Methods Of Cognitive Neuroscience

Question 1

What is the difference between cognitive psychology and cognitive neuroscience?

Answer 1

1. CP tries to understand mental operations and mental representations are; CN tried to understand the underlying substrates and mechanisms of them.
2. CP rests on the assumption that it is possible to dissect the mental operations that are involved in behaviour. CN also rests on this assumption but explores this further to associate certain mental operations with activity in specific brain areas, etc.

Question 2

What is a mental representation?

Answer 2

Anything that ‘means’ something to an individual.

Question 3

How are mental processes and mental representations linked?

Answer 3

1. Your eyes process the incoming light (e.g. a tree); like a passive camera
2. Your visual system processes the information (i.e. a basic mental process takes place)
3. You see the tree (one form of mental representation
4. Seeing the tree triggers a mental process (e.g. ‘avoid’ if you’re walking towards it)

Question 4

What do participants do in the Posner’s letter-matching task?

Answer 4

The subject responds “same” when both letters are either both vowels or both consonants, and responds “different” when they are from different categories.

Question 5

What is chronometry?

Answer 5

A technique using time measures (reaction times) to infer the workings of the brain

Question 6

What did Posner find from his letter-matching task?

Answer 6

• Faster reaction times when visually same than visually different
• Argued that different latencies reflect the degree of processing required to do the letter-matching task
• Order of Activation: Stimulus identity representations -> Phonetic representations -> Categorizations

Question 7

Explain the Version 2 of Posner’s Letter-Matching Task

Answer 7

The same letter-matching task as previously, except that an interval, defined as the stimulus onset asynchrony, separates the presentation of the two letters.

Question 8

What do participants do in the Memory Comparison task?

Answer 8

The subject is shown a set of one, two, or four letters and is asked to memorize them. After a delay, a single probe letter appears, and the subject indicates whether that letter was a member of the memory set.

Question 9

What are the hypothesized stages in the mental processes during a memory comparison task?

Answer 9

Stage 1: Encode (target identification)
Stage 2: Compare (compare the mental representation of the target with representations of items in memory)
Stage 3: Decide (was the target part of the items held in memory?)
Stage 4: Respond (press one of two buttons)

Question 10

Explain the technique, Optogenetics

Answer 10

A technique where a vector gets injected into the brain and we use light to manipulate neuronal activity

Question 11

What does fMRI do?

Answer 11

fMRI measures changes in blood flow/volume that are induced by neuronal activity (mental activity).

Question 12

What are mental processes?

Answer 12

A cognitive operation that transforms mental representations

Question 13

How can mental processes and representations be studied?

Answer 13

• Posner’s Letter Matching Task
• Memory Comparison Task

Question 14

How can single cell activity in the brain be studied?

Answer 14

• Single cell recordings
• For humans, it is occasionally used in treating epilepsy of the medial temporal lobe (MTL)
• For animals, it is extensively used in a variety of visual and auditory tasks
• A micro-electrode is inserted into brain tissue, and recordings of action potentials can be made from nearby neurons
• The animal can then be presented with various sensory stimuli or trained to perform some task, and the effects on neural activity can be monitored

Question 15

What are the advantages to (studying single cell acitivity in the brain)?

Answer 15

• Good spatial resolution
• Good temporal resolution

Question 16

What are the disadvantages to (studying single cell activity in the brain)?

Answer 16

• Samples represent only a very small fraction of a functional neural system

Question 17

What insights into mental functions can neurology yield?

Answer 17

• Trauma
• Stroke, vascular disorders
• Tumors
• Neurodegenerative diseases
• Infectious disorders
• Functional neurosurgery

Question 18

What are the difficulties of using neurology patients?

Answer 18

• Complex nature of brain injuries and their impact on cognitive abilities
• Hard to isolate specific functions affected by the brain injury (bcs brain is massively interconnected and patients often exhibit widespread changes)
• Variability among patients with naturally occurring lesions, thus complicating interpretations
• Brain’s plasticity can lead to remarkable reorganisation following neurological damage

Question 19

What is the difference between single and double dissociations?

Answer 19

Single:
- Observing two dependent variables by manipulating one independent variable
- With the single dissociation, the patient group shows impairment on one task and not one the other

Double:
- Observing two dependent variables by manipulating two dependent variable
- With double dissociation, one patient group shows impairment on one task and a second patient group shows impairment on another task
- Stronger evidence for a selective impairment

Question 20

What is TMS?

Answer 20

• Transcranial Magnetic Stimulation
• It is a technique where you simply inject a strong magnetic pulse into the brain and that then alters the brain activity
• Low-level currents that result in action potentials under the anodes

Question 21

How has fMRI revolutionised cognitive psychology?

Answer 21

Revolutionized our understanding of how function is localised in the human brain

Question 22

What are the benefits and limits of prominent methods used in neuroscience?

Answer 22

fMRI:
- Allows you to measure activity from seconds to hours
- Poor spatial resolution -> You can map the brain and its areas, but not image neurons

Single Cell Recordings:
- Allows you to measure single neurons, from milliseconds to days and so forth

Question 23

What did Posner find from the Version 2 of his Letter Matching Task?

Answer 23

As the stimulus onset asynchrony (interval) is lengthened, the difference in the reaction time to the physical-identity and phonetic-identity conditions become smaller, suggesting a transformation of the representation into a more abstract code

Question 24

What were the findings from the memory comparison task?

Answer 24

• Reaction time increases with set size
• The target letter must be compared with the memory set sequentially rather than in parallel

Question 25

What are the experimental techniques primarily used cognitive neuroscience?

Answer 25

• Animal research
• Neurology
• Brain imaging

Question 26

4-5 examples of what can cause brain damage