Chapter 4,5,6 Vocab Flashcards
1
Q
Microelectrodes
A
Extremely fine recording electrodes, which are used for intracellular recording
1
Q
Membrane Potential
A
The difference in electrical charge between the inside and the outside of a cell
1
Q
Resting Potential
A
The steady membrane potential of a neuron at rest, usually about -70 mV
1
Q
Ions
A
Positively or negatively charges particles
1
Q
Random Motion
A
The first of the two homogenizing factors
1
Q
Contrast X-Ray Techniques
A
inject into one compartment of the body a substance that absorbs x-rays either less than or more than the surrounding tissue. The substance then heightens the contrast between the compartment and the surrounding tissue during the X-ray photography.
1
Q
Cerebral Angiography
A
X-ray technique that uses the infusion of a radio-opaque dye into a cerebral artery to visualize the cerebral circulatory system during X-ray photography.
1
Q
Computed Tomography
A
A computer-assisted X-ray procedure that can be used to visualize the brain and the other internal structures of the living body.
1
Q
Magnetic Resonance Imaging
A
Procedure in which high-resolution images are constructed from the measurement of waves that hydrogen atoms emit when they are activated by radio-frequency waves in a magnetic field. Provides clearer images than the CT.
1
Q
Spatial Resolution
A
Ability to detect differences in spatial location
2
Q
Concentration Gradients
A
A concentration gradient occurs where the concentration of something changes over a certain distance
2
Q
Electrostatic Pressure
A
Positively charged ions (cat ions) and negatively charged ions (anions) attract each other but repel their own kind
2
Q
Ion Channels
A
Ions pass through the neural membrane at specialized pores known as the Ion channels, each type of which is specialized for the passage of particular ions
2
Q
Hodgkin and Huxley
A
Neurophysiologists whom provided the first evidence that an energy-consuming process is involved in the maintenance of the resting potential
2
Q
Sodium-Potassium Pump
A
Active transport mechanisms that pump Na+ ions out of neurons and K+ ions in
2
Q
Transporters
A
Mechanisms in the membrane of a cell that actively transport ions or molecules across the membrane
2
Q
Depolarize
A
To decrease the resting membrane potential
2
Q
Hyperpolarize
A
To increase the resting membrane potential
2
Q
Excitatory Postsynaptic Potentials
A
Graded postsynaptic depolarizations, which increase the likelihood that an action potential will be generated
2
Q
Inhibitory Postsynaptic Potentials
A
Graded postsynaptic hyperpolarizations, which decrease the likelihood that an action potential will be generated
2
Q
Graded Responses
A
Responses whose magnitude is indicative of the magnitude of the stimuli that will induce them
2
Q
Axon Hillock
A
The conical structure at the junction between the axon and cell body
2
Q
Positron Emission Tomography
A
Brain-imaging technique that has been widely used in biopsychological research because it provides images of brain activity rather than brain structure.
2
Q
2-deoxyglucose
A
Injected into the patient?s carotid artery. Similar to glucose, so it is quickly taken up by active cells. However, it cannot be metabolized and therefore accumulates. Allowing to see what brain structures are active at certain times.
2
Functional MRI
Produce images of the increase in oxygen flow in the blood to active areas of the brain which allows inferring what brain structure is at work.
2
BOLD Signal
This is the signal that the functional MRI produces. (blood-oxygen-level- dependent signal)
2
Magnetoencephalography
Measures changes in magnetic fields on the surface of the scalp that are produced by changes in underlying patterns of neural activity.
2
Temporal Resolution
An advantage of Magnetoencephalography, the ability to detect differences in time
2
Electroencephalography
A technique for recording the gross electrical activity of the brain, commonly recorded through scalp electrodes
2
Transcranial Magnetic Stimulation
Technique for disrupting the activity in an area of the cortex by creating a magnetic field under a coil positioned next to the skull. Stimulation turns off part of the brain while the effects of the disruption on cognition and behavior are assessed.
2
Alpha Waves
Regular, 8 to 12 second, high amplitude waves that are associated with relaxed wakefulness.
2
Event Related Potentials
Waves that accompany certain psychological events.
2
Sensory Evoked Potential
A type of the event related potentials, the change in the cortical EEG signal that is elicited by the momentary presentation of a sensory stimulation.
