Brain and Behaviour

Question 1

Imaging techniques

Answer 1

MRI and fMRI

Question 2

MRI

Answer 2

Magnetic Resonance Imaging :

Gives 3d picture of brain structures. Uses magnetic field and radio waves to map activity of hydrogen molecules, which are present in different brain tissue to different degree(S).

Question 3

Advantages of MRI

Answer 3

• Non invasive procedure (minimal harm)
• high resolution image

Question 4

Disadvantages of MRI

Answer 4

• only indicates structure, not actually mapping what’s happening in the brain
• research is correlational in nature, not allowing a clear cause and effect relationship

Question 5

fMRI

Answer 5

Functional Magnetic Resonance Imaging :

Shows actual brain activity and indicates which areas of the brain are active when engaged in a behaviour/cognitive process. Measures changes in blood flow in active brain.

Question 6

fMRI advantages

Answer 6

• higher resolution than PET scans + easier to carry out
• non invasive

Question 7

Maguire (2000)

Answer 7

Aim: To examine whether structural changes could be detected in the brain of people with extensive experience of spatial navigation.

Participants: 16 right-handed male London taxi drivers , 50 right-handed males who did not drive taxis (control)

• Had to complete the “Knowledge” test and have license for at least 1.5 years
• range of ages (not a confounding variable)

Method:
- Correlational (IV is not manipulated)
- Quasi-experiment
- Single-blind (researcher didn’t know whose brain they were looking at)

Procedure:
1) The brain of each participant underwent MRI scans
2) Scans were compared to the control group
3) Data was measured using two different techniques : Voxel-based morphometry (USED TO QUANTIFY THE DENSITY OF GREY MATTER IN BRAIN) and pixel counting (USED TO COUNT PIXELS IN PICTURES PRODUCED BY MRI SCANS)

Results:
- Pixel counting revealed that the posterior hippocampi (taxi driver) was bigger and anterior hippocampi were smaller
- VBM showed that vol. of right posterior hippocampi correlated with the amount of time spent as a taxi driver
- Other regions of the brain did not show any changes

Conclusion:
- Demonstrates the the hippocampus may change in response to environmental demands (with the help of MRI technology)

Question 8

Evaluation of Maguire (2000)

Answer 8

Strengths:
- Quasi : ensured researchers were unable to manipulate IV
- Single blind : avoided researcher bias
- No ethical implications (MRI is non-evasive)

Limitations
- Low generalisability (all male)

Question 9

Sharot et al (2007)

Answer 9

Aim: To determine the role of biological factors on flashbulb memories

Participants:
- 24 people who were in NYC on day of 9/11 attack
- Provided informed consent

Method:
- Quasi experiment (conducted 3 years after attack)

Procedure:
1) Participants were put into an fMRI
2) While in the scanner they were presented with word cues on a screen
3) The word cues were projected along the word “Summer” or “September” (to have participant link the word with summer holidays/9-11)
4) Their brain activity was observed (personal memories of summer served as baseline of brain activity when evaluating nature of 9/11 memories)
5) Participants were asked to rate their memories for vividness, detail, confidence in accuracy and arousal
6) They were asked to write a description of their personal memories

Results:
- only half reported having “flashbulb memories”
- activation of amygdala for participants who were downtown was higher when recalling 9/11 than summer memories
- participants who were further away had equal levels of response in the amygdala when recalling both events
- strength of amygdala activation at retrieval was shown to correlate with flashbulb memories

Conclusion:
- suggest that close personal experience may be critical in engaging the neural mechanisms that produce the vivid memories characteristic of flashbulb memory.

Question 10

Sharot et al evaluation

Answer 10

Strengths:
- No ethical implications

Limitations:
- fMRI : artificial -> low ecological validity
- small, culturally biassed sample size -> low generalisability

Question 11

Flashbulb memories

Answer 11

Occurs when certain memories are stronger than others due to their emotional nature

Question 12

fMRI vs MRI

Answer 12

fMRI :
- modified version of MRI scanner
- captures brain activity
- revolutionised brain mapping (enabling researchers to evaluate brain/spinal cord without invasive procedures or drug injections)
- provides greater insight into how chemical messengers (neurotransmitters and hormones) impact brain activity and behaviour -> could help understand the origins of behaviours such as violence and PTSD

MRI
- spots problems that conventional imaging techniques might miss

Question 13

What is localisation of function

Answer 13

The theory that specific parts of the brain are responsible for specific behaviours or cognitive processes. Specific areas of the brain are responsible for certain tasks, such as language processing, vision, motor control, or memory.

