Study sets, textbooks, questions
Upgrade to remove ads
Physiological Psych Chapter 6
Terms in this set (90)
any energy capable of exciting a receptor
what is a stimulus?
convert sensory information into electrical impulses that can be interpreted and understood by the brain
what is the job of stimulus receptors?
associated with touch, pressure, vestibular, audition
associated with light
-a stimulus sufficient to initiate a response in the nervous system must be present
-a receptor must convert the stimulus to a nerve impulse
-the conduction of the nerve impulse must be transmitted from the receptor the brain
-Interpretation of the impulse must occur in a specific portion of the brain
what must be present in order to perceive a sensation?
-ABSORB PHYSICAL ENERGY from the environment
-CONVERT (TRANSDUCE) THE ENERGY into a neural impulse
-THE LEVEL OF RESPONSE IS DETERMINED BY THE INTENSITY OF STIMULATION-- RATE'S LAW! i.e. perceiving a bright color vs. a dull color
All receptors do what?
tonic and phasic receptors
what are the two types of receptors?
continue to fire at a relatively constant rate as long as the stimulus is maintained...slow to adapt.
ex. the receptors remain active as long as stimulus is present, ex. sitting in a chair you are "aware" that you are sitting meaning you can feel the chair until you get up from the chair.
what do tonic receptors do?
respond with a burst of APs when stimulus is first applied, but quickly reduce their rate of firing, when the stimulus is maintained...THEY ALERT US TO CHANGE IN OUR ENVIRONMENT
-allows brain to process other stimulus
what do phasic receptors do?
specialized nerve cells that transduce energy into neural signals; they lack axons, but form synapses with dendrites of other sensory neurons
what are sensory receptors?
sensory messages are carried via separate pathways to different areas of the brain, but all use the same neural impulse
what is the Law of Specific Nerve Energies?
receptors are _______ specific.
true or false: receptors detect a small range of energy levels
what wavelength range can the eyes detect?
what frequency range can the ears detect?
what do tastebuds detect?
to detect electromagnetic radiation emitted by objects
what is the function of the visual system?
wavelength of light (nM)
what is the hue of perceived color related to?
intensity (amplitude) of the radiation
what is the brightness of the perceived color related to?
-discriminate figure from background (food or rock?)
-detect movement (predator or prey?)
-detect color (is fruit ripe?)
what are the functions of vision?
what is the part of the eye that apertures or dilates to admit light?
what is the transparent structure behind the pupil that changes shape to help focus images on the retina? It focuses light.
what are the photoreceptive elements that transduce light stimulus?
-Pupil (opening in iris)
-Lens (rounded for nearby objects; flattened for distant objects
-retina (image is upside-down and reversed)
what its the path of light through the eye?
vergence, pursuit, saccadic
what are three types of eye movements?
the eyes rotate to keep an object on corresponding parts of the retina (ex. eyes "converge"; eyes rotate in as object gets closer)
what is vergence movement?
following an object to keep it on the same part of the retina (the fovea, to maximize detail and color appreciation) ex. eyes rotating left to right to follow a moving object
what is pursuit movement?
eyes fixate on objects during "smooth pursuit"
-eyes also "jump back and forth"- they are not stationary!
-eyes are always moving to keep things new and fresh; constantly refreshing environment to ensure that continue to see things clearly
what is saccadic movement?
-Ganglion Cell Layer
What are the three layers of the retina?
the layer at the back of the eye, and the first area to respond to light, this receptor transducers light into electrochemical imputes (and eventually action potentials) and sends this information to the bipolar layer. Part of the PNS.
what is the photoreceptor layer?
the second layer to respond to light; its arms connect to the shallowest and deepest parts of the retina allowing it to receive information from the photoreceptors and send it to the ganglion cell. Part of the PNS
what is the bipolar layer?
the third layer to respond to light; neurons whose axons travel through the optic nerves and carry visual information to the rest of the brain. Part of the CNS
what is the ganglion layer?
The photoreceptor layer is the farthest from light, and the ganglion layer is actually closest to light, however, light is interpreted in the photoreceptor layer first, then moves to the bipolar layer, than to the ganglion layer, but in order to reach the photoreceptor layer, light must actually pass through the other two layers first.
What is the order light travels in the retina?
rods and cones
what are two types of photoreceptors located within the retina?
structures located in the membrane of the outer segment of rods and cones which are a special chemical involved in visual perception?
-light sensitive (not color)
-found in PERIPHERY OF RETINA
-low activation threshold
what are rods?
-are color sensitive
-found mostly in FOVEA
what are cones?
the center of the retina
what is the fovea?
true or false: the outer segments of a rod or cone contain different photopigments that react to light
people can't identify color as well in their peripheral vision because there aren't as many cones, but, in dark spaces, can identify objects better in their peripheral vision than in the fovea
the distribution of rods and cones in the retina means that...
opsin (a protein) and retinal (a lipid)
the two molecules that make up photopigments are what?
