Localisation
Neuroplasticity
Neurotransmitters
Imaging Techniques
Research Methods and Ethics
100
What is the difference between strict localisation and relative localisation?
- Strict Localisation:
- Clear correspondence between psychological functions and brain areas
- All functions can be clearly mapped
- If there is brain damage in that area, there will be deficits in corresponding behaviours
- Relative Localisation: one brain area may be responsible for a function, but not exclusively, and other areas may also take over the function if there is brain damage
100
What is the use it or lose it principle? Give an example to explain.
The brain aims to work as efficiently as possible. The use it or lose it principle relates to neuronal connections.
Neuronal networks that are used, remain and/or increase.
Neuronal networks that are not used, are pruned. They weaken and are lost.
Draganski et al's juggling study.
100
What is a neurotransmitter?
A neurotransmitter is an electrochemical messengers, released from the terminal buttons of a neuron and are only found in the brain and nervous system. They bind to the receptors of post-synaptic neurons and cause either an excitatory or inhibitory reaction, influencing the corresponding behaviour.
100
What mechanism does the fMRI use to produce images?
BOLD - Blood-Oxygen-Level-Dependent
Under the magnetic field, the nuclei align and emit energy, which is picked up by the scanner
Oxygenated and deoxygenated blood have different magnetic properties, which the fMRI scanner is able to detect.
100
Which research methods are most commonly used in studying the brain and behavior?
True/Lab Experiments: Involving animals, brain imaging techniques, ingestion of agonists and antagonists
Quasi-Experiments: Involving specific characteristics of the sample that cannot be manipulated
Case Studies: Unique cases of brain injuries that cannot be ethically replicated on human participants
200
This part of the brain is associated with the flight or fight response and aggression. It also plays a role in the formation of emotional memories.
The Amygdala is located in the temporal lobe and plays a significant role in emotional responses and processing emotional memories.
Sharot et al.'s research observed amygdala activation in participants close to the 9/11 attacks when exposed to word cues related to 'September'.
200
Arrange the following processes for the formation of neural networks:
- Dendritic branching
- Action potential
- Gene expression
- Long-term potentiation
- When a neuron is stimulated, an action potential travels down the axon.
- Neuronal networks are formed when a neuron or group of neurons are repeatedly stimulated.
- This is referred to as long-term potentiation and results in gene expression, which causes the neuron to sprout new dendrites - known as dendritic branching.
- This increases the number of synapses available for the behaviour.
200
List the neurotransmitters we have learned about.
Neurotransmitters: Acetylcholine, serotonin and dopamine, GABA
200
Under what circumstances should researchers use MRI and fMRI/PET, respectively?
MRI - Structural, localization and neuroplasticity
fMRI - Functional, localization of brain activity
200
Why are true/lab experiments used to study the brain and behaviour?
Researchers have control over the experimental environment and can manipulate the IV such as the level of acetylcholine.
This increased control over variables and the environment helps researchers establish cause-effect relationships and understand the role of specific brain mechanisms in isolation.
300
What is the role of the hippocampus?
To convert short-term episodic and declarative memory into long-term memory.
Posterior Hippocampus - Involved when previous learned or encoded memory is being used
Anterior Hippocampus - Involved during the encoding of new environmental information.
Doesn't actually store these memories, just involved in encoding and retrieval. If the hippocampus is damaged, one can expect to experience retrograde amnesia.
300
What is neural pruning? Why does it occur?
- While the brain is capable of developing new neuronal connections, it is also capable of changing when a pathway is no longer stimulated.
- Neural pruning refers to the weakening of neural connections by decreasing the number of synapses available through the reduction of dendritic branches.
- This may be a result of the lack of use of the neural pathway, neuron cell death, chronically increased cortisol levels.
300
Arrange the following in order of neurotransmission:
- Excitatory or inhibitory response is stimulated in the post synaptic neuron
- Reuptake of neurotransmitters or breaking down by enzymes
- Action potential travels down the axon of the pre-synaptic neuron
- Neurotransmitters are released into the synapse
- Pre-synaptic neuron is stimulated
- Stimulates vesicles in the axon containing neurotransmitters
- Action Potential down the axon of the presynaptic neuron
- Vesiscle containing neurotransmitters stimulated -> released into synapse
- Neurotransmitter travels through synapse and bind to receptors of postsynaptic neuron dendrites
- Excitatory or inhibitory reaction
- Neurotransmitters release back into synpase, either undergo reuptake or broken down by enzymes
300
How does bidirectional ambiguity influence the findings from MRI scans? Give an example of research.
Bidirectional ambiguity is a limitation of correlational relationships, wherein it is difficult to establish whether x causes y or y causes x.
