Khan Notes on Neuroscience PDF

**The fusiform gyrus is a part of the visual system in the brain, and plays a role in high level** **visual processing and recognition. (part of temporal and occipital lobe)** The temporal lobes are responsible for processing auditory signals, interpreting visual stimuli, and language recognition...

**The fusiform gyrus is a part of the visual system in the brain, and plays a role in high level** **visual processing and recognition. (part of temporal and occipital lobe)** The temporal lobes are responsible for processing auditory signals, interpreting visual stimuli, and language recognition. The parietal lobes are responsible for spatial reasoning and receiving somatosensory information. **Visual agnosia** is a disorder of the ventral pathway, because it is an inability to recognize an image. (acronym: **V**isual = **V**entral) Synthestasia - a neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. **Ca**2+ = indicator of chelation. This positively charged ion is extremely versatile. A rise in this ion, postsynaptically, in dendritic spines is essential for activity-dependent plasticity. This ion is an important second messenger in the neuron. Abnormal amounts of signaling in this ion has been implicated in disease states such as Huntington's, Alzheimer's and schizophrenia. Informed Consent Beneficence /nonmalifiscence/autonomy **Antipsychotics** are a class of psychiatric medication primarily used to manage psychosis(including delusions, hallucinations, paranoia or disordered thought), principally for schizophreniaand bipolar disorder, and are increasingly being used in the management of non-psychotic disorders. Both types block dopamine pathways and cause Parkinson like symptoms. **(also treat anxiety with dementia, OCD, and anxiety disorder).** **Typical Antipsychotics** used to treat psychiatric conditions. **Neuroleptics**. Decrease positive symptoms of schizophrenia but can increase negative symptoms. First generation. The **atypical antipsychotics** (**AAP**; also known as **second generation antipsychotics** (**SGAs**)) are a group of antipsychotic drugs (antipsychotic drugs in general are also known as **major** tranquilisers**). Block serotonin as well. Less likely to cause extrapyramidal motor control** **disability (negative symptoms increase). these have increased risk of stroke, cardiac death,** **blood clot and diabetes.** The **Thomas theorem** is a theory of sociology which was formulated in 1928 by W. I. **Thomas** and D. S. **Thomas** (1899--1977): " If men define situations as real, they are real in their consequences. " In other words, the interpretation of a situation causes the action. (acronym: if Thomas the train is defined as real, it becomes real in consequence) 322 **Haptic perception** is the exploration of objects through touch, most often by the hand or fingers. **Active touch** occurs when a person uses haptic perception to actively inspect an object. **Adaptation** is at the sensory level, and habituation is at the perceptive/cognitive level **Phantom pain** is the perception of pain in an area of the body, which has been removed or lost due to injury. **Tonotopy** is the special mapping of sound frequencies that are processed by the brain, also called the tonotopic map. The **dermatome** is an area of skin with sensory nerve fibers from a single posterior spinal root ganglion. The **connectome** is a neural map of the connections within the brain. **The homunculus is a cortical body map of how different areas of the skin are** **represented in the primary somatosensory cortex (S1).** **Interference** occurs when the participant takes longer to read a word because it is emotionally charged than a neutral word. In psychology, the **Stroop effect** is a demonstration of interference in the reaction time of a task. When the name of a color (e.g., \"blue\", \"green\", or \"red\") is printed in a color not denoted by the name (e.g., the word \"red\" printed in blue ink instead of red ink), naming the color of the word takes longer and is more prone to errors than when the color of the ink matches the name of the color. Agoraphobia -- fear of open spaces, crowds, etc LSD -- serotonin neurotransmission Nicotine -- CNS stimulant by working as a acetylcholine agonist. Amphetamine -- dopamine reuptake blocked Alcohol -- CNS depressant Schizophrenia Positive symptoms are delusions, neologisms, and hallucinations. Negative symptoms describe loss of emotional affect and social withdrawal. Mesolimbic -- positive effects of schizophrenia Mesocortical -- negative effects of schizophrenia Dopamine release in the tuberoinfundibular pathway inhibits prolactin release in the pituitary. The nigrostriatal pathway is associated with motor planning and purposeful movement **The mesolimbic pathway is associated with reward, motivation, and many of the positive** **symptoms of schizophrenia.