PSYC 101 1st Edition Lecture 18 Outline of Last Lecture II. Stress & Drug Use Continued A. HumansB. Early Stress III. Now What? IV. Minimizing Stress a. Social Stressb. Exercise c. Healthy DietV. Sensation & Perceptiona. Sensationb. Perception Outline of Current Lecture VI. Sensation & Perception a. Top-Down Processingb. Bottom-Up ProcessingVII. Visiona. Eye Componentsi. Corneaii. Pupiliii. Irisiv. Lensv. Retinavi. Foveavii. Blind Spotviii. Pigment Epithelium b.Photoreceptorsi.Conesii.RodsVIII.Level of ProcessingIX. Color Vision a. Trichromatic VisionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Opponent-Process TheoryCurrent Lecture: Sensation and Perception ContinuedII. Sensation & Perception a. Top-Down Processing: bring experiencesb. Bottom-Up Processing: raw material c. Ex: See an black and white picture, with confusing shapes: i. Bottom-Up Processing: figuring out the image is a cowii. Top-Down Processing: anytime when viewing image again, regardless of time, always see the cow Vision: 60% of sensory neurons; Occipital Lobe – 100% visionWavelength energies course through body – brain only perceives a small portion of the worldIII. Visiona. Eye Componentsi. Cornea: outer most part of the eye, you can touchii. Pupil: letting light in – real bright, small pupil; dark, pupil gets larger in search for lightiii. Iris: the color area; muscle responsible for closing and opening pupils iv. Lens: behind pupil; amplifies light, shapes light, bends light; like any otherlensv. Retina: where vision happens – back of the eyeball; neurons responding to light, release neurotransmitters; basic shapes and colors (cones and rods)vi. Fovea: all detail vision occurs; information; .1% of the retina – point of central focus in the back of eye – images are projected upside down in retina and fovea vii. Blind Spot: cannot see; back of eye under fovea; blood vessels in through optic nerve. No photo receptors to pick up light, other eye covers for each other – if not, brain will make up imageviii. Pigment Epithelium: painted dark inside to absorb extra light; ex: light reflects off of white, so P.E. soaks up the extra reflections. Nocturnal animals do not have P.E. because they need to see at night, requiring use of all light; why some animals’ eyes glow at night Nearsighted: see objects up close – best focal point is before the retinaFarsighted: see objects far away – best focal point would ideally be behind the eyeb. Photoreceptors: located in the retina, millions of them, respond to lighti. Cones: 1. Color2. 6 million per eye3. Center, fovea 4. Not sensitive to dim light; requires a lot of light to function5. Sensitive to detail; foveaii. Rods1. No color2. 120 million per eye3. Periphery 4. Sensitive to dim light; does not require a lot of light5. Not detail sensitive Cones – Daytime: tell colors better; reading detail straight aheadRod – Nighttime: basic tendencies c. Levels of Processing: Rods & ConesBipolar CellsGanglion CellsOptic Nerve Optic Chiasm – where info crosses over – but only half vision field from each eye Thalamus (relay sensor) – can inhibit info before occipital lobe Visual Cortex (Occipital Lobe) – untangles crossover from optic chiasm Axons in eye are not myelinated – so vision is 1/10th of a second behindLight must travel through ganglion & bipolar cells to finally reach rods and cones for processingd. Color Vision i. Trichromatic Vision – there are 3 types of color receptors (cones) sensitiveto separate colors – red, blue, and green: some cones prefer certain colors (wave length of light) Color – wave length of light – no universal code saying 600 nanometers wave length is red – evolved meaning of wavelength 1. Color Blind – genetically missing certain cones; typically red or green2. Blue Cones – 400 wave preferred 3. Red Cones – 575-600 wave 4. Green Cones – 550-575 waveii. Opponent-Process Theory – opposing retinal processes (red-green, yellow-blue, white-black) enable color vision; ex: some cells stimulated bygreen and inhibited by red; vice
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