psychophysiological

Question 1

when is magnetic resonance signal obtained

Answer 1

However, the MR signal is only obtained if hydrogen atoms are aligned in parallel, not when they have random orientations

Question 2

what does the haemoglobin carry

Answer 2

• Haemoglobin carries oxygen to tissues

Question 3

when does BOLD not affect MR signal

Answer 3

• When it has oxygen attached to it (when it is oxygenated), it does not affect the MR signal

Question 4

Mri is an….

Answer 4

indirect metabolic measure

Question 5

what does BOLD fMRI measure

Answer 5

In other words, BOLD fMRI measures blood flow into the active area

Question 6

what is reverse inference in fMRI

Answer 6

If the activation of a given brain area is specifically associated with a psychological process, then finding activation in that brain area indicates the presence of the associated psychological process

Question 7

example of reverse inference in fMRI

Answer 7

acupuncture- if acupuncture lead to an increase in pain, there would be an increase in blood flow in certain brain areas. They saw the opposite so they inferred that it reduces pain

Question 8

Limitations of BOLD fMRI

Answer 8

• The blood flow changes associated neuronal activity are slow
• Hence, although its temporal resolution is superior to that of PET, it is inferior to that of EEG
• People with metal in their body (metal implants, pacemakers, some tattoos) cannot be scanned, because rapid changes of magnetic fields in the scanner heats up metal.
• The space in the scanner is tight- not suitable for individuals with claustrophobia
• The scanner is very noisy- hard to use auditory stimuli and hard to record vocal responses

Question 9

strengths of fMRI

Answer 9

• It is the safest neuroimaging method (compared to PET….)

* It has high spatial resolution

Question 10

what is the problem of causality

Answer 10

• Both electrophysiological techniques and neuroimaging suffer from one serious drawback…
• For a given set of activations or modulations of single-cell activity or ERP components, it is difficult to be certain which (if any) are NECESSARY for a given task/psychological process
• The fact that the activations (or ERP component modulation) co-occur with an experimental condition does not mean that they cause it, or that they are essential for the process to take place…

Question 11

what happens in TMS

Answer 11

• A large current is briefly discharged into a coil of wire held on the subject’s head.
• The current generates a rapidly changing (increasing) magnetic field around the coil of wire and this field passes into the brain.
• In the cortex, the magnetic field generates electric (ionic) current through neurons’ membranes

Question 12

what is TMS often referred to as

Answer 12

virtual lesion technique

Question 13

challenges of TMS

Answer 13

• TMS is associated with strong confounds (‘side effects’), which are not easy to control
• The pulse is associated with a loud sharp noise (‘click’) and with sensations on the scalp and often muscle twitches
• All of these can have profound effects on brain activity and performance
• To control for these effects, one typically has a control condition of stimulating over a brain area that is not involved in the given process
• Need to take into account remote connections of the stimulated area

Question 14

what is EEG

Answer 14

EEG is the change in voltage (electricity) recorded from sensors on the scalp

Question 15

what are ERPs

Answer 15

• ERPs are segments of the EEG, time-locked to particular events stimuli

Question 16

how do u visualise ERP data

Answer 16

ERP data from a visual Lexical Decision Task
Participants presented with words (e.g. TALL and readable strings that are not words, or non-words, e.g. TOLB) and asked to respond with one keypress if the stimulus is a word and with another it is not

Question 17

EEG evaluation

Answer 17

EEG/ERP has high temporal resolution: it can provide detailed temporal information about the processing of a stimulus
The time-course of a particular component (peak) in the ERP along with it scalp topography (map) can be seen as a spatio-temporal ‘signature’ of a certain process or set of processes
However, it has limited spatial resolution (it cannot localise activity in the brain with precision or confidence), due to the complexity of the inverse problem

Question 18

what is chronometric inference

Answer 18

at what point in time following/preceding the stimulus do the experimental conditions start to diverge?

Question 19

what is the fovea

Answer 19

part of retina with the smallest receptive fields (hence, best acuity) and highest concentration of cone receptors

Question 20

what does eye tracking tech rely on

Answer 20

monitoring pupil position by emitting an infrared beam and detecting its reflection from the cornea- the reflection is weaker where the pupil is

Question 21

sampling of eye tracking can be as high as what

Answer 21

1000Hz

Question 22

what is motor threshold

Answer 22

• strength of tms on particular person
• strength that enduces pulses 50% of the time
• allows to adapt strength of stimulation to individuals
• thicker skull can get stronger stimulation