Transcript chapter 7 nonvisual sensation and perception

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
• 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
Figure 7.2 The Auditory World Differs Across
Species
Table 7.1 Sounds Vary Along the Dimensions of
Amplitude, Frequency, and Complexity
Table 7.2 Intensity Levels of Common Sounds
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 7.4 The Anatomy of the Ear
Figure 7.5 The 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 7.8 Auditory Pathways from the Cochlea
to the Cortex
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 7.10 Equal Loudness Contours
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
Figure 7.13 The Vestibular Structures of the
Inner Ear
The Body Senses
• Touch
– Hairy skin and glabrous skin (hairless)
– Layers
• Epidermis
• Dermis
• Subcutaneous tissue
– Touch Receptors – mechanoreceptors
– Touch Pathways
Figure 7.14 Mechanoreceptors of the Skin
Table 7.3 Major Features of the
Mechanoreceptors
Figure 7.15 Two-Point Discrimination Thresholds
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
Figure 7.20 Somatosensory Cortex
Figure 7.21 Drawings of a Patient with Neglect
Syndrome
The Body Senses
• Temperature
– Thermoreceptors
• Cold fibers
• Warm fibers
– Share pathways with sense of pain
Figure 7.22 Responses by Cold and Warm Fibers
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 7.23 Ascending Pain Pathways
Figure 7.24 Descending Messages Influence 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
Figure 7.27 The Taste Receptors
Figure 7.28 Taste Pathways to the Brain