Neuro- week 3

Question 1

describe attention

Answer 1

part of executive function

reflective of frontal lobe function, especially prefrontal cortex

dysfunction is the main sign in delirium

Question 2

types of attention

Answer 2

focused - respond discretely to specific stimuli

sustained - maintain attention during sustained or repetitive activity

selective - attention in the face of distracting stimuli

alternating - switch between tasks which have different cognitive requirements

divided - may not exist and just be people very good at alternating seamlessly

Question 3

what does damage to the hippocampus cause

Answer 3

inability to form declaritive memories
anterograde amnesia
this is because the hipocampus is important in encoding short term memories into long term

Question 4

what are the five stages of completing goals

Answer 4

1 - a best guess at what reality is
2- a commitment to some goal
3- hypothesis generation on how to achieve the goal
4- action in the world
5- dynamic monitoring on whether the goal is getting closer or further away

Question 5

what are the parts to having a best guess at what reality is

Answer 5

self vs other - separating ourselves from the environment

agent vs object - things capable of action vs inanimate objects

agent intentionality - thinking about what something else might be planning
i. Mirror neurons which mirror what others are doing to get insight into their intentions

Question 6

where do bottom up goals come from

Answer 6

limbic system

goals essential to survival such as reproduction

Question 7

where do top down goals come from

Answer 7

prefrontal cortex

higher functions determining complex, non-essential goals

Question 8

how do we monitor if a goal gets closer or further away after an action

Answer 8

in absense of knowledge, all actions are equal

dopamine in mesolimbic and mesocortical pathways have a role in reward and prefrontal cortex processing

Question 9

where are language centres in the human brain

Answer 9

85% on the left
10% on the right
5% split

Question 10

what does damage to broca’s area lead to?

Answer 10

difficulty expressing language

Question 11

what does damage to wernicke’s area lead to?

Answer 11

difficulty understanding language

speech becomes jumbled and difficult to understand because they don’t understand what they are saying

Question 12

what connects broca’s area and wernicke’s area?

Answer 12

the arcuate fasciculus

Question 13

what does damage to the arcuate fasciculus lead to?

Answer 13

innability to repeat things said to you

Question 14

describe fluent language problems

Answer 14

able to speak a lot.

damage to wernicke’s

Question 15

describe non-fluent language problems

Answer 15

broca’s or arcute fasciculus damage

Question 16

what is the definition of stroke

Answer 16

rapidly developing clinical signs of focal (or global) disturbance of cerebral function, lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin

Question 17

what is the definition of TIA

Answer 17

brief episodes of neurologic dysfunction caused by focal brain or retinal ischemia, with clinical symptoms typically lasting less than one hour, and without evidence of acute infarction

Question 18

what does the left carotid come off of

Answer 18

aortic arch

Question 19

what does the right carotid come off of

Answer 19

the brachiocephalic trunk

Question 20

what do the vertebral arteries come off of

Answer 20

the subclavian arteries

Question 21

where do the vertebral arteries travel?

Answer 21

in the transverse processes of the spine

Question 22

what do the vertebral arteries join to become

Answer 22

the basilar artery

Question 23

what does the basiar artery split into?

Answer 23

the right and left posterior cerebral arteries

Question 24

what is the definition of infarction

Answer 24

morphological entity; a large, localised area of tissue necrosis brought about by reduced blood flow

Question 25

what is the definition of ischaemia?

Answer 25

perfusion below the metabolic needs of the tissue

Question 26

what subcategories of stroke are there and what are the proportions of each one

Answer 26

5% subarachnoid haemorrhage 15% intracerebral haemorrhage 80% ischaemic stroke.

Question 27

what subcategories of ISCHAEMIC stroke are there and what are the proportions of each one

Answer 27

* 50% artherothromboembolism * 25% small artery disease * 20% cardiac source of embolism * 5% rare causes

Question 28

what kinds of infarct are there

Answer 28

* Occlusion of a vessel; infarction * Hypoperfusion; watershed infarct * Cardiac arrest; selective vulnerability and global ischaemic injury

