Download Class 10: Other Senses

10/8/12
OTHER SENSES
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Biological Psychology
Dr. Steinmetz
FOR EACH SENSORY
SYSTEM
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¢ What
is the physical stimulus?
¢  What is the receptor/
transduction process?
¢  What is the neural pathway?
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LAW OF SPECIFIC NERVE ENERGIES
¢ Each afferent sensory nerve:
transmits information about a particular
stimulus
—  Receptors à central nervous system
— 
¢ Any
activity in that afferent sensory
nerve
— 
interpreted by the brain as specific to the
associated type of stimulus
For example:
—  the optic nerve carries visual information to the brain, if
artificially stimulated you “see”
—  the auditory nerve carries auditory information to the brain, if
artificially stimulated you “hear”
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
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PHYSICAL STIMULUS - AUDITION
¢  Sound
waves are periodic compressions of air
¢  2 important features of sound waves:
1. Wavelength Frequency = pitch
Hertz (Hz) = # of cycles / sec
The more cycles per second, the
higher the pitch or tone.
2. Amplitude = intensity - loudness
Vertical size measured in decibels
The larger the wave height, the
louder the sound.
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RECEPTORS & TRANSDUCTION - AUDITION
¢ Pinna
– collects sound used in
localization
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RECEPTORS & TRANSDUCTION - AUDITION
¢ Middle
ear –
tympanic
membrane
receives air wave
bones amplify
the wave
—  transmit to fluidfilled cochlea
(amplify = air to
fluid)
— 
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RECEPTORS & TRANSDUCTION - AUDITION
¢ Inner
ear =
cochlea has
hair cell
receptors
HEARING
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Auditory receptors = hair
cells
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AUDITORY TRANSDUCTION
PROCESS
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¢ Tectorial
membrane moves
with the vibrations
of fluid in the
cochlea
Movement opens
ion (K+) channels
in hair cells
(receptors) located
in the basilar
membrane
—  Endolymph (fluid in
cochlea) has high
concentration K+
— 
K+
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AUDITORY TRANSDUCTION
PROCESS
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¢ K+
comes into the hair
cells making them
more positive
activating voltagegated Ca2+ channels
¢ Hair cells release NT
•  NT (neurotransmitter)
from the hair cells
activates action
potentials in the
auditory nerve
K+
¢ http://www.youtube.com/watch?
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NR=1&feature=endscreen&v=0jyxhozq89g
¢ http://www.youtube.com/watch?
v=PeTriGTENoc&feature=related
¢ http://www.youtube.com/watch?
v=dyenMluFaUw
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Fig. 7-5, p. 194
CORTICAL AREAS - AUDITORY
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¢  Superior
Temporal Gyrus, A1 =
primary auditory cortex
tonotopic organization
•  Secondary auditory cortex =
complex tone processing,
Wernicke’s Area = speech
recognition
•  Association auditory cortex =
combine auditory signals with
meaning,
Angular Gyrus = speech
comprehension
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
PHYSICAL STIMULUS VESTIBULAR
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¢ Vestibular
system - responsible for balance,
posture, and eye movements
¢ 2 different stimuli and 2 sets of receptors:
— 
— 
head tilt / orientation relative to gravity
acceleration & deceleration (movement)
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
PHYSICAL STIMULUS - GUSTATION &
OLFACTION
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¢ Olfactory
(smell) stimuli are typically chemicals
suspended in the air
—  Tens of thousands of different olfactory stimuli
¢ Gustatory
(taste) stimuli are dissolved chemicals
(solution or saliva)
—  Sweet, Sour, Salty, Bitter, Umami, others?
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RECEPTORS - OLFACTORY
¢  Olfactory
receptors are
found in the back of
the nasal cavity.
¢  Olfactory receptors are
neurons.
¢  Olfactory receptor
neurons have cilia
suspended in a
mucous fluid.
¢  Olfactory 7-TM
receptors similar to
NT metabotropic
receptors.
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NEURAL PATHWAY - OLFACTORY
¢  Olfactory
receptors located in
the olfactory mucosa →
Olfactory bulb → Olfactory
nerve → Amygdala &
Thalamus →
¢  Thalamus to Primary
Olfactory cortex in the
frontal lobe (piriform) &
limbic system
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WHY DO SMELLS MAKE US
REMEMBER?
