Kog-neu Notes - PDF

Demarcation Problem (Named after Karl Popper): Science vs Pseudoscience (how to differ science from pseudoscience) (Falsifiability tackles this) Pseudoscience: Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual, but are incompatible with the sci...

Demarcation Problem (Named after Karl Popper): Science vs Pseudoscience (how to differ science from pseudoscience) (Falsifiability tackles this) Pseudoscience: Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual, but are incompatible with the scientific method. Neuromyths: Are misconceptions about brain research and it's application to education and learning The Freud Problem: When a person becomes to famous and get faithful followers, almost like a religion, they can say almost anything and people could believe them. They become to influential. This could lead to spreading of misinformation and a lack of scienfitic evidence in the claims. This is a contributing factor of why psychology is not associated with science by many. Pop-psychology: Psykological explanations or claims of a psychological character that don't have a scienfitic basis. Parapsychology: Psychology made and consumed for entertainment, focuses on alleged psychic phenomena and other paranormal claims. Philosophy of science: A bransch of philosophy that tries to answer the question: “What is science”? Scientific realism (a part of Philosophy of science). Realism: The thesis that something really do exist. – Scientific realism says that the world that appears to us is not reality itself. We do not see reality directly how it is. What our mind feed us is not reality itself, but like a shadow, image or simulation of reality that our minds contruct based on our interputations of reality. – Some deeper, hidden, invisible reality DO exist beyond our experiences and perceptions – This reality exists independent of human minds, activities or human beliefs. The hidden reality have a structure in itself and exists independently. Scientific models descriptions of the “deep structure of reality”: – Cell theory – DNA structure – Neurons The TRUTH: A correspondence between the description of reality and reality itself. Therefore, the descriptions of reality can be evaluated as true or false or have varies degrees of truth. Truthlieness: Verisimilitude. With time, theories move closer to the truth, their degree of truthlikeness increases. New theories correspond to reality better than old ones. Scientific theories that are highly tested and mature: – Are true – Correctly describe what kind of things there are in the world – Correctly desribe how things are related and how they behave – Tell us how the world is – Reveal the deep structure and hidden order of the universe Reality always responds predictably and accurately when we interact with it according to true theories Reality “resists” interactions based on false theories. Anti-realists believes that theories are just tools to control nature with, but they do not describe any “reality” behind the theories. Theories are just “narritives” describing subjective ideas and beliefs. There is no objective truth. Theories are a human contruction and refect human mind, thinking and language, not an objective reality independent of humans. The defining Characteristics of science: (Meaning = To be science, it must be:) 1. Testability: Any statement in science must be testable without privileged subjective sources of knowledge or personal revelations of “knowledge”. 2. Falsifiability: A theory must be able to be proven false (have falsifiability) to be defined as science. The criterion of Falsifiability is a solution to the Demarcation problem. Karl Popper (1902-1994) was a famous philosopher of science and came up with the term “Falsifiability, which is a characteristic of Science. A theory: Is an interrelated set of concepts used to explain data and make predictions about the result of future experiments. Scientific theories make specific, testable and risky predictions, and it must have predictive power. A hypothesis: Specific predictions derived from theories (which are more general) Currently viable theories: Those that have had many of their hypotheses confirmed. If a theory explains everything, it explains nothing at all. Unfalsifiable theories Freud: – Development of personlity, anything goes. You either turn out like you were as a child, or an adult version of your child-self, or complete opposite. Explains EVERYTHING and therefor nothing, unfalsifiable. – Root cause of autism (refridgerator moms) – Touretts syndrome (unconcious repressed urges surfacing) Einstens theory that space is bent by gravity. It was a specific, risky prediction with predictive power, and was proven right. 3. Scientific publishing and public critisism of any statement: A new finding must be critically evaluated by other scientists. Peer review: All scientific findingt are first published in “peer-reviewed journals”. How? Writing of manuscript: Write methods, finding, conclusions Submission to journal editor: decides if the paper is right for their journalInitial editorial evaluation: A large group of experts scrutinize it External review Reviewer's reports Editorial decision to reject, revise or accept After publication the findingt should be replicated by others. Replication crisis: The result of an old study may never have been replicated with new, modern methods and therefore the original findings and results could be questioned.  