Cognitive Neuroscience

Question 1

What are the challenges for cognitive neuroscience?

Answer 1

Complex systems
Signal to noise ratio
Between-individual differences
Within-individual differences

Question 2

Cognitive neuroscience techniques for brain structures

Answer 2

Autopsy

Structural Magnetic Resonance Imaging (MRI)

Question 3

Cognitive neuroscience techniques for brain function

Answer 3

Scalp-located electrodes (EEG, ERP)
Functional MRI (fMRI)
Magneto-encephalography (MEG)
Transcranial Magnetic Stimulation (TMS)
Positron Emission Tomography (PET)

Question 4

Cognitive neuroscience techniques for neuropsychology

Answer 4

Data from individuals with brain damage

Question 5

fMRI advantages

Answer 5

Location of brain structure used in tasks
Reasonable temporal resolution
Get structural data within same session

Question 6

fMRI disadvantages

Answer 6

Claustrophobic
Noisy
Movement artifacts (difficult for button presses)
Can’t have metal based equipment for stimuli
BOLD isn’t a direct measure of activity and care need to be taken when interpreting it

Question 7

Transcranial Magnetic Stimulation principles

Answer 7

Noninvasive method which depolarises or hyperpolarises neurons in the brain (decrease/increase activity)
Electromagnetic induction induces weak electric currents in the cortex
Can cause motor evoked potential (limb twitches)
Can produce simulated temporary ‘lesion’ of brain region by preventing normal function without any long-lasting adverse effects

Question 8

Who invented TMS?

Answer 8

Tony Barker and colleagues at the University of Sheffield in 1985

Question 9

TMS advantages

Answer 9

Near portable

Can stimulate or lesion

Question 10

Disadvantages of TMS

Answer 10

Difficult to specify precise regions

Only surface regions

Question 11

Magnetoencephalogram (MEG)

Answer 11

Pyramidal cells of cortex, when active, generate significant magnetic field
MEG records this
Synchronous firing of 10000s neurons is required to produce a field large enough to measure
Magnetic fields are less distorted by the scalp than electrical fields

Question 12

Advantages of MEG

Answer 12

Excellent temporal resolution

Good spatial resolution (not distorted by scalp and for the whole brain) especially when combined with MRI

Question 13

Disadvantages of MEG

Answer 13

Expensive

The inverse problem for finding what causes what

Question 14

Electroencephalography (EEG)

Answer 14

Measures electrical signals generated by the brain through electrodes placed at the scalp
EEG signals are produced by partial synchronisation of cortical field activity and are measured as changes in voltage, recorded at the scalp over time

Question 15

Analysis of EEG signals may be…

Answer 15

Task-dependent or task-independent

Question 16

How are EEG signals detected?

Answer 16

Electrodes are placed on the scalp, connected with gel or conductive solution
EEG signals are transported to an amplifier
Amplifier measures the difference in voltage between the active electrode and a reference electrode

Question 17

What is the frequency of measurements in an EEG?

Answer 17

Up to 2000Hz

Question 18

EEG advantages

Answer 18

Very good temporal resolution 
Less subject to motion artefacts
Not claustrophobic 
Can be used by infants 
Major artefacts in eye blinks can be eliminated by monitoring eyelid

Question 19

Disadvantages of EEG

Answer 19

Weak spatial resolution

Inverse problem - given pattern of activity, how do you determine which brain region caused it?

Question 20

Principles of how information travels around the brain

Answer 20

Information received at dendrites
Travels to cell body
Down axon
To the synapse

Question 21

How do we know where early visual processing occurs in the brain?

Answer 21

Using fMRI scans
Occurs in the primary visual cortex (V1)
N170

Question 22

What is an ERP?

Answer 22

An event-related potential

A measured brain response that is a direct result of a specific sensory, cognitive or motor event

Question 23

What is the N170

Answer 23

A component of ERPs that reflects the neural processing of faces in the brain