Download PSYC550 Sense or Senseless

PSYC550 Biological Bases of
Behavior
Sense or Senseless?
The Stimulus
• sensory receptors
– A specialized neuron that detects a particular category
of physical events.
• sensory transduction
– The process by which sensory stimuli are transduced
into slow, graded receptor potentials.
• receptor potential
– A slow, graded electrical potential produced by a
receptor cell in response to a physical stimulus.
The Stimulus
• hue
– One of the perceptual dimensions of color; the
dominant wavelength.
• brightness
– One of the perceptual dimensions of color; intensity.
• saturation
– One of the perceptual dimension of color; purity.
Anatomy of the Visual
System
• vergence movement
– The cooperative movement of the eyes, which ensures
that the image of an object falls on identical portions of
both retinas.
• saccadic movement
– The rapid, jerky movements of the eyes used in
scanning a visual scene.
• pursuit movement
– The movement that the eyes make to maintain an image
of a moving object on the fovea.
Anatomy of the Visual
System
• accommodation
– Changes in the thickness of the lens of the eye, accomplished by the ciliary
muscles, that focus images of near or far objects on the retina.
• retina
– The neural tissue and photoreceptive cells located on the inner surface of the
posterior portion of the eye.
• rod
– One of the receptor cells of the retina; sensitive to light of low intensity.
• cone
– One of the receptor cells of the retina; maximally sensitive to one of three
different wavelengths of light and hence encodes color vision.
Anatomy of the Visual
System
• photoreceptor
– One of the receptor cells of the retina; transduces photic energy
into electrical potentials.
• fovea
– The region of the retina that mediates the most acute vision of
birds and higher mammals. Color-sensitive cones constitute the
only type of photoreceptor found in the fovea.
• optic disk
– The location of the exit point from the retina of the fibers of the
ganglion cells that form the optic nerve; responsible for the blind
spot.
Copyright © Allyn & Bacon 2007
Anatomy of the Visual
System
• bipolar cell
– A bipolar neuron located in the middle layer of the retina, conveying
information from the photoreceptors to the ganglion cells.
• ganglion cell
– A neuron located in the retina that receives visual information from
bipolar cells; its axon give rise to the optic nerve.
• horizontal cell
– A neuron in the retina that interconnects adjacent photoreceptors and
the outer processes of the bipolar cells.
• amacrine cell
– A neuron in the retina that interconnects adjacent ganglion cells and
the inner processes of the bipolar cells.
Copyright © Allyn & Bacon 2007
Anatomy of the Visual
System
• dorsal lateral geniculate nucleus
– A group of cell bodies within the lateral geniculate body
of the thalamus; receives inputs from the retina and
projects to the primary visual cortex.
• magnocellular layer
– One of the inner two layers of neurons in the dorsal
lateral geniculate nucleus; transmits information
necessary for the perception of form, movement,
depth, and small differences in brightness to the
primary visual cortex.
Anatomy of the Visual
System
• parvocellular layer
– One of the four outer layers of neurons in the dorsal
lateral geniculate nucleus; transmits information
necessary for perception of color and fine details to the
primary visual cortex.
Copyright © Allyn & Bacon 2007
Anatomy of the Visual
System
• calcarine fissure
– A horizontal fissure on the inner surface of the
posterior cerebral cortex; the location of the primary
visual cortex.
• striate cortex
– The primary visual cortex.
• optic chiasm
– A cross-shaped connection between the optic nerves,
located below the base of the brain, just anterior to the
pituitary gland.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Coding of Visual
Information in the Retina
• receptive field
– The portion of the visual field in which the presentation
of visual stimuli will produce an alteration in the firing
rate of a particular neuron.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Coding of Visual
Information in the Retina
• negative afterimage
– The image seen after a portion of the retina is exposed
to an intense visual stimulus; consists of colors
complementary to those of the physical stimulus.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Analysis of Visual Information:
Role of the Striate Cortex
• simple cell
– An orientation-sensitive neuron in the striate cortex whose
receptive field is organized in an opponent fashion.
• complex cell
– A neuron in the visual cortex that responds to the presence of a
line segment with a particular orientation located within its
receptive field, especially when the line moves perpendicular to
its orientation.
• hypercomplex cell
– A neuron in the visual cortex that responds to the presence of a
line segment with a particular orientation that ends at a particular
point within the cell’s receptive field.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Analysis of Visual
Information: Role of the
Striate Cortex
• cytochrome oxidase (CO) blob
– The central region of a module of primary visual
cortex, revealed by a stain for cytochrome oxidase;
contains wavelength-sensitive neurons; part of the
parvocellular system.
• ocular dominance
– The extent to which a particular neuron receives more
input from one eye than from the other.
Copyright © Allyn & Bacon 2007
Analysis of Visual Information:
Role of the Visual Association
Cortex
• extrastriate cortex
– A region of visual association cortex; receives fibers
from the striate cortex and from the superior colliculi
and projects to the inferior temporal cortex.
• dorsal stream
– A system of interconnected regions of visual cortex
involved in the perception of spatial location, beginning
with the striate cortex and ending with the posterior
parietal cortex.
Analysis of Visual
Information: Role of the
Visual Association Cortex
• ventral stream
– A system of interconnected regions of visual cortex
involved in the perception of form, beginning with the
striate cortex and ending with the inferior temporal
cortex.
• inferior temporal cortex
– In primates the highest level of the ventral stream of
the visual association cortex; located on the inferior
portion of the temporal lobe.
