Perception
What is the goal of the perceiving machine? Example, the Perceptron.
"...learn to recognize similarities between patterns of optical, electrical or tonal info, that is analogous to the perceptual processes of the human brain." (Rosenblatt, 1957)
How did Rosenblatt's Perceptron do?
It did not replicate the process of human perception. It was unable to carry out complex tasks.
Do humans out-perceive computers?
Yes. The computer's problem is that it doesn't have a big storehouse of information that humans begin accumulating as soon as they are born.
What is perception?
The experiences that result from stimulation of the sense.
What is sensation?
Involves simple "elementary" processes that occur at the beginning of a sensory system.
Sensation or Perception?
Light reaches the eye, sound waves enter the ear, or your food touches your tongue.
Sensation
Sensation or Perception?
Identifying the food you're eating and remembering the last time you had it.
Perception
True or False
Deciding what is sensation and what is perception is always obvious?
False
Explain the Perceptual Process.
Steps leading from the environment to perception of the stimulus, recognition of the stimulus, and action with regard to the stimulus.
Example of Perceptual Process.
(1) A tree in the environment
(2) Proximal stimulus, the represensation of the stimulus on the retina
(3) Receptor processing, transduction of perception by receptors
(4) Neural processing, interactions between electrical signals traveling in networks or neurons
(5) Behavioural responses
What is distal stimulus?
Stimulus "out there" in the external environment.
What is proximal stimulus?
Stimulus on the receptors.
What does the principle of transformation state?
Stimuli and responses created by stimuli are transformed between the distal stimulus and perception.
Describe a 2 step example of principle of transformation.
The first transformation occurs when light hits the tree and is reflected from the tree to the person's eyes. As this reflected light enters the eye, it's transformed again as it's focused by the eye's optical system onto the retina.
What does the principle of representation state?
Everything a person perceives is based not on direct contact with the stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person's nervous system.
Distinction between the distal stimulus (step 1) and the proximal stimulus (step 2). Tree example.
It illustrates transformation and representation. The distal stimulus (the tree) is transformed into the proximal stimulus, and this image represents the tree in the person's eyes.
What are sensory receptors?
They are specialized cells that respond to environmental energy, each responding to a specific type of energy.
When the sensory receptors receive information from the environement, what two things do they do?
(1) They transform environemental energy into electrical energy
(2) They shape perception by the way they respond to different properties of the stimuli
What is Transduction?
The transformation of environemental energy (light, sound) into electrical energy.
What is neural processing?
Operations that transform electrical signals within a network of neurons.
The ability to place an object in a category that gives it meaning, is the 6th step in behavioural responses.
Recognition
What was Dr. P diagnosed with and what is it?
Visual object agnosia, it is the innability to recognize objects.
Motor activities in response to a stimulus, is the 7th step to behavioural responses.
Action
True or False.
David Milner and Melvyn Goodale (1995) propose that early in the evolution of animals, the major goal of visual processing was not to create a conscious perception or "picture" of the environemtn but to help the animal control navigation, catcvh prey, avoid obstacles, and detect predators.
True
True or False.
Perception is not a continuously changing process.
False, it is a continuously changing process.
_________ is any information that the perceiver brings to a situation.
Knowledge
An example of how knowledge acquired years ago can influence the perceptual process is your ability to ________ —to place objects into categories.
Categorize
_____________ is processing that's based on the stimuli reaching the receptors. It's also called data-based processing. On the other hand, _____________ refers to processing that's based on knowledge. Also known as knowledge-based processing.
Bottom-up processing; top-down processing
M*RY H*D * L*TTL* L*MB
Is this an example of bottom-up processing or top-down processing?
Top-down processing, because you use yuour knowledge of English words and your familiarity with the nursery rhyme to create the sentence.
Match each column together.
- Physiology - Distal and proximal; steps 1-2
- Behaviour - Perception, recognition, action; steps 5-7
- Stimulus - Receptors & neural processing; steps 3-4
- Stimulus - Distal and proximal; steps 1-2
- Physiology - Receptors & neural processing; steps 3-4
- Behaviour - Perception, recognition, action; steps 5-7
The ________ is that people see vertical and horizontal lines better than oblique lines. Measures both perception and neural responding.
