Methods

Question 1

Briefly describe how TMS works.

Answer 1

A stimulator containign a coil of wire is placed above the scalp, a high electrical current is fed through the coil resulting in a magnetic field, perpendicular to the plane of the coil.

Question 2

In TMS, the magnetic field induces what type of field perpendicular to the magnetic field?

Answer 2

an electric field

Question 3

Why is TMS called trans-cranial?

Answer 3

because the electric field outside the brain leads to neuronal excitation inside the brain

Question 4

With TMS, which type of cortex stimulation produces challenging results?

Answer 4

Auditory cortex stimulation

Question 5

What is chronometry?

Answer 5

the science of accurate time measurement

Question 6

Single pulse TMS research using blind subjects showed that the visual cortex contributes to tactile information processing. What is this an example of?

Answer 6

crossmodal plasticity

Question 7

TMS that uses chronometry, uses a single pulse. Whereas, TMS that uses virtual lesions uses ______

Answer 7

repetitive TMS

Question 8

Repetitive TMS produces a virtual ____ by temporarily inhibiting brain areas?

Answer 8

lesion

Question 9

Virtual lesions created using TMS showed error rates in different brain regions for blind and sighted ppts. What were they?

Answer 9

Blind ppts: max error rates after the occipital virtual lesion

Sighted controls: max error rates after anterior parietal virtual lesion

Question 10

What are some advantages of TMS?

Answer 10

Good temporal resolution in millisecond range, short duration minimises risk of plasticity, repeated studies in the same subject & you can study double dissociations.

Question 11

What are some disadvantages of TMS?

Answer 11

spatial undersampling (only one area at a time), only cortical areas accessible and auditory cortex is problematic.

Question 12

EEG measures electrical activity generated by ________ potentials?

Answer 12

postsynaptic

Question 13

Neurons are aligned perpendicular to cortical surface. Which part of the neurons are closest to the surface?

Answer 13

dendrites are close to the surface and axons are close to white matter.

Question 14

Averaging _______ the signal-to-noise ratio of the ERP signal

Answer 14

increases

Question 15

Describe exogenous ERP’s.

Answer 15

automatic responses of brain, controlled by physical properties of the stimulus

Question 16

Define endogenous ERP’s

Answer 16

reflect interaction between subject and event ( attention task-relevance)