Neuroscience Methods Flashcards
When looking for a neuroscience method there is often a trade of between what 2 things?
Spatial and temporal resolution
How many layers are there from the cortex to the inner brain?
A 2
B 4
C 6
D 8
C 6
______________ is the technique of segmenting brain into different areas based on appearance
Cytoarchitectonics
When combining neuroanatomy with cytoarchitectonics, different ______ may represent different types of _______
different physical areas reflect different types of cells
Brodmann area 4 (BA4) is known as the _______ ________ cortex. Brodmann areas 1, 2, 3 (BA1, BA2, BA3) make up the __________ cortex. Brodmann are 17 (BA17) is the ______ _______ cortex and Brodmann area 41 (BA41) is the ________ _______ cortex.
BA4 = primary motor cortex
BA1,2,3 = somatosensory cortex
BA17 = primary visual cortex
BA41 = primary auditory cortex
TMS stands for ______ _______ _______
transcranial magnetic stimulation
How does TMS work?
By stimulating one part of the brain we can measure impairment/change in motor/perepetual tasks or direct brain actvity (EEG)
TMS is a safe, non-invasive stimulation which creates a ______ field, which crates a perpendicular ________ field, which causes transcranial magnetic stimulation which _________ neurons
magnetic field crates perpendicular electrical field which causes stimulation and excitation
What are the 4 ways of measuring TMS effects?
1) measuring peripheral responses
2) Measuring impaired/altered perception
3) measuring impaired/altered task performance (motor/perceptual)
4) measuring brain directly using eeg/meg/erp
What are two example studies which used TMS to show the role of certain areas?
Chronometry study by Hamilton et al
Virtual lesion study by Cohen et al
In the Chronometry (and virtual lesion) study, it was found using TMS that the _______ cortex was still used by ________ people to read -_______, suggesting cross-modal plasticity.
Visual cortex still used by blind people to read braille
True are false, virtual lesions are sometimes irreversible and can cause long lasting damage, making them risky.
False - they are fully reversible.
Virtual lesions are more? or less? accurate than true lesions?
More
What are the 6 main advantages of TMS?
+has millisecond temporal resolution
+ can create a cortical map
+risk of neural plasticity is minimal, so can do repeated measures studies
+ can do double disassociation
+ virtual lesions more accurate than true lesions
+ can do larger group studies
What are the 3 main disadvantages of TMS?
- can only study one are at a time
- can only study areas closer to skull (cortical)
- noise from TMS creates issues in auditory stimulation tasks
EEG (electroencephalogram) involves measuring _________ _______ in the brain. It has good ________ resolution but poor _______ resolution.
measuring electrical activity in brain
has good temporal resolution and poor spatial resolution
What is placed on the scalp to measure postsynaptic signals (EEG)?
A Spikes
B Needles
C Electrodes
D Heat sensors
C Electrodes
What are the two main types of EEG oscillations?
Spontaneous oscillations
Event related oscillations
___________ oscillations occur naturally, without any task, and can be used to measure sleep
spontaneous
_______-_______ oscillations are measured in response to a stimulus are task. They can be seen as changes in ________ or amplitude.
Event related - changes in frequency or amplitude
An example of event related oscillations is the suppression of _______ _______ (10hz) oscillations in visual attention tasks, where oscillations on the opposing hemisphere are suppressed.
lateral -occipital-parietal alpha oscillations
ERP’s (Event related potentials) are what?
time locked averages of an EEG response to an event.
By averaging EEG’s across hundred of events you can seperate _____ from _________
ERP’s from spontaneous events.
What are the 3 main types of ERPs?