The oblique effect
Match the concepts to their definitions.
(1) Stimulus-behaviour relationship
(2) Grating acuity
(3) Psychophysics
(1) The measure bewteen the physical Ithe stimulus) and the psychological (the behavioural response)
(2) The smallest width of lilnes that participants can detect
(3) The relationship between stimuli and behavioural responses, where behavioural responses can be perception, recognition, or action
(1) and (3)
(2) and (2)
(3) and (1)
_______________, the relationship between stimuli and physiological responses, like neurons firing. Often studied to measure brain activity.
The stimulus-physiological response
David Coppola and coworkers (1998) measured the oblique effect physiologically by presenting lines with different orientations to ferrets. When they measured the ferret’s brain activity using a technique called optical brain imaging, they found that (1)_________ and (2)_________ orientations caused larger brain responses in visual brain areas than (3)_________ orientations
Fill in the blank with the correct type of line.
- Vertical
- Oblique
- Horizontal
(1) Horizontal
(2) Vertical
(3) Oblique
The stimulus-physiological experiment was conducted on both ferrets and humans. Were the results drastically different?
No, the results were similar. Horizontal and vertical orientations resulted in better acuity (behvioural response) and more brain activation (physiological response) than oblique orientations.
The physiology-behaviour relationship is the relationship between physiological responses and behavioural responses. Christopher Furmanski and Stephen Engel (2000) determined this relationship for different grating orientations by measuring brain response and behavioural sensitivity in the same participants.
In their experiement, they decreased the intensity difference betwen light and dark bars until the participant could no longer detect the grating.
Just like the experiment with the ferrets, the participants were able to detect oblique and vertical lines at smaller light-dark differences than for horizontal orientations.
False, they were able to detect horizontal and vertical lines at smaller light-dark differences than for oblique orientations.
Which technique is used for physiological measurements.
- fMRI
- EEG
- PET scan
- Electrodes
- fMRI
In the grating acuity experiment, the absolute threshold was measured for seeing fine lines. What is the absolute threshold?
The absolute threshold is the smallest stimulus level that can be detected.
Complete the definition.
Thresholds are
the minimum stimulus energy needed for an observer to detect a stimulus.
Gustav Fechner proposed that the mind could be studied by measuring the relationship between changes in physical stimulation and person's experience.
He published a book called Element of Psychophysics and in that book, he proposed 3 methods for measuring the threshold and the method of adjustment.
Put together, what are these methods called?
The classical psychophysical methods
True or False.
Fechner's classical psychophysical methods for determining the absolute threshold of a stimulus are the methods of limits, constant stimuli and adjustment.
True, the experimenter presents stimuli in either ascending order (intensity is increased) or descending order (intensity is decreased).
Which definition matches the concept.
Method of adjustment and method of constant stimuli.
(1) The method of limits that different stimulus intensities are presented one at a time. The particiant must respond whether they perceive it on each trial. The most accurate method because it involves many observations.
(2) The participant adjusts the stimulus intensity continuously until her or she can barely detect the stimulus. The faster method because participants can determine their threshold in few trials.
(1) Method of constant stimuli
(2) Method of adjustment
We can also measure the threshold of one stimulus. Example, you already made one batch of stew and you are planning to make a second. You want someone to help you with the salt levels. The _____________ would be applied. It is the smallest difference between two stimuli that enables to tell us the difference between the two.
difference threshold
There are five questions to consider about the perceptual world and the techniques used.
(1) What is the perceptual magnitude of a stimulus?
(2) What is the identity of the stimulus?
(3) How quickly can I react to it?
(4) How can I describe what is out there?
(5) How can I interact with it?
Which technique is used for each of these questions?
- Physical tasks and judgments
- Reaction time
- Recognition testing
- Magnitide estimation
- Phenomenological report
(1) What is the perceptual magnitude of a stimulus?
Technique: Magnitude estimation
(2) What is the identity of the stimulus?
Technique: Recognition testing
(3) How quickly can I react to it?
Technique: Reaction time
(4) How can I describe what is out there?
Technique: Phenomenological report
(5) How can I interact with it?
Technique: Physical tasks and judgments
True or False.
The distinction between physical and perceptual.
