Behavioral Neuroscience Exam 1

Behavioral Neuroscience Exam 1

1. Neuroscience: attempt to understand how the brain functions. The brain is one organ, but studied at all different levels (physics, biology, chemistry)

   • Behavioral Neuroscience: Studying the behavioral output of the brain. Examples: what does the brain look like when viewing violent images? What in the brain is causing a certain behavior?
     • Origins of Behavioral Neuroscience
       • The mind-body problem: the mind is different than the brain, is the mind physical or not? Non-physical things can't have action in the physical world.
         • Monism
           • Idealistic monism: all nonphysical
           • materialistic monism: all physical If the body dies, the mind dies
         • Dualism
           • The mind and brain are separate. Brain = material; mind = nonmaterial
       • Model: proposed mechanism for how something works
         • Descartes and the Hydraulic model
           • animal spirits and the pineal gland. Spirits fill tubes, brain says where fluid goes. believed soul had to leave the body. When human died, pineal gland shrunk, Descartes assumed that's where the soul resided.
           • Empiricism: information through observation
           • Helmholtz and the Electrical Brain
             • Dicovered electrical properties of brain different from electrical wires. Proposed additional biological/chemical components
             • Localization
               • Phrenology (personality and skull shape. Different faculties located in precise areas of the brain. Based on plausible premise. Bumps on skull match bumps on brain. Determinism
               • Equipotentiality
                 • Brain functions as undifferentiated module. Brain seems adaptable. Neurons everywhere.
               • Current research shows that the brain exhibits both Localization and Distribution of function
       • Nature and Nurture
         • Nature vs. nurture question How important are environmental influences (nurture) in shaping behavior? To address confusion, it’s necessary to understand what nature and heredity are!
           • Genetics/Heredity
             • Gene: fundamental unit of inheritance Direct cellular processes found on chromosomes 16% encodes proteins Chromosomes: Body cells: 23 pairs Sex cells: 22 pairs, 1 sect of sex chromosomes XX female XY male
               • DNA: Deoxyribonucleic acid (DNA) Double stranded chain Contains directions for making proteins Bases (A, T, G, C) are the genetic “alphabet”
                 • Allele: Spice of life, different versions of genes Determine exact function of proteins One per chromosome Dominant, recessive, or somewhere in between Homozygous and Heterozygous Genotype: carrier gene, not expressed always, dormant Phenotype: Actually expressed, not dormant X-linked traits: gene on X chromosome, male colorblindness
                   • Homozygous vs. heterozygous Genotype vs phenotype X-linked traits
                   • Traits determined by Single pair of alleles (relatively rare) Several genes, referred to as polygenic traits Height Intelligence Skin color Psychological disorders Important: Genes do not provide a script for behavior, they control the production of proteins
             • Genetic Research and the Brain
               • Genes produce proteins Genes don't provide the script Proteins + Environment = Behavior Example: Human Genome Project 20-25 thousand functional genes 97% DNA is non-protein-encoding Active in gene expression Human-specific DNA → mouse Produced protein = thumb-related stuff Ability to modify thumb= piece of DNA that doesn't encode protein, but not "junk DNA"
             • Why do we care about genetics?
               • Heredity: destiny or predisposition? Sexual reproduction increases variability in offspring and does not create clones Principle of natural selection Individuals whose genes provide them with a greater ability to adapt are more likely to survive, and pass on these beneficial genes to more offspring
             • Heredity and Heritability
               • Heredity: destiny or predisposition? Inheritance of genes is not the only factor that determines phenotypic outcomes Genes can be turned on or off based on development and experiences Heritability: percentage of variation in a characteristic that is attributed to genetics Can be calculated by comparing concordance rate for twins If one twin has a trait or disorder, does the other twin?
                 • Concordance rates Medical disorders Behavioral disorders: higher concordance rate, hundreds of genes contributing to this variability and behavioral characteristics. Epigenetics Loop: genes → environment → genes Vulnerability: more genes for a disorder reduces the threshold required to produce it.
                   • Variability in behavioral characteristics result from Interaction of genetic and environmental influences “Nature and nurture” Vulnerability More genes for a disorder reduces the threshold required to produce it Today, most scientists reject the nature versus nurture concept

2. Behavioral neuroscience developed out of empirical methods applied to the biological basis of psychology

3. Most neuroscientists believe that all mental activity are a product of brain activity (mind-body problem)

4. Many behaviors have local but interconnected functions within the brain

5. Many behaviors are genetically influence by contributions from many genes

6. Nature and nurture contribute to behavioral characteristics

7. The field of behavioral neuroscience is still in it infancy even though much progress has been made