4. A self- critical attitude: Every scientist should be critical of their own results and favourite theories. They should also accept critisism towards their work and give up in case of being proved wrong. Example: Camillo Golgi theory vs Ramon y cajal Two scientists were debating wether neural tissue consists of individual cells (what we now call neurons), and separated from each other, or that the neural tissue has no gaps and that the neurons are not individual units. Golgi= network theorist (reticular theory) Cajal= Neuron-theorist. Ramon discovered the synaps (gap) between neurons and he made these observations using Golgis invented microscope. Cajals observations falsified Golgis theory. They both shared to Nobel prize but Golgi was so bitter that he (in their speech) promoted his already falsified theory, even though Cajals theory was proven to be right. He was lacking a self-critical attitude. 5. No absolute authorities in science No person or theory is above critisicism in science. Anybody could be wrong. Newton was wrong in Alcemy and Einstens was wrong about quantum mechanics. Statements are only evaluated on the basis of the evidence that can be shown to back them up. 6. Self-correction, Progress Science is an open, self-critical belief system that is never final but in constant change. New evidence is constantly found and science must be “self-corrected” by the person behind the theory, if it comes to that. This is how scientific descriptions of the world move closer to the truth. Cognitive neuroscience can be called “The biology of the mind”, “The science of the mind-realm”, “The connection between the body and the soul”. What neuroscience wants to answer: Where is the soul? What is the function of the brain? Dualistic view: Soul/mind is completely seperated from the body. Ancient Egypt: Dreaming was of interest and one of the sources of evidence they had that the soul was seperate from the body. Sleep is a state of the body, a state quite near death. Body shuts down and the soul is free to seperate from the body. They believed that dreams is an adventure of the disembodied soul where the soul could enter a spiritual realm. In the mesopotanien-region they believed in an underworld on the other side of earth, that we “fall” into when we “fall” asleep. The idea was that the soul travelled and could meet spirits/gods/messengers from God/ancestors. The messeges was often symbolical and therefor dreaminterputation was needed to interperet them. 2 parts of the (5 part soul) egyptians believed in. Ka= creative or divine power or the living physical body ba= soul, able to travel beyond the physical body Trepanning/trepanation: Prehistoric cultures: They were drilling holes in skulls of living people. Likely done to treat headaches, convulsion and insanity, “spirit possession”. Anima, Animus = “life, soul, spirit” Ancient Greece: Dualistic view just like the Egyptians. They had a God for sleep and a God for death, (brothers) which symbolises the same dualistic view as the Egyptians had with a separate sould and body. Dreams also had their own Gods in Greek mythology, the most famous one being Morpheus. He was a meggenger av Gods and he imitated people when he came to people in their dreams. Aristotle (philosopher) had a Cardiocentric view. He believed that the hart is the center of intellectual and perceptual functions. He believed the brain's job was temperatur-control, to cool down hot blood rising from the heart. This theory spread wide among Egyptians, Mesopotamians, Jews, Hindus and earlier Greeks. Hippocrate = The father of medicine. He studied with various problems/injuries in the brain and came to the conclusion the the brain in fact is very important for our mental functions. He believed that all sensation, thought and control of the body are in the brain. He gave a purely materialistic account of body and mind. Plato, famous philosopher and teacher of Aristotles, did not accept this materialistic humoral theory. He instead believed in a soul with three parts. 1. Reason and perception in the head (Nous, the rational soul) 2. Noble Passions, such as courage and pride (heart and lunge) 3. Base passions, like greed and lust (liver and guts) GALENOS Became a famous doctor of roman emperors, a leading practioners of his time. He was a surgeon for the gladiators, served as court physician for the Emperor in Rome, wrote hundreds of studies. He relied on animal dissections, experiments, clinical practise and perhaps observations of wounded gladiators. He concluded that the brain is the organ of sensation and voluntary movement. Speech does not come from the chest, brain does not cool the blood and the role of the nervous system is in control of our behavious. The Ventricle Theory: (Galenos theory) The brain (but not the brain tissue) is the seat of the soul and intellect. The intellectual soul has 3 parts. Imagination, cognition and memory, each one localized in 3 different brain ventricles, in form of cerebrospinal fluid. (The soul and mental faculties were located not in the tissue of the brain but in the internal cavaties known as ventricles”. This theory persisted in Eurpope for 1500 years. 1500's: Gradually it became allowed to study human anatomy by studdying and dissecting corpses. 