2
Signal Averaging
A method used to reduce the noise of the background EEG
3
Threshold of Excitation
The level of depolarization necessary to generate an action potential, usually about -65 mV
3
Average Evoked Potentials
Focuses on the various waves in the averaged signal. When presented a stimulus, the average response time. Plotted then the background EEG is canceled.
4
Action Potential
A massive momentary reversal of a neurons membrane potential from about -70 mV to about +50 mV
4
P300 Wave
This wave occurs only if the stimulus has meaning for the subject. Ex: gets a reward
5
All-or-None Responses
Responses that are not graded, that either occur in their full extent or not at all
5
Far-Field Potentials
The portion of the evoked potential when the stimulus is not influenced by the meaning of the stimulus for the subject.
6
Integration
Adding or combing a number of individual signals into one overall signal
6
Electromyography
Usual procedure for the measuring muscle tension.
7
Spatial Summation
The integration of signals that occur at different sites on the neurons membrane
7
Electrooculography
Electrophysiological technique for recording eye movement
8
Temporal Summation
The integration of neural signals that occur at different times at the same synapse
8
Skin Conductance Level
One of the most common to assess the above. Measure of the background level of skin conductance that is associated with a particular situation
9
Voltage-Activated Ion Channels
Ion channels that open and close in response to changes in the level of the membrane potential
9
Skin Conductance Response
One of the electrodermal activity tests, is a measure of the transient changes in the skin conductance that are associated with discrete experiences.
10
Rising Phase
During the rising phase of an action potential, the membrane potential changes from negative to positive, a depolarization
10
Electrocardiogram
Recording of the heart beat by placing electrodes on the chest. Average is 70/min
11
Re-polarization
Re-polarization refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value
11
Hypertension
A chronic blood pressure of more than 140/90 mmHg.
12
Absolute Refractory Period
A brief period after the initiation of an action potential during which it is impossible to elicit another action potential in the same neuron
12
Sphygmamanometer
Device composed of a hollow cuff, a rubber bulb for inflating, and a pressure gauge. Measures blood pressure.
13
Relative Refractory Period
A period after the absolute refractory period during which a higher-than-normal amount of stimulation is necessary to make a neuron f ire
13
Stereotaxic surgery
Brain surgery using a stereotaxic apparatus to position an electrode or cannula in a specified position of the brain
14
Non-decremental
The conduction of action potentials along an axon
14
Plethysmography
The various techniques for measuring changes in the volume of blood in a particular part of the body
15
Antidromic Conduction
Axonal conduction opposite to the normal direction; conduction from axon terminals back toward the cell body
15
Stereotaxic Atlas
Used to locate brain structure in much the same way a geo atlas. The brain has three dimensions. All distances are measured in millimeters from a designated reference point
16
Orthodromic Conduction
Axonal conduction in the normal direction-from the cell body toward the terminal buttons
16
Bregma
A reference point on the stereotaxic atlas, on top of the skull where two of the major sutures intersect.
17
Nodes of Ranvier
The gaps between adjacent myelin segments on an axon
17
Stereotaxic Instrument
Has two parts: head holder and the electrode holder. Electrode holder allows to be moved in the three dimensions: anterior-posterior, dorsal-ventral, and lateral-medial.
18
Saltatory Conduction
Conduction of an action potential from one node of Ranvier to the next along a myelinated axon
18
Aspiration
The cortical tissue is drawn off by suction through a fine-tipped handleheld glass pipette.
19
Neurodegenerative Diseases
Diseases that damage the nervous system
19
Radio-Frequency Current
Small subcortical lesions are made by this technique when high frequency current is passed through the target tissue from the tip of an electrode.
20
Motor Neurons
Neurons that synapse on skeletal muscles
20
Knife Cuts
Used to eliminate conduction in a nerve or tract. Tiny cut can accomplish this without extensive damage to surrounding tissue.
21
Inter-neurons
Passive and decremental conduction
21
Cryogenic Blockade
When coolant is pumped through an implanted cryoprobe, neurons near the tip are cooled until they stop firing. No structural damage.
22
Hodgkin-Huxley Model
A mathematical model (a type of scientific model) that describes how action potentials in neurons are initiated and propagated. It is a set of nonlinear ordinary differential equations that approximates the electrical characteristics of excitable cells such as neurons and cardiac myocytes.
