1. 1 Psychology 304: Brain and Behaviour Lecture 23

2. 2 Announcement The Psychology Department and Sociology Department are co-sponsoring a presentation by Dr. Philip Zimbardo, Professor Emeritus at Stanford University. The presentation will be held on: Friday, November 20 1:00-2:00 PM Frederic Wood Theatre, 6345 Crescent Road

3. 3 The Somatosensory System and the Auditory System 1. What are the major areas of the brain that are associated with the perception of touch? 2. What are the physical and perceptual dimensions of sound? 3. What is the structure of the ear and where are the receptors for sound?

4. 4 What are the major areas of the brain that are associated with the perception of touch? The majority of thalamic neurons that receive touch information subsequently project the information to the primary somatosensory cortex (SI). Thereafter, information is projected to the secondary somato- sensory cortex (SII) and the posterior parietal cortex.

5. 5 Primary Somatosensory Cortex (SI) Somatosensory Areas of the Brain Secondary Somatosensory Cortex (SII) Somatosensory Association Cortex

6. 6 SI is somatotropically organized—that is, organized according to a map of the body. The somatotropic map found in SI is referred to as the somatosenosry homunculus. The representation of the body in the somatosensory homunculus is distorted.

7. 7 The Primary Somatosensory Cortex

8. 8 The Nerve-Weighted Man

9. 9 What are the physical and perceptual dimensions of sound? Sounds are produced by objects that cause air molecules to vibrate. As they vibrate, the air molecules alternately condense and expand, producing sound waves. Sound waves vary on three physical dimensions. Each physical dimension uniquely influences our perception of sound.

10. 10 Physical and Perceptual Dimensions of Sound Waves

11. 11 What is the structure of the ear and where are the receptors for sound? Sound waves pass through the pinna (external ear) and ear canal, ultimately reaching the auditory apparatus of the middle and inner ear. The primary structures of the middle and inner ear that are involved in the detection of sound are: the typanic membrane, the ossicles, the oval window, the cochlea, and the organ of Corti. The organ of Corti contains the receptors for sound.

12. 12 The Structure of the Ear

13. 13 The Ossicles

14. 14 The Receptors for Sound

15. 15 Cochlea Slice

16. 16 Hair Cells Images Cilia of Outer Hair CellsCilia of Inner Hair Cells

17. 17 The Somatosensory System and the Auditory System 1. What are the major areas of the brain that are associated with the perception of touch? 2. What are the physical and perceptual dimensions of sound? 3. What is the structure of the ear and where are the receptors for sound?