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Chapter Seven. Nonvisual Sensation and Perception. CHAPTER 7 NONVISUAL SENSATION AND PERCEPTION. Audition. Sound as a Physical Stimulus Intensity Amplitude of sound wave Sound waves vary from quiet whisper to rock band Logarithmic scale of sound intensity Frequency
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Chapter Seven Nonvisual Sensation and Perception
Audition • Sound as a Physical Stimulus • Intensity • Amplitude of sound wave • Sound waves vary from quiet whisper to rock band • Logarithmic scale of sound intensity • Frequency • Number of cycles per unit of time, wavelength of a sound stimulus • Pitch determined by the wave having the lowest frequency (fundamental frequency) • Timbre, or quality, determined by additional waves • Ultrasound: Frequencies above 20,000 Hz • Infrasound: Frequencies less than 20 Hz
Table 7.1 Sounds Vary Along the Dimensions of Amplitude, Frequency, and Complexity
Audition • The Structure and Function of the Auditory System • The Outer Ear – pinna and auditory canal • The Middle Ear – eardrum, ossicles (malleus, incus, stapes), tympanic membrane, oval window • The Inner Ear – semicircular canal, cochlea
Figure 7.6 Sound Frequencies Are Translated by the Basilar Membrane
Figure 7.7 The Movement of the Cilia Regulates Neurotransmitter Release by Hair Cells
Audition • The Structure and Function of the Auditory System • Central Auditory Pathways • Dorsal and ventral cochlear nucleus of the medulla • Superior olive • Inferior colliculus • Medial geniculate nucleus (MGN) of the thalamus • The Auditory Cortex • Primary auditory cortex – columns respond to single frequencies • Secondary auditory cortex – activated by complex stimuli
Figure 7.9 Tonotopic Organization is Maintained by the Auditory Cortex
Audition • Auditory Perception • Pitch Perception • Due to frequency, intensity and context of stimulus • Tonotopic organization • Loudness Perception • Decibel level describes physical qualities of sound stimulus • Loudness is human perception of that stimulus • Equal loudness contours • Localization of Sound • Comparison of arrival times of sounds at each ear and differences in intensities important for horizontal plane • Pinna important for localizing sound in vertical plane
Figure 7.11 We Localize Sound by Comparing Arrival Times at Both Ears
Hearing Disorders • Age-related hearing loss • Poor circulation to the inner ear • Effects of exposure to loud noise • Conduction loss • Loss due to damage to inner ear, auditory pathways, or auditory cortex
The Body Senses • Vestibular System • Movement Receptors of the inner ear • Semicircular canals • Otolith organs: Utricle and Saccule • Central Pathways • Axons originating in otolith organs and semicircular canals • Ventral posterior (VP) nucleus of the thalamus • Primary somatosensory cortex and primary motor cortex
The Body Senses • Touch • Hairy skin and glabrous skin (hairless) • Layers • Epidermis • Dermis • Subcutaneous tissue • Touch Receptors – mechanoreceptors • Touch Pathways
Figure 7.16 The Four Classes of Sensory Axons Differ in Size and Speed
Figure 7.17 Dermatomes Are Areas of Skin Served by the Dorsal Roots of One Spinal Segment
Figure 7.19 Somatosensory Information Is Sent to the Ventral Posterior and Intralaminar Nuclei of the Thalamus
The Body Senses • Touch • Somatosensory Cortex • Primary somatosensory cortex found in postcentral gyrus of parietal lobe • Secondary somatosensory cortex found in posterior parietal lobe • Plasticity of Touch • Somatosensory cortex rearranges itself in response to changes in the amount of input it receives • Somatosensory Disorders
The Body Senses • Temperature • Thermoreceptors • Cold fibers • Warm fibers • Share pathways with sense of pain
The Body Senses • Pain • A Purpose for Pain • Receptors for Pain • Nociceptors • Chemicals that activate nociceptors • Pain Pathways to the Brain • Ascending pain fibers (A and C) • Substance P • Substantia gelatinosa, spinothalamic pathway, ventral posterior (VP) nucleus of the thalamus, anterior cingulate cortex, somatosensory cortex • Managing Pain
Figure 7.26 Olfactory Information Travels from the Epithelium to the Brain
The Chemical Senses • Taste • Taste Receptors • Found on tongue and other areas of the mouth • Papilla contain taste buds • Taste buds have 50-150 receptor cells • Taste Pathways • Taste fibers in tongue form parts of cranial nerves VII, IX, and X • Gustatory nucleus of the medulla • Ventral posterior medial (VPM) nucleus of the thalamus • Gustatory cortex in the parietal lobe • Orbitofrontal cortex in the frontal lobe