** Hypochondriac - a person who is abnormally anxious about their health. Illness anxiety disorder - Individuals diagnosed with illness anxiety disorder are often more concerned with illness or the idea of being ill and often lack or have minimal somatic symptoms. 323 The DSM-5 describes paraphilia as any intense and persistent sexual interest other than genital stimulation or fondling in phenotypically normal, physically mature, and consenting human partners. Paraphilias include sexual sadism (inflicting humiliation, bondage, or suffering), masochism (being humiliated, bound, or suffering), transvestic (sexually arousing crossdressing, in addition to voyeurism (spying on others) and frotteurism (touching or rubbing genitals against a non-consenting individual), and pedophilia (sexual focus towards children). A teratogen is a substance or environmental factor that can disrupt normative fetal development. Phenylketonuria is a genetic problem; consumption of diet soda during pregnancy would not directly cause phenylketonuria. Polycystic kidney disease is a genetic problem. Autism spectrum disorder is not a birth defect. **Fetal alcohol syndrome is directly related to the consumption of alcohol during** **pregnancy.** Neuropeptide Y in humans inhibit the feeding circuit blocking satiety. The inhibition caused by peptide Y may cause the inhibition of other neurotransmitters such as cholecystokinin (CCK), which limits meal size by sensing the distention of the duodenum. This may cause eating without being sensitive to the signals that the individual is full. The **paraventricular nucleus** (PVN, PVA, or PVH) is a neuronal nucleus in the hypothalamus. It contains groups of neurons that can be activated by stressful and/or physiological changes. Many PVN neurons project directly to the posterior pituitary where they release oxytocin or vasopressin into the general circulation. Other PVN neurons control various anterior pituitary functions, while still others directly regulate appetite and autonomic functions in the brainstem and spinal cord. Short-term maturation effects are physiological changes that can affect outcome measurements. Repeated testing that leads to extreme measurements becoming more normal is called regression toward the mean. Sensory stimulus is more referring to the type of information being received by your receptors which elicits a response\... i.e.: light, heat, touch, sound, etc. Proximal stimulus is the stimulation that actually occurs when your sensory receptors are activated\... the neural activity. Distal stimulus is the actual stimulus or object in the real world that you end up sensing and then perceiving, which results in the proximal stimulus. 324 **Proximal Stimulus**: In perception, the proximal stimulus refers to physical stimulation that is available to be measured by an observer\'s sensory apparatus. It can also refer to the neural activity that results from sensory transduction of the physical stimulation are the patterns of stimuli from these objects and events that actually reach your senses (eyes, ears, etc.) **Distal stimuli** are objects and events out in the world about you. The **distal stimulus** is an object which provides information for the proximal **stimulus**. The **distal stimulus** is an object which provides information for the proximal stimulus. The **proximal stimulus** registers, via sensory receptors, the information given by the distal stimulus. o An example would be a person looking at a shoe on the floor. The shoe itself is the distal stimulus. The image recorded onto the person\'s retina (sensory receptor) is proximal stimulus. o Another example would be a telephone ringing. The ringing of the telephone is the distal stimulus. The sound being recognized and understood as the ringing of a telephone, by our sensory receptors, is the proximal stimulus. **Word Association** is a common word game involving an exchange of words that are associated together. The game is based on the noun phrase **word association**, meaning \"stimulation of an associative pattern by a word\" or \"the connection and production of other words in response to a given word, done spontaneously as a game, creative technique, or in a psychiatric evaluation Psychophysical Testing Methods /Psychophysics - directly assess our perception of stimuli in relation to their true physical properties. **Psychophysics** quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they affect. Psychophysics has been described as \"the scientific study of the relation between stimulus and sensation\" or, more completely, as \"the analysis of perceptual processes by studying the effect on a subject\'s experience or behaviour of systematically varying the properties of a stimulus along one or more physical dimensions\". o **Methods of Limits**- In the ascending method of limits, some property of the stimulus starts out at a level so low that the stimulus could not be detected, then this level is gradually increased until the participant reports that they are aware of it. For example, if the experiment is testing the minimum amplitude of sound that can be detected, the sound begins too quietly to be perceived, and is made gradually louder. In the descending method of limits, this is reversed. In each case, the threshold is considered to be the level of the stimulus property at which the stimuli are just detected. 325 § In experiments, the ascending and descending methods are used alternately and the thresholds are averaged. A possible disadvantage of these methods is that the subject may become accustomed to reporting that they perceive a stimulus and may continue reporting the same way even beyond the threshold (the error of habituation). Conversely, the subject may also anticipate that the stimulus is about to become detectable or undetectable and may make a premature judgment (the error of anticipation). o **Method of Constant Stimulation**- Instead of being presented in ascending or descending order, in the method of constant stimuli the levels of a certain property of the stimulus are not related from one trial to the next, but presented randomly. This prevents the subject from being able to predict the level of the next stimulus, and therefore reduces errors of habituation and expectation. For \'absolute thresholds\' again the subject reports whether he or she is able to detect the stimulus. For \'difference thresholds\' there has to be a constant comparison stimulus with each of the varied levels. o **Method of Adjustment- method of average error -** The method of adjustment asks the subject to control the level of the stimulus, instructs them to alter it until it is just barely detectable against the background noise, or is the same as the level of another stimulus. This is repeated many times. This is also called the method of average error. In this method the observer himself controls the magnitude of the variable stimulus beginning with a variable that is distinctly greater or lesser than a standard one and he varies it until he is satisfied by the subjectivity of two. The difference between the variable stimuli and the standard one is recorded after each adjustment and the error is tabulated for a considerable series. At the end mean is calculated giving the average error which can be taken as the measure of sensitivity. Practice effects are considered a common subtype of order effects. Practice effects can be defined as influences on performance that arises from a practicing a task (Heiman, 2002). Even after practice trials are performed in/for a study, participants have a tendency to perform initial trials poorly because they are still not warmed up to it (Heiman, 2002). Performance can, however, improve after more trials are conducted because this allows participants to become more accurate and a lot quicker. Participants\' performance may decrease again, however, because they do have a tendency to become bored and/or fatigued after a while. \"An order effect is an influence on a particular trial that arises from its position in a sequence of trials\" (Heiman, 2002). Usually when one provides a series of questions for participants in a study, they run at risk for having an order effect. *Practice effects* usually occur when the participants find the questions to be either novel or have great reactivity. However, if there is a long list of questions, an increase in boredom is most likely to occur (Heiman, 2002). The same occurs for *carry-over effects*, when participants respond in a more biased manner to later questions because of any earlier 326 questions. *Response sets* can also occur over repeated closed-ended questions (Heiman, 2002). https://en.wikipedia.org/wiki/Sound\_localization The interaural time difference describes the difference in time it takes a sound to reach the left vs the right ear. The interaural level difference describes the difference in sound pressure level between the ears. The head dampens the overall sound to the far ear and reduces the intensity of the high frequency tones, but not the low frequency tones. **All of the points on the cone of confusion have the same interaural level difference and** **interaural time difference.** The neurotransmitter, GABA, works as the primary inhibitory neurotransmitter. Dopamine has many functions but is most often associated with reward, learning, and attention. Serotonin also has many functions but is most often associated with mood, appetite, social behavior, and memory. **The primary role of hypocritin also called orexin in the CNS is to control sleep and** **arousal.