Brain Memory & Language (SHS 350) Flashcards
Action Potential
When neurons send information down the axon
Aneurysm
4
A bulge on a blood vessel
Large aneurysms can press on brain tissue causing external symptoms
Treating aneurysms is possible when they are found before they burst.
Once the aneurysm has burst, the situation become more dire.
Angular Acceleration
4
Occurs when you are hit hard from one side
This causes your head to rotate violently
The neck stops the head head but brain keeps twisting
This is creates Diffuse Axonal Shearing Injury (DAI)
Anterior
Toward the front
Arachnoid
4
Is a transparent and thin layer, web-like
Is thin enough to see the Brain underneath
Its job is to hold in the Cerebrospinal Fluid (CSF)
Is located between the Dura Mater and the Pia Mater
Aristotle
3+2
Aristotle did not like dissections.
The heart is the center of intellect (Cardiocentric Hypotheses)
The brain and the lungs exists to cool the heart. The heart might stop beating if it overheats
- Excitement makes your heart beat faster ergo your heart must be thinking harder - Stabbing someone in the heart will stop their thoughts
Cerebral Arteries
5
Our brain has a lot of arteries because it needs a lot of blood.
1/4 of our blood supply goes to the brain.
The brain’s arteries start out thick and thin out tremendously
Blockages to these arteries can a serious problems because the blockage can prevent an entire section of brain from receiving its blood supply
If a doctor suspects a blockage, they they will inject dye that will allow them to scan for the source
Major Arteries Supplying the Brain
3
Anterior Cerebral Arteries (ACA)
Middle Cerebral Artery (MCA)
Posterior Cerebral Arteries (PCA)
Anterior Cerebral Artery
(ACA)
Supplies the middle areas of cerebral cortex
Middle Cerebral Artery
5
(MCA)
Supplies the outer cerebral cortex
The largest artery in the brain
This artery is the most commonly affected by stroke
Because it is the largest of the three, it is thus the most likely to collect things like plaque that can cause these blockages
Posterior Cerebral Artery
(PCA)
Supplies the back of brain
Astrocyte /ˈastrə(ʊ)sʌɪt/
Astroglia
(2+5)
Star-shaped cells
Provide physical & nutritional support
- Clean up brain debris - Transport nutrients to neurons - Hold neurons in place - Digest parts of dead neurons - Regulates content of extracellular space
Astrocytomas
3
Brain tumor that is most common in adults
Survival rate is pretty good
Cognitive deficits reflect location of the tumor
Axon
3
A long, cable-like projection
Carries an electrical message (nerve impulse)
Can be protected by a myelin sheath
Axon Collateral
An offshoot of the Axon
Can only occur at a Node of Ranvier
Axon Hillock
The triggering zone
Where the electrical signal is sent down the axon
Axon Terminals
Where the electrical signal is converted to a neurotransmitter (chemical signal)
Axon Collaterals can also have Axon Terminals
Axon Varicosities
/ˌvariˈkäsitē/
Presynaptic terminal
A bulge in the axon which has a function similar to an Axon Collateral
Diffuse Axonal Shearing Injury
7
(DAI)
The axons are stretched and torn from the friction
The torn axons will be dead
The stretched axons may never function properly again
DAI usually results in global deficits
DAI often does not show up on brain scans and MRIs unless it is extremely severe
This causes problems for things like auto insurance plans because there seems to be no proof of injury.
Blood Brain Barrier
6
(BBB)
Extra protection for the brain.
Brain tissue is very sensitive and can be easily damaged by stuff that shouldn’t be there
Made up of endothelia cells that are packed tightly to coat the blood vessels
These cells recognize and let good stuff in - like oxygen & glucose
But they keep out the bad stuff - like toxins
rCBF
Regional Cerebral Blood Flow
Benefits of Studying Damaged Brains
3
The study of damaged brains has yielded more information than the study of healthy brains
If someone has a certain area/type of brain damage, then what are the deficits?
If someone has certain deficits, then where is the brain damage?
Causes of Brain Damage
5
Diseases like Alzheimer’s
Infectious Diseases
Tumors
Strokes
TBI
Two Hemispheres of the Brain
Left & Right
Are physically separated from each other, but are connected inside by the Corpus Callosum
“Lower” Brain
1+2
Controls very primitive functions such as heart beats and other things necessary for survival.
Contains:
- Primitive/Reptilian Brain (vital functions-survival) - Limbic System (emotions, fight-or-flight response, etc.)
