MT 1 Flashcards

Question

how can the temporal lobe be split up

Answer 1

- superior temporal gyrus - middle temporal gyrus - inferior temporal gyrus 1.2 slide 20

Answer 2

- amygdala - hippocampus - thalamus - hypothalamus - cingulate gyrus - basal ganglia

Answer 3

anterior -- front of the brain posterior -- back of the brain

Answer 4

parieto-occipital sulcus

Answer 5

maxillary, manibular, and opthalmic branch

Answer 6

19% neurons to 82% mass **more mass per neuron

Answer 7

80% neurons to 10% mass **more neurons per mass

Answer 8

1% neurons to 8% mass **more mass per neuron but smaller overall

Answer 9

proposed the neuron doctrine

Answer 10

The concept that the nervous system is made up of discrete individual cells, neurons. Neurons may touch one another, but they do not fuse.

Answer 11

known for mapping the cerebral cortex and defining 52 distinct regions, known as Brodmann areas, based on their cytoarchitectonic characteristics.

Answer 12

the arrangement of cells in a tissue, especially in specific areas of the cerebral cortex characterized by the arrangement of their cells and each associated with particular functions. ex. neuron size, shape, packing density, etc.

Answer 13

regions of the cerebral cortex that are defined by their cellular structure and organization. These regions, or Brodmann areas, correspond with diverse functions including sensation, motor control, and cognition.

Answer 14

primary motor cortex

Answer 15

primary somatosensory cortex

Answer 16

wernicke's area

Answer 17

broca's area

Answer 18

primary auditory cortex

Answer 19

primary visual cortex

Answer 20

brodmann area 17, aka primary visual cortex, receives principal afferents from the lateral geniculate nucleus of the thalamus

Answer 21

1.2 slide 44

Answer 22

- unipolar - bipolar - pseudounipolar -- (classified under unipolar) - multipolar

Answer 23

1.2 slide 45

Answer 24

1.2 slide 45

Answer 25

1.2 slide 45

Answer 26

1.2 slide 45

Answer 27

1.2 slide 45

Answer 28

1.2 slide 47

Answer 29

1.2 slide 47

Answer 30

- glutamate - gaba - dopamine - serotonin - opiods

Answer 31

most neurons contain a single type of NT (the chemical contained in the presynaptic vesicles); some neurons have co-transmitters (more than one). recepters vary in terms of transmitter affinity -- a single neuron may have multipke receptor types.

Answer 32

axon hillock (depolarization) travels down the axon

Answer 33

electrical and chemical

Answer 34

Electrical synapses: - Direct connection between neurons via gap junctions, allowing for almost instantaneous signal transmission. - Bidirectional signal transmission. - Usually found in situations requiring rapid response, like in certain reflexes. Chemical synapses: - Signal transmission occurs through the release of neurotransmitters from the presynaptic neuron, which bind to receptors on the postsynaptic neuron. - More common than electrical synapses. - Unidirectional signal transmission. 1.2 slide 48

Answer 35

1. Cytoarchitecture - cell histology (density/cell type, etc) (structure) 2. Sulci/Gyri - bumps and grooves of brain (function) 3. Lobes - large scale anatomy/well defined sulci (structure) 4. Function - localize by studying function in some way (we will learn more about later in the class) (function)

Answer 36

a study design that randomly allocates participants to a specific condition. For example, participants can be assigned to an experimental group to compare to a control group.

Answer 37

as the study is conducted, any relationship seen between variables can be attributed to the intervention (or the outcome variable being studied). Additionally, this study design is considered to be less biased, compared to other designs.

Answer 38

it is not always possible and can be expensive or difficult to carry out.

Answer 39

is retrospective and compares individuals with a specific condition or case to individuals without it (or the controls). These individuals are matched with controls based on several different factors, such as age and sex.

Answer 40

sometimes this is the only ethical way to test certain questions, which can be especially valuable for individuals with extremely rare conditions.

Answer 41

it can be hard to draw strong conclusions because there are many factors that can cause differences. It is also difficult to control for all confounds. These cons may be associated with a smaller sample size.

Answer 42

reports on one person (or a small group of people) to explore a rare or unique phenomenon. These designs may look at medical history, treatment plans, symptoms, and other related factors.

Answer 43

can provide a lot of detail on the medical history of the patient of interest and can help give more insight into specific conditions

Answer 44

they may not be generalizable to other cases

Answer 45

observational study that follows a group of individuals over time to assess the relationship between exposures and outcomes. It can either be prospective by tracking participants forward in time or retrospective by using past records to analyze outcomes.

Answer 46

it can sometimes be the only ethical way to test a certain question.

Answer 47

there may be differences besides those of interest that affect the results. Additionally, follow-up after long periods of time may not be feasible.

Answer 48

collects data at a single point in time.

Answer 49

fairly easy to implement. It is also typically more cost-effective, compared to other studies.

Answer 50

may be less accurate, especially with respect to past data. It is also harder to control across groups.

Answer 51

when individuals are unaware of the manipulation of a variable.

Answer 52

only the participants are unaware of group allocation.

Answer 53

both participants and researchers are unaware of group allocation.

Answer 54

the phenomenon where participants experience a perceived or actual improvement in their condition due to their belief in the efficacy of a treatment, even when the treatment is inactive. Thus, a placebo matches the manipulated variable to a null manipulation, such as a sugar pill.

Answer 55

- had epilepsy - Unable to learn any new information after surgery - Able to remember all memories before his surgery - Intact short-term/working memory (intact prefrontal cortex) - Able to learn new procedural skills (intact basal ganglia) - No change in his intelligence, language, perceptual abilities - No change in his personality **demonstrated that the hippocampus is crucial for forming new memories

Answer 56

B) Can help guide searching for other related articles.

Answer 57

D) Depends on the journal

Answer 58

D) Administer the rating scales to the patients.

Answer 59

1. mental status 2. cranial nerves 3. motor system 4. reflexes 5. sensory system 6. coordination / balance 7. gait

Answer 60

mental status exam - normal x 4 (1. person, 2. place, 3. time, 4. situation) - if concerns, do MMSE (30/30) - memory -- ask them to remember 3 things and test recall then and five minutes later - language (looking for broca's / wernicke's aphasia)

Answer 61

A Mini-Mental State Examination (MMSE) is a test of ~11 questions. It's used by to check for cognitive impairment

Answer 62

sometimes referred to as "extinction" or "inattention" a neurological condition where a person, usually following brain damage to one hemisphere, becomes unaware of stimuli on the opposite side of their body or environment, essentially ignoring that side of space, even though they may not have any sensory loss there; it's primarily associated with damage to the right parietal lobe, causing neglect on the left side. remember the clock that finished halfway in the circle 2.2 slide 9

Answer 63

difficulty speaking and forming words, even though they can understand it

Answer 64

difficulty understanding language, even though the person may speak fluently but with nonsensical content

Answer 65

test each nerve individually

Answer 66

olfactory nerve - very frequently damaged due to many spiny things in the front of the head by the nerve ex. traumatic anosmia -- head injury causing the brain to hit the front of the skull (causing loss of sense of smell) - parkinson's presents first with loss of sense of smell - people typically say that they can't smell - assessed by using vials of scent

Answer 67

optic nerve -- visual info - snellen chart -- typical eye exam chart with the letters

Answer 68

a stroke that occurs in the occipital lobe of the brain, which is responsible for processing visual information

Answer 69

a visual field defect that affects the same side of both eyes. It can cause difficulty reading, seeing obstacles, and other visual impairments. can see things on right side but not left

Answer 70

E) A and D

Answer 71

often benign, but they cause problems because they are push on the brain, putting pressure on other things (puts pressure on optic chiasm)

Answer 72

A stroke on one side of the brain can cause vision loss in the opposite side of the visual field in both eyes. ex. homonymous hemianopsia

Answer 73

test eyes separately to look for deficits in the visual field. anything that is eye specific = before the optic chiasm anything that is in both eyes, but related to the periphery = at the optic chiasm anything that is in both eyes and contralateral = after the optic chiasm

Answer 74

2.2 slide 18

Answer 75

pupillary response

Answer 76

shine light in one eye and observe contraction in BOTH eyes

Answer 77

oculomotor, trochlear, and abducens - look at eye movements -- hold head stable and test movement in all directions

Answer 78

up, down, and in toward the nose

Answer 79

lateral movements away from the nose

Answer 80

down toward the nose

Answer 81

trigeminal -- motor and sensory components (face sensations and muscles for biting and chewing) - sensory - touch areas lightly with patient's eyes closed - motor have patient grind and clench teeth and feel muscle

Answer 82

facial nerve look at facial expression movements

Answer 83

movement of face on one side of the face - can occur due to neural damage or can temporarily be there from viral infections

Answer 84

cortical (stroke): - forehead spared (there are still wrinkles on both sides of the forehead) - indicates upper motor neuron lesion cranial nerve (bell's palsey): - forehead weak (wrinkles are not continuous because one half has no sensation) - indicates lower motor neuron lesion

Answer 85

2.2 slide 24

Answer 86

lower motor neurons

Answer 87

upper = prior to braintsem lower = other side of the medulla to the spinal cord

Answer 88

2.2 slide 25

Answer 89

auditory nerve rub fingers together near patients ears individually, and ask when they can hear it. if deficit is noted, can also test hearing loss with tests like weber test

Answer 90

*is interesting because in each ear, there is coverage from both hemispheres. for example, stroke doesn't often show hearing damage unless it happened bilaterally

Answer 91

place vibrating tuning fork on top of head normal --> equally loud on both sides obstruction (ex. wax) --> louder on side WITH hearing impairment (bone conducts sound louder than air / less competing sound) sensorineural --> louder on side without impairment

Answer 92

glossopharyngeal and vagus - listen to the voice of patient (sometimes its hoarse) - have patient swallow and cough

Answer 93

accessory - shrug and turn head - rarely abnormal **trapezius and sternocleidomastoid

Answer 94

hypoglossal - check for deviations and deflections in tongue - tongue points to lesion

Answer 95

motor system inspect muscles for appearance (atrophy, fasciculations), palpate for tone (spasticity, flaccidity, rigidity), and test muscle strength by asking the patient to perform specific movements against resistance, while observing for any involuntary movements, coordination issues, and range of motion limitations, comparing each side of the body for symmetry

Answer 96

test reflexes sensory neurons detect the stimulus and send a signal to the spinal cord, which then sends a signal back to motor neurons to produce the response interneurons are involved in many reflexes, particularly in those that require coordination between sensory and motor neurons

Answer 97

indicates cortico spinal tract damage toes down = normal big toe up (dorsiflexion) = babinski sign indicator of upper motor neuron damage

Answer 98

When the tendon is tapped (for example, the patellar tendon below the knee), the stretch activates sensory neurons that send a signal to the spinal cord. The signal is processed and relayed to motor neurons via interneurons, which cause the muscle to contract lower motor neuron/muscle/sensory damage = depressed reflexes upper motor neuron damage = exaggerated reflexes

Answer 99

evaluate reflexes

Answer 100

coordination / balance / gait - reach to target, if they can land there it indicates cerebellum control - finger to nose / heel to shin tests - rapid alternating movements --> ex. rapidly tapping their fingers on a surface to look dor irregularities in movement romberg test --> patient stands with their eyes closed. if they sway or fall, it indicates they were relying on visual feedback to keep them standing.

