TMS

Question 1

What are the loading times and discharge durations of TMS?

Answer 1

Loading times ~100-200 microseconds

Discharge durations <1 millisecond

Question 2

What are the four applications of TMS in research?

Answer 2

Neual noise, virtual lesion, probing excitability and information transfer approaches

Question 3

How does the injection of neural noise approach work?

Answer 3

Single pulse TMS is applied to a specific region of the brain. Can reveal the causal involvement of a region.

Question 4

What did the Amassian et al study find using the neural noise approach?

Answer 4

Found that during a critical period (40-120 ms) stimulation affected detection of the 3 letters. Was contra-lateral

Question 5

What is the virtual lesion approach to TMS?

Answer 5

Repetitive TMS is used to measure whether (and for how long) a cognitive task is impaired. rTMS inhibits cognitive functions longer

Question 6

What is the probing excitability approach to TMS?

Answer 6

Single pulse TMS is applied (usually over M1). We measure how strongly the area of interest reacts (how strong its output is) after TMS pulse

Question 7

How is the excitability of the M1 measured?

Answer 7

Through Motor Evoked Potentials (MEPs) using an EMG. Average MEPs are compared between two experimental conditions.

Question 8

What is the probing information transfer approach to TMS?

Answer 8

Uses paired-pulse (1st pulse- subthreshhold 2nd pulse supra-threshhold) TMS and compares how 1st pulse influences effect on 2nd. Can reveal info transfer between 2 regions

Question 9

What is the null hypothesis? And how can we reject it?

Answer 9

Null hypothesis argues that the IV will not affect the DV. Further argues results are due to chance. Can reject with a t-test and a small enough p value (usually 0.05 or lower)

Question 10

Name one advantage and disadvantage of a one sample design

Answer 10

Advantages: being able to compare data to known population value

Disadvantages: unable to compare two groups or across a timespan

Question 11

Name one advantage and disadvantage of a independent measures design

Answer 11

Advantage: measurements are independent

Disadvantage: differences in groups with low sample size can affect results

Question 12

Name one advantage and disadvantage of a repeated measures design

Answer 12

Advantage: can study a change over time

Disadvantage: measures are not independent (variance calculations are different)

Question 13

What is electroencephalography (EEG)?

Answer 13

Method of detecting neural activity. Small electrodes on scalp pick up small fluctuations of electrical signals from neurons.

Question 14

Name an advantage and disadvantage of EEG

Answer 14

Advantage: relatively cheap to perform

Disadvantage: poor spacial resolution (can only show activity of groups of neurons)

Question 15

EEG signals have a typical amplitude of 10-100 microvolts. Why is this important?

Answer 15

This signal is too small and must be amplified by a factor of 1,000 - 100,000

Question 16

Is the orientation of the neurons important in EEG?

Answer 16

Yes, if the dipoles of the activated neurons are not facing the scalp, the signal cannot be recorded

Question 17

What is an event-related potential (ERP)?

Answer 17

A measure of brain activity obtained by time locking signals to events we want to study so we can analyse the signal amplitude at specific channels

Question 18

What is a shortcoming of ERPs?

Answer 18

ERPs often indicate more than one process and researchers might disagree which interpretation is correct