Lecture 2 Flashcards
1
Q
Double Dissociation
A
- allows researchers to determine whether two cognitive functions are independent of one another
- when lesions have converse effects on two distinct cognitive functions
2
Q
Diffusion Tensor Imaging (TDI)
A
- variant of MRI
- measures the movement of water molecules from the brain
- can infer the location of white matter fibres (structural [not functional] connectivity
- connectivity between brain regions
- Often used to compare different individuals brain structure and neurodevelopmental disorders (e.g. ADHD/OCD/ASD
3
Q
Functional near infrared spectroscopy (fNIRS)
A
- optical imaging method (fitbit)
- Shine light in to a substance from diode (brain) to a diode that measures the light coming out. What’s not coming out has been absorbed by the tissue.
- Measures blood flow in the brain (similar to MRI)
- works as haemoglobin and deoxyhaemoglobin have different absorption rates
- cheaper and more straightforward that fMRI, also allows movement (good for children)
4
Q
Electroencephalography (EEG)
A
- EEG measures electrical signals generated by the brain via electrodes placed at the scalp
- Produced by partial synchronisation of cortical field activity and are measured as changes in voltage, recorded at the scalp, over time
- Summation of 10,000s of post synaptic potentials
5
Q
International 10-20 system
A
- international comparison for EEG
- letters represent brain regions
- z is middle line
- O (occipital), P (parietal), C (central), F (frontal), T (temporal)
- odd numbers on left side of face (looking away)
6
Q
Event related potential (ERP)
A
- Time domain analysis (how does the EEG change over time or to an input)
- Provides an indication of brain response to a particular event
- used to inform about cognitive psychology
- The amplitude at a given point can also be plotted as a heat map (shows how ERP is distributed across the scalp)
7
Q
Epoch
A
- Small chunk of the data 100ms from before and after stimulus
- Pink lines represent where you see an event/stimulus
- hard to see difference in one epoch, so an average of many is taken
- when averaged together the random changes (noise/artefacts) in ERP go to 0 (cancels out) as the response to the stimuli is the
- The peaks and troughs show neurons firing at different times (even negative [below 0] still shows activity - just shows where the network is in the scalp, there is still activity)
8
Q
components/deflections
A
Peaks and troughs in components in waveform
9
Q
P
A
positive deflect
10
Q
N
A
negative deflections
11
Q
Amplitude
A
- y axis of graphs
- this is the size of the peak or trough in the waveform
- It is measured in micro volts (uV)
12
Q
Latency
A
- this is the time when a particular feature of ERP (usually a peak or trough) is seen
- It is measured in ms, relative to the onset of a particular event (presentation of stimulus)
13
Q
Visual P1
A
- generated at the lateral occipital cortex
- peaks at around 100ms
- reflects encoding of visual information (increases in amplitude show encoding of visual information)
14
Q
N170
A
- response when looking at faces
- Amplitude of the N1 (N170) view faces compared with other stimuli
- N170 is large over right hemisphere
- Suggestive of a neural mechanism dedicated to detecting faces
15
Q
P300
A
- P3a (novel stimuli)
- P3b (salient relevance stimuli)
