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69 terms

Chapter 12 - Unit 6

neural integration
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neural integration
the ability of your neurons to process information, store and recall it and make decisions
excitatory postsynaptic potential (EPSP)
usually results from Na+ flowing into the cell and cancelling some of the negative charge on the inside of the membrane
inhibitory postsynaptic potential (IPSP)
some are produced by a neurotransmitter opening ligand-regulated chloride gates causing Cl- to flow into the cell and make the cytosol more negative
EPSP
any voltage change in that direction makes a neuron more likely to fire and is therefore called
IPSP
a neurotransmitter hyperpolarizes the postsynaptic cell and makes it more negative than the RMP - this makes the postsynaptic cell less likely to fire
chemical synapses
are the decision making devices of the system.
glutamate and aspartate
are excitatory brain neurotransmitters that produce EPSPs.
glycine and GABA
produce IPSPs and are therefore inhibitory
ACh and norepinephrine
are excitatory to some and inhibitory to others, depending on the type of receptors present on the target cell
EPSP, IPSP
Some incoming nerve fibers produce __________, while others produce _____________.
net
The neuron's response depends on whether the ________ input is excitatory or inhibitory.
Summation
is the process of adding up post synaptic potentials and responding to their net effect
trigger zone
Summation occurs in the ______________
decisions
It is fundamentally a balance between EPSPs and IPSPs that enable the nervous system to make ________.
single action potential
A __________ in a synaptic knob does not produce enough activity to make a postsynaptic cell fire.
temporal summation and spatial summation
There are two ways to reach threshold and cause a postsynaptic neuron to fire
temporal summation
occurs when a single synapse generates EPSPs so quickly that each is generated before the previous one fades
spatial summation
occurs when EPSPs from several different synapses add up to threshold at the axon hillock.
groups
Neurons routinely work in ___________ to modify each other's actions.
facilitation
is a process in which one neuron enhances the effect of another.
presynaptic inhibition
is the opposite of facilitation, it is the mechanism in which one presynaptic neuron supresses another one.
qualitative, quantitative
The nervous system myst interpret and pass along both ______________ and ____________ information about its environment.
neural coding
the way in which the nervous system converts information to a meaningful pattern of action potentials is called _______________.
sensory coding
another name for neural coding
labeled line code
the most important mechanism for transmitting qualitative information is the ______________.
labeled line code
is based on the fact that each nerve fiber to the brain leads from a receptor that specifically recognizes a particular stimulus type
communication
Each nerve fiber to the brain is a line of __________ recognized by the brain, as representing a particulr stimulus quality - the color of light, pitch of sound, salty or sour taste.
Quantitative information
information about the intensity of the stimulus
recruitment
bringing additional neurons into play as the stimulus becomes stronger is called...
absolute refractory period
there is a limit to how often a neuron can fire, set by its __________________.
lowest, high threshold
A weak stimulus excites neurons with the __________ thresholds, while a strong stimulus excitesless sensitive _____________ neurons.
CNS
The __________ can judge stimulus strength from the firing frequency of afferent neurons.
mild stimulus
A _______________ excites sensitive low-threshold nerve fibers.
neural pools
neurons function in larger ensembles called __________ each of which consists of thousands to millions of interneurons concerned with a particular body function.
discharge zone
part of input neuron when acting alone can make the post synaptic cells fire
facilitated zone
broader zone where the neurons synapses with still other neurons in the pool with fewer synapses on each of them. it can stimulate those neurons to fire only with the assistance of other input neurons
facilitated zone
In _______________ the presynaptic neuron lacks enough synaptic contacts with a postsynaptic neuron to induce firing by itself -- but it can collaborate with other presynaptic neurons, facilitating each other in making the postsynaptic cell fire
discharge zone, spatial summation
In the _____________ the presynaptic input neuron has so many synaptic contacts with each postsynaptic neuron that it alone can induce the postsynaptic cell to fire, employing ____________.
neural circuit
The functions of a neural pool are partly determined by its ______________ the pathways among its neurons.
diverging circuit, converging circuit, reverberating circuit, parallel after-discharge circuit
Name the four principal kinds of neural circuits.
diverging circuit
one nerve fiber branches and synapses with several poststynaptic cells
diverging circuit
this type of neural circuit makes it possible for one motor neuron of the brain to ultimately stimulate thousands of muscle fibers.
converging circuit
is the opposite of a diverging circuit - input from many different nerve fibers is funneled to one neuron or neuron pool
converging circuit
this type of neural circuit allows input from our eyes, inner ears and stretch receptors in the neck to be channed to an area of teh brain concerned with the sense of balance.
reverberating circuit
neurons stimulate each other in a linear sequence A-->B-->C-->D, but neuron C sends an axon collateral back to A and restimulates
parallel after-discharge circuit
an input neuron diverges to stimulate several chains of neurons
reverberating circuit
this type of neural circuit sends repetitious signnals to your diaphragm and intercostal muscles to make you inhale
parallel after-discharge circuit
this type of neural circuit explains why you can stare at a lamp, then close your eyes and continue to see an image for a while
feedback loop
Unlike a reverberating circulit, parallel after-discharge circuit has no _______________.
after-discharge
Continued firing after the stimulus stops is called _____________.
memory trace (engram)
The physical basis of memory is a pathway through the brain called a _________________ in which new synapses have formed or existing synapses have been modified to make transmission easier.
synaptic plasticity
synapses can be formed or deleted in as little as 1 to 2 hours, this ability of synapses to change is called ___________.
synaptic potentiation
a form of synaptic plasticity - the process of making transmission easier.
immediate, short term, long term
Name 3 most recognizeable forms of memory
immediate memory
is the ability to hold something in mind for just a few seconds
immediate memory
this form of memory might be based on reverberating circuits
short-term memory
lasts from a few seconds to a few hours
working memory
is a form of STM that allows us to hold an idea in mind long enough to carry out an action such as calling a telephone # we just looked up or working out the steps of a math problem.
synaptic facilitation
somewhat longer lasting memories probably involve an effect called _________________-induced by tetanic stimulation, the rapid arrival of repetitive signals at a synapse.
posttetanic potentiation
The increased size of postsynaptic membrane potentials after tetanic stimulation.
long term memory
lasts up to a lifetime and is less limited than STM in the amount of information it can store.
declarative and procedural
List the 2 forms of long-term memory
declarative memory
the retention of events and facts that you can put into words - numbers, dates, and so forth
procedural memory
the retention of motor skills - how to tie your shoes, play a musical instrument,
LTM
Some ___________ involves the physical remodeling of synapses or the formation of new ones through the growth and branching of axon terminals and dendrites.
dendritic spines
In the pyramidal cells of the brain, the dendrites are studded with knob-like ____________ that increase the area of synaptic contact.
long-term potentiation
LTM can also be grounded in molecular changes called ____________________.
long-term potentiation
An increase in a synapse's firing potential after brief, rapid stimulation. Believed to be a neural basis for learning and memory.
Alzheimer and Parkinson diseases
are the two most common degenerative disorders of the brain. Both are associated with neurotransmitter deficiencies.