PSYCH 15 Lecture Notes - Lecture 7: Solitary Tract, Taste, Olfactory Mucosa
Chapter 7: Mechanisms of Perception: Hearing Touch, Smell, Taste, and Attention
- Auditory system
o Natural sounds are complex patterns of vibrations
o Perception created by the brain from bottom up and top down about air (nothing noisy about
air)
o Amplitude: height of the wave, the higher it is the louder
o Frequency: how long wavelengths are, higher frequency higher pitch
o Complexity: timbre – quality of the sound; sound a trumpet makes vs a flute if they play the
same note
▪ Timbre created by many many pure waves
- Fourier analysis: breaks down natural sounds into sine waves
- The Ear
o Tympanic membrane will vibrate and is connected to bones called the (occicles)
▪ Hammer→anvil→sitrrup aka mallus→incus→stapes
▪ Will go to the cochlear – spiral shaped like a snail
o End of the stirrup will push against the oval window which will vibrate
▪ The water against it will flow in the direction of the arrow and will go back and forth bc
of the pressure
o Air pressure of waves has been converted to vibrations
- The organ of corti
o Tectorial membranes
o Hair cells – instead of dendrites, stereociia
▪ Fire action potentials
▪ Transduce mechanical energy into neural impulses
o Vibrations cause the tectorial membrane and basilar membrane vibrations
o We detect pitch on the base of the corti
▪ If iratios happe at the ape ill e lo …
▪ When hair cells die, you cant get them back
• Hair cells near the base tend to die earlier, as part of natural life aka we lose our
ability to detect high pitches as we age
• Correlation between age and how you can perceive pitches
• Presbyacusis/Presbycusis
- From the Ear to the Primary Auditory Cortex
o Auditory nerves
o Cochlear nuclei
o Just know the individual systems; cochlear→cochlear nuclei
o Mgn thalamus
▪ Every system makes a stop in the thalamus
o A1
o Superior olives play a role in letting us locate sounds
▪ Both lateral and medial on both sides
▪ More to the side – lateral olive – amplitude differences
• The further way the sound it, the softer its get when it gets to you
▪ More to the middle – medial superior olive – arrival time differences
• Hear a sound if it hits one ear before the other
o Pinnae
- Auditory cortex
o Located in temporal lobe
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chapter 7: mechanisms of perception: hearing touch, smell, taste, and attention. Fourier analysis: breaks down natural sounds into sine waves. Auditory cortex: located in temporal lobe, a1 a2 a3, belt is a2, everything else is parabelt, 10 separate areas (goes up to a10) What sounds should be used to study auditory cortex: should only use pure tones. Two major somatosensory pathways: dorsal-column medial-lemniscus system, left hemisphere processes right side and vice versa cross over. Cortical areas of somatosensation: post central gyrus in parietal lobe, each step you go gets more and more complex. Astereognosia- inability to recognize object by touch: damage to cortical ilias, cant process sensation, damage in parietal lobe. Asomatognosia: failure to re(cid:272)og(cid:374)ize o(cid:374)e"s o(cid:449)(cid:374) body parts, paired usually with anosognosia (lack of disease knowledge) (cid:449)o(cid:374)"t a(cid:272)k(cid:374)o(cid:449)ledge that the(cid:455)"re diseased. Neuropathic pain: severe chronic pain in the absence of a recognizable pain stimulus you feel pain for no reason, know very little about this.
