Session 11 - Higher functions of the brain Flashcards Preview

Semester 5 - CNS > Session 11 - Higher functions of the brain > Flashcards

Flashcards in Session 11 - Higher functions of the brain Deck (62):
1

What are the cortical associations areas?

The association areas make up 70 – 80% of the surface of the cortex. These regions receive, integrate and analyse signals from multiple cortical and subcortical regions and their output produces the complex human behaviours which make up our individuality.

2

How do gyri and adjacent lobes of the cortex exchange information?

through short-range fibres called Arcuate Fibres.

3

Give four occiptofrontal connections

o Superior Longitudinal Fasciculus
o Arcuate Fasciculus (Wernicke’s  Broca’s area – see below)
o Uncinate Fasciculus
o Cingulum

4

How thin is the cortex?

The cortex is thin (2-4mm thick), but has lots of convolutions to increase surface area.

5

What are the six hitological areas of the cortex?

I. Cortical Association Areas
II. Cortical Association Areas
III. Cortical Association Areas
IV. Inputs
 Motor and sensory cortex
 Thalamus
 Brainstem
V. Outputs
VI. Outputs
 Hippocampus
 Basal Ganglia
 Cerebellum
 Thalamus

6

What occurs in the frontal lobe? (7)

Dominant hemisphere (normally the left)
o Higher intellect
o Personality
o Mood
o Social conduct
o Language
o Broca’s area
o Motor cortex (primary function)

7

What occurs in frontal lobe lesions (2)

o Personality and behavioural changes
o Inability to solve problems

8

What four things occur in parietal lobe (3 in dominant, 1 in non-dominant)

Dominant Hemisphere
o Language
o Calculation
o Primary somatosensory (auditory signals)
Non-Dominant Hemisphere
o Visiospatial function (Shapes and images)

9

What occurs in parietal lobe lesions?

o Attention deficits
o Contralateral Neglect Syndrome
 Right hemisphere damage
 Don’t notice things on the left hand side
 Hair not brushed on left hand side
 Don’t notice food on left side of plate
 When asked to draw a clock only draw 1-6 or cram all numbers into the right hand side

10

What occurs in the temporal lobe (3)

o Memory
o Language
o Contains Wernicke’s Area
o Primary Auditory

11

What occurs in temporal lobe lesions?

o Recognition deficits (Agnosias)
 E.g. Prosognosia – Failure to recognise faces

12

What is occipital lobe?

Primary visual

13

What occurs in occipital lobe lesions

Vision loss

14

What do global lesions cause?

Dementia

15

How is speech and language organised?

Input - Wernicke's Area
Output - Broca's Area

16

What three things occur in wernicke's area?

 Primary Auditory Cortex
 Primary Visual Cortex
 Interpretation of written and spoken words`

17

What two things occur in brocas area?

 Formulation of language components
 Sends information to motor cortex

18

Where is language lateralised?

Left hemisphere

19

What is Wernicke's aphasia? 3

o Disorder of comprehension
o Fluent, but unintelligible speech (Jargon aphasia)
o Loss of mathematical skills

20

What is Broca's Aphasia?3

o Poorly constructed sentences
o Dis-jointed speech
o Comprehension fine

21

What is the dominant hemisphere of most people?

o 95% Left Hemisphere

22

What does the dominant hemisphere do? 5

o Processes information in sequence
o Language
 Spoken/Heard
 Written/Read
 Gestured/Seen (Deaf person can lose ability to use sign language)
o Maths
o Logic
o Motor skills (Most people R. Handed)

23

What does non-dominant hemisphere do? 5

o Looks at the whole picture
o Emotion of language
o Music/Art
o Visiospatial
 Recognition of shapes
o Body awareness

24

What are the main connections between hemispheres?

o Corpus Callosum (Anterior Commissure)
 Lesion greats two separate conscious portions – the dominant side could elicit a response from written word without non-dominant knowing why

25

What are memories a consequence of?

Neuronal plasticity

26

Where is memory stored?

Throughout cortex in appropriate areas

27

What are two types of memory?

Procedural and declarative memory

28

What does declarative memory do?

 What’s your name/age?
 Where do you come from?

29

What is procedural memory?

Tying shoelaces
Riding a bike

30

Give two temporal categories of memory

Short Term Memory
o Seconds to minutes
o Working memory

Long Term Memory
o Up to a lifetime
o Consolidation of short term memory

31

What four factors mean a short term memory enters long term memory?

Emotion
Rehearsal
Association
Automatic memory

32

What receptors have a role in synaptic plasticity?