22
Cryoprobe
Probe in the cryogenic blockade technique
23
Dendritic spines
Tiny nodules of various shapes that are located on the surface of many dendrites and are the sites of most excitatory synapses in the mature mammalian brain
23
Unilateral Lesion
Lesions restricted to one half of the brain
24
Axosomatic Synapses
Synapses of each terminal buttons on somas
24
Bilateral Lesion
Lesions that involving both sides of the brain
25
Dendrodendritic synapses
Types of synapse that is capable of transmission in either direction
25
Bipolar Electrode
Stimulates the brain through two insulated wires wound tightly together and cut at the end.
26
Axoaxonic synapses
Types of synapse that helps mediate presynaptic facilitation and inhabitation
26
Intracellular Unit Recording
Provides a moment-by-moment record of the graded fluctuations in one neuron?s membrane potential
27
Presynaptic Facilitation
Axoaxonic synapses that increase effect on one neuron to another
27
Extracellular Unit Recording
Provides a record of firing of a neuron but no info about the neuron?s membrane potential.
28
Presynaptic Inhibition
Decreases effects of one neuron to another
28
Multiple-Unit Recording
Graph of the total number of recorded action potentials per unit of time
29
Directed Synapses
Synapses at which the site of neurotransmitter release the site of neurotransmitter reception are in close proximity
29
Invasive EEG Recording
EEG signals are recorded through large implanted electrodes rather than through scalp electrodes. Cortical EEG signals are frequently recorded through stainless steel skull screws whereas subcortical EEG signals are typically recorded through stereotaxically implanted wire electrodes.
30
Non directed Synapses
Synapses at which the site of neurotransmitter release and the site of neurotransmitter reception are not close together
30
Intraperitoneally
When drugs are injected hyperodermically into the peritoneal cavity of the abdomen.
31
String-of-Beads Synapses
String like shaped synapses
31
Intramuscularly
When drugs are injected into a large muscle
32
Neuropeptides
Short amino acid chains comprising between 3 and 36 amino acids; in effect they are short proteins
32
Subcutaneously
When drugs are injected fatty tissue beneath the skin
33
Synaptic Vesicles
Small spherical membranes that store neurotransmitter molecules and release them into the synaptic cleft
33
Intravenously
When drugs are injected into large veins
34
Golgi Complex
Structures in the air cell bodies and terminals buttons of neurons that package neurotransmitters and other molecules in vesicles
34
Cannula
A fine, hollow tube that has been stereotaxically implanted in the brain
35
Coexistence
The presence of more than one neurotransmitter in the same neuron
35
Neurotoxins
Neural poisons
36
Exocytosis
The process of releasing a neurotransmitter
36
Autoradiography
When slices of the brain are coated with a photographic emusion, stored in the dark for a few days and then developed much like film. High levels of 2-DG are black spots.
37
Voltage-Activated Calcium Channels
When stimulated by action potentials, these channels open, and Ca2+ ions enter the button
37
Cerebral Dialysis
Method of measuring the extracellular concentration of specific neurochemicals in behaving animals. Animal doesn?t need to be killed in this technique.
38
Receptors
Cells that are specialized to receive chemical, mechanical or radiant signals from the environment; also proteins that contain binding sites for particular neurotransmitters
38
Chromatograph
A device for measuring the chemical constituents of liquids or gases
39
Ligand
A molecule that binds to another molecule; neurotransmitters are ligands of their receptors
39
Antigens
Proteins on the surface cells that identify them as native or foreign
40
Receptor Subtypes
The different types of receptors to which a particular neurotransmitter can bind
40
Immunocytochemistry
Procedure for locating particular neuroproteins in the brain by labeling their antibodies with a dye or radioactive element then exposing the slices to the labeled antibodies.
41
Iontropic Receptors
Receptors that are associated with ligand activated ion channels
41
In Situ Hybridization
Another technique for locating peptides and other proteins in the brain; molecules that bind to the mRNA that directs synthesis of the target protein are synthesized and labeled, and the brain slices are exposed to them.
