Neurotransmission Using one or more examples, explain effects of neurotransmission on human behavior. Studies • Martinez & Kesner • Fisher Terms • Neuron • Action Potential (and neural anatomy) • Neurotransmitters • ACH • Dopamine • Drugs (agonist, antagonists and reuptake inhibitors) • Using one or more examples, explain effects of neurotransmission on human behavior. What is a Neuron? • A nerve cell. • It is estimated we have about 100 billion of them in our brain. They essentially have one purpose only…. • To communicate to each other But neurons NEVER touch…. • They are shomer nagia (and will never ever marry) • There is always a space in between them called the synapse. • The neurons essentially throw chemicals back and forth across the synapse. • Communication is a chemical process, where one neuron sends out chemicals called neurotransmitters. • The next neuron will pick it up with their dendrites and may or may not keep the message going. • Neurotransmitters are stored in vesicles and are sent to the edge of the button and released into the synapse. • If it fits, it can bind with the dendrites on the next neuron. If enough neurotransmitter binds, it will “fire” and send neurotransmitter across next synapse. • Any unused neurotransmitter will be sucked back into the neuron. This process is called reuptake. Then the neurotransmitter can be used again. Types of Neurotransmitters Acetylcholine (ACH) • Involved in movement and memory. • Too much causes convulsions (black widow venom). • Too little can cause paralysis (curare) . Martinez & Kesner (1991) • Aim: Determine role of ACH on memory • Procedure: 3 groups of rats trained to go through maze – received food • 1st – blocked ACH • 2nd – blocked “clean-up” of ACH • 3rd – no injections • Results: Less ACH more errors More ACH fewer errors • Conclusion: ACH played a key role in creating a memory of the maze Evaluation of the Study • Strengths: Research design & application experimental method & control group helped researchers see cause/effect relationship b/w ACH & memory • Limitations: Research may not apply to humans Dopamine • Involved in motor movement, alertness and memory. • Too little can cause Parkinson’s disease • L-dopa is the drug for Parkinsons…what do you think it does? Dopamine • Too much dopamine has been linked to schizophrenia. • Anti-psychotic medication such as chlorpromazine is used for schizophrenia…what do you think it does? Cocaine and Dopamine • A stimulant that brings about intense feelings of pleasure and sometimes faster cognitive ability. • How do you think it works? Fisher (2004) • Being “in love” is similar to being “addicted”. • Took 40 young people in love. • 20 with love returned, 20 with love rejected. • Showed them pictures of sweetheart, then just and acquaintance off and on for 30 seconds each for 12 minutes. • Gave them fMRI while showing pictures. Fisher (2004) Results • Increased blood flow where areas of the brain flood dopamine for those where love reciprocated. • Similar brain activity as if you were on cocaine. • Decreased in those rejected. • Love seems to not be an emotion but a drive to seek pleasure. Serotonin • Involved in mood control. • Prozac given to people who are depressed…what do you think it does? Drugs • a substance which may have medicinal, intoxicating, performance enhancing or other effects when taken or put into a human body. • In reality…they just manipulate neurotransmitters. • Three ways Agonists • Some drugs mimic a neurotransmitter thus encourage its production. • Examples are opiates (morphine, Oxycodone) Antagonist • Some drugs block the production of neurotransmitter. • Dopamine receptor antagonists are used for some diseases such as Schizophrenia, Bipolar disorder, nausea and vo miting. It can also control the symptoms of hyper sexuality and increased orgasmic activity. Reuptake Inhibitor • Some drugs prevent the reuptake of neurotransmitters by the axon terminal. • SSRI - Selective Serotonin Reuptake Inhibitors (Celexa, Paxil, Prozac or Zoloft) • Cocaine Stoned Mice Drugs • Our brain is protected by a layer of capillaries called the blood-brain barrier. • The drugs that are small enough to pass through are called psychoactive drugs. Drugs If a drug is used often, a tolerance is created for the drug. Thus you need more of the drug to feel the same effect. If you stop using a drug you can develop withdrawal symptoms. Stimulants • Speed up body processes. • More powerful ones (like cocaine) give people feelings of invincibility. Depressants • Slows down body processes. • Alcohol • Anxiolytics (barbiturates and tranquilizers) Alcohol • More than 86 billion dollars are spent annually on alcoholic beverages. • Alcohol is involved in 60% of ALL crimes. • Alcohol is involved in over 70% of sexually related crimes. • Is it worth the cost? Hallucinogens • Psychedelics • Causes changes in perceptions of reality • LSD, peyote, psilocybin mushrooms and marijuana. • Reverse tolerance or synergistic effect Opiates • Has depressive and hallucinogenic qualities. • Agonist for endorphins and dopamine. • Derived from poppy plant. • Morphine, heroin, methadone and codeine. • All these drugs cross the placental barrier….teratogens.