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PSY 201 1st EditionExam # 2 Study Guide Lectures: 6-9Highlight=important termsLecture 6 (1/22)What happened in the movie ‘Brain Transplant’? Was the operation performed on the two patients successful? What are the symptoms of Parkinson’s, and what brain systems are involved? What is the brain’s ability to repair damage? What is MPTP and what were its effects?What is involved in a tissue transplant?The in-class movie ‘Brain Transplant’ surrounded a problem discovered circa 1970’s-1980’s in which a number of people were found incapable of movement in their homes and apartments. This change was sudden an inexplicable. It was discovered that these people’s brains were fully functioning (they could understand speech, write what they were thinking, etc.) but their bodieswere unmovable. The cause of this was determined to be a bad batch of synthetic heroin created by a drug dealerin an underground lab. The man accidentally created a chemical called MCTP: a chemical (very similar to heroin) that produced effects such as paralysis and Parkinson-like symptoms. When this was discovered, the patients were given Eldopa, a drug that is used to treat Parkinson’s in elderly patients.At first the results were astounding; the patients drastically improved. Later, however, the drug caused them side effects that were also similar to Parkinson’s. Their symptoms included uncontrollable twitching, rigidity of movement, limited ability to walk and occasionally back to paralysis. This involves a degeneration of the Substantia Nigra cells; nuclei located in the midbrain containing dopamine receptors and projecting to Basal ganglia. It was decided that another method was needed to help these patients with their condition.A method for surgery was devised with the help of a science team in Sweden. It was discovered that scientists could use stem cells (from the brains of aborted fetuses) and inject them into the brains of the patients; a kind of tissue transplant. Since the brain has a limited ability to repair damaged cells, this method seemed like the best method.Two patients were selected as being optimal candidates for the surgery (one male and one female). The surgery was not an immediate success; it took approximately two years for there to be any sign of substantial recovery. Once that time had passed, however, the patients showedremarkable advancements in walking, speaking and controlling their movements.Lecture 7 (1/27)(This combines some material begun in lecture 6 but concluded in lecture 7)Define sensation and perception. What are all the human senses? Define receptors, sensory neurons, sensory areas and transduction. What is the coding of stimulus quality and quantity? How is the eye constructed like a camera? What are the parts and cells of the retina? Define rods and cones. How do light waves determine how we process color? Name the visual pathways and contralateral connections. Explain the coding of contrast and contours, and the neural basis for these effects. Define feature detection and functional specialization. What are the problems caused by temporal/parietal lobe lesions?Sensation: defined as the initial coding of messages from the sensesPerception: defined as the interpretation of the messages from the senses, and is a continuous process (the transformation of incoming signals into information about the world)Senses- Vision (sensing light waves)- Smell (chemicals in the air)- Hearing (vibrations in the air)- Touch (deformation or discrepancy)- Taste (chemicals in food)- Vestibular sense (balance, gravity and motion)- Kinesthesis (limb position and movement, muscle stretch and joint angles)- Temperature (changes in temperature)- Pain (pain receptors)Receptors: produce electrical changes in response to a physical stimulus that initiate neural impulses, and react directly to environmental stimuliSensory neurons: responsible for carrying neural impulses from the receptor to the Central Nervous SystemSensory areas: the location that the sensory neurons carry neural impulses toTransduction: conversion of energy from a physical stimulus into neural responses (the way in which receptors work)Stimulus coding- Describes the representation of the stimulus in the pattern of action potentialso Stronger stimulus: greater quantity of electrical changes in the receptors (leadingto faster action potential firing rate)o Different receptors respond to different forms of energy (retinal receptors respond to light, touch receptors to pressure), known as the coding of qualityConstruction of the eye- The eye is constructed like a camerao The cornea and the lens concentrate on the outside points of an object and focusit onto the retina (in the back of the eye) where photoreceptors respond to lighto The fovea is the area of the retina where receptor cells are densely packed, and iswhere the best and most detailed vision occurs The location where the optic nerve leaves the eye is the blind spot, wherethere are no receptors- Parts of the retinao Rods and cones (receptor cells) Rods: located on the outside of the fovea, and are sensitive to light but not color (operate under low light conditions) Cones: located inside the fovea, and are less sensitive to light (operate under high light conditions)Light wavesWavelength determines a color and the amplitude determines the brightnessVisual pathways- Begins with the optic nerve: the way through which cells leave the eyeo Optic chiasm: where the nasal ganglion cell axons cross to the other side of the brain (temporal ganglion cell axons stay on the same side of the brain)o These cells project to the Lateral Geniculate Nucleus (LGN) and then to the primary visual cortex- Contralateral connections: the nasal ganglion cells cross at the optic chiasm whereas temporal cells stay on the same sideCoding of contrast and contours- Objects are defined by contours and boundaries, which are defined by contrasts on the sides of boundaries- Retinal ganglion and LGN cells have ‘on’ and ‘off’ field organizationo ‘On’: light increases activity from a spontaneous rateo ‘Off’: light decreases activity from spontaneous rate Best stimulus: spot of light or an edge Worst stimulus: uniform illumination Lateral inhibition: receptor cells send projections to bipolar cells- A spot of light in the middle increases the firing rate- Receptors project to horizontal cell (with inhibitory synaptic effect)o Causes another increase in firing


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