Week Three - Brain Stimulation/Motor Function

Question 1

How does TMS work?

Answer 1

Via a production of a voltage across an electrical conductor due to its dynamic interaction with a magnetic field

Question 2

The usefulness of TMS?

Answer 2

Non-invasive procedure
Temporal Specificity = excellent
Spatial specificity = Ok
Can be used in conjunction with motor tasks/cog tasks to actually explore neural mechanisms of behaviour

Question 3

Safety of TMS?

Answer 3

Some adverse effects:

• Headache
• Light-headedness
• Nausea

Question 4

3 main uses of TMS

Answer 4

1. Assessment
2. Disruption
3. Modulation

Question 5

Explain the use of TMS for Assessment?

Answer 5

• corticospinal excitability
• intracortical inhibition
• connectivity

Question 6

Using TMS as a Modulation technique?

Answer 6

TMS induced neuroplasticity (excitability vs inhabitability)

Question 7

High Frequency TMS vs Low Frequency TMS in Modulatory TMS?

Answer 7

HF = LTP-like plasticity
LF = LTD-like plasticity

Question 8

How can we use rTMS to reinstate balance after a stroke?

Answer 8

LF rTMS to contralesional hemisphere to reduce excitability

Question 9

TMS and Parkinson’s Disease?

Answer 9

For motor symptoms:
HF rTMS to SMA or m1 - not strong evidence

For depression: rTMS to DLPFC - probable efficacy

Question 10

TMS and Dystonia?

Answer 10

Loss of inhibition and excessive plasticity have been treated with LF rTMS (cTBS) to try and reset levels of inhibition and counteract excessive plasticity - insufficient evidence

Question 11

TMS and Tourette’s/Ticks?

Answer 11

SMA is involved in movement preparation and organisation of self-initiated movements - some evidence that LF rTMS to SMA reduces tic severity

Question 12

Why are rTMS effects not impressive for the treatment of movement disorders?

Answer 12

Areas of the brain don’t work in isolation so hard to pinpoint certain areas to affect.

Question 13

TMS and Depression?

Answer 13

The better alternative to ECT
- HF repetitive TMS to the left DLPFC
- LF repetitive TMS to the right DLPFC
Endorsed by Psychiatrists

Question 14

tDCS?

Answer 14

Two electrodes on different areas of the brain to create electric currents, inducing LTP or LTD like plasticity through shifts in membrane potential of the underlying tissue and changes in synaptic plasticity that mimic LTP and LTD

Question 15

Negative of tDCS?

Answer 15

Can only be used to induce neuroplasticity, they do not measure excitability or inhibition

Question 16

What do we NEED TMS for?

Answer 16

To assess the physiological outcome of tDCS and to look at the behavioural effect of tDCS

Question 17

What is Electrodoping?

Answer 17

The use of brain stimulation to enhance cognitive performance in the healthy population