42
Metabotropic Receptors
Receptors that are associated with signal proteins and G protein
42
Gene Knockout Techniques
Procedures for creating organism that lack a particular gene under investigation
43
G Proteins
Protein that is attached to a protein of signal protein. Once neurotransmitters binds to meta receptors, sub unit of G protein breaks off or trigger synthesis of 2nd messenger
43
Antisense Drugs
Helps to circumvent the problems with gene knockout technique, allows for an organism to develop normally but then reaches into their brain and blocks expression of a particular gene.
44
Second Messenger
A chemical synthesized in a neuron in response to the binding of a neurotransmitter to a metabotropic receptor in its cell membrane
44
Gene Replacement Techniques
Procedures for creating organisms in which a particular gene has been replaced with another
45
Autoreceptors
A type of metabotropic receptor located on the presynaptic membrane and sensitive to a neuron’s own neurotransmitter
45
Green Florescent Protein
A protein composed of 238 amino acid residues that exhibit bright green fluorescence when exposed to light in the blue to ultraviolet range.
46
Reuptake
The drawing back into the terminal button of neurotransmitter molecules after their release into the synapse; the more common of the two mechanisms for deactivating a released neurotransmitter
46
Brainbow
The process by which individual neurons in the brain can be distinguished from neighboring neurons using fluorescent proteins.
47
Enzymatic Degradation
The breakdown of chemicals by enzymes-one of two mechanisms for deactivating released neurotransmitters
47
Transgenic Mice
When mice contain the genetic material of another species
48
Enzymes
Proteins that stimulate or inhibit biochemical reactions without being affected by them
48
Intelligence Quotient
An intelligence quotient, or IQ, is a score derived from one of several standardized tests designed to assess intelligence.
49
Acetylcholine
A neurotransmitter that is created by the addition of an acetyl group to a choline molecule
49
Behavioral Paradigm
Single set of procedures developed for the investigation of a particular behavioral phenomenon
50
Acetylcholinesterase
The enzyme that breaks down the neurotransmitter acetylcholine
50
Single-Test Approach
Goal was to discriminate between patients with psychological problems resulting from structural brain damage and those with psychological problems resulting from functional rather than structural.
51
Gap Junction
Narrow spaces between adjacent neurons that are bridged by fine tubular channels containing cytoplasm through which electrical signals and small molecules can pass readily
51
Standardized-Test-Battery Approach
Goal to id brain-damaged patients but the testing involved standardized sets rather than a single test. Most common of this, Halstead-Reitan
52
Amino Acid Neurotransmitters
A class of small-molecule neurotransmitters, which includes the amino acids glutamate and GABA
52
Customized-Test-Battery Approach
Not just to id patients with brain damage but the objective is to characterize the nature of the psychological deficits of each brain-damaged patient. Use common battery tests then a custom set of tests.
53
Glutamate
The brain’s most prevalent excitatory neurotransmitter, whose excessive release causes much of the brain damage resulting from cerebral ischemia
53
Halstead-Reitan Neuropsychological Test Battery
Most widely used Standarized-test-battery approach. Brain-damaged patients tend to perform poorly on this.
54
Aspartate
An amino acid neurotransmitter that is a constituent of many of the proteins that we eat
54
Wechsler Adult Intelligence Scale
Helps neuropsychologists to infer later on other tests when they know the IQ. Published in 1955
55
Glycine
An amino acid neurotransmitter that is a constituent of many of the proteins that we eat
55
Digit Span
Most widely used test of short memory. Ids the longest sequence of random digits that a patient can repeat correctly 50% of the time. Most ppl have a 7 digit span
56
Gamma-aminobutyric Acid
The amino acid neurotransmitter that is synthesized from glutamate; the most prevalent inhibitory neurotransmitter in the mammalian nervous system
56
Token Test
20 tokens of 2 diff shapes, 2 sizes, and five colors. Examiners says to touch a certain, size, shape and color.
57
Monoamine Neurotransmitters
Small molecule neurotransmitters that are synthesized from monoamines and comprise two classes: catecholamines and indolamines
57
Sodium Amytal Test
Injecting the anethtic sodium amytal into either of the carotoid arteries in the neck. Temp anesthetizes the same-side hemisphere while leaving the other side unaffected. Several language tests are administered while this is happening.
