brain areas associated with most complex functions evolved the most PSY 0010 Biopsychology page 1 Biological psychology nervous endocrine systems neuroscience interdisciplinary study of the brain Brain evolution dramatic increase in size relative to body size o started about 3 4 million years ago o proportionally big brained 3x weight of great apes brains o greater behavioral flexibility o adaptive advantage Human genome 46 chromosomes 23 pairs in each cell s nucleus 22 pairs identical 1 pair X Y Chromosomes tightly coiled DNA protein double helix o sugar and phosphate backbone o bases in pairs 3 million in human genome Genes segment of DNA unit of hereditary transmission 20 5k in humans comparatively small number carry info for protein synthesis o and to build maintain cells only 1 of DNA Genes and heredity genotype set of genes we inherit o blueprint o from each parent 1 base out of the pair o mutations and recombinations in genes phenotype observable traits o building always some variation from genotype o how genes are expressed Natural selection environmental pressures changes limitations competition for resources in and between species selection of fittest phenotype reproductive success genotype of fittest phenotype passed onto next generation frequency of genotype increases in next generation Contemporary evolutionary theory humans like all organisms are collections of mechanisms for passing on genes Dawkins the Selfish Gene PSY 0010 Biopsychology page 2 fitness quality of genes not humans gene is fit if it passes onto next generation individuals may be sacrificed o monkey who makes danger call more likely to be sacrificed but genetic pool of others will go on inclusive fitness success of entire group can be influenced by individual Genetic expression in phenotype variation between blueprint and building dominance vs recessiveness o alleles different form of same gene one dominant over another only dominant allele expressed Epigenetics 80 of formerly junk DNA are switches that turn genes on and off 4m switches influence phenotype o can have gene for something but if switch is off won t show environmental events can cause switches to turn on off changes in switches can be inherited o can still change back to unswitched if you inherit switched if you go through sufficient environmental events o e g starved children had smaller children and small children had smaller children small switch flipped Heritability extent that phenotypic variation differences in observable traits exists due to variation in genes individuals carry variations among individuals in a population o populations of different environments cannot be compared Behavioral genetics twin studies raised in same household o monozygotic identical genetically identical egg splits o dizygotic fraternal not identical about 50 2 eggs 2 sperm same time o characteristic correlation in both heritability index can be as high as 8 very strong correlation ideal same prenatal and familial environments o controlling for basically entire environment adoption studies how adopted children resemble biological adoptive parents o e g IQ strongly correlated to biological parents Molecular genetics sequencing of genome most of human genome identical for all PSY 0010 Biopsychology page 3 molecular geneticists look at genes with different alleles and behaviors characteristics o very few single gene monogenic transmissions o most genetic influences on behavior are polygenetic small contributions from many genes The nervous system central nervous system brain spinal cord peripheral nervous system everything else Peripheral autonomic o sympathetic division bodily arousal activated body mobilized to respond to danger stress o parasympathetic bodily calm regulates body for rest and digestion o work in opposition to each other complementary o regulate largely same functions at different times Endocrine system glands secrete hormones into system adrenal gland directly involved in activation of sympathetic nervous system signals Somatic nervous system brings sensory input to brain takes signals from brain to muscles glands movement Central nervous system spinal cord connects brain and neurons somatic nervous system spinal reflexes don t require brain o still happen when brain dead if spinal cord intact Bottom up view of brain brain stem extension of spinal cord menulla breathing heart rate blood pressure pons o regulates sleep cycles o connects cerebellum cerebellum o motor control o balance coordination reticular formation o attention and alertness o connected to pons sleep regulation Midbrain Forebrain tectum orientation tegmentum movement and arousal substantia nigra voluntary movement limbic system emotional center of brain PSY 0010 Biopsychology page 4 o networked with autonomic endocrine system o emotions pain pleasure o hypothalamus boss of endocrine regulates pituitary which regulates rest appetites emotions o amygdala particularly fear aggression emotional memory o hippocampus emotion experience sub cortical structures formation of long term memories easier to remember emotional events cortex cortex to motor o basal ganglia voluntary control o cingulate gyrus attention and cognitive control cerebrum topmost layer o thalamus conduit between information from nervous system and o cortex o corpus collosum bundle of nerves that bridges 2 sides of brain Cortex 2 spheres 4 lobes each Frontal lobe o prefrontal cortex language memory executive decision making o motor cortex signals to muscles via somatic system Parietal lobes o primary gustatory taste o mirror neurons mimicry empathy directly evolved with empathetic ability o space perception where body is located o L speech location o R object location o somatosensory cortex touch temperature pain Occipital lobes o visual cortex Temporal lobes o auditory cortex hearing language comprehension autobiographical memories o primary olfactory cortex The cooperative brain all areas of brain work together no process that doesn t involve multiple parts of the brain PSY 0010 Biopsychology page 5 most of cortex not localized association cortex o works with others in all 4 lobes still localization of function though Cerebral dominance brain function localized by hemisphere Left o processing style analytic sequential linear o positive commands o spontaneous production of language speech writing o memory words numbers o understanding speech writing o processing style holistic emotional spatial o negative