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cognitive neuroscience
seger test 1
151
Psychology
Undergraduate 4
09/16/2010

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Term
advantages of TMS over organic lesion
Definition
no reorganization
can be used to determin timing of cognition
lesion is focal
lesion can be moved within the same participant
can study functional connectivity
Term
advantages of organic lesion over TMS
Definition
subcortical lesions can be studied
lesions can be accurately localized
changes in behavior/cognition are more obvious
Term
event-related potentionals
Definition
measurements of electrical signals generated by the brain through electrodes placed on different points on the scalp
reduced signal to noise ratio
look at timing and amplitute of peaks
Term
representations
Definition
Properties of the world that are manifested in cognitive systems (mental representation) and neural systems (neural representation).
Term
Single-cell recordings (or single-unit recordings)
Definition
Measure the responsiveness of a neuron to a given stimulus (in terms of action potentials per second). Placed in the axon or outside membrane
Term
Multi-cell recordings (or multi-unit recordings)
Definition
The electrical activity (in terms of action potentials per second) of many individually recorded neurons.
Term
rate coding
Definition
The informational content of a neuron may be related to the number of action potentials per second.
Term
temporal coding
Definition
The synchrony of firing may be used by a population of neurons to code the same stimulus or event.
Term
Mental chronometry
Definition
The study of the time course of information processing in the human nervous system. Changes in information processing will manifest in time takes to complete a task.
Term
Mind–body problem
Definition
The problem of how a physical substance (the brain) can give rise to our feelings, thoughts and emotions (our mind).
Term
Additive factors method
Definition
A general method for dividing reaction times into different stages devised by Sternberg.
Term
stages of tasks
Definition
encoding, comparing, decision, responding
Term
exogenous
Definition
related to properties of the stimulus.
tent to be earlier than endogenous
Term
endogenous
Definition
related to properties of the task
Term
Inverse problem
Definition
The difficulty of locating the sources of electrical activity from measurements taken at the scalp (in ERP research).
could calculate backwards from magnitude and location
Term
Dipole modeling
Definition
An attempt to solve the inverse problem in ERP research that involves assuming how many dipoles (regions of electrical activity) contribute to the signal recorded at the scalp.
Term
MEG
Definition
measuring the magnetic field generated from brain currents
unaffected by skull
poor detecting deep dipoles
millisecond temporal resolution
potentially good spatial
expensive
Term
EEG/ERP
Definition
a whole group of neurons have to fire, but nto cancel out each other
affected by the skull
detects all dipoles
sensitive to gyri and sulci activity
millisecodn temporal resolution
poor spatial
cheaper
no vocal
Term
intracellular recording
Definition
electrode in the axon itself
Term
extracellular recording
Definition
outside the membrane
Term
3 tpyes of representations found at the neural level
Definition
local representation (one neuron/grandmother cell)
fully distributed: inofrmation is in all neurons of a given population
sparse distributed representation: distributed representation in which a small portion of the neurons carry information about an event/stimulus
Term
sparse distributed coding
Definition
sparse distributed representation: distributed representation in which a small portion of the neurons carry information about an event/stimulus
high memory cpacity
conserves energy
protects against information loss
allows us to generalize and categorize
Term
erp componenets
Definition
peaks and troughs of the ERP
Term
Associative priming
Definition
Reaction times are faster to a stimulus if that stimulus is preceded by a stimulus of similar meaning (this is also known as semantic priming).
Term
benefits of ERP
Definition
excellent temporal resolution
continous measurement over time
easier to link to neural processes
electrophysiological changes to unattended stimuli
Term
Structural imaging
Definition
Measures of the spatial configuration of different types of tissue in the brain (principally CT and MRI).
based on the fact that tissue has different physical properties
Term
functional imaging
Definition
Measures temporary changes in brain physiology associated with cognitive processing; the most common methods of PET and fMRI are based on a hemodynamic measure.
Term
Computerized tomography scans
Definition
constructed according to the amount of x-ray absorption in different types of tissue
amount of absorption is related to tissue density
cannot distinguish between white and gray matter like mri
Term
MRI
Definition
safe
great spatial
dsicrimitnation in matter
can be adopted in blood oxygenation
Term
functional imaging is designed to
Definition
measure the moment to moment variable characteristics of the brain associated with change sin cogntiive processing
Term
Voxel-based morphometry
Definition
A technique for segregating and measuring differences in white matter and gray matter concentration.
Term
Diffusion tensor imaging (DTI):
Definition
Uses MRI to measure white matter connectivity between brain regions.
Term
BOLD
Definition
Blood oxygen-level-dependent contrast; the signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood.
Term
block design
Definition
Stimuli from a given condition are presented consecutively together.
Term
Event-related design
Definition
Stimuli from two or more conditions are presented randomly or interleaved.
Term
Hemodynamic response function (HRF)
Definition
Changes in the BOLD signal over time.
Term
Pure insertion (also pure deletion)
Definition
The assumption that adding a different component to a task does not change the operation of other components.
Term
interactions
Definition
The effect of one variable upon another.
Term
Functional integration
Definition
The way in which different regions communicate with each other.
Term
efMRI
Definition
Event-related functional magnetic resonance imaging.
Term
Stereotactic normalization
Definition
The mapping of individual differences in brain anatomy onto a standard template.
Term
Smoothing
Definition
Redistributing brain activity from neighboring voxels to enhance the signal-to-noise ratio.
Term
voxel
Definition
A volume-based unit (cf. pixels, which are 2D); in imaging research the brain is divided into many thousands of these.
Term
Talairach coordinates:
Definition
Locations in the brain defined relative to the atlas of Talairach and Tournoux.
Term
inhibition
Definition
A reduction/suppression of the activity of a brain region (or a cognitive process), triggered by activity in another region/process.
Term
excitation
Definition
An increase of the activity of a brain region (or a cognitive process), triggered by activity in another region/process.
Term
activation
Definition
An increase in physiological processing in one condition relative to some other condition(s).
Term
deactivation
Definition
A decrease in physiological processing in one condition relative to some other condition(s).
Term
Aneurysm
Definition
Over-elastic region of artery that is prone to rupture.
Term
Task-demand artefact
Definition
One task is performed worse than another because the task is performed sub-optimally (but not because some aspect of the task is compromised).
Term
Task-resource artefact
Definition
If two tasks share the same neural/cognitive resource but one task uses it more, then damage to this resource will affect one task more than the other.
Term
dysgraphia
Definition
difficulties in spelling and writing
Term
Transparency assumption
Definition
Lesions affect one or more components within the pre-existing cognitive system but do not result in a completely new cognitive system being created.
Term
Neuroconstructivism
Definition
A process of interaction between environment and multiple brain-based constraints that leads to the mature cognitive system emerging out of transformations of earlier ones.
Term
Neural tube
Definition
The embryo’s precursor to the central nervous system, consisting of a set of cells arranged in a hollow cylinder.
Term
Neuroblasts
Definition
Stem cells for neurons.
Term
Radial glial cells
Definition
Support cells that guide neurons from the neural tube to final destination.
Term
Sensitive period
Definition
A time window in which appropriate environmental input is particularly important (but not necessarily essential) for learning to take place.
Term
prepared learning
Definition
The theory that common phobias are biologically determined from evolutionary pressures.
Term
Orofacial dyspraxia
Definition
An impaired ability to perform the coordinated movements that are required for speech.
Term
cortex
Definition
layers on neurons, differr in thickness
Term
sensory cortex
Definition
layer 4
Term
motor cortex
Definition
layer 5 and 6
Term
association cortex
Definition
layers 1-3
Term
columns and layers function
Definition
pass through all layers of cortex
Layer 4: input
Layers 1-3: local processing & Interneurons
Layers 5-6: Output
Term
Approaches to studyingneurotransmitter systems
Definition
Tracer Studies in slices
PET (Positron Emission Tomography)
Pharmaceuticals
Gene studies
Term
interactions between systems
Definition
inhibitation and excitation
different levels: synapses, regions, neuromodulators
methods don't always show this
Term
three components of methods/techniques
Definition
temporal
spatial
invsiveiness
Term
electromagnetic methods
Definition
single cell recordings
eeg/erp
MEG
Term
imaging methods
Definition
functional and anatomical imaging
Term
lesion methods
Definition
human lesion, animal, teporary, and pharmacological
Term
single unit recordings
Definition
measures action potential
good spatial and temporal localization
not for high processing
can't generalize
not on humans, no language
Term
single unit recordings design issues
Definition
species
task appropriate
individual cells as subjects
Term
direct electrical recording in humans
Definition
pre/during surgery
why? Eplypsy and tumors
implanting electrodes
Term
EEG
Definition
sensitive to neural activity in the dendrites
neural bassis is of electric dipoles in axons
Term
eegs are good for
Definition
overall pictures of brain activity
temporal localization
mental states
Term
eeg limitations
Definition
bad spatial localization
data is noisy
Term
p3 or p300
Definition
Component sensitive to novelty
Term
N400
Definition
Component sensitive to semantic errors
Term
ERN
Definition
Error Related Negativity
Term
N170
Definition
Component sensitive to faces
Term
MMN
Definition
Mistmatch negativity
Term
interpreting ERP results
Definition
Mental chronometry: when are two processes diverge in time?
