Transcript Biological Psychology CH 5

Chapter 5: The ‘Other’ Sensory
Systems
Audition: Hearing
1.
What is the stimulus in the auditory system?
2.
Important characteristics of the auditory
stimulus:


Frequency = pitch
Amplitude (decibels) = volume/ loudness of a
sound
1.
Anatomy of the Ear
Outer Ear
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2.
Middle Ear
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3.
Pinna
Auditory canal
The tympanic membrane
Bones: malleus, incus, & stapes
Inner Ear

Cochlea
Structures of the Ear
More about the Cochlea
1.
The cochlea is fluid filled and is lined with the
sensory cells for hearing
2.
Down the center of the cochlea runs the Basilar
membrane
3.
The cells that actually ‘hear’ are called hair cells
4.
The hair cells transfer their information to the
cells of the auditory nerve
The Cochlea in Detail
Pitch perception in the Ear
1.
Frequency Theory – says that the basilar membrane
moves in synchrony with the frequency of a sound
wave

2.
What do you know about Action Potentials that would
make this theory impossible??
Place Theory – says that parts of the basilar
membrane move like keys on an instrument, just
the part of the membrane responsible for a given
pitch moves
In Reality…

It turns out that we use a combination of
place and frequency:

For tones less than 100 Hz, our APs can keep up
with frequency theory

Hair cells at the base of the cochlea, near the
oval window respond best to high frequency
tones, while hair cells at the apex (middle) of the
cochlea respond best to lower tones
Pitch Perception in the Brain
1.
Auditory info undergoes cross-over – what
does this mean?
2.
The auditory cortex is located in the
temporal lobes



Sound location
The cortex is tonotropic
Brain injury to this part of the brain does not result in
total deafness
Problems with Hearing
1.
Conductive Deafness
2.
Nerve Deafness
3.
Tinnitus
Taste
Taste is made up of 4 basic sensations:
1.
3.
Sweet
Salty
Bitter
4.
Sour
1.
2.
2.
3.
Those bumps AREN’T buds!
Inside each bud are about 50-100 taste receptors.
these receptors replace themselves every couple of
weeks
The Tongue
Location of Taste on the tongue
1.
Most taste buds are on the edges of the
tongue
2.
Different parts of the tongue are better at
tasting different taste sensations
3.
The taste receptors can send different
messages to the brain based on prior
exposure to certain chemicals
Taste Info in the Brain
1.
Cranial nerves carry taste info from the
tongue to the brain
2.
Thalamus  Medulla  Limbic system 
Insular cortex (frontal lobe) = primary taste
cortex
3.
The brain receives ipsalateral information
from the tongue – what does that mean?
Olfaction: Smell
1.
Olfaction, like taste, is a chemical sense
2.
The olfactory membrane holds the receptor cells,
the ends of which terminate the olfactory bulb
3.
We don’t really know how receptor cells work
4.
Smell is very closely related to memory – why
might this be? Think location…
Vomeronasal Receptors
1.
This is the organ through which animals
sense pheromones
2.
Pheromones are chemicals that have a
distinct effect on other members of our
species
3.
Can humans sense pheromones? How do we
know?

Totally gross research, that’s how.
Vestibular Sense

This is our sense of head position and
balance

There are two important structures in the
inner ear, next to the cochlea that make up
the vestibular organ:


The semicircular canals
The otolith organs
Proprioception
1.
2.
3.
This is our sense of our body’s position in the world
Proprioception happens because of special
receptors in our joints
•
You may have fooled the receptors before, if not
try it with a friend
This information is combined with our vestibular
sense to help us decide how to move our bodies in a
given situation
Somatosensation
1.
2.
This is our sense of touch, body movement, and
position of our limbs.
Touch includes:

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3.
Temperature
Pain
Pressure
Itch
Tickle
There are at least 7 kinds of touch receptors in your
skin – I want you to know 2:
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Pacinian Corpuscles
Meissner’s Corpuscles
How does Touch Info get to the Brain?
1.
2.
From the head up, touch info enters via the cranial
nerves, from below the head via the spinal cord
 The cord has distinct pathways for different
kinds of touch information
Once in the brain, the info stops at the…, then heads
to the somatosenory cortex in the…. (you guys
know this!!)
Pain
1.
There are different kinds of
neurotransmitters for different kinds of pain


2.
Glutamate
Substance P
Endogenous opiates (endorphins)
Gate-Control Theory of Pain
1.
This theory says that the spinal cord actually
makes ‘decisions’ about what pain
information gets up to the brain
2.
Endorphin release in the midbrain causes the
brainstem to inhibit release of substance P
The blurred line between Somatosensory
Sense and Chemical Sense
1.
Our ability to detect painful heat can be
evoked by application of a chemical called
capsaicin
2.
How can exposure to capsaicin actually
make you feel less pain?
The Psychology of Pain
1.
Circumstantial influence
1.
Pain thresholds
2.
Pain is ADAPTIVE
Pain Control

While we still don’t totally understand the
mechanisms of pain sensation and
perception, pain control is a huge area of
research

Techniques range from physical intervention
to psychological techniques
What the heck is an itch, anyhow?
1.
An itch is a sensation on the skin created by
histamine release
2.
Pain and itch inhibit each other
3.
Itch sensations are also adaptive
Sensory Interaction

This is the idea that the sensory organs can
influence each other.


Can anyone give me an example?
The best example I can think of is the
influence of…
Attention?
1.
Why are we talking about attention in the
sensory chapter and not in the consciousness
chapter?
2.
Does our brain activity change when we are
attending to a given stimulus?
Selective Attention
1.
2.
Selective attention is our ability to focus on
one thing and ignore pretty much everything
else.
•
Selective attention is what we ‘choose’ to
attend to.
This is a very important, adaptive skill
Neglect
1.
Neglect is the opposite of attention
2.
Brain damage often causes a non-voluntary,
specific neglect

Spatial neglect
Attention Deficit Disorder
1.
People with ADD or ADHD exhibit high
levels of distractibility, hyperactivity,
impulsivity, poor control of anger, etc.
2.
Is this a true mental disorder or a social
phenomenon?
Testing for ADD/ADHD
1.
Choice-delay task
2.
Stop Signal task
3.
Attentional blink task
Brain Differences?
1.
ADHD does run in families
2.
May be a dopamine receptor problem
3.
Smaller overall brains, with specific size
differences in the right prefrontal cortex &
cerebellum
4.
Too much slow-wave activity
Treatments
1.
Stimulant drugs are often prescribed
2.
Brainwave biofeedback might help
3.
There are behavioral techniques that can help: