Components of the Nervous SystemComponents of the Nervous System

Glial cells (glia) Provide firmness and structure to the brain Get nutrients into the system Form myelin Create the blood-brain barrier Initially thought to be passive in comparison to “flashy” neurons Communicate with other glia & neurons New frontier: play a central role in addiction and mental health issues

Neurons Analyze and transmit information Four defined regions

Cell body

Dendrites

Axon Presynaptic terminals

Communicate through neurotransmitters

NeuronNeuron

Chemical Pathways: NeurotransmittersChemical Pathways: Neurotransmitters

7 Main neurotransmitters in the study of psychoactive drugs Dopamine Serotonin Norepinephrine GABA Endorphins Glutamate Acetylcholine

Chemical Pathways: Neurotransmitters

1. Dopamine Component of “reward” properties of drugs Mood & movement Attention & memory

2. Serotonin Mood & sleep Desire & impulse Stimulants & Hallucinogens

3. Norepinephrine Mood & movement Memory & sensory processing Stimulants

Chemical Pathways: NeurotransmittersChemical Pathways: Neurotransmitters

4. GABA Sedation, drowsiness and relaxation Depressants

5. Endorphins Pain relief & sedation Rate of bodily functions Opioids

6. Glutamate Learning, cognition & memory Hallucinogens & alcohol

7. Acetylcholine Involved in diverse processes: memory, attention & mood Nicotine

Impact on Neurotransmission

Psychoactive substances can impact neurotransmitters in both the intoxication and withdrawal process

Many ways psychoactive drugs can impact neurotransmission - 3 common ways: Increase neurotransmitter activity

Agonist

Reduce neurotransmitter activity Antagonist

Blocking reuptake of neurotransmitter Reuptake inhibitors

Chemical Theories of BehaviorChemical Theories of Behavior

Variations in behavior explained through changes in brain chemistry Historical and cultural perspectives Monoamine theory of mood Issue of experimental support

Brain imaging techniques Types Reactions