measuring brain activity and artificial brain modification

Question 1

what is brain imaging’s aim

Answer 1

to assess brain structure and function “non-invasively” without dissection or damage to the brain

Question 2

what can neuropsychological methods infer

Answer 2

function from patients that have already experienced brain damage but is difficult to identify similar patients and replicate findings

Question 3

what is Electroencephalography (EEG)

Answer 3

refers to both electroencephalography (equipment/method) and electroencephalogram (data output - “writings of electricity from the head”)

Question 4

wjat are the strengths of EEG

Answer 4

• good temporal resolution
• relatively cehap
• portable and pssible to record while people are moving around
• safe and well tolerated by participants - no real risks associated with placing recording electrodes on a person, beyond mile discomfort
• participants typically have few concerns or fear

Question 5

what are EEG limitations

Answer 5

• poor spatial resolution
• typically only detects activity on the surface of the cortex

Question 6

what is electrophysiology (single neuron)

Answer 6

• hodgkin and huxley (1952) - recorded action potential

Question 7

what are the strengths of electrophysiology

Answer 7

• records directly from individual neurons so is the best method to use if you want to know what the neurons are doing

Question 8

what are the limitations of electrophysiology

Answer 8

• high risks of infection as this technique is invasive as it penetrates the brain
• neurons don’t work in isolation but rather as large networks

Question 9

how does MRI work?

Answer 9

• exploits the magnetic properties of brain tissue
• generates a very strong magnetic field
• magnetic field passes through the person’s head causing hydrogen atoms to align with the magnetic field
• radio frequency waves temporarily disrupt this alignment causing a signal that can be detected by this machine
• different areas of the brain emit different signals because of their H20 content
• analysis signal software converts detected signals into very detailed images of different structures in the brain

Question 10

what is fMRI (functional imaging)

Answer 10

• cognitive processes use energy
• oxygenated blood
• deoxygenated blood
• first observed by Seiji Ogawa in 1990
• as the is used blood flows to the specific region

Question 11

what are the strengths of MRI

Answer 11

• high spatial resolution
• identifies anatomical/structural and functional properties of different brain regions

Question 12

what are the limitations of MRI

Answer 12

• very expensive
• very large equipment and specialist facility required
• safety risks
• specialist staff

Question 13

what is Positron Emissions Tomography (PET)

Answer 13

• uses radioactive substances knowns as tracers to visualise glucose metabolism or the neurotransmitter/receptor function
• radioactive tracers can be used to bind selectively to proteins of interest
• currently used as a diagnostic tool for Alzheimer’s disease

Question 14

what are the strengths of PET

Answer 14

• detect different chemicals in the brain associated with either the metabolism or functional properties such as specfic neurotransmitter levels or proteins

Question 15

what are the limitations of PET

Answer 15

• expensive
• requires specialist facilities and staff
• low spatial resolution
• requires radioactive tracers to be injected into blood - can be risky`\

Question 16

what are the different types of brain modification

Answer 16

• permanently removing/destroying the brain activity
• areas can be stimulated to enhance or increase brain activity in region

Question 17

what does modifying the brain with medical treatment do?

Answer 17

drugs can be used to selectively target abnormal function of specific neurotransmitter systems

Question 18

what does enhancement of brian function refer to

Answer 18

improvement of healthy function to above or better than normal

Question 19

how do scientific research and brain modification relate?

Answer 19

• brain modulation offers powerful tools for research
• unlike fMRI which provides correlational info, brain modulation provides information about causation and whether a given brain region is necessary for a particular task

Question 20

what is an ablation study?

Answer 20

• ablation = “to carry away”
• deliberate lesions allow a relatively high degree of precision

Question 21

what was the prefrontal leucotomy

Answer 21

• introduced by Egas Moniz
• based on studies that removing the frontal lobes of chimpanzees made them calmer and more cooperative
• while patients weren’t always positive, they were considered to still outweigh the negative symptoms being experienced

Question 22

what were the two og processes for frontal leucotomy

Answer 22

• leucotome inserted into one of several holes drilled in the skull, with its cutting wire retracted. wire was extruded from the tip and the leucotome rotated to remove a core of tissue
• or, cutting implement was inserted above the eyelid, pushed through the base of the skull, and rocked from side to side to slice through the frontal lobes, separating them from the rest of the brain

Question 23

what were the initial improvements of frontal leucotomy

Answer 23

• widespread use
• shown to be ineffective

Question 24

what were the profound personality consequences

Answer 24

• apathy
• emotional unresponsiveness
• disinhibition
• inability to plan

Question 25

what is electrical brain stimulation

Answer 25

• used to reveal precise localisation of cortical function
• Fritsch and Hitzig electrically stimulated part of the frontal cortex in dogs; induced contractions of specific muscles on the opposite side of the body
• surgical removal of ‘motor’ regions of cortex performed by the relevant limb

Question 26

what is non-invasive electrical brain stimulation - ECT

Answer 26

• invented in Italy 1930s
• already known that seizures reduced psychiatric symptoms
• ECT originally used to treat a range of mental illnesses
• mechanism of action is unknown

Question 27

what is non-invasive magnetic brain stimulation - TMS

Answer 27

• coil carrying electical current generates brief, focal magnetic pulse which activates a small region of cortex
• activation acts like a ‘virtual lesion’ temporarily disrupting the tissue for a few fundred milliseconds

Question 28

what are the four neuroethics questions?

Answer 28

1. should different methods be treated equally?
2. who should regulate the use of brain modifying techniques?
3. should we have right to modify our own brains if we chose?
4. should soem capacities be treated differently to others?