L10: Interfering with brain function

Question 1

What is the purpose Transcranial magnetic stimulation (TMS)?

Answer 1

Inhibits brain function

Question 2

What is the purpose of Transcranial direct current stimulation tDCS)?

Answer 2

Facilitates brain function.
Ir uses direct electrical currents to stimulate specific parts of the brain.

Question 3

What is brain stimulation?

Answer 3

A non-invasive technique using a magnet coil to induce a voltage or electrodes to induce current into brain tissue.

Question 4

What is the purpose of brain stimulation?

Answer 4

It can be used to investigate the casual function of a target brain area.
If brain stimulation of a specific area either increases or decreases performance, we can assume that area has a causal role in the behaviourwe are observing

Question 5

What does TMs/tDCS do to the neuronal system?

Answer 5

It adds “neuronal noise”, temporarily disrupting or enhancing its function.

Question 6

What happens after the brain function has been manipulated in TMS?

Answer 6

TMS can create ‘virtual lesions’.
Brain regions can become temporarily impaired or disconnected.
This allows us to study their casual involvement in certain brain functions in behaviour.

Question 7

What is the control condition for TMS experiments?

Answer 7

Usually, the same person does the same task at a different time.
‘Sham’ condition - fake pulse is emitted, or a different brain region is affected (ideally not involved in the studied process).

Question 8

How do we test the casual contributions of a brain region to behaviour?

Answer 8

We need to combine the TMS technique with carefully designed behavioural experiments.
If the brain region is casually involved in a certain function, TMS will cause difference in performance (errors) and speed (reaction times) compared to a control condition/

Question 9

What are the main benefits of TMS?

Answer 9

1. Brain research
2. Medical research and application

Question 10

How does TMS contribute to brain research?

Answer 10

Precise localisation of brain regions (at least close to skull)
- Much better localization than experiments with brain lesion patients
- Can also be used in combination with EEG or fMRI
Temporary brain impairment without long term consequences
- Saving a lot of lives of test animals.
- We can study the effect of brain function disruption in the same person.

Question 11

How does TMS help with medical research and application>

Answer 11

Many therapeutic benefits of TMS for many medical conditions including:
- depression
- addiction
- stroke rehabilitation
- Parkinson’s disease
- chronic pain

Question 12

How does tDCS work?

Answer 12

A battery-powered device delivers a constant electrical current of up to 2mA.
Two electrodes on scalp provide different types of stimulation.

Question 13

What are the two types of stimulation with tDCS?

Answer 13

Anode (+) stimulates neuronal activity in brain.
Cathode (-) inhibits brain-cell activity.

Question 14

What are 3 advantages of tDCS?

Answer 14

1. cheap, non-invasive, painless, safe.
2. easy to administer and the equipment is portable.
3. minimal side effects with proper application (common side effect is a slight itching or tingling on the scalp).

Question 15

What are the disadvantages of tDCS?

Answer 15

It’s “too easy, too promising” - meaning its prone to abuse.
The long-term consequences aren’t clear.

Question 16

What 2 things do painkillers do?

Answer 16

1. Depressing the nervous system, making it harder for pain signals to reach the brain.
2. Attaching to opiate receptors to block pain signals coming from the body.

Question 17

How do painkillers work (e.g. aspirin and ibuprofen)?

Answer 17

NSAIDs like Aspirin and Ibuprofen block an enzyme used by injured cells to make prostaglandins (the body’s pain messengers).
When cells don’t release prostaglandins, the brain won’t get the pain message as quickly or clearly.
No known cognitive effects but may protect against neurodegenerative diseases.

Question 18

How do painkillers work (paracetamol)?

Answer 18

Paracetamol (acetaminophen) is not an NSAID and won’t affect the injured cells.
It treats pain by blocking the enzyme receptors in the brain, but not much in the rest of the body, meaning the pain is there but your mind won’t receive the message.
Cognition: can improve spatial memory and decision making, impaired error detection

Question 19

What does your brain do when you are anxious?

Answer 19

It makes adrenaline and noradrenaline (stress hormones).
These make your heart rate faster and make you sweat or shake.

Question 19

What are beta-blockers and what do they do?

Answer 19

Beta-blockers like Propranolol block the effects of these hormones, which reduces the physical signs of anxiety (e.g. decrease heart rate).
Downside - propanol can also suppress positive stress/arousal - loss in libido, erectile dysfunction, and depression.

Question 19

Explain caffeine as a drug + its relation to cognition

Answer 19

Caffeine mimics adenosine (a neurotransmitter that inhibits neural activity and causes drowsiness) and attaches to adenosine receptors in the brain.
When the body runs out of fuel in the form of sugars, adenosine signals the body to become drowsy/tired.
Cognition: improves attention, reaction time, can improve mood

Question 20

Explain nicotine as a drug + it’s relation to cognition.

Answer 20

Nicotine increases the release of dopamine and adrenaline. Dopamine is a reward messenger that causes feelings of pleasure and improved mood.
The rush of adrenaline stimulates the body and causes an increase in blood pressure, respiration, and heart rate, and can result in anxiety.
Cognition: can improve attention, learning, fine motor skills and memory; can also lead to cognitive decline in middle age.

Question 21

What do amphetamines do?

Answer 21

Amphetamines improve sustained attention, reduce overactivity and impulsiveness

Question 22

What do medical and illicit stimulants do?

Answer 22

Increase psychomotor and sympathetic nervous system activity, improve alertness and mood by increasing dopamine & adrenaline.

Question 23

What are the medical and recreational applications of medical and illicit stimulants?

Answer 23

Increase heart rate, constrict blood vessels, dilate pupils, inhibit salivation & digestion, ease nasal congestion, appetite suppression, hyperthermia.

Question 24

What are the cognitive effects of medical and illicit stimulants?

Answer 24

Enhance cognitive control, memory, and attention

Question 25

What is the difference between true and pseudo-hallucinations?

Answer 25

True - perception of images or sounds that are not real.
Pseudo - altered perceptions of things that are real, synaesthesia.

Question 26

What are the cognitive effects of hallucinogens (psychedelic drugs)

Answer 26

perceptual distortions, cognitive restructuring, mood changes, changes in meaning of perceptions, and dissolution of bodily boundaries