SAQ's BIO The Brain and the Behaviour Flashcards
HM Procedure
- HM had epileptic seizures due to an accident with a bike he had at 7 years old, and underwent a treatment in 1953 that removed a part of his brain at age 27. His hippocampus, amygdala, and the adjacent temporal lobe were removed.
- psychological testing, did an MRI to determine the extent of the damage done to HM’s brain, interviews with family
HM Aim
to better understand the effects that the surgery had had on patient HM.
HM Results
- he could not acquire new episodic knowledge (memory of events), or new semantic knowledge (general knowledge about the world). This suggests that the brain structures that were removed from his brain are important for the transfer of information from short-term to long-term memory.
- attacks reduced
- He was able to retain some motor skills exercises, showing the brain stores information in other parts of the brain as well.
Maguire Taxi Study Aim
to see whether the brains of London taxi drivers would be somehow different as a result of their exceptional knowledge of the city
Maguire Taxi Study Procedure
Maguire used 16 healthy right-handed males who were licensed taxi drivers. She compared the taxi drivers to 50 healthy right-handed males who were not taxi drivers. An MRI was used to detect changes in the structure of the brain as a result of their experience.
Maguire Taxi Study Findings
- taxi drivers had larger posterior hippocampi compared to the controls (spatial memory)
- the controls had larger anterior hippocampi compared to the taxi drivers
- positive correlation between the number of years the participants had been taxi drivers and the size of the posterior hippocampus
- negative correlation with the size of the anterior hippocampus
Rogers and Kesner Aim
to determine the role of acetylcholine in the formation of spatial memory.
Rogers and Kesner Procedure
Rogers & Kesner wanted to determine the role of acetylcholine in memory formation and retrieval. They had 30 rats acclimate to a Hebb-Williams maze by placing food in one of the corners. Once the rats were familiar with the maze - and no longer were afraid of the environment - the experiment could begin.
The rats were randomly allocated to one of two conditions. The rats were either injected with scopolamine or with a saline solution ten minutes before running the maze. Scopolamine blocks the acetylcholine receptor sites and thus inhibits any response. The saline solution was a placebo injection. This was done to make sure that the fact of getting an injection alone was not responsible for a change in memory. An injection could result in an increase in adrenaline which would be a confounding variable. The injections were made directly into the hippocampus.
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, whereas the average number of errors made on the first five trials of Day 2 compared to the last five trials of Day 1 was used to assess retrieval.
Rogers and Kesner Findings
The findings were that the scopolamine group took longer and made more mistakes in the learning of the maze - that is, there was a higher average number of mistakes made on the last five trials on Day 1. However, it did not appear to affect the retrieval of memories that had already been created.
Draganski Aim
to see whether learning a new skill - in this case, juggling - would affect the brains of participants.
Draganski Procedure
The participants for this study were 24 volunteers between the ages of 20 and 24. There were 21 females and 3 males. All participants were non-jugglers at the start of the study. Each participant had an MRI scan at the start of the study to serve as a base rate for grey matter and brain structure.
Participants were allocated to one of two conditions - the jugglers and the non-jugglers. Those that were in the juggling condition were taught a three-ball cascade juggling routine. They were asked to practice this routine and to notify the researchers when they had mastered it. At that point, the jugglers had a second MRI scan. After the scan, they were told not to juggle anymore and then a third and final scan was carried out three months later. The non-juggling group served as a control group for the duration of the study.
To analyze the MRI scans, the researchers used voxel-based morphometry [VBM] to determine if there were significant differences in neural density (grey matter) in the brains of jugglers vs. non-jugglers.
Draganski Findings
From the baseline scans - taken before the study began - they found no significant regional differences in the grey matter between the two conditions. However, at the end of the first part of the study, the jugglers showed a significantly larger amount of grey matter in the mid-temporal area in both hemispheres - an area associated with visual memory. Three months after the participants stopped juggling - when many were no longer able to carry out the routine - the amount of grey matter in these parts of the brain had decreased.
Explain one technique used to study the brain in relation to behaviour with reference to one study
“Before the advent of modern technology, psychologists had to rely on studying human behavior through case studies of patients with brain damage or autopsies to understand the brain. In modern times neuro-imaging technology has allowed psychologists to look at a living participant’s brain in a non-invasive way. One such example is the MRI (magnetic resonance imaging), which allows psychologists to look at the structure of the brain. By applying a very strong magnetic field to the brain, the MRI causes the protein spins in hydrogen atoms to align to the magnetic field polarization. Hydrogen is present across the brain as so much of the brain is made of water. A static image is created through a compilation of many different snapshots of the brain. It is possible to create either a 2D slice or a 3D model of the brain. This image indicates the structure of the brain, but it does not provide any indication of function.”
used MRI to understand how HM’s brain functions + changes he underwent
Explain localisation of behaviour, with reference to one study
Neuroplasticity is the brain’s ability to reorganize itself by forming new neural connections. Neuroplasticity allows neurons in the brain to compensate for injury or to respond to changes in the environment. When neurons fire continually as a result of stimulation in the environment, the neurons sprout new dendrites – known as dendritic branching. This increases the number of synapses available for the behaviour. Dendritic branching as a result of stimulation in the environment is seen
in a study by Maguire.
