1. Sensory Systems Lecture 12

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

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

4. Sensory Receptors • Specialized cells • similar properties to neurons • Transduction • environmental energy  neural signal • receptor potential ~

5. Sensory Receptors • Mechanoreceptors • auditory, somatosensory • Chemoreceptors • taste, smell • Photoreceptors • vision • Thermoceptors • hot, cold ~

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

7. Cortical Organization • Topographic • area in receptive field • mapped onto cortex • Examples • cochlea  A1 • retina  V1 • dermatomes  S1 ~

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

9. Sensory Modalities • Auditory • timbre • pitch • Vision • color • shape • motion ~

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

11. Sensory Modalities: Somatosensation • Primarily mechanoreceptors • Touch • pressure, vibration • Kinesthesis • body position & movement ~

12. Sensory Modalities: Somatosensation • Pain (stretch receptors) • itch (chemoreceptors) • temperature (thermoreceptors) • Haptic System • touch & kinethesis