-
terminal branches & buttons
amplify signal
-
electrical signal
due to ions, along axon
-
chemical signal
due to neurotransmitters @ presynaptic terminal
-
How is AP fired?
- excitatory signal - inhibitory signal > threshold
- resting neuron = negative
- excitatory signal--> more positive
- inhibitory signal--> more negative
-
depolarization
more positive ions flow in
-
repolarization
channels close, return to negative state
-
reuptake of neurotransmitters
stops neurotransmitter action
-
AP vary in...
- frequency, not strength
- all-or-none firing
-
agonist
drug that enhances neurotransmitter action
-
antagonist
inhibit neurotransmitter action
-
sympathetic
fight or flight
-
-
plasticity
ability for brain to adapt as a result of injury
-
glutamate
- excitatory neurotransmitter aa
- aid learning & memory in hippocampus
-
epilepsy
high glutamate, low GABA--> over firing neurons
-
GABA
- inhibitory neurotransmitter aa
- reduce anxiety
-
serotonin
- system neurotransmitter produced in brainstem
- influences arousal, sleep, emotions, dreaming
-
depression
not enough serotonin
-
dopamine
- system neurotransmitter in basal ganglia & frontal lobe
- reward, motivation, voluntary movement
-
schizophrenia
too much dopamine
|
|