1500's-1700's First pictures of human organs were created for scientific purposes. The biggest/strongest contribution to this: Andreas Vesalius: Was a very famous anatomist that did dissections och human bodie and documented them in beautiful pictures, later published a book: “Human Corporis Fabrica”. He rejected the ventricle theoryon the basis that: Animals have ventricles too but NOT the faculties of the soul, so therefore it cannot be right. Vesalius work included a detailed anatomical desciption of the body, and the brain was included. He created the first “brain scans”, very detailed drawings of different brains, even had faces. René Descartes – His theory of the seed of the soul is perhaps the most influential theory ever in the history od philosophy. He studied animal brains (as far as we know), brain anatomy – real life observations. He claimed to have found the seed of the soul inside the brain, in the Pinealgland. It then radiates forth through all the remainder of the body by means of the animal spirits and nerves. He was a dualist and believed that the soul didn't “exist” anywhere in the body but rather was communicating directly with the brain through the pineal gland. Descartes Hydraulic mechanism theory: That our brain and nerves workes as a hydraulic mechanism, similar to water moving through pipes, worked by the pressure of the fluid. Electric fish (wondercure): In ancient Rome ancient Roman physicians trated different maladies by having their patient stand on electric fish. This method, (electrical therapy) came more into fashion in the 1700's. The brain was thought to be an electric generator, with the nerves as wires with electrical fuid. Luigi Galvani figured out that it was possible to stimulate nerves by experimenting on frog legs. He learnt that the nerves must somehow electrically transmitt a signal to the muscles for them to move. Later on this method was called “Electro therapy”. Electro therapy/Galvanism, was used as a “cure all” treatment in the 1800's. Many experiments were done on exposed brains of animals human corpses. Automism: – The brain can be dicided into anatomically and physiologically defined parts. Holism: – The brain cannot be divided into parts, it constitutes one unified network without any defined parts. The automistic theory was inspired by the “cell theory” in biology. The cell theory: Living organism are made up of cells and a single cell is the smallest unit of life. Everything in the world is composed of atoms. But this could not be studied until Cajal and Golgis reserch/invention. Functional Localization: Localizationism: Mental functions can be localized into different parts of the brain, the brain being a collection of specialized “mental organs” Emanuel Swedenborg: swedish neuroscientist made observations that follows: If this portion of the cerebrum is wounded, then the internal senses – imagination, memory, thought – suffer, the very will is weakened, and the power of its detemination blunted... This is not the case if the injury is in the back part of the cerebrum. Anti- localization: (One holistic mechanism) different functions cannot be localized in different parts of the brain. The whole brain does all the brain functions, each function activates the whole brain. Karl Lashley: Holistic camp, neuroscientists. Hi carried out rat experiments with labyrinth tasks when the rats had lesions in different parts of the brain. This he did to figure out if he was right in his holistic, anti-localization theory. He concluded (though completely wrong) that the size of the lesion was relevant, but the location. Phrenology: rejected the “spiritual” side of things and believed that the mind is a biological phenomenon that can be studied empirically. The mind is located in different parts of the brain. No non-physical soul. He believed that the mind can be separated in 27 faculties and came up with where they were localized by mapping. Some of the names (parts) made a bit sense but some, like planning, hope, imitation, were weird. He also believed that the size and mass of the brain determined the level of general intelligence. Phrenology led to “head analysis” were people could go to get their skull measured to get an analyze of their future and their prospects, kind of like astrology today. Broca: Came to the conclusion that language production is located in the frontal lobe. Broca aphasia: A lesion in the Broca leads to that the person has difficulty producing speech, but understands what is being said. The Broca's area is closely connected to the motor cortex, (what controls the muscles). Wernicke: Came to the conclusion that language comprehension is located in the left temperal lobe. Wernicke aphasia: A lesion to the Wernicke leads to a lacking of understanding language. A person could speak fluently, but not make any sense at all. Wernicke's area is close to the auditory cortex (the part that needs to perceive sounds and analyze them before it's decoded in the Wernicke area. Anomic aphasia: Difficulty to finding the right words – because another certain part of the brain is damaged, such as names for objects etc. Phineas Gage: The railwayworker that suffered severe braindamage by an ironbar that went through his head. “Frontal lobe syndrom”. The localization of these higher cognitive functions was correct. Wilder Penfield: (prominent of the holistic idea). He performed direct stimulation of human cortex. To study which parts of the brain that were functioning and what function it may have, he used a small electrical stimulator and created a electrical current in the brain. These experiments proved evidence for showing that different functions are localized in different parts of the brain. Functional explanation: Cognitive science had the philosophical idea called the “computer metaphor” of the mind. That the mind and brain worked similar to a computer. The output is then our behaviour. Our brain have different parts with different functions, just like a computer does. Patterns of performance: - Measurable aspects of behavious in a task for healthy brains. This could be measured in the Stroop Task. Gives linguistic information and information on colous so these parts get activated in the brain and must work together. The test shows their mental capacity and function of the