EXP 3202 Sensation and Perception Exam 1 Notes Study Guide History The role of the brain in perception Some people think the heart is the organ with which we think and that it feels pain and anxiety Hippocrates Sensation Perception and the Brain History of Medical and Philosophical Ideas Ancient teachings o Hippocrates 460 377 The brain is key Probably from brain damaged o Plato 428 347 Brain is roughly spherical so appropriate for seat of reason o Aristotle 384 322 Brain s function was to cool off the heart cardiocentric patients view o Galen 129 200CE Ventricles of the brain Dualism o Descartes behavior could be controlled by sensory motor reflexes Physical world Sensory organs Action Muscles Pineal Brain gland Mind o Physical world sensory organs brain pineal gland mind muscles action Involuntary action sensory motor reflex Perception conscious action controlled by the mind o Non physical world the mind o Dualism allows clear division of Sensation and Perception Materialism Monism o Thomas Hobbes a man is a body substance and body signify the same thing and therefore substance incorporeal are words which when they are joined together destroy one another Perception is not in the object but in us i e sound is in us vision is in us Importance of science Men are different from animals because we care about knowing causes and why things are happening intellectual curiosity want to know the answer o Definition of Empiricism all knowledge comes from experience i e sensation Ideas associations of sensations and or perceptions Empiricism o John Locke and the British Empiricists Tabula rasa blank slate and perception Functionalism Evolutionary perspective o Darwin Continuity of species Natural selection 2 important features o 1 Variation in the trait o 2 Selection Reproduction not survival per se Darwin s influence Continuity of species can study animals to learn about human Change of focus from Structuralism content of the mind e g mechanisms o Conservation of a trait Locke to Functionalism o Evolutionary perspective o Perception and our sense of reality are the products of evolution Reproductive success Importance of type of energy in the environment determines o Adaptive value sensory processes are specialized for the ecological niche Divergence Diversification of traits Some species sense energies that humans cannot Bees see ultraviolet lights Rattlesnakes sense infrared energy Dogs and cats can sense sounds with higher frequencies Sensory systems and neurobiology o Sensory transduction is a biological process o Materialist perspective perception also a biological process Brain activity related to perception What we experience is the activity of nerves Doctrine of specific nerve energies Awareness related to WHICH nerves are activated not HOW they are activated Neuroscience Gross anatomy o Basic terminology Different orientations views of the Brain Dorsal view top Lateral view side Ventral view bottom Lobes of the brain frontal parietal temporal occipital Cuts of the brain Horizontal cut Coronal cut o rostral to caudal cut parallel to the ground o perpendicular to the ground and middle o Cut from dorsal to ventral surface Sagittal cut Parts of brain o Cut down midline perpendicular to the ground Brain stem where information first enters the synapse Midbrain after brain stem important for orientation in world around us Cerebellum movement some learning Thalamus important part of the forebrain place where there is initial processing before going to the cortex Cerebral cortex Corpus collosum fiber tracks connecting one side of the hemisphere to the other side o Typical Ascending Organization Receptor brain stem midbrain thalamus cortex Sensory inputs to the brain cord o Sensory information enters the brain through the CRANIAL NERVES or spinal Cranial nerves twelve pairs of nerves one for each side of the body that originate in the brain stem and reach sense organs and muscles through openings in the skull General flow of information How neurons work o Electrical Actvity in Neurons is IONIC o ION molecule having fewer more electrons than protons They have an electrical charge o Example Salt socium chloride NaCL When dissolved NA and CL o Electical Activity in Neurons is IONIC o Electrical event requires a battery or the equivalent o In a sense the neuron is a small rechargeable battery o Ions to know Sodium Na Chloride Cl Potassium K Calcium Ca Anion any ion with charge Cation any ion with charge Ions and their distributions o Unequal distribution of ions electrical charge across membrane i e the membrane is polarized it has a resting potential o Electrical activity of neurons ions move across the membrane Channels o Channels allow ions through the membrane o Are proteins embedded in the lipid fat membrane o Are classified by What opens gates them What ions they let through o An action potential starts with voltage gated Na channels open The action potential Systematic communication Psychophysics Psychometric Functions plot of observation response as physics stimulus changes o How do we measure something as personal as a perception o Psychophysics study of the changes in reported perception psycho as a function of the changes in the physical stimulus physics Main Issues o Detection minimum intensity we can perceive Determining the absolute threshold Lowest level of stimulus that you can detect Vary intensity of physical stimulus and measure yes no response Systematic Methods Method of Limits o Gradually descending or ascending series of intensity steps down usually gives lower threshold than up Method of Constant Stimuli o Various fixed levels presented in random order each presented a number of times Method of Adjustment o Subject adjusts up and down to just detectible level In all variability in threshold Why o Signal detection theory Methodology Signal Detection Theory model for how people make decision Near threshold there is some guessing variation in response strategies bias o Likelihood of saying yes when uncertain How can you tell if subject is guessing o Catch trials no stimulus presented o Discrimination ability to detect differences in similar stimuli o Scaling intensity of the sensation o Identification Context placing a learned label on a particular sensation Essay question answer de polarization Once axon enters the vesicle lets in the positively charged ions that causes Every bio active drug Synapse Neurotransmitter does not enter postsynaptic membrane to cause
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