Sensory Systems Lesson 14 Sensory Information Detection of

Sensory Systems Lesson 14

Sensory Information Detection of changes in environment l external or internal n 4 main functions l perception l control of movement l regulation of body function l maintenance of arousal n Not all conscious experience ~ n

Sensation vs. Perception Sensation l detection of stimulus l 1 st interaction with NS l filtering n Perception l integrated of information l selected, organized & interpreted n Different perceptions of same event ~ n

Sensory Receptors Specialized cells l similar properties to neurons n Transduction l environmental energy neural signal l receptor potential ~ n

Sensory Receptors Mechanoreceptors l auditory, somatosensory n Chemoreceptors l taste, smell n Photoreceptors l vision n Thermoceptors l hot, cold ~ n

Sensory Information: 4 types Modality l visual vs. pain vs. auditory, etc. l Doctrine of specific nerve energies n Intensity l frequency code n Duration l fast & slow adapting receptors n Location l receptive fields ~ n

Cortical Organization Topographic l area in receptive field l mapped onto cortex n Examples l cochlea A 1 l retina V 1 l dermatomes S 1 ~ n

Organization of Pathways Hierarchical (serial) l receptor 1 st order neuron higher order neuron l levels: different processing function n Parallel (simultaneous) l different submodalities n ucolor vs. monochrome vision upain vs. touch l converge at higher cortical levels ~

Sensory Modalities Auditory l timbre l pitch n Vision l color l shape l motion ~ n

Sensory Modalities Chemical senses l Gustatory – taste l Olfactory - smell n Orienting senses l vestibular system l head orientation, rotation, balance l mechanoreceptors in middle ear ~ n

Sensory Modalities: Somatosensation Primarily mechanoreceptors n Touch l pressure, vibration n Kinesthesis l body position & movement ~ n

Sensory Modalities: Somatosensation Pain (stretch receptors) l itch (chemoreceptors) l temperature (thermoreceptors) n Haptic System l touch & kinethesis n