Chapter 5 (final) Flashcards
what makes light, smell, sound or taste special
what we do with it, on its own they are not special
what are Sensations
are features of the environment, like the electromagnetic wavelengths of light or changes in air pressure, creating sound, that we use to create an understanding of the world. Think of sensations as the raw materials of perception
what is meant by sensations are transduced
These sensations are transduced, or translated, by the sensory system into the electrochemical language of the brain.
wha is perception
The brain takes a given message and combines it with previous experience to create a perception. For instance, the sensation of 675 nm of light reflecting from my water bottle is transduced by cells in my eye and my brain uses this information to perceive red - and a water bottle for that matter
ur perceptual world is created by combining two processes, what are they
botton-up and top down processing
what is bottom-up processing,
is the neural processing that starts with the physical message or sensations. This is the early level analysis that prepares the information for use
what is Top-down processing
occurs when we combine this early neural organization with our understanding of the world to interpret and organize that information into something that has value
what do The laws of Gestalt do
aka the Gestalt principles of organization outline some fundamental ways we see the world.
what are the laws of Gestalt
The principle of similarity
principle of closure
principle of good continuation
principle of common fate
what is principle of similarity
states that objects that are physically similar to one another will be grouped together
what is principle of closure
states that people tend to perceive whole objects even when part of that information is missing
what is principle of good continuation
states that if lines cross or are interrupted, people tend to still see continuously flowing lines
what is principle of common fate
states that objects that are moving together will be grouped together
how much of the cortex plays a role in the interpretation of visual information
20%
Light is a form of electromagnetic radiation. Although the spectrum spans from Gamma rays to Radio waves, we are only able to see a narrow band, ranging from around what
400-700 nanometres
From the moment a wave of light enters my eye, the eye actively adjusts its behavior in order to maximize the quality of light that hits the sensory cells in what
the retina
The first obstacle the image must go through is
the cornea
what is the cornea
This outermost, transparent, and protective layer of my eye actually contributes to my ability to focus on the image
Light refracted from the image then enters my eye through;
the pupil
what is the pupil
a hole in the front of the eye that expands and contracts depending on the environment. Because the cells in the back of the eye are sensitive to light, it is important to regulate how much light enters the eye
The size of the pupil is controlled by what
the relaxation or tension in a band of muscles attaching to the Iris
what is The Iris
gives your eyes their color, but does not play a specific functional role in vision
what is accommodation
Behind the pupil, light travels through the lens. This flexible piece of tissue is layered like an onion, and it helps refract light and bring my dog into focus against the sensory cells in my retina. This process is known as accommodation and is determined by the distance between the lens and the object being viewed.
how does accommodation change as something is near or far from you
When an object is close to you, your lens is thicker and rounder, as an object moves further away, muscles attached to the lens relax and the lens elongates
Light then must pass through how many layers of cells in the retina
5 layers
where does the light go after the 5 layers of cells
arrive at the photosensitive cells (the rods and cones) in the back of my eye
what are photosensitive cells (the rods and cones)
this is where light is transduced into cellular activity. This will be the last time the message is in the form of electromagnetic energy. From this point forward, the image will be composed of patterns of neural firing
how do rods and cons work
In the retina, specialized photosensitive cells called rods and cones transduce energy into neural language. This translation is chemically based, as each cell contains a photopigment that is sensitive to light. The chemical reaction caused by exposure to light leads the cell to send a message to the adjacent neurons, and ultimately, a neural impulse is sent to the brain.
what is the fovea
a dense cluster of cones
what do the ones do
These cells respond best when there is a lot of light in the environment. Because only a few cells connect to adjacent ganglion cells, cones also transmit information about fine detail, a process known as visual acuity
how do rods work
Rods are typically sensitive at lower levels of light and thus are the primary cells used for night vision. That is, the rods will generate a neural impulse even when there is only a small amount of light available. This is why it is sometimes much easier to see something in the dark if it falls slightly to the side of center.
what is A second difference between the rods and cones
cones are the only cells that communicate information about the wavelength, perceived as color, of an object. The rods respond only to the amount of light, but do not communicate information about the quality of that light.
After the rods and cones react to light, they send their messages where
to bipolar cells
what do Bipolar cells do
summate the firing of several photoreceptors and send a different kind of message to a ganglion cell. The number and kinds of connections that bipolar cells make are determined in large part by their location
what are diffuse bipolar cells
In the peripheral vision, cells commonly referred to as diffuse bipolar cells can receive messages from as many as 50 rods. Diffuse bipolar cells then summate the experience of the photoreceptors and send a single message to the ganglion cell
what do midget bipolar cells do
receive input from only a single cone, and this message will be sent to a single ganglion cell. This explains the difference in visual acuity across the surface of the retina. While midget bipolar cells in the center receive a large amount of information about the qualities of a single point of light, cells in the periphery receive little information from a much larger area of the retina
Each ganglion cell has a receptive field, meaning what
each ganglion responds to activity only when light falls on a specific portion of the eye and only when specific cells are active
how are The receptive fields of the ganglion cells are often organized
in a center-surround fashion. That is, when light falls on the center of the receptive field, the cell will respond more rapidly, but when the signal falls on the surround part of the receptive field, the cell reduces the firing rate. This allows for a single cell to send a variety of information about the surface of an object.
what do Small ganglion cells do
(often called P cells) receive information from the midget bipolar cells. P cells make up approximately 70% of the cells in the retina and send signals to the brain about qualities of color and detail
what do Larger ganglions do
(M cells) are found in the periphery and receive their signals from the diffuse bipolar cells. These signals send information about motion and visual stimuli in the periphery
the center-surround organization of the ganglion cells helps the brain interpret what
where edges of objects begin and end
The messages finally leave the eye and enter the brain via the optic nerve, made up of the axons of both the M and the P ganglion cells. As a result, there is a spot on the retina where there are no photoreceptors. This creates a small blind spot in each eye; why do we not notice it
it is not noticed because the brain uses information from the other eye and the assumptions about the world to “fill in” the gap
what is the optic chiasm
where the axons from each eye are reorganized for more sophisticated processing. Information from the right side of both eyes is sent to the left hemisphere, while information on the left side of the retina in both eyes is sent to the right side of the brain
the brain’s first interaction with the image itself occurs after this split in what
the Lateral Geniculate Nucleus (LGN) of the thalamus.
what is Visual Striate Cortex
The Visual Striate Cortex, or Visual Cortex (VC), is located in the occipital lobe. Here, important features of the visual world are assembled and identified. We have over 30 areas in the back of the brain dedicated to analyzing and organizing visual information. Throughout this entire pathway, every neuron maintains a spatial organization
This spatial organization is known as what
retinotopic organization
what does retinotopic organization do
is how we maintain a map of the visual world throughout processing
In the Visual Cortex, these points are assembled into lines and edges or features
what are Feature detectors
are specialized cells in the VC that respond most actively to specific stimuli
Using electron recordings of single cells in the visual cortex of their animal participants, researchers identified one type of feature detector known as what
simple cells
how do simple cells work
This cell response to small stationary bars of light oriented at specific angles
how do complex cells work
Complex cells respond most vigorously to vertical lines in motion. As the line moves further from a vertical orientation, the cell will decrease its firing rate
However, even after analysis in the Visual Cortex, my brain is still not done. The information about the image is sent to other regions of my cortex, where I use the assembled visual information to understand still more complex parts of the visual message. Information travels along the what stream
Ventral stream, also known as the What stream, to the temporal lobe. Here, visual information is identified and I know that I am looking at a dog
what is the second pathway
A second pathway, the Dorsal stream or Where pathway, carries visual information to the parietal lobe, where I use the incoming visual information to understand that my dog is to my left and by the door.
The human eye has three types of cones, what are they
One type of cone responds maximally to short wavelengths, which we perceive as blue. Perhaps unimaginatively, these have been named short cones or just S-cones. Similarly, we have medium wavelength cones or M-cones that respond best to greens and long wavelength cones (L-cones) that respond to oranges and reds
what is the trichromatic theory
The trichromatic theory of color vision proposes that color information is identified by comparing the activation of the different cones
Trichromatic theory explains several interesting components of color vision, including colorblindness.
what is colourblindness
On occasion, individuals can be born without one type of cone. For instance, there are two types of Red-Green color blindness. The first, known as Deuteranopia, occurs when “green” cones have “red” photopigment; a second kind of colorblindness, Protanopia, occurs when “red” cones have “green” photopigment. Because the cells respond equally to these two wavelengths, the brain cannot perceive a difference between them
how does the Trichromatic theory explain yellow
it doesn’t really
The cones send their messages where
to the midget bipolar cells and then to the P ganglion cells. The P cells operate slightly differently than the other center-surround organization we have discussed. The P cells will respond vigorously to one wavelength and reduce their firing if they receive a signal indicating a different one. These colors have been paired so that the cell will increase its firing rate if it receives a message from one color and will decrease if it receives a message from another. This creates six colors; red and green are paired, as are blue and yellow and black and white
The brain uses reliable cues to infer information about depth. There are two; what are they
those that require only one eye, or monocular depth cues, and cues that require two eyes, known as binocular depth cues
Monocular cues are also referred to as what
Pictorial Cues, or cues that can be represented on a two-dimensional canvas
what is the cue “Occlusion”
Occlusion occurs when one image partially blocks the view of a second object. The partially hidden object is seen as further away than the whole object
what is the depth cue is known as “Relative Height”
To effectively use this cue, we must also use our knowledge of the horizon. Objects closer to the horizon will appear further away and the greater the distance between the object and the horizon, the closer the object will appear
what is the cue “relative size:
relies on our understanding of the world. According to this cue, when two objects are of equal size, the one that is further away will take up a smaller portion of the retina.
