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Neurones and Synaptic Transmission - Coggle Diagram
Neurones and Synaptic Transmission
AO3
strength of human brain scanning
can apply to other humans more easily than with animal brain scans
high scientific credibility
multiple people can check results - high reliability
Allen and Stevens (1994)
less than half the neurotransmitters in synapses in the hippocampus arrived from presynaptic membrane
synaptic transmission is not straightforward, may be less involved in behaviour than first thought?
PET scanning by Jovanovic
investigated serotonin in women
low levels associated with depression
found differences in synaptic receptors related to serotonin in women with premenstrual dysphoric disorder
problem with evidence for neurotransmitters
most evidence comes from animal lesion studies
low generalisability/credibility/ecological/population validity as neurotransmitters may behave differently in animals and humans
central nervous system
made up of
brain
and
spinal cord
function:
nerves send info via CNS
brain processes info
sends message to body through spinal cord using neurones
neurotransmitters
chemicals released from neurones, diffuse across synapses and bind to receptors
examples
serotonin
:
linked to happiness & good mood
regulates sleep/wake cycle
low levels linked to depression
high levels linked to anxiety
GABA
:
inhibitor - blocks messages
calms nerves
produces feelings of relaxation
low levels linked with anxiety & epilepsy
dopamine
:
linked to pleasure & addiction
released from reward centre of brain
glutamate
:
controls levels of dopamine
linked to schizophrenia
inhibitory neurotransmitters
:
cause fewer Na+ ions to enter next neurone, stops message
excitatory neurotransmitters
:
cause Na+ ion to enter next neurone, message continues
synaptic transmission
impulse (Na+)
ions travel down the
axon
to the axon terminal
vesicles
containing the neurotransmitters fuse to the
presynaptic membrane
presynaptic membrane
releases neurotransmitters
across the synaptic gap
neurotransmitters bind to
receptors
on the
postsynaptic membrane
this starts an impulse down the next neurone
neurotransmitters are either
broken down
by
enzymes
or taken back up into the presynaptic membranes by
reuptake ports
broken down by enzymes
:
dopamine
acetylcholine
reuptaken
:
serotonin
dopamine