Lecture

• If a dominant allele produced a life-threatening disease, it would be selected against and usually would not get passed on; Huntington's disease is the exception; activates way letter on in life
• Behavioral genetics: branch of genetics that deal with inheritance of behavioral and psychological traits.
• Selective breeding: The process of breeding organisms to produce offspring with desirable characteristics.
• Selective breeding is useful within animals that have shorter lifespans
• genotype + environment = phenotype
• Twin/Family studies compares the prevalence of attributes across varying of genetic relatedness
• Fraternal twins are most likely as related to each other as other siblings(genetically), but the environment is much more similar to both of them because of the lack of a time gap
• Comparing Monozygotic and dizygotic twins allows researchers to determine whether genetics are at play for diseases/disorders
• Caveats to Twin studies: similarity of environment; often monozygotic twins share the same placenta or had similar childhood.
• Brain is the fastest organ to reach adult size
• In the first stage of conception, the embryo has a neural plate that becomes a neural tube. This is in place of a brain and neurons start developing 10 weeks into conception
• New neurons can be formed in the hippocampus after birth but mostly neurons have been with you since birth
• Myelination accounts for a lot of brain growth within infancy and early stages of development
• In the adult brain, myelination accounts for 50% of the brains weight
• Synaptogenesis is the growth of the axons and dendrites in the neurons, creating synapses and connections
• What accounts for brain growth in infancy: myelination and synaptogenesis
• At 1 years old, you'll have more synapses than you'll ever have; these redundant synapses are weeded out later on(synaptic pruning)
• Synaptic pruning starts at early infancy and then progresses into adolescence. Idea of if you dont use it, you lose it
• From ages 1-10, synaptic pruning has cut all synapses down by 40%
• In adolescence, there is another wave of overproduction and pruning. The physical growth parallels the brain growth. Within this period, the Corpus coliseum thickens and the prefrontal cortex matures slowly as well up to about 25 years of age
• 2 types of specialization in the brain are : where (the brain regions active in processing become more focused) and what(the kinds of stimuli that trigger brain activity become more specific).
• more specialization means less plasticity of the brain
• Criterial/sensitive periods are important in periods of development/learning
• 2 stages of brain growth are experience expectant and experience dependent brain growth
• In experience expectant brain growth, the brain changes because it expects regular/typical input. Our brains are prepared to experience inputs so that developments unfolds as planned; if those inputs are not present, there may be maldevelopment
• Visual and auditory development are examples of experience expectant brain growht
• In experience dependent brain growth: the brain grows in response to experience, not in anticipation of experience. An example is learning to play an instrument
• 5 to 10% of brain weight loss occurs between 20 to 90
• Dendritic growth increases from age 40 to 70
• The range of when babies start to walk is 8 to 16 months
• Maturational viewpoint: the unfolding of a genetically programmed sequence
• Experiential hypothesis: opportunities to practice are important
• The questions of why do babies start to walk can be answered through these viewpoints: Experiential hypothesis, dynamical systems theory and the maturation viewpoint
• Dynamical systems theory: motivation to explore drives infants to combine motor patterns in new ways