Explain one ethical consideraton in one study of the brain and behaviour
Consent - HM
Informed consent means that before someone agrees to participate in a study, the researcher must explain the purpose and procedure of the study. In addition, the researcher must explain the persons rights - including the right to withdraw and that all data will be kept anonymous. Any potential negative effects of participation must be explained. The biological approach has some problems regarding informed consent:
- animals are often used who cannot give consent
- studes often done on people with brain illness and mental damage (dont fully understand what they are agreeing to)
- complex research = average person might not understand what theyre agreeing to
Explain the use of one research method in one study of the brain and the behaviour
Labratory Experiment, Rogers and Kesner
A lab experiment is done in a well-controlled environment. The participants are randomly allocated to a group unlike in a quasi-experiment where participants are not randomly allocated but instead assigned a group depending on a certain trait (e.g. gender). Lab experiments use a standardised procedure which makes it easy to replicate. These types of experiments make it easy for researchers to manipulate their independent and control variables, helping them to establish a cause and effect relationship. This is essentially what experiments are trying to do - to establish a relationship or lack of a relationship between the independent variable and the dependent variable. In order to see a cause and effect relationship, extraneous variables must be controlled.
Explain neuroplasticity, with reference to one study
Neuroplasticity is the brain’s ability to reorganize itself by forming new neural connections. Neuroplasticity allows neurons in the brain to compensate for injury or to respond to changes in the environment. When neurons fire continually as a result of stimulation in the environment, the neurons sprout new dendrites – known as dendritic branching. This increases the number of synapses available for the behaviour. Dendritic branching as a result of stimulation in the environment is seen in a study by Maguire.
Explain the effect of one neurotransmitter on human behaviour, with reference to one study
One effect of one neurotransmitter on behaviour is the effect of acetylcholine on memory.
Neurotransmission is the process where neurons communicate with other neurons. This is done when the presynaptic neuron releases chemicals called neurotransmitters to cross the gap between two neurons called the synapse. These neurotransmitters then bind to specific receptor sites on the postsynaptic neuron, releasing an electrical signal called the action potential. If these receptor sites are blocked by another chemical, the postsynaptic neuron will not be able to release the action potential, inhibiting the process of neurotransmission. This is a common way of studying the effects of neurotransmission. If the receptor site is blocked by an antagonist, for example scopolamine, the neurotransmitter is not able to bind with the receptor site.
Explain the role of one antagonist with reference to one study
An antagonist is any substance that fits into a receptor site on the post synaptic neuron, inhibiting the neuron. This inhibts the firing of the neuron, meaning the behaviour will not happen. Neurotransmitters are often observed through the inhibition of certain neurotransmitters, meaning the use of antagonists. An example of a neurotransmitter is acetycholine, which plays a role in the formation of memories. Scopolamine is an antagonist which is often used in memory research.
Explain the formation of neural networks with the use of one study
The process by which neural networks are formed is called neuroplasticity. When a neuron is stimulated, an action potential (an electrical charge) travels down the axon. Neural networks are created when a neuron or set of neurons are repeatedly stimulated.
When neurons fire continually as a result of stimulation in the environment, the neurons sprout new dendrites – known as dendritic branching. This increases the number of synapses available for the behaviour. Dendritic branching as a result of stimulation in the environment is seen in a study by Maguire.
Explain neural pruning/neural plasticity with reference to one study
Neuroplasticity is the process by which our brains adapt to changes in the environment. One of the ways that our brains change is through the creation of neural networks. This happens because of long-term potentiation - that is, the repeated firing of neurons. This leads to an increase in dendritic branching which leads to an increase in the number of synapses. Another way that our brain can change is through neural pruning - which is a decrease in the number of synapses as a result of the removal of dendritic branches. Pruning can be the result of neuron cell death, hormones such as cortisol, or the lack of use of a neural pathway. The exact mechanism of neural pruning is not yet fully understood.
Explain the role of one agonist with reference to one study
An agonist is any chemical that binds to a receptor site on a post synaptic neuron, causing the neuron to fire. Neurotransmitters are endogenous agonist — the brains natural chemical that bind to receptor sits, leading to an action potential. An example of an agonist is acetylcholine.
Explain the role of inhibitory or excitatory synapses in one behaviour with reference to one study
Neurotransmitters play an important role in human behaviour. They are released from the terminal buttons of a neuron and then travel across a synapse where they attach to receptor sites on the postsynaptic membrane.
Some neurotransmitters are seen as more excitatory — that is, they make the target neuron more likely to “fire” an action potential. A neurotransmitter can sometimes have either an excitatory or an inhibitory effect, depending on the receptor sites that it binds to. One example of how a neurotransmitter binds to excitatory receptor sites is the role of acetylcholine in the formation of spatial memories.
Maguire link sentence
Maguire argued that this demonstrates the plasticity of the hippocampus in response to environmental demands. She argued that the posterior hippocampus stores a spatial representation of the environment and that in the London taxi drivers, the volume of the posterior hippocampus expanded because of their high reliance on navigation skills and spatial memories.
Rogers and Kesner link
The hippocampus is where STM is transferred to long-term memory; it is also where there are many acetylcholine receptor sites in the brain. Although this study was conducted on rats, spatial memory is associated with the hippocampus in both animals and humans, so this finding helps us understand how antagonists like scopolamine may negatively affect human memory too - for example, when navigating through a new school or learning directions in a new city.
