3.1 content (biological) Flashcards
what are genes?
instructions on how to make proteins
what are hormones?
- chemical messengers that travel in the blood
- it is slow
what are neurotransmitters?
- chemical messengers that act in the synapse
- very fast
what is the definition of aggression?
- behaviour that is intended to cause injury, both physical and psychological
- way to assert or maintain dominance
what is the frontal lobe responsible for?
for higher order reasoning, decision making and impulse control
what is the parietal lobe responsible for?
sensation and movement
what is the temporal lobe responsible for?
emotion and memory processing
what is the occipital lobe responsible for?
vision
what is the limbic system?
- contains amygdala which regulates emotional responses
- role in memory and learning
- connects cortical and subcortical regions of the brain
what does the hypothalamus do?
- hunger, thirst and sex motivational drives
- role in body’s fight or flight stress response
- maintains functions in the endocrine system by secreting hormones and manipulating pituitary gland
what does the spinal cord do?
- long, tubelike structure that starts at the end of brain stem and finishes at the bottom of the spine
- consists of nerves that carry messages between the brain and rest of body
what is the function of cell body in a neuron?
contains nucleus which contains the genetic material of the cell
what is the function of dendrites?
- receives neurotransmitters from neighbouring neurons towards the cell body
- it has receptors which bind to specific neurotransmitters
what is the function of the axon?
- tube like structure that carries an electrical impulse in the cell body
- impulse generated in the axon hillock
what is the function of the myelin sheath?
insulate the axon and make impulses travel faster
what is the function of terminal buttons?
- ends of the axon
- involved in communicating with neighbouring neurones by releasing neurotransmitters into the synapse
what’s the function of a neurone vesicle?
neurotransmitters are stored here
what are the steps of neurotransmitters travelling through neurons?
- dendrites have receptors which receive neurotransmitters, they are attached to the cell body
- electrical impulse travels down the axon, it is generated at the axon hillock
- axon is covered in myelin sheath which speeds up impulses
- it travels down the terminal button. terminal button has vesicles filled with neurotransmitters
- neurotransmitters diffuse down the synapse
what is the function of a sensory neuron?
carries sensory information from the body to the brain
what is the function of the motor neuron?
carries signal from the brain that makes muscles in the body move
what is the relay neuron?
connects to motor and sensory neurons
what is excitation?
signals from neighbouring neurones that make the neuron’s charge more positive
what is inhibition?
signals sent from neighbouring neurones that make the neurons charge more negative
what is cancellation?
excitatory and inhibitory signals from neighbouring neurones cancel each other out
what is spatial summation?
many neighbouring neurones send excitatory signals to the neurone
what is temporal summation?
one neighbouring neurone send many excitatory signals to the neurone
how does cocaine work?
- affects the dopamine reward system in the brain
- mimics the structure of dopamine molecules and blocks receptors at the terminal buttons leading to dopamine molecules staying in the synapse
- leads to a large build up of dopamine binding to the postsynaptic neurone
- person feels pleasure but it leads to body’s dopamine system being deregulated leading to weight loss and dry mouth
how does heroin work?
- affects endorphins and natural painkillers in the brain
- mimics structure of endorphin molecules in the neurons, leading to many mu receptors being activated
- this produces excess levels of endorphins leading to pleasure experienced by the person
- leads to pain after being high as body lowers the endorphin levels to compensate
what’s the function of the amygdala?
- part of the brain that processes emotion regulation and motivation
- plays a central role in how an organism assesses and responds to threats and challenges
- coccaro found that people who have extreme aggression show much higher levels of amygdala activity
how does the frontal lobe (prefrontal cortex) link to aggression?
- governs most social interactions and regulates behaviour
- ability to control impulses is associated with it
- raine found that murderers had higher levels of activation in their amygdala but lower in the prefrontal cortex
how is the hypothalamus linked to aggression?
- produces the fight or flight response and activates the sympathetic nervous system + adrenal-cortical system
- sympathetic nervous system speeds the body up and it becomes alert
- adrenal-cortical system leads to adrenaline being released which increases heart rate
what is serotonin and how is it linked to aggression?
- inhibitory neurotransmitter
- normal levels of serotonin are associated with reasonable levels of self control
- low levels of serotonin are related to lower levels of control and more violent impulses such as aggression
what is dopamine and how is it linked to aggression?
- neurotransmitter that gives experiences of reward
- increased level of dopamine overall increased aggression but when combined with a lower level of serotonin the aggressiveness increases even more
what is localisation of function?
specific areas of the brain are involved in specific tasks, such as amygdala being responsible for threat perception
what was the aim of raine’s study?
to investigate whether the brain areas of the prefrontal cortex, angular gyrus, amygdala, hippocampus, thalamus and corpus callosum were related to violent behaviour
what’s the role of the hippocampus
helps with learning and memory
what’s the role of the thalamus?
relays sensory and motor signals to and from the brain
what’s the role of the corpus callosum?
connects left and right cerebral hemispheres
who were raine’s participants?
- 41 murderers who used the NGRI defence in their trials
- 41 age, ethnicity and sex matched controls to each murderer
what was the procedure of raine’s study?
- each participant was given a radioactive tracer injection into their blood
- tracer chemical will make areas of the brain undergoing metabolism light up
- 32 mins after tracer is injected, participants have to do tasks on a computer, moving a button etc.
- tasks activate areas in the brain researchers are interested in
- after the tasks a PET scan was taken and took 10 images of tha brain at 10mm intervals
what were the results for raines study?
- murderers had less activity in the prefrontal cortex than the controls
- graphs to show less glucose level for murderers
what was the conclusion of raine’s study?
