Listen to the audio lecture while viewing these slides or view the video presentations available through Blackboard Psychology 372 Physiological Psychology Steven E. Meier, Ph.D. 1 Sensory Systems

Psyc 372 – Physiological Psychology 2 Overview Lots of sensation or sensory systems Whole fields of Psychology are associated with this area Examples Visual system Auditory system Tactile system Olfactory and Taste system others

Psyc 372 – Physiological Psychology Systems overview Systems have some type of receptor system Receptor systems are designed to convert some outside stimulus to a electrical-chemical signal Is called transduction The electrical-chemical signal is used by the nervous system 3

Psyc 372 – Physiological Psychology Receptor systems Usually lack axons Usually form synapses with dendrites of other sensory neurons Messages are carried on different pathways to specific areas of the brain Detect small ranges of energy levels Visual system: 400 to 700 nm Auditory system: 20 to 20,000 Hz 4

Psyc 372 – Physiological Psychology Receptor systems Some systems are more complicated than others Visual system versus touch system Visual system was initially part of brain systems Has become more specialized and moved Allows more processing of information Increases survival. 5

Psyc 372 – Physiological Psychology The Eye 6

Psyc 372 – Physiological Psychology Some structures Pupil: Is basically a hole Iris: Is a muscle that controls the size of the hole Cornea: Is it clear transparent membrane that covers the pupil and Iris Focuses approximately 75% of visual information onto the retina Lens: Focuses the remaining 25% of light onto the fovea of the retina 7

Copyright 2001 by Allyn & Bacon Rods and Cones n Two types of photoreceptors are located within the retina l Rods: 120 million u Light sensitive (not color) u Found in periphery of retina u Low activation threshold l Cones: 6 million u Are color sensitive u Found mostly in fovea Source: /imageswv/rodcoEM.jpeg 6.8

Copyright 2001 by Allyn & Bacon Retinal Circuitry 6.9 Adapted from Dowling, J.E., and Boycott, B.B. Proceedings of the Royal Society of London, B., 1966, 166,

Copyright 2001 by Allyn & Bacon Primary Visual Pathway n Information from each visual field crosses over at the optic chiasm and projects to the opposite side of the primary visual cortex 6.10

Copyright 2001 by Allyn & Bacon Visual Cortex 6.11

Copyright 2001 by Allyn & Bacon Summary of Visual Cortex n V4: responds to color (and form perception) u Lesions of V4 impair color perception n V5: responds to movement n TEO: involved in color discrimination, 2-d pattern discrimination u TEO projects to area TE n TE: neurons here respond to 3-d objects (a face or a hand) 6.12

Psyc 372 – Physiological Psychology Auditory system Is less sophisticated than the visual system Designed to transduce frequencies of sound into hearing 13

Psyc 372 – Physiological Psychology Divisions of the Ear Outer ear: Channel to tympanic membrane Middle ear: Ossicles Inner ear: Cochlea

Psyc 372 – Physiological Psychology The Cochlea The cochlea is formed from three chambers: Hair cells within the organ of Corti transduce sound waves into nerve impulses 7.15

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Psyc 372 – Physiological Psychology Auditory Pathways Afferent pathways: Through cochlear nuclei To superior olivary nuclei To inferior colliculus To medial geniculate To auditory cortex Efferent pathway: Olivocochlear bundle 7.17

Psyc 372 – Physiological Psychology Touch / Pain Three different sensations are reported to the brain by receptors localized within skin 7.18

Psyc 372 – Physiological Psychology Temperature Is detected by warmth and cold receptors Receptor activation is relative to the baseline temperature The receptors lie at different levels of the skin (cold are close to the surface of the skin) 19

Psyc 372 – Physiological Psychology Touch and Pain Touch involves perception of pressure and vibration of an object on the skin Pacinian corpuscles detect deformation of the skin Pain is associated with skin tissue damage Nociceptors detect pain 20

Psyc 372 – Physiological Psychology Morphology of Skin 7.21 Dermis Epidermis

Psyc 372 – Physiological Psychology The dorsal columns carry precise information related to touch The spinothalamic tract carries pain and temperature signals (poorly localized) 5-10 cortical maps of the body surface Somatosensory Pathways 7.22

Psyc 372 – Physiological Psychology Other systems Taste Vestibular 23

Psyc 372 – Physiological Psychology Conclusions Lots of systems Each has a specific purpose When damage occurs, usually multiple systems are impacted. Creates specific symptomatology Can be used to identify locations of brain or system damage 24