Psyc 372 – Physiological Psychology Overview • Lots of sensation or sensory systems • Whole fields of Psychology are associated with Sensory Systems this area • Examples • Visual system Psychology 372 • Auditory system • Tactile system Physiological Psychology • Olfactory and Taste system Steven E. Meier, Ph.D. • others Listen to the audio lecture while viewing these slides or view the video presentations available through Blackboard 1 2 Psyc 372 – Physiological Psychology Psyc 372 – Physiological Psychology Systems overview Receptor systems • Systems have some type of receptor • Usually lack axons system • Usually form synapses with dendrites of • Receptor systems are designed to other sensory neurons convert some outside stimulus to a • Messages are carried on different electrical-chemical signal pathways to specific areas of the brain • Is called transduction • Detect small ranges of energy levels • The electrical-chemical signal is used by • Visual system: 400 to 700 nm the nervous system • Auditory system: 20 to 20,000 Hz 3 4 Psyc 372 – Physiological Psychology Psyc 372 – Physiological Psychology Receptor systems The Eye • 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 6 1 Psyc 372 – Physiological Psychology Rods and Cones Some structures Two types of photoreceptors are • Pupil: Is basically a hole located within the retina • Iris: Is a muscle that controls the size Rods: 120 million Light sensitive (not color) of the hole Found in periphery of retina • Cornea: Low activation threshold • Is it clear transparent membrane that Cones: 6 million Are color sensitive covers the pupil and Iris Found mostly in fovea • Focuses approximately 75% of visual information onto the retina • Lens: Focuses the remaining 25% of Source: http://insight.med.utah.edu/Webvision /imageswv/rodcoEM.jpeg 6.8 light onto the fovea of the retina 7 Copyright 2001 by Allyn & Bacon Retinal Circuitry Primary Visual Pathway Information from each visual field crosses over at the optic chiasm and projects to the opposite side of the primary visual cortex Adapted from Dowling, J.E., and Boycott, B.B. Proceedings of the Royal Society of London, B., 1966, 166, 80-111. 6.9 6.10 Copyright 2001 by Allyn & Bacon Copyright 2001 by Allyn & Bacon Visual Cortex Summary of Visual Cortex V4: responds to color (and form perception) Lesions of V4 impair color perception V5: responds to movement TEO: involved in color discrimination, 2-d pattern discrimination TEO projects to area TE TE: neurons here respond to 3-d objects (a face or a hand) 6.11 6.12 Copyright 2001 by Allyn & Bacon Copyright 2001 by Allyn & Bacon 2 Psyc 372 – Physiological Psychology Psyc 372 – PhysiologicalDivisions Psychology of the Ear Auditory system • Is less sophisticated than the visual • Outer ear: system • Channel to • Designed to transduce frequencies of tympanic membrane sound into hearing • Middle ear: • Ossicles • Inner ear: • Cochlea 13 Psyc 372 – Physiological Psychology 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 16 Psyc 372 – PhysiologicalAuditory Psychology Pathways Psyc 372 – Physiological Psychology Touch / Pain • Afferent pathways: • Three different sensations are reported • Through cochlear nuclei to the brain by receptors localized within skin • To superior olivary nuclei • To inferior colliculus • To medial geniculate • To auditory cortex • Efferent pathway: • Olivocochlear bundle 7.17 7.18 3 Psyc 372 – Physiological Psychology Psyc 372 – Physiological Psychology Temperature Touch and Pain • Is detected by warmth and cold • Touch involves perception of pressure receptors and vibration of an object on the skin • Receptor activation is relative to the • Pacinian corpuscles detect deformation baseline temperature of the skin • The receptors lie at different levels of • Pain is associated with skin tissue the skin (cold are close to the surface of damage the skin) • Nociceptors detect pain 19 20 Psyc 372 – PhysiologicalMorphology Psychology of Skin Psyc 372 – Physiological Psychology Somatosensory Pathways • The dorsal columns carry precise information related to Epidermis touch • The spinothalamic tract carries pain and Dermis temperature signals (poorly localized) • 5-10 cortical maps of the body surface 7.21 7.22 Psyc 372 – Physiological Psychology Psyc 372 – Physiological Psychology Other systems Conclusions • Taste • Lots of systems • Vestibular • 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 23 24 4.