biological terms Flashcards
Case Study:
Case studies are often conducted on people with unique brain damage in specific areas of the brain. These studies allow psychologists to draw conclusions about localization of function.
Case studies are in-depth investigations of an individual, small group or organization. They rely on the use of a number of different methods, both quantitative and qualitative to gather data. This includes observations, questionnaires, interviews and tests. In studies on the brain and behaviour, researchers find participants with damage to particular areas of the brain. They employ a range of methods to gather data on the individual’s behaviour. Any behavioural differences observed between the individual and “healthy” controls allows researchers to draw conclusions about the role of the damaged areas of the brain in that particular behaviour.
Ethics:
Anonymity
Anonymity is keeping the participant’s name private and not revealing any personal information that could lead to the participant being identified. For a study to be ethical, the participant should be able to continue living their life without anyone knowing that they ever participated in this study should they ever be judged or face negative consequences in society due to having their information released. Maintaining anonymity is a way to allow the participant in the study without being ever identified which would allow them to continue living their normal quality of life. In some cases, the participant is not even addressed with a name but instead some sort of code to ensure anonymity.
fMRI
Functional Magnetic Resonance Imaging: measure the activity (or function) of areas of the brain when the participant is performing a task or cognitive process.
-often used in experimental research where the level of a chemical messenger is the IV.
-Participants recieve a treatment –> lay in the fMRI then asked to perform a task. The task they perform is related to the behaviour being studied. Brain activity is then measured while they are performing this task. The researchers can see how chemical messengers can affect activity in certain parts of the brain during certain tasks, like perceiving a social threat.
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especially useful for localisation of brain function studies: psychologists can see which parts of the brain are used when doing certain tasks, help conclude that the activated areas have some function related to the behaviours being performed.
localisation of function
amygdala
-Localization of brain function means particular parts of the brain perform particular functions
-Amygdala is a small almond-shaped part of the brain and is part of the limbic system (located within the temperol lobe + one amygdala on each side of the brain)
-amygdala is called emotion center because of its role in emotion and the stress response
-one key function of amygdala is that it perceives things that are threatening or dangerous and activates stress response.
-Activates HPA-axis –> release of stress hormones like cortisol and adrenaline –> helps experience sensation of fear and trigger a flight or flight response.
neuroplasticity
term used to describe the brain’s ability to change as a result of experience.
-long standing belief our brain development was fixed from a young age.
However, animal research and modern studies using brain imaging technology helped to show how the brain can change throughout our lives.
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Occurs because neurons continually response to the environment.
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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.
neurotransmission
the process of transferring information from one neuron to another at a synapse
An electrical impulse travels down the axon (body) of the neuron. When it reaches an axonal terminal a neurotransmitter is released that then crosses the synaptic gap to the next neuron. Neurotransmitters are stored in a neuron’s terminal buttons. After crossing the synapse, the neurotransmitter fits into receptor sites on the post-synaptic cell, like a key in a lock.
After a neurotransmitter has signalled an electrical impulse in the post-synaptic cell, some types are ‘cleaned up’ by transporter molecules released by the pre-synaptic neuron (reuptake) and they are reabsorbed, re-entering the pre-synaptic cell to be reused. In some cases, neurotransmitters are broken down (degradation)
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neurotransmitters work by sending signals through the brain by binding to receptor sites on neurons and passing on impulses. A neurotransmitter may be excitatory which means it allows the impulse to cross the synapse, or inhibitory, which means it prevents the impulse from crossing the synapse.
-neurotransmitters are affected by agonist and antagonists. an agonist reduces the effect of a neurotransmitter, while an antagonist increases it.
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Serotonin is an excitatory neurotransmitter.
formation of neural networks
The process by which neural networks are formed is called neuroplasticity.
agonist
An agonist is a chemical that amplifies the effect of a neurotransmitter by binding to the receptor sites of that neurotransmitter and activating them. This is opposite of an antagonist which binds to receptors and blocks them from firing. Neurotransmitters have an effect by binding to receptor sites and sending messages through neural networks. Agonists influence this process because they increase the activation of receptors.
But neurotransmitters themselves can be endogenous (naturally occurring) agonists. For example, selective serotonin reuptake inhibitory drugs (SSRI’s) naturally increase the levels and activity of endogenous 5HT (serotonin). Therefore, serotonin can be considered an endogenous (naturally occurring) agonist of 5HT (serotonin) receptor sites. Disruptions to serotonin transmission can influence behaviour.
antagonist
Acetylcholine is a neurotransmitter that plays a role in the formation of memories. It is not possible for researchers to directly observe the role of neurotransmitters, so one of the ways that they attempt to understand the role of different neurotransmitters is by giving animals or human participants an antagonist. They want to see what happens when acetylcholine receptors are blocked and the neurons are “not allowed” to fire.
excitatory or inhibitory synapses
Neurotransmitters play an important role in human behaviour. Neurotransmitters 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.
neural pruning
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.
hormone/behaviour
Hormones are chemical messengers released by glands in the endocrine system and transported around the body in our blood. Various hormones have been identified and associated with different behaviours. One hormone, testosterone, is associated with aggression.
Testosterone is a sex hormone produced in the tests (in males) and to a lesser extent in the ovaries in females), so males naturally have higher levels of testosterone than females.
-aggressive behaviour could serve vital function in maintaining high social status/assert social dominance.
pheramone
MHC
Androstadienone [AND]
Wedekind studied what is known as the Major Histocompatibility Complex, a group of genes that play an important role in the immune system. MHC genes make molecules that enable the immune system to recognize pathogens; in general, the more diverse the MHC genes of the parents the stronger the immune system of the offspring. MHC genes are expressed co-dominantly – that is, that we inherit the MHC alleles from both of our parents and they are expressed equally. It would be beneficial, therefore, to have evolved systems of recognizing individuals with different MHC genes and preferentially selecting them to breed with to maximize immune responses. Evolutionary psychologists argue that our “smell” is the sign of our MHC. Wedekind wanted to see if women are attracted to a man because of his MHC. He did this in his famous “Smelly T-Shirt Study.”
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Androstadienone [AND] is a human steroid that is present in male semen and sweat. It heightens sympathetic arousal, alters levels of cortisol, and promotes positive mood state in females. Androstadienone is also found to activate the hypothalamus in heterosexual females and homosexual males, but not in heterosexual males or homosexual females. Estratetraenol [EST] is the female equivalent of this steroid.
gene - MAOA
Monoamine oxidase A (MAOA) is an enzyme that breaks down neurotransmitters in the synapse
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If they have the low expressing variant it means that there will be less MAOA produced. This can affect neurotransmitter levels (including serotonin and dopamine) which affects brain activity in important parts of the brain, like the amygdala and the prefrontal cortex. This could explain how the MAOA-L affects brain activity.
evolutionary explanation on behaviour
Evolutionary arguments posit that men and women may have different goals when choosing a mate. Males may be fertile for a good part of their lives. When looking for a partner, they would look for a woman with has “high reproductive value.” This is physically obvious: smooth skin, good muscle tone, full lips - and above all, young. Women, on the other hand, are limited in their reproductive ability - both due to age and the fact that they usually only produce one egg per month. According to Trivers (1972), women seek out a partner who will invest in their offspring. In animals, this investment includes providing food and defending the mate and child against predators. In humans, they also aid in the rearing of the offspring and may provide status, power, or resources.
