PSB 2000 Intro to Brain and Behavior Lecture Notes Lectures 1 12 This set of notes is really long If you want to find notes for a specific date ex 1 27 or topic brain damage press Ctrl F on your keyboard Command F for Mac users and type in what you want to find It ll search the document for whatever specific word phrase you typed in and save you the time of scrolling through everything Behavior an action as a response Programmed behavior can help the organism live Instincts passed down thru the generations Genes can influence behavior but are not the main cause of it Genes should not be blamed for alcoholism for example DNA is used to create proteins which govern cell functions Cell functions can result in behavior but not all of them do Mendel s Laws of Inheritance 23 unique chromosomes 22 autosomal 1 sex 46 chromosome pairs 44 autosomal pairs 2 sex chromosomes XX or XY We have 2 copies of each chromosome one paternal and one maternal Allele for one gene the dif variations of it Homozygous 2 identical copies of gene both alleles for the same gene the same Heterozygous both alleles for the same gene different The order of DNA bases determines cell function DNA transcribed into RNA RNA translated into protein Presence of RNA or protein shows the gene is being expressed What can show mental traits are heritable Genetic mutants Family studies Twin studies Interfering variables may not be completely removed Traits may also be result of similar upbringing Twins separated at birth studies help refute similar upbringing explanation Identical twins 100 genetically identical one fertilized egg divided Fraternal twins 50 identical two eggs fertilized at same time If twins were brought up in dif families it may show genetic inheritance Must also consider environmental influences and positive feedback loop Genes can influence behavior slightly Reinforcement can change it a lot When studying identical twins one must also consider Being raised in the same family Being treated as two of the same person by parents Being in the same womb hormonal environment Their own behavioral feedback responses by others Some genes are sex limited by necessity Hormones are required for sex specific traits Genes don t cause behavior but instead influence it slightly Gene may give slightly greater propensity for getting addicted to drugs alcohol Genetic change change in brain Epigenetics gene expression caused by more than just genes They make the DNA more or less accessible Can cause flaws to result Can cause a second set or emergency encoding to activate Ex Good VS bad rat moms Some rats groom their babies a lot some only a little Took a low groomed baby and gave it to high groom mom Baby grew up to be high groom parent Trait caused by behavior Drug then administered to same rat grooming pattern messed up Ex Wartime effects on later generations People starved in WWII because Hitler stole their food Pregnant women gave birth to normal looking babies These babies grew up As adults they had higher rates of heart problems than other people groups Caused by nutrient deficiency or stress Cells divided into organelles Nucleus mitochondria etc Cell membrane function is crucial in nerve cells Central nervous system CNS Brain spinal cord retina in eyes Peripheral nervous system Cranial nerves enteric ns digestive Sympathetic ganglia SNS Parasympathetic ganglia PNS Nucleus stores expresses DNA Mitochondria produces energy as ATP Ribosomes protein RNA structure use RNA to build protein Endoplasmic reticulum ER Protein creation editing transport Smooth ER Rough ER covered in ribosomes Golgi body protein editing transport Cell membrane barrier protecting inner organelles from outside Cell types nerve muscle gland blood bone reproductive Nerve cells prob the most complex 15 000 20 000 out of 25 000 total genes expressed in CNS Cell membrane has phospholipid bilayer Lets water small neutral charged particles in thru channels Doesn t let large ones thru Transports larger stuff in thru other channels that require activation Positive or negative ions pass thru pumps Pos Na Ca2 K Neg Cl Nervous system has neurons and glial cells Neurons create receive translate electrical messages Many dif types of glial cells support neurons Neurons are the basic unit of the CNS Connected in huge networks Nucleus cluster of neurons This is a stereotypical neuron the motor neuron There are other types of neurons Neuron operation Dendrites receive signal from other neuron motor cortex etc Cell fires off signal that carries thru axon Tail end terminal releases chemicals into the gap between neurons synapse Chemical message received by other neuron s dentrites Average neuron attached to 10 000 others Soma cell body provides energy and makes proteins Signals often pass thru soma Action potential AP electrochemical signal passing thru axon Myelin sheath protects axon makes signal travel faster Oligodendrocytes make up myelin sheath inside brain Schwann cells make it up outside Brain Blood Barrier brain s blood supply separate from rest of body s Glial cell types Astroliga filters between brain bloodstream Filters nutrients waste viruses Oligodendrocyte Microglia CNS immune system Glia don t create action potentials or send long distance signals Cajal founder of modern neuroscience Neuron Theory brain is made of many separate neurons Action potential is all or none either it is passed on or it isn t Whether a neuron can have AP depends on cell membrane AP caused by movement of charged ions across membrane Resting potential Ion balance Inside of cell is more negative than outside Voltage dif in electrical potentials Baseline resting potential 70 mV per cell Cell follow gradients Gradient particles want to move to other side to balance things out Electrical gradient ions want to move to oppositely charged area Chemical gradient chemicals want to move to area of lower concentration Equilibrium both sides are balanced Ex Sodium is positive Na and has high concentration outside cell If possible will really flood inside the cell Like when the blood has too much salt in it from food etc Ion chennels Membrane has ion channels built into it Channels are either pump voltage or ligand Some may be specific to certain ions or be more general Ions pass thru channel in the direction of the gradient Ex Sodium Na goes thru ligand channel and floods into cell Membrane is depolarized becomes less neg more pos More sodium channels open and more floods in Membrane
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