Glutamate receptors

33

Outline the process of long term potenitation

o Activation of NMDA receptors and mGluRs can lead to up regulation of AMPA
o Strong, high frequency stimulation can cause Long Term Potentiation (LTP)
 This is thought to be the basis of long time synapse strengthening and learning

34

What is long term depression?

Opposite of LTP, weakening of infrequently used synapses. E.g. what did you have for lunch a month ago?

35

How is memory formed (4 steps)

1. Information from senses, e.g. auditory, visual passes to cortical sensory areas
2. Information passes to Amygdala and Hippocampus
 Forms memories
 Does not store or find memories
 Destruction of Hippocampus cause Anterograde Amnesia – failure to form new memories
3. Thalamus, Hypothalamus, Basal forebrain
4. Pre-Frontal Cortex
 Finds formed memories

36

When does memory function peak?

Age 25

37

How many individuals over 85 have alzheimers?

50%

38

What is anterograde amnesia?

 Failure to form new memories

39

Give 6 causes of anterograde amnesia

 Vascular interruption
 Tumours
 Trauma
 Infections
 Vitamin B1 deficiency (Korsakoff’s syndrome – Chronic alcohol abuse)
 Destruction of the Hypothalamus

40

What is retrograde amnesia and what is a cause?

 Failure to retrieve old memories
 Alzheimer’s Disease

41

What causes transient global amnesia?

TIA

42

What two things can cortex be broken down into?

o The Behavioural Cortex (Anterior to Central Sulcus)
o The Sensory Cortex (Posterior to Central Sulcus)

43

Give six causes of damage between areas of the brain?

o Trauma
o Stroke
o Deprivation of metabolism substrates
o E.g. CO inhalation
o Neurotransmitter synthesis and release
o E.g. Parkinson’s Disease
o Degeneration of Neurones
o Congenital failures

44

Describe strokes effcting primary motor cortical strips (precentral gyri)

o Impairment is proportional to the size of lesion
o Impairments are directly related to the ischaemic parts of the motor homunculus

45

What does infarct of anterior cerebral artery cause?

Leg

46

What does infarct of middle cerebral artery cause in terms of paralysis

The rest of the body

47

What does a stroke affecting sensory cortical strips cause

o Lesions caused by ischaemia
o Impairment is proportional to size of lesion
o Impairments are directly related to the ischaemic parts of the sensory homunculus

48

What type of infarct damages sensory cortical strips?

MCA

49

Define dementia

Dementia is an acquired loss of cognitive ability sufficiently severe to interfere with daily function and quality of life.

50

Give three overarching causes of dementia

Direct neuronal damage
Age related brain tissue degeneration
Vascular damage to brain tissue

51

Outline the prevalence of dementia

o Prevalence is age specific
 1% of dementia cases below 60 years old
 30-50% of dementia cases by 85 years old

52

What is presenile dementia

<65 years

53

Give four causes of age related brain tissue degeneration

o Alzhiemer’s Disease
o Pick’s Disease
o Huntington’s
o Parkinson’s

54

Give four other causes of dementia

o Infection
 Creutzfeldt-Jakob Disease (CJD)
 HIV Infection
 Viral encephalitis
o Metabolic
 Hepatic, Thyroid or Parathyroid Disease
 Cushing’s Syndrome
o Nutritional
 Thiamine, B12 or Folate deficiency
o Tumour
 E.g. Subfrontal meningioma
o Chronic Inflammatory
 Vasculitis
 Multiple Sclerosis
o Trauma
 Head injury
o Hydrocephalus

55

What is cortical dementia?

o Global-type personality changes in suffers
o Complex disabilities

56

What is the extreme presentation of anterior cortical dementa?

o Frontal lobe / Premotor Cortex
o Behavioural changes, loss of inhibition, antisocial behaviour, irresponsibility
o Huntington’s Chorea
o Metabolic Disease

57

What is the extreme presentation of posterior cortiacal dementia?

o Parietal and Temporal lobes
o Disturbances of memory and language
o No marked changes in behaviour or personality
o Alzheimer’s Disease

58

What occurs in subcortical dementia?

o Slowness and forgetfulness
o Gross changes in movement
o Increase in muscle tone

59

Give three early features of dementia

 Loss of memory of recent events
 Global disruption of personality
 Gradual development of abnormal behaviour

60

Give three intermediate features of dementia

 Loss of intellect
 Mood changes, blunting of emotions
 Cognitive impairment with failure to learn

61

Give three late features of dementia

 Reduction in self-care
 Restless wandering
 Incontinence

62

What causes ventriculomegaly in dementia?

Cortical atrophy
CSF pressure normal