different timing = different processes
scalp topography
Term
Interpretation traps in EEG
Definition
Negative =/= inhibition; positive =/= excitation
All pyramidal cells are excitatory
Amplitude: Higher doesn’t always mean more activity.
Depends on baseline -- which is arbitrary
Components don’t correspond to single brain regions.
Most are a sum of contributions from many regions
Scalp location =/= brain location.
Term
Functional Brain Imaging: advatage and disadvantages
Definition
Advantage of both methods: Good spatial
Disadvantages of both methods: Poor temporal resolution, but FMRI is better than PET
Term
brain activity correlates with
Definition
blood flow
Term
why does a neuron needs blood?
Definition
dendrites need blood to focus and synaptic inputs and gated channels
Term
why is functional brain imaging poor?
Definition
blood flow is slow
Term
block fMRI studies
Definition
group events
Term
Preprocessing data fMRI (4) and what they do
Definition
Motion correction: Mathematical corrections of movement
Smoothing: removing noise for statistical analysis also helps for looking across people by allowing us to overlap
Normalization to template image: Morph subjects brain to match template
Averaging across subjects: average data to smooth out bumps in recording
Term
Cognitive subtraction
Definition
subtracted control activated areas or previous task
Term
fmri and brain area necessity
Definition
cannot show if needed for a task
have to interrupt area to check performance'
Term
When is fMRI appropriate?
Definition
When your experimental question is really about the brain.
When you can design appropriate tasks that can be done in the scanner, and will isolate your process of interest.
If a behavioral study will answer your question, then no need for fMRI.
Don’t expect fMRI to provide the final answer; fMRI is best for hypothesis formation and development. Confirm results with another methodology
Term
why voxel?
Definition
look at smaller scale within regions, as activity is distributed across regions
Term
Functional Connectivity
Definition
fMRI not so good at indicating whether and how active regions interact
Seed region based models
Model Testing Methods
Term
Seed region based models
Definition
Start with one area of the brain (seed region)
See what interacts with it.
Exploratory method
Term
Model Testing Methods
Definition
Test a theory of how regions interact.
Mediation Effect Mapping
Reappraisal: think of a situation in other ways, not bad
Term
PET Imaging of Neurotransmitter systems
Definition
Absolute measures of brain activity
Neurotransmitter systems
Term
Anatomical Imaging
Definition
Planes of section
CT
MRI
Comparing groups using voxel based morphometry
Term
PET can give an absolute measure of neural activity
Definition
Compare disease to controls
Rack time course of disease
FDG-PET= flurodeoxyglucose
Track changes in blood flow by tracking glucose
Term
Using PET to image NTs in vivo
Definition
Classic PET measures blood flow by adding the radioactive tag to water, glucose, or oxygen.
• Can also add the tag to other ligands
Can look at baseline binding (chemical anatomy)
Or at changes due to tasks (functional chemical anatomy)
Term
Performing MR anatomy studies
Definition
Voxel Based Morphometry (VBM)
Multiple measures of gray matter: volume and morphology
can measure normal differences, not abnormalities
Term
applications MR anatomy studies
Definition
“Normal” Individual differences
Development
Clinical studies
Term
White Matter Tract methods
Definition
Tract tracing
Diffusion Tensor Imaging
Term
retrograde labeling
Definition
Label that spreads from axon terminal to cell body / dendrites.
Term
anterograde labeling
Definition
label that spreads from cell body to axon and axon terminal.
Term
Diffusion Tensor Imaging (DTI)
Definition
Noninvasive study of white matter tracts
Measures direction of water flow.
Term
issues diffusion tensor imaging
Definition
Uses standard MRI setup.
Often combined with MRI and fMRI
Doesn’t show white matter
breaks in white matter affect cognition as it the disrupted connections
Term
Permanent lesions due to accidents or disease
Definition
Brain tumor
Cerebrovascular disorders (stroke)
Traumatic brain injury (TBI)
Infection
Degenerative diseases
Anoxia or toxin exposure
Term
Adult versus developmental studies (lesions)
Definition
Changes and ability to overcome
Term
design issues in brain damage studies
Definition
Case studies vs. group studies
Which disease to study?
Appropriate control groups
Single and double dissociations
Term
Associating location of brain damage with cognitive function
Definition
Descriptive methods
Overlap methods
Voxel based Lesion Symptom Mapping
Term
lesions to study
Definition
cognitive differentation (location irrelevant)
brain localization anatomical region and larger scale systems
Term
issues with lesions
Definition
white matter damage
plasticity
Term
lesions location and function (group sizes)
Definition
description of lesions best for case studies or small groups
overlap method small to medium
voxel mapping, larg group
Term
Voxel based lesion symptom mapping (VLSM)
Definition
lesion overlap
lesions locations correlated with performance
Term
lesion overlap
Definition
See where the damage happens spatially
Term
animal Permanent lesions
Definition
Aspiration
Transection
Chemical
Term
transection
Definition
(cut through white matter tracts)
Term
aspiration
Definition
remove gray matter
Term
Two main maturational forces:
Definition
Increased Mylenization
Synapse pruning
Term
Functional Consequences of maturation
Definition
Increased interconnectivity between brain regions (related to Mylenization)
Increased specificity of cortical representations
Term
order of progression of mylenization
Definition
1. Sensory and motor areas first
2. Parietal lobes and inferior temporal lobes later
3. Frontal lobes (tan) and corpus callosum last
Term
Synapse Generation and Pruning
Definition
Synapse density in the visual and frontal cortex
Increases in dendrites and synapses across development
And then they are pruned down.
Term
Gray matter development
Definition
Gray matter increase and decreases across childhood/adolescence
Need to be pruned back if they are being used
Front cortex is the last in maturing
Term
Functional interconnections across age
Definition
Better integration and working together across age
Term
Physical brain changes with aging
Definition
loss of myelin
synaptic degeneration
blood flow reduction, particularly anterior
similar to childhood
Term
Interpretation Issues in Developmental Studies
Definition
anatomical imaging (volume isn't meaningful)
functional imaging patterns (decreased activity doesn't mean worse)
different pattern of activity
Term
Traumatic brain injury X age
Definition
Complex interaction of age and recovery
phases in development that affects the relationship
Term
Factors contributing to functional impairment
Definition
Highly specialized brain regions
Competitive processes across brain regions
"Teacher” and “student” relationships between regions
Term
genes are
Definition
code for proteins
generalists (used many areas)
switchable (on or off)< master genes
Term
genes are not
Definition
Code for traits or behaviors
Blueprints/0ne-2-one
insensitive to the environment
active only before birth
Term
How genes guide development
Definition
code proteins necessary for the brain
when they should be developed
brain builds self from guidelines
adjust for environment from genes switching on or off
Term
Single nucleotide polymorphism
Definition
Small differences in DNA can lead to small differences in proteins.
amino acids
Term
DA neurotransmission genes
Definition
receptors
reuptake
synthesis enzymes
degradation enzymes
Term
degradation enzymes
Definition
mao
comt
Term
issues in performing studies of genetic developmental disorders
Definition
design issue: what is a comparision group?
interpretation issue: broad function of genes and developmental trajectory
Term
Amgydala changes associated with
Definition
hypersociability
Term
Parietal lobe changes associated with
Definition
spatial impairments
Term
Adult phenotype may not reflect infant/child
Definition
Can’t see nearly the difference as you see when they are older
Term
design for PET
Definition
block design ONLY
Term
Hrf has three phases
Definition
initial dip
overcompensation
undershoot
Term
parametric design
Definition
the variable of interest is treated as a continuous dimension rather than a categorical distinction
Term
block design benefit
Definition
more power, detect small effects
Term
3 assumptions in lesion studies
Definition
factionation assumption
transparency assumption
universality assumption
Term
fractionation assumption
Definition
damage to brain can produce sleective cognitive lesions
Term
universality assumption
Definition
the universality assumption is that all congitive systems are basically identical
Term
odema
Definition
a swelling of the brain following injury
Term
grouping of lesion patients
Definition
syndrome
cognitive symptom
anatomical lesion
Term
diaschisis
Definition
A discrete brain lesion can disrupt the functioning of distant brain regions that are structurally intact
Term
Dual-task interference
Definition
If there is a decrement in performance associated with doing two things at once, it suggests that these two tasks share cognitive processes.
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