58
Dopamine
One of three catecholamine neurotransmitters; dopaminergic neurons are damaged in Parkinsons disease
58
Dichotic Listening Test
Sequences of spoken digits are presented to subjects through stereo headphones. Three digits are presented to one ear and three diff to the other ear. Then they are asked to repeat as many of the six digits as they can. Report more that are connected to the language center, which was deteremined by the sodium amytal test.
59
Epinephrine
One of the three catecholamine neurotransmitters
59
Contralateral
Projecting from one side of the body to the other
60
Norepinephrine
One of the three catecholamine neurotransmitters
60
Ipsilateral
Situated or appearing on or affecting the same side of the body
61
Serotonin
An indolamine neurotransmitter; the only member of this class of monoamine neurotransmitters found in the mammalian nervous system
61
Short-Term Memory
Holds about seven items for less than 30 seconds without rehearsal; also called the working memory because it is the mental workspace for tasks being thought about at any given moment.
62
Indolamines
The class of monoamine neurotransmitters that are synthesized from tryptophan; serotonin is the only member of this class found in the mammalian nervous system
62
Long-Term Memory
Relatively permament memory system with virtually unlimited capacity.
62
Anterograde Amnesia
Loss of memories for events that occurred after the amnesia
63
Soluble-Gas Neurotransmitters
A class of unconventional neurotransmitters that include nitric oxide and carbon monoxide
63
Retrograde Amnesia
Loss of memories for events that occurred prior to the amnesia
64
Nitric Oxide
A soluble-gas neurotransmitter
64
Semantic Memory
Part of the declarative memory that holds general knowledge
65
Carbon Monoxide
A soluble-gas neurotransmitter
65
Episodic Memory
Part of the declarative memory that contains memories of personally experienced events.
66
Retrograde Transmission
At some synapses, they transmit feedback signals from postsynaptic neuron back to the presynaptic neuron
66
Implicit Memory
Memory with a lack of conscience/awareness in the act of recollection
67
Endocannabinoids
A class of unconventional neurotransmitters that are chemically similar to the active components of marijuana
67
Explicit Memory
Opposite of implicit. Conscious remembering
68
Anandamide
The first endogenous endocannabinoid to be discovered and characterized
68
Repetition Priming Tests
A test that study the pattern that amnesic patients display severe deficits in explicit memory with no deficits at all in implicit memory.
69
Pituitary Peptides
One of the five classes of neuropeptide transmitters; it consists of those first identified as hormones released by the pituitary
69
Wisconsin Card Sorting Test
It is a customized test for people with an injury to the frontal lobe. Sorting cards either by color, number or symbol and the patients with frontal lobe damage sort by the way asked before.
70
Hypothalamic Peptides
One of the five classes of neuropeptide transmitters; it consists of those first identified as hormones released by the hypothalamus
70
Cognitive Neuroscience
Division of biopsychology that focuses on the use of functional brain imaging to study the neural bases of human cognition.
71
Brain-Gut Peptides
One of the five classes of neuropeptide transmitters; consists of those first discovered in the gut
71
Constituent Cognitive Processes
Each complex cognitive process results from the combined activity of simple cognitive processes.
72
Opioid Peptides
One of the five classes of neuropeptide transmitters; it consists of those with a structure similar to the active ingredients of opium
72
Paired-Image Subtraction Technique
The use of PET or fMRI to locate constituent processes in the brain by producing an image of the diff in the brain activity associated with two cognitive tasks that differ in terms of a single constituent process.
73
Miscellaneous Peptides
One of the five classes of neuropeptide transmitters; it consists of those that don’t fit into the other four classes
73
Species-Common Behaviors
Those that are displayed by virtually all members of a species
74
Agonist
Drugs that facilitate the effects of a particular neurotransmitter
74
Open-Field Test
Subject is placed in a large, barren chamber, and its activity is recorded.
75
Receptor Blockers
Antagonistic drugs that bind to postsynaptic receptors without activating them and block the access of the usual neurotransmitter
75
Thigmotaxic
The fact that rats rarely venture away from the walls of the test chamber and rarely engage in such activities as rearing or grooming. (fearful rats become this)
76
Nicotine
The major psychoactive ingredient of tobacco
76
Colony-Intruder Paradigm
Typical patterns of aggression and defensive behavior can be observed and measured during combative encounters between the dominant rat of an established colony and a smaller male intruder.