Exogenous ERPs
Endogenous ERPs
Mesogenous ERPs
Exogenous ERPs are ___________ response of the brain to ________ properties of the stimulus.
automatic responses to physical properties of stimuli
Exogenous ERPs may be useful in ________ _________
biological diagnosis
Endogenous ERPs reflect an interaction between _______ and event, and indicate _________ _______
subject and event
indicate cognitive processes
Endogenous ERPs can be used to look for ___________, __________ and __________
expectation
anticipation
attention
Mesogenous ERPs are a combination of _________ and ____________
endogenous and exogenous
Despite the attempt to localize activity, EEGs are unable to fully localize the ‘________ ________’ as the electrodes never enter __ ______
cannot localize ‘neural generators’ as electrodes never enter brain
Mismatch Negativity (MMN) are EEG responses to ______ _____
deviant tones
MMN can be used in what two types of people?
schizophrenic patients
dyslexic people
Schizophrenic patients can detect differences in ________ of deviant tones, whereas dyslexic people may detect differences in _______ of deviant tones
Schizo - diff in duration
dyslexic - diff in frequency
Classic p300 responses reflect activity in response to _____-_______ _______ stimuli, and has maximum activity in the _______ region whereas novelty p300 activity is response to __________ _______ stimuli and has maximum activity in the ________ region
classic p300 = expected task relevant oddball stimuli, in parietal region
novelty p300 = unexpected deviant stimuli, in frontal region
Schizophrenic patients are found to have a reduced ______ which may suggest impairments in _______ ________
schizo - reduced p300 = impairments in sustaining attention
Endogenous n400 responses occur when reading __________ sentences
semantically incongruent sentences
What are the 3 examples of Endogenous responses?
N400
Readiness potential/movement related potential
contingent negative variation
MEG stands for
magneto-encephalography
MEG as a technique has better _______ resolution than EEG/ERP, whilst still having good _________ resolution, however it requires _____ ______ environments
better spatial resolution whilst maintaining temporal resolution, requires low noise environment
What are the 4 main goals of structural MRI?
to study anatomy
to look for brain abnormalities
to show development
to show neural plasticity
MRI stands for _______ _______ ___________,
and CT stands for ________ __________
MRI = Magnetic resonance imaging
CT = computed topography
Which statement is false regarding STRUCTURAL MRI?
A It relies on contrast between different types of matter
B It is a non-invasive method
C It can help detect brain abnormalities
D It can help localize function by showing response in tasks
D Is false, this is only fMRI
When the subject is outside the magnetic field, the abundant protons are _____________ orientated, however when the subject enters the magnetic field, the protons become ___________ to the external magnetic field.
Outside = randomly orientated
inside = aligned to external magnetic field
In the MRI, once a brief radiofrequency pulse is emitted, what happens to the protons ?
A they become aligned with the magnetic field
B they become randomly orientated
C they go perpendicular to the magnetic field
D Nothing happens
C they become perpendicular
If the protons have a net magnetization of 100%, what is their orientation to the magnetic field
A Perpendicular to magnetic field
B Aligned to magnetic field
C Randomly orientated
D We cannot know the orientation based on net magnetization alone
B = Aligned
What measurement forms the basis of MRI contrast, and how does it work?
spin-lattice relaxation times, which is the time taken for protons of different tissue to re-align with magnetic field.
Spin-lattice relaxation times are also known as ________ signals. Different areas of the brain have different ______ signals. In ________ matter, these signals are the lightest, and are darkest in the _____, with _______ matter in-between. This forms the basis of contrast imaging in the brain.
T1 signals
T1 signals
White matter = lightest
darkest in CSF
grey matter = gray, inbetween
What is the main goal of fMRI?
To link areas with specific processes and create models of brain function
What are the 3 main questions when using fMRI to create data?
1) How to measure neural activity in functional contrasts
2) How to generate measurable functional contrasts in an experiment?
3) How to identify functional contrasts in raw fMRI data?
What are the 2 main premises of how fMRI works?
1) activated areas are ones with blood flow
2) fMRI detects contrast between non activated/ and activated areas (which one uses bllod flow)
the BOLD effect stands for _________ __________ ______ _____________
Blood Oxygen Level Dependent
As blood flow increase, what happens to the capillaries?
more Oxygenated Hemoglobin enters
Oxygenated hemoglobin is _____________ meaning it doesnt affect the magnetic field, whereas deoxygenated hemoglobin is ______________, meaning it makes the magnetic field inhomogeneous.
Oxy Hb = diagmentic, magnetic field unaffected
DeOxy HB = paramagnetic, making field inhomogeneous
fMRI creates T2 signals. In an inhomogensous field (higher deoxy hb) T2 decay is ________ , whereas when there is more OxyHb, T2 decay is _________. The Magnetic rersonance is more intense in areas with _________ T2 decay signals.
SLOWER FASTER
higher deoxy hb, T2 = faster,
higher oxyhb, T2 slower
MR more intnese for slower T2 decay (therefore fMRI detects which areas more oxygneated)
Oxy Hb = diagmentic, magnetic field unaffected
DeOxy HB = paramagnetic, making field inhomogeneous
In an XY signal graph of activity, the X axis represents the ___________, whereas the Y axis represents the _________.
X axis = time course
Y axis = change in activityt
When creating graphs detecting signal activity in fMRI, baseline activity is measured at
A 0%
B 50%
C 100%
D None of the above
C 100%
What statement is the not true of fMRI?
A It has the ability to localise function
B Participants complete tasks whilst under fMRI to link brain areas to processes
C It has very good temporal resolution
D It has very good spatial resolution
C In fact it has a huge temporal delay
What is one issue with fMRI designs that last a long time?
Participants end up fatiguing
There are two types of fMRI experimental design. __________ design uses multiple trials of one type of stimuli, followed by a rest, followed by the next stimuli class. The other type, _____ ______-_______ design, has stimuli occur in mixed sequences or patterns.
Block
rapid event related design
Block designs generally create a _________ signal, are more _______, and have better statistical __________. However, some flaws are that it is susceptible to ________ of upcoming stimulus, and is rather ___________.
+ stronger signal
+more robust
+better statistical power
BUT
- upcoming stimuli predictable
- rather inflexible
Rapid event-related dsigns are more _______ than block designs, and avoid ____________ effects, however they are less __________ to neural events.
+ more flexible
+avoids habituation effects
BUT
- less sensitive to true occurring neural events
What are the 2 main stages of processing fMRI data?
spatial processing
fMRI statistics
In the spatial processing stage, there undergoes a process called __________, where individual images (from one subject) are aligned to one spatial reference volume, creating activation maps. Following this, aligned activation maps with BOLD results are superimposed on a standard resolution image, in a process called ____________. Finally, these superimposed images are aligned on one model brain across all participants to create an average activation image, in a process called _______________.
1) Motion correction
2) Coregistration
3) normalization
The common template often used in the normalization process is called the _________-__________ atlas.
Talairach-Tornoux
How does fMRI statistics work?
it compares the observed time course of rest and task activation, to a predicted time course, to see how closely it is correlated.
What are the 3 main issues with fMRI statistics?
low statistical power due to many voxels
null results hard to interpret
statistical maps depend on amplitude and noise
In Lesion studies. damage of association refers to when _______________________________, whereas damage of dissociation refer to when _____________________________________.
Association damage - one region damaged, but multiple cognitive deficits
Dissociation damage - one region damage, where one task is impaired but another similar task is spared.
Hemispatial neglect occurs when lesions in the _______-__________ junction in the right hemisphere cause deficits in visual __________ for objects/stimuli in the __________ visual field.
lesion to temporo-parietal junction
deficits in attention processing of left visual field
One example of association damage is ____________ syndrome, where various visual processing deficits such as ___________, ___________ _______, and _______ ________ occur.
Balint’s syndrome
visual deficits such as:
simultanagnosia
oculomotor apraxia
optic ataxia
One example of dissociation damage is _______ _____ agnosia. This is when ______________________ (________ stream) is damaged, but ______________ (_______ stream) is still intact.
Visual form agnosia
vision for recognition damaged (ventral stream)
vision for action intact (dorsal stream)
Optic ataxia, which is another dissociation lesion, occurs when _______________ is damaged, but ___________ is intact.
Optic ataxia
vision for action and visually guided action damaged
perception and recognition intact
A complex issue with lesion studies is that lesions amongst many participants may _________, making it difficult to ________ results, however inference from only one participant is _______.
Lesions vary amongst patients, making comparisons hard
However evidence from one patient alone is too weak
