Sensory Systems Lesson 14

Sensory Information n 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 ~

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

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

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

Sensory Information: 4 types n 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 ~

Cortical Organization n Topographic l area in receptive field l mapped onto cortex n Examples l cochlea  A1 l retina  V1 l dermatomes  S1 ~

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

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

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

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

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