Question 14

Localisation of function and neuroimaging techniques

Answer 14

Advances in neuroimaging techniques such as (fMRI) and (MRI) have allowed researchers to further investigate the localization of function in the brain

Question 15

HM: Milner (1966)

Answer 15

Aim: Investigates the role of the hippocampus on memory formation

Participants:
- 1 participant (HM)
- hit by a cyclist at a young age (sustained a head injury)
- due to debilitating seizures, experimental surgery (remove tissue from medial temporal lobe (including hippocampus) on both sides of the brain

Method:
- Method triangulations (utilising different strategies to carry out research)
- Longitudinal case study

Procedure:
1) Psychometric testing, in which HM was given IQ testing and had above average results
2) Direct observation of his behaviour
3) Interviews with both HM and and with his family members
4) Cognitive testing, where HM had to take part in memory recall tests and learning tasks.
5) An MRI was conducted after all the tests to determine the extent of the damage done to HM’s brain

Results:
-HM could not acquire new episodic knowledge (memory for events) and he could not acquire new semantic knowledge (general knowledge about the world).
- Capacity for working memory
- able to carry on a normal conversation (minimal retention)

Conclusion:
The issue with converting short-term memories to long-term memories can be linked to damage to the hippocampus because this is the region where the neurotransmitter acetylcholine is thought to play a key role in memory formation and learning.

Question 16

Evaluation of HM: Milner

Answer 16

Strengths:
- High ecological validity ( no variables were manipulated + HM was observed in natural environment )
- No ethical implications (consent was given)
- longitudinal: lasted over 50 years (changes could be observed over time

Limitations:
- Not easily replicable
- Retrospective in nature : don’t know a lot about HM’s cognitive abilities before the accident

Question 17

What is neuroplasticity

Answer 17

It refers to the brain’s ability to reorganise and adapt by forming new neural connections and pathways.

The brain’s ability to change in response to internal and external stimuli (fundamental process that underlies learning, memory, and recovery from injury.

Question 18

Neuroplasticity (technical)

Answer 18

Neurons link together to form a new trace in the brain each time we learn something new. This is called dendritic branching because the dendrites of the neurons expand in numbers and link with other neurons.

Question 19

Dragonski (2004)

Answer 19

Aim: Investigate whether learning a new skill would have an effect on the brains of the participants

Participants:
- 24 volunteers (20-24 yrs)
- all non-jugglers

Method:
- FIELD experiment

Procedure:
1) Each participant had an MRI scan at the start of the study to serve as a base rate for grey matter and brain structure
2) Two conditions: jugglers and non-jugglers
- Jugglers were taught a juggling routine. They were instructed to rehearse the routine and to let the researchers know when they were successful
3) The jugglers then underwent a second MRI scan. After the scan, they were instructed to stop juggling, and three months later, a third and final scan was performed
4) Non-juggling group was used as a control group
5) Researchers compared the neural density (grey matter) in the brains of the two conditions using [VBM] to analyse the MRI images

Results:
- No substantial regional variations in grey matter
- @ first stage : mid-temporal region (connected to memory) had more grey matter in jugglers’ brain
- Diminished after three months, many were no longer able to do routine

Conclusion:
Suggested that juggling relies more on visual memory (the perception and special anticipation of moving objects) than on procedural memory which would more likely show a change in the cerebellum or basal ganglia.

Question 20

Evaluation of Dragonski (2004)

Answer 20

Strengths:
- control group
- replicable

Limitations:
- internal validity? : field experiment (home environments most of the time)

Question 21

Studies for brain techniques

Answer 21

Maguire (2000) and Sharot et al (2007)

Question 22

Studies for Localisation

Answer 22

Maguire (2000) and HM: Milner (1966)

Question 23

Rosenzweig et al (1972)

Answer 23

Aim: Investigate whether environmental factors could affect the development of neurons in the cerebral cortex

Participants:
- Rats

Procedure:
1) Rats were divided into three groups at random
- IC: Impoverished condition (no toys and maze) (confined to separate cages)
- CC: Control condition (cage)
- EC: Enriched condition (10-12 rats were housed in a cage with various stimulation items for them to explore and play with)
2) Free and sufficient food and drink for all conditions
3) Rats would spend 30-60 days in their respective environments before they were killed in order for the changes in their brain’s anatomy to be studied.

