neuropsych review pt 2

golgi staining procedure

• stains some neurons (but not all) black

• first kind

• good to show shapes of neurons

nissl staining procedure

stains neuron bodies in light pink

advantages of cranial X-rays

• cheap

• widely available

• shows fractures, hemorrhages, tumors, etc.

disadvantages of cranial X-rays

• radiation

• poor discrimination between brain tissue and CSF

• 2D images

what is angiography used for

diagnostics only - aneurysms, tumors, vasculature shifts due to lesions / tissue degeneration

is angiography risky

radiation, bruising potential

higher radiation in CT scan or cranial X-ray? why?

CT; more scans being done

EEG waves when resting

alpha waves, medium (increasing) amplitude, medium (lowering) frequency

EEG waves during a coma

slow, low amplitude waves, not deep sleep

differences between REM and NREM sleep - movement of limbs

• REM no movement

• NREM movement

how does the % of REM sleep change during lifespan

80% REM for babies, 25% REM for adults, older people have even less

immune system / sleep connection

less sleep decreases immune function

90 minute thing with sleep

• time it takes for one "sleep cycle"

• naps should be multiples of 90mins

types of insomnia based on how long they last

transient ≤ week, acute ≤ month, chronic >month

in which order are the brain lobes "epileptogenic"?

temporal 30-50%, frontal 20%, parietal 6%, occipital 5%, some mixed

vitrius humor

gel-like substance between lens and retina, keeps optic parameters stable day to day

name the nerve that transmits information from the cochlea

• cranial nerve VIII

• vestibulocochlear

• statoacoustic

• auditory

• acoustic

histology

study of tissues

myelin staining procedure

• stains axons (myelin)

• shows connections between neurons and neuronal pathways

cranial X-rays

• distinguishes between high density (bone, shown white) and low density (shown dark) areas

• skull fractures, hemorrhages, tumors, etc.

angiography

• visualizations of cerebral vasculature

• catheter is inserted via an external artery then ran to artery of interest

• contrasting dye is injected

BED

banana equivalent dose, shows radiation in an easy-to-understand mannner

clonic

jerking

retina

• back of eye, actually processing light, rods and cones

• rods: 120 million, detects light vs dark

• cones: 6 million, detects RGB

what is processed in MT (V5)

motion

what do tumors like and where is it

• SUGAR

• in blood vessels

CT or CAT scans

computerized axial tomography

general process for CT scans

thin slice x-rays at many angles, rotates and takes many mini scans, computer reconstructs this into a 3D image

similarities/differences between CT scans and cranial X-rays

• radiation

• CT > C Xrays

• 2D vs 3D

disadvantages of CT scans

• reliable electricity needed

• radiation

MRI

• magnetic field applied to brain

• aligns to natural spin of the atoms in body’s water molecules which emits electromag energy in the process

• complex, high-tech structural imaging of brain

DTIs

MRI that measures water diffusion at a location, shows preferred direction, allows for visualization of directional fibers, shows any areas with reduced diffusion; finds areas of partial/complete disconnection

MRI disadvantages

• expensive

• need to stay still

• takes very long

• no metal

MRIs..

• what types of things can be measured

• research

• complex image of brain structures

• volume/shape of cortical, subcortical areas

what types of disorders are DTIs interesting/relevant to

demyelinating diseases like multiple sclerosis (MS)

types of scans that show structure

• x-ray

• CAT scans

• angiography

• MRI

• DTI

fMRI

dynamic image of brain functionality, tracks oxygen consumption, measures regional CBF

subtraction in fMRI

take a baseline fMRI, then one during which a stimulus is included, and subtract resting cerebral blood flow from the action CBF

what process is used to visualize brain processing via BOLD imaging

fMRI (Blood-oxygen-level-dependent imaging)

difficulties with fMRIs and effects

• have to be very still/bite a bar

• noisy/claustrophobic

• hard for young, old, people with disabilities

research approaches for fMRI

• task-based (activation levels or MVPA)

• resting state

• brain connectivity

activation levels vs. MVPA

oxygenated blood activity vs. neuronal activity

why is brain connectivity of interest to researchers

• how the brain works

• how it interacts with itself

• localizing function

two types of PET imaging used in Alzheimer's research

beta amyloid density

synaptic function

advantages and disadvantages of PET

advantages; good at showing location of function, high res imaging, cool colors

disadvantages; positron radiation, not as complex image fMRIs, semi-invasive bc of injection

what is it that PET does that fMRIs do better

• complex imaging of brain

• task-based activity

Positron Emission Tomography

earlier version of fMRI

injecting radioactive tracers (glucose, neurotransmitters) and tracking where they go in the brain

three types of electrical recordings of brain activity

• single-cell recording

• EEG

• ERP

single cell recordings

• thin electrode implanted in an animal's brain next to one neuron or many

• can record singular action potentials or many

• only works in one small area at a time

ElectroEncephaloGraphic recording

• records brain waves/electrical activity across the brain through the layers of the membrane

• records collective and synchronous activity of neurons in the cortex

EEG setup

stretchy cap, gel to conduct electrodes placed on the skull, leads/wires all around

EEG used for

changes in consciousness:

• sleep

• epilepsy diagnosis

• depth of anesthesia

• normal brain function

Event Related Potentials

give people a stimulus during an EEG and record the blip, compare to baseline EEG

averaging in ERPs

• removes "background noise"

