chemical messenger that travels neurone to neurone e.g dopamine
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How do neurotransmitter travel in the brain?
axon hillock=electrical impulse, goes to axon terminal=NT, terminal button open & fill with ca2+ ions, NT carried in vesicle, fuses with membrane and released from pre synaptic neurone
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What happens when the neurotransmitter is released into the synapse?
1) it is destroyed by enzymes, 2) there is re-uptake in the pre-synaptic neurone, 3)it is accepted by receptors on the post synaptic neurone
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What is the effect of cocaine on the brain?
works on the reward pathway and dopamine receptors. Blocks the binding site of the reuptake receptors so there is an excess of dopamine in the synapse= over stimulation at post synaptic neurone= desensitisation
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What is the effect of nicotine on the brain?
works on pleasure centre of the brain. Mimics the action of acetyl-choline by fitting to nicotinic reptors, causing an impulse in the neurone releasing dopamine. Over time the causes damage and decrease in dopamine receptors so more is required
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Describe CAT scanning
takes images of any part of the brain. Multiple beams are passed around the head, so detects areas of brain damage or positions of tumors. RISKS- exposure to radiation. Lusisns et al found a link between alcoholism and cerebral atrophy
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Describe PET scanning
form of nuclear medicine. Patient injected with radioactive substance FDG. Radioactive atoms attach to glucose which is used by the brain for energy, so measures brain activity. Used in Raine et al+
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Describe a fMRI scan
as neural activity increases, blood to brain increases to keep up with oxygen demand. Haemoglobin repels a magnetic field but when deoxygenated it follows it. Scanner detects the change creating a brain map
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What is good about brain scanning?
purely objective- not affected by researcher bias, easy to obtain inter-rater reliability, scientific so research is credible, high controls over extraneous variables so can establish cause and effect
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What was Li et al's aim?
to investigate the relationship between chronic heroin use and the effects on brain areas. Look for evidence of brain damage and functioning compared to a healthy control group
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Who were Li et al's participants?
14 heronin addicted males, mean age 35, from a rehab clinic in China, and a matcher pair controls
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What was Li et al's procedure?
pps went into fMRI scanner and focused attention for 5 mins on a target. This was immediately followed by a experimental condition (24 drug related pictures, 24 neutral picture) every 2 seconds in a random order. Between each picture- resting state
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What was Li's results?
in cue related task heroin users reported cravings and PCC more active than control. In resting state heroin users had stronger connectivity between PCC and bilateral insular than control. Positive correlation between reigons and length of abuse
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What was Li's conclusion?
1. cues trigger habitual reactions, 2) PCC is likely to have an important role in limbic system (explain why addicts are susceptible to relapse), 3. long term use= brain changes and more connectivity
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Other cards in this set
Card 2
Front
How do neurotransmitter travel in the brain?
Back
axon hillock=electrical impulse, goes to axon terminal=NT, terminal button open & fill with ca2+ ions, NT carried in vesicle, fuses with membrane and released from pre synaptic neurone
Card 3
Front
What happens when the neurotransmitter is released into the synapse?
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