Hormones, Neurotransmitters And Drugs Flashcards
Phineas Gage (1848)
- trampling iron went through his frontal lobe
- injury to it can influence aggressive behaviour
- survived but personality changed and molested children
What is the amygdala
Processing memory and emotional reactions
If the amygdala is damaged…
…emotional reactions will not be regulated
Kluver-Bucy Syndrome
- destroyed amygdala in monkeys
- found them to have reduced aggression after the psychosurgery
Mark and Erwin (1970)
- study if a female patient after electrical stimulation to amygdala
- flung herself into wall afterwards and became very angry
- increased aggression
Wong et al (1997)
Criminals with violent tendencies have reduced sized amygdalas
What is the role of the pre frontal cortex?
Regulates the emotional responses driven by the amygdala
Damage to the pre frontal cortex..
… results in impulsivity, immaturity and loss of control
Anderson (1999)
Damage to the pre frontal cortex during infancy resulted in aggressive behaviour in adult life
What is a neurotransmitter?
Chemical messengers that act between the neurones of the brain which allows the brain to process thoughts and memories
What is a neurone?
Receive and transmit messages, passing them from cell to cell
What is the neurones axon?
The path that the impulse travels down
What is a synapse
The site of transmission of electrical impulses between two neurones
What is Action Potential?
Electrical impulse
What is the pre-synaptic neurone?
Creates action potential (electrical impulse)
Explain the travel of dopamine
- dopamine is released from the axon terminal
- goes through neurotransmitters diffusing through the synapse to another neurone
- signal is received in the dendrite of the dopamine receptors
What is re-uptake
When neurotransmitters do not get received by the dendrite so they travel back and are taken in again by the axon terminal where the electrical impulses were released
What is Depolarisation
The temporary reversal of changes on the cell membrane of a neurone that takes place when a nerve impulse is transmitted
What is the Gamma-aminobutyric acid (GABA) neurotransmitter?
- calming
- low levels of anxiety/ epilepsy
What is dopamine?
A neurotransmitter that plays a role in pleasure feelings, motivation, and addiction
What is Serotonin?
A neurotransmitter that controls mood and happiness. It also works with melatonin to regulate sleep-wake cycle
What is noradrenaline?
A neurotransmitter that regulates arousal and attention. Prepares for flight, freeze or flight
What is acetylcholine?
A neurotransmitter that regulates memory, thinking and learning. Damage to area in brain that produces this can lead to Alzemhiers
What is a receptor?
If a certain chemical neurotransmitter fits like a key, the message will be passed on
How do synapse work? (5)
- neurones communicate with the neural network via the synaptic gap
- synaptic transmission occurs when a resting neurone is sufficiently stimulated to depolarise which creates an electrical impulse (axon potential) to travel from the body to the axon to the axon terminal buttons
- Axon potential tiggers the vesticles in the axon terminal buttons of the pre-synaptic neurone which releases neurotransmitters to diffuse into the synaptic gap
- neurotransmitters bind with specific receptors in the dendrite of the post-synaptic neurone and are taken in
- chemical signal carried in these neurotransmitters may then trigger an action potential in the post synaptic neurone if strong enough.
What is a drug?
Any chemical you take that affects the way your body works (must be able to go to the brain)
How do drugs work?
They copy or block the effects of naturally occurring chemicals in the brain and change messages from brain to the rest of the body
What makes drugs addictive? (5)
- when you’re dependant on it
- unpleasant withdrawal symptoms
- crave drugs even when withdrawal symptoms are gone
- drugs activate the brains “reward system” by increasing the release of chemical dopamine in the neurones in the brain
- dopamine is released after pleasurable experiences, so dopamine of artificial release is more craving
What neurotransmitters does cannabis affect?
Cannabis affects neurones releasing acetylcholine, dopamine and noradrenaline, therefore changing our interpretations of the world, our mood, and behaviour
What is LSD and what does it do in the brain?
- LSD is a combination of an artificial acid and a natural molecule found in fungus.
- LSD mimics serotonin release in the brain to give the sensation of “tripping”
What is a stimulant?
Drugs that make you feel more alert (harmful and addictive)
E.g. nicotine, cocaine and amphetamine
What does nicotine do in the brain?
- inhaled and absorbed through the lungs and reaches brain in 7 seconds.
- mimics acetylcholine by docking with the nicotinic receptors which excited the neurone and triggers the release of dopamine.
What is cocaine and what does it do in the brain?
- cocaine is found in the leaves of the shrub Erythrooxlon coca
- it blocks the binding site on pre-synaptic neurone to prevent re-uptake of dopamine so more dopamine is uptaken through receptors
- this exaggerates changes cause by noradrenaline and dopamine which increases alertness and euphoria.
What is a sedative?
Drugs that calm you down used to reduce anxiety but can kill you
E.g. alcohol, Valium, Xanax
What is serotonin’s affect on aggression?
- reducing serotonin levels = increasing aggression
- increasing serotonin levels = reducing aggression
What is 5-HIAA?
A chemical produced by the reuptake of serotonin
- high levels of 5-HIAA = high levels of serotonin = low levels of aggression (negative correlation)
Link to dopamine and aggression?
High levels of dopamine = high levels of aggression
What is brain plasticity?
The brain adapts to what we experience.
What is testosterone?
- hormone linked to aggression
- produced in spurts, levels can rise suddenly
- males produce more than women
What is castration
The removal of testes to reduce testosterone
Wagner (1979)
- took a baseline measurement of testosterone in mice
- castrated mice and found aggression levels had dropped
- then injected mice with testosterone and aggression levels rose back up to pre-castrated levels
Vom Saal (1983)
Female rats who had developed closest to males in the uterus were the most aggressive females in the little due to prenatal exposure to testosterone
Dabbs (1995)
- measured testosterone in saliva of 692 adult male prisoners
- found higher level of testosterone in rapists and violent offenders than less offensive crimes like burglary
- those with higher levels of testosterone were rated higher amongst the other prisoners for being “tough”
Dabbs (1996)
- research 12 fraternity houses
- those with highest testosterone were described as “boisterous and macho”
Mazur and Booth (1998)
Men with higher level of testosterone are more likely to be…
- divorced
- arrested
- incur bad debts
- use weapons in fights
Van Goozen (1997)
- natural experiment on transgender sex change patients
- males receiving testosterone suppressants became less aggressive
- females receiving testosterone became more aggressive
