Cognition ch 4

measures of the spatial configuration of different types of tissue in the brain

measures temporary changes in brain physiology associated with cognitive processing

constructed according to the amount of x-ray absorption in different types of tissue

CT scans cannot distinguish between ____ ____ and ____ _____ in the same way as MRI, and it can not be adapted for

characteristics of this type of structural imaging device

strong magnetic field is applied across the part of the body being scanned, this strong external field is applied and a small fraction of hydrogen nuclei in water alight themselves

strength of the magnetic field is measured in units called

designed to measure the moment to moment variable characteristics of the brain that may be associated with changes in cognitive processing

measures the change in blood flow in a region directly, the blood supply to a region increases to supply demand

sensitivity to a concentration of oxygen in the blood

technique for segregating and measuring differences in white matter and gray matter concentration

using MRI to measure white matter connectivity between brain regions

The basic requirement in all functional imaging studies is that

uses a radioactive tracer injected into the bloodstream. the greater the blood flow in a region, the greater the signal emitted by the tracer in that region.

temporal resolution refers to the accuracy with which

the spatial resolution refers to the accuracy with which one can measure

the component that the fMRI is sensitive to is..

blood oxygen level dependent contrast; the signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood

three phases of hemodynamic response function

key advantages of the fMRI

characteristics of PET

characteristics of fMRI

type of experimental design in functional imaging in which activity in a control task is subtracted from activity in an experimental task

effect of one variable on another

ability to identify a set of tasks that has a particular component in common. the problem of interactions can be reduced

measuring associations between brain activity and changes in the variables of interest

measuring the differences in brain activity between two or more conditions

in parametric design a ____ baseline condition is ______ necessary

implies that a region responds to a limited range of stimuli/conditions and that this distinguishes it from the responsiveness of other neighboring regions. not strictly the same as localization

the way in which different regions communicate with each other. the basic approach is to model how activity in different regions is interdependent.

stimuli that belong together in one condition

stimuli from two or more conditions are presented randomly interspersed

advantage of block design

advantages of even related designs over blocked ones

mapping of individual differences in brain anatomy onto a standard template

redistributing brain activity from neighboring voxels to enhance the signal to noise ratio

the most common way of dealing with individual differences is effectively to assume that ..

locations in the brain defined relative to the atlas of Talairach and Tournoux

smoothing _____ some of the raw activation level of a given voxel to neighboring voxels

difficulty in _____ is that the activity in each voxel is not independent, neighboring voxels tend to have similar activity

functional imaging gives us a better idea of which ____ may be sufficient for performing a particular task, but not always which regions are ______ and necessary for performing a task

imaging data imply that a brain region is used in a given task but lesion data suggest that this region is not essential to the task

imaging data imply that a brain region is not used in a given task but lesion data suggest that this region is critical to the task

a progressive loss of information from semantic memory

conceptually based knowledge about the world, including knowledge of people, places, the meaning of objects and words

patients with damage to the left inferior frontal gyrus do not show clinical symptoms of semantic memory impairments because

brain imaging can be used to infer the type of _____ and how the stimulus is _______