Week 2 Notes
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This 7 page Class Notes was uploaded by Emilie Vainer on Sunday August 30, 2015. The Class Notes belongs to PSYC 4130 at University of Georgia taught by James Stringham in Summer 2015. Since its upload, it has received 37 views. For similar materials see Physio Comp Psych in Psychlogy at University of Georgia.
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Date Created: 08/30/15
Biological Physiological Psychology What Where Who When How and Why Biological psychology The study of the in uence of biological and physiological systems on behavior Behavior Anything an organism does that involves action and response to stimulation What produces behavior The mind The brain Are they different They seem to be Aristotle 384 322 BCE the mind resides in the heartbrain serves to cool the blood Later said brain produces human actions Ancient Egyptians heart is where the mind is when they embalmed a person the heart was preserved and the brain discarded Before Aristotle Plato Aristotle s teacher 427 347 BCE reasoned that the mind resides in the brain The sphere is the perfect geometrical shape so the mind must be located in the spherical head Hippocrates 460 377 BCE said brain is the organ of the mind Galen 130 200 AD propelled Hippocrates theory forward Dualism the idea that both body brain and mind exist as separate entities Rene Descartes 1596 1650 a dualist contended that movements of the pineal gland ultimately produced the mind Leibniz 16461715 a dualist mind and body brain don t interact they only appear to interactlike two perfectly synchronized clocks Thomas Hobbes 1588 1679 epiphenomenalism The activities of the brain produce the mind but the activities of the mind are irrelevant to the brain The noise of a vacuum cleaner is an epiphenomenon and totally unnecessary for sucking up dirt and hair What do you think a modern neuroscientist says about the mind and the brain Modern neuroscience subscribes to monism where the mind and brain are considered one and the same Could it be possible that the roughly 3 1b glob of jelly between your ears is the mind The brain has no moving parts On visual inspection it is just a lump of grayish tissue No indication that there are many billions of smaller units called neurons that make up the brain Camillo Golgi 1870 developed a staining technique that yielded good contrast between the different types of tissues in the brain Place a thin slice of brain into silver nitrate and some of the individual cells can be seen under a microscope Only about 1 of the cells took up the stain which actually made visualization of the cells easier Santiago Ramon y Cajal 1878 Spanish physiologist used the Golgi staining method in newborn animals brain tissue less dense with neural processes to discover that those cells that took up the stain were individual units He also discovered other types of neurons receptors which are like other neurons but with specialized parts for detecting information from the environment Also discovered the synapse a tiny gap found between neuron units Charles Sherrington 1857 1952 tested spinal re exes in dogs which required the function of three neurons 1 a sensory neuron 2 a motor neuron and 3 a neuron that connected the two called an interneuron He measured the time it took for electrical pulse to travel down a single neuron Then he measured the time it took for an electrical pulse to travel through the three neurons involved in a spinal re ex It took longer than the time of the single neuron multiplied by 3 This suggested that electrical current was not the source of communication between neurons Must be something else Otto Loewi 1863 1961 despite prevailing wisdom of the day says neurons don t communicate with electricity I believe it s chemicalsquot Conducts an amazing experiment with frog hearts the idea for his key experiment came to him in his sleep Loewi dissected out of frogs two beating hearts one with the vagus nerve which slows heart rate attached the other heart without the vagus nerve Both hearts were bathed in a saline solution Loewi electrically stimulated the vagus nerve of the first heart which caused it to beat slower How vagus parasympathetic slow down Then he took some of the liquid bathing the first heart and added it to the other heart s bathing solution The application of the liquid made the second heart also beat slower proving that some soluble chemical released by the vagus nerve was controlling the heart rate Before Loewi39s experiments it was unclear whether signaling across the synapse was bioelectrical or chemical Loewi39s famous experiment published in 1921 largely answered this question He called the unknown chemical Vagusstoff It was later found that this chemical corresponded to acetylcholine we ll learn plenty about acetylcholine later Broca s area Paul Broca 1860 s Frontal lobe structure in left hemisphere in roughly 90 of people for 10 it s in the right hemisphere responsible for speech production Near motor strip of frontal lobe Wernicke s area Carl Wernicke 1874 Temporal lobe structure again left hemisphere in most responsible for speech comprehension