cerebellum
2. Middle - connects the pons and cerebellum
3. Inferior - connects the medulla and cerebellum
** if the peduncles are cut one sees the floor of the 4th ventricle

Front 32

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Front 33

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Front 34

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Front 35

Identify which CN go with the following labeled nuclei

Back 35

Front 36

The brain can be thought of as being fed by 2 pairs of major arteries. What are these pairs and what do they supply (in general terms)?

Back 36

1. The vertebral arteries - they enter via the foramen magnum and join to form the basilar arter on the ventral aspect of the pons
2. The internal carotids - enter AT the foramen lacerum and bifurcate into the anterior cerebral and middle cerebral

Front 37

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Front 38

During an angiogram, contrast is injected into either the ICA or the VA. Which will each of these arteries fill?

Back 38

ICA - will fill the anterior and middle cerebral arteries and branches

VA - will fill the basilar artery, posterior cerebral artery (? and the AICA & PICA)

Front 39

What are watershed areas and what is their significance?

Back 39

Watershed areas - areas of neural tissue that lie at the border of vascular territories. They are supplied but 2 major blood vessels, BUT they are at the end of the line; so if the Bp falls (even a little) then they are the first to suffer.
perfusion = 30% then electrical activity falls
perfusion = 10% neurons will die

Front 40

Describe a subarachnoid hematoma (cause, symptom, tx)

Back 40

Usually caused by a rupture of an aneurysm in the circle of willis at the base of the skull.
The blood leaks into the CSF or can spray agains the brain tissue itself, causing the worst headache of your life.
Aneurysms can be repaired or clipped by accessing them through the carotid.

Front 41

Describe a subdural hematoma (cause, course, effects)

Back 41

Small vessels are broken so it's a slow bleed - the blood breaks down and becomes osmotically active drawing more fluid out --> more swelling --> more vessels get broken.
Usually d/t minimal trauma.
Effects can be minor as the brain will accommodate the slow squishing

Front 42

Which vessels cause an extra-dural hematoma? What usually causes this hemorrhage?

Back 42

Middle meningeal artery and vein.
Usually trauma - hemorrhage compresses the brain that will regain it's shape/function once blood evacuated

Front 43

What is an arteriovenous malformation?
What are the possible complications of them?

Back 43

It's when you have direct communication between arteries and veins without any intervening capillaries.
These tend to be dynamic and can change shape and cause compressive deficits. High risk of rupturing!