Biopsychology Exam 2

Front 1

Retina

Back 1

-rear surface of the eye
-lined with photoreceptors

Front 2

Lens

Back 2

-bends in response to contraction of ciliary muscles, in order to focus the image on the retina
-makes minor adjustments in the image

Front 3

Fovea

Back 3

-part of the retina with the greatest ability to resolve detail (sharpest detail)
-no vasculature
-tightly packed receptor cells
-reduced number of other cells
-light goes directly to the receptor cells without having to pass through other things
-each receptor contacts a single bipolar cell, which then contacts a single ganglion cell, which sends one axon to the brain, thus: each receptor has its own line to the brain
-our fovea is focused ahead; a hawk's or an owl's is focused downward; a mouse's is focused upward

Front 4

Blind Spot

Back 4

-formed by the optic nerve
-area of the retina that lacks receptors
-we actively fill in the blind spot

Front 5

Optic Nerve

Back 5

-contains axons of ganglion cells and carries information out of the eye and to the brain
-goes to the lateral geniculate nucleus, superior colliculus, etc.

Front 6

Receptors

Back 6

-sensory receptors use receptor potentials to transduce a stimulus
-all receptors contain photopgments, which release energy when struck by light

Front 7

Receptor Potential

Back 7

-voltage difference between the inside and the outside of the cell that results from receiving a stimulus
-types:
1. graded with a stimulus
2. passive
3. local

Front 8

Transduce

Back 8

-to turn one type of energy into another
-receptors turn various stimulus energies into electricity

Front 9

Flow of Information in the Eye

Back 9

1. visual receptors transduce light energy
2. receptors modulate the activity of bipolar cells
3. bipolar cells send information to the ganglion cells
4.ganglion cells send information to the brain
5. activity in these cell types is further modulated by horizontal cells and amacrine cells

So: light → receptors → bipolar cells → ganglion cells → brain

Front 10

Cones

Back 10

-4 million
-most abundant in the fovea, and get less and less compact as move toward the periphery
-respond best to bright light
-responsible for color vision (because of the types of photopigments)
-each cell has only one photopigment, but three types in cones
-ratio of cones to bipolar cells closer to 1:1

Front 11

Rods

Back 11

-100 million
-most abundant in the periphery
-respond to low levels of light
-not very useful in bright light
-have one type of photopigment
-very sensitive, and thus easily saturated
-rods have poor resolution; pool resources → give only general area
-when in low light, put object of interest in periphery
-multiple rods share one bipolar cell, so pixelated perception

Front 12

Trichromatic Theory of Color Vision

Back 12

-primary light colors are: red, green, and blue
-behavioral evidence: human subjects can match any perceived color by matching 3 individual wavelengths
-physiological evidence: there really are 3 different types of cone cells that each respond maximally to different wavelengths of light (called high/long, medium, and low/short)
-however, they each respond to a range of light wavelengths and the peaks are not exactly what was predicted by the original trichromatic theory

Front 13

Opponent-Process Theory of Color Vision

Back 13

-the brain perceives light according to 3 opponents:
1. white to black
2. red to green
3. blue to yellow
-behavioral evidence: subjects report negative after-images according to these opponents
-physiological evidence: bipolar cells are excited by one wavelength and inhibited by another along these scales

Front 14

Color Constancy (Other Theories of Color Vision)

Back 14

-ability to perceive colors as constant despite changes in illumination
-example: know that something partly covered in shadow is still the same color

Front 15

Retinex Theory (Other Theories of Color Vision)

Back 15

-states that the cortex compares information from various parts of the retina and then adjusts the perception of color and brightness for each area of the visual field

Front 16

Central Processing of Visual Information: The Basics

Back 16

-rods/cones send information to the ganglion cells
-ganlion cells send information to:
1. lateral geniculate nucleus of the thalamus
2. superior colliculus
3. other areas of the thalamus
-the lateral geniculate nucleus sends information to:
1. other parts of the thalamus
2. the visual cortex
-the visual cortex sends information to:
1. other areas of visual cortex
2. back to the thalamus
-left half of brain processes right half of world and vice versa, but each eye sees both, so split each image into two halves

Front 17

VIsual Field

Back 17

-part of the world that can be seen at any given time
-there is a right visual field and a right visual field
-these refer to the center of the person: the right visual field = right side of the person

