Psychology 118 (Ch. 5) Vocab.

Front 1

action potential (AP)

Back 1

an all-or-none electrochemical potential transmitted through the neuron's axon at constant speed and amplitude.

Front 2

below-zero habituation

Back 2

habituation involves the complete elimination of a particular response (i.e, zero frequency of occurrence). If the stimulus cintinues to be presented for an additional number of trials, then, although no further changes occur, the response will exhibit lower levels of recovery (e.g, spontaneous recovery is reduced) as if the response would have fallen below a zero frequency.

Front 3

brain

Back 3

an anterior enlargement of the CNS. In vertebrates, the size (weight or volume) of the brain can, in some cases, be meausred or estimated from fossil crania, an important source of data for an understanding of brain evolution.

Front 4

central and peripheral nervous system

Back 4

the central nervous system (CNS) includes the neural tissue located in the ganglia (invertebrates) or in the brain and spinal cord (vertebrates). it is distinguished from the peripheral nervous system, a set of nerves that connect the CNS with receptors, organs, and glands in the periphery of the body.

Front 5

central pattern generator (CPG)

Back 5

a neural network that controls a sequentially organized series of behaviors without relying on sensory feedback from each individual component.

Front 6

chemical synapse

Back 6

in a chemical synapse, the arrival of an action potential at the axon terminal causes the release of a neurotransmitter.

Front 7

collagen

Back 7

a fibrous protein found in the intercellular space of all animals.

Front 8

command neuron

Back 8

a unit, or a small network, responsible for activating a pattern of behavior.

Front 9

depolarization

Back 9

a change in the resting potential of a neuron that makes the interior of the cell electrically less negative or positive, in relation to the extracellular space.

Front 10

diffuse nervous system

Back 10

the nervous system of cnidarians is dispersed in the body without a clear differentiation between central and peripheral systems.

Front 11

dishabituation

Back 11

a resurgence of a habituated response after the presentation of a novel, relatively intense stimulus.

Front 12

electrical synapse

Back 12

a synapse in which the electrochemical potential crosses directly from the presynaptic to the postsynaptic neuron, without neurotransmitter release.

Front 13

excitatory and inhibitory postsynaptic potentials (EPSP and IPSP)

Back 13

a depolarizing (EPSP) or hyperpolarizing (IPSP) gradual potential induced in the postsynaptic neuron by the release of neurotransmitter by the presynaptic neuron.

Front 14

fossil traces

Back 14

marks left by moving animals that fossilized in sedimentary rocks.

Front 15

functional disconnection

Back 15

a reduction in the efficacy of a synapse as a result of habituation training.

Front 16

ganglia

Back 16

clusters of neuron in the CNS of invertebrates (singular: ganglion).

Front 17

generalization of habituation

Back 17

habituation to a stimulus that transfers to other stimuli in direct proportion to their degree of similarity.

Front 18

giant neurons

Back 18

neurons of large size that have served as models to understand the neuron's electrochemical properties (e.g, the squid's giant axon).

Front 19

graded potentials

Back 19

a change in the electrochemical potential of a neuron proportional to the stimulus that provoked it.

Front 20

habituation

Back 20

a decrease in the response to a stimulus that results from its repetitive presentation. the short-term version of this effect is considered to be an example of nonassociative learning. long-term habituation may involve associative learning between the habituating stimulus and the contextual cues present at the time of training.

Front 21

habituation of dishabituation

Back 21

the degree of response recovery that will tend to diminish when a response is repeatedly dishabituated.

Front 22

habituation of habituation

Back 22

a period of rest after habituation of a response that results in the spontaneuous recovery of that response. if, however, several such resting periods are introduced, response recovery decreases.

Front 23

heterosynaptic facilitation

Back 23

the facilitation of transmission through a synapse as a result of a third neuron modifying the excitability of the presynaptic neuron via an axo-axonic synapse. heterosynaptic facilitation has been proposed as the mechanism underlying some instances of dishabituation.

Front 24

homosynaptic depression

Back 24

a decrease in the excitability of a synapse. homosynaptic depression has been proposed as a mechanism underlying some instances of short-term habituation.

