Recovery from brain damageinjury Destruction of neurons forces other neurons to

Recovery from brain damageinjury destruction of

This preview shows page 39 - 42 out of 50 pages.

Recovery from brain damage/injury Destruction of neurons forces other neurons to take over the lost functions for recovery Surviving neurons can restore functionality by modifying themselves structurally or biochemically o Structurally: sprout new dendrites or extending axons to form new synapses o Biochemically: release more neurotransmitters Recent findings suggest that brains of mature primates and humans are capable of producing new neurons (neurogenesis) Brain is capable of greater plasticity early in life o Because 1 to 2 year olds have 50% more brain synapses than mature adults do Unused or weaker synapses deteriorate or suicide with age, so brain loses its plasticity
Image of page 39
Genetics – Heritability & Disorders 09/12/2013 October 10, 2013 ° Genetics of Behaviour: Nature vs. Nurture ° Nature: something we’re born with ° Nurture: something we learn Genes: strand-like molecules of DNA that are linked on chromosomes Karyotype: genetic blueprint XY male XX female ° Genes (DNA) RNA proteins molecules (sequences of amino acids) ° ° Protein synthesis can influence all your attributes. Genes influence protein synthesis, and can help to determine the range of possibilities – not to what degree you will express them. There are no genes for a particular attribute. There is no gene for intelligence, but many people measure intelligence by reaction time. ° ° Environment can influence protein synthesis as well; environment can contribute to the degree of expression of genes. Environmental exposure at specific interval is critical (i.e. white- crowned sparrow must hear adult song between 7 th and 60 th day or it will never sing that adult song!!!) Environmental triggers (in critical periods) are important in gene expression. ° ° Important to distinguish between genotype vs. phenotype: Genotype: set of genes inherited Phenotype: outward expression of genotype (characteristics, behaviours, etc.) o Dominant vs. recessive Outward characteristics may not indicate underlying genetic contribution. Homozygous (identical) vs. heterozygous alleles (not the same) o Homozygous alleles make genotypic predictions easy
Image of page 40
o Heterozygous involves finding dominant and recessive alleles Codominance (i.e. sickle cell anemia) ° ° Polygenetic Effects : traits related to action of more than 1 gene or chromosome (more than one gene codes for a trait) Recombinant DNA procedures : using certain enzymes to cut long molecules of DNA into pieces, combine them with DNA from other organism and insert them into host organism Gene knockout procedure : deactivates one gene to observe effect on behaviour o Example: insert genetic material that will prevent neurons from transmitting serotonin (knockout mechanism for serotonin reuptake), causing very anxious behaviour o Problems: very few behaviours are controlled by on gene, disruption of gene may affect a wide range of functions, and ethical considerations ° Calculating heritability: H 2 = variance due to genes/ total variance Estimate of how much observed variability due to genetic alone H 2
Image of page 41
Image of page 42

You've reached the end of your free preview.

Want to read all 50 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture