Psych 370 final

What is the doctrine of specific nerve energies?

We perceive the action of our neurons, not the world directly; No matter how a neuron is stimulated, the rest of the nervous system will interpret its activation the same way

Which is a cranial nerve with a sensory function?

Olfactory nerve

What is the neuron doctrine?

The principle that nervous system is made up of individual cells

What is the spike initiation zone?

The part of the neuron where the action potential originates

What is the main (most common) excitatory neurotransmitter of the nervous system?

Glutamate

What is temporal summation?

When Neuron A releases a lot of bursts of neurotransmitter onto Neuron B over time, so Neuron B responds more

What is spatial summation?

When Neuron B is receiving information from several axon terminals at once, so Neuron B responds more

Does perception of a stimulus occur simultaneously with (at the same time as) sensation of the stimulus?

No. It takes time to pass the signal up to the Central Nervous System.

What is a typical definition of absolute threshold?

The lowest stimulus intensity that a subject reports detecting 50% of the time it is present

How is the method of constant stimuli different than the method of adjustment?

It presents stimuli in a random order

Which variables may affect a test subject’s response criterion?

Incentives (positive or negative),Attention levels,Familiarity with the stimulus,Noise (or a lot of other stimuli) in the environment,All of the above

false:

If a stimulus is sensed, it will be perceived.

false

If something is perceived, a stimulus was present.

What is the difference between white matter and gray matter?

White matter is collections of axons; gray matter has cell bodies, dendrites, synapses, and axons

When we say that nervous system is ‘electrical’, what do we mean?

Ions flow across membranes, setting up voltage differences

True

Perception typically happens in the brain

True

Perception is highly dependent on context and personal variables

Weber’s Law states that:

As the intensity of the stimulus increases, the amount of change required to detect a difference also increases

What are some factors that can influence sensitivity to a stimulus?

The intensity of the signal,The capacity of sensory systems,Random neural firings and other “internal noise”,The amount of background stimulation, or “external noise”, All of the above

A highly specific test (or test subject) will:

Tend to only detect a stimulus when it is actually present

What sensory attribute does wavelength of light give rise to?

Color

Visible light is sub-spectrum of wavelengths on the:

Electromagnetic spectrum, which also includes x-rays, radio waves, UV, and microwaves

False

All animals have the same visible light spectrum, meaning they all see the same wavelengths of light.

What is a pigment?

A substance which differentially absorbs certain wavelengths and reflects others

True

Objects greater than ~25 feet away are focused by default; the further away an object is, the more parallel the rays of light coming from it will be when they enter the retina.

What is presbyopia?

A result of hardening of the lens (so it cannot change shape) that occurs with age

Which is NOT true of the fovea?

It has a 6:1 ratio of cones to rods

Why do we have a blind spot in each eye?

Where the blood vessels and axons exit/enter the eye, there are no photoreceptors

Why don’t you notice your blind spot in everyday life?

You have two eyes; each eye can see in the blind spot area of the other, The blind spot is not in the fovea, and attention is usually focused on the fovea, The brain infers what should be in the spot, and fills it in with a perception, All of the above

Together, rods and cones can also be called:

Photoreceptors

Scotopic vision is:

Black-and-white

Cones can “see color” and rods can’t because:

There are three different types of cones and only one type of rod

What is true of cones?

They have less convergence than rods

Rods and cones are densely packed with:

Membraneous discs

If I want to see an object with high acuity, I should:

Foveate it

Photoreceptor cells release neurotransmitter on to:

Bipolar cells

True

My vision is awesome, and I’m excited to learn more!

Babies have poorer vision than adults in part because at birth, their:

Cones are poorly developed

Photoreceptors are full of membranous discs because:

Opsin proteins are lipophilic and must be embedded in membranes

When is a photoreceptor cell releasing the highest amount of glutamate?

In dark conditions

Across all your rods and cones, how many different types of opsins do you have?

four

When retinal absorbs the energy of a photon, it:

photoisomerizes

False

Glutamate always excites (turns on) bipolar cells.

Which is true of convergence?

It refers to many presynaptic cells all communicating with a single postsynaptic cell

The term “receptive field” in vision refers to:

The area of a visual scene that influences the activity of a neuron

Horizontal cells release which neurotransmitter?

GABA

Imagine a dark dot on a light background in the receptive field of a bipolar cell. How much neurotransmitter will the bipolar cell receive?

A lot!

With Mach bands, the boundary between contrasting shadings can appear exaggerated because of:

Lateral inhibition in the retina

Which cells unbleach the fastest?