** **Temporal Monotocity:** Temporal monotonicity assumes that adding pain at the end of a painful experience (in this case extending the painful experience) will worsen the retrospective evaluation of the experienced pain and adding pleasure at the end will enhance the retrospective evaluation. Posner and Snyder described an action as automatic if the action did not affect other mental activities. The buildup of acetaldehyde causes symptoms such as nausea, headache, flushing of the face, and internal organ damage. Glutamate is associated with increased cortical arousal. Excessive sleepiness, which can be caused by a large sleep debt, is a consequence of the accumulation of adenosine. Cells responsible for arousal are inhibited by adenosine monophosphate (AMP). Phosphodiesterase decomposes cAMP into AMP. 327 **Caffeine inhibits an enzyme that breaks down cyclic adenosine monophosphate (cAMP). The** **increase in cAMP increases glutamate production. This increase in cellular activity results in** **action potentials that are briefer and released in bursts. (just remember cAMP =** **ON/SIGNALLING). Broken by phospodiester to AMP (a nucleotide)** Most perception of warmth occurs the insula. (Acronym: Warm is insulated) The cingulate cortex may be important in the perception of annoyance.(acronym: Sad Single Collosal) Spreading activation finds the shortest circuit. Asymmetry occurs because of STDP (Spike Time Dependent Plasticity); the synapse that fires regularly is strengthened in that direction, while the other synapse direction is weakened. Functional neuroimaging, one type of \'brain scanning\', involves the measurement of brain activity. The specific technique used to measure brain activity depends on the imaging technology being used (see fMRI and PET for examples). Regardless of which technology is used, the scanner produces a \'map\' of the area being scanned that is represented as voxels. Each voxel typically represents the activity of a particular coordinate in three-dimensional space. The exact size of a voxel will vary depending on the technology used, although fMRI voxels typically represent a volume of 27 mm3 (a cube with 3mm length sides). Anomia is a form of aphasia identified by the inability to name everyday objects. Agraphia is a form of aphasia characterized by the loss of the ability to form graphemes, which causes a loss in the ability to communicate via writing. § **The McGurk effect** is a categorical change in auditory perception that occurs whenever the auditory stimulus does not match the visual stimulus during speech perception. § **Melodic Intonation Therapy (MIT).** MIT works best with non-fluent forms of aphasia. § Receptive aphasia is a fluent aphasia. A person will be able to read or hear; however, she will be unable to understand the meaning of the communication. = Wernicke's aphasia is a fluent aphasia. The person will be able to produce language; however, the words will come out as 'word salad' or fluently connected speech that lacks meaning. § A global aphasia is often the result of damage to a large portion of the left hemisphere. This person will have difficulty producing speech, understanding speech, and will likely be unable to read or write. 328 § Broca's aphasia is a non-fluent form of aphasia. A person with Broca's aphasia will be unable to produce speech, but will be able to understand verbal speech. Risk factor vs protective factors Next Step Notes: https://www.youtube.com/watch?v=B2-TKZnq7fk **Mediating Variable:** A mediating variable specifies a given cause (original predictor variable, independent variable) that works indirectly through a more direct cause (mediator variable) to a final effect (outcome variable, dependent variable). The mediator adds to the overall variance accounted for in the data and can explain how the dependent and independent variables are related. A mediating variable is one which explains the relationship between two other variables. "RELATIONSHIP between two variables" EXPLAINS WHY OR HOW the relationship o **Explains the relationship between IV and DV** o **IV accounts for variations in DV** o **IV variations account for variations in mediator** o **Mediator variation account for variations in DV** o **When mediator is added to the mode, the relationship between the IV and DV** **decreases** **Moderating Variable:** A moderating variable is a variable that specifies conditions under which a given predictor is related to an outcome. The moderator explains 'when' a dependent and independent variable are related. A moderator variable is one that influences the strength of a relationship between two other variables. o **Changing the strength or direction of the relationship between IV and DV** o **Does not explain why there is a relationship between IV and DV** **Confounding Variable**: A confounding variable is a hypothetical or real third variable that is often not taken into account during analysis and can adversely affect the study. : A confounding variable is one which is not typically of interest to the researcher but is an extraneous variable which is related to BOTH the dependent and independent variables. o **IV is not CAUSING the confounding variable is the difference between a** **COUNFINDING VARIABLE and a MEDIATING VARIABLE (In a mediating variable** **the mediating variable CAUSES a confounding variable).