Cognitive Neuroscience

Question 1

What is episodic memory?

Answer 1

Specific episodes in the past

Often autobiographical

Question 2

What is semantic memory?

Answer 2

Knowledge of facts about the world

Derives from episodic memory

Question 3

What is procedural memory?

Answer 3

How to do things e.g. drive a car

Question 4

What is priming?

Answer 4

Exposure to one stimulus influencing response to subsequent stimulus

Question 5

What is classical conditioning?

Answer 5

Pairing of stimuli

Question 6

What is non-associative learning?

Answer 6

Habituation, sensitisation

Question 7

Where is the hippocampus located?

Answer 7

Medial temporal lobe

Question 8

Where do the main inputs to the hippocampus come from?

Answer 8

Parahippocampal gyrus

Question 9

Where do the main outputs from the hippocampus go?

Answer 9

Via the fornix to mammillary bodies

Question 10

What is the cortico-hippocampal information flow?

Answer 10

Primary sensory cortices
Association cortices
Parahippocampal cortices
Entorhinal cortex
Hippocampal formation

Question 11

What is the name of the anatomical connection between the hippocampus and the cortex?

Answer 11

Parahippocampal cortex

Question 12

What symptoms did patient HM show post surgery? What does this imply about which memory types were effected?

Answer 12

1. Memory of past intact - long term memory intact
2. Can participate in conversation - short term memory intact
3. Can learn new skills normally - procedural memory intact
4. Could not form new memories - anterograde amnesia

Question 13

How can we manipulate the hippocampus in animals to test its role in behaviour?

Answer 13

Lesions

Pharmacological inactivation

Question 14

What does the Morris Water Maze test?

Answer 14

Spatial memory

Question 15

What happens when CA1 cells are infused with muscimol?

Answer 15

Blocks spatial memory retrieval

Question 16

Would blocking NMDA receptors block spatial memory?

Answer 16

Yes

Question 17

What is a place cell?

Answer 17

Hippocampal pyramidal cell that fires when in a specific location
Creates a cognitive map

Question 18

What is a grandmother cell?

Answer 18

A theoretical neuron which represents a single complex concept/object

Question 19

What natural behaviour in rats would you exploit if wanting to test recognition memory?

Answer 19

Novel object preferance

Question 20

How do we calculate a discrimination ratio?

Answer 20

(Novel - Familiar)/(Novel + Familiar)

Question 21

Which brain structure is responsible for recognition memory?

Answer 21

Perirhinal cortex

Question 22

How does reinforcement shape behaviour?

Answer 22

Negative reinforcement rapidly reduces response

Positive reinforcement increases response but needs repeated more frequently and numerously

Question 23

What is associative learning?

Answer 23

When an association develops between an unconditioned stimulus and an initially neutral stimulus

Question 24

What is the difference between classical and operant conditioning?

Answer 24

Classical - a stimulus comes to predict an outcome

Operant - sees responses, actions, have a causative role (leads to goal directed behaviour)

Question 25

What is the outcome devaluation procedure?

Answer 25

1. Two responses produce different rewarding food outcomes 2. One food devalued - produces nausea 3. Rats given the opportunity again to press either lever 4. A reduced response for the devalued outcome shows goal direction 5. If press levers equally, responses reflect habit

Question 26

What are the pros and cons of EEG?

Answer 26

Pros: very high temporal resolution, can measure the cortex, non-invasive, painless Cons: low spatial resolution, correlational not causational, potential for false positives

Question 27

How does EEG work?

Answer 27

Shows voltage changes between pairs of electrodes | Amplitude depends on how synchronous activity is

Question 28

How does PET work?

Answer 28

Positrons (+ve charged electrons) introduced into bloodstream Interact with electrons to produce photons Detected by powerful detectors

Question 29

How can PET measure metabolic activity in the brain?

Answer 29

1. Active neurons need more glucose/oxygen 2. Positron isotope of oxygen attached to 2-deoxyglucose 3. Taken up by metabolically active neurons 4. Phosphorylated in neuron, radioactive 2DG accumulates, as does positron emissions 5. Generates an activity map (not anatomical image)

Question 30

What are the pros and cons of PET?

Answer 30

Pros: short scan times, high resolution Cons: radiation exposure (can't scan same person many times), expensive

Question 31

How does MRI work?

Answer 31

Quantifies hydrogen in water/fat of the brain H can be low energy or high energy - many exist in each state MRI uses electromagnetic waves to change H energy states (resonant frequency) H fall from high state to low state, emitting radio waves that are detected

Question 32

What is the physiological basis of fMRI?

Answer 32

As brain activity increases, deoxyhaemoglobin increases Overcompensation occurs Oxyhaemoglobin increases more, signal increases and is detected

Question 33

How are MRI readings analysed?

Answer 33

1. Brains morphed to fit standard template 2. BOLD compared voxel by voxel - t-test for signal intensity for each (mass univariate approach) 3. Ignores patterns across groups of voxels 4. Computationally simple but high false positive rate from multiple comparisons (fixed by region of interest analysis)

Question 34

What are the practical difficulties of MRI?

Answer 34

Signal to noise ratio is poor - can't do a single scan Need multiple activation tasks and continuous scanning Average all results together

Question 35

What are the pros and cons of MRI?

Answer 35

Pros: non-invasive, reasonable amount of anatomical detail, no exogenous ligand Cons: poor temporal resolution (up to 6 seconds for BOLD to appear)

Question 36

What are the two different TMS methods?

Answer 36

Motor evoked potential | Temporary Leisons

Question 37

What is TMS MEP?

Answer 37

Can directly stimulate pathway | Priming - anticipation of movement increases TMS effect

Question 38

What are the different temporary lesions TMS can create?

Answer 38

Short term - single pulse, 1-2cm2 region disabled for up to 50ms Medium term - repetitive stimulation (e.g. 5Hz for 10 seconds), longer lasting and wider ranging effects Offline TMS - 'intense stimuli' can impair function for ~45 minutes

Question 39

What are the pros and cons of TMS?

Answer 39

Pros: very high temporal resolution, high spatial resolution, causal inferences Cons: requires detailed hypothesis