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Behavioral Neuroscience
Exam 2
308
Psychology
Undergraduate 3
02/17/2012

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Term
Does heredity influence facial expressions?
Definition
Yes, people that are born blind and ,therefore could not of learned facial expressions from imitation, facial expressions were remarkably similar to those of their sighted relatives.
Term
Genes
Definition
Units of heredity that maintain their structural identity from one generation to another
Term
Where are the pairs of genes aligned on?
Definition
Chromosomes
Term
Chromosomes
Definition
strands of genes which come in pairs(w/ the exception of male mammals who have an unpaired X and Y chromosome with different genes
Term
DNA
Definition
-a portion of the chromosome
-double stranded
-DNA = Deoxyribonucleic acid
Term
What does DNA serve as a template for?
Definition
Ribonuleic Acid
Term
RNA
Definition
-Ribonuleic Acid
-RNA is a single strand chemical
Term
Enzymes
Definition
Biological catalysts that regulates chemical reactions in the body
Term
Homozygous
Definition
Anyone with an identical pair of genes on the two chromosomes
-usually related only for a particular gene
Term
Heterozygous
Definition
An individual with an unmatched pair of genes
-for a particular gene
Term
Dominant Gene
Definition
shows a strong effect in either the homozygous or heterozygous condition
Term
Recessive Gene
Definition
Gene shows its effect only in the homozygous condition (gene traits only exist in a heterozygous pair)
Term
Suppose you have high sensitivity to tasting PTC(phenylthiocarbamide). If your mother can also taste it easily, what (if anything) can you predict about your father's ability to taste it?
Definition
If your mother has high sensitivity to the taste of PTC, we can make no predictions about your father. You may have inherited a high-sensitivity from your mother, and because the gene is dominant, you need only one copy of the gene to taste PTC.
Term
Suppose you have high sensitivity to the taste of PTC. If your mother has low sensitivity, what (if anything) can you predict about your father?
Definition
If your mother has low sensitivity, you must have inherited your high sensitivity gen from your father, so he must have high sensitivity.
Term
Sex-Linked Genes
Definition
Genes located on the sex chromosomes
Term
Autosomal Genes
Definition
All other chromosomes that are not sex chromosomes are called autosomal chromosomes and their genes are called autosomal genes
Term
Sex-Limited Genes
Definition
Present in both sexes, generally on autosomal chromosomes, but active mainly in one sex(EX. Chest hair in men, breast size in woman)
-Both sexes have these genes but sex hormones activate them primarily in one sex or the other
Term
How does a sex-linked gene differ from a sex-limited gene?
Definition
A sex-linked gene is on a sex chromosome (usually the x chromosome). A sex-limited gene could be on any chromosome, but is activated by sex hormones and therefore shows its effect only in one sex or the other
Term
Monozygotic
Definition
from one egg
Term
dizygotic
Definition
from two eggs
Term
heritability
Definition
If the variation in some characteristics depend largely on genetic differences
Term
Multiple Effect
Definition
If genetic or prenatal influences produce even a small increase in some activity, the early tendency will change the environment in a way that magnifies that tendency with a change of effects.
Term
Adopted children whose biological parents were alcoholics have an increased probability of becoming alcoholics themselves. One possible explanation is heredity. What is another?
Definition
If the mother drank much alcohol during pregnancy the prenatal environment may have predisposed the child to later alcoholism.
Term
PKU
Definition
Phenylketonuria is a genetic inabillity to metabolize the amino acid phenylalanine.
Term
What are the effects of not treating PKU?
Definition
Phenylalanine accumulates to toxic levels, impairing brain development and leaving children mentally retarded, restless, and irritable
Term
Can we modify heritable traits?
Definition
Yes, our abillity to prevent PKU provides particularly strong evidence that heritable does not mean unmodifiable.
Term
What example illustrates the point that even if some characteristic is highly heritable, a change in the environment can alter it?
Definition
Keeping a child with the PKU gene on a strict low-phenylalanine diet prevents the mental retardation that the gene ordinarily causes. The general point is that sometimes a highly heritable condition can be modified environmentally.
Term
Evolution
Definition
is a change over generations in the frequencies of various genes in a population
Term
Artificial Selection
Definition
Choosing individuals with a desired trait and make them the parents of the next generation
Term
Lamarckian Evolution
Definition
evolution through the inheritance of acquired characteristics(no evidence that this occurs)
Term
Many people believe the human appendix is useless. Will it become smaller and smaller with each generation?
Definition
No. Failure to use or need a structure does not make it become smaller in the next generation. The appendix will shrink only if people with a gene for a smaller appendix reproduce more successfully than other people do.
Term
Evolutionary Psychology
Definition
deals with how behaviors have evolved, specifically social behaviors
Term
Altruistic Behavior
Definition
an action that benefits someone other than the actor
Term
Group Selection
Definition
According to this idea, altruistic groups survive better than less cooperative one
Term
Reciprocal Altruism
Definition
the idea that individuals help those who will return the favor
Term
Kin Selection
Definition
Selection for a gene that benefits the individual's relatives
Term
What are two plausible ways for possible altruistic genes to spread in a population?
Definition
Altruistic genes could spread becuase they facilitate care for one's kin or because they facilitat exchanges of favors with others (reciprocal altruism). Group selection may also work under some circumstances, especially if the cooperative group has some way to punish or expel an uncoorperative individual
Term
Fitness
Definition
the number of copies of one's genes that endure in latter generations
Term
Electrical Gradient
Definition
a difference in electrical charge between the inside and outside of the cell
Term
What maintains an electrical gradient in a neuron?
Definition
Membrane
Term
What does the fatty acid inner and outer layer of the membrane provide the it with?
Definition
This structure provides it with a good combination of flexibility and firmness and retards the flow of chemicals between the inside and the outside of the cell
Term
Polarization
Definition
a difference in electrical charge between two locations.
Term
Resting Potential
Definition
The difference in voltage in a resting neuron is called the resting potential. The resting potential is mainly the result of a negatively charged proteins inside the cell.
Term
How can researchers measure a cells resting potential?
Definition
They can measure by sticking an microelectrode into the cell body
Term
How many millivolts is a typical neuron interior?
Definition
-70 millivolts or mV
Term
Selectively Permeable
Definition
Some chemicals can pass through it more freely than others can. (Similar process of the blood brain barrier.)
Term
What ions normally can not go through the selectively permeable membrane? And what can cross freely through always open channels?
Definition
Most large or electrically charged ions and molecules cannot cross the membrane at all. Oxygen, carbon dioxide, urea, and water cross freely though channels that are always open.
Term
What ions pass through voltage gated channels and gated channels?
Definition
Sodium, potassium, calcium, and chloride, cross through the membrane gated channels. These channels are sometimes open and sometimes closed.
Term
When the membrane is at rest, what position is the sodium voltage gated channels in?
Definition
closed
Term
When the cell is at rest, what position is the voltage gated potassium channels in?
Definition
Potassium voltage gated channels are nearly closed, but not entirely closed, so potassium can flow somewhat freely.
Term
Sodium Potassium Pump
Definition
A protein complex, repeatedly transports three sodium ions out of the cell while drawing two potassium ions into it.
Term
Where are the highest concentrations of potassium and sodium?
Definition
Sodium ions are more than 10 times more concentrated outside the membrane than inside, and potassium ions are similarly more concentrated inside than outside?
Term
Name two ways potassium leaves a cell and two ways in enters?
Definition
Potassium can leave the cell because of a high concentration gradient forcing potassium out of the cell, or it can leave and enter through the sodium-potassium pump. Potassium can also enter through electrical gradient.
Term
Electrical Gradient in relations to Sodium
Definition
Sodium is positively charged and the inside of the cell is negatvely charged. Opposite electrical charges attract, so the electrical gradient tends to pull sodium into the cell
Term
Concentration Gradient in relations to sodium
Definition
the difference in distribution of ions across the membrane. Sodium is more concentrated outside than inside, so just by the law of probability, sodium is more likely to enter the cell than leave it.
Term
When the membrane is at rest, are the sodium ions more concentrated inside the cell or outside? Where are the potassium ions more concentrated?
Definition
Sodium ions are more concentrated outside the cell; potassium is more concentrated on the inside.
Term
When The membrane is at rest, what tends to drive the potassium ions out of the cell? What tends to draw them back in again?
Definition
When the membrane is at rest, the concentration gradient tends to drive potassium ions out of the cell; the electrical gradient draws them into the cell. The sodium potassium pump also draws them into the cell.
Term
The body invest a lot of energy to operate the sodium-potassium pump, which maintains resting potential. Why is it worth so much energy?
Definition
Because the resting potential prepares the neuron to respond rapidly
Term
Where does stimulation of a neuron ordinarily take place?
Definition
The synapses
Term
Hyperpolarization
Definition
increasing the negative charge inside a neuron, or increased polarization
Term
Depolarize
Definition
reduce the polarization toward zero
Term
Threshold of Excitation
Definition
When there is a depolarization that is strong enough to cause an action potential in a neuron.
Term
What happens when potential reaches the threshold?
Definition
The membrane suddenly opens its voltage gated sodium channels and permits a rapid flow of ions across the membrane.
Term
Subthreshold Stimulus
Definition
any stimulation that produces a small response proportional to the amount of current
Term
Action Potential
Definition
A rapid depolarization and slight reversal of the usual polarization
Term
What is the difference between hyperpolarization and depolarization?
Definition
A hperpolarization is an exaggeration of the usual negative charge within a cell(to a more negative level than usual). A depolarization is a decrease in the amount of negative charge within the cell.
Term
What is the relationship between the threshold and an action potential?
Definition
A depolarization that passes the threshold produces an action potential. One that falls short of the threshold does not produce an action potential.
Term
Voltage gated channels
Definition
membrane channels whose permeadbility depends on the voltage difference across the membrane. At the resting potential, the channels are closed. As the membrane becomes depolarized, the sodium channels begin to open and sodium flows freely. If the depolarization is less than the threshold, sodium cross the membrane only slightly more than normal.
Term
At the peak of an action potential where are sodium ions more concentrated?
Definition
Fewer than 1% of the sodium ions cross the membrane during an action potential, meaning that sodium is still more concentrated on the outside of a cell.
Term
What happens to the voltage gated sodium channels at the peak of an action potential?
Definition
At the peak of an action potential the sodium gates quickly close and resist reopening for about the next millisecond.
Term
After the peak of the action potential, what brings the membrane back to its original state of polarization?
Definition
The sodium-potassium pump is to slow so the cell opens up voltage gated potassium channels and the voltage gated chloride channels open
Term
What do local anesthetic drugs such as novocain, xylocain do?
Definition
They attach to the sodium channels of the membrane, preventing sodium ions from entering. There by preventing an action potential.
Term
During the rise of the action potential, do sodium ions move into the cell or out of it? Why?
Definition
During the action potential, sodium ions move into the cell. The voltage-dependent sodium gates have opened, so sodium can move freely. Sodium is attracted to the inside of the cell by both and electrical and a concentration gradient.
Term
As the membrane reaches the peal pf the action potential, what ionic movement brings the potential down to the original resting potential?
Definition
After the peak of the action potential, potassium ions exit the cell, driving the membrane back to the resting potential. ( the sodium-potassium pump is not the answer here; it is too slow.)
Term
The all-or-none law
Definition
The amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it.
Term
Where are the amplitude, velocity, and shape of an action potential consistent?
Definition
The amplitude, velocity, and shape are consistent over time for a given axon, but they vary from neuron to neuron.
Term
Refractory Period
Definition
Immediately after an action potential, the cell enters a refractory period during which it resists the production of further action potentials.
Term
Absolute refractory period
Definition
The first part of the refractory period in which the membrane cannot produce an action potential regardless of the stimulation.
Term
Relative refractory period
Definition
During the second part of the refractory period in which a stronger than usual stimulus is necessary to initiate an action potential.
Term
What are the two mechanisms behind the refractory period?
Definition
The voltage gated sodium channels are closed, and the potassium is flowing out of the cell at a faster than usual rate.
Term
State the all-or-none law.
Definition
According to the all-or-none law, the size and shape of the action potential are independent of the intensity of the stimulus that initiated it. That is, every depolarization beyond the threshold of excitation produces an action potential of about the same amplitude and velocity for a given axon.
Term
Does the all-or-none law apply to dendrites? Why or Why not?
Definition
The all-or-none law does not apply to dendrites because they do not have action potentials.
Term
Suppose researchers find that axon A can produce up to 1000 action potentials per second(at least briefly, with maximum stimulation), but axon B can never produce more than 100 per second (regardless of the strength of the stimulus). What could we conclude about the refractory periods of the two axons?
Definition
Axon A must have a shorter absolute refractory period, about 1ms, whereas axon B has a longer absolute refractory period of about 10ms.
Term
Where does an action potential begin on a motor neuron?
Definition
Axon Hillock
Term
Axon Hillock
Definition
A swelling where the axon exits the soma
Term
Where do neural tubes develop from?
Definition
central ectoderm
Term
What happens at two weeks in brain development?
Definition
CNS begins to develop
Term
What happens at seven weeks in brain development?
Definition
The hindbrain, midbrain, forebrain distinguish
Term
What happens at the third trimester in brain development?
Definition
(6-7months) the cortex layering beings formation
Term
What happens at birth in brain development?
Definition
Brain weighs 350g and still is developing
Term
What happens at 9 months postnatal in brain development?
Definition
The frontal cortex development allows "object permanence"
Term
What happens at the end of the first year in brain development?
Definition
Brain weighs 1000g, close to adult weight(1200-1400g)
Term
Proliferation
Definition
new neurons divide from “stem cells” typically situated in central regions
(The production of new cells)
Term
Migration
Definition
neurons crawl and extend filopodia of neurites (axon precursors) seeking new connections
(After cells have differentiated as neurons or glia, the migrate/move. Some neurons migrate much faster than others and a few of the slowest don't reach their final destination until adulthood.)
Term
Differentiation
Definition
(PSGE) soma branches to form dendrites while axon extends… distinctive shapes
Term
Myelination
Definition
myelinating glia wrap around extending axons
-Process by which glia produce the insulating fatty sheaths that accelerate transmission in many vertebrate axons
Term
Synaptogenesis
Definition
synaptic connections are formed with target regions
-Although this process begins before birth, it continues throughout life, as neurons form new synapses and discard old ones.
Term
What are the 5 stages of neuron development?
Definition
1)Proliferation
2)Migration
3)Differentiation
4)Myelination
5)Synaptogenesis
Term
How often are olfactory receptor cells replaced in mammals?
Definition
approximately every 90 days
Term
How do olfactory receptors get replaced?
Definition
Stem Cells at the sub-ventricular zone and around the olfactory area reproduce and migrate
Term
Chemo attractants
Definition
Chemical gradients that growing neurites grow toward
Term
Chemo repellants
Definition
Chemical gradients that growing neurites avoid
Term
Neurotrophins
Definition
Chemicals that promote the survival and activity of neurons
Term
Neurotrophic Factors
Definition
chemicals that increase metabolism, excitability, and efficiency
Term
Nerve Growth Factors
Definition
chemicals that ensure the survival of neurons (some competition for these factors)
Term
Sperry Experiment
Definition
They reversed a newts eyes to see where the axons from the eyes would go to.Connections in the newt grew back to their original target homes
Rather than targets representing the world area perceived from the new retinal location
Therefore it was likely chemical gradients were involved in routing
Term
Retinal ganglion cells originating at the dorsal region of the retina proceed to the ________ portion of the newt tectum.
Definition
ventral
Term
What is a “sex-limited gene?” Do both sexes have these genes and express them?
Definition
This is a gene that both males and females carry, but is only activated into expression in one sex, typically by hormones.
Term
The work of Rita Levi-Montalcini indicated that nerve growth factor prevented apoptosis in certain neuron populations. What is apoptosis?
Definition
Apoptosis refers to “programmed cell death” and essentially means a neuron will activate a series of genetic responses that eventually lead to its demise in the absence of certain external stimuli.
Term
What is the series of mostly “ess” containing words that describe how development leads to cell types? (4 word phrase: ____ ____ of ____ _____).
Definition
Progressive Suppression of Genetic Expression
Term
What happens when blind individuals have their occipital cortex inactivated by transcranial magnetic stimulation that differs from when the same area is inactivated in sighted people?
Definition
This action will interfere with their ability to read Braille and perform other tactile discriminations, something that does not occur when the same region is inactivated in sighted people.
Term
Neuron states available
Definition
relaxed-polarized, (at rest)
agitated-depolarized, (excited)
firing impulse or action potential (spouting off)
Term
Electrostatic force
Definition
Like charges repel, unlike charges attract
Term
voltage (potential)
Definition
Pressure that pushes = voltage (potential)
Term
Diffusion force
Definition
Chemicals free to wander fill a space evenly
Term
TTX (tetrodotoxin)
Definition
blocks selectively the voltage-gated Na+ conductance by physically blocking
Na+ channels.
Term
TEA (tetraethylammonium)
Definition
blocks K+ channels
Term
Absolute refractory period dictates neurons -----?
Definition
Firing rate
Term
The __________ is a necessary part of v-gated sodium channels to force propagation in one direction.
Definition
inactivation gate
Term
Where are most of the sodium ions located when a neuron is “at rest” and not firing action potentials and where do gradients push them?
Definition
Most of the sodium ions are located outside the membrane and gradients are pushing them towards the inside of the membrane while neurons are at rest.
Term
The time following one action potential before another action potential can occur is called the ___________.
Definition
refractory period
Term
How do local anesthetic drugs such as Novocaine and Xylocaine prevent pain messages from reaching the brain?
Definition
These substances block the sodium channels involved in action potentials and so prevent the local sensory neurons from carrying pain information towards the central nervous system or the brain.
Term
Subthreshold depolarizations are graded while action potentials are _______________.
Definition
all-or-nothing
Term
Neuron electrical impulses are driven by
Definition
concentration and charge gradients (primarily sodium and potassium), and special voltage-dependant channels
Term
Benefits of Saltatory Conduction
Definition
Less Na+ to pump back out
Less Na+/K+ pumps to express
Less voltage-dependant Na+ or K+ ion channels to express
Only at node of Ranvier
Dramatically increased speed
Squid giant axon 500μm, unmyelinated speed of 35 m/sec
Fastest myelinated axon 20μm, speed of 120 m/sec
Term
What does the opening of voltage dependent sodium channels propagate?
Definition
Action Potential Moving down the axon
Term
What does opening of the voltage dependent calcium channels initiate?
Definition
docking and release of neurotransmitter from vesicles
Term
What aspect of a fiber-optic cable acts in a manner analogous to the myelin surrounding neuron axons?
Definition
The reflective coating surrounding the inner core acts analogously to the myelin sheath as it reflects light back into the core while the myelin sheath reflects charged current into the “cable” or cytoplasm making it travel farther in the cable rather activating voltage-gated channels.
Term
For an action potential to transmit, what is the limiting factor regarding the distance between the nodes of Ranvier?
Definition
The distance between nodes of Ranvier must not be so far apart that the strength of a voltage change dissipates by resistance before reaching the next node. If too much dissipation occurs, the voltage change at the next node will be insufficient to activate the voltage-gated channels and perpetuate the signal.
Term
What happens to a rat immunized with myelin basic protein (what cell types are attacked and what happens to behavior)?
Definition
Its myelin sheath-producing cells (mostly Schwann cells but perhaps some oligodendrocytes) will be attacked and as these are destroyed the animal will become paralyzed.
Term
The small bubbles of membrane found within the axon terminal are called ________.
Definition
synaptic vesicles
Term
What is wrong with the “shiverer” mouse?
Definition
A shiverer mouse has disruptions in the gene that produces myelin basic protein such that this protein is incapable of performing its role within the myelin sheath properly so mice have a shake to their movements due to improperly timed action potentials to their muscles.
Term
EPSP: Excitatory Post Synaptic potential
Definition
Neurotransmitter causes local, graded depolarization on the postsynaptic neuron
Term
IPSP: Inhibitory Post Synaptic Potential
Definition
Neurotransmitter causes local, graded hyperpolarization on the postsynaptic neuron
Term
Quanta
Definition
the amount of neurotransmitter stored in a single synaptic vesicle, thus the lowest level potential postsynaptic effect
Term
Differences between neurochemicals
Definition
They are produced from different raw materials at different places in the neuron
Some work quickly to depolarize or hyperpolarize, others work more slowly
Some directly open ion channels
Some initiate an intracellular cascade of events
Their effects on the “postsynaptic” membrane are stopped in different ways
Direct metabolism by enzymes after release
Reuptake transport by ATP-driven pumps
Some are capable of diffusing more than others
Term
Neurotransmitters
Definition
Amino acids, which contain an amine group
Peptides: long chains of amino acids, including polypeptides and proteins
Acetylcholine: made from choline, essential nutrient in diet
Monoamines: non-acidic neurotransmitters containing an amine group
Purines: category of chemical including adenosine and several of its derivatives
Gases: nitric oxide and maybe others
Term
Hormones
Definition
Released into bloodstream
More global body control
Multiple sites of action
Often nuclear actions
Term
Neuropeptides
Definition
Released from neurons to general extracellular space
Not restricted to axonal release
Typically after higher activity
Term
Agonist:
Definition
a drug that mimics or increases the effects of a neurotransmitter
Term
Antagonist:
Definition
a drug that blocks or takes away from the effects of the neurotransmitter
Term
Affinity:
Definition
ability of a drug to bind a receptor
Term
Efficacy:
Definition
the degree to which the drug activates the receptor once bound
Term
Two types of “summation” were discussed. One requires multiple axon terminals from different sources to converge on a single neuron while the other can function with a single synapse. Distinguish between these two types of summation using approximately a sentence for each.
Definition
Temporal summation requires that depolarizing input arise from a single source but rapidly enough that the influence of one synaptic activation will be lingering when the subsequent activations arise, and they build up to threshold. Spatial summation requires that several different terminals arising from different sources arrive at the same neuron, converging their activating inputs relatively simultaneously such that their combined depolarizing influences merge and cause the neuron membrane to reach threshold.
Term
Where are the taste buds located on the tongue?
Definition
On the tip, sides, and back of tongue
Term
What type of receptors the the center of the tongue have?
Definition
The center of the tongue has somatosensory(texture) receptors
Term
How often are the taste buds replaced?
Definition
10-14days
Term
Types of taste
Definition
Sweet (sugar, fruit ripe?)
Salty (sodium, we seek salt for fluid balance)
Sour (acidic, many spoiled foods)
Bitter (alkaloids in plants often poisonous)
Amino Acids, umami (glutamate, aspartate)
Term
What is the difference between taste and flavor?
Definition
We can only taste 5 different things where flavor is a combination of taste and smell.
Term
Bioavailability
Definition
Fraction of drug that reaches the target destination of action (if reachable through bloodstream, then plasma content)
Term
Agonist:
Definition
Drug that binds to a receptor and causes a similar effect as the neurotransmitter
Term
Direct agonist:
Definition
competes with transmitter for same binding site
Term
Indirect agonist
Definition
binds to a different site on receptor and due to conformational change influences transmitter effect
Term
Antagonist:
Definition
Drug that binds to a receptor and blocks the action of neurotransmitters or other drugs (agonists)
Term
Direct antagonist:
Definition
binds to receptor at the same site as the transmitter but has no inherent effect when bound
Term
Indirect antagonist:
Definition
binds noncompetitively and causes a conformational change or receptor destruction resulting in blocked signal
Term
Partial agonist
Definition
binds to receptor but only causes a transmitter-like effect partially
Term
Inverse agonist:
Definition
drug that binds noncompetitively and reverses the effectiveness of the transmitter
Term
Where are cannabinoid receptors typically located, on what aspect of neurons?
Definition
These are typically located on the presynaptic area, (or on axon terminals).
Term
What happened when Di Lorenzo and colleagues stimulated the rat taste-sensitive region of the medulla in a pattern similar to that recorded when they tasted quinine while they drank water?
Definition
These rats acted like the water tasted bad and began to avoid drinking it.
Term
Both rats and people that administer heroin regularly will likely experience _________ symptoms when heroin is taken away
Definition
withdrawal
Term
The ________ taste is likely helpful in maintaining a healthy fluid balance.
Definition
salty
Term
What capacity does the olfactory system have in terms of its neurons that is not common in the rest of the CNS?
Definition
The olfactory neurons are regularly replaced/replenished over time with new neurons throughout our lifetime.
Term
The grater the diameter of the axon the ________the ions flow. (Because of _______resistance)
Definition
Faster
decreased
Term
Propagation of the action potential
Definition
describes the transmission of an action potential down an axon. Action potential gives birth to an new action potential at each node of ranvier along the axon.
Term
Sheaths of Myelin
Definition
an insulating material composed of fats and proteins
Term
Myelinated Axons
Definition
those covered with a myelin sheath. Meylinated axons are found only in vertebrates, and are covered with fats and proteins.
Term
Nodes of Ranvier
Definition
Interruptions in the Myelin sheath where a short section of the axon is located.
Term
Salatory Conduction
Definition
The jumping of action potential from node to node.
In addition to providing rapid conduction of impulses, salatory conduction conserves energy
Term
Multiple Sclerosis
Definition
Is one of several demyelinating diseases in which the immune system attacks meylin sheath.
Term
M.S. symptoms
Definition
People with multiple sclerosis suffer a variety of impairments, ranging from visual impairments to poor muscle control.
Term
In a mylinated axon, how would the action potential be affected if the nodes were much closer together? How might it be affected if the nodes were much farther apart?
Definition
If the nodes were closer, the action potential would travel more slowly. If they were much farther apart, the current might not be able to diffuse from one node to the next and still remain above the threshold, so the action potential might stop.
Term
Local Neurons
Definition
Neurons without axons that exchange information only with their closest neighbors.
Term
What type of potential due local neurons create?
Definition
Graded potentials
Term
Graded potential
Definition
membrane potential that varies in magnitude without following the all-or-none law.
Term
How can astrocytes be considered local neurons?
Definition
Although they are glia cells, the have no action potentials, but they rapidly exchange chemicals back and forth with neighboring cells
Term
What do we mean when we say that the brain anatomy is plastic?
Definition
It is constantly changing, within limits.
Term
Which develops first, a neuron's axon or its dendrites?
Definition
The axon forms first
Term
In which brain areas do new neurons form in adults?
Definition
Olfactory receptors, neurons in the hippocampus, and neurons in the song-producing areas of some bird species
Term
What evidence indicated that new neurons seldom or never form in the adult cerebral cortext?
Definition
The (14)C concentration in the DNA of cerebral cortex neurons corresponds to the level during the year the person was born, indicating that all or nearly all of those neurons are as old as the person.
Term
What was Sperry's evidence that axons grow to a specific target instead of attaching at random?
Definition
Sperry found that if he cut a newt's eye and inverted it, axons grew back to their original targets, even though they were inappropriate to their new position on the eye.
Term
If all cells in an amphibians's tectum produced the same amount of TOP(dv), what would be the effect on the attachment of axons?
Definition
Axons would attach haphazardly instead of arranging themselves according to their dorsoventral position on the retina.
Term
If axons from the retina were prevented from showing spontaneous activity during early development, what would be the probable effect on development of the lateral geniculate?
Definition
The axons would attach based on chemical gradient but could not fine-tune their adjustment based on experience. Therefore, the connections would be less precise.
Term
What process assures that the spinal cord has the right number of axons to innervate all the muscle cells?
Definition
The nervous system builds far more neurons than it needs and discards through apoptosis those that do not make lasting synapses
Term
What class of chemicals prevents apoptosis?
Definition
Neurotrophins, such as nerve growth factor
Term
At what age does a person have the greatest number of neurons: Before birth, during childhood, during adolescence, or during adulthood.
Definition
The neuron number is greatest before birth.
Term
Anesthetic drugs increase inhibition of neurons, blocking most action potentials. Why would we predict that exposure to anesthetics might be dangerous to the brain of a fetus?
Definition
Prolonged exposure to anesthetics might produce effects similar to fetal alcohol syndrome. Fetal alcohol syndrome occurs because alcohol increases inhibition and therefore increases apoptosis of developing neurons
Term
In the ferret study, how did the experimenters determine that visual input to the auditory portions of the brain actually produced a visual sensation?
Definition
They trained the ferrets to respond to stimuli on the normal side, turning one direction in response to sounds and the other direction to lights. Then they presented light to the rewired side and saw that the ferret again turned in the direction it had associated with lights.
Term
An enriched environment promotes growth of axons and dendrites. What is known to be one important reason for this effect?
Definition
Animals in an enriched environment are more active, and their exercise enhances growth of axons and dendrites.
Term
Name two kinds of evidence indicating that touch information from the fingers invades the occipital cortex of people blind since birth?
Definition
First, brain scans indicate increased activity in the occipital cortex while blind people perform task such as feeling two objects and saying whether they are the same of different. Second, temporary inactivation of the occipital cortext blocks blind peoples ability to perform that task, without affecting the ability of sighted people
Term
Which brain area shows expanded representation of the left hand in people who began practicing stringed instruments in childhood and continued for many years?
Definition
Postcentral gyrus of the right hemisphere
Term
What change in the brain is responsible for musician's cramp?
Definition
Extensive practice of violin, piano, or other instruments causes expanded representation of the fingers in the somatosensory cortex. In some cases, the representation of each finger invades the area representing other fingers. If the representation of two fingers overlaps to much, the person cannot feel them separately, and the result is a musician's cramp.
Term
Of the following, which use a labeled-line code and which use an across-fiber pattern code?
a) a fire alarm
b) a light switch
c) typing a capital letter
Definition
Typing a capital letter is an example of an across-fiber pattern code. (The result depends on a combination of the letter key and the shift key.) A fire alarm and a light switch are labeled lines that convey only one message.
Term
Suppose you find a new, unusual-tasting food. How could you determine whether we have a special receptor for that food or whether we taste it with a combination of the other known taste receptors?
Definition
You could test for cross-adaptation. If the new taste cross-adapts with others, then it uses the same receptors. If it does not cross-adapt, it may have a receptor of its own. Another possibility would be to find some procedure that blocks this taste without blocking other tastes.
Term
Although the tongue has receptors for bitter tastes, researchers have found neurons in the brain itself that respond more strongly to bitter than to other tastes. Explain, then, how it is possible for the brain to detect bitter tastes?
Definition
Two possibilities: First, bitter tastes produce a distinctive temporal pattern of responses in cells sensitive to taste. Second, even if no one cell responds strongly to bitter tastes, the pattern of responses across many cells may be distinctive. Analogously, in vision, no cone responds primarily to purple, but we nevertheless recognize purple by its pattern of activity across a population of cones
Term
If someone injected into your tongue a chemical that blocks the release of second messengers, how would it affect your taste experience?
Definition
The chemical would block your experiences of sweet, bitter, and unami but should not prevent you from tasting salty and sour.
Term
How do hormones influence taste sensitivity?
Definition
Genes and hormones influence the number of taste buds near the tip of the tongue.
Term
How do olfactory receptors resemble metabotropic neurotransmitter receptors?
Definition
Like metabotropic neurotransmitters receptors, an olfactory receptor acts through a G-protein that triggers further events within the cell.
Term
What is the mean life span of an olfactory receptor?
Definition
Most olfactory receptors survive a little more than a month before dying and being replaced
Term
What good does it do for an olfactory axon to have copies of the cell's olfactory receptor protein?
Definition
the receptor molecule acts as a kind of identification to help the axon find its correct target cell in the brain.
Term
What is one major difference between olfactory receptors and those of the vomeronasal organ?
Definition
Olfactory receptors adapt quickly to a continuous odor, whereas receptors of the vomeronasal organ continue to respond. Also, vomeronasal sensations are apparently capable of influencing behavior even without being consciously perceived.
Term
If someone reports seeing a particular letter in color, in what way is it different from a real color?
Definition
Someone who perceives a letter as yellow ( when it is actually in black ink) can nevertheless see it on a yellow page.
Term
What evidence led Sherrington to conclude that transmission at a synapse is different from transmission along an axon?
Definition
Sherrington found that the velocity of conduction through a reflex arc was significantly slower than the velocity of an action potential along an axon. Therefore, some delay must occur at the junction between one neuron and the next.
Term
What us the difference between temporal summation and spatial summation?
Definition
Temporal summation is the combined effect of quickly repeated stimulation at a single synapse. Spatial summation is the combined effect of several nearly simultaneous stimulation at several synapses onto one neuron.
Term
What was Sherrington's evidence for inhibition in the nervous system?
Definition
Sherrington found that a reflex that stimulates a flavor muscle sends a simultaneous message that inhibits nerves to the extensor muscles of the same limb.
Term
What ion gates in the membrane open during EPSP? What gates open during an IPSP?
Definition
During EPSP, voltage gated sodium channels open. During an IPSP, potassium or voltage gated chloride channels open
Term
Can an inhibitory message propagate along an axon?
Definition
No. Only action potentials propagate along an axon. Both EPSP's and IPSP's decay rapidly over time and distance. Their function is to determine whether the axon will send an action potential.
Term
What was Loewi's evidence that neurotransmission depends on the release of chemicals?
Definition
When Loewi stimulated a nerve that increased or decreased a frog's heart rate, he could withdraw some fluid from the area around the heart, transfer it to another frog's heart, and thereby increase or decrease its rate also.
Term
What does a highly active brain area do, in many cases, to increase its blood supply?
Definition
In a highly active brain area, many stimulated neurons release nitric oxide, which dilates the blood vessels in the area and thereby increases blood flow to the area.
Term
Name the three catecholamine neurotransmitters.
Definition
Epinephrine, norepinephrine, and dopamine
Term
When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neuro-transmitter?
Definition
Calcium
Term
How do ionotropic and metabotropic synapses differ in speed and duration of effects?
Definition
Ionotropic synapses act more quickly and more briefly
Term
What are second messengers, and which type of synapse relies on them?
Definition
At metabotropic synapses, the neurotransmitter attaches to its receptor and thereby releases a chemical(the secondary messenger) within the postsynaptic cell, which alters metabolism or gene expression of the postsynaptic cell.
Term
Which part of the pituitary; anterior or posterior; is neural tissue, similar to the hypothalamus? Which part is glandular tissue and produces hormones that control the secretions by endocrine organs?
Definition
The posterior pituitary is neural tissue, like the hypothalamus. The anterior pituitary is glandular tissue and produces hormones that control several other endocrine organs.
Term
In what way is a neuropeptide intermediate between other neurotransmitters and hormones?
Definition
Most neurotransmitters are released in small amounts close to their receptors. Neuropeptides are released into a brain area in larger amounts or not at all. When released, they diffuse more widely. Hormones are released into the blood for diffuse delivery throughout the body.
Term
What happens to acetylcholine molecules after they stimulate a post synaptic receptor?
Definition
The enzyme acetylcholinesterase breaks acetylcholine molecules into two smaller molecules, acetate and choline, which are then reabsorbed by the presynaptic terminal
Term
What happens to serotonin and catecholamine molecules after they stimulate a post synaptic receptors?
Definition
Most serotonin an catecholamine molecules are reabsorbed by the presynaptic terminal. Some of their molecules are broken down into inactive chemicals, which then float away.
Term
Is a drug with high affinity and low efficacy an agonist or antagonist?
Definition
Such a drug is an antagonist because, by occupying the receptor, it blocks out the neurotransmitter.
Term
What do drug use, sex, gambling, and video game playing have in common?
Definition
They increase the release of dopamine in the nucleus accumbens.
Term
How does amphetamine influence dopamine synapses?
Definition
Amphetamine causes the dopamine transporter to release dopamine instead of reabsorbing it.
Term
How does cocaine influence dopamine synapses?
Definition
Cocaine interferes with re-uptake of released dopamine.
Term
Why is methylphenidate generally less disruptive to behavior than cocaine is despite the drugs' similar mechanisms?
Definition
The effects of a methylphenidate pill develop and decline in the brain much more slowly than do those of cocain.
Term
How does nicotine affect dopamine synapses?
Definition
Nicotine excites acetylcholine receptors on neurons that release dopamine and thereby increases dopamine release.
Term
How do opiates influence dopamine synapses?
Definition
Opiates stimulate endorphin synapses, which inhibit neurons that inhibit release of dopamine. By inhibiting an inhibitor, opiates increase the release of dopamine.
Term
What are the effects of cannabinoids on neurons?
Definition
Cannabinoids released by the postsynapti ceuron attach to receptors on presynaptic neurons, where they inhibit further release of glutamate as well as GABA.
Term
If incoming serotonin axons were destroyed, LSD would still have its full effects. However, if incoming dopamine axons were destroyed, amphetamine and cocaine would lose their effects. Explain the difference.
Definition
Amphetamine and cocaine act by releasing the net release of dopamine and other transmitters. If those neurons were damaged, amphetamine and cocaine would be ineffective. In contrast, LSD directly stimulates the receptor on the postsynaptic membrane.
Term
Which type of alcoholism has a stronger genetic basis? Which type has earlier onset?
Definition
In both cases, type II.
Term
Name at least two ways a gene could influence alcoholism.
Definition
Genes can influence alcoholism by producing less sensitive dopamine receptors, faster breakdown of dopamine by the enzyme COMT, greater risk-taking behavior, and altered responses to stress. Of course, other possibilities not mentioned in this section also exist.
Term
What are two ways sons of alcoholics differ, on average, from sons of non-alcoholics?
Definition
Sons of alcoholics show less intoxication, including less body sway, after drinking moderate amount of alcohol. They also show greater relief from stress after drinking alcohol.
Term
Someone who has quit an addictive substance for the first time is strongly counseled not to try it again. Why?
Definition
Taking an addictive drug during the withdrawal period is strongly reinforcing and likely to lead to prolonged use.
Term
When addiction develops, how does the nucleus accumbens change its response to the addictive activity and to other reinforcements?
Definition
The nucleus accumbens becomes selectively sensitized, increasing its response to the addictive activity and decreasing its response to other reinforcing activities.
Term
Who would be likely to drink more alcohol; someone who metabolizes acetaldehyde to acetic acid rapidly or one who metabolizes it slowly?
Definition
People who metabolize it rapidly would be more likely to drink alcohol because they suffer fewer unpleasant effects.
Term
How does Antabuse work?
Definition
Antabuse blocks the enzyme that converts acetaldehyde to acetic acid and therefore makes people sick if they drink alcohol. Potentially, it could teach people an aversion to alcohol, but more often it works as a way for the person to make a daily re-commitment abstain from drinking.
Term
Methadone users who try taking heroin experience little effect from it. Why?
Definition
Because methadone is already occupying the endorphin receptors, heroin cannot add much stimulation to them.
Term
Gradient of Chemicals
Definition
One way that axons are attracted to an intermediate location where they become insensitive to that chemical and start following a different attractant
Term
Natural Darwinism
Definition
In the development of the nervous system, we start with more neurons and synapses than we keep. Synapses form haphazardly, and then a selection process keeps some and rejects others.
Term
What did Levi-Montcalcini discover?
Definition
Nevertheless, she developed a love for research and eventually discovered that the muscles do not determine how many axons form; they determine how many survive.
Term
Nerve Growth Factor (NGF)
Definition
When one of its neurons forms a synapse onto a muscle, that muscle delivers a protein called (NGF) that promotes the survival and growth of the axon. An axon that does not receive NGF degenerates, and its cell body dies.
Term
Apoptosis
Definition
If a axon does not make contact with an appropriate postsynaptic cell by a certain age, the neuron kills itself through a process called apoptosis, a programmed mechanism of cell death. NGF cancels the program for apoptosis.
Term
Neurotrophin
Definition
Nerve growth factor, a chemical that promotes the survival and activity of neurons.
Term
brain-derived neurotropic factor(BDNF)
Definition
In addition to NGF, the nervous system responds to BDNF and several other neurotrophins. BDNF is the most abundant neurotrophin in the adult cerebral cortex.
Term
Fetal Alcohol Syndrome
Definition
Children of mothers who drink heavily during pregnancy are born with Fetal Alcohol Syndrome, a condition marked by hyperactivity, impulsiveness, difficulty maintaining attention, varying degrees of mental retardation, motor problems, heart defects, and facial abnormalities.
Term
Fetal Alcohol Syndrome (ADULTS)
Definition
They have increased risk of alcoholism, drug dependence, depression, and psychiatric disorders.
Term
What happens to children of mothers that used cocaine during pregnancy?
Definition
Showed a decrease in language skills compared to other children, a slight decrease in IQ scores, and impaired hearing.
Term
What happened to children of mothers who smoked during pregnancy?
Definition
they are at increased risk of attention deficit disorder, aggressive behavior, and impaired memory and intelligence.
Term
What does a higher enriching environment develop?
Definition
It developed a thicker cortex, more dendritic branching, and improved learning.
Term
What happens to the cerebral cortex and Neurons in general beginning at age 30?
Definition
The cerebral cortex declines with advancing age, beginning at age 30 and accelerating in later years. Neurons also become less active, partly because of decreased blood flow.
Term
Focal Hand Dystonia
Definition
The condition called musicians cramp in which the fingers become clumsy, fatigue easily, and make involuntary movements that interfere with the task.
Term
Labeled-Line Principle
Definition
each receptor would respond to limited range of stimuli
Term
Across-Fiber Patterns Principle
Definition
each receptor responds to a wider range of stimuli
Term
Taste Buds
Definition
The receptors on the tongue
Term
Papillae
Definition
Location of mammalian taste receptors on the surface of the tongue
Term
Adaptation
Definition
When the body adapts to a strong stimuli making a similar stimuli weaker.
Term
Cross Adaptation
Definition
reduced response to one taste after exposure to another
Term
Supertasters
Definition
have the highest sensitivity to all taste and mouth sensations.
Term
What do the variations in taste sensitivity relate to?
Definition
the number of fungigorm papillae
Term
Olfaction
Definition
the sense of smell, is the response to chemicals that contact the membranes inside the nose.
Term
Olfactory Cells
Definition
The neurons responsible for smell. They line the olfactory epithelium in the rear of the nasal air passages.
Term
Olfactory Cells
Definition
The neurons responsible for smell. They line the olfactory epithelium in the rear of the nasal air passages.
Term
Which gender detect odor more readily? Which gender has a stronger brain response to odor?
Definition
Women
Term
Pheromones
Definition
Are chemicals released by an animal that affect the behavior of other members of the same species, especially sexually
Term
Vomeronasal Organ (VNO)
Definition
Is a set of receptors located near, but separate from, the olfactory receptors.
