Types of Neurons

• Sensory Neurons = AFFERENT NEURONS = Neurons that travel from the body to the brain.

• Motor Neurons = EFFERENT NEURONS = Neurons that travel from the brain to the body.

• Interneurons = connect the sensory and motor neurons located in the brain and spinal cord

• Mirror neurons

Most common neurotransmitters:

• Acetylcholine: muscle movement, attention, arousal and memory.

  • Deficiency of Acetylcholine causes Alzheimer’s disease: They cannot produce acetylcholine.

• Dopamine: voluntary movement, learning, memory, emotion.

  • Produces sensations of pleasure and reward

  • Excess of dopamine causes Schizophrenia

  • Deficiency of dopamine causes Parkinson’s: they cannot voluntarily move.

  • Drugs, shopping, eating: releases dopamine and causes your brain to want more. Sometimes your brain can’t keep up with producing dopamine and this leads to Parkinson’s in drug addicts.

• Serotonin: sleep, wakefulness, appetite, mood, aggression, impulsivity, and sensory perception.

  • Excess of serotonin causes bipolar disorder: impulsivity, staying awake for a long time and high energy.

  • Deficiency of serotonin causes depression and OCD’s

• Endorphins: pain relief and pleasure.

  • Opiate addiction lowers the natural levels of endorphins

• Norepinephrine: mobilize the brain and body for action. (fight or flight)

  • Deficiency of norepinephrine causes depression, anxiety and problems sleeping.

• GABA:  main inhibitory neurotransmitter in the brain

  • When GABA is present in the neuron, it prevents the neurons from firing.

  • Excess of GABA means not enough brain activity and can lead to hypersomnia

  • Deficiency of GABA causes anxiety and epilepsy

• Glutamate: main excitatory neurotransmitter in the brain involved in learning and memory

  • Excess of glutamate causes multiple sclerosis, too much Acetylcholine, high levels of anxiety, fear or insomnia.

  • Deficiency of glutamate causes psychosis, coma and death.

  • Release of glutamate after a stroke can cause brain damage

Agonists v.s. Antagonists:

• They are both drugs

• Agonists mimic neurotransmitters

• Antagonists block neurotransmitters