Front 18

Receptive Field

Back 18

-part of the visual field that any given neuron "sees" or responds to
-each neuron has a receptive field that is some part of the visual field

Front 19

Early Processing

Back 19

-processing starts to get complex early on, at the level of the ganglion cell:
1. some ganglion cells are on-center: excited by stimuli in the center of their receptive field
2. some ganglion cells are off-center: inhibited by stimuly in the center of their receptive field
-there are overlapping receptive fields, which allows for great detail because huge difference in signalling based on a very small difference in distance/placement

Front 20

On-Center

Back 20

-ganglion cells that are excited by stimuli in the center of their receptive fields

Front 21

Off-Center

Back 21

-ganglion cells that are inhibited by stimuli in the center of their receptive fields

Front 22

Rods/Cones excite two "sets" of cells:

Back 22

1. bipolar cells (sometimes via amacrine cells)
2. horizontal cells

Front 23

Bipolar Cells

Back 23

-send information further up the line to the ganglion cells, etc.

Front 24

Horizontal Cells

Back 24

-are responsible for sharpening contrasts through lateral inhibition

Front 25

Lateral Inhibition

Back 25

-horizontal cells can inhibit a wide stretch og bipolar cells
-as a result, activity in one bipolar cell is associated with inhibition of its neighbors
-the inhibition of neighbors results in a sharpening of contrasts at the edges of a stimulus
-so can get" moderately excited, really excited, moderately inhibited, and really inhibited

Front 26

Types of Primate Ganglion Cells

Back 26

1. Parvocellular
2. Magnocellular
3. Koniocellular

Front 27

Parvocellular

Back 27

-small cell bodies and receptive field
-located mostly near the fovea (have private lines from the cones)
-detect visual details
-highly sensitive to color
-connect to lateral geniculate nucleus of the thalamus

Front 28

Magnocellular

Back 28

-large cell bodies and receptive fields
-located throughout the retina (widely dispersed
-detect motion and patterns
-insensitive to color
-connect to lateral geniculate nucleus of the thalamus and other areas of the thalamus

Front 29

Koniocellular

Back 29

-small cell bodies and receptive fields
-located throughout the retina
-various functions (least well-known)
-connect to lateral geniculate nuclues of the thalamus and other areas of the thalamus and superior colliculus

Front 30

Primary Visual Cortex = V1

Back 30

-responsible for the first stage of cortical processing
-responds to any kind of visual stimulus and is active during visual imagery (imagination)
-V1 sends information to V2

Front 31

V2

Back 31

-responsible for further processing
-responds to particular forms and illusory contourr, which are perceived visual stimuli that are not actually there
-one V2 for dorsat half of world and another for ventral half
-after V2, the parvocellular and magnocellular cortical projections split off

Front 32

Cortical Pathways

Back 32

-after V2, magnocellular and parvocellular cortical projections split off:
1. one pathway, mostly carrying information from the parvocellular pathway, is sensitive to the details of shape
2. one pathway, mostly carrying information from the magnocellular pathway, is sensitive to movement and is important for integrating vision and action
3. one pathway, with mixed parvocellular and magnocellular information, is sensitive to brightness and color (identifying characteristics of an object
-the parvocellular pathway is othersise known at the what pathway (identity of object)
-the magnocellular pathway is otherwise known as the where pathway (location of object in space)
-it seems that these may actually be split at the level of the ganglion cell input, even though it seems input is the same going into V2

Front 33

What and Where Experiment

Back 33

-Ungerleider and Mishkin (1982)
-Monkeys perform two different short-term memory tasks, each dependent on either remembering "what" or "where"
-"what" task is object discrimination
-"where" task is landmark discrimination
-both dorsal (where) and ventral (what) pathways branch out from V1

Front 34

Object Discrimination (What)

Back 34

-monkey is shown one object
-after some short delay, the monkey is given a choice between two objects
-it must choose the object previously seen
-has difficulty remembering what is shown if temporal area/ventral pathway is removed, but can perform where task

Front 35

Location Discrimination (Where)

Back 35

-monkey is shown a landmark and a corresponding relative location of food
-after some short delay, the monkey is given a choice between two locations
-it must choose the location previously seen
-has difficulty remembering where if the parietlal cortex/dorsal pathway has been removed, but can perform what task

Front 36

Cortical Cell Types: Method

Back 36

-measure action potentials and find out what receptive fields are
-projection on screen → cat → microelectrodes hooked up → amplifier → oscilliscope → record of response (neural spikes)