MRIs are static images and one can't know for sure if it was a specific experience/behavior that caused the change in structure or whether it was a slight variation in this structure that caused that behavior.
Maguire et al's research, a cross-sectional design, no comparison to before taxi-driving. However, there was a positive correlation between number of years and volume = direction
300
What are some ethical concerns when studying the brain and behavior?
Undue stress and harm
Informed consent
Right to withdraw
400
Why are case studies used to investigate localization?
Unique brain injuries that cannot be ethically replicated in human participants.
400
What is dendritic branching?
When a group of neurons experience long-term potentiation (repeated stimulation of action potential), it causes gene expression and the neuron to sprout new dendrites.
400
What is an excitatory neurotransmitter?
Neurotransmitters can be either excitatory or inhibitory.
Excitatory neurotransmitters excite the neuron.
They depolarise the post-synaptic neuron and allow it to stimulate an action potential.
Acetylcholine and dopamine are excitatory neurotransmitters.
400
What is spatial resolution and temporal resolution?
The quality of a brain imaging technique can be assessed on types of resolution.
Spatial resolution is the ability of a scanner to capture details and differences between nearby locations or parts of the brain. It is a unit of space measured in millimeters that is discernible in a brain scan.
Temporal resolution is the frequency at which a brain scan can register changes in brain activity measured in seconds. Some Temporal resolution is only relevant to scanners that record brain activity, such as the Functional Magnetic Resonance Imaging (fMRI), Electroencephalogram (EEG), and Positron Emission Tomography (PET).
"In a nutshell, spatial resolution refers to the capacity a technique has to tell you exactly which area of the brain is active, while temporal resolution describes its ability to tell you exactly when the activation happened." (Almeida, 2018)
400
Evaluate the ethical considerations of HM's case study.
Informed Consent: Due to his anterograde amnesia, he was unable to provide consent for himself. His family provided consent on his behalf. However, this is problematic as he wouldn't be able to exercise his right as a participant such as wanting to withdraw from the research which went on for 50 years.
Undue Stress and Harm: Extensive research through the rest of his life by multiple researchers.
500
What can we learn about the brain from Maguire et al.'s research on taxi drivers?
The posterior hippocampus is localized to retrieve long-term memories as the taxi drivers had to recall routes to navigate around London.
The brain is plastic and can change with experience.
Repeated stimulation (long-term potentiation) of brain regions can cause dendritic branching, which increases the number of synapses available for specialised skills like taxi driving.
500
What can we learn about neuroplasticity from Draganski et al.'s research?
Formation of Neural Networks: The research supports the ability of the brain to form new networks. When the jugglers started learning the juggling routine, there was increased stimulation of neural pathways in the mid-temporal lobe. As they continued to practice and use that pathway, there was long-term potentiation in that area, causing dendritic branching and the formation of new networks, making more synapses available for that skill as evidenced by the increase in grey matter.
Neural Pruning: When the participants stopped practicing the juggling routine, the neural pathways in the mid-temporal lobe were no longer being stimulated, which causes neural pruning as evidenced by the decrease in grey matter. This reduces the number of synapses available for juggling.
500
What is the difference between agonists and antagonists? Give an example of each and how it may impact cognitions or behaviour.
An agonist is any chemical substance that when bound to a receptor site, causes an excitatory response in the postsynaptic neuron (the next neuron fires an action potential). ACh is an endogenous agonist. Physostigmine - Blocks the production of Cholinesterase, would increase ACh (agonist) level available in the synapse.
Antagonists are any chemical substances that when bound to a receptor site, block out the effects of an agonist neurotransmitter. Scopolamine (Antagonist) - This would reduce the amount of ACh available in the synapse and affect the encoding and retrieval of memory.
500
What are two limitations of brain imaging techniques?
The environment and personal experience of participants may lead to artefacts
2. Expensive, resulting in smaller sample sizes in research
3. Often an indirect measure of brain activity
4. Researcher biases in interpretation
5. Reductionist in that it considers one behaviour or practice to be associated with changes
5. Low ecological validity for PETs and fMRIs
500
Evaluate the ethical considerations of Sharot et al.'s research.
Undue stress and harm: Participants were made to recall memories of a traumatizing experience, the 9/11 attacks. They were also placed in the fMRI scanner, which can cause undue stress and harm as it requires people to remain still in the machine for 30-90 minutes. This would be especially uncomfortable for people with anxiety, claustrophobia, etc.
Must be provided the right to withdraw at any point and debriefed thoroughly, along with follow-up assessments of the participant's mental and emotional state. If necessary, further psychological support must be provided if necessary.