Cognition

Question 1

What is cognition?

Answer 1

• The faculty of knowing in both awareness and judgement

Question 2

What is cognitive function?

Answer 2

The set of processes that allow humans and animals to perceive external stimuli, extract key information, hold it in memory and ultimately generate thoughts and actions that help it reach desired goals.
- Cognition is conscious and unconscious
- Can occur without conscious experience because they :
- occur too quickly
- Occur automatically in the background of current processing (transforming experiences into memories)

Question 3

What are the major areas of cognition?

Answer 3

• Executive function (management of cognitive processing)
• Attention and concentration
• Perception
• Emotion
• Language
• Memory
• Control of motor behaviour

Question 4

Where is cognition thought to reside?

Answer 4

• In the cerebral cortex
• 10-20 billion neurones in the c cortex
• Over half of brain tissue
• Folfing gives approx 1.6 sq m
• As you ascenf the evolutionary tree the size of the cerebral cortex increases
• Size gives an impression of importance

Question 5

How can environment effect the developmemt of the brain?

Answer 5

• Neglect in early childhood can alter brain development

Question 6

Why is it thought that hiigher mental function resides in the cerebral cortex?

Answer 6

• Cognitive abilities closely parallel it’s expansion in structural complexity
• Patients who have damage to their cerebrum have clear cognitive deficits
• No convincing evidence that cognition resides outside of the brain

However, when it comes to cognition we know relatively little about the ‘how’ and much more about the ‘where’

Question 7

What are some tehcniques used to study brain function?

Answer 7

Techniques used to study brain function
* Single unit recordings
* Multi unit recordings
* Pharmacological interventions eg Wada
- In vitro recordings - brain slices. Single or multi-unit recordings
Technique
* CAT or CT- computer assisted tomography
* MRI and fMRl- magnetic resonance imaging
* PET- positron emission tomography
* MEG- magnetoencephalography
* EEG- electroencephalography
* Optical Topography

Question 8

What is in vivo microelectrode recording in experimental animals?

Answer 8

-Can record from neurones during a cognitive task
Pros:
- Excellent temporal resolution
- Can identify individual neurones responding/ directing a behavioural output

Cons :
- Restricted to small number of neuroens- not the whole network
- Invasive
- Not usually done in human

Question 9

What is Magnestic resonance imaging- MRI ?

Answer 9

Non invasive

MRI
Magnetic coils that produce a static magnetic
field in the long axis of the patient

Magnetic coils that produce a static field
perpendicular to the long axis A radiofrequency coil specifically designed for
the head or other body part (not shown) perturbs the static fields to generate
an MRI .
Imaging produces very crisp and detailed anatomical images

Question 10

What is a functional MRI- fMRI?

Answer 10

Non invasive
Functional MRI- fMRl
Blood oxygenation level dependent signal- BOLD
Good spatial and
temporal resolution
Oxygenated and deoxygenated blood have different magnetic resonance
Active brain areas use more oxygen than inactive areas and require more blood flow
fMRl examines the change in magnetic resonance brought about by changes in blood oxygenation
21
Difference in signal provides a measure of neuronal activity

Question 11

What is transcranial magnetic stimulation?

Answer 11

• Non invasive
• Magnetic field generate over the scalo
• Induces change in electrical field in underlying brain tissue
• Transiently interrupts local processing
• Creates a reversible brain lesion

Question 12

What is left and right parietal lobe damage?

Answer 12

Left Parietal Damage
* Impaired verbal short term
memory (can only repeat back 2-
3 letter at a time)
* Agraphia (inability to
communicate through writing)
* Dyscalculia (difficulty in
performing calculations)

Right Parietal Damage
* Constructional apraxia (inability to
copy drawings or manipulate objects to form patterns or designs)
* Disengagement — cannot shift
attention from one stimulus to
another
* Impaired visual short term memory
* Anosognosia (a deficit of self-
awareness — patients are unaware
of the existence of their disability)

Question 13

Explain parietal lobe and attention

Answer 13

• Left lobe = attends to right hemispace
• Right parietal lobe attends to both left ad right hemispace
• Left hemisphere lesion = neglect not as severe
• Righr hemisphere lesion = left neglect

Question 14

What is contralateral neglect syndrome?