Perception is psychology, not physics, and perceptual responses are not the same as the responses of phsyical measuring devices.
True
True or False.
It's important to record from as many neurons as possible because, just as individual people may have different opinions about speech, different neurons may respond differently to a particular stimulus.
True
Electrical signals are recorded from the _______ of neurons using small electrodes to pick up the signals.
axons
True or False.
An axon at -70 mV, the cell is in an action potential. An axon at +40 mV, the cell is at it's resting potential.
False, other way around.
Match the word to it's proper definition.
(1) Propagated response
(2) Spontaneous activity
(3) Refractory period
a) The interval between the time one nerve impulse occurs and the next one can be generated in the axon.
b) The response travels all the way down the axon without decreasing in size
c) Nerve firing that occurs in the absence of environmental stimulation
(1) b
(2) c
(3) a
Neurons swim in a solution containing many ions. Na+, K+ and Cl-.
True or False.
When mixed in water, NaCl will separate its positively charged sodium ions (Na+) from the negatively charged chlorine ions (Cl-).
True
Put the steps of an action potential in the correct order.
(1) When the action potential has passed the electrode, the charge returns to the resting level
(2) Positively charged sodium ions flows into the axon, causing the inside of the neuron to become more positive, the neuron is depolarized
(3) When the axon is at rest, there's no flow of ions, and the record indicates -70 mV resting potential
(4) Positively charged potassium flows out of the axon, causing the inside of the axon to become more negative, the neuron is hyperpolarized
a) 1, 2, 3, 4
b) 4, 2, 3, 1
c) 2, 1, 3, 4
d) 3, 2, 4, 1
d) 3, 2, 4, 1
Match the word to its definition.
(1) Excitatory response
(2) Synapse
(3) Inhibitory response
(4) Receptor sites
(5) Neurotransmitter
a) Small area on the postsynaptic neuron that's sensitive to specific neurotransmitters
b) The neuron becomes depolarized, thus the inside becomes more positive
c) A chemical stored in synaptic vesicles that's released in response to a nerve impulse, has either excitatory or inhibitory effects
d) The neuron hyperpolarizes, the inside becomes more negative
e) A small space bewteen the end of one neuron and the cell of another
(1) b
(2) e
(3) d
(4) a
(5) c
What is sensory coding?
How neurons represent various characteristics of the environment. Ex. the salty neuron. The idea is that one neuron can represent one perceptual experience, like the taste of salt.
What is specificity coding?
The idea that a specialized neuron responds only to one concept/stimulus.
What is the idea behind the grandmother cell?
Neurons could be so highly specific that they fire in response to a specific stimulus, such as a person's grandmother. Jerome Lettvin said that even just thinking of your grandmother could make the cell fire.
What is sparse coding?
Different fron specificity coding, it occurs when a parrticular stimulus fires a small group of neurons. There's evidence that this is represented in the auditory and olfactory systems.
What is population coding?
Our experiences are represented by a large number of neurons firing. An advantage of this of that large groups of neurons can create many different patterns.
Franz Joseph Gall and Johann Spurzheim claimed to observe the correlation between the shape of a person's skull and their abilities and traits (mental faculties), and concluded that there are about 35 different mental faculties that could be mapped out onto different areas of the brain. This is based off the bumps and contours on a person's skull.
What is this called?
Phrenology
The idea that specific brain areas are specialized to respond to specific types of stimuli is called ________, with each specific area called a ________.
modularity; module
Pierre Paul Broca saw a patient with a specific deficit. he could only speak the word "tan", although his speech and comprehension appeared to be intact. After this patient's death, it was shown that he had a lesion in his left frontal lobe.
The area in the frontal lobe important for language perception and production, that when damaged causes difficulty in speaking is known as
Broca's area
The area in the temporal lobe involved in understanding speech, that when damaged, casues difficulty in understanding speech is known as
Wernicke's area
True or False.
Broca's and Wernicke's areas provided early evidence for modularity.
True
True or False.
In fMRI scans, "hotter" colours like red indicate lower activation, while "cooler" colours like blue indicate higher activation.
False. "Hotter" colours indicate higher activation while "cooler" colours indicate lower activation.
Explain the "voice area" of the brain.
