CCJ4601 HUMAN BEHAVIOR FINAL EXAM REVIEW FROM BOOKSBeaver ch. 2, 5, 4Chapter 4Limbic SystemCerebral CortexPrenatal exposure to testosteronePrenatal exposure to toxinsHindbrain Structure and FunctioningMidbrain Structure and FunctioningStructures of the Subcortical (Limbic) RegionThe four Lobes of the Cerebral CortexCCJ4601 HUMAN BEHAVIOR FINAL EXAM REVIEW FROM BOOKS Beaver ch. 2, 5, 4 - Remember, the complimentary base pairs of DNA is always present, but not shown - The main function of genes is to code for the production of proteinso Only about 10% of the human genome actually codes for the production of proteins- Genes only contain the instructions needed for a specific protein to be produced- The central dogma of molecular biology: transcription and translationo Transcription: the process whereby a gene duplicates itself onto a new molecule called ribonucleic acid (RNA) Splicing transforms RNA into mRNA (RNA contains uracil (U) instead of thymine (T)o Translation: mRNA meets up with and attaches itself to a ribosomes, which are protein manufacturing machines found in the cytoplasm  On average, about 1200 base pairs, equating to about 400 amino acids, are needed to produce one protein - During transcription, a gene is copied from DNARNA. During translation, RNA works in conjunction with ribosomes to produce a protein. The protein is what is ultimately responsible for bringing about phenotypes- Genotypic variance has the potential to explain phenotypic variance - Genetic locus: location of where gene is found- Alternative copies of a gene are referred to as alleles and genes that consist of 2 or more alleles are called genetic polymorphisms - Polymorphic genes that consist of 2 identical alleles are said to be homozygous o Heterozygous is when the 2 alleles are different - SNP (Single nucleotide polymorphism): due to a difference in a single nucleotide base, where 1 alleles are indistinguishable except for a one-letter difference o 90% percent of all genetic polymorphisms are SNPso nonsynonomous: SNPs that result in the production of different amino acidso synonymous: SNPs that do not result in the production of different amino acids o approximately 85% of all genetic disorders, including terminal diseases, can be traced to SNPs - Microsatellites: result of allelic differences that vary in their end-to-end length, where one allele is longer than another allele o Surface because of differences in the number of times that a short section of base pairs is repeated - Minisatellites: repeat sequences that occur in much larger blocks of base pairs o VNTR: variable number of tandem repeats- 3 ways genotypic variance can produce phenotypic variance:- monogenic effect: one gene is the cause of one particular phenotypeo can be due to recessive or dominant patterns of inheritance- polygenic effect: the result of multiple geneso ex: human behavioral phenotypes too complex to be determined by a single gene- Pleiotrophy: captures the effects that a single gene has on various different phenotypes- How neurotransmitters can be discarded from the synapse:- The presynaptic neuron can produce a transporter protein that enters the synapse, caputres the neurotransmitters and returns then to the axon terminal of the presynaptic neuron (REUPTAKE)- Production of enzymeso Enzymes breakdown neurotransmitters into inactive particles- Enzymes and transporter proteins are both vitally important in maintaining normal levels of neurotransmitters in the synapseo The production of enzymes and transporter proteins in determined by genes, some of which are polymorphic - Dopamine is an excitatory neurotransmitter that activates postsynaptic dopamine receptors, making an action potential more likely to occur in the postsynaptic neurono Sleeping, eating and sex all stimulate the release of dopamineo Dopamine levels vary in part because of the different alleles that are inherited for these polymorphic genes - Serotonin is a neurotransmitter with inhibitory properties and the release of serotonin is thought to reduce innate drives, regulate behaviors and control impluseso Significant relationship between low levels of serotonin and antisocial behaviors o Levels of serotonin vary from person-to-person because of environmental factors and because of certain genetic polymorphisms that are involved in the production, transportation and degradation of serotonin Chapter 4- Brain weight approx. 3 pounds- More than 60% of the entire genome codes for the braino Some of the genes that code for the brain are polymorphisms, and different alleles for some of these polymorphisms have been found to correspond to variation in specific regions of the brain Limbic System- Generates emotions- Affects the endocrine system and the autonomic nervous system - Amygdala: vitally important to aggression and other antisocial phenotypes; emotional hub of the brain and is responsible for generating feelings such as anger, rage, and fear o Involved in emotional learning and fear conditioning (presence of a stimulus is paired with a response) - Hippocampus: involved in formation of long-term or declarative memorieso Vitally important to the laying down of new memories o Damage to the hippocampus will not erase memories but it will preclude the ability to form new oneso Also involved in emotional learning and fear conditioning- Thalamus: brain’s “relay station”o Receives incoming messages from systems throughout the body, organizes and prioritizes these messages and it then dispatches them to the cerebral cortex where they are processed - Hypothalamus: regulation of visceral functions, including the modulation of body temperature - When stressful situations are encountered, the hypothalamus emits the hormone, corticotrophin releasing factor (CRF). CRF triggers the pituitary gland to release the adrenocorticotrophic hormone (ACTH). Last, ACTH stimulates the adrenal glands to produce cortisol, which is the main stress hormone Cerebral Cortex- “cerebrum” or “neocortex” accounts for approximately 2/3 of the brain’s volume - corpus callosum: large bundle of fibers that allows the 2 hemispheres to communicate with each other - grey matter: neuronal cell bodies and their synaptic connections; has been found to be positively correlated with cognitive abilities and skills, including intelligenceo where info processing occurs - white matter: consists of myelinated axons (axons covered with a fatty sheath that increases the speed