Chapter 15: Schizophrenia 1. What types of symptoms characterize schizophrenia? Is schizophrenia the same as multiple personality disorder?-There are both positive symptoms and negative symptoms of schizophrenia;it can be characterized by the presence of 2 with in a 1 month period.- Positive Symptoms-things added to the environment/behaviors that are present that should be absent.o Delusions-unjustified beliefso Hallucinations- false sensory experiences/ perceptionso Disorganized Speecho Disorganized psychomotor behavior, including catatonia- Negative Symptoms-things absent from environment/behaviors thatare absent that should be present. i.e. flattened affect, decreased motivation, and social withdrawal.- Cognitive Symptoms-difficulty understanding abstract concepts and deficits in working memory. (not part of diagnostic criteria but may be a central symptom that leads to other symptoms)- Schizophrenia is NOT the same as multiple personality disorder. It means split mind but meant to represent split from reality.2. What are some predictors or correlates of schizophrenia?-There is a relatively high (but not complete) degree of heritability in increase in biological relatedness=an increased risk. The environment also plays a large role. Schizophrenia is more prevalent in major cities than in rural areas and in more developed compared to developing countries. People with schizophrenia have impairments in attention and working memory and deficits in pursuit-based-eye-movements. Schizophrenia is also more common in men than in women.3. Describe the how the prenatal and neonatal environment has been shown to be linked to the development of schizophrenia. What types of brain abnormalities seen in schizophrenia are consistent with the neurodevelopmental hypothesis?- Schizophrenia is more common in individuals who had complications during birth. Rh incompatibility of mother and fetus also places a role in schizophrenia. An Rh-positive blood factor of fetus can trigger an immune response of Rh-negative mom, this increases across multiple pregnancies. There is also the Season-of-birth effect. People born in winter have increased chance of schizophrenia this may be due to flu virus and or nutritional deficiencies. It is also more common in children with older fathers and is associated with head injuries in childhood. Lastly, there is an increased prevalence in people who had childhood infections especially of Toxoplasma gondii (found in cats). As a result of these factors people with schizophrenia tend to have decreased brain volume and smaller cell bodies in brains, especially in those regions that take a long time to develop.4. What roles do dopamine and glutamate play in the cause and treatment of schizophrenia?-People with schizophrenia do not have more brain dopamine, but their neurons release it faster and they do have higher concentrations of dopaminereceptors and also people with schizophrenia have lower than normal release of brain glutamate and fewer glutamate receptors. In many areas dopamine inhibits glutamate release or glutamate stimulates neurons that inhibit dopamine release. Therefore the effects of increasing dopamine are similar to those of decreasing glutamate. Most antipsychotic drugs block dopamine receptors and activity at dopamine synapses in order to deal with this problem.5. What side effects do old antipsychotic drugs cause that are not seen in the use of new atypical antipsychotics? -Old antipsychotic drugs caused Parkinson’s-like motor side effects and usually only eliminated positive symptoms. New atypical antipsychotic drugsdo bot cause these side effects and are more effective at treating negative symptoms. Chapter 6: Vision1. What does perception depend on? Describe the general path that stimulus energy takes through our brain, leading to conscious perception.-Perception depends on what types of receptors are stimulated (law of specific nerve energies), how many/ how much they are stimulated, in what pattern they are stimulated, and what neurons those sensory neurons projectto. Stimulus energy travels through receptors on sensory neurons (retinal photoreceptors) to a nerve to the CNS (optic nerve) to the thalamus (lateral geniculate nucleus) to the Primary cortex and the finally to the association cortex leading to conscious perception.2. How does light enter the eye? Describe the path it takes through the cell layers of the retina.–Photons of light enter the eye through the pupil. It is focused by cornea and lens to the retina at the back of the eye. The position of the image then becomes inverted.3. How are rods and cones similar and different? On what point of the retina are cones most densely packed? With which types of cells do photoreceptorssynapse? Do they excite or inhibit those cells?- Rods- respond well to faint light; over stimulated by bright light, abundant in periphery, necessary for black and white vision- Cones-need bright light to respond but provide more detailed info butprovide more detailed info, abundant in center especially fovea, whichis a depression in the retina where light hits unimpeded by other cells,essential for color vision-contain special photo pigments- Photoreceptors-synapse with bipolar cells and disinhibit them, they also synapse with horizontal cells and excite them. 4. Describe how lateral disinhibition of bipolar cells results in center-surround receptive fields of ganglion cells.-Lateral inhibition is the activity of a neuron decreases the activity of its neighboring neurons, this is important for light-dark border/ contrast.Lateral inhibition results in bipolar cells sending information to ganglion cells in a disturbed manner, signals from the middle of the area that light strikes are the strongest and signals from areas in the very center and edge less strong. The result is ganglion cells have donut shaped receptive fields in that they respond to areas of the visual space in a center-surround manner. 5. On what is our perception of color based? What happens when the same photo pigment is produced in two different types of cones?-Our perception is based on the wavelength with which photons hit receptors, our perception or relative color is based on the relative rates of responding to certain ranges of wavelength. One experiences color deficiencyor color blindness when the same photo pigment is produced in two differenttypes of cones.Vision 2:1. Describe the path of the optic nerve – which and where
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