Brain Imaging, Sleep, Epilepsy, Vision and Audition: Exam 2

What is histology?

The study of tissues and their structure and morphology.

What is the purpose of staining the brain in histology?

To make neurons visible for study.

What does the Golgi stain show?

It shows neuron distribution in different parts of the brain.

What do Nissl stains target?

They stain cell nuclei.

What is the purpose of myelin stains?

To visualize myelin in the brain.

What is a tracing procedure in brain imaging?

Injecting a substance in one area to trace its circulation throughout the organ.

What are cranial X-rays used for?

To discriminate low and high density regions in the skull.

What appears white on a cranial X-ray?

High density tissue areas, such as bone.

What are the limitations of cranial X-rays?

Poor discrimination between brain tissue and CSF, 2D images, and poor structural resolution.

What is a CT scan?

A computerized axial tomography scan that constructs images from X-ray measurements taken at various angles.

What does angiography visualize?

Cerebral vasculature by injecting a contrasting dye into blood vessels.

What is the main use of MRI?

To image the brain using a powerful magnetic field.

What is the BOLD signal in fMRI?

Blood Oxygen Level Dependent signal that indicates oxygenated and de-oxygenated areas of the brain.

What is the purpose of diffusion tensor imaging (DTI)?

To visualize the preferred direction of water diffusion and identify white matter tracts.

What is functional MRI (fMRI) used for?

To produce moving images of brain activity based on oxygen consumption.

What does PET imaging utilize?

Radioactively labeled glucose to detect areas of high metabolism in the brain.

What is single cell recording?

An electrophysiological procedure that records the activity of individual neurons.

What is EEG used for?

To record electrical activity of the brain, useful for sleep studies and epilepsy.

What are event-related potentials (ERPs)?

Brief changes in EEG signals in response to discrete sensory stimuli.

What does magnetoencephalography (MEG) record?

Magnetic potentials produced by brain activity.

What is transcranial magnetic stimulation (TMS)?

A technique that applies intense magnetic fields to temporarily inactivate neurons.

What does transcranial direct current stimulation (tDCS) do?

Uses weak electrical currents to increase or decrease neuronal activity.

What is the significance of cortical thickness in brain structure analysis?

It helps in comparing differences in brain volume between groups.

What does diffusion tractography utilize?

Information from DTI to build images of probable white matter tracts.

What is the role of subtraction techniques in fMRI?

To isolate brain activity related to specific tasks by removing non-related activity.

What can DTI detect in relation to brain disorders?

Reduced diffusion in specific regions due to demyelinating disorders.

What is the main diagnostic use of angiography?

To visualize aneurysms, tumors with new vasculature, and vascular shifts due to lesions.

What does the Golgi stain do?

It silver stains neurons for neuron distribution.

What is the purpose of the Nissl stain?

It stains cell nuclei for neuron density and injury.

What does the myelin stain visualize?

It stains myelin to map tracts or find demyelinated areas.

How do cranial X-rays work?

They use radiation to create a 2D image of the brain showing low density (darker areas) and high density (lighter areas) structures.

What can cranial X-rays show?

They can show brain bleeds, fractures, and tumors.

What are the advantages of cranial X-rays?

They are cheap and easy to use diagnostic tools.

What are the disadvantages of cranial X-rays?

They have poor resolution and radiation can accumulate.

What is angiography used for?

It visualizes blood supply in an X-ray or CT scan to detect aneurysms, tumors, and vascular changes.

What is a risk associated with angiography?

It involves risks from radiation and injecting a contrast medium.

How does computerized axial tomography (CT) differ from X-rays?

CT uses an X-ray scanner that rotates to take multiple images from different angles, creating a 3D image.

Which has a higher radiation dose: a skull X-ray or a head CT?

A head CT has a higher radiation dose because it takes multiple photos at different angles.

How does an MRI work?

It uses a magnetic field to align the spin of atoms in water molecules and radiofrequency signals to visualize brain structure.

What are the advantages of MRIs?

MRIs provide detailed images of brain structures without radiation exposure.

What does DTI measure?

Diffusion Tensor Imaging (DTI) shows the preferred direction of diffusion and visualizes directional fibers in the brain.

What disorders can DTI help investigate?

It can help investigate demyelinating disorders like multiple sclerosis and brain connectivity changes across life stages.

What does an fMRI measure?

Functional MRI (fMRI) measures brain activity based on oxygen consumption, producing detailed images of brain function.

What is the purpose of subtraction techniques in fMRI?

They isolate brain activity related to specific tasks by removing non-relevant activity.

What are task-based and resting-state research approaches in fMRI?

Task-based approaches measure activation levels during tasks, while resting-state approaches assess brain connectivity without tasks.

Why is brain connectivity important in research?

It links specific brain structures to functions and helps understand how connections relate to tasks.

How does PET imaging work?

Position Emission Tomography (PET) records emissions from injected radioactive chemicals to produce high-resolution images.

What is PET used for?

PET is used to detect areas of high metabolism, such as in cancer or Alzheimer's disease.

What are the advantages of PET over fMRI?

PET is better at measuring specific metabolic processes, like glucose metabolism.

What types of electrical recordings of brain activity exist?

EEG (electroencephalogram), EOG (electrooculogram), and EMG (electromyography).

What is the process of single cell recordings?

An electrode is inserted adjacent to a neuron to record its activity, commonly done in animal studies.

What can EEGs be used to study?