Answer 14

British neurologist W.R Brain described 3 patients with parietal lobe lesions:
…always making the same error of choosing a right
turning instead of a left, or a door on the right instead of
one on the left. In each case there was a massive lesion
in the right parieto-occipital region…
* An inability to perceive and attend to objects, or even
one’s own body, in a part of space, despite the fact
that visual acuity, somatic sensation, and motor ability
remain intact
* Affected individuals fail to report, respond to, or even
orient to stimuli presented to the side of the body (or
visual space) opposite the lesion

Question 15

What is left temporal damage?

Answer 15

• Problems with speech and language processing and comprehension of verbal material
• Problems with long term verbal memory and with sequential memory - can recall the gist without the detail
• Over-emotional, hypochondriacal, depressed
• Egocentric, paranoid, aggressive

Question 16

What is right temporal damage?

Answer 16

• Selective attention of verbal and visual inputs disturbed
• Loss of awareness of body language, facial expression, vocal itonation
• Indifference, inappropriate humour, fatuous (foolish behaviour), incongruent emotional reactions, impulsivity
• Impaired long term memory for pictures, faces, places

Question 17

What is prospagnosia?

Answer 17

• Face blindness

Question 18

What are the pre-frontal areas of the brain?

Answer 18

• Dorsolateral prefrontal — involved in
  reasoning, problem solving, sequencing
  and maintenance of behaviours, insight,
  judgment, temporal memory, emotional
  expression, language
• Orbitofrontal —Behavioural inhibition and
  emotional regulation, olfaction, empathy,
  evaluation of reinforcers/rewards,
  declarative memory.
• Mesial frontal (anterior cingulate)
  Attention, behavioural inhibition, initiation and motivation, motor function, social cognition (including theory of mind), explicit memory , insight anf judgment, language

Question 19

What is frontal lobe dementia?

Answer 19

Symptoms :
- Lose empathy
- lose inhibitions
- Become aggressive
- Can be easily distracted
- Can display compulsive rituals

Question 19

What is right frontal damage?

Answer 19

• Pseudopsychopathy - immature childish behaviourm little tact or social judgement, inappropriate swearing and foul language, sexual disinhibition

Question 20

What is left frontal damage?

Answer 20

• Abulia — loss of divergent thinking, loss of behavioural spontaneity,
  cannot self-direct behaviour so only functions in a familiar environment (with prompts)
• Stimulus bound — seen as perseveration (repetition of a particular response), risk taking, rule breaking, impulsivity, inflexibility,
  disorganised behaviour
• Poor temporal memory (what has just happened) and recency
  memory (the order in which things happened)
• “Pseudo-depression” — apathy, indifference, lack of emotion, lack of initiative (patient will not complain of being unhappy)

Question 21

What is the insular cortex?

Answer 21

The 5th Lobe? — The Insular Cortex
* Located between the temporal and frontal lobes
deep within the lateral fissure
* Involved in psychic awareness of viscero-sensory
feelings, stomach/gastric sensations, emotional
aspect to sensory feelings, heart rate/blood
pressure perception, psychic evaluation of
temperature and body states
* Self-awareness and social emotional processing

Question 22

How is language processed?

Answer 22

Processing of Language is complex
Context:
Visual context McGurk effect
Bank -
more than one meaning same sound and
spelling
Kernel/colonel -
same sound stimulus different meaning
and spelling
Tonal context

Question 23

What is wada procedure?

Answer 23

• Anaesthetize one hemisphere
• Typically done prior to ablative surgery for epilepsy - to determine which side of the brain is responsivle for vital cognitive functions spec, speech and language
• May consider a fMRI prior to surgery if important areas seen to be in surgical area

Question 24

What are association areas of the association cortex?

Answer 24

• AAs: Multiple inputs and outputs and are concened with interpretation of sensory experiences, discrimination and behaviour
• Anterior temporal AA : storage of previous sensory experiences. Stimulation may cause individual to recall objects seen or music heard in the past
• Posterior parietal AA : Visual info from occipital cortex and somatosensory info from parietal cortex is integrated into concepts of sizem form and texture = stereogenesis. An appreciation of body image also assembled here ( a body scheme that can be appreciated consciously - so that we know at all times where our body parts are located in relation to the environment. Critical for producing appropriate body movements
• Prefrontal AA: integration centre for multiple somatosensory inputs. Has links with all other sensory areas, lmbic system and thalamus. Top down executive processing of sensory and motor information.