Front 37

Cortical Cell Types

Back 37

1. SImple Cells
2. Complex Cells
3. Hyper-Complex Cells

Front 38

Simple Cells

Back 38

-contained in V1
-receptive field has a single, fixed excitatory portion and an inibitory surround (have a very simple thing that they like
-shape of the excitatory or inhibitory portions are different for different simple cells
-most respond to bars or line, or areas near bars or lines
-highly sensitive because they will pick out orientation and direction of line they will respond to

Front 39

Complex Cells

Back 39

-get their input from the simple cells (one synapse down)
-contained in both V1 and V2
-receptive fields cannot be mapped into fixed excitatory and inhibitory zones (like complicated things)
-example: one type responds to a particular orientation (like a simple cell), but does so regardless of location within the receptive field (unlike a simple cell)
-"I like rectangles, but I don't care where they are"

Front 40

Hyper-Complex Cells

Back 40

-cells that are more complex than complex cells
-that is, they contain all of the features of complex cells, plus at least one more
-typically, the added feature is an area of strong inhinbition
-"I like rectangles no matter where they are except for here"
-exclusionary logic → high levels of processing

Front 41

Cortical Columns

Back 41

-cells are organized into columns in the cerebral cortex
-cells within a single column typically have the same characteristics (shape of excitatory field, motion sensitivity, etc.)
-usually respond to either left or right eye (called Ocular Dominance)

Front 42

Spatial Frequency Filter Model

Back 42

-V1 cells are sensitive to gratings of a particular frequency; each cell likes a different frequency and frequency can be used to recognize an object
-spatial frequency is the number of light and dark (or color) cycles per degree of visual space
-perhaps the CNS has different spatial frequency channels for analyzing visual data
-visual cortex uses calculus to extract series of sine waves from complicated waveforms
-evidence: V1 does contain cells that are responsive to particular spatial frequencies and subjects do adapt to particular spatial frequencies

Front 43

Shape Analysis

Back 43

-in V2, which is responsible for shape perception, some cells respond to particular patterns of stimulation: line conjunctions, circles, etc.
-in V4, many cells respond to dimensions/depth

Front 44

Disorders of Object Recognition

Back 44

1. Visual Agnosia
2. Prosopagnosia

Front 45

Visual Agnosia

Back 45

-inability to recognize objects
-typically, the patient can describe the features of an object, but cannot name the object

Front 46

Prosopagnosia

Back 46

-inability to recognize faces
-the fusiform gyrus may be specialized for face recognition: cells there respond to a variety of stimuli, but respond most strongly to faces

Front 47

Mechanical Sensation

Back 47

-includes audition, vestibular sensation, and somatosensation
-a sense for which the receptor cells are physically distorted by the stimulus (mechanical pressure from energy of the real world)

Front 48

Chemical Sensation

Back 48

-includes gustation and olfaction
-a sense for which the receptor cells detect chemical(s) in the stimulus (chemical components from real world act on chemical receptors on sense cells)

Front 49

Parts of the Ear

Back 49

1. Outer Ear
-Pinna = the eat
2. Middle Ear
-tympanic membrane (eardrum)
-middle ear bones: transmit vibration from eardrum to Oval Window
3. Inner Ear
-the cochlea
-contains a fluid that is displaced when the oval window vibrates, which then displaces hair cells

Front 50

Characteristics of Auditory Stimuli

Back 50

1. Amplitude: intensity of a soundwave, measured in dB
2. Frequency: compressions (cycles) per second, measured in Hz
3. Loudness: perception of amplitude/intensity
4. Pitch: perception of frequency

Front 51

Theories of Auditory Processing

Back 51

1. Frequency Theory
2. Place Theory
3. Combined Theory

Front 52

Frequency Theory (of Auditory Processing)

Back 52

-basilar membrane vibrates in synchrony with the stimulus
-auditory axons produce action potentials at the same frequency
-pitch is derived from action potential freqeuncy
-problem because frequency of hearing goes beyond frequency of action potential firing ability
-at higher frequencies, a bunch of cells combine efforts to keep up with the stimulus (Volley Principle)

Front 53

Place Theory (of Auditory Processing)

Back 53

-different parts of the basilar membrane vibrate at different frequencies
-the vibrating part produces action potentials
-pitch is derived from action potential origin (in cochlea)
-so not how many APs, but where they come from

