Exam #4 Flashcards
The first step to treat epilepsy is to localize _________ _________
Epileptogenic zone
The intracranial EEG (iEEG) surgical treatment proceeds in these two steps
- Electrodes are implanted in the brain
2. Surgery during which the epileptogenic zone is removal
In intracranial EEG (iEEG), it is important to localize the __________ zone and to localize _______ cortex (areas that if removed, will result in a loss of language or other functions)
Epileptogenic; Functional
The main advantages of intracranial EEG (iEEG) are that it can localize generators of ___, and the iEEG signal is much _____ and _______ than when measured on the scalp
ERPs; larger and cleaner
The main disadvantages of intracranial EEG (iEEG) are related to clinical risks such as possibility of ________ or _________.
Infection; Hemmorage
EEG is recorded ______ the brain with Electrocorticography (ECoG) and Stereoelectroencephalography (SEEG)
Inside
Electrocorticography (ECoG) has subdural electrode ______ or strips placed on the exposed surface of the brain below the dura matter after the skull bones are lifted.
Grids
Electrocorticography (ECoG) is preferred for clinical situations in which the epileptogenic zone involves the _______ _______ ________.
Lateral cerebral convexity
Stereoelectroencephalography (SEEG) has _____ ____________ electrodes that are planted into brain tissue at some depth.
Depth multicontact
Stereoelectroencephalography (SEEG) relies on a __ grid system that allows for stereotaxic navigation and _________ __________ through small holes in the skull.
3D; Electrode positioning
Indivuduals who are _________________ become surgery candidates for epilepsy.
Pharmacoresistant
N170 is generated in the ________ gyrus and is larger to _____.
Fusiform; faces
Later deflections of ERP’s (after 300-400ms) are generated in the ________ ________ and _______ _______ cortex to both faces and words (cognitive processing and integration stages).
Anterior temporal; ventral frontal
Spatio-Temporal Model of cognitive processing has early ______ processing at ~___ms in the occipital cortex.
Visual; 100
Spatio-Temporal Model of cognitive processing has ________-________ encoding at ~___ms in the fusiform gyrus.
Material-Specific; 170
Spatio-Temporal Model of cognitive processing has cognitive integration at ~___-___ms in the anterior temporal and prefrontal cortex resulting in ________ ___________
250; 700; Conscious recognition
Magnetoencephalography (MEG) measures magnetic fields genertated by ____________ currents (the same currents that generate EEG)
postsynaptic
The magnetic fields in Magnetoencephalography (MEG) are generated by _________ cells and then conducted to the scalp and measured as EEG
Pyramidal
The Right Thumb Rule: Thumb represents the direction of the ___ _______ and the fingers represent the direction of the ________ _____.
MEG Current; magnetic field
EEG signal is conducted to the _______ of the scalp through the volume of the head but it is attenuated and smeared because of the ____________ differences among tissue types
Surface; conductivity
Magnetic fields are NOT affected by ___________ ______ types, which means they have better _______ resolution.
Intervening tissue; spatial
________ _______ ________ _______ (SQUID) is a special sensor that measures magnetic signal through supercold temperatures
Superconducting Quantum Interference Device
We are surrounded by a lot of ambient electromagnetic noise (lights, cell phones, etc), making it difficult to measure. To protect participants from the environmental interference, the recordings take place in a __________ ________ room
Magnetically shielded
_____-______ _____ (ERFs) are averaged to event markers in a time-locked manner (just like ERPs). The signal is vulnerable to artifacts such as eye blinks, eye movements, motion/muscle artifacts
Event-related fields
The Forward Problem estimates brain sources based on the signal recorded _______ the head, assuming we knew the generators ______ the head.
Outside; inside
The Inverse Problem estimates generators in the brain based on the magnetic fields measured on the _______ of the head.
surface
Anatomically-constrained MEG method records ________ _______ generated by postsynaptic currents, then uses Structural MRI to reconstruct the cortical surface and _______ it for visualization of activity hidden in the _____
magnetic fields; inflate; sulci
A Brain Movie is when you calculate _______ ________ estimates, msec by msec through anatomically-constrained MEG.
cortical activity
M160 (magnetic equivalent of the N170) is largest to _____ ______ (just like in ERPs); it is evoked by stimuli that are face-like and fit a general “faceness” template
inverted faces
M___ it is lateralized to the ____ ______ gyrus except for inverted faces – they evoke activity also in the ____ hemisphere
160; right fusiform; left
(Nuclear) Magnetic Resonance Imaging - (N)MRI has a magnet that is ______ on
Always
fMRI does not measure neural activity directly, but it relies on __________ changes (such as blood flow, also volume and oxygenation rate)
Hemodynamic
The brain uses __% of oxygen and __% of glucose
20; 25
In fMRI ______ resolution is poor; _____ resolution is good
Temporal; Spatial
A ______ is the “volume element” in 3D – it is the basic imaging “unit”. There are more than ___k of them.
Voxel; 140
Hemodynamic Response (HDR) reflects combined changes in ________ blood flow, blood ______, and the rate of oxygen ________
Cerebral; volume; extraction
Ring Activations, or _______ _______ are a common issue in fMRI because a voxel that is at the edge of the brain has some _____ ______ one moment but, after a head movement, it now has no brain tissue (it has air).
head movements; brain tissue
__________ is the claim that firms can figure out “what consumers think and feel about a certain product,” when there is no evidence that activation is related to “liking”
Neuromarketing
Modularity of Cognitive Functions is the idea that cognitive functions are represented by _______ ______ in the brain and that mental processes can be _______.
separate modules; localized
fMRI _____ method is a byproduct of the modularity idea, which means that many/most areas of the brain may be active at the same time, but they will be subtracted out and only the difference will be shown as a very small “_______ area”.
subtraction; activated
The “difference” in the fMRI subtraction method tells us ______ about all of the brain areas that are actually active and contributing to a particular function
Nothing
The Fusiform Face Area (FFA) is the strongest version of the “face-specific” processing module, using a ______ design.
Blocked
There is a dedicated “____ _____” in the fusiform gyrus and that only faces are processed and recognized there (“its own private piece of real estate in the brain”)
Face Module
Representations of faces and objects are _________ and ___________ even in the fusiform gyrus
Distributed; Overlapping
The framework of spatio-temporal stages of processing is where the FFA is sensitive to the visual “faceness” of a stimulus at around ____ ms. However, recognition happens downstream in the ________ _______ and _______ cortices
170; anterior temporal; prefrontal
Temporally-sensitive methods can provide insight into face processing as it unfolds in time – the N170 is an index at a perceptual level but the actual recognition happens at a _____ stage and it involves ______ and ______ cortices
later; temporal; frontal
The ______ effect is a risk in which a person comes too close to a magnet and if they have metal on them, it will fly into the magnet; if implanted in the body, it can be ripped out
Missile
Magnetic fields are measured in _____ units (T). Most human scanners are within the range of ___ T to __ T
Tesla; 1.5; 3
MRI is safe for repeated use because it uses ___-______ ________ and has no known adverse biological effects
non-ionizing radiation
The MRI magnet is surrounded by a strong but invisible magnetic field called the ______ _____
Fringe Field
A potential risks for MRI use is loud noise that may induce nerve or muscle_______ (very rare), tissue ______ of metallic tattoos or metallic make-up
stimulation; heating
An extremely rare potential risk of MRI is ___________ when the magnet has to be shut down and there is a loss of superconductivity when helium is released, displacing oxygen.
Asphyxiation
MRI depends on (______) ______ ________ of the bodily tissue
Nuclear Magnetic Resonance
“______” was dropped from the name because of bad associations. However, the actual phenomenon takes place in the ______ ______ and hence the original name was (N)MRI
Nuclear; Atomic Nucleus
________ is the most abundant element in the universe (the simplest atom with only one proton and one electron)
Hydrogen
The main magnetic field of the scanner is called the ___ (_ ____) field
B0 (B Zero)
When placed in a static magnetic field (B0), hydrogen protons behave like small bar magnets and they tend to get aligned with the B0 field which results in ___ ____________ (the person in the magnet is slightly magnetized)
Net Magnetization
In NMRI, the person’s magnetization is aligned with the direction of the main field B0, it cannot be measured in _________. You have to perturb the system.
Equilibrium
An analogous situation is with measuring someone’s _____. You would need to ____ them off the ground (perturb their standing on the ground in equilibrium) to measure the force that gravity is exerting on them
Weight; Lift
The Radio Frequency (RF) pulse disturbs the _____ ________ with B0. Note that an RF pulse is an ___________ wave.
proton alignment; Electromagnetic
The Radio Frequency (RF) pulse has to be delivered at the ________ frequency (at Larmor frequency) because only then can energy be ________
Resonant; exchanged
Radio Frequency (RF) coils are used both for signal ________ and _______ – they can have different shapes and can accommodate different body parts. In this case, we use _____ _____.
transmitting; receiving; Head Coils
The RF pulse excites the protons and flips the magnetization vectors of the precessing hydrogen protons into a transverse plane where they precess ___ _____ with each other – which means that they are synchronized
In Phase
After the RF pulse is over, the protons _______ and spontaneously get _________ again with the main field (B0).
Dephased; Realigned
T1 relaxation rate differs for different tissue types: the signal is _____ in the fatty tissue (white mater is white on T1 images) and the ______ in the cerebrospinal liquid - it is dark)
higher; lowest
Structural images are important for measurement of the cortical _______, ____, or ______ of a cortical area or a subcortical structure such as the hippocampus or amygdala etc.
thickness; area; volume
EEG has ______ spatial resolution
Poor
fMRI is known as the BOLD (_____ _____ _____ ______) signal
Blood-Oxygen-Level Dependent
When measuring blood flow: fMRI relies on the difference between ________ hemoglobin (diamagnetic) and ___________ hemoglobin (which is paramagnetic)
oxygenated; deoxygenated
During a task, there is a _____ increase in blood flow in the brain (aka the BOLD signal increase)
local
The fMRI activation is defined as the BOLD signal is calculating for each ____ in the brain and presented as statistical (reliability) _______ map.
voxel; activation