Term
Do your olfactory receptors respond to continued odors?
Definition
No. Your olfactory receptors respond to a new odor but not to a continued one.
Term
Synesthesia
Definition
Is the experience of one sense in response to stimulation of a different sense.
Term
Synapses
Definition
Neurons communicate by transmitting chemicals at specialized junctions called synapses
Term
Reflexes
Definition
automatic muscular responses to stimuli
Term
Leg Flexion Reflex
Definition
a sensory neuron excites a second neuron, which in turn excites a motor neuron which in turn excites a muscle.
Term
Reflex Arc
Definition
The circuit from sensory neuron to muscle response
Term
Sherringtons Observations on Reflexes and Special processes at the junction between neurons
Definition
A)Reflexes are slower than conduction along and axon
B)Several weak stimuli presented at slightly different times or slightly different locations produce a stronger reflex than a single stimulus dose.
c)When one set of muscles become excited, a different set becomes relaxed.
Term
Temporal Summation
Definition
Repeated stimuli within a brief time have a cumulative effect. In a single location.
Term
Graded Potentials
Definition
Unlike action potentials, which are always depolarization's, graded potentials may either be depolarization's(excitatory) or hyperpolarizations(inhibitory)
Term
Excitatory Postsynaptic Potential
Definition
A graded depolarization. An EPSP occurs when sodium ions enter the cell. If an EPSP does not cause the cell to reach its threshold, depolarization decays quickly.
Term
Spatial Summation
Definition
Summation over space.
Synaptic input from separate locations combine their effect on a neuron.
Spacial Summation is critical to brain function
Term
What does spacial summation assure?
Definition
That a sensory stimulus will stimulate the cortical cells enough to activate them
Term
Internuron
Definition
an intermediate neuron in the spinal chord
Term
Inhibitory postsynaptic potential
Definition
The temporary hyperpolarization of a membrane after an action potential or graded potential . Selectively opens voltage gates to allow potassium to leave and or chloride to enter.
Term
Spontaneous Firing Rate
Definition
a periodic production of action potentials even without synaptic input
Term
Spontaneous Firing Rate
Definition
a periodic production of action potentials even without synaptic input
Term
What is step one in the sequence of chemical events at the synapse?
Definition
1)The neuron synthesizes chemicals that serve as neurotransmitters. It synthesizes the smaller neurotransmitters in the axon terminals and neuropeptides in the cell body
Term
What is step two in the sequence of chemical events at the synapse?
Definition
2)The neuron transports the neuropeptides that were formed in the cell body to the axon terminals or to the dendrites. (Neuropeptides are released from multiple sites in the cell)
Term
What is step three in the sequence of chemical events at the synapse?
Definition
Action potential travels down the axon. At the presynaptic terminal, an action potential enables calcium to enter the cell through voltage gated channels. Calcium releases neurotransmitters from the terminals and into the synaptic cleft
Term
Synaptic cleft
Definition
the space between the presynaptic and postsynaptic neurons.
Term
What is step four in the sequence of chemical events at the synapse?
Definition
The released molecules diffuse across the cleft, attach to receptors, and alter activity of the postsynaptic neuron.
Term
What is step five in the sequence of chemical events at the synapse?
Definition
The neurotransmitter molecules separate from their receptors. Depending on the neurotransmitter, it may be converted into inactive chemicals.
Term
What is step six in the sequence of chemical events at the synapse?
Definition
The neurotransmitter molecules may be taken back into the presynaptic neuron for recycling or may diffuse away. In some cases, empty vesicles are returned to the cell body.
Term
What is step seven in the sequence of chemical events at the synapse?
Definition
Some postsynaptic cells send reverse messages to control the further release of neurotransmitter by presynaptic cells.
Term
Where are the most abundant neurotransmitters synthesized?
Definition
In the preynaptic terminal
Term
Where are neuropeptides synthesized?
Definition
In the cell body and then transported down the axon or into the dendrites
Term
Vesicles
Definition
A tiny spherical packets where the presynaptic terminal stores high concentrations of neurotransmitters molecules
Term
Exocytosis
Definition
Release of neurotransmitter in bursts from the presynaptic neuron into the synaptic cleft.
Term
Ionotropic Effects
Definition
When the neurotransmitter binds to a receptor on a membrane, it opens the voltage gated channel for some type of ion.
Term
Ligand Gated
Definition
a gate operated by a chemical that binds to another chemical
Term
What neurotransmitters are most of the brains excitatory ionotropic synapses using?
Definition
Glutamate
Term
What neurotransmitter do most inhibitory synapses use?
Definition
GABA
Term
GABA
Definition
opens chloride gates, enabling chloride ions, with their negative charge, to cross the membrane into the cell more rapidly than usual
Term
Metabotropic effects
Definition
a sequence of metabolic reactions that are slower and longer lasting ionotropic effects
Term
G-protein
Definition
a energy storing molecule that increases the concentration of a second messenger
Term
Second Messenger
Definition
Just as the first messenger(the neurotransmitter), it carries information to the postsynaptic cell, to communicate to areas within the cell.
Term
Hormone
Definition
a chemical that is secreted, in most cases by a gland but also by other kinds of cells, and conveyed by the blood to other organs, whose activity it influences.
Term
Releasing Hormones
Definition
flow through the blood to the anterior pituitary. There they stimulate or inhibit release of hormones
Term
Reuptake
Definition
The presynaptic neuron takes up most of the released neurotransmitters molecules intact and reuses them
Term
autoreceptors
Definition
receptors that detect amount of transmitter released and inhibit further synthesis and release after it reaches a certain level
Term
Antagonist
Definition
A drug that blocks the effects of a neurotransmitter
Term
Agonist
Definition
A drug that mimics or increases the effects
Term
Efficacy
Definition
Is the tendency of a drug to activate a receptor
Term
Affinity
Definition
if a drug is capable of binding to a receptor
Term
Stimulant Drugs
Definition
increase excitement, alertness, and activity, while elevating mood and decreasing fatigue
Term
What does cocaine do?
Definition
It blocks the reuptake of dopamine, norephinephrine, and serotonin, thus prolonging their effects
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