77
Muscarine
A poisonous substance found in some mushrooms
77
Elevated Plus Maze
Four armed, plus-sign shaped maze that is a test of defensiveness that is commonly used to study in rats anxiolytic (anxiety-reducing) effects of drugs. Two arms have sides and two do not.
78
Atropine
A receptor blocker that exerts an antagonistic effect at muscarinic receptors
78
Lordosis
Posture when a female is sexually receptive
79
Curare
An extract of a certain class of woody vines
79
Intromission
When a male rat inserts his penis
80
Botox
Blocks the release of acetylcholine at neuromuscular junctions and is used cosmetically to treat wrinkles
80
Ejaculates
Ejects his sperm
81
Periaqueductal Gray
The gray matter around the cerebral aqueduct, which contains opiate receptors and activates a descending analgesia circuit
81
Lordosis Quotient
Proportion of mounts that elicit lordosis
82
Endogenous
Naturally occurring in the body
82
Pavlovian Conditioning Paradigm
Experimenter pairs an initially neutral stimulus, conditional stimulus, with an unconditioned stimulus?a stimulus that elicits an unconditional response. As a result of these pairings, the conditioned stimulus can elicit a conditional response
83
Enkephalins
The first class of endogenous opiods to be discovered
83
Operant Conditioning Paradigm
The rate at which a particular voluntary response is emitted is increased by reinforcement or decreased by punishment.
84
Endorphins
A class of endogenous opiods
84
Self-Stimulation Paradigm
Animals press a lever to deliver electrical stimulation to particular sites in their own brains
85
Pleasure Centers
Parts of the brain that support self-stimulation
86
Conditioned Taste Aversion
Avoidance response that develops to tastes of food whose consumption has been followed by illness
87
Neophobia
Afraid of new things
88
Temporal Contiguity
A term that indicates the closeness in time of two or more events. The temporal contiguity of events is important in learning.
89
Principle of Equipotentiality
The view that conditioning proceeds in basically the same manner regardless of the particular stimuli and responses under investigation.
90
Radial Arm Maze
An array of arms, usually eight arms, radiating from a central starting area. At the end of each arm is a food cup, which may or may not be baited(have food), depending on the purpose of the study.
91
Morris Water Maze
Rats are placed in a circular, featureless pool of cool, milky water, in which they must swim until they discover the escape platform. The rats learn to swim directly to the platform by using spatial cues.
92
Conditioned Defensive Burying
When rats receive a single aversive object mounted on the wall and the rats respond by flinging bedding material at it.
93
Nanometers
Billionths of a meter
94
Infrared Waves
Too long for humans to see
95
Wavelength
Plays an important role in the perception of color
96
Intensity
Plays an important role in the perception of brightness
97
Brightness
intensity
98
Sensitivity
The ability to detect the presence of dimly lit objects
99
Acuity
The ability to see the details of objects
100
Retina
Part of the eye where the image falls on (upside down)
101
Pupil
Light enters through here- the hole in the iris
| Iris and the muscles that gives our eye the color
102
Ciliary Muscles
The tension in the ligaments holding each lens in place
103
Accommodation
The process of adjusting the configuration of the lenses to bring images into focus on the retina
104
Converge
Eyes that turn slightly inward; Greatest when you are inspecting things that are close
105
Binocular Disparity
The difference in the position of the same image on two retinas; Can construct 3 dimensional perception
106
Receptors
One of the five layers composing the retina; Specialized to receive chemical, mechanical, or radiant signals from the environment
107
Horizontal Cells
Type of retinal neurons whose specialized function is lateral communication
108
Bipolar Cells
Form the middle layer of the retina
109
Amacrine Cells
Type of retinal neurons whose specialized function is lateral communication
110
Blind Spot
The gap in the receptor layer for the bundle of retinal ganglion cell axons to leave the eye
111
Fovea
Indentation, about .33 centimeters, at the center of the retina
112
Completion
Filling in; The visual system uses information provided by the receptors around the blind spot to fill in the gaps in your retinal image
113
Surface Interpolation
The process by which we perceive surfaces; The visual system extracts information about edges and from it infers the appearance of large surfaces
114
Cones
Visual receptors in the retina that mediate high acuity (ability to see details) color vision in good lighting
115
Rods
Visual receptors in the retina that mediate achromatic, low acuity vision under dim light
