Psychology 1101 Notes: Week 2
Psychology 1101 Notes: Week 2 Psyc 1101
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This 6 page Class Notes was uploaded by Michelle H. on Saturday August 27, 2016. The Class Notes belongs to Psyc 1101 at University of Georgia taught by Kara A. Dyckman in Fall 2016. Since its upload, it has received 5 views. For similar materials see Elementary Psycology in Psychology at University of Georgia.
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Date Created: 08/27/16
Chapter 2 A: General Overview Neuroscience The study of the brain and the nervous system Biological Psychology How the brain and the nervous system influence our behavior Brain: Orchestrates all behavior in the body. ● Composed of two hemispheres: the right and the left ● Brain weighs about 3 lbs. ● Made up of white matter and grey matter ○ White matter is mainly made up of axons ○ Grey matter is mainly made up of cell bodies Cerebrospinal Fluid: Cushions your brain from impacting the inside of the skull and prevents the brain from collapsing. ○ Concussions are caused when the impact is too severe and brain hits the skull ○ Generally has two points of impact at the front and back Neurons: Specialized cells that transmit nerve impulses through the brain. ● 86 to 100 billion neurons within the brain ● Communication between neurons causes everything that happens in the body B: Methods of Studying the Brain Phrenology: Determination of one’s personality by feeling bumps on the skull ● Created by Franz Joseph Gall (17571828) ● Has since been discredited and is considered a pseudoscience ● First time people considered parts of brain had impact on personality Ablation: Removing portions of the brain and observing how bodily functions are affected. ● Created by Pierre Flourens (1794 –1867) ● Usually done on rats or other animals in a controlled setting ● Case studies on individuals who have lost or damaged parts of their brain are also considered ablation CAT Scan: Stands for Computerized Axial Tomography ● A scanner uses Xrays to create multiple crosssections of the brain. ○ used to determine structural damage MRI:Stands for Magnetic Resonance Imaging ● Creates a powerful magnetic field that is able to pass through the brain and create crosssections of the brain ● Similar to CAT scans, but MRI scans are more detailed ● MRI gives a more accurate depiction of the brain, including soft tissue ○ Determines what areas of the brain are possibly damaged C: Methods of Watching Brain Functions ● EEG: Stands for Electroencephalogram ○ Electrodes are placed on the scalp and record the electrical activity taking place in the brain ○ Shows the intensity which certain parts of the brain respond to different stimuli ● PET: Stands for Positron Emission Tomography ○ A radioactive substance called a tracer is injected into the bloodstream of a subject ○ A computer tracks the location of the tracer while the subject is asked to perform certain tasks ○ The computer uses this information to create a 3D model of the brain that shows the amount of activity occurring in each part of the brain ● fMRI : Stands for functional MRI ○ Presents stimuli to participants while they are inside of MRI machine ○ Uses magnets to track changes in the blood oxygen level of participants ○ Shows the amount of activity in each part of the brain, similar to a PET scan. These new technologies allow for researchers to obtain realtime information about what the different parts of the brain are used for, allowing for new breakthroughs to be made much faster. D: Structure of a Neuron ● Cell Body: Contains the nucleus and all other mechanisms that keep the cell alive. ○ Also called soma ● Dendrites ○ Small,branch like fibers that come off the cell body ○ Each neuron contains many dendrites ○ Receives information from other neurons and deliver this information to the cell body. ■ Think of dendrites as little “arms” that extend out and “grab” information ● Axon: Tubelike structure that extends downwards from the cell body ○ Each neuron has only one axon. ○ Transmits information from the cell body to other neurons ● Myelin Sheaths: A fatlike substance that insulates the axon and speeds up the transfer of information between neurons. ■ The majority of neurons are myelinated, or contain myelin ■ However, some axons do not contain myelin ○ Without myelin, communication is slowed and the function controlled by the neuron is affected ■ Multiple Sclerosis is the result of the axon becoming demyelinated ■ The immune system of an individual with Multiple Sclerosis attacks the myelin, which causes it to break down ● Terminal Buds: Transmits messages to other neurons. ○ Located at the end of the axon. ● Synapse: The small space between the end of one neuron and the beginning of another neuron ○ Communication between neurons occurs in this location ○ Can also be called the synaptic cleft or the synaptic gap. ● Glia: Produces the myelin used by the myelin sheaths to protect the neurons. ○ Support cells to the neuron. ○ Glia is the “glue” of the nervous system: it provides cohesion and support for neurons ■ Neurons cannot store their own energy, glia provide this energy ○ Estimated 500 billion glia in the body Diagram of a Neuron Neuron Communication E: Process of Conveying Messages Within The Neuron Stage One: Rest ● Before a neuron “fires”, or transfers information, it is considered to be at rest. ● Channels within the neuron are closed, which prevents positive ions from entering. ● The voltage of the inside of the neuron is 70mV. This is called the resting potential. ● When the neuron is at its resting potential, the solution inside the cell is more negative than the outside of the cell. ○ Caused by the large amounts of salt on the outside of the neuron Stage Two: Action Potential ● Neuron receives a signal from either the environment or another neuron and is activated. ● When activated, some sodium channels are opened and positive ions begin to enter the neuron. ○ Sodium is positive, so it depolarizes the neuron, or makes it less negative ● Once neuron reaches a charge of 55mV, the action potential is triggered ● During the action potentials, all remaining sodium channels open until it reaches a charge of 30 mV ○ When the neuron is at a share of 30 mV, it fires. ● After the neuron reaches this charge, the sodium channels close and potassium channels open. ○ Potassium is negative, so the neuron is returned to rest. Stage 3: Action Potential Travels Length of Neuron ● When the action potential is reached in one segment of the axon, it causes a chain reaction down the remaining segments ○ These segments begin to also experience a voltage change ● The chain reaction allows for a message to be carried from the top of the axon to the terminal buds, allowing the message to be passed on to other neurons ○ The top of the axon is called t xon hillock. ● The only place this change in voltage can occur is in the break between the myelinated parts of axon ○ These breaks are called the ode of ranvier F: Conveying Messages Between Neurons ● Neurons use chemicals called neurotransmitters to communicate with each other ● When two neurons communicate with each other, it is called neurotransmission Process of Normal Neurotransmission ● The action potential travels down the axon, reaching the terminal buds. ● This triggers vesicles within the terminal buds to release neurotransmitters into the small space between the two neurons called the ynapse ○ Vesicles are small fluidfilled sacs within the neuron ● Neurotransmitters travel across the synapse to the receptor sites on the dendrite of the second neuron. ○ Receptor sites are the places on the receiving neuron that neurotransmitters attach to. ○ This causes positively charged ions to enter the second neuron and creates an action potential. ● After they bind to the receptor sites, any leftover neurotransmitters diffuse out of the synaptic gap or are reabsorbed into the first neuron. ○ When neurotransmitters are reabsorbed by the sending neuron, it is called reuptake ○ There are a variety of different neurotransmitters. If the neurotransmitter does not fit the receptor site of the receiving neuron, it is useless ■ Think of it like a key: if the neurotransmitter does not fit the lock (receptor site), it can’t be “opened" G: Effect on Behavior ● Axons send signals all throughout the body to cause bodily functions such as motion ● Sends signals all throughout body ● Affect how you think, glands, movement ● Drives everything that you do in ● Axons can be long or short ● Nerves are bundles of axons H: The Supporting Systems ● Brain needs supporting infrastructure to carry out directives and relay essential information from the outside Central Nervous System ● Spinal Cord: Transfers information from the brain to the peripheral nervous system (PNS) ○ Connects the brain to the rest of the body. ○ Reflex arc allows for motion to take place before signal reaches brain ○ Interneurons allow for movements to occur without the input of the brain ● Motor Neurons: Responsible for the movement of muscles ○ Motor neurons send axons down from the brain ○ Sensory neurons help us to receive information from the environment Brain Hemispheres ● Two hemispheres, the Right hemisphere and the left hemisphere ● Each hemisphere has 4 sections ● Contralaterally located, meaning the right hemisphere controls the left side,etc. ● The brain is plastic, meaning that it can alter its shape depending on what is needed. I: Lobes ● Frontal lobes: Controls higher level cognitive functions such as planning, personality, and planning ■ This part allows you to make decisions such as not going out partying the night before you have an exam ○ Humans have a much larger frontal lobe than most other mammals ○ Frontal lobe does not fully mature until the age of 2025 ● Parietal lobe: Processes sensory information such as touch and temperature as well as spatial information. ○ Spatial information allows you to understand your position in space and navigate your environment ● Optical lobe: Processes visual information ○ Humans rely mostly on their sense of vision, which explains the large area dedicated to processing this information ● Temporal lobe: Deals with hearing, comprehension, and language J: Specialized Areas ● Motor Cortex ○ Located in the back of the frontal lobe ○ When certain areas of the motor cortex correspond to different parts of the body ○ Stimulating these areas causes movement. ○ Body parts that require a lot of fine/complex movements have a larger area of the motor cortex dedicated to it ■ For example, your tongue has a much larger area than your knee ● Somatosensory Cortex ○ Located at the back of the parietal lobe touching the motor cortex ○ Processes nerve information from ○ It is possible to increase the amount of space dedicated to a certain body part ● Language Areas ○ There are two areas in your brain that deal with language formation, understanding, and acquisition ○ Broca’s area ■ Located in the frontal lobe ○ Wernicke’s area ■ Located in the temporal lobe ○ Both these areas are only located in the l eft hemisphere. ■ Stroke victims or those with brain damage in the left hemisphere may slur their words or have problems finding the proper words to use K: Operations to Correct Neurological Issues ● Hemispherectomies: Used to correct extreme problems with seizures (eg. 150 a day) ○ Exceptionally rare, often considered a last resort ● Colostomies: Known as a split brain operation ○ Done by cutting the corpus coliseum which severs the axons ■ Right and left hemispheres are disconnected and cannot communicate with each other ■ Allows for the two halves of the brain to act independently ○ Helps to control epilepsy
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