In a study, participants were in the fMRI scanner and listened to vocal sounds and non-vocal sounds (environmental sounds). It was shown that the superior temporal sulcus (STS) was activated significantly more to vocal sounds. This is how the "voice area" was given its name.
What is it called when a stimulus causes neural activity in a number of different areas of the brain, therefore, activity is disturbed across the brain?
Distributed representation
What is a good example of distributed representation?
Pain. There is a simultaneous experience when someone touches a hot stove. There is a a sensory component ("it feels burning hot"), an emotional component ("it's unpleasant"), and a reflexive component (pulling your hand away). These different aspects activate different parts of the brain.
Connections between brain areas are important for perception. What is the difference between structural connectivity and functional connectivity?
Structural connectivity is the "road map" of fibers that connect different brain areas. Functional connectivity ius the neural activity associated with a particular function that flows through the structural network.
Going back to brain imaging, when a person is engaging in a specific task, this type of fMRI is called ________. It's also possible to record activity when the brain is not involved in a specific task. This is called ________.
task-related fMRI; resting-state fMRI
Which of the following is not a measure of resting-state functional connectivity.
(1) Uses task-related fMRI to determine a brain location associated with carrying out a specific task (seed location)
(2) Measures the resting-state fMRI at the seed location
(3) Measures the resting-state fMRI at another location (somatosensory test location)
(4)Calculate the correlation between the seed and test location responses
They are all measures of resting-state functional connectivity.
What problem is this?
How do physical processes ike nerve impulses become transformed into the richness of perceptual experience?
The mind-body problem
Larry Hester always had poor eyesight, however, upon seeing an ophthalmologist, he was told that he had a genetic disorder of the eye called _____________.
Retinitis pigmentosa, results in total blindness
Larry had the opportunity to have some of his vision restored. The idea behind the _____________, is to implant electrodes in the back of the eye to send signals to the visual system about what is "out there" in the world. It allows the person to see contrsting lightness vs. darkness, such as the edge between where one object ends and another begins.
bionic eye
Match the correct colour to its corrsponding wavelength.
(1) Green
(2) Yellow, orange and red
(3) Blue
a) Short
b) Medium
c) Long
(1) Green b) Medium
(2) Yellow, orange and red c) Long
(3) Blue a) Short
Light is reflected from objects and enters the eye through the ______ and is focused by the ______ and ______ to form sharp images of the objects on the ______. The network of neurons at the back of the eye contains ______.
(1) Cornea
(2) Retina
(3) Pupil
(4) Photoreceptors
(5) Lens
a) Opening which light is reflected from objects and enters the eye
b) The receptors for vision
c) Transparent focusing element, the first structure light passes as it enters the eye
d) Network of cells that covers the inside back of the eye
e) It changes shape to focus at different distances, this process is called accommodation
pupil; cornea; lens; retina; photoreceptors
(1) Cornea c) Transparent focusing element, the first structure light passes as it enters the eye
(2) Retina d) network of cells that covers the inside back of the eye
(3) Pupil a) Opening which light is reflected from objects and enters the eye
(4) Photoreceptors b) The receptors for vision
(5) Lens e) It changes shape to focus at different distances, this process is called accommodation
The small area on the retina that only contains cone receptors. When looking directly at an object, the image falls directly on the ______.
fovea
The __________ includes all of the retina outside of the fovea, it also contains both rods and cones.
peripheral retina
Clinical condition that causes the degenration of the macula, includes the fovea and a small surrounding area.
Macular degeneration
The lens is able to change its shape to adjust the eye's focus for objects located at different distances. this is achieved by the action of __________.
ciliary muscles
Accomodation is an __________ process. It works so efficiently that most people assume that everything near and far is always in focus.
unconscious
While accomodation can help put things into focus, _________ can affect the ability of the cornea and/or lens to focus incoming light onto the retina.
refractive errors
Match each word to its definition.