Cones

During dark adaptation…

There are two phases: ~5 minutes of rapid improvement followed by ~30 minutes of slower, but more dramatic improvement

The spectral sensitivity of rhodopsin is:

Between that of a short wavelength cone opsin and a medium wavelength cone opsin

Afterimages occur because:

Cells that respond to the wavelengths will have all their opsins bleached out

If you stare at a big blue Y, what color will the afterimage Y be?

yellow

Magenta is considered a “non-spectral color” because:

It’s the brain’s interpretation of activity of short- and long- wavelength cones together

Cataracts are:

Crystals forming in the lens

Glaucoma is:

Damage to the optic nerve

The axons of retinal ganglion cells make up the

Optic nerve

The axons of retinal ganglion cells synapse in the:

Thalamus

Most colorblindness is the result of:

A mutation of the medium or short wavelength cone opsin

True

The brain will make further modifications to the visual signal before it is processed for perception.

False

ALL fibers (axons) in the optic nerve synapse in the lateral geniculate nucleus of the thalamus

Koniocellular cells in the lateral geniculate nucleus process information related to:

Color

Layers 1 and 2 of the lateral geniculate nucleus:

Process information related to movement

Layer 3 of the RIGHT LGN carries information from which eye(s)?

Right

What does retinotopy refer to?

Information that is processed in neighboring parts of retina is also processed in neighboring parts of visual cortex

ALL cells in primary visual cortex seem to have a preference for:

Angle of a bar of light

Selective adaptation occurs when:

A cell is sensitive to a particular feature in the visual field, and if it is exposed to that feature for long enough, it will adapt and respond less for a brief period

What is interocular transfer of an illusion effect evidence of?

The illusion is occurring in the brain, not the retina

Imagine you are a professor and teaching a class in a large classroom. You quickly scan the class to monitor attendance. Later, you are carefully looking around the class to judge facial expressions—are my students understanding? Which feature detectors are you using for these two tasks?

First, low spatial frequency detectors; second, high spatial frequency detectors

Animals reared during a ‘critical period’ in environments with mostly vertical lines will:

Develop more sensitivity to vertical lines

Which best describes the concept of distributed coding?

A pattern of activity across many neurons represents an object

True

a typical sensory pathway, coding tends to start out “specific” and become “distributed” later in the pathway.

Which best describes cortical magnification?

Proportionately more cortical space is dedicated to the fovea

Primary visual cortex is arranged into columns. The largest of these are:

Location columns

What is the name of the structures in primary visual cortex that are thought to process color?

Blobs

Ocular dominance columns refer to the arrangement of cells:

Getting more input from one eye over the other

Which is NOT true of the dorsal pathway?

If it is damaged, one possible symptom is prosopagnosia

What are some reasons why color vision is important?

Aesthetic appreciation,Survival through object identification,Perceptual grouping,All of the above

“White” light:

Has generally equal amounts of all visible wavelengths

True

A pigment can only reflect wavelengths that are supplied by the illuminant.

What is saturation of a color?

Amount of white light in it

The cortex gets information from three cone types, but further processes the information into two comparison streams. These are:

(M+L) – S and (M-L)

“Assuming the illuminant” refers to the brain

Subtracting out wavelengths that seem to be overrepresented in the light source

Cerebral achromotopsia refers to:

Damage to ventral occipitotemporal lobe and symptoms of loss of color vision

What is the ‘binding problem’?

Different features of the visual scene are processed by different parts of cortex; the brain must unite them for perception

What is the ‘inverse projection problem’?

There are an infinite number of objects that could create a particular image on the retina

What is the ‘viewpoint invariance’?

While objects can look dramatically different from different viewpoints, we can generally still recognize them

The Gestalt psychologists believed:

That perception is greater than the sum of sensations

In the image to the left, you are likely to see two triangles overlapping three circles because of:

Illusory contours

What is ‘pragnanz’?

Assuming the simplest possible structure

What is the gestalt grouping principle that best explains the figure above?

Good continuation

Whether you perceive a picture of a surface texture as being bulges or indentations can change depending on how the picture is oriented. Why?

Light-from-above heuristic

Which is NOT true of how your brain perceives figure vs. ground?

The contour separating figure from ground ‘belongs’ to the ground

Which is a common heuristic for differentiating figure from ground?

Whatever is completely surrounded is figure

Which is not a category of depth cues?

Photopic cues

false

If your eyes converge to look at an object, it means the object is further away.

If an object is more than ~20 feet away:

Focused on the retina by default

How big an object seems to be depends on:

How much of the retina it takes up,Pre-existing knowledge of the object,Depth cues,All of the above

The size-distance scaling equation shows that as you move away from an object you are looking at:

the retinal size gets smaller but the distance perception gets bigger, and the perceived size stays the same

What is Emmert’s Law?

The perceived size of an after image depends on the distance of the surface on which the after image is viewed