Front 54

Combined Theory (of Auditory Processing)

Back 54

-at low frequencies, system uses frequency/volley
-at higher frequencies, system uses place
-in between, uses in between (500-5000 Hz)

Front 55

Hair Cells

Back 55

-lie in the cochlea and are mechanically displaced when the fluid in the cochlea moves
-when processes on the hair cell are displaced, ion channels in the membrane open up and let K into the cell
-this works because cochlear fluid has high K concentration on outside, so it wants to get into hair cells (not like in neurons where it is leaking out)

Front 56

Auditory Information

Back 56

-is bilateral above the level of the inferior colliculus

Front 57

Primary Auditory Cortex

Back 57

-located in the temporal lobe
-some cells in the PAC have spatial receptive fields
-some cells in the PAC have frequency receptive fields
-damage to PAC does not cause deafness, but does injure ability to recognize combinations or sequences of sound (such as music or speech)

Front 58

Conductive Deafness

Back 58

-middle ear deafness
-failure in transmission in the bones of the middle ear
-caused by disease/infection or malformation of the bones of the inner ear
-can be somewhat alleviated by hearing aids

Front 59

Nerve Deafness

Back 59

-inner ear deafness
-failure in cochlea, hair cells, or auditory nerve
-caused by disease or prenatal problems
-can be somewhat alleviated by hearing aids
-also, cochlear implant where you insert electrodes

Front 60

Sound Localization

Back 60

1. Interaural intensity difference
-best for high frequencies
2. Interaural timing difference
-especially for stimuli with quick onset, because arrives at one ear before the other
3. Interaural phase difference
-best for low frequencies, because at higher frequencies, harder to distinguish different points
-only works at particular angles

-none of these works particularly well for sounds that come from right in front or in back of us

Front 61

Vestibular Sensation

Back 61

1. vestibular organ:
-2 otolith organs
-3 semicircular canals
2. otolith: "ear stone"
-small calcium carbonate particles
-otolith measures head tilt
-how? rocks displace hair cells, and brain knows angle of tilt
3. semicircular canal:
-contains fluid and hair cells (like in cochlea)
-measures head acceleration

Front 62

Taste Receptors

Back 62

-hybrid skin cells that are similar to both neurons and skin cells
-excitable, release transmitter
-high turnover (replaced with high frequency)
-first cells in chain do not produce APs, but do respond to graded potentials and release transmitter

Front 63

Types of Taste Receptors

Back 63

1. Salty
2. Sour
3. Sweet
4. Bitter
5. Umami

Front 64

Salty Receptors

Back 64

-receptors have Na channels that are relatively permeable to the sodium contained in salt (Na just leaks in)

Front 65

Sour Receptors

Back 65

-receptors have K channels that have binding sites for acids
-binding closes the channel, which prevents K from leaking out, thus increasing the potential

Front 66

Sweet, Bitter, and Umami Receptors

Back 66

-receptors have specialized binding sites that are coupled to metabotropic mechanisms (G-proteins)

Front 67

Taste Perception

Back 67

-there are only 5 primary tastes that we know of
-to distinguish between different stimuli, the brain must compare responses of a large number of receptors
-the integration begins at the first cell (the target of the receptor cells)

Front 68

Taste Nerves

Back 68

-project to the nucleus tractis solitarius (solitary nucleus or NTS) in the medulla
-NTS projects to:
1. Cortex
-insular cortex (primary taste cortex, aka G1)
-primary somatosensory cortex (somatosensation)
2. hypothalamus and amygdala (emotion and motivation)
-helps determine the emotional valence of the stimulus, ex. taste aversion

Front 69

Olfaction

Back 69

-receptors are the olfactory cells of the olfactory epithelium
-epithelium, bulb, cortex, are organized topographically (like the nose has a map of chemical world)
-each receptor cell has only one type of receptor molecule
-mechanism is metabotropic
-humans have hundreds (about 700) of different receptor proteins, whereas rats have thousands
-smell is the sense that we have the widest variety of receptors for!

Front 70

Olfaction: Pheremones

Back 70

1. pheremone receptors respond to: chemicals that are released by animals that are designed to affect the behavior of other members of their species
2. pheremone effects
-female secretions promote synchronization of cycle
-male secretions promote regularity of cycle
-we don't know how the effects are transduced