(1) Myopia (nearsightedness)
(2) Hyperopia (farsightedness)
(3) Presbyopia
(4) Refractive myopia
(5) Axial myopia
a) The eyeball is too long
b) The inability to see distant objects clearly
c) The cornea and/or lens bends the light too much
d) The inability of the eye to accomodate due to hardening of the lens and the weakening of the ciliary muscles
e) The inability to see near objects clearly
(1) Myopia b) The inability to see distant objects clearly
(2) Hyperopia e) The inability to see near objects clearly
(3) Presbyopia d) The inability of the eye to accomodate due to hardening of the lens and the weakening of the ciliary muscles
(4) Refractive myopia c) The cornea and/or lens bends the light too much
(5) Axial myopia a) The eyeball is too long
Transduction transforms one form of energy into another. Visual transduction occurs in the photoreceptors at the back of the retina, and it transforms ______ to ______.
light; electricity
Visual pigments have two parts: a long protein called ______ and a smaller light-sensitive component called ______.
opsin; retinal
Put these steps in order.
a) Thousands of charged molecules are activated to create electrical signals in receptors
b) The visual pigment molecule absorbs the light, causing the retinal to change its shape (isomerization)
c) An electrical signal has been created, transduction is complete
b) The visual pigment molecule absorbs the light, causing the retinal to change its shape (isomerization)
a) Thousands of charged molecules are activated to create electrical signals in receptors
c) An electrical signal has been created, transduction is complete
Visual adaptation that occurs in the dark, the sensitivity to light increases is known as _____________.
dark adaptation
The sensitivity of the eye when it is in the light-adapted state is known as _____________, whereas, _____________ is the sensitivity of the eye after it has completely adapted to the dark.
light-adapted sensitivity; dark-adapted sensitivity
True or False.
The dark adaptation curve shows that as adaption proceeds, the participant becomes less sensitive to light.
False, as adaptation proceeds, the participant becomes more sensitive to light.
There is a myth that pirates wore eye patches to preserve night vision in one eye so that when they went from the top of the ship to below deck, moving the patch to the light-adapted eye would enable them to see with the dark-adapted eye.
Mythbusters performed tasks with a patch that covered an eye for 30 minutes, and to their surprise, they completed tasks faster with the eye that had been patched.
Why would this work?
It would work because keeping an eye in the dark triggers the process of dark adaptation, which would increase its sensitivity in the dark.
What would need to be ensured to test cone adaptation?
The image of the test ligth must fall only on cones. This is achieved by having the participant look directly at the test light.
How would we measure rod adaptation?
We would need to measure dark adaptation in a person who doesn't have any cones, rod monochromats. It provides us a way to study this adaptation without the interference from cones, since they are more sensitve to light at the beginning of dark adaptation. Once adaptation begins, the rods increase their sensitivity and reach their final level in 25 minutes.
What is the rod-cone break?
The point where vision shifts from cone vision to rod vision.
How come rods take 20-30 minutes to reach their maximum sensitivity compared to cones which takes 3-4 minutes?
Through a process called visual pigment regeneration, it's more rapid in the cones than in the rods. When transduction occurs, the retinal eventually separates from the opsin. When this happens, the opsin causes the molecule to become lighter in process (visual pigment bleaching). When the pigments are in this bleached state, they are no longer useful for vision. For them to transform light energy into electrical energy, the retinal must return to its bent shape and reattach itself to the opsin (visual pigment regeneration). This is dependent on enzymes located in the pigment epithelium.
The relationship between pigment concentration and sensitivity was demonstrated by WIlliam Rushton (1961). He came up with a procedure to measure the regeneration of visual pigment by measuring the darkening of the retina that occurs during dark adaptation.
His measurements showed that it took 6 minutes for cone pigment to regenerate comptetely and 30 minutes for rod pigment.
He found that cone dark adaptation matched the rate of cone pigment regeneration and rod dark adaptation matched the rate of rod pigment regeneration.
What two important connects do these results yield between perception and physiology?
(1) Our sensitivity to light depends on the concentration of a chemical (the visual pigment)
(2) The speed at which our sensitivity increases in the dark depends on a chemical reaction (the regeneration of the visual pigment)
It may happen that something prevents visual pigments from regenerating.
A condition where the retina is detached from the back of the eye?