Broca s aphasia non uent aphasia Wernicke s aphasia uent aphasia Wilder Penfield 1935 Famous brain surgeon responsible for modernday formulation of localization of functionquot Electrophysiological studies EEG electroencephalograph1930 s many electrodes placed on patient s scalp often used in sleep research 4 Animal Studies Animal Models Lesioning a small part of an animal brain is removed the effects of the lesion are then studied Ablation studies a large portion of the brain like an entire lobe of the cortex is removed 5 Modern Techniques a CAT scan Computerized Axial Tomography Xrays pass through the patient s head a computer creates an image of the brain Abnormal tissue eg tumors tend to show up darker in the picture Decent resolution September 2014 24year old woman discovered to have been born without a cerebellum responsible for motor coordination riding a bike posture balance motor learning and speech She was nearly normal in most ways but had serious issues with motor function didn t speak until she was 6 and couldn t walk until 7 Also had never been able to play and jump like normal kids Gave birth to a neurologically normal daughter b MRI Magnetic Resonance Imaging Uses strong magnetic fields radio frequency pulses and computers to compose the image The resolution of the picture is much greater than the CAT scan Can be threedimensional c fMRI functional MRI Allows realtime imaging of brain function with MRI resolution Very cool research tool d PET scan Positron Emission Tomography A small amount of radioactive material is injected into the bloodstream The material binds to glucose which the brain uses together with oxygen to function The PET scan detects where the radioactive material goes Autoradiography inject a radioactive chemical into the bloodstream of an animal wait for the chemical to ow through the nervous system eg brain sacrifice the animal thinly slice the brain and place it onto xray film Can see where the specific chemical goes in the brain Right postmortem human brain radioactively tagged serotonin found to selectively bind in neocortex hippocampus and raphe nucleus where it is synthesized in the brain Microdialysis chemical analysis performed on a living animal A very small tube cannula is inserted into neural tissue in a specific location in the brain Neurochemicals diffuse into the tube can be identified with a chromatograph which detects the spectral signature of specific chemicals The image at right shows a rat with a dialysis probe chronically implanted into the nucleus accumbens Dopamine levels were found to be elevated in this area when rats were anticipating or engaging in sexual behavior Exploring the Nervous System Importance of the Nervous System We are designed to detect stimuli in our environment process it and then react or not Input 9 output Constantly Four primary functions of the nervous system Detect stimuli in the environment Determine the significance of the environmental stimuli Make a decision based on the stimuli Execute a response The Organization of the Nervous System The vertebrate nervous system consists of two branches 1 peripheral and 2 central The peripheral nervous system PNS 1 Detects environmental eg pressure on your finger and internal visceral sensory information 2 sends it to the brain central nervous system where the information is processed and then 3 transmits the brain s quotdecisionquot to muscles glands and or organs executes a response The PNS contains two divisions 1 The somatic nervous system consists of both the sensory receptors and the nerves that activate the skeletal muscles We are generally aware of somatic nervous system function 2 The autonomic nervous system the nerves that regulate the functioning of the internal organs We are generally unaware of autonomic nervous system function Visceral sensory function Heart rate respiration digestive function etc The central nervous system Brain Spinal cord Can respond directly to a spinal re ex Or simply acts as a quotconduitquot for sensory or motor information to and from brain The brain is the most complex structure in the known universe 100 billion neurons in average adult human brain 302 neurons in entire Caenorhabditis elegan s nervous system The minimum possible number of connections between the neurons in your brain is 100 trillion Minimum Anatomical Directions and Perspectives Anterior toward the front Posterior toward the rear Ventral toward the belly Dorsal toward the back Rostral toward the nose Caudal toward the tail Medial toward the midline Lateral away from the midline Superior above a structure Inferior below a structure Horizontal section A section of a structure as viewed from above Sagittal section A section of a structure produced by a plane that cuts the structure into left and right parts Coronal section A section of a structure as viewed from the front What is the nervous system made of Neurons the cells that perform informationprocessing and communication function of the nervous system Neurons can communicate with other neurons with blood vessels with muscles or with glands AND probably glial cells see below The average human nervous system contains 