what is the cue “Perspective convergence”
a common cue used in landscapes, and it is a reliable cue for depth. As parallel lines move away from us into the distance, they seem to converge or come closer together
what is the cue of “familiar size”
when we judge distances based on our knowledge of that object size
what is Atmospheric perspective
occurs when more distant objects appear hazy and often have a slight blue tint. This is because as the distance between us increases, the more air particles, dust, pollution and water droplets occupy the space between your eyes and the object
what is the binocular cue retinal disparity
useful cue because as images become farther away, they have a greater degree of disparity on the retinas. The brain calculates depth information by comparing the images on the right and left eyes.
The frequency of the sound is determined by what
the rate of vibrations
what is pitch
We perceive high frequency sounds as having a higher pitch. People can hear frequencies between 20-20,000 Hz, but hear best between 1000 Hz – 5000 Hz - this is also the range of speech.
what is the second dimension of sound “intensity”
A second dimension of sound is the intensity of the wave, which we perceive as loudness. Increased intensity causes the amplitude of the wave to increase and the wave arrives at our ear with more force
Sound enters your ear through what
pinna
what is the pinna
The pinna is the part you pierce and is shaped in such a way that it helps to filter the sound into the ear canal toward the tympanic membrane
what is the tympanic membrane
referred to as the eardrum. The surface of the eardrum works just like the surface of a drum and transfers energy to the three smallest bones in the body, the Ossicles of the middle ear
The ossicles consist of what
the malleus, the incus and the stapes. These bones help to amplify the vibrations as they travel further into the inner ear
The stapes is connected to a small membrane called wat
oval window.
The oval window transfers these vibrations to the bony sound processor of the inner ear called what
the cochlea
what is the cochlea
This is where sound is transferred into the neural language of the brain
Inside the cochlea is a flexible piece of tissue called the what
basilar membrane
what is the basilar membrane
Transduction occurs when the vibrations against the oval window cause fluid inside the cochlea to move. The fluid pushes against thin fibers known as cilia that are attached to the sensory hair cells. Sound causes the basilar membrane to “ripple.” This motion causes the cilia to bend, in turn causing an excitatory message to cascade from the ear to the brain via the auditory nerve
Higher frequencies cause cells to excite cells closest to what
the oval window
lower frequency sounds excite the cells where
deeper in the cochlea
what is place theory
We hear a specific pitch because cells at a specific place on the basilar membrane fire
does place theory explain all about hearing
no
what is frequency theory
Frequency theory states that the brain also uses information related to the rate of cells firing. The more rapidly the cells fire, the higher the perception of pitch
where is the auditory cortex
located primarily in the temporal lobes
wat happens in the Medial Geniculate of the thalamus
Different components of sound are organized and analyzed in the Medial Geniculate of the thalamus. The network from the medial geniculate has several stops, but the majority of information is relayed to the Auditory Cortex in the temporal lobe
Much like the visual system uses the Retinotopic organization, the auditory system maintains what kind of organization
tonotopic organization from the basilar membrane to the auditory cortex
how is The organization of sound hierarchical
with simpler sounds like pure tones being processed in lower regions and more complicated sounds, like human speech, being processed higher up
what are binaural cues
Cues requiring comparisons between information from both ears are known as binaural cues
We use two kinds of binaural cues for sound localization, what are they
Interaural Time Differences and Binaural recording
what is Interaural Time Differences
are comparisons made between the arrival time of a sound in each ear
what is Binaural recording
Binaural uses two microphones, arranged to record sound in the approximate location of human ears
When comparing differences in arrival time between the two ears, we are using which of the following
Interaural time differences
Lee is driving down the street and hears a siren on his left side. He can almost swear it sounds slightly louder to his left ear. It is likely that Lee is using which of the following?
Interaural Level Differences
what is The McGurk Effect
particularly salient example of how visual information can be used to help supplement the sounds coming into our ears
the “ba” and “pa” guy
An object makes contact with the body and the receptor cells embedded in the skin respond, then the message travels up the what
spinal cord to the somatosensory cortex of the parietal lobe.