Answer 101

a condition that makes it difficult to control the speed, distance, and range of physical movement (a type of ataxia)

Answer 102

the way a person walks or runs

Answer 103

a walking pattern that's characterized by short, shuffling steps, and a general slowness of movement

Answer 104

a condition that causes a person to lose their balance and lean backward -- having patient stand then pulling them off balance to see if they fall

Answer 105

E) All of the above

Answer 106

drilling a hole in the skull

Answer 107

d) qualities of a person can be determined by the bumps on their skull

Answer 108

c) the sylvian fissure

Answer 109

c) the cerebellum contains the greatest percentage of neurons in the brain, but does not have the greatest mass

Answer 110

d) randomized double blind control

Answer 111

confrontation test --> evaluates visual field test for Babinski sign --> function of corticospinal tract Weber test --> hearing (nerve 8 - vestibulocochlear) the UPDRS --> unified parkinson's disease rating scale -- used to asses motor and non motor deficits of parkinsons disease answer: a) confrontation test

Answer 112

d) both A and C

Answer 113

answer: UPDRS --> unified parkinsons disease rating scale -- used to assess motor and non motor deficits of parkinsons disease MMSE --> mini mental state exam -- assess cognitive function FMA --> fugl-meyer assessment -- evaluate motor recovery after a stroke face arm speech test --> used to screen for stroke by assessing facial drooping, arm weakness, and speech difficulties

Answer 114

E) B and C

Answer 115

changes in electrical activity. specifcally, they measure synaptic currents because they last longer, while action potentials are much more brief. ex. electrode measuring voltage of a neuron

Answer 116

are the electrical currents that flow across the synapse when neurotransmitters are released from a presynaptic neuron and bind to receptors on the postsynaptic neuron. These currents result from the movement of ions through ion channels in the postsynaptic membrane, leading to changes in the postsynaptic cell's membrane potential.

Answer 117

1. single units 2. local field potential (LFPs) 3. intracranial electroencephalography (iEEG) 4. EEG electrode

Answer 118

~1 micrometer

Answer 119

you can resolve action potentials from one or a small number of neurons (this is the only scale that we're studying that can do this). this scale is not used clinically because over time (ex. looking at data the next day) you're not entirely sure if you're still measuring the same neuron. it's invasive and is done by carefully implanting a very fine, micro-sized electrode, typically made of glass, into the brain tissue. skull and cortex are pierced

Answer 120

involves a larger electrode so you detect hyperpolarization / depolarization currents (synaptic currents). electrodes implanted in the brain to measure the summed electrical activity of neurons within a localized region this is an invasive procedure. it's done by piercing skull and cortex

Answer 121

placed on cortex. its still invasive but you're not penetrating the brain.

Answer 122

same size as iEEG, but signal is more diffuse due to more stuff that it has to pass through. Non-invasive; you can put it on your head and it will pass through hair and skull.

Answer 123

(best): single unit 2. LFPs 3. iEEG (worst): EEG electrode

Answer 124

the level of detail captured in an image, essentially measuring how small an object can be and still be distinguished within an image. ex. EEG electrode gives you more of a picture of the brain; but the resolution is worse.

Answer 125

all have good temporal resolution

Answer 126

all of these are extracellular recordings --> an electrode placed somewhere outside of the cell.

Answer 127

Hans Berger

Answer 128

C) Summed synaptic potentials from large populations of neurons

Answer 129

- Sufficient number of neurons (1000-10,000+) with proper orientation (parallel). - Active together - With electric fields that sum, not cancel --> electrical activity generated by neurons must align in such a way that their individual electric fields add up to produce a measurable signal, rather than cancelling each other out due to opposing directions.

Answer 130

1. tonic 2. clonic 3. postictal stupor

Answer 131

- body rigid - arched position - arhythmic, high amplitude spiking on EEG - EEG shows an increase in fast, low-voltage wave activity in both hemispheres of the brain

Answer 132

- convulsions - EEG oscillates (periodic spikes). high-amplitude spike-and-slow-wave activity. This means that there are bursts of spikes followed by slow waves.

Answer 133

- unresponsive or confused - very small EEG signal

Answer 134

- rhythmic, marked activity in EEG with a frequency around 3 Hz - hallmarked by staring off in space, much more subtle - EEG shows symmetrical, generalized "spike and wave" discharges slide 21

Answer 135

any part of the brain that's a little extra 'ticklish' can trigger a seizure --> ex. flashing lights or getting a seizure listening to a led zepplin song --> its a specific pathway of activity

Answer 136

a seizure that starts in both sides of the brain at the same time. They can cause loss of consciousness, abnormal movements, and other symptoms - Absence - Tonic clonic

Answer 137

(one side of the brain) - Simple (ex. sensation, smell, sound) - Complex (ex. Person confused, dazed, unresponsive)

Answer 138

Raw EEG data can be used to determine stages of sleep, and this can be used to help diagnose sleep disorders

Answer 139

a pattern of low-amplitude, high-frequency brain waves called "beta waves" primarily seen in the frontal regions, with occasional "alpha waves" (slightly slower, larger amplitude waves) present in the posterior regions of the brain (low signals overall) slide

Answer 140

a mixed pattern of alpha waves (typical of wakefulness) transitioning to theta waves, with the presence of "vertex sharp transients" (brief, sharp waves) and slow rolling eye movements

Answer 141

the presence of "sleep spindles" and "K-complexes", which appear as distinct bursts of high-frequency activity amidst a background of lower frequency waves, essentially signifying a pattern of rapid, rhythmic brain wave activity interspersed with larger, slower waves

Answer 142

large, high-amplitude waves called "delta waves" with a low frequency

Answer 143

a pattern of low amplitude, mixed frequency brain waves that are quite similar to the brain activity seen when awake, often described as "desynchronized" activity, meaning it has a mix of different frequencies with no dominant pattern

Answer 144

it would typically show low-voltage, irregular brainwave activity with a mix of slow waves (delta and theta) and sometimes some faster activity (alpha and beta), often with decreased reactivity to sensory stimuli, indicating a diminished level of cortical engagement despite the outward appearance of wakefulness

Answer 145

a pattern of significantly slowed brainwave activity, primarily consisting of low-frequency theta and delta waves, with occasional bursts of higher frequency activity like alpha waves, indicating some level of cortical activity, but with a diminished reactivity to stimuli compared to a healthy individual (overall higher signals compared to eyes open)

Answer 146

significantly slowed brain activity, with a pattern of low-voltage, irregular waves, often lacking the normal variations in brain wave frequencies seen in a conscious person

Answer 147

a pattern of significantly reduced brain activity, characterized by slow, high-amplitude waves, often with a dominant "delta" wave pattern, indicating a deep level of unconsciousness (sometimes referred to as burst suppression)

Answer 148

a "flat line" or "isoelectric" meaning there is essentially no detectable brain activity, showing a complete absence of electrical waves

Answer 149

C) They are having an absence seizure

Answer 150

an electrical potential recorded from the nervous system of a human or animal following presentation of a stimulus, as distinct from spontaneous potentials as detected by EEG

Answer 151

to get rid of background noise -- the more you average, the more confidence you have that the signal you are seeing is the right one to focus on

Answer 152

a painless test that measures how well the auditory nerve and brainstem respond to sound

Answer 153

Newborn hearing test Electrodes are placed on the baby's head and neck, and soft headphones are placed over the ears. Clicking sounds are played and the test measures the brain's response. First 3 waves from 8th cranial nerve (vestibulocochlear) and lower brain stem regions Waves 4 and 5 from upper brain stem

Answer 154

a type of brain-computer interface that allows users to communicate by selecting characters on a screen by focusing their attention on the desired character which triggers a specific brainwave called the P300

Answer 155

Any signal can be decomposed into sine waves of different frequencies. This is a good way to analyze brain data, because brain activity naturally ‘oscillates’.

Answer 156

During rest, a rhythm at 8-12 Hz or so can be seen which is reduced with movement

Answer 157

Certain behaviors are associated with changes in certain frequencies Similar changes in this frequency range are present when movements are imagined

Answer 158

a mathematical method that predicts the value of a measurement based on known physical parameters The Forward problem is hard, but possible like asking what -3+4+2+4 equals think brain to head

Answer 159

The Inverse problem has an infinite number of solutions - like asking what numbers sum to 7 think head to brain

Answer 160

- the "forward problem" refers to calculating the electrical potential on the scalp based on known brain activity sources (you know what you need to do to figure out an answer) - the "inverse problem" is the process of determining the location of those brain activity sources by analyzing the measured EEG signals at the scalp (you have the answer, but need to know how) - essentially working backwards from the recorded data to find the underlying neural sources responsible for the signal

Answer 161

This means that, although EEG has good temporal resolution (i.e. can detect brain changes with very precise timing, It has poor spatial resolution - i.e. telling where brain activity is coming from is challenging

Answer 162

E) All of the above

Answer 163

a type of epilepsy where seizures are difficult to control with medication Surgery can be considered, but a source needs to be determined

Answer 164

High-frequency activity (>70 Hz).

Answer 165

It tracks local neural activity accurately.

Answer 166

strength: - high temporal resolution - non-invasive - affordable - translatable weakness: - low spatial resolution - can't record action potential

Answer 167

vision impacted in one eye

Answer 168

vision impacted in both eyes

Answer 169

neurological perspective: standing behind a patient (ex. your right is the patient's right) radiological perspective: standing at the patients feet (ex. your right is the patients left)

Answer 170

computed tomography

Answer 171

- glorified x-ray that makes a 3D image - x-ray rotates around a patient - CT is sensitive to tissue type differences in the irradiated region because x-rays are blunted differently as they pass through different tissues - bone blocks a lot, grey matter some, and fluid less - multiple snapshots are taken using detectors around the circumference of the scammer and merged together using a computer

Answer 172

above the dura, so it pushes on the brain a bit more. also has a lenticular shape (like a balloon filled with fluid) pushing against the dura from the outside. doesn't spread out as much because of how tightly attached the dura is to the brain

Answer 173

a non-invasive imaging test that uses X-rays and a contrast dye (typically an iodine rich contrast agent) injected into the body to create detailed pictures of blood vessels and tissues you may be able to see aneurysms

Answer 174

strong typically between 1.5-10.5 tesla (earth's magnetic field is 25-64 microT) -- so MRI is stronger

Answer 175

rapidly demagnitizes by funneling helium out through a vent

Answer 176

ferromagnetic metal (sticks to the fridge)

Answer 177

it can heat up a little

Answer 178

A higher T MRI, like a 3T MRI, is used when you need significantly improved image quality and detail compared to a lower T MRI (like 1.5T) due to its stronger magnetic field, allowing for better visualization of smaller structures and subtle abnormalities, particularly in areas like the brain, spine, and small joints, which can be crucial for accurate diagnosis in certain conditions; this is especially beneficial for neurologic imaging, musculoskeletal scans, and when high spatial resolution is required. however, higher T is higher cost and some patients may not be able to tolerate the high field. also, you have more susceptibility to artifacts

Answer 179

- in your body there are hydrogen protons that are spinning around that are typically oriented differently - when you enter the magnetic field, the hydrogens all align and their spin becomes parallel. - MRI sends radiofrequency pulses to excite these protons, which causes protons to go out of alignment, so we can measure properties of how these protons realign. - As they realign, energy is released and you can measure different properties of how that release happens - Different molecules and tissues have different relaxation times and spins.

Answer 180

Think fat and anatomy Measures the time it takes for protons in the tissue to return to their original alignment after an RF pulse. Tissues with high fat content (e.g., white matter) have short T1 relaxation times, making them appear bright. ex. assessing anatomy or a tumor

Answer 181

think fluid and inflammation Measures the time it takes for protons to lose their alignment due to interactions with their surroundings. Tissues with high water content (e.g., CSF) have long T2 relaxation times, making them appear bright. better at detecting edema, inflammation, and stroke

Answer 182

T1 -- white cortex; dark fluid T2 -- dark cortex; white fluid

Answer 183

fluid attenuated inversion recovery uses a specific pulse sequence to suppress the signal from cerebrospinal fluid (CSF), allowing for better visualization of surrounding brain tissues, particularly lesions near the ventricles looks similar to T1 weighted but it is a bit darker

Answer 184

light gray

Answer 185

light gray

Answer 186

bright supresses CSF making it easier to see extra fluid

Answer 187

similar to CT angiography, you inject contrast to visualize vasculature ex. you can see aneurysms

Answer 188

a bulge or ballooning in the wall of a blood vessel

Answer 189

Gadolinium (Gad) is a non-toxic paramagnetic contrast enhancement agent that is injected during a scan. It shortens the T1 showing up brighter on T1-weighted images. particularly good at showing vascular damage and breakdown of blood brain barrier

Answer 190

Detects the diffusion of water protons in tissue. More uniform diffusivity results in bright DWI signals. White matter fiber bundles consist of the tube-like parts of cells that behave like straws constraining water diffusion. Ischemia causes sodium-potassium pumps to shut down resulting in the influx of water into the intracellular space through osmosis.

Answer 191

C) It gets brighter because more water is trapped inside cells. in normal tissue, theres going to be more free movement of water molecules (darker tissue appearance) if the tissue has become more pathological, ex. cell death, you'll get an influx of water ad molecules will be more constraint, giving a brighter color.

Answer 192

diffusion tensor imaging (kind of diffusion-weighted imaging) specifcally tracts axons using the idea that diffusion (ex. water molecules) is going to be different in axons, compared to gray matter. Interrogates the 3D shape of diffusion to provide measures of mean diffusivity (direction) and fractional anisotropy (a proxy for white matter tract integrity). DTI assesses the structural connectivity between brain regions. Used for surgical mapping, evaluating edema, and detecting tumor boundaries. becomes complicated by the ‘crossing fiber problem’ of white matter tracts in the brain.

Answer 193

patient with a tumor. sometimes surgeons do DTI to map out white matter pathways, because sometimes a tumor can displace them and you want to avoid cutting those pathways.

Answer 194

arterial spin labeling A radiofrequency pulse is applied to the arteries in the brain at the neck in the carotid artery of the blood going up to the brain, then they can trace where that blood actually goes. brighter colors - more blood flow

Answer 195

a brain tumor that grows from astrocytes

Answer 196

Measures metabolic correlates of neural activity. 1. Positron Emission Tomography (PET) 2. functional MRI (fMRI)

Answer 197

Positron Emission Tomography (PET) you inject special radioactive tracer that is built like whatever biomolecule you are interested in studying, but with radioactive element. those tracers behave like the regular biomolecules, but because they are radioactive, they decay and that decay can be measured to understand how those neurochemicals are working. PET detects pairs of gamma rays released from positron-emitting radioactive tracers, e.g. 15O, 18F. Tracers are injected into the body and behave like biologically active molecules. The location of emitted particles can be measured as they are released over the course of radioactive decay. Many tracers have been developed for specific neuroreceptor subtypes and plaques.

Answer 198

PET scan measures glucose PiB PET Alzheimer’s disease (AD) typically shows reduced glucose metabolism in affected brain regions, especially in the parietal and temporal lobes, using FDG-PET (Fluorodeoxyglucose PET).

Answer 199

functional MRI allows you to detect changes in activity related to neurons firing (but not directly) Detects the change in oxygenated to deoxygenated hemoglobin in the blood - blood oxygen level dependent (BOLD) signal. Oxygenated hemoglobin is paramagnetic and deoxygenated hemoglobin is diamagnetic. Both are detectable with MR. (Seiji Ogawa, 1990) BOLD is a proxy for relative changes in neural activity since O2 is metabolized when cells fire and need to replenish energy. Because the signal is related to blood flow changes it has LOW temporal resolution, despite great spatial resolution

Answer 200

is the process that increases blood flow to the brain in response to neuronal activity. This process ensures that oxygen and nutrients are delivered to areas of the brain that are active

Answer 201

can be used to guide surgeries. fMRI can localize which side language is on, motor activation, etc. This is especially helpful when tumors remap where functions are localized.

Answer 202

Magnetic resonance spectroscopy looking at proton spins to measure neurochemicals or metabolites MRS measures the precession of hydrogen protons (1H) of molecules. Because many brain molecules exist in relatively low concentrations measurements must be taken from larger regions of interest, usually 1-10 cm3. Only small mobile molecules >/= 0.5 μmol/g tissue contribute to the MRS signal. Most neurotransmitters exist below this level of concentration, but some are measurable, e.g. glutamate, GABA, and aspartate. Instead of forming an image, MRS analyzes the frequency shifts in the MR signal due to chemical environment differences in hydrogen or other nuclei. The spectral data reveal the relative concentrations of metabolites.

Answer 203

This technique can be used to differentiate tumor types, for example, distinguishing between benign and malignant brain lesions. Additionally, MRS can be helpful to assess neurodegenerative diseases or investigate metabolic disorders.

Answer 204

Advantages: 1) Safety - Far less radiation exposure compared to CT (essentially none) - Non-invasive 2) Multiple types of images can be obtained. 3) Easily combined with other techniques. 4) Fast and getting faster! 5) Fairly comfortable. Pulse Radiology Education

Answer 205

Disadvantages: 1) Safety - Strong magnetic fields pose risks to individuals with ferrous metals in their bodies - Potential for tissue burns - Loud! (earplugs) 2) Difficult to use in certain populations, e.g. kids or patients with movement disorders 3) Expensive 4) Different types of images depend on different kinds of expertise.

Answer 206

therapy. less invasive than deep brain stimulation, even though it still involves surgery. a battery is implanted under the skin. a wire goes up and wraps around the vagal nerve to stimulate and effect brain activity. seems to reduce seizure activity.

Answer 207

typically when you do implantation of brain stimulation, you implant it then you wait a couple of weeks to get surgical recovery before they turn it on. however, in this case study a quicker response was needed (she was pregnant), because they deemed that the risk of having more seizures was greater than the risk of turning it on. woman had epilepsy, but it got much worse during pregnancy, to the point that she was frequently having seizures, which is dangerous because having these seizures and potentially falling because of them are increasingly severe for her and the fetus.

Answer 208

- treat the tumor less aggressively - they didn't have to do the extensive mapping

Answer 209

prior to surgery the did fMRI to understand what was going on, then when they went in they did direct electrical stimulation with recording

Answer 210

there was a whole teamL neuroscientists (ex., defined the task), surgeon (performed the surgery and stimulation), neurologist (ex., the patients doctor)

Answer 211

- balancing the retention of the tissue that is functional with appropriately treating the tumor.

Answer 212

they can show how you can plan to retain special functions (ex., music). also shows you could potentially just use fMRI for mapping before surgeries -- rather than just going into the surgery

Answer 213

someone who is receiving a similar procedure should be able to digest the information and bring it to their doctor

Answer 214

type of ray (fish) that delivers strong electric shocks. in the past, people would use it to treat headaches.

Answer 215

cortex is stimulated during surgery to map out function and try to preserve healthy function. ex., someone getting surgery, they would stimulate around the healthy tissue as much as possible in hopes of preserving as much healthy tissue as possible. Mapping is performed with a small bipolar electrode placed on the surface of the cortex. Numbers are placed directly over areas that disrupt behavior or alter sensation when stimulated. Requires patients to be awake during surgery.

Answer 216

using direct cortical electrical stimulation they would stimulate and see if people would move / stop moving or if they had perceptual feeling

Answer 217

still considered the gold standard, but there are some limitations - stimulating randomly, so you actually are getting action potentials going in both ways in the neurons (you dont have that refractory period) -- makes it less similar to nature - you can accidentally hit passing fibers - cells can be impacted, even if they are a bit further from the target cell. Direct electrical microstimulation influences a sparse population of cells.

Answer 218

- Small electric currents are passed through the brain to induce a seizure as treatment of Psychiatric disorders including severe depression, mania, catatonia, and aggression in patients with dementia. - Used for people who have medication-resistant disorders or for populations that cannot take medication. Also works quickly. - Patients are under general anesthesia and a muscle relaxant during stimulation. - Electrodes are placed bilaterally on the head or unilaterally, with one electrode over the temple and one over the vertex. - Stimulation is brief typically just a few milliseconds to ~6 seconds. (quick therapy) - the thought process behind this was that people with some conditions get stuck in sort of the same brainwave pattern, so this would hopefully help break it up (disrupting electrical activity in hopes of it 'ressetting').

Answer 219

non-invasive brain stimulation method uses magnetic fields to generate electric field and alter brain activity. Faraday was the first person to create a coil to induce a magnetic field

Answer 220

TMS = transcranial magnetic stimulation electric current is sent through the coil. opperates under the property that a change in a magnetic field induces an electric field. if you place the coil to the head, magnetic field travels easily through the skull to induce an electric field. -- you can stimulate neurons (ex., neuron pathways that will make your finger twitch)

Answer 221

The geometry of the coil determines the focality of the magnetic field and of the induced current, and hence also of the targeted brain area. Superficial layers (cortex or gray-white matter junction) the shape creates a more focal magnetic fields. figure 8 shape = consolidated circle; ring = giant ring

Answer 222

- determines the direction of the induced current - relationship between current direction and cytoarchitecture will determine the extent of neural firing

Answer 223

- greater intensity = reduced focality - effective intensity is also determined by scalp-cortex distance

Answer 224

stimulating over motor cortex can excite the pyrimidal neurons, excitation travels down the corticospinal tract and can be recorded with surface EMGs

Answer 225

MEP = motor evoked potential ** most important SICI = short-interval intracortical inhibition ICF = intracortical facilitation

Answer 226

on average, certain diseases are associated with reduced motor evoked potentials

Answer 227

- Unlike standard TMS, which delivers pulses at a consistent rate, event-related TMS precisely times the stimulation to coincide with the moment of interest in an experiment, like when a specific visual image appears on a screen. (e.g. 10 Hz) - Transiently disrupts targeted brain region - Provides approximate information about when a brain region “comes online” (likely have to test many different time-points to be confident in timing) - Determines if a brain region is necessary - people sometimes call it a "temporary lesion"

Answer 228

non-invasive stimulation method - Hypothesized to cause a polarity dependent shift of the resting membrane potential, i.e. make neurons more or less likely to fire an action potential. - Anodal tDCS is believed to enhance excitability, and cathodal tDCS is believed to reduce excitability. - After-effects have been reported to last on the order of an hour. - Many studies have assessed interactions with pharmacology. - A couple published trials in epilepsy and major depression.

Answer 229

electric fields can't pass through the skull as easily as magnetic fields

Answer 230

recent work questioned the efficacy. study used cadavor to add electrodes to see if neural activity could be evoked. - A study placed electrodes on cadavers and found that tDCS did not generate enough electric fields to evoke neural activity. - Since cadavers lack active neurons, this study suggests that tDCS may not generate strong enough currents in living brains to reliably influence neural firing.

Answer 231

tDCS = direct current tACS = alternating current tPCS = pulsed current tRNS = random noise t = transcranial S = stimulation

Answer 232

invasive - Involves surgical implantation of electrode leads targeted at specific neuroanatomical structures (more on this in the next lecture). - These electrodes deliver continuous electrical pulses to modulate abnormal neural activity. - DBS is used to treat motor disorders, epilepsy, chronic pain, OCD, and mood disorders. - Stimulation parameters vary in voltage (1~3.5 V), frequency (130~185 Hz), and pulse width (60~210 μs). *extra slack is given so that if theres tugging it wont come out of the brain

Answer 233

- Tailoring stimulation programming on an individual basis. - Consideration of symptoms, side effects, interactions with medication, and battery life (avoid frequent surgical replacement). - Methods for improving DBS include using recordings of patients’ own brain activity to detect signatures of pathology and then adjust stimulation in a ‘closed loop.’

Answer 234

a. method of direct cortical stimulation for mapping

Answer 235

b. T2 weighted MRI

Answer 236

a. It has low temporal resolution

Answer 237

d. the forward problem

Answer 238

b. the newborn hearing test

Answer 239

a. it has low temporal resolution

Answer 240

A 31-year-old previously healthy woman developed altered mental status and multi-organ failure, including hypotension, renal failure, hemolytic anemia, and fevers, after inhaling vaporized synthetic marijuana ("Buzz Juice") over two days; her neurologic exam revealed confusion, visual hallucinations, ataxia, dysarthria, and hyperreflexia, while MRI findings were consistent with toxic leukoencephalopathy. Buzz Juice contained JWH-081, a potent CB1-receptor agonist that impairs cognitive function and reduces GABA release, leading to neurotoxicity, cardiovascular instability, renal failure, and respiratory depression; similar radiographic findings have been seen with other recreational drugs like heroin and toluene, likely due to oxidative myelin damage. Her husband, who inhaled the drug in a much smaller quantity, remained asymptomatic, suggesting either individual variability in toxicity susceptibility or a dose-dependent effect, highlighting the need for further research on synthetic cannabinoids' clinical and radiographic correlations.

Answer 241

An 89-year-old male with vascular dementia presented to the ER after a fall, with family reporting a rapid cognitive decline, aggressive behavior, word-finding difficulty, and staring spells over the past six months. Brain imaging (T1 and T2 weighted MRI) revealed an extra-axial fluid collection in the right frontal, parietal, and occipital regions, causing mass effect, midline shift (11 mm), subfalcine herniation, and septations in the subarachnoid space. The most likely diagnosis is arachnoid cysts.

Answer 242

A 44-year-old man with a history of postnatal hydrocephalus treated with a ventriculoatrial shunt developed mild left leg weakness, which had previously occurred at age 14 and resolved after shunt revision. Neuroimaging revealed massive ventricular enlargement, a thin cortical mantle, and a posterior fossa cyst, with a diagnosis of non-communicating hydrocephalus likely due to Magendie’s foramen stenosis. After partial improvement with neuroendoscopic ventriculocisternostomy (they made a small hole in 3rd ventricle to improve flow), his symptoms recurred but resolved completely following a ventriculoperitoneal shunt, though his IQ (75) and neuroimaging findings remained unchanged.

Answer 243

Nocturnal frontal lobe epilepsy (NFLE) is a sleep-related seizure disorder often misdiagnosed as parasomnia, requiring nocturnal sleep EEGs for accurate diagnosis. In Case #1, a 14-year-old boy experienced generalized tonic seizures exclusively during sleep, with conventional EEGs showing no abnormalities until a sleep stage II EEG revealed sharp wave bursts in the right frontal lobe, leading to an NFLE diagnosis and symptom resolution with CBZ. In Case #2, a 12-year-old boy had a history of night terrors and a single daytime seizure; his nocturnal sleep EEG revealed high voltage sharp wave bursts in the frontal lobe, confirming NFLE, and his symptoms resolved after switching from CBZ to ZNS due to auditory side effects.

Answer 244

A 54-year-old man with a 3-year history of loss of libido, erectile dysfunction, and anxiety, along with recent polyuria, nocturia, and polydipsia, presented with signs of visual failure, including left temporal hemianopia, impaired color vision, temporal disc pallor, and right optic nerve enlargement. Clinical findings showed hypo-gonadotrophic hypogonadism and mildly elevated prolactin, prompting a brain MRI. The most likely diagnosis is one of the following: spindle cell oncocytoma (tumor in the pituitary gland)

Answer 245

A 21-year-old pregnant woman with refractory epilepsy, experiencing 3–7 seizures per week despite multiple antiepileptic drugs (AEDs), underwent vagal nerve stimulation (VNS) implantation at 32 weeks of pregnancy to improve seizure control while minimizing fetal risk. The procedure, performed under general anesthesia with obstetric oversight, resulted in a significant seizure reduction and an uncomplicated cesarean delivery of a healthy baby at 37 weeks. While VNS has been shown to be effective in reducing seizure frequency in refractory epilepsy, this case highlights its successful use during pregnancy, warranting further studies on long-term maternal and fetal outcomes.

Answer 246

A 26-year-old musician (Patient AE) with a low-grade tumor in the right temporal lobe underwent pre-operative fMRI, which localized music processing to the right posterior superior temporal gyrus (STG), and later underwent awake intraoperative brain mapping during a melody repetition task. Electrical stimulation of the right STG induced "music arrest" and pitch errors without affecting language, providing causal evidence for the functional segregation of music and language processing in the brain. The study confirms the right STG's specific role in melody processing and suggests interactions with the right inferior frontal gyrus via the arcuate fasciculus, with future research needed to explore real-time neural dynamics in music processing.

Answer 247

Five patients with trigonal (lateral ventricle) tumors underwent preoperative navigated transcranial magnetic stimulation (nTMS) motor and language mapping, corticospinal and optic radiation tractography, and neuronavigation-based surgical planning between 2014 and 2016. Four patients proceeded with surgery via a transparietal approach, guided by nTMS and tractography to avoid eloquent brain structures, with favorable neurological outcomes except for one case of temporary dysarthria and another of persistent mild hemiparesis. One patient refused surgery, but overall, the study demonstrated that integrating nTMS and tractography into neurosurgical planning enhances surgical precision and helps mitigate risks to motor, language, and visual functions.

Answer 248

used to treat mental illnesses. initially removal of parts of cerebral cortex in 1930s focused on frontal lobe. lobotomy involved cutting fibers / connections between prefrontal cortex and rest of the brain

Answer 249

orbitoclasts were inserted through eye sockets and used to sever brain connections. allowed the procedure to be done outside a hospital

Answer 250

reduced intracranial pressure - hydrocephalus - removing skull following trauma remove diseased / damaged tissue - tumor resection - gamma knife - epilepsy removal - lesion for movement disorders treat function - DBS, ultrasounds

Answer 251

caused by any kind of build up of pressure in the skull characterized by: - headaches - nausea / vomiting - gait problems sometimes: hypertension, bradycardia

Answer 252

- CSF isnt draining properly putting pressure on the brain - babies are extra susceptable because their skull isnt fully closed so it keeps getting bigger and bigger

Answer 253

- treatment for hydrocephalus - a valve - can be implanted to drain excess CSF into the abdomen when pressure reaches a certain level - CSF is either funneled into abdomen or to heart

Answer 254

- blood build up causes intracranial pressure - treated using burr hole or decompressive craniectomy

Answer 255

swelling after trauma can take months to heal. piece of skull is removed and either stored on ice or inside a patient while they wait for swelling (pressure) to go down. skin is replaced but is squishy so brain can expand

Answer 256

ischemic and hemorrhagic

Answer 257

more common blockage of blood vessel from plaque or clot causing blood to stop going to an area. as a result, tissue dies -- blood thinners okay

Answer 258

burst of blood vessel causing blood to pool. blood is leaking into brain --> causing less blood to get to tissues -- no blood thinners

Answer 259

brain aneurysm

Answer 260

- weakening or bulge in blood vessel of the brain - unruptured is usually without symptoms, although occasionally large ones can cause symptoms if it is pushing on the brain or nerves. - rupture is a medical emergency (hemorrhagic stroke or subarachnoid hemorrhage)

Answer 261

- weakened blood vessel - high blood pressure - congenital or can develop later in life -- ateriovenous malformation (AVM) tangle of abnormal blood vessels in the brain which are more prone to rupture

Answer 262

after rupture - surgery may be done to stop bleeding or reduce intracranial pressure before rupture - clipping aneurysm --> putting a clip that prevents blood from accessing polyp (bulge) of blood - endovascular repair ("coiling") --> wire inserted into the polyp (bulge) of blood to prevent blood from going in there and promotes clotting

Answer 263

- typically arise from spreading from other body parts or from glia cells, rarely neurons - surgery to remove the tumor is the usual treatment - less defined boarders on cancerous tumors because its spreading

Answer 264

- some brain tumors like meningiomas are benign so they will not spread - however surgery is sometimes still necessary to reduce intracranial pressure and reduce symptoms which may result from the mass pushing on the brain - getting the whole tumor out may be less critical in this case - more defined boarder on tumors -- less necessary to get it ALL out (you can leave a lil bit)

Answer 265

- gold standard to use electrical stimulation and look for motor or speech arest - sometimes fMRI or intercranial EEG is now used - wada test can also be used to localize language hemisphere

Answer 266

localize language hemisphere. barbituate injected into carotid artery that goes up and puts one hemisphere to sleep but not the other. they will then see if person loses the ability to talk or not

Answer 267

B **meningioma so less aggressive cancer -- its okay if we leave some in there

Answer 268

- uses radiation to kills cells in a targeted way - gamma ray radiation is sent to converge on a target, so outside of that target there is minimal impact on nearby tissues - not effective enough for large malignant tumor, but smaller benign tumors works well for this. cells die slowly and it takes a while for waste to get removed

Answer 269

nothing structurally wrong but something is altered with function in epilepsy sometimes tissue may appear healthy but neurons fire abonrmallu parkinson's disease is thought to be caused by excessive neuronal activity in certain regions

Answer 270

- Lesions can be placed in one of these three areas: STN (Subthalamaic Nucleus) or Gpi (Globus Pallidus Internus) (occasionally thalamus) to reduce symptoms. - Down side is that they are not adaptable/reversible --> can be useful if someone can't come back to the hospital often

Answer 271

it is reversible and adjustable. DBS is more than just a lesion. One way DBS may work is by reducing pathological brain rhythms.

Answer 272

Correct placement in Gpi or STN is often determined by “listening” to the neurons firing (in addition to imaging)

Answer 273

while doing DBS in surgery, doctor asks patient to raise hand and bring toward mouth like they are drinking water. with DBS off, patient is extremely shaky. withe DBS on, patient is no longer shaky at all.

Answer 274

doesn't involve cutting - Focused ultrasound can be used to lesion tissue - A good approach for people for whom surgery is not a good option. - Most applicable to tremor. - Similar approaches can be used to treat other disorders where damaging tissue is the goal. - Not adjustable like DBS, but no hardware to manage.

Answer 275

C) Recommend focused ultrasound

MT 1 Flashcards

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