** 329 **Heterophily** is the tendency of individuals to collect in diverse groups; it is the opposite of homophily. is correct. GABA is the chief inhibitory neurotransmitter in the CNS. It plays the principal role in reducing neuronal excitability throughout the nervous system and is found in decreased levels in patients with anxiety disorders. There are three basic molecules, known chemically as monoamines, which are thought to play a role in mood regulation: norepinephrine, serotonin and dopamine. The hypothalamus uses these neurotransmitters as it manages the endocrine system. The amygdalae are golf ball shaped groups of nuclei located within the temporal lobes of the brain. They serve to assist in the processing of memory, decision-making, and emotional reactions. **Aversive conditioning** is a behavioral conditioning technique in which noxious stimuli are associated with undesirable or unwanted behavior that is to be modified or abolished. **Social cue** is a vocal or non-vocal suggestion, which can be positive or negative. These cues guide conversation and other social interactions. A few examples of social cues include: facial expression, tone of voice and body language. AAMC Additional: **Beck's Cognitive therapy** (**CT**) is a type of psychotherapy developed by American psychiatrist Aaron T. Beck. CT is one of the therapeutic approaches within the larger group of cognitive behavioral therapies (CBT) and was first expounded by Beck in the 1960s. Cognitive therapy is based on the cognitive model, which states that thoughts, feelings and behavior are all connected, and that individuals can move toward overcoming difficulties and meeting their goals **by identifying and changing unhelpful** **or inaccurate thinking, problematic behavior, and distressing emotional responses**. This involves the individual working collaboratively with the therapist to develop skills for testing and modifying beliefs, identifying distorted thinking, relating to others in different ways, and changing behavior **Opponent-process theory** is a psychological and neurological model that accounts for a wide range of behaviors, including color vision. The **diathesis--stress model** is a psychological theory that attempts to explain behavior as a predispositional vulnerability together with stress from life experiences. The termdiathesis derives from the Greek term (διάθεσις) for disposition, or vulnerability, and it can take the form of genetic, psychological, biological, or situational factors.\[1\] A large range of individual differences exist between persons in their vulnerability to the development of disorder.\[1\]\[2\] **Ethical Research**: requires that all participants voluntarily participate in the study. At any point, participants should be able to freely withdraw their participation and their data can then no longer be used. 330 **Socioeconomic Status**: defined as consisting of income (or wealth), educational attainment, and/or occupational status Socioeconomic Gradient: Refers to the negative coorelation between socioeconomic status and po **Ethnographic Research**: involves observing social interactions in real social settings. o **For example**: studying the experience of role strain through observation can increase our understanding of how physicians cope with the challenging demands of extending life with interventions while accepting the reality of death. o **Ethnography** (from Greek ἔθνος ethnos \"folk, people, nation\" and γράφω grapho \"I write\") is the systematic **study** of people and cultures. interventional experiment **Comparative Study/Research: Comparative research** According to D.E Sanga (2004) Cooperative research is a research methodology in the social sciences that aims to make comparisons across different countries or cultures. A major problem in comparative research is that the data sets in different countries may not use the same categories, or define categories differently (for example by using different definitions ofpoverty). **The Flynn effect** is an observation regarding the growth of IQ from one generation to the next. Emotional intelligence is the ability to understand emotions present in oneself and how those emotions motivate oneself and others. Median: less susceptible to variation (when compared to mode) Egoism: Egoism (also known as psychological egoism) is a philosophical concept in which the motivations and instincts for an individual\'s behavior are based on their own selfinterest and welfare. It is the belief that all of our behaviors and actions are based on the benefit that we will receive from it. This is contrasted with psychological altruism which proposes that some human actions are based on the desire to help other people. Read more: http://www.alleydog.com/glossary/definition.php?term=Egoism\#ixzz46lzvMk2G Prevalence Etiology Power Data stratification Cross's Nigrescence Model: o Pre-encounter o Encounter o Immersion/Emersion 331 o Internalization o Internalization-Commitment Conditioned memory is a type of memory that is formed based on your associations between two things. For example, if