Lecture 7 - Methods of Interference

Question 1

Interference

Answer 1

When you increase and decrease function in specific brain areas

Question 2

What can we learn by increasing the function of a brain area

Answer 2

Which areas of the brain are sufficient in order for a task to be completed

Question 3

What can we learn by decreasing the function of a brain area

Answer 3

If a brain area is necessary for a function to occur (do you need it)

Question 4

4 methods of interference

Answer 4

Lesions
Electrical stimulation
Optogenetics
Transcranial magnetic stimulation (TMS)

Question 5

Causes of lesions

Answer 5

Injury
Surgery (for epilepsy or psychiatric illness)
Stroke (no blood to brain)
Hemorrhage (too much blood to brain)
Tumor
Congenital
Degenerative disease

Question 6

Broca’s area

Answer 6

• Kid only said the word tan
• Inferior frontal gyrus responsible for language production
• Specific link between brain area and function

Question 7

Phineas Gage

Answer 7

• Damage included orbit of left eye, left frontal lobe of cortex, left and right orbitofrontal PFC
• No initial deficits reported
• Follow up showed drastic changes in personality

Question 8

What happens when you knock out orbitofrontal cortex

Answer 8

Lose control of limbic system –> emotions out of check

Question 9

What happens when you knock out lateral prefrontal cortex

Answer 9

Lose ability to make plans

Question 10

Henry Molaison (HM)

Answer 10

• Most famous neurological patient in history
• Epilepsy
• Doctors decided to remove medial temporal lobe from hippocampus
• Developed severe anterograde amnesia
• Could not make new memories

Question 11

Which part of the amygdala takes in fast sensory info and has output to the sympathetic nervous system

Answer 11

Centra medial

Question 12

What parts of the brain do motor learning

Answer 12

Cerebellum and basal ganglia

Question 13

Why is damage to white matter a problem for interpreting lesion studies?

Answer 13

Damage to white matter damages all of the inputs and outputs

Question 14

Group studies of lesion patients

Answer 14

1. Group by behavioral symptom – can identify multiple regions that are implicated in a behavior (all patients who can’t talk, or who had cortical blindness)
2. Group by lesion location – useful for testing predictions derived from functional imaging and focusing on the role of particular structures (all patients with amygdala damage– very hard in practice

Question 15

Aphasia

Answer 15

Can’t talk

Question 16

Insula

Answer 16

Should you approach this/is this salient to you
When knocked out in cigarette smokers they no longer found cigarettes appealing

Question 17

Lesions – increase activity? decrease activity? invasive?

Answer 17

Decreases activity
Invasive

Question 18

Electrical stimulation

Answer 18

• Electrodes inserted into brain to cause or stop neuronal firing
• Can be done during neurosurgery – awake mapping session while the person does tasks
  – See where a certain action is located in the brain (ex: where music is located in Dan’s brain)
• Example: Penfield diagrams

Question 19

Electrical stimulation – increase activity? decrease activity? invasive?

Answer 19

Increases activity
Decreases activity
Invasive

Question 20

Optogenetics

Answer 20

Goal: to modulate the activity of targeted neurons using light
– Piece together a genetic construct – insert construct into virus – inject virus into animal brain, opsin is expressed in targeted neurons – insert optrode fibre optic cable plus electrode – laser light of specific wavelength opens ion channel in neurons (only express protein in this kind of cell – turn on or off cell based on the color of light)

Question 21

Optogenetics – increase activity? decrease activity? invasive?

Answer 21

Increases activity
Decreases activity
Invasive

Question 22

TMS setup

Answer 22

Use wand to generate a magnetic field – this acts on the neurons underneath it
– Cause neurons to fire by pushing positive charges into the brain (towards cell bodies)
– Prevent neurons from firing by pushing positive charges up (forcing neurons to act in a certain way)
– Excite or inhibit brain areas near the scalp

Question 23

TMS can be used to quiet what brain areas

Answer 23

Areas that are too active

Question 24

FDA approvals for TMS

Answer 24

Major depression
Migraine pain
OCD
Smoking cessation

Question 25

Pros of TMS

Answer 25

• Temporary
• Reasonably focal
• Can be randomly assigned

Question 26

Cons of TMS

Answer 26

• Some areas cannot be stimulated
• Uncertainty over the size of each stimulation area
• May be affecting an excitatory or inhibitory area

Question 27

TMS – increase activity? decrease activity? invasive?

Answer 27

Increases activity
Decreases activity