EEGs can study sleep, epilepsy, anesthesia depth, and normal brain function.

What is magnetoencephalography (MEG)?

MEG records magnetic potentials produced by brain activity, primarily used for epilepsy diagnosis.

What is optical imaging in neuroscience?

Optical imaging shines light on the scalp to gather information about neural activity, reflecting blood flow.

What is polysomnography?

The study/recording of sleep patterns.

What are the primary methods for measuring sleep?

EEG (electroencephalogram), EOG (electrooculogram), and EMG (electromyogram).

What EEG pattern is associated with an alert awake state?

Beta Rhythm.

What EEG pattern indicates a calm and resting state?

Alpha Waves.

What EEG pattern is observed during deep sleep?

Delta Waves.

What are the two main types of sleep?

REM sleep and Non-REM (NREM) sleep.

What is the distinction between Stage 3 and Stage 4 sleep?

There is no official distinction; both are now referred to as NR3.

What is a Sleep Spindle?

A sudden high-frequency, low amplitude section of a Stage 2 sleep EEG.

What is a K-Complex?

A high-amplitude, low-frequency section of a Stage 2 sleep EEG.

How does the duration of REM sleep change throughout the night?

REM sleep gets longer with each cycle throughout the night.

What is the average duration of a sleep cycle?

About 90 minutes.

What happens to slow wave sleep and REM sleep as the night progresses?

More slow wave sleep occurs in the beginning, while more REM sleep occurs towards the end.

What is the trend in amplitude and frequency from awake to deep sleep?

Frequency decreases and amplitude increases.

What characterizes EEG patterns during a coma?

Very slow, low amplitude waves with low frequencies.

What is sleep pressure?

Gradual tiredness due to the buildup of adenosine.

What role does caffeine play in sleep?

Caffeine prevents adenosine buildup, which can disrupt sleep.

What are some functions of sleep?

Memory consolidation, cleaning (glymphatic system), recuperation, and repair.

How does the percentage of REM sleep change with age?

Infants have about 50% REM, adults around 25%, and older adults 18-20%.

What is the Circadian Rhythm?

The day/night sleeping cycle regulated by the Suprachiasmatic Nucleus (SCN) in the hypothalamus.

What happens to the pineal gland in response to darkness?

It releases melatonin to regulate sleep.

What is the glymphatic system?

A system that filters cerebrospinal fluid (CSF) during sleep, important for brain health.

What are parasomnias?

Conditions that occur during sleep, typically during NREM sleep.

What is the effect of sleep deprivation on mood and cognitive function?

It can lead to poor mood, decreased vigilance, and impaired cognitive control.

How does sleep affect emotional processing?

REM sleep is thought to play a role in emotional processing and memory.

What is the relationship between sleep and the hippocampus?

During sleep, particularly during spindles, there is a connection between the hippocampus and other brain regions for memory storage.

What is the significance of the CSF circulation findings related to sleep?

It is linked to Alzheimer's disease and the importance of the glymphatic system in clearing waste.

What are the key components of sleep hygiene?

Consistent bedtime and wake time, cool/quiet/dark environment, relaxing before bed, no screens, no food/exercise 2-3 hours before sleep, and caution with caffeine and alcohol.

What is the prevalence of insomnia among adults?

1 in every 4 adults experiences insomnia.

What are the three types of insomnia based on duration?

Acute (less than a month), chronic (more than a month), and transient (less than a month).

What are common sleep disturbance patterns that indicate insomnia?

Waking up and unable to fall back asleep, difficulty falling asleep, and waking up early.

What is the role of sleep hygiene in managing insomnia?

Sleep hygiene is crucial for improving sleep quality and addressing insomnia symptoms.

What is sleep apnea?

A condition where people stop or reduce breathing during sleep.

What are the two main types of sleep apnea?

Obstructive sleep apnea (most common) and central sleep apnea (rare).

How does obstructive sleep apnea occur?

The tongue blocks the airway during sleep.

What is the primary treatment for obstructive sleep apnea?

CPAP (Continuous Positive Airway Pressure) machine that helps keep the airway open.

What is narcolepsy?

A sleep disorder characterized by excessive daytime sleepiness and sudden sleep attacks.

What are the symptoms of narcolepsy?

Sleep attacks, cataplexy, hypnagogic hallucinations, and sleep paralysis.

What is the difference between cataplexy and sleep paralysis?

Cataplexy involves sudden muscle weakness, while sleep paralysis is the inability to move or speak while falling asleep or waking up.

What are NREM and REM parasomnias?

NREM parasomnias include sleepwalking and sleep terrors; REM parasomnias include REM sleep behavior disorder and nightmare disorder.

What is the prevalence of epilepsy?

1-4% of the population will experience multiple seizure episodes.

What is the primary symptom of epilepsy?

Seizures generated by the brain's dysfunction.

What are the two old classifications of seizures?

Grand Mal (tonic-clonic) and Petit Mal (absence seizures).

What are focal seizures?

Seizures that start in one specific part of the brain and may spread.

What is the significance of the 90-minute sleep cycle?

90 minutes is the duration of a full sleep cycle, and napping for this duration helps avoid waking during deep sleep.

How do alcohol and caffeine affect sleep?

Alcohol sedates but disrupts deep sleep; caffeine disrupts adenosine and affects NREM deep sleep.

What are the phases of a seizure?

Aura (pre-seizure), seizure, and post-ictal (after the seizure).