your professor rings a bell at the end of the exam, you will remember the bell as the sign that the exam is over. **Minority influence** occurs when a smaller group over time is able to persuade the majority to join their side. A type of social influence, this topic was researched in depth by Moscovici. Minority influence uses conversion as a means for the minority group to be influential- conversion is convincing someone who originally doesn\'t agree with your views that you are right. o Examples of minority influence include the Suffragette and Civil Rights movements in the United States. These originated within a smaller group who over time were able to convince the majority to sympathize and agree with their side. o When a new idea arises, it is automatically a minority opinion. This idea can then be spread through the influence of the minority on others accepting this view. **Multiple Approach-Avoidance** describes the internal mental debate (sometimes called a conflict) that weighs the pros and cons of differing situations that have both good and bad elements. The name comes from visualizing yourself approaching and avoiding different aspects of situations at the same time. o An example would be choosing between two different cars, each with differing pros and cons. One car gets great gas mileage and has lots of fancy stuff (approaching) but is very expensive and expensive to maintain (avoidance). The other car is cheap and cheap to maintain (approaching) but very boring and won\'t last long term (avoidance). Your mind will weigh these different options and eventually come to a decision based on the information you considered. As humans this is a very common internal debate that we use daily, from choosing what food to eat (healthy food vs. tasty junk food) to where we will live (country vs. city). **Approach-approach conflicts** two options are both appealing. **Avoidant-avoidant conflicts** both options are unappealing An **approach-avoidance conflict** is when one option has both aspects, but here there are two options. **Double approach-avoidant conflicts** consist of two options with both appealing and negative characteristics, which seemed to represent the jury's dilemma. If they ruled the defendant guilty, then they could be punishing a criminal(approach) or maybe punishing an innocent(avoidant). If they ruled the defendant innocent, then they would be letting a criminal walk away unpunished(avoidant) or freeing an innocent (approach). 332 Cialidini's Six key principles of influence 1\. **Reciprocity** -- People tend to return a favor, thus the pervasiveness of free samples in marketing. In his conferences, he often uses the example of Ethiopia providing thousands of dollars in humanitarian aid to Mexico just after the 1985 earthquake, despite Ethiopia suffering from a crippling famine and civil war at the time. Ethiopia had been reciprocating for the diplomatic support Mexico provided when Italy invaded Ethiopia in 1935. The good cop/bad cop strategy is also based on this principle. 2\. **Commitment and Consistency** -- If people commit, orally or in writing, to an idea or goal, they are more likely to honor that commitment because of establishing that idea or goal as being congruent with their self-image. Even if the original incentive or motivation is removed after they have already agreed, they will continue to honor the agreement. Cialdini notes Chinese brainwashing on American prisoners of war to rewrite their self-image and gain automatic unenforced compliance. Seecognitive dissonance. 3\. **Social Proof** -- People will do things that they see other people are doing. For example, in one experiment, one or more confederates would look up into the sky; bystanders would then look up into the sky to see what they were seeing. At one point this experiment aborted, as so many people were looking up that they stopped traffic. See conformity, and the Asch conformity experiments. 4\. **Authority** -- People will tend to obey authority figures, even if they are asked to perform objectionable acts. Cialdini cites incidents such as the Milgram experiments in the early 1960s and the My Lai massacre. 5\. **Liking** -- People are easily persuaded by other people that they like. Cialdini cites the marketing of Tupperware in what might now be called viral marketing. People were more likely to buy if they liked the person selling it to them. Some of the many biases favoring more attractive people are discussed. See physical attractiveness stereotype. 6\. **Scarcity** -- Perceived scarcity will generate demand. For example, saying offers are available for a \"limited time only\" encourages sales. 1\. While conveying scarcity, in general, can influence others, in the case of an opinion, the more people that agree, the more likely others are to follow, so scarcity is not desirable. Spatial Discrimination- The ability to perceive as separate points of contact the two blunt points of a compass w hen applied to the skin.