Most information we gather about texture is derived from the responses of four types of mechanoreceptors located in the skin, what are they
The Merkel receptor and the Meissner corpuscle
Ruffini cylinder and the Pacinian corpuscle
where are the Merkel receptor and the Meissner corpuscle
located close to the surface of the skin and respond to pressure that is applied and then removed
what does The Merkel receptors do
fire continuously as long as the skin is making contact with an objects, sending information about fine details. It is therefore not surprising that there is a high concentration of Merkel receptors in the skin
what do the The Meissner corpuscle do
fires when the skin first encounters the stimulus and when it is removed.
where are the Ruffini cylinder and the Pacinian corpuscle
Located deeper in the skin`
what does the The Ruffini cylinder do
is associated with interpreting the stretching of the skin,
what does the Pacinian corpuscle do
feels vibration and texture
what organizes information from the body
The somatosensory cortex organizes information from the body.
what is somatotopic organization
As we discussed in Chapter 3, there are several maps of your body on the surface of the parietal lobe. Similarly to the visual system, these maps are spatially organized - that is, two adjacent points of contact on your skin map to two adjacent points of neural activity on the cortex
does the brain receive sensory information equally
no, some places (like the hands) are more sensitive
Pain is only adaptive if what
it helps keep the organism alive
The Gate-control model suggests that impulses that indicate painful stimuli can be blocked in the spinal cord by signals sent from the brain. When you are deeply engaged in a physical task like running a marathon or running from a predator, the brain prioritizes mobility over responding to the source of the pain. We are not exactly sure how this is accomplished; however, the gate control model suggests that input happens along three pathways
how many basic senses do we have
We have more than five basic senses, but many of them work so well that we typically take them for granted
what is kinesthetic sense
another sense
basic understanding of where our body is in space and how to move our bodies to accomplish specific tasks. Although our sense of kinesthetics relies quiet heavily on our sense of touch, other receptors are involved as well.
The kinesthetic sense works closely with what
our sense of balance or our vestibular sense
the sensory cells of the vestibular system are located in where
the cochlea
Two structures respond not just to movement but also to what
Two structures respond not just to movement but also to posture and acceleration. The semicircular canals sense changes in acceleration and rotation of the head. The canals are filled with hair cells that respond to the force of gravity. The second organ, called the vestibular sacs, responds to cues associated with a sense of balance and posture
Perception of smell and taste begin with activation of what
chemoreceptors
what is chemoreceptors
These sensory cells respond to properties in air molecules that are interpreted as smell and taste. These two closely related senses are unique; they are the only senses that require you to ingest the physical stimuli in order to analyze the incoming information
Olfactory receptors bind to the cilia of hair cells embedded where
in the olfactory mucosa. This is where odorants will come into contact with the olfactory receptor neurons (ORN). Receptor cells send their messages to the olfactory bulb in the brain. The network becomes more complicated from here as it cascades to various regions of your brain.
The ORNs send their signals to what
glomeruli in the olfactory bulb. These cells consolidate all the messages from a particular receptor type
Where are the olfactory receptor neurons are located
The olfactory mucosa
If you take a moment to look at your tongue in the mirror you will see it is covered with little bumps called what
papillae
we have four categories of papillae what are they
filiform papillae
fungiform papillae,
foliate papillae
circumvallate papillae
what is filiform papillae
which are found over the entire surface of the tongue and give your tongue its “fuzzy” appearance. These are the only papillae that do not contain taste buds
what is fungiform papillae,
On the tips and sides of your tongue, you will see the fungiform papillae, so named because they look like little mushrooms
where are foliate papillae
Along the back of your tongue, you will see little folds these are known as the foliate papillae
what are circumvallate papillae
the circumvallate papillae are found on the back of your tongue and shaped like little mounds.
what is taste pore
Each taste bud contains 50-100 taste sensitive cells, which protrude into a taste pore. Transduction occurs when chemicals bind to the receptor sites on the taste pore. From there, messages are sent not only to the brain, but also to the stomach, as your body begins to metabolically prepare for food
Sensations from both smell and taste are combined where
orbitofrontal cortex (OFC).
why so we think that the OFC contains bimodal neurons,
Sensations from both smell and taste are combined in the orbitofrontal cortex (OFC). This region also receives information from the visual “what” pathway. It is for this reason that we think that the OFC contains bimodal neurons, or neurons that respond to more than one sense
what is the absolute threshold
The absolute threshold is the level of intensity required to create a conscious experience. It is also worth pointing out that the absolute threshold is not absolute. As it turns out, it can be quite different between individuals and circumstances
what is difference threshold
This is the smallest amount of a particular stimulus required for a difference in magnitude to be detected
how small a weight can we add for you to just notice the difference?
what is Weber’s Law.
This principle states that the ability to notice the difference between two stimuli is a constant proportion of the intensity or size of the stimulus. In more simple terms, the more intense the stimulus, the larger the required change to notice a difference
