Last year

• Why study the brain

  • Our brains influence our thoughts and behaviours
  • There is still a lot that we don't understand
  • The brain is the most complex organ on Earth
• Behaviour


  • Overt (external) actions
  • Covert (internal, hidden) actions like learning, thinking, and emotion
• Types of behaviours


  • Innate behaviours
  • Learned behaviours
• Innate behaviours


  Inherited and fixed, e.g. fixed action patterns
• Learned behaviours


  Learn through experience, social or cultural transmission, classical or operant conditioning
• Aristotle's view


  • Brain not involved in producing behaviour, thought to cool the blood
  • Psyche: the mind, consciousness, immaterial entity that is the source of human behaviour
• Dualism


  The mind and the body are separate, both contribute to behaviour in humans, animals lack a mind
• Dualism: Descartes


  Mind connects to the body via the pineal gland, controls the flow of fluid through the ventricles to fill the muscles of the body and create movement, hydraulic pressure

  
• Why might dualism create issues for the study of Behavioural Neuroscience?
• Monism


  The mind and body consist of the same substance
• Materialistic monism


  The mind and body are physical
• Materialism: Darwin


  Behaviour can be explained by the body (specifically, the nervous system) alone, the mind does not need to be considered
• Electricity in the nervous system

  • Late 1700s: Luigi Galvani used electricity to stimulate nerves
  • 1870: Fritsch and Hitzig produced movement by electrically stimulating the brain
  • 1849: Hermann von Heimholtz demonstrated nerves do not behave like conducting wires
• Chemicals in the nervous system

  • 1907: Walter Dixon showed chemicals are also involved in signals, Vagal stimulation slows heart rate, Liquid around heart collected after this stimulation slowed another, unstimulated heart
• Localization


  Specific areas of the brain carry out specific functions
• Equipotentiality


  The brain can function as an undifferentiated whole
• Evolution


  Process by which species change over time due to natural selection
• Natural selection


  Process where heritable traits that confer a survival advantage in a specific environment become more prevalent in a population over time, not just survival of the fittest
• Population


  A subset of individuals of one species that occupies a particular geographic area and interbreeds
• Artificial selection


  Selective breeding, if you mate individuals with desirable characteristics, their offspring have those desirable characteristics
• Important terms


  • Heredity: passing biological traits from parents to their offspring
  • Gene: basic unit of heredity, genes influence our biological traits
• Gregor Mendel


  Heritable factors (genes) are inherited in predictable patterns and often express (turn on) similar outward (physical) traits
• DNA


  Made of nucleotides or bases (Adenine, Thymine, Guanine, Cytosine), order of bases stores information
• Gene


  Codes for proteins, antibodies, enzymes, hormones, structural bits, etc.
• Mutation


  Change in the DNA sequence of an organism that occurs because of errors, copying errors in DNA replication, mutagens, viruses, changes to the DNA sequence can lead to changes in the protein structure produced
• Mutations and natural selection


  Changes caused by mutations can be bad, neutral, or good, bad = removed from population, neutral = up to chance, good = adaptation
• Genotype


  A person's specific genetic makeup, present from birth and effectively unchanging

  
• Phenotype


  The observable characteristics due to the genetic makeup, can be altered by other genes, the environment, etc.
• Genetic information


  In somatic cells: 2 pairs of each chromosome, dominant allele produces effect regardless of which allele it is paired with, recessive allele has influence only when paired with the same allele, heterozygous: two alleles are different, homozygous: two identical alleles
• Alleles


  Different versions of a gene
• How does your genotype affect your phenotype?
• Colour dominance in peas

  • Brown Eyes Allele is dominant over Blue Eyes Allele, Blue Eyes Allele is recessive to Brown Eyes Allele
• Pleiotropy


  Genes that have more than one phenotypic effect
• Polygenic


  Traits influenced by more than one gene
• Modifier gene


  Can change the way a trait is expressed
• Polygenic transmission


  When a number of gene pairs combine to create a single phenotypic trait
• Epigenetics


  Lasting changes in gene expression during development that are not caused by the genes themselves, DNA Methylation: adding a methyl group to DNA (an "off" switch), Histone modification: chemical changes to histones (modify proteins that condense DNA, an "on" or "off" switch)
• Heritability


  A measure of how well differences in people's genes account for differences in their traits, can differ between populations

  
• Adoption studies


  • Share genes, but not environment, with biological relatives, share environment, but not genes, with adoptive relatives
• Twin studies


  • Separates genetic and environmental influences, agreement between adoption and twin studies increases confidence in results, Francis Galton - conducted first twin study in Britain in 1875, Monozygotic (MZ) twins: single fertilized egg splits into two genetically identical organisms, Dizygotic (DZ) twins: two separate fertilized eggs