116
Duplexity Theory
Theory that cones and rods mediate different kinds of vision
117
Photopic Vision
Gone mediate vision; Predominates in good lighting and provided high-acuity colored perceptions of the world
118
Scotopic Vision
dim illumination—there is not enough light to reliably excite the cones; more sensitive than photopic & lacks detail and color; rod mediated
119
Nasal Hemiretina
The half of each retina next to the nose
120
Temporal Hemiretina
The half next to the temples
121
Spectral Sensitivity Curve
Graph of the relative brightness of lights of the same intensity presented at different wavelength
122
Photopic Spectral Sensitivity Curve
Photopic spectral sensitivity of humans can be determined by having subjects judge the relative brightness of different wavelengths of light shone on the fovea; A light at 500 nm would have to be much more intense that one at 560 nm to be equally bright
123
Scotopic Spectral Sensitivity Curve
Can be determined by asking subjects to judge the relative brightness of different wavelengths of light shone on the periphery of the retina at an intensity too low to activate the few peripheral cones that are located there
124
Purkinje Effect
In intense light, red and yellow wavelengths look brighter than blue or green wavelengths of equal intensity; in dim light, blue and green wavelengths look brighter than red and yellow wavelengths of equal intensity
125
Fixational Eye Movements
Our eyes continuously moving
126
Saccades
Small jerky movements or flicks of the eye
127
Transduction
Conversion of one form of energy to the other visual transduction is the conversion of light to neural signals by the visual receptors
128
Pigment
Any substance that absorbs light
129
Rhodopsin
The photopigment of rods; Absorbs light and bleaches when exposed to intense light; G-Protein that responds to light
130
Bleaching
Lose its color
131
Absorption Spectrum
A graph of the ability of a substance to absorb light of different wavelengths
132
Retina
Geniculate-Striate Pathways - Conduct signals from each retina to the primary visual cortex via the lateral geniculate nuclei
133
Primary Visual Cortex
Striate cortex
134
Lateral Geniculate Nuclei
The six-layered thalamic structures that receive input from the retinas and transmit their output to the primary visual cortex
135
Retintopic
Each level of the retina-geniculate-striate system is organized like a map of the retina
136
Parvocellular Layers
Layers composed of neurons with small cell bodies- run through the top four layers through each lateral geniculate nucleus
137
Magnocellular Layers
Composed of neurons with large cell bodies—bottom two layers of lateral geniculate nucleus
138
Mach Bands
Nonexistent stripes of brightness and darkness running adjacent to the edges –they enhance the contrast at each edge and make it easier to see
139
Contrast Enhancement
Every edge we look at is highlighted for us by contrast-enhancing mechanisms of our nervous system; Intensification of the perception of edges
140
Lateral Inhibition
When a receptor fires, it inhibits its neighbors via the lateral neural network it spreads laterally across the array of receptors
141
Receptive Field
The area of the visual field within which it is possible for a visual stimulus to influence the firing of that neuron
142
Monocular
Each neuron had a receptive filed in one eye, but not the other
143
On-Center Cells
Respond to lights shone in the central region of their receptive fields with “on” firing and to lights shone in the periphery of their receptive fields with inhibition, followed by “off” firing when the light is turned off
144
Off-Center Cells
They respond with inhibition and “off” firing in response to lights in the center of their receptive fields and with “on” firing to lights in the periphery of their receptive fields
145
Simple Cells
```
Receptive fields (on and off regions) unresponsive to diffuse light; monocular; are straight lines rather than circles
Respond best to bars of light in a dark field, dark bars in a light field, or single straight edges between dark and light areas; Each simple cell preferred straight-edge stimulus is in a particular position and in a particular orientation
```
146
Complex Cells
More numerous than simple cells; Rectangular receptive fields and respond best to straight-line stimuli; Larger receptive fields; Not possible to divide the fields of complex cells into static on or off regions
147
Binocular
Responds to stimulation of either eye
148
Ocular Dominance
Respond more robustly to stimulation of one eye than they do to the same stimulation of the other (monkeys)
149
Retinal Disparity
Some binocular cells fire best when the preferred stimulus is presented to both eyes at the same time, but in slightly different positions on the two retinas; Depth perception
