drugs/NTs

• effect of drugs

  . we have the mesocorticolimbic pathway - causes to feel rewarding feelings and encourages repeating behaviours, operates on dopamine - drugs hijack the system

  . stimulants eg cocaine = increases NT activity by increasing dopamine in synaptic cleft by blocking their reuptake = prolonged effect of the NT on postsynaptic neuron

  . depressants eg alcohol = decreases NT activity, increase activity of GABA which binds to glutamate receptors, prevents glutamate binding = deceased effect of glutamate

  . Hallucinogens eg LSO = act on serotonin receptors, release more serotonin in different brain areas
• addiction withdrawal system

  1. drug taken = increases dopamine in reward pathway = feel good - brain reactions to increase of D and downregulates its own natural production of it
  2. drug effects wear off - person has less dopamine than normal = fells down and depressed = motivates them to take more
  3. person takes more to reproduce first feeling - repeated use = further downregulation of D production - brain adapts so now doesn't operate normally without the drug
  4. stop taking drug = lack of dopamine = depressed and low = withdrawal = keeps taking drug to avoid this - addiction
• neurotransmitters

  . are chemical messengers that act between neurons

  . can be excitatory on inhibitory depending on effect they have on neighboring NTs

  . serotonin = causes inhibition in postsynaptic neuron = makes neuron more negatively charged and less likely to fire

  . dopamine = causes excitation on postsynaptic neuron by increasing its positive charge = more likely to fire

  . summation = the adding together of signals - the firing of the postsynaptic neuron depends on the summation of the charges received