Front 25

hyperpolarize

Back 25

action potentials cause the interior of the postsynaptic neuron to become more negative than it is during a resting potential.

Front 26

increased excitability

Back 26

an ability exhibited by some neurons to increase the amount of neurotransmitter released in the synapse by lengthening the time during which calcium channels remain open. increased excitability has been proposed as a mechanism underlying some instances of dishabituation.

Front 27

interstimulus interval (ISI) effect

Back 27

the shorter the interstimulus unterval (ISI), the faster the habituation.

Front 28

learning (associative and nonassociative)

Back 28

acquiring, storing, and retrieving information that results from experience. these processes occur in the CNS. Associative learning results from a single occurence or from repeated experience with two or more events that occur in temporal or spatial contiguity. nonassociative learning occurs when organisms modify their response to a single event after repeated presentations.

Front 29

learning-performance dichotomy

Back 29

learning must not be equated with performance or behavior. this is particularly umportant when dealing with putative instances of learning failure. the absence of a behavior does not imply the absence of learning.

Front 30

long-term habituation

Back 30

habituation that persists for more than 24h

Front 31

modal action pattern (MAP)

Back 31

sequentially organized behaviors that, once activated, develop in a more or less ballistic manner. MAPs are said to be species-typical behaviors.

Front 32

monosynaptic reflex

Back 32

a reflex are based on two neurons and a single synapse (a sensory-motor synapse).

Front 33

muscular fatigue

Back 33

exhaustion of the muscles (after repeated stimultion)resulting in the inability to perform a response.

Front 34

nematocyst

Back 34

a coiled structure present in cnidarians (e.g, jellyfish) that can be released to seize a prey.

Front 35

neurotransmitter

Back 35

a chemical sunstance released at the axon's terminals by an incoming action potential. neurotransmitters diffuse in the synapse and reach the membrane of the postsynaptic neuron, where they activate specific receptors. such activation may induce gradual potentials in the postsynaptic neuron.

Front 36

one-zero sampling

Back 36

an observational procedure that consits of determining the presence (one) versus the absence (zero) of a particular behavior during a specific time interval.

Front 37

peripheral reflex arc

Back 37

a reflex are completely organized at the periphery, capable of functioning, even when seperated from the CNS.

Front 38

plastic synapse

Back 38

a synapse that can change its strength based on use.

Front 39

polysynaptic reflex

Back 39

a reflex arc that includes sensory neurons, motor neurons, and interneurons.

Front 40

reflex arc

Back 40

a basic unit of behavior involving a sensory input, a processing section in the CNS, and an output.

Front 41

reflex chain

Back 41

a neural network that control a sequence of responses based on the sensory feedback provided by each element in the sequence.

Front 42

resting potential

Back 42

the electrochemical potential of a nonstimulated neuron.

Front 43

sensitization

Back 43

an increase in the strength of a response as a result of the repeated presentation of a relatively intense stimulus. whereas the short-term sensitization effect is generally thought to be an instance of nonassociative learning, the nature of the long-term sensitization effect is not yet well understood.

Front 44

sensory adaptation

Back 44

as a result of repeated stimulation, a sensory receptor may decrease or even stop firing in response to a stimulus.

Front 45

short-term habituation

Back 45

habituation that lasts for a period of time in the order of minutes to a few hours.

Front 46

simple systems approach

Back 46

a research strategy based on the selection of a relatively simple instance of behavior and a simple neural circuit to understand the cellular basis of behavior.

Front 47

spike broadening

Back 47

the slowing down of potassium outflow by some neurons tht lenghtens the time during when a neurotransmitter is released after an action potential. spike broadening has been proposed as a mechanism underlying some instances of sensitizations.

Front 48

spontaneous recovery

Back 48

in habituation or extinction experiments, a resurgence of the response following a period of rest introduced after the response being measured has decreased in strength.

Front 49

stimulus intensity effect

Back 49

habituation is an inverse function of the intensity of the habituating stimulus. however, in other forms of learning, acquisition is usually a direct function of the intesity or magnitude of the stimuli involved.

Front 50

synaptic plasticity

Back 50

the capacity of some neurons to modify their synaptic functioning as a result of use and disuse.