Ch13 - Combining fMRI with other techniques

Question 1

converging operations

Answer 1

employing 2+ techniques to provide complementary evidence used to test an experimental hypothesis or scientific theory

Question 2

constructs

Answer 2

abstract concept that explains behavior but that itself is not directly observable
- e.g. psychological constract

Question 3

isomorphic

Answer 3

having an identical form
- a physiological measurement that is isomorphic with psychological construct would vary over time consistently with postulated changes in the construct

Question 4

localization of function

Answer 4

idea that brain may have distinct regions that support particular mental process

Question 5

functional connectivity

Answer 5

pattern of functional relationships among regions, inferred from common changes in activation over time
- may reflect direct or indirect links between these regions

Question 6

direct cortical stimulation

Answer 6

applying small currents directly to brain tissue to excite or disrupt neural activity
- usually contucted in humans to localize critical brain regions in context of neurosurgery

Question 7

transcranial direct current stimulation

Answer 7

(tDCS)
inexpensive and safe neuroscience technique using weak electrical current that passes through brain
- changers excitability of neurons and alters brain function

Question 8

equipotentiality

Answer 8

concept that a function is so widely distributed within brain that activity depends on whole brain
- antithesis of localization of function

Question 9

anode

Answer 9

source of positive charge or ions and attractor of free electrons

Question 10

cathode

Answer 10

attractor for positive charge/ions and source of free electrons

Question 11

homotopic

Answer 11

cortex in one cerebral hemisphere corresponds to same region in other hemisphere

Question 12

single-pulse TMS

Answer 12

delivery of single TMS stimulation pulse to disrupt some ongoing brain process

Question 13

repetitive TMS

Answer 13

delivery of extended series of closely spaced TMS stimulation pulses to effect long-lasting changes in brain function
- may lead to indirect changes in brain physiology by increased excitability/inhibition of area
- applied for e.g. chronic neurological and psychiatric conditions

Question 14

single dissociation

Answer 14

demonstration that an experimental manipulation has an effect on one variable but not a second

Question 15

double dissociation

Answer 15

demonstration that 2 experimental manipulations have different effects on 2 dependent variables. Manipulation A affects X but not Y, Manipulation B affects Y but not X

Question 16

registry

Answer 16

patient database

Question 17

plasticity

Answer 17

change in normal functional properties of brain tissue following injury or experience

Question 18

recovery of function

Answer 18

improvement in previously impaired ability over time due to functional/structural changes within brain

Question 19

polymorphism

Answer 19

common variation in a gene or segmant of DNA

Question 20

imaging genomics

Answer 20

field that investigates effect of genetic variation on brain structure and function

Question 21

action potential

Answer 21

wave of depolarization that travels down neuronal axon

Question 22

electrogenesis

Answer 22

generation of electrical electrophysiological phenomena by living organism

Question 23

single-unit recording

Answer 23

collection of data about electrophysiological activity of single neuron

Question 24

field potentials

Answer 24

changes in electrical potential over space associated with postsynaptic neuronal activity

Question 25

recepive field

Answer 25

part of visual field that, when stimulated, will result in an increase in firing of particular neuron

Question 26

simple cell

Answer 26

neuron in visual cortex that responds with increased firing to stimulus with preferred orientation in its receptive field decreased firing when stimulus in surroundings of receptive field - central rectangular region

Question 27

complex cell

Answer 27

neuron in visual cortex with larger receptive field than simple cell that responds to stimulus with preferred orientation anywhere withing receptive field

Question 28

ion

Answer 28

atom or molecule that carries electrical charge

Question 29

pump

Answer 29

transport system that moves ions across cell membrane against concentration gradient

Question 30

current sink

Answer 30

attractor of positive ions - depolarized patch of neuronal membrane is a current sink because positively charge ions will flow towards it

Question 31

current source

Answer 31

source of positive ions

Question 32

primary current

Answer 32

current flow within neuron caused by inflow of ions through ionic channels opened by synaptic activity

Question 33

volume conducter

Answer 33

continuously conductive medium - brain, meninges, skull, scalp constitute of a volume conductor throughout which currents created by ionic flow can be measured

Question 34

volume current

Answer 34

return current through extracellular medium that balances the primary current within neuron

Question 35

current dipole

Answer 35

idealized pairing of current source and current sink separated by infinitesimal distance - used as a simple convenient model for electromagnetic fields produced by activated neuron

Question 36

apical dendrites

Answer 36

dendrites that are distant from the neuronal cell body - e.g: pyramidal cells - dendrites extend all the way to the cortex

Question 37

equivalent dipole

Answer 37

simplified model that represents the electromagnetic field produced by population of neurons as though it were produced by single dipole

Question 38

polysynaptic potential

Answer 38

(PSP) Any postsynaptic potential that results from synaptic activity

Question 39

excitiatory postsynaptic potential

Answer 39

(EPSP) depolarization of postsynaptic cell membrane

Question 40

inhibitory postsynaptic potential

Answer 40

(IPSP) hyperpolarization of postsynaptic cell membrane

Question 41

electric dipole

Answer 41

a point in space whose electrical propertied can be approximated by assuming that it consists of physically separated positive and negative charges

Question 42

inverse problem

Answer 42

mathematical impossibility of determining the distribution of electrical sources within an object based on the measurement of electric/magnetic fields at the surface of the object

Question 43

evoked potential

Answer 43

field potential that occurs in response to sensory stimulus

Question 44

event-related potentials

Answer 44

(ERPs) small electrical changes in the brain that are associated with sensory or cognitive events

Question 45

ERP component

Answer 45

stereotypic feature of an ERP waveform, such as a peak at a particular latency, that has presumed functional significance

Question 46

forward solution

Answer 46

direct calculation of the electric and magnetic fields that would occur at an array of sensors based on a given distribution of dipoles with known orientations and magnitudes

Question 47

evoked magnetic fields

Answer 47

(EMFs) change in the MEG signal that occurs in response to a particular stimulus - equivalent of evoked or event-related potential in EEG