In the dark, sodium and calcium channels are kept _______
cGMP, allows the release of NT (glutamate) which hyper polarizes the bipolar cell membrane, and inhibits its functioning. (ON)
what keeps sodium and calcium ion channels open, and why?
it splits them apart into opsin and retinal.
What does light do to photopigments?
in the dark, cGMP opens sodium and calcium ion channels, releasing glutamate to bipolar cells, which hyperpolarizes them into ON, inhibiting their function, in the light, the photopigment is split into opsin and retinal which activates G protein (transducer), which activates phosphodiesterase which destroys cGMP, which closes the ion channels which reduces NT release, allowing bipolar cells to be switched to OFF allowing them to function.
explain the transduction of light
depolarization ____________ the release of glutamate, and hyper polarization ____________ the release of glutamate.
ON bipolar cells are ______________ by glutamate
OFF bipolar cells are _____________ by reduced glutamate release
to hyper polarize the photoreceptors and reduce the release of NT
what is the net effect of light?
hyperpolarizing membrane potential
what is the photoreceptors response to light?
depolarizing membrane potential (disinhibitory)
what is the bipolar cells response to light?
recording action potentials (excitatory)
what is the ganglion response to light?
light acts to INHIBIT ON bipolar cells by releasing phosphodiesterase destroying cGMP, reducing glutamate release, which is DEINHIBITORY for bipolar cells, turning them OFF stimulating their normal function.
what does light do for ON and OFF bipolar cells?
signals from ganglion cells are sent to the thalamus via the optic nerve
where are signals from the ganglion cells sent?
6, 2 inner, 4 outer
the lateral geniculate nucleus has how many layers?
contain larger cells (magnocellular (large soma)) transducing info like form, movement, depth, and brightness.
the inner 2 layers of the lateral geniculate nucleus does what?
contains small cells (pervocellular, small soma) controlling SMALL or FINE details like color, and fine detail discrimination.
what do the outer 4 layers of the lateral geniculate nucleus do?
lesion 1: analogous to losing an eye, you can't see out of one eye
lesion 2: BITEMPORAL HEMIANOPSIA cuts input from nasal retinas, so you lose peripheral vision NOTE: optic chaism, think pituitary tumor.
lesion 3: loss of left hemifield, both eyes will be blind to anything the left side of the world. NOTE: reason is because all information from the LVF is interpreted by right brain, so a lesion in this location in the RIGHT BRAIN causes a loss of info presented to the LVF. If this lesion were on the other side in the LEFT BRAIN, it would cause a loss of vision to all info presented to the RVF because vision CONTRALATERAL
lesion 4: LEFT SUPERIOR QUADRANT-ANOPSIA can't see up high on one side in both eyes
lesion 5: LEFT-INFERIOR QUDRANT-ANOPSIA; lose lower vision on one side in both eyes
lesion 6: MACULAR SPARRING can't see left hemifield except in fovea the loss is not a complete hemifield.
what would lesions at each of these positions cause?
loss of vision at lesion two can be caused by a pituitary tumor pushing on the optic chasm, causing the loss of that contralateral vision.
what could cause a loss of vision at lesion 2?
you can't see color in LVF
what happens if we lesion the parvocellular layer of the LGN in the right hemisphere?
a striated (layerd) region-- the first cortical region involved in combining visual information from several sources. It receives information from retinal ganglion cells about the amounts of light falling on them, and about the wavelength of light. This structure transports this information to the striate cortex.
what is the lateral geniculate nucleus?
the structure that performs additional processing of information received form the LGN which it then transmits to the extrastriate cortex
what is the striate cortex
ganglion cells in the retinal PERIPHERY receive input from ____________ photoreceptors while ganglion cells in the fovea (center) receive input from ___________ photoreceptor.
increased sensitivity and maintained high resolution in the fovea which is what the eye is directly focusing on.
what is the result of the 1:1 fovea to photoreceptor ratio?
1:1 ratio between ganglion cells and cones allows for more precise neural imaging
why are cones better at detecting small details?
lower threshold of excitation (very light sensitive)
why are rods better for night vision?
cells in the retina that perform lateral inhibition on bipolar cells around them when exposed to light. They increase neurotransmitter release along bipolar cells along the edges of a discrete light shown to the retina, and decrease NT release on NT's around the edge of light allowing humans to see edges of objects really well because the NT at the edge of light has increased NT release while surrounding neurons have decreased NT release bc horizontal cells are depolarizer by glutamate (in the dark) unlike bipolar cells which are hyper polarized in the dark by glutamate
what are horizontal cells?
it allows you to see edges REALLY WELL so you don't do things like fall of a cliff.
what is the point of lateral inhibition?
there are 3 different receptors (cones) in the eye, with each sensitive to a single hue (blue red and green) and that any color could be accounted for by mixing 3 lights in various proportions
which did the trichromatic theory of color vision argue?
notes that people perceive four primary colors: yellow, green, blue, and red because of negative color afterimages, which suggest that red and green are complementary colors as are blue and yellow.
what did the opponent theory of color vision argue?
when blue is presented the firing rate increases but when yellow is presented the firing rate decreases.
what would happen if you showed blue to the blue on yellow off receptor? what about if you showed it yellow?
the retina has 3 types of photoreceptors. Each cone within the retina uses a different opsin which IS SENSITIVE TO A PARTICULAR WAVELENGTH (blue, red, green), which supports TRICHROMATIC THEORY. A certain color will excite or inhibit the firing of a particular neuron.