Detached retina
The differences in the rod and cone responses are measured by the _____________.
spectral sensitivity
To measure sensitivity to light at each wavelength, one wavelength must be presented at a time, _____________. To determine a person's spectral sensitivity, their threshold must be determined.
monochromatic light
The ability to see wavelengths across the spectrum is plotted in terms of ______ vs. wavelength.
sensitivity
The _____________ is measured by having a participant look directly at a test light so that it stimulates the cones in the fovea. The _____________ is measured after the eye is dark adapted and by presenting test flashes in the peripheral retina.
cone spectral sensitivity; rod spectral sensitivity
The _____________ is the shift from cone spectral sensitivity to red spectral sensitivity that takes place during dark adaptation. For example, the red flower turning into the blue flower.
purkinje shift
A pigment's _____________ is a plot of the amount of light absorbed vs. the wavelength of the light.
absorption spectrum
Is the following true?
1. Short-wavelength pigment absorbs light best at 419 nm
2. Medium-wavelength pigment absorbs light best at 531 nm
3. Large-wavelength pigment absorbs light best at 558 nm
Yes
Match each word to its definition.
(1) Ganglion cells
(2) Horizontal cells
(3) Bipolar cells
(4) Amacrine cells
a) A neuron that transmits signals laterally across the retina. They synapse with receptors and bipolar cells
b) A neuron that transmits signals laterally in the retina. They synapse with bipolar cells and ganglion cells
c) A retinal neuron that receives inputs from visual receptors and sends signals to RGCs
d) A neuron that receives inputs from bipolar and amacrine cells. The axons are nerve fibers that travel out of the eye in the optic nerve
(1) Ganglion cells d) A neuron that receives inputs from bipolar and amacrine cells. The axons are nerve fibers that travel out of the eye in the optic nerve
(2) Horizontal cells a) A neuron that transmits signals laterally across the retina. They synapse with receptors and bipolar cells
(3) Bipolar cells c) A retinal neuron that receives inputs from visual receptors and sends signals to RGCs
(4) Amacrine cells b) A neuron that transmits signals laterally in the retina. They synapse with bipolar cells and ganglion cells
_____________ occurs when a number of neurons synapse onto a single neuron.
Neural convergence
What's an important difference between rods and cones?
Signals from the rods converge more than the signals from the cones. This is because there are more rods than cones in the retina.
Is the following true?
1. Rods result in better detail vision than the cones
2. Cones result in better sensitivity than the rods
No.
1. Rods result in better sensitivity than the cones
2. Cones result in better detail vision than the rods
Is the following true about convergence?
High convergence results in high sensitivity but poor acuity (the rods). Low convergence results in low sensitivity but high acuity (the cones).
Yes
H. Keffer Hartline won the Nobel Prize in 1967. He illuminated different areas of the retina and found that the cell he was recording responded only when a small area was illuminated. He called the area that caused a neuron to fire the ganglion cell's ______________.
receptive field
True or False.
Shining light on a particular point on the retina activates many ganglion cells.
True, because ganglion cells cover a big area, meaning many receptors.
Stephen Kuffler (1953) measured gnaglion cell receptive fields. Ganglion cells have center-surround receptive fields.
The center can be excitatory (+) with an inhibitory surround (-). Or can have an inhibitory center (-) with an excitatory surround (+).
Define these.
(1) Excitatory area
(2) Inhibitory area
(3) Excitatory-center, inhibitory surround
(4) Inhibitory-center, excitatory surround
(1) Stimulation of this area causes an increase in nerve firing
(2) Stimulation causes a decrease in nerve firing
(3) The center causes an excitatory response while the surround causes an inhibitory response
(4) The center cause in inhibitory response while the surround causes an excitatory response
What kind of response is this?
1. A small response to a small dot in the excitatory center
2. Increased response, the whole excitatory area is stimulated
3. Response begins to decrease when the size of the spot is increased to the point where it reaches the inhibitory surround
4. Coverage of the entire inhibitory surround
Center-surround antagonism
In the retina, _____________ is transmitted by the horizontal and amacrine cells.
lateral inhibition
The Limulus eye has been used for research on lateral inhibition because its receptors are very large so stimulation can be applied to individual receptors. The eye is made up of hundreds of tiny structures called ______.
ommatidia
An increase in perceived contrast at borders between regions of the visual field is known as _____________.
edge enhacement
Honeybees have a visual pigment that absorbs light all the way down to ___ nm. This very ____________ pigment enables the honeybee to perceive UV wavelengths that are invisible to us.
