Intro to Neuroscience Week 1
Intro to Neuroscience Week 1 NE 101
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This 8 page Class Notes was uploaded by Noemie Trocher on Saturday September 10, 2016. The Class Notes belongs to NE 101 at Boston University taught by Lipton in Fall 2015. Since its upload, it has received 7 views. For similar materials see Introduction to Neuroscience in Neuroscience at Boston University.
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Date Created: 09/10/16
Intro to Neuroscience Chapter 1: What is Biopsychology? Neuroscience: the multidisciplinary study of the nervous system and its role in behavior The Origins of Biopsychology: - Biopsychology: branch of psychology that studies the relationships between behavior and the body, particularly the brain - Wilhelm Wundt: established the first psychology laboratory in Leipzig, Germany in 1879 - Prescientific Psychology and the Mind-Brain Problem ● Deals with what the mind is and what its relationship is to with the brain ○ does the mind control the brain, or does he brain control the mind? ○ are they the same thing? ● Mind should be thought of as a collection of actions the brain does; it is just a concept -> this is known as monism ● Monism: the idea ha he mind and body consist of the same substance ○ materialistic monism: position that the body and mind and everything else are physical ● Dualism: idea that the brain and mind are separate ○ believed that the body (brain) is material and the mind is nonmaterial - Descartes and the Physical Model of Behavior ● Model: a proposed mechanism for how something works ○ can be a theory, or simple organism or system ● Rene Descartes’ brain model: ○ used hydraulic model to explain brain activities ○ believed nerves were hollow tubes that “animal spirits” flowed through -> allowed muscles to move, sensations, memories, and other mental functions ○ “animal spirits” were pumped through the body by the pineal gland (Descartes believed it was the “eat of the soul”) ○ of course he was very wrong ○ shows how empiricism was used during the Renaissance ○ Empiricism: the gathering of information through observation rather than logic, intuition, etc. - Helmholtz and the Electrical Brain ● Late 1700: Luigi Galvani was able to make a frog’s leg move with electricity w/out the the nerves of muscles ● 1870: Gustav Fritsch and Eduard Hitzig produced movements in dog by stimulating the exposed brain -> discovered it was nerves operated by electricity that made the body move ● Hermann von Helmholtz calculated the speed of electricity in the brain *90 feet/second, which is less than the speed of electricity ○ proves that nerves do not act like wires ○ His theories of vision and hearing gave psychologist an idea of what he mechanical mind might look like - The Localization Issue ● Emerged in the early 1900s ● Localization: the idea that specific areas of the brain carry out specific functions ● Medical cases in the mid 1800s supported the idea of localization ○ Phineas Gage had a rod launched through his frontal lobe - he remain the same except he became profane and was unable to conform to social conventions ○ Paul Broca did an autopsy on a man who had lot the ability to speak and saw that only a small part of the left side was damaged (known as Broca’s area) ● Extreme theories of localization: ○ Phrenology: each of 35 different “faculties” of emotion and intellect was located in a precise location of the brain ○ Equipotentiality: the idea that the brain functions a an undifferentiated whole ● Today’s research ○ Function are both distributed and localized ○ Believes that parts of the brain work together in order to make an experience of behavior Nature and Nurture - How important is heredity to environmental influences in shaping behavior? - The Genetic Code ● Gene: biological unit the direct cellular processes and transmits inherited characteristics ○ 46 chromosomes and 23 pairs ○ most located in nucleus but some are in mitochondria ● Sperm cells and eggs only have 23 chromosomes ○ combine during fertilization to make 46 ● Zygote: fertilized egg ○ Undergoes rapid cell division to become a properly functioning organism ○ Organism is called an embryo for the first 8 weeks then is referred to as a fetus until birth ● Genes are made of deoxyribonucleic acid, which is how they carry genetic information -> referred to as a double helix ○ deoxyribonucleic acid: a double stranded chain of chemical molecules -> looks like a twisted ladder ○ composed for 4 nucleotides: adenine, thymine, cytosine, and guanine ● Genes of the same function are paired up on each set of chromosomes ○ They can have the same function but different affects ○ Alleles: different versions of the same gene ● Alleles; ○ Can be dominant or recessive ○ 2 dominant/recessive alleles -> homogeneous gene ○ 1 dominant + 1 recessive -> heterozygous gene ● Genotype: combination of alleles ● Phenotype: physical characteristic of combined genes ● Recessive genes can produce effects on unpaired genes (X chromosome) ○ referred to as X-linked genes ● Characteristics can be determined by a pair or several genes ○ Polygenic: many characteristics are determined by several genes - Genes and Behavior ● Used to be believed that learning was the major influence on behavior ● By 1992 the idea that behavior can be related to genetics became more accepted ○ Ex: mental illnesses, sexual orientation, and personality characteristics can be related to genetics - The Human Genome Project ● 1990: Geneticists from20 laboratories began a