150
Component Theory (trichromatic)
There are three different kinds of color receptors, each with a different spectral sensitivity; Mixing together three different wavelengths of light in different proportions (for visual color); The color of any one of them cannot be matched by a mixing of the other two
151
Opponent Process Theory
Ewald Hering in 1878; Two different classes of cells in the visual system for encoding color and another class for encoding brightness; Each of the three classes of cells encoded two complementary colors of perception
152
Complementary Colors
Pairs of colors that produce white or gray when combined in equal measure (green light and red light)
153
Catecholamines
The three neurotransmitter that are synthesized from the amino acid tryrosine dopamine, epinerphrine, and norepinephrine
154
Trichromats
Possessing three color vision photo pigments
Color Constancy - the fact that the perceived color of an object is not a simple function of the wavelengths reflected by it ; wavelengths by colored shirt changed, color of shirt did not
155
Retinex Theory
the color of an object is determined by its reflectance (proportion of light of different wavelength that a surface reflects)
156
Dual-Opponent Color Cells
Monkey visual cortex ; Responds with vigorous on firing when the center of their circular receptive field is illuminated with one wavelength (such as green) and the surround is simultaneously illuminated with another wavelength (red)
157
Cytochrome Oxidase
Mitochondrial enzyme- their distribution in the primary visual cortex can be visualized if one stains slices of tissue with stains that have an affinity for this enzyme
158
Blobs
Peglike, cytochrome oxidase-rich, dual-opponent color columns
159
Secondary Visual Cortex
Those that receive most of their input from the primary visual cortex
160
Visual Association Cortex
Those that receive input from areas of secondary visual cortex as well as from the secondary areas of other sensory systems
161
Prestriate Cortex
Band of tissue in the occipital lobe that surrounds the primary visual cortex
162
Inferotemporal Cortex
Cortex of the inferior temporal lobe
163
Posterior Parietal Cortex
Areas of association cortex that receive visual input that is located in several parts of the cerebral cortex
164
Scotoma
An area of blindness that occurs from damage to an area of the primary visual cortex
165
Perimetry Test
Patient’s head is held motionless on a chin rest, the patient stares with one eye at a fixation point on the screen—press a button when the dot is seen
166
Hemianopsic
'
Having a scotoma covering half of the visual field; May see an entire face when they focus on the persons nose, even when the side of the face in the scotoma has been covered by a blank card
167
Conscious Awareness
you assume that if a person sees something, he or she will be consciously aware of seeing it
168
Blindsight
Ability of such patients to respond to visual stimuli in their scotomas even though they have no conscious awareness of the stimuli
169
Dorsal Stream
Flows from the primary visual cortex to the dorsal prestriate cortex to the posterior parietal cortex; Responds to spatial stimuli—location of objects and their direction of movement'
170
Ventral Stream
Flows from the primary visual cortex to the ventral prestriate cortex to the inferotemporal cortex; Responds to the characteristics of objects—color and shape, for example
171
“Where” vs. “What” Theory
damage to some areas of the cortex may abolish certain aspects of vision while leaving others unaffected—come from the comparison of the specific effects of damage to the dorsal and ventral streams; dorsal stream is involved in the “where” and ventral is involved in the “what”
172
"Control of Behavior” versus “Conscious
Perception” Theory - the function of the dorsal stream is to direct behavioral interactions with objects, whereas the function of the ventral stream is to mediate the conscious perception of the objects
173
Prosopagnosia
Visual agnosia for faces
174
Agnosia
Failure of recognition that is not attributable to a sensory deficit or to verbal or intellectual impairment
175
Visual Agnosia
A specific agnosia for visual stimuli; Can see visual stimuli, but do not know what they are
176
Movement Agnosia
Difficulties in recognizing movement
177
Object Agnosia
Difficulties in recognizing objects
178
Color Agnosia
Difficulties in recognizing colors
Fusiform Face Area - Damage to the ventral stream in the area of the boundary between the occipital and temporal lobes; Parts of this area are selectively activated by human faces
179
Akinetopsia
Deficiency in the ability to see movement progress in a normal smooth fashion
Triggered by high doses of certain antidepressants