300; short-wavelength
An infant isn't able to explicitely respond if they perceive or don't perceive something. A method used to measure infant visual acuity is called the _____________. Two stimuli are presented, and the infant's looking behaviour is monitored for the amount of time the infant spends viewing each stimuli.
preferential looking technique
Is the following true.
Infants do not prefer to look at stimuli that is homogenous. Ex. a grating stimulus.
False, they prefer stimuli that is homogenous. If the grating bars decreased, it would make it more difficult for the child to discriminate with is the grating stimulus and what's a gray stimulus.
An electrical response to visual stimulation recorded by the placement of disk electrodes on the back of the head, is known as _____________. This is placed on an infants head.
visual evoked potential
Is this statement true.
The VEP usually indicates better acuity than does preferential looking, but both techniques indicate that visual acuity is poorly developed at birth.
True
Is the following true.
During the Russo-Japanese War, Japanese physician Tatsuji Inouye treated soldiers who survived gunshot wounds to the head. However, he noticed that if a soldier had a wound on the back of his head, his vision was impaired. Also,the area of the head that was injured correlated with the area of vision he lost. Ex., visual impairements on the left side of the brain were noticeable when there was a bullet wound on the right side of the brain.
True
What is the name of the location where an x-shaped bundle of fibers, that when activated by stimulation on one side of the brain, crosses over to the other side of the brain?
The optic chiasm
The result of crossing is that all fibers corresponding to one side of the visual field, ends up on the other side of the visual field. This way, each hemisphere responds to the _________ side of the visual field.
contralateral
Fill in the blank.
After meeting at the optic chiasm and crossing to the contralateral hemisphere, approximately 90% of the signals from the retina proceed to the _____________, located in the thalamus, while the other 10% travel to the _____________, the structure involved in controlling eye movements.
lateral geniculate nucleus (LGN); superior colliculus
Fill in the blank.
From the LGN, the visual signal travels to the occipital lobe, the _____________, where signals from the retina and LGN first reach the cortex. This area is also called the striate cortex or area V1.
visual receiving area
True or False.
The receptive field is never on the receptor surface, it is further back.
False, the receptive field is on the receptor surface, the retina
A neuron in the visual cortex that responds best to bars of a particular orientation is known as a _____________. the relationship between orientation and firing is indicated by a neuron's orientation tuning curve. However, unlike these types of neurons, _____________ respond only when a correctly orientated bar of light moves across the entire receptive field.
simple cortical cell; complex cells
_____________ fire to moving lines of a specific length or moving corners/angles.
End-stopped cells
The idea behind _____________ is that firing causes neurons to eventually become fatigued or adapt.
Causes two physiological effects:
(1) The neuron's firing decreases
(2) The neuron fires less when that stimulus is immediately presented again
selective adaptation
The intensity difference between two areas that can just barely be noticed, is known as the _____________.
contrast threshold
The idea that if an animal is reared in an evironment that only contains certain types of stimuli, then these neurons responding to the certain stimuli become more prevalent.
Selective rearing
The capacity of the nervous system to change in response to perceptual experience is known as _____________.
neural plasticity
True or False.
Adaptation is a long-term effect and selective rearing is a short-term effect.
False, adaptation is a short-term effect and selective rearing is a long-term effect.
the adjacent location columns working together to ceover the entire visual field is known as ______.
tiling
______ is the removal of an area of the brain. Usually donein experiments on animals to determine the function of a particular area.
Ablation
True or False.
Although there's good evidence that the ventral and dorsal pathways serve different functions, it's important to note that
(1) the pathways are not totally separated but have connections between them
(2) signlas flow not only "up" the pathway from the occipital lobe towards the parietal and temporal lobes, but also "back" as well
True
_____________ is an area of the brain outside of V1, involved in object perception and facial recognition.
Inferotemporal (IT) cortex
The subcortical structure in the brain that's associated with forming and storing memories.
Hippocampus
Structures like the parahippocampal cortex, the entorhinal cortex, and the hippocampus, make up what's called the _____________.
medial temporal lobe (MTL)
The change in response to a stimulus presented within a neuron's receptive field caused by stimulation outside of the receptive field is known as _____________.
contextual modulation