100 billion neurons Glial cells cells that have a support function About 110th the size of neurons but 10 times as numerous So neurons and glia occupy roughly the same volume in the nervous system Basic types of neurons Sensory a specialized neuron that detects information from inside the body or from the outside world Motor a specialized neuron that carries messages from the CNS to muscles Interneuron a neuron that connects a sensory and a motor neuron or communicates with other neurons Found in the brain and spinal cord Re exes Types of glial cells Astrocytes provide physical support for a neuron transport nutrients in and waste products out Also regulate blood ow and guide neural development Only in brain Oligodendrocytes Myelinate certain neurons in the CNS Schwann cells Myelinate certain neurons in the PNS Microglia remove the debris of dead neurons Neurons Neurons are responsible for nearly all communication in the brain and body There are roughly 100 BILLION neurons in the adult human brain Our brains undergo a quotpruningquot of sorts as the neural pathways developthe brain actually becomes more efficient this way Commensurate with the pruning is a focal dense wiring of neural networks Areas that are stimulated by experience eg vision start getting wired upquot Anatomy of a Neuron Cell body or soma contains the nucleus and other metabolic mechanisms needed to keep the cell alive Dendrites widely branching structures that receive transmissions from other neurons Axon The axon is a single long thin straight fiber with branches near its tip Myelin sheath The myelin sheath is an insulating material found wrapped around the axon This helps to speed transmission just like insulation on an electrical wire i 100 meters sec in myelinated axon ii 1 meter sec in unmyelinated axon Nodes of Ranvier gaps between quotchunksquot of myelin This is where the action potential is regenerated Terminal Buttons the feet at the end of the axon this is where neurotransmitter is released and travels across the Synapse the specialized junction or gap between two neurons a motor neuron it communicates with muscle tissue at the myoneural junction Basic Sensory Neuron This could be a touch receptor in your fingertip When it gets compressed it quotfiresquot a signal and relays it to the brain via other neurons Glial neuroglial cellsliterally nerve gluequot Additional details functions of glia Astrocytes Largest glial cell In addition to their previously listed functions they also cover the blood vessels that form the bloodbrain barrier BBB prevents most compounds from entering the brain from the blood Astrocytes are involved in the development and maintenance of the BBB not the barrier function Evidence to suggest that astrocytes integrate neuronal messages and release neurotransmitters that a ect the sensitivity of synapses Schwann cells appear to be involved in axonal regeneration after injury PNS Oligodendrocytes appear to inhibit regeneration via growth inhibitory proteins CNS The Peripheral Nervous System Quick review Broken into two branches 1 2 1 2 Somatic Nervous System Autonomic Nervous System The somatic nervous system allows us to interact with our environment Afferent coming toward neurons bring information from sensory receptors to the CNS Efferent going away from neurons take messages from the CNS to the skeletal muscles The somatic nervous system has two main types of nerves Spinal nerves send messages to and from the brain through the spinal cord Cranial nerves directly link the sensory receptors of the head to the brain and the brain to certain muscles 4 of 12 cranial nerves serve both sensory and motor functions Dermatomes areas of skin innervated by the spinal nerves from a particular segment of the spinal cord see right Sensory fibers enter the spinal cord from the dorsal side back They are organized by location of the body and bundled together They enter the spinal cord through a dorsal nerve rootquot The skin area supplied by nerve fibers originating from a single dorsal nerve root is the dermatome Shingles Herpes Zoster When a dorsal nerve root is infected by the herpes zoster virus same as chicken pox the corresponding dermatome becomes affected The Autonomic Nervous System Contains efferent neurons that control glandular activity and internal organ functioning Two divisions 1 sympathetic nervous system SNS and 2 Parasympathetic nervous system PRNS The SNS activated by conditions that promote arousal particularly in situations involving emotional reactions to stressors Stimulation of the SNS prepares an organism to respond to challenging or dangerous conditions Fight or ightquot response The PRNS activated by conditions of recovery or the termination of stressors allows the organism to replenish energydepleted stores The SNS and PRNS are generally antagonistic and serve to balance the overall state of arousal SNS rapid activation due to short preganglionic axonsmass effect on organ activation PRNS relatively slow activation due to long preganglionic axonsspecific organs affected Ganglion a nerve cell cluster or a group of nerve cell bodies
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