How does vision actual work in a way which supports the trichromatic theory of color vision?
at the ganglion cell level, the system responds in an opponent-process fashion, when ganglion cells are excited or inhibited for a prolonged period of time, they later show a rebound effect, firing faster or slower than normal.
How does vision actually work in a way which supports opponent theory of color vision?
after you remove the color stimulus (i.e. you look away) your cells overcompensate, firing at a slower rate than the normal resting potential which the brain interprets as seeing the OFF color. Example, in the red on green off cell, while looking at something red, that cells firing rate is elevated, but when you look away, that cell overcompensates and fires at a slower than normal rate, which the brain then interprets as the inhibiting green off, making you see green.
Explain the rebound effect as it relates to negative afterimages.
an inherited form of defective color vision in which red and green hues are confused; "RED" CONES ARE FILLED WITH "GREEN" CONE OPSION, meaning you see the world in shades of yellow and blue; both red and green look yellowish. Most common form of color blindness
what is Protonopia?
an inherited form of defective color vision in which red and green hues are confused, causing the same symptoms as protanopia but for the opposite reason; "GREEN" CONES ARE FILLED WITH "RED" CONE OPSIN, meaning you see the world in shades of yellow and blue; both red and green look yellowish.
what is Deuteranopia?
An inherited form of defective color vision in which hues with short wavelengths are confused; "blue" cones are either lacking or faulty. This means you have trouble seeing yellows and blues, so you see the world in reds and greens, and blues and yellow look pink. This is considered rare affecting only 1 in 10,000 people.
what is Tritanopia?
-sensory neurons have a background rate of firing (impulses/sec)
-this rate of firing can increase or decrease in response to a stimulus
using micro electrodes to record the firing activity of a single sensory neuron, what was discovered about receptive fields?
some cells fire best to a stimulus of a particular orientation and fire less when orientation is shifted
what is orientation sensitivity within the V1 cortex?
-v2: shape/object recognition
-v2-v4 temporal: form, WHAT?
-v2-v4 parietal: spatial, movement, WHERE?
what do each of the areas within the cortex deal with?
WHAT is the object I am looking at?
The ventral stream (v2-v4 temporal lobe) deals with interpreting...
WHERE is the object I am looking at?
the dorsal stream (v2-v4 parietal lobe) deals with interpreting...
different frequencies, also called the sine wave grating (alternating patches of light and dark). The Low frequency sine wave graphs show large areas of light and dark, and the high frequencies are the sine wave frequencies with very skinny bars denoting fine details.
neurons in the v2 respond best to what?
different neurons are object specific, responding best to specific objects like dogs, or flowers.
neurons in v4 are...
area in v4 and details specifically with facial recognition
-also means that when you look at different objects, it activates different areas of v4
-the more you know about the object, the more "robust"/larger the level of activation experienced.
-It was found that when you showed a person an image of something which they are expert on, the fusiform face area was activated. For example if you show a bird expert a picture of a bird, the fusiform face area will activate as well.
What is the fusiform face area (FFA) and what does it tell us.
Greebles are computer-generated objects that are not associated with any real-life stimulus. But, when people had spent a long time studying and becoming familiar with Greebles, when shown Greebles, the fusiform face area became activated, demonstrating activation of the FFA and expertise.
What are Greebles and what are they used for?
problems identifying objects by sight as the v2-v4 ventral stream leading to the temporal lobe deals with identifying WHAT and object is, so if you have a lesion here, that becomes difficult
what would a lesion in the temporal ventral stream do and why?
-problems identifying location and movement of objects or uncoordinated movement when trying to grasp or pick up an item.
-due to the fact that the v2-v4 dorsal stream leading to the parietal lobe deals with discerning WHERE an object is so if you have lesion here, that becomes difficult.
what would a lesion in the parietal dorsal stream do and why?
inability to recognize faces even those of close friends and family, it is often seen in severe Alzheimer's cases. Visually a person may not recognize you, but may be able to recognize you through audition (sound of your voice). It caused by a lesion in the inferior temporal region.
what is prosopagnosia and what causes it?
Sets with similar terms
Chaper 6: Vision
Chapter 6 vision
The Visual System
PSYC 4800 - Cognition and Perception - E…
Sets found in the same folder
Quiz 1 Physio. Psych.
Quiz 2 Physio Psych
Physiological Psych Chapter 3
Physiological Psych Chapters 4 & 5
Other sets by this creator
MUGN 212 Final Exam
MUGN 212 Final
Chapter 8 Dev Psych
Chapter 7 Dev Psych
Recommended textbook solutions
Myers' Psychology for the AP Course
C. Nathan DeWall, David G Myers
Consumer Behavior: Buying, Having, Being
Michael R Solomon
Myers' Psychology for AP
David G Myers
C. Nathan DeWall, David G Myers