• aka the chance that recorded difference from original EEG is due to confounding variable

• like subtraction in fMRIs

MagnetoEncephaloGraphy

measures magnetic potentials produced by brain activity, requires room with no outside magnetism, strength of magnetic field doesn't vary, able to indicate cortical depth, better at diagnosing epilepsy

optical imaging

1. light through skull, scalp, CSF, and brain tissue

2. measures light that bounces back

3. gives info about source/time course of neural activity, blood flow to active areas

4. can be done on people who can't do fMRIs

Transcranial Magnetic Stimulation

application of intense magnetic fields to temporarily inactivate/scramble neurons

• used in research

• used in therapy (electroconvulsive therapy but much more developed)

  • factory reset

transcranial Direct Current Stimulation

• applies weak electrical signals

• clinically used to slow alzheimers onset, reduce cravings/addiction, reduce auditory hallucinations

• electrodes and such

parts of a polysomnogram, and why is this important?

EEG (brain), EOG (eyes), and EMG (muscles)

EEG waves when awake

beta waves, low amplitude, high frequency

two weird phenomena during stage 2 sleep on EEG

sleep spindles and K complexes

EEG waves during deeper sleep (3 & 4)

delta waves, high amplitude, low frequency

NR3 / N3

delta/slow wave sleep, stages 3 & 4

general trend in the amplitude/frequency from awake to deep sleep

amplitude increases, frequency slows

Explain the sleep cycles that one goes through in a normal night (both stages and REM/NREM alternation).

5 NREM, 4 REM

what is the trend for slow wave sleep and REM sleep during the night? how many REM cycles during a "normal" night?

slow, REM, slow, REM, slow, REM, slow, REM, slow (4 rems 5 slow waves)

differences between REM and NREM sleep - movement of eyes

REM movement, NREM no movement

circadian rhythm

rhythm of about a day, system that runs through the SCN in the hypothalamus

which pathway acts on which part of the brain in circadian rhythms

the retinohypothalamic pathway acts on the superchiasmatic nucleus (SCN; in hypothalamus) - light on retinoganglion cells helps to set to the 24-hour cycle

pineal gland with circadian rhythm

directed by hypothalamus to make melatonin

entrainment of the circadian system

light-entrainment - light shining on retinas resets the brain back into the 24-hour cycle, helpful for jet-lag and such

three main views on the function of sleep

• memory processing

• recuperation/cleaning

• adaptation

• or all of the above

CSF circulation / sleep connection

glymphatic system circulates CSF and removes excess stuff during sleep

glymphatic system / alzheimer's connection

glymphatic system removes excess beta amyloid; beta amyloid buildup has been shown to increase chance of alzheimer's

what did the longer movie clip (Neil deGrasse Tyson & rats in maze) suggest happens during sleep and during which type of sleep

replay of day's memories during NREM, important ones stored, rest discarded

'prelearning' value of sleep

sleep consolidates memory, empties your hippocampus so you’re ready to receive new information

two processes for consolidation of memories during sleep

• during stage 2 sleep, sleep spindles consolidate memory, and then a record is sent to cortex for long-term storage

• hippocampus emptied

What was the third way in which you improve 'knowledge' during sleep?

Integration during REM (connections are made in the information you just learned)

sleep pressure

adenosine builds up during the day making you sleepy, this adenosine buildup is cleared out during sleep

cognitive effects of sleep deprivation

• increased sleepiness

• faster sleep onset

• poor mood

• poor vigilance

• poor executive function

physical effects of sleep deprivation

lower temp. and immune function, higher BP; hormonal and metabolic changes

emotional effects of sleep deprivation

poor mood, crankiness

going to bed too late vs waking up to early cuts into…

NREM sleep vs REM sleep

caffeine and sleep

prevents sleep, effects quality, interrupts NREM

alcohol and sleep

• sedation ≠ sleep

• stops firing of cells in prefrontal cortex

• fragments sleep

• blocks REM

REM sleep important for

emotional/mental health and creativity

three sleep disturbance patterns that count as insomnia

• trouble falling asleep

• trouble staying asleep

• waking up too early

incidence of insomnia

1 in 4 adults

sleep hygiene measures

• regularity/consistency

• no light, sound

• cool temp.

• no big meals 3hrs before bed

• magnesium supplements maybe

blue light effect on sleep

activates the retinol ganglion, induces awake-ness, don't have 1hr before bed

sleep apnea

breathing is stopped during sleep, causing the person to wake up and gasp for air

prevalence of sleep apnea

3-4%

obstructive sleep apnea

85% of sleep apnea, tongue blocks airway

central sleep apnea

body messes up the breathing signals during sleep, 6%

can sleep apnea be a mix of obstructive and central

yes, 9%

standard therapy for sleep apnea and the problem with it

CPAP - continuous pushing of air

problem being its hard to get used to

incidence of narcolepsy

20-45 out of 100,000

symptoms of narcolepsy

sleep attacks w or w/o cataplexy, sleep paralysis, hypnagogic hallucinations, daytime sleepiness, poor memory/concentration

types of narcolepsy

• with cataplexy

• without cataplexy

• result of a medical condition

cataplexy vs sleep paralysis

slumping over vs. not able to move when you wake up