Question 29

what can cause strokes

Answer 29

``` – Atherosclerotic plaques – Arterial dissection – Emboli • Atherosclerotic material • Cardiogenic • Fat emboli • Rare cause; neoplasms, air bubbles ```

Question 30

what does a small infarct in internal capsule cause

Answer 30

weakness of opposite side of body, no damage to cortical structures or other tracts. Low mortality but can be very disabling

Question 31

what are water shed infarcts

Answer 31

seen when the systemic blood pressure falls to such a level that cerebral blood flow cannot be maintained. Brain is most affected where there is overlap from anterior and posterior perfusion. After 20-30 minutes of global cerebral ischaemia, the brain is irreversibly damaged. This causes laminar necrosis – lines running through the grey matter.

Question 32

where are common places for intracerebral haemorrhage

Answer 32

basal ganglia, cerebellum and brain stem

Question 33

why is hypertension a risk factor for intracerebral haemorrhage

Answer 33

• Causes small vessel disease • lipohyalinosis - Degenerative process initiated by fibrinoid necrosis. • Arteriolosclerosis - Concentric hyaline wall thickening of small arteries and arterioles

Question 34

what can cause intracerebral haemorrhage

Answer 34

* Hypertension * Vascular malformation * Neoplasia * Trauma * Cerebral amyloid angiopathy * Iatrogenic, other blood dyscrasias

Question 35

whats the most common cause of lobar haematoma (one lobe)

Answer 35

cerebral amyloid angiopathy – amyloid accumulate in the blood vessels and predispose them to rupture.

Question 36

describe subarachnoid haemorrhage

Answer 36

Often due to a vascular malformation – aneurysms – shown as white ring in CT common sites of aneurysm include at the bifurcation of the middle cerebral artery and at the joining points of communicating arteries with either anterior cerebral, posterior cerebral or internal carotid arteries. Rarely an aneurysm will rupture into the brain parenchyma itself so diagnosis would be intracerebral haemorrhage instead of sub arachnoid.

Question 37

what are some causes of venous infarction

Answer 37

• Sagittal sinus thrombosis o Oral contraceptives o Dehydration o Meningitis • Cortical vein thrombosis o Meningitis

Question 38

what happens in persistent high BP

Answer 38

• Autoregulatory range reset at a higher level • Curve shifts to right • Unwise to rapidly lower high blood pressure to ‘normal’, • When BP falls below 90 mm Hg: – autoregulation fails – CBF drops ischaemic brain damage can occur

Question 39

what is in the lateral grey horn

Answer 39

preganglionic fibres of the sympathetic nervous system

Question 40

where does the sympathetic trunk receive fibres from

Answer 40

T1 - L2 | runs above and below this but only receives fibres from here

Question 41

what joins the ventral rami to the sympathetic chain

Answer 41

the white and grey rami communicantes

Question 42

what is the enteric system

Answer 42

Intrinsic collections of neurones within the wall of the digestive tract, and can function independently of the CNS or PNS

Question 43

what happens to sympathetic fibres coming from the spinal cord

Answer 43

some will synapse with second neurone in sympathetic chain. Some will run through sympathetic chain without synapsing to prevertebral ganglia. Prevertebral ganglia occur only in abdomen and pelvis They lie anterior to the vertebral column

Question 44

what are the main prevertebral ganglia

Answer 44

Coeliac superior mesenteric inferior mesenteric inferior hypogastric ganglia

Question 45

what do alpha 1 receptors do

Answer 45

in smooth muscle in arterioles causing vasocontriction

Question 46

what do alpha 2 receptors do

Answer 46

on coronary arteries causing vasodilation

Question 47

what do beta 1 receptors do

Answer 47

on cardiac muscle causing increased contractility

Question 48

what do beta 2 receptors do

Answer 48

found in sino-atrial node to increase heart rate, in some smooth muscle in arterioles (esp. skeletal muscle ) causing vasodilation and in smooth muscle of bronchi causing bronchodilation

Question 49

what are the parts of the parasympathetic division

Answer 49

cranial outflow o Comes from the brain o Innervates organs of the head, neck, thorax, and abdomen sacral outflow o Supplies remaining abdominal and pelvic organs

Question 50

in what nerves do preganglionic fibres run in the cranial outflow

Answer 50

* Oculomotor nerve (III) * Facial nerve (VII) * Glossopharyngeal nerve (IX) * Vagus nerve (X) * Cell bodies located in cranial nerve nuclei in the brain stem

Question 51

describe the outflow via the vagus nerve

Answer 51

Fibers innervate visceral organs of the thorax and abdomen • Stimulates - digestion, reduction in heart rate and blood pressure Preganglionic cell bodies • Located in dorsal motor nucleus in the medulla Ganglionic neurons • Confined within the walls of organs being innervated

Question 52

describe the sacral outflow

Answer 52

Emerges from S2-S4 Innervates organs of the pelvis and lower abdomen Preganglionic cell bodies Located in visceral motor region of spinal gray matter Form splanchnic nerves