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VOMERONASAL ORGAN
¢ Small
specialized
component of the
olfactory system
¢ Separate system:
different receptors
& neural pathway
¢ More prominent in
non-human
mammals
¢ Receives
pheromones
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PHEROMONE CHEMICAL STIMULI
¢ Pheromones
are chemicals
given off by an animal
which have an effect on
the behavior of other
animals (reproductive or
sexual behavior)
¢  Vomeronasal organ
(VMO)
¢ Are there human
pheromones?
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
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RECEPTOR - GUSTATORY
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¢ Taste
Buds
contain taste
receptor cells
(TRCs)
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TRANSDUCTION - GUSTATORY
Salt = ionotropic
Tastant Entry
Sour = ionotropic
Ion (K+) Block
Taste Cell
Tight Junction
Bitter =
Metabotropic
Sweet =
Metabotropic
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¢ Taste
Receptors
¢  Gustatory
Nucleus
(medulla)
¢  VPM nucleus
of thalamus
¢ Gustatory
cortex
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CORTICAL AREAS - GUSTATORY
¢  Insula
& Frontal
Operculum =
primary taste
perception
¢  Orbitofrontal
Cortex = flavor
¢  Hypothalamus =
hunger and satiety
¢  PBN/Amygdala =
emotion (cravings or
aversions)
PBN / Amygdala
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OUTLINE
¢ Auditory
System
¢ Vestibular System
¢ Olfactory System
¢ Gustatory System
¢ Somatosensory System
PHYSICAL STIMULUS - SOMATOSENSATION
¢ There
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are many different stimuli:
—  Touch
– pressure & vibration
(movement),
—  Nociceptors - temperature &
tissue damage (pain)
¢ Each
stimulus has at least one
specialized receptor (several
have at least 2 receptors)
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RECEPTORS - SOMATOSENSORY
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SKIN RECEPTORS
¢ Pacinian
corpuscles –
touch, high frequency
vibration
¢ Meissner's corpuscles –
pressure, low frequency
vibration
¢ Merkel's disks - pressure
¢ Ruffini's corpuscles –
stretch, vibration (not
pressure)
¢ Free-nerve endings temperature, pain
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TRANSDUCTION & NEURAL
CODING
¢  Touch
bends the
receptor opening ion
channels
¢  Pacinian Corpuscle:
pressure onset / offset
detector
•  The structure of the
Pacinian corpuscle
makes the receptor
selective to onset &
offset stimuli and not
to constant stimulus
TOUCH PATHWAY &
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Action
potential
output
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CORTICAL AREAS
¢  Sensory
neurons
enter the spinal cord
organized by
dermatome, form
synapses, & then
send axons up the
dorsal spinal cord
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TOUCH PATHWAY &
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CORTICAL AREAS
¢  Cross
midline at
brainstem, synapse at
VP thalamus,
terminate at
contralateral S1,
somatosensory cortex
(postcentral
gyrus)
INCOMING PAIN SIGNALS
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¢ Difference
between incoming
temperature signals and pain signals
is the release of substance P as the
neurotransmitter for PAIN
¢ Specialized signal for
pain that is unique
¢ Pain is a very
Pain input
important signal
to brain
to recognize &
respond to!
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PAIN MANAGEMENT PATHWAYS
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¢ Periaquaductal
Grey
& Raphe nuclei send
endorphins to reduce
incoming pain at
spinal cord level
¢ Localized release
versus opiate
medicines which
have global effects
GATE CONTROL THEORY
¢ Signal
from the
PAG / Raphe N.
closes the gate.
¢ Localized release
of endorphins at
the precise site
¢ Inhibits incoming
pain sensations
through
heteroreceptors!
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Brain output
to block pain
PAG &
Raphe N.
Inhibits
substance P
release
Pain input
to brain
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TWINS ATTACHED AT THE
THALAMUS?
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¢ http://www.nytimes.com/
2011/05/29/magazine/couldconjoined-twins-share-amind.html
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FOR NEXT TIME…
¢  Read
Ch. 9: Regulation
¢  EMG Statistical Analysis Olin
212 on Wednesday
¢  Peer Review of Lab Reports
due Thursday
¢ Study for Exam 2
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