-murderers who were pleading NGRI have different brain activities than people who were not violent offenders
- suggests that no single brain area is related to violent behaviour but various areas interact together to lead to violent behaviour
what’s a strength of raine’s study?
- high levels of control
- standardised procedures were used (same tasks) , participants were drug tested and the PET scanning method were consistent across participants
- therefore, the internal validity of the study was high, confounding variables were all controlled
what’s a weakness of raine’s study?
- some key elements weren’t controlled
- 23 of the murderers had suffered from head injuries which could’ve explained the differences in corpus callosum activities
- situational factors like upbringing could have also affected the brains of the participants
- therefore, researchers cannot be absolutely certain that other factors other than brain structure could have lead to violent behaviour
how is testosterone linked to aggression?
- linked to fight or flight response
- hormone linked to aggression
how’s cortisol linked to aggression?
- hormone produced in the adrenal gland
- manages stress levels which inhibits aggression
what’s a strength of hormonal explanations for aggression?
- Dabbs et al
- measured testosterone in saliva of 692 adult male prisoners and he found higher levels in rapists and violent offenders
- therefore, testosterone is linked to aggression
what’s a weakness of hormonal explanations for aggression?
- evidence is correlational
- research just considers the changes in hormone levels in association with changes in aggression, without manipulating hormone levels to see if they cause changes in aggression as it’s unethical
- therefore, impossible to establish a casual relationship meaning there could be alternate explanations such as increased testosterone levels
what’s natural selection?
- some mutations are better suited for the environment the living thing is in
- those with useful mutations survive better in that environment and more likely to pass on their genes
- traits and behaviours are adapted and changes in species over time
hows aggression useful as an evolved trait?
- helped our ancestors gain territory and resources
- used in hunting and providing food for others
- scare off potential competitors or fight for resources for survival
- males have developed strategies for guarding their female partner so that their genes are passed on and not the rivals’
what’s a strength of evolutionary explanations for aggression?
- Chester
- found that in 277 male and female participants, lower functioning MAOA genes lead to less inhibition and self control — more aggression
- therefore, it supports evolutionary theory as aggression can be linked to inheriting certain genes
what’s a weakness of evolutionary explanations for aggression?
- Wolfgang
- found that kung san people have very low levels of aggression as behaviour is discouraged from childhood
- therefore, aggression can be outweighed by cultural norms
how are CT scans done?
- uses X rays that pass through the brain in multiple angles
- computer creates an image of the brain
- measures what areas of the brain are damaged or where tumours are positioned
what are the risks with a CT scan?
damage unborn babies
what are the advantages of a CT scan?
- very quick to conduct showing accurate details of brain structure
- quality can show tumours or structural damage that could lead to better understanding of the area
what are the disadvantages of a CT scan?
- can’t tell you about how the brain is functioning and only provides structural information
- limited use in research linking brain areas to specific behaviours
how does a PET scan work?
- injected with radioactive tracers that is absorbed into bloodstream and binds to glucose molecules in the blood
- high conc. of gamma rays found in areas of high activity in images
- measures glucose levels in the brain: more glucose used = more activity
what are the risks of a PET scan?
low risk but is unclear whether there will be long term effects
what are the advantages of PET and MRI scans?
- indicate specific areas of the brain involved in an experience
- provide evidence of localisation of function
what are the disadvantages of PET and MRI scans?
low mundane realism —> tasks done by patient artificial and not everyday tasks
how do MRI scans work?
- very powerful electromagnet is used, blood cells with oxygen will repel magnet but ones with no oxygen will follow it
- areas of the brain that use more oxygen are more active and you can see which areas are being used in tasks
what are the risks of an MRI scan?
people who have metal surgical implants and pacemakers cannot go through an MRI
what are overall benefits of using brain scans?
- reliable and objective ways to measure brain activity or structure
- we can establish connections between brain areas and behaviours by comparing measurements against behaviour
what are the overall issues with using brain scans?
- tasks are generally low in mundane realism and may not trigger or activate the brain in the same way real behaviour would
- e.g activity on a computer vs being aggressive irl
- therefore, findings on brain activity may not be applicable
what are the two components of the id?
Eros: a desire to preserve life and enjoy it
Thanatos: a drive towards death and destruction
what’s the id’s role?
- stands for inner drive
- formed from the desires of Thanatos and Eros with no thought for consequences
- pleasure principle: to gain pleasure or satisfaction of urges asap
- eros eg = food, thanatos eg = aggression
what’s the superego’s role?
- socialised part of your personality developed through the way you were raised
- morality principle: socialised understanding of what’s right and wrong
- demands you to follow your morals, if someone follows their id they will feel guilty but if they control then they’ll feel pride
what’s the ego’s role?
- driven by the understandings of reality
- urges of the id cannot always be immediately satisfied
- reality principle: understanding what’s socially or realistically acceptable to achieve
- redirects id’s desires to a more realistic behaviour: sublimation and/or displacement
what’s displacement and sublimation?
displacement — when aggression towards someone is not acceptable so you redirect it towards someone more acceptable (eg younger sibling)
sublimation — when someone displaces their emotions in a socially acceptable way (eg ranting in ur notes app)
what’s a strength of freud’s explanation?
- Graham
- those who ranted and processed emotions and aggression had an improvement in control over pain
- therefore, processing aggression can be beneficial in the long term
what’s a weakness of freud’s explanation?
- freud’s concept of letting off steam has been shown to actually heighten aggression by bushman
- 600 students got angry because a confederate heavily criticised their essays
- students who were allowed to release anger by hitting a punching bag were the most aggressive with confederate
- therefore, venting can heighten aggression and lead to antisocial behaviour
