Neurons and synaptic transmission
Synaptic transmission – impulses generated at axon hillock, Neurotransmitters –
chemical message at terminal button, neurons can pass across the Acetylcholine – Memory and
synaptic gap this is presynaptic transmission, other side is post learning
synaptic. When action potential reaches axon terminal, calcium Noradrenaline – Gives attention,
channels open, flooding the terminal button with calcium ions. prepares for fight or flight
Vesicles containing the neurotransmitter substance will then be Dopamine – Pleasure feelings
released. Receptors bind to specific neurotransmitter, any neuron and addiction
left in synaptic cleft = reuptake Serotonin – Happiness and good
mood, low levels cause
Action potential – method where nerve impulse travel down axon depression
to stimulate release of neurotransmitters. Neurons have a resting
membrane potential of about –70mV. When neuron receives a
message, it can be excitatory postsynaptic potential, meaning that
it will increase the charge of the neuron (towards 0), or be an
inhibitory postsynaptic potential, decreasing the charge (further
away from 0). When it has received enough excitatory messages,
then an action potential is triggered.
1. When the neuron is at rest, the inside is negatively charged
relative to the outside
2. When the neuron is stimulated, positively charged particles enter
– the action potential is initiated
3. Some positively charged particles are pushed outside the neuron,
, Recreational drugs and aggression
The brain had a reward pathway which causes a pleasant and rewarding feeling. This encourages the
behaviour to be repeated this is a key component to learning as if something causes pleasure, then we
want more of the pleasure
The brain reacts to a sudden increase in a neurotransmitters, so it will down regulate its own
production, this means that when the drugs wears off, the person will have less of the neurotransmitter
than they normally would. This results in an unpleasurable experience, so they may take more of the
drug
Examples include:
- Cocaine – increase activity in dopamine pathway by blocking reuptake of dopamine
- Nicotine – increases amount of dopamine by blocking the enzyme that breaks it down
- Alcohol – inhibits neural transmission by increasing action of GABA (reduces anxiety and promotes
relaxation)
Strengths:
- Olds and Milner rats could give brains pleasurable electric shocks by pressing lever, rats would press
lever over and over, and would ignores likes of food
- Face validity as observations of drug users tend to match what neurobiology of drugs predicts
- Application to drug replacement therapy, which gives user substitute for drug in a controlled way
Weaknesses:
- Generalising from animal research is problematic
Synaptic transmission – impulses generated at axon hillock, Neurotransmitters –
chemical message at terminal button, neurons can pass across the Acetylcholine – Memory and
synaptic gap this is presynaptic transmission, other side is post learning
synaptic. When action potential reaches axon terminal, calcium Noradrenaline – Gives attention,
channels open, flooding the terminal button with calcium ions. prepares for fight or flight
Vesicles containing the neurotransmitter substance will then be Dopamine – Pleasure feelings
released. Receptors bind to specific neurotransmitter, any neuron and addiction
left in synaptic cleft = reuptake Serotonin – Happiness and good
mood, low levels cause
Action potential – method where nerve impulse travel down axon depression
to stimulate release of neurotransmitters. Neurons have a resting
membrane potential of about –70mV. When neuron receives a
message, it can be excitatory postsynaptic potential, meaning that
it will increase the charge of the neuron (towards 0), or be an
inhibitory postsynaptic potential, decreasing the charge (further
away from 0). When it has received enough excitatory messages,
then an action potential is triggered.
1. When the neuron is at rest, the inside is negatively charged
relative to the outside
2. When the neuron is stimulated, positively charged particles enter
– the action potential is initiated
3. Some positively charged particles are pushed outside the neuron,
, Recreational drugs and aggression
The brain had a reward pathway which causes a pleasant and rewarding feeling. This encourages the
behaviour to be repeated this is a key component to learning as if something causes pleasure, then we
want more of the pleasure
The brain reacts to a sudden increase in a neurotransmitters, so it will down regulate its own
production, this means that when the drugs wears off, the person will have less of the neurotransmitter
than they normally would. This results in an unpleasurable experience, so they may take more of the
drug
Examples include:
- Cocaine – increase activity in dopamine pathway by blocking reuptake of dopamine
- Nicotine – increases amount of dopamine by blocking the enzyme that breaks it down
- Alcohol – inhibits neural transmission by increasing action of GABA (reduces anxiety and promotes
relaxation)
Strengths:
- Olds and Milner rats could give brains pleasurable electric shocks by pressing lever, rats would press
lever over and over, and would ignores likes of food
- Face validity as observations of drug users tend to match what neurobiology of drugs predicts
- Application to drug replacement therapy, which gives user substitute for drug in a controlled way
Weaknesses:
- Generalising from animal research is problematic
