There are various methods for gaining scientific knowledge Experimental knowledge is crucial to a causal understanding Even carefully designed experiments yield results open to multiple Davidson study 2003 continued o Conclusions interpretations o Important in the experimental process How do we refine Observe ask Explore correlations Examine processes we can t see Manipulate variables experiment Examine results What are other explanations Introduction to Biological Psychology The Nervous System and Neurotransmitter Processes Overview o How does the nervous system operate o Basic neuron structure physiology o How do neurotransmitters influence emotion thought behavior o Specific neurotransmitters their neuronal psychological functions o How are neural messages integrated into communication systems o How do different parts of the nervous system interact What is a neuron o A building block of the nervous system o Communication cells they collect integrate transmit electrochemical info o Dendrites collect info they look like branches o Cell body makes sense of the info received by the dendrites o Axons Transmit info at the synapse o Vesicles release neurotransmitters across the synapse o Myelin sheath made up of glial cells brings nourishment serves as protection for axons like an electrical cord the insulation allows for smooth transmission Different types of neurons o Sensory afferent neurons pick up info from the environment from sensory organs send it to the brain e g touch pain heat o Motor efferent neurons affect movement signals from the spinal cord to muscles the periphery e g walking sends information from taking a step to the brain which sends signals to the muscles to contract to keep walking o Interneurons there are billions way more than other types of neurons they communicate between neurons Myelin sheath o Made of glial cells insulation for axons speeds neural transmission o There are gaps in the sheath which allow saltatory conduction o Saltatory conduction when action potentials jump across the nodes of ranvier o Nodes of ranvier the space between 2 myelin sheaths on an axon where depolarization action potentials occur Glial cells protective they can increase in number as the brain is used Demyelinating disease o E g multiple sclerosis o When the myelin sheath deteriorates o This causes lesions scarring in the brain nerve pain o Transmission from one neuron to the next is slowed o There are problems w coordination smooth movements Action potentials cause neuronal communication o Depolarization or hyperpolarization is required for neurons to communicate At rest the neuron is more negative on the inside than on the outside it is o Changes in electrical potential lead to action o Resting membrane potential o Depolarization negatively charged The neuron receives a signal The gates open in the cell membrane The potential changes A neuron receives a signal The gates in the cell membrane open Sodium ions Na rush in The inside becomes slightly more positive This causes action Action potentials are an all or nothing event o Hyperpolarization Neurons are less likely to fire Sodium channels are less likely to allow sodium into the neuron This is known as resting potential The inside is more negative than the outside Mirror neurons o They are found in the frontal and parietal lobes o They fire when you observe someone engaging in behavior even though you yourself may not be engaging in the same behavior o E g when you are watching soccer the neurons are firing even though you aren t playing o You recognize another person s goals intentions o Autism may be the result of mirror neuron dysfunction Neurotransmitters psychological functions o Agonist facilitates neurotransmitters it enhances the effects E g depression is the result of low levels of serotonin Serotonin is released but not enough of it more needs to be available Serotonin selective reuptake inhibitor SSRI can help it slows the process of the reuptake of serotonin It is the most common antidepressant b c there are few side effects MAO inhibitor is another type of antidepressant that inhibits the breakdown of serotonin in the terminal button so there is more serotonin to be released o Antagonist inhibits neurotransmitter effects blocks receptor cells o Research on Acethylcholine Ach A neurotransmitter that causes muscle contraction regulates attention sleep also important for memory Shortage causes memory deficits Might be able to combat Alzheimer s with it unless the brain is already Joseph Martinez conducted an experiment on the causal relationship between damaged Ach memory He injected mice with Scopolamine or a saline after letting them learn a maze and observed if they remembered where the food was located Operational IV scopolamine the control was a saline o Scopolamine blocks Ach it is an antagonist o The corresponding agonist is physostygmine which facilitates learning enhances memory Operational DV time to finding the food in the maze o The theoretical DV was memory Result scopolamine inhibited the mice from remembering where the food was located so they took longer to find it than the control group Overview onew way to organize categorize neurotransmitters o Acetylcholine affects motor control mental processes Links smooth motor muscle control neurons Curare Ach antagonist which causes temporary muscle paralysis is deathly b c it stops the heart lungs from functioning Causes muscle contraction regulates attention memory sleep A shortage causes memory deficits sometimes delusions Excess causes spasms o Mononoamines single amino acids Involved in arousal motivation Epinephrine adrenaline in the bloodstream norephinephrine a stimulant serotonin dopamine