From the retina to other
parts of the brain
• Superior colliculus
– Head orientation to movements in peripheral field
• Accessory optic nucleus
– Eye movements to compensate for head movements
• Suprachiasmatic nucleus
– Controls circadian rhythms
• Pineal body
– Controls circannual rhythms
Copyright © Allyn & Bacon 2007
Analysis of Visual Information:
Role of the Visual Association
Cortex
• visual agnosia
– Deficits in visual perception in the absence of blindness; caused
by brain damage.
• apperceptive visual agnosia
– Failure to perceive objects, even though visual acuity is relatively
normal.
• associative visual agnosia
– Inability to identify objects that are perceived visually, even
though the form of the perceived object can be drawn or
matched with similar objects.
• prosopagnosia
– Failure to recognize particular people by the sight of their faces.
Damage to the parietal lobe
• Critical for spacial perception and locating objects
in space
• ocular apraxia
– Difficulty in visual scanning.
• simultanagnosia
– Difficulty in perceiving more than one object at a time.
• Optic ataxia
– Deficit in reaching for objects under visual guidance
Hearing…
Copyright © Allyn & Bacon 2007
Audition
• tympanic membrane
– The eardrum.
• ossicle
– One of the three bones of the middle ear (malleus, incus, stapes).
• malleus
– The “hammer”; the first of the three ossicles.
• incus
– The “anvil”; the second of the three ossicles.
• stapes
– The “stirrup”; the last of the three ossicles.
Audition
• cochlea
– The snail-shaped structure of the inner ear that contains the
auditory transducing mechanisms.
• oval window
– An opening in the bone surrounding the cochlea that reveals a
membrane, against which the baseplate of the stapes presses,
transmitting sound vibrations into the fluid within the cochlea.
• organ of Corti
– The sensory organ on the basilar membrane that contains the
auditory hair cells.
• hair cell
– The receptive cell of the auditory apparatus.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Audition
• basilar membrane
– A membrane in the cochlea of the inner ear; contains
the organ of Corti.
• tectorial membrane
– A membrane located above the basilar membrane;
serves as a shelf against which the cilia of the auditory
hair cells move.
Audition
• cilium
– A hair-like appendage of a cell involved in movement or
in transducing sensory information; found on the
receptors in the auditory and vestibular system.
• tip link
– An elastic filament that attaches the tip of one cilium to
the side of the adjacent cilium.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
From the ear to…
• Medulla
– Cochlear nuclei
– Superior olivary nuclei
– Lateral lemniscus
• To inferior colliculus
• To medial geniculate
• To auditory cortex
Audition
• cochlear nerve
– The branch of the auditory nerve that transmits
auditory information from the cochlea to the brain.
• superior olivary complex
– One of a group of nuclei in the medulla; involved with
auditory functions, including localization of the source
of sounds.
Audition
• lateral lemniscus
– A band of fibers running rostrally through the medulla
and pons; carries fibers of the auditory system.
• tonotopic representation
– A topographically organized mapping of different
frequencies of sound that are represented in a particular
region of the brain.
Copyright © Allyn & Bacon 2007
Audition
• place code
– The system by which information about the different
frequencies is coded by different locations on the basilar
membrane.
• cochlear implant
– An electronic device surgically implanted in the inner
ear that can enable a deaf person to hear.
Copyright © Allyn & Bacon 2007
What happens if we give a
bilateral lesion of the
auditory cortex?
1. Can detect pitch and
intensity, but not
“melodies”
2. Can hear, but can’t
detect pitch or
intensity
3. Will be completely
deaf
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What happens if we lesion
the inferior colliculus?
1. Can detect pitch and
intensity, but not
“melodies”
2. Can hear, but can’t
detect pitch or
intensity
3. Will be completely
deaf
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What happens if we lesion
the lateral lemniscus?
1. Can detect pitch and
intensity, but not
“melodies”
2. Can hear, but can’t
detect pitch or
intensity
3. Will be completely
deaf
af
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m
pl
et
co
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ill
b
W
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10
Somatosenses
• cutaneous sense
– One of the somatosenses; includes sensitivity to stimuli
that involve the skin.
• kinesthesia
– Perception of the body’s own movement.
• organic sense
– A sense modality that arises from receptors located
within the inner organs of the body.
Somatosenses
• glabrous skin
– Skin that does not contain hair; found on the palms and
soles of the feet.
• Ruffini corpuscle
– A vibration-sensitive organ located in hairy skin.
• Pacinian corpuscle
– A specialized, encapsulated somatosensory nerve ending
that detects mechanical stimuli, especially vibrations.
Somatosenses
• Meissner’s corpuscle
– The touch-sensitive end organs located in the papillae,
small elevations of the dermis that project up into the
epidermis.
• Merkel’s disk
– The touch-sensitive end organs found at the base of the
epidermis, adjacent to sweat ducts.
Copyright © Allyn & Bacon 2007
Somatosenses
• phantom limb
– Sensations that appear to originate in a limb that has
been amputated.
• nucleus raphe magnus
– A nucleus of the raphe that contains serotonin-secreting
neurons that project to the dorsal gray matter of the
spinal cord and is involved in analgesia produced by
opiates.
Copyright © Allyn & Bacon 2007
Copyright © Allyn & Bacon 2007
When resonance causes the
cilia to move:
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It
1. It tickles
2. It causes the
tympanic membrane
to vibrate
3. Semicircular canals
vibrate
4. Calcium channels
open
10
The neural structure noted for
control of circadian rhythms is the:
1. Accessory optic
nucleus
2. Suprachiasmatic
nucleus
3. Pineal gland
4. Superior colliculus
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