Results:
- EC and IC had differences
- Cortex of EC was thicker and heavier
- EC rats had more activity in the cerebral cortex neurons involved in acetylcholine transmission (crucial neurotransmitter for memory and learning)

Conclusion:
The thickness of the cortex and the overall weight of the brain can increase when being in an enriched environment

Question 24

Evaluation of Rosenzweig et al (1972)

Answer 24

Strengths:
- Highly controlled laboratory experiment (easier to establish cause-effect relationship)
- Results have been replicated many times, indicating data is reliable

Limitations:
- Difficult to generalise results to humans unless research with humans provides same results
- Ethical concern : unjustified stress/harm

*should undergo cost-benefit analysis in order to see whether goals of the study are worth harm done to animals

Question 25

Studies of neuroplasticity

Answer 25

Rosenzweig et al (1972) and Dragonski (2004) and Maguire (2000) [SAQ]

Question 26

Neurotransmission

Answer 26

Neurons
- one of the building blocks of behaviour
- send electrochemical signals to the brain so that one can respond to stimuli
- the process by which these signals are sent is called neurotransmission.

Question 27

Drugs and neurotransmission

Answer 27

Influence the synapse in two ways: act as agonists/antagonists

Antagonists bind to synaptic receptors but they decrease the effect of the neurotransmitter.

Question 28

What are neurotransmitters

Answer 28

The body’s natural chemical messengers that transmit information from one neuron to another.

Shown to have a range of different effects on human behaviour such as mood, sleep, and learning and memory.

Question 29

Roger and Kesner (2003)

Answer 29

Aim: To determine the role of acetylcholine in memory formation. Acetylcholine is an antagonistic neurotransmitter.

Participants:
- 30 rats

Procedure:
1) Familiarised the 30 rats with a Hebb Williams maze -> placing food in one of the corners.
2) Randomly assigned to one of two conditions: injected with scopolamine or with a saline solution 10 minutes before running the maze.
3) Scopolamine blocks the acetylcholine receptor sites and thus inhibits any response. The saline solution was a placebo injection.
4) Placebo inject -> ensure that getting an injection alone was not responsible for a change in memory. They were made directly into the hippocampus (major role in learning and memory)
5) Encoding of memory was assessed by the average number of errors made on the first five trials of Day 1 compared to the last five trials of Day 1
6) Average number of errors made on the first five trials of Day 2 compared to the last five trials of Day 1 -> assessed retrieval.

Results:
- Scopolamine group took longer + made more mistakes in learning the maze.
- But it didn’t seem to have an effect on the retrieval of memories that had already been created

Conclusion:
Acetylcholine might play a critical role in the consolidation of memory.

Question 30

Evaluation Roger and Kesner (2003)

Answer 30

Strengths:
- Highly controlled lab experiment avec placebo effect -> avoids effect of extraneous variables -> uphold integrity of data

Limitations:
- Difficult to generalise results from animal studies to humans because the results may not be wholly applicable
- Ethical concern

*could lead to the development of treatments for people suffering from dementia or Alzheimer’s disease as they both are memory disorders (assuming that acetylcholine plays a role in memory formation).

Question 31

Antonova et al (2011)

Answer 31

Aim: Investigate whether or not scopolamine affected hippocampal activity in the creation of spatial memory

Participants: 20 healthy males (average age 28)

Method:
- Repeated measures
- Double blind

Procedure:
1) Participants were assigned to one of two conditions at random (scopolamine or placebo injection, 70-90 minutes before participating in the experiment)
2) Scopolamine is an antagonist which blocks acetylcholine receptor sites. This decreases the availability of acetylcholine which assists in encoding memories and learning.
4) The “Arena task” was played by the participants as they were scanned in an fMRI, they were being tested on their capacity to form spatial memory.
5) Before playing the game, the players had training to ensure that they could handle the joystick easily and knew its rules. They participated in the experiment after receiving training.
6) They had to make it through the arena to reach a role, screen would go dark for 30 sec when they reached. They had to practice getting to pole. They were in a different staring position every time.
7) For six trials, the individuals’ brain activity was monitored. The participants returned between 3 - 4 weeks later and redid the test, receiving the opposite treatment to the original study.

Results:
- Scopolamine injections: showed less hippocampal activity

Conclusion:
Acetylcholine could be essential for the human brain’s encoding of spatial memories.

Question 32

Evaluation of Antonova et al (2011)

Answer 32

Strengths:
- Repeated measures: eliminated effect of participant variability
- double blind : avoids researcher bias

Limitations:
- sample size: limiting generalisability
- laboratory experiment: may have affected the stress of the participants which in turn may have affected the brain image results

Question 33

Studies for neurotransmission

Answer 33

Roger and Kesner (2003), Antonova et al (2011)