Question 53

what is the pharmacology of the parasympathetic NS

Answer 53

Ach binding to nicotinic and muscarinic receptors

Question 54

describe the functions of ANS neurones

Answer 54

• Sympathetic and parasympathetic afferents very similar to somatic sensory pathways. • Mostly free nerve endings in viscera, axons passing to ganglion (dorsal root ganglion or cranial nerve sensory ganglion). 2nd order neuronal cell body found in dorsal grey matter of spinal cord. • Sensory innervation of viscera o Usually not consciously perceived (except hunger, fullness) o Visceral reflexes (coughing, vomiting, swallowing etc) • In pathological conditions may result in pain and nausea- referred pain

Question 55

compare somatic motor system and the ANS

Answer 55

Somatic motor system • One motor neuron extends from the CNS to skeletal muscle • Axons are well myelinated, conduct rapidly ``` Autonomic nervous system • Chain of two motor neurons o Preganglionic neuron o Postganglionic neuron • Conduction is slower due to thinly or unmyelinated axons ```

Question 56

what are the anatomical differences between sympathetic and parasympathetic

Answer 56

• Arise from different regions of the CNS o Sympathetic – also called the thoracolumbar division o Parasympathetic – also called the cranio- sacral division • Length of postganglionic fibres o Sympathetic – long o Parasympathetic – short • Branching of axons o Sympathetic - highly branched • Affects many organs o Parasympathetic – few branches

Question 57

what neurotransmitter is released by preganglionic axons

Answer 57

acetylcholine for cholinergic and nicotinic branches

Question 58

what neurotransmitter is released by post ganglionic axons

Answer 58

* Sympathetic – most release noradrenaline (adrenergic) | * Parasympathetic – release acetylcholine (muscarinic receptors)

Question 59

describe the adrenal medulla

Answer 59

Major organ of the sympathetic nervous system Secretes great quantities adrenaline (some NA) Stimulated to secrete by pre-ganglionic sympathetic fibers

Question 60

where is the central control of the ANS

Answer 60

Control by the brain stem and spinal cord • Reticular formation exerts most direct influence o Medulla oblongata o Periaqueductal gray matter Control by the hypothalamus and amygdala • Hypothalamus – the main integration center of the ANS • Amygdala – main limbic region for emotions Control by the cerebral cortex

Question 61

describe horner's syndrome

Answer 61

Miosis (small pupil) Ptosis (drooping eyelid) Loss of sweating same side of face Redness of conjunctiva May result from interruption of sympathetic fibres centrally (anywhere between hypothalamus and upper thoracic level of spinal cord) or peripherally (cervical sympathetic chain) Causes include: Carotid artery dissection, brainstem stroke, syringomyelia

Question 62

describe syncope

Answer 62

* Vasovagal syncope: simple faint, seen commonly in young people with no underlying illness * Sudden vasodilatation occurs often caused by strong emotion. * Peripheral resistance decreases in arterioles and blood pressure falls. Cardiac rate fails to increase. Vagal stimulation may then occur leading to further bradycardia and to perspiration, increased peristalsis, yawning, nausea, pallor and salivation

Question 63

describe orthostatic hypotension

Answer 63

* Like vasovagal syncope but brought on by getting up from reclined position or standing still for long period * Often person stands up and then has steady fall in blood pressure but without compensatory rise in HR. Mild staggering or falling may precede loss of consciousness

Question 64

describe bladder control problems

Answer 64

* Prime example of autonomic dysfunction. * Common symptom of Multiple sclerosis patients.(75% of MS patients) * Main symptoms are urgency, frequency and urge incontinence. * Main cause is overactivity of detrusor muscle. Involuntary bladder contraction gives rise to feeling of need to void immediately despite bladder volume being low.

Question 65

what are some tests for ANS dysfunction

Answer 65

* Pupil reactions * Postural blood pressure – abnormal fall when getting up * Variation of HR with deep breathing * Lacrimal function - tears

Question 66

describe schizophrenia

Answer 66

0.5% prevalence • Disorder of PFC function • Excess dopamine hypothesis • Treated with dopamine antagonists

Question 67

describe depression

Answer 67

``` 12-20% prevalence • Disorder of Limbic function (?) • Monoamine deficiency hypothesis • Treated with • Diet, exercise • Drugs: SSRI, SNRI, TCA, MAOI, ‘Atypical antidepressants’ • Psychotherapy • ECT (rarely) ```

Question 68

describe anxiety

Answer 68

``` prevalence – 33% • Disorder of Limbic function (?) • Central role of amygdala • Treated with • Psychotherapy can be very effective • Drugs: SSRI, SNRI, TCA, Others ```

Question 69

describe personality disorders

Answer 69

``` – prevalence 12% • A - odd/eccentric o Paranoid o Schizoid o Schizotypal • B – dramatic/emotional/erratic o Antisocial o Borderline o Histrionic o Narcissistic • C – anxious/fearful o Avoidant o Dependent o Obsessive-compulsive ```