project to identify all the genes in the human DNA -> known as the human genome ○ Goal: mad the location of all the genes on the human chromosomes and determine the gene’s codes ○ Within 15 years the entire human genome was sequenced ● Discovered that only 3% of DNA is protein encoding; the other 97% of noncoding genes is related to behavioral complexity (used to be called “junk” DNA) ○ Some non coding DNA is inactive; left behind during evolution ○ Other noncoding DNA controls the expression of genes ■ Expression:the translation of their encoded information into the production of proteins -> controlling their functioning ● What do the genes do? ○ Gene map helps to find which genes may be causing a behavior or disorder ● Gene mapping will help improve the understanding of human behavior - Heredity: Destiny or Predisposition ● Most did not like the idea that behavior was genetic ○ Meant that they were “clones” of their parents ● Although a hallmark of genetic influence is diversity ● Genes and Individuality ○ Sex cell only receive a random half of a parent’s genetic chromosomes -> a parent can produce over 8 million different combinations of chromosomes ■ Sexual reproduction increases individuality ○ Supports Darwin’s theory of natural selection ■ Natural selection: those whose genes endow them with more adaptive abilities are more likely to survive and pass off their genes ○ Gene function has the capability to change over time ■ Can be turned on or off ■ Production can be increased or decreased ■ Genes can change their function later in life -> contributes to aging ■ Some genes can change based on experiences in life ■ Contribute to the fact that humans are different from other animals ->mainly due to increased gene expression in the brain ○ Genes can have varying degrees of effect ● Heredity , Environment, and Vulnerability ○ Heritability: The percentage of the variation in a characteristic that can be contributed to genetic factors ○ Only half of behavioral characteristics can be attributed to heredity -> the other half is due to environmental influences ○ Heritability only counts the proportion of variability that is due to genetic influence ○ Vulnerability: genes contribute a predisposition for a disorder, which may exceed the threshold required to produce the disorder Intro to Neuroscience September 7, 2016 Today’s Goals: ● Mind and Brain ● Course Overview Mind and Brain: ● What makes the human brain different? ○ Symbolism: humans are able to understand and manipulate the meaning of symbols (e.g. signs, language, formulas) ○ Has nothing to do with the number of neurons in the body (elephants and whales have more neurons) ● Current technology allows us to... ○ See and visualize neurons ○ Add or remove particular neurons ○ Manipulate genes inside the brain ○ Look inside the human brain and manipulate the mind ○ Alter the different areas of the brain (figure out which part of the brain controls what) ● Questions to be answered ○ How do we make sense of the brain? ○ How we go from the brain to the mind? September 9, 2016 Roots of Neuroscience - Origins of Modern Experimental Neuroscience ● 4 main questions about brain and behavior ○ 1.) Connection- circuiting? ○ 2.) Cognition- Psychological processes? ○ 3.) Compartmentalization- Regions and functions? ○ 4.) Cure- How do we take advantage of information? (technology and its uses) ● Connection- What does the circuiting looks like? ○ Neurons and synapses -> Neural circuits -> Brain systems ○ Camillo Golgi (1873) and Ramon y Cajal (1889): Reticular vs. Neuron theory ■ Reticular theory: brain is made up of a nerve net ● Neurons are connected, and are NOT discreet ■ Camillo and the Black Reaction: ● Able to stain the inside of a neuron but not the outside ● Believed that the neurons were physically connected ■ Cajal used the Black Reaction to say that the neurons are NOT connected ● Identified individual pieces (dendrite -> neuron -> axel) ● Says that the number of connections the brain is able to make relates to intelligence ○ Galvani (1791) ■ Conduction by fluid or electricity? ■ First to identify that electricity flowed through the neurons, not fluid *electrical transmission* ○ Otto Loewi (1921) ■ Is the communication between cells by fluid or electricity? ■ When the first heart was stimulated, the second heart had the same reaction as the first ■ Acetylcholine -> compound in the brain that acts as a neurotransmission (is both chemical and electrical) ○ Charles Sherrington (1897): The reflex arc ■ How do elements work together to perform functions of the brain? ■ Claimed that higher level functions were complex reflexes ● Cognition- How are psychological processes supported by the brain? ○ Hermann Ebbinghaus: formalized the study of memory ■ The forgetting curve ■ Used a quantitative approach ○ Ivan Pavlov: Reflex circuits for learning -> conditioned reflex ■ Learning is like a psychic message to the brain ■ Conditioned reflex is a learning reflex ■ Higher learning is related to reflexes ○ Karl Lashley (1929): ■ Performed experiments on mice ■ Believed that the motor part of the brain was in the front while the sensory part was in the back ■ Removed parts of the brain to see if the performance of the mouse going through a maze would decrease ■ Did not notice a difference when he removed specific parts of the brain ■ After a while he noticed that at he removed more of the brain the lower the performance of the mouse was -> equipotentiality ■ Came up with the Law of Mass Action: the more brain that is damaged the lower performance is