patient. Facilitation effect: How much faster responstime for (colour matches words) compared to randon colours. Interference effect: How slower of a responstime for (colour doesn't match word) compared to neutral (random colours) Total Stroop effect: You get this by comparing the easist stimuli (words and colours matching) with the conflicting stimuli (words and colours doesn't match). Functional Decomposition: When you look at patterns of performance during tests with stimuli – functional decomposition means the breaking down of the function into smaller parts. Patterns of performance – patients with brain damage: “The combination of perserved and damaged cognitive functions.” There are 3 types av Patterns of performance. When a brain is damaged, neuropsychologists try to get an accurate picture of what mental functions have been compromised and what functions still work perfectly. This is done by looking at the patterns of performance. Association: When a brain lesion happens in a certain brainpart and the fate of certain cognitive abilities are shared – for example the ability to recognize objects and faces. Dissociation: Reveals that two functions in the brain are different both cognitively and anatomically. (One function is damaged and one function is intact. Double Dissociation: When two single dissociations happens in the opposite directions. For example when 1 patient recognizes objects and not faces, and another regognizes faces but not objects. Only when this occurs, a double dissociation that is, we can truly determine that two functions are independent from each other. Laboratoy experiments in cognitive neuroscience: You have to design a task in which the cognitive components can be manupulated “turned on/off”. Measure brain activity when the subject is carryings out the critical task and compare it to an otherwise similar situation when he is not. In neuroscience we need convering evidence, evidence from multiple sources that points to the same direction. Hierarchical description and explanation in science: The world is composed ot these hierarchys of organization, to answer one hypothesis you might have to descend to another level in the organization. (Like to understand how a cell works you have to look at what the cell is composed of. Hippocampus: Creates Spatial map Gross Neuroanatomy: Brain Dissection. Oldest method, only possible post-mortem, reveals main structure and connections of the brain. Fine Neuroanatomy: Requires microscopy, which requires a sample of tissue, tracer stains, fixation, staining method and microtome (slicing of the brain). Brodmann: Created on the first brain maps. He published his maps of the cortical areas in humans, monkeys and other species in 1909. Connectomics: The bransh of neuroscience that tries to map the whole brain at many levels of organization. Microscopic connectomics – map the brain on a very small scale. Microscopic level: neurons and synapses Macrolevel: brain networks and underlying cognitive functions. Cartography: Mapping the connectome Neurophysiology: Measuring the activity of single neurons or a small group of neurons. Done with microelectrodes (small needles). This “needle” is inserted in a place where it can pick up a signal from the neurons, that then can be amplified and recorded. Brainscans: Structural: CT – radiation – virtual slices – major structure MRI – magnets (field) gives radiofrequency, when turned off, sensors detect released energy. After pulse – echo. Signal = location. Intesity = type of tissue Functional: PET – radioactive isotopes – tracers – emitts energy – creates “explosion” - picture where gamma rays collide. Slow and low quality. FMRI – magnetic field – electromagnetic pulses – creates echo – signals reflect location and structure. BOLD-signal (increase in neural activity in this method cause blood directed to the area which is what is measured. Slow, but good temporal. Electromagnetic Sensing: EEG – records brainactivity – electrogram of spontaneous electrical activity in the brain (active neurons). Electrodes – grid pattern – picks up electrical signals. EEG can measure ERP (the measured brain response of specific event) Fast in time, not acc. In space MEG- uses magnetometers – measuring magnetic fields (created by electrically active neurons) – picks up neuromagnetic signals. Fast in time, not acc in space. Spatial resolution refers to how accurate in space is that image that we can pick up. How many pixels does your image contain, that effects how accurate and clear the picture is. Low spatial resolution - not so clear scanns High spatial resolution - very clear scan Temporal resolution - The minimal time interval required to obtain a sufficient number of signals for the construction of an image. Low temporal - takes a long time High temporal - is quick TMS: (Transcranial Magnetic Stimulation) Is a form of medical exam and treatment. Electromagnet is placed on scalp This produces a magnetfield which introduces an electrical field in the brain. This effects the neurons in different ways, depending on which part of the brain is stimulated. Is used to treat depression tACs (Transcranial alternating current stimulation) Is a non-invasive brain stimulation. Sinusoidal alternating electric currents are delivered to the scalp to affect monstly cortical neurons. tACs is supposed to mululate brain function and cognitive processes by entertaining brain oscillations and inducing long-term synaptic plasticity. tDCs (Transcranial direct current stimulation) A form of neuromodulation that uses constant, low, direct current delivered via electrodes on the head. Treatment for depression and anxiety. (This is an open surgery procedure)