Brain Scanning Techniques
CT or CAT
(5)
Computerized Axial Tomography
Developed in the 1970s
Combines two dimensional x-ray images to generate a 3-D image of internal organs or body structures
The subject go into a donut-shaped x-ray machine that moves around the person and takes lots and lots of x-ray images
This is the go-to scan for ERs
Brain Scanning Techniques
CT or CAT
Cons
(4)
Radiation exposure
Causing new concerns in the medical community over how many CT scans are being done on children
Low spacial resolution
Bones show up really well, but soft tissues do not
Brain Scanning Techniques
CT or CAT
Pros
(6)
It’s extremely fast
It’s cheaper than an MRI
It’s painless
CAT scans can detect brain damage
CAT scans can highlight local changes in cerebral blood flow while a subject completes a task
Changes in cerebral blood flow indicate brain activity
Brain Scanning Techniques
DTI
(7)
Diffusion Tensor Imaging
Shows how axons (white matter) connects neurons to each other
Gives information on how neural circuits work
It looks at water moving through the brain in the myelin sheath
Shows how quickly water molecules diffuse through white matter tracks and how these tracks are oriented in 3-dimensional space
We are tracking changes in white matter in healthy individuals as they age.
Now know that there are changes in white matter up to the ages of 28-29
Brain Scanning Techniques
High Density Diffuse Optical Tomography
(4)
Has been modified for use with infants
Does not produce radiation
Measures blood and oxygen levels in the brain
Researchers hope to use this to study brain development in babies and to monitor infants during surgery.
Brain Scanning Techniques
EEG
(5)
Electroencephalograph /əlɛktroʊənsɛfələgræf/
The oldest technique for examining brain activity
Gathers electrical signals from electrodes on the scalp that are sent to galvanometers
The galvanometers send this reading to pens which record the electrical signal onto graph paper.
Scientific research requires the subject to wear a lot more electrodes than patients receiving medical tests
Brain Scanning Techniques
EEG
Cons
(4)
Poor spatial resolution
“Skull Smearing” (The skull also conducts electricity and these can affect the test results)
An EEG reads a small group of neurons as if they were all doing the same thing
Cannot measure activity of deeper (subcortical) structures
Brain Scanning Techniques
EEG
Pros
(7)
Quick & inexpensive
Excellent time resolution (≤ 5 msec)
Non invasive procedure
It’s easy to be trained to perform test
Can be used on infants
Can show whether a subject is awake, asleep, or anesthetized.
Can show how long the brain takes to react to stimuli
Brain Scanning Techniques
fMRI
(6)
Functional Magnetic Resonance Imaging
An MRI where the subject completes a task requiring self-awareness in order to activate the frontal lobe
Based on the theory that an active area of the brain has an increased need for oxygen
This increases the oxyhemoglobin concentration in the tissue and decreases the deoxyhemoglobin in the red blood cells
Deoxyhemoglobin reduces the magnetic signal
Oxyhemoglobin is neutral
Brain Scanning Techniques
FNIRS/DOI
(4)
Functional near-infrared imaging/Diffuse Optical Spectroscopy
Uses near-infrared spectroscopy to look at the absorption spectra of water, oxygenated hemoglobin and deoxygenated hemoglobin
Can be used to study very young infants
Could also contribute to the diagnosis and treatment of depression, schizophrenia and Alzheimer’s disease
Brain Scanning Techniques
MEG
(8)
Magnotoencephilography /mægnɛdoʊɛnsɛfəlagrəfi/
This is a new invention
Measures the very faint magnetic field that emanates from the head as a result of brain activity
This information is overlaid onto an MRI scan.
The process takes 1-4 hours (with breaks in between) and requires the subject to complete some simple tasks
This is accomplished by using magnetic detection coils bathed in liquid helium poised over a subject’s head
The liquid helium chills the coils to a superconducting temperature of -269ºC
The brain’s magnetic fields induces a current in the coils which creates a magnetic field in the SQUID
Brain Scanning Techniques
MEG
Cons
(4)
Costs millions of dollars
Weighs eight tons
Spacial resolution is not precise, but it’s better than an EEG
Information about deeper(subcortical) structures is less reliable
Brain Scanning Techniques
MEG
Pros
(5)
Provides the most accurate resolution of nerve cell timing (down to the millisecond)
Can show clearly where the brain activity is located.
Excellent time resolution (≤ 5ms)
It’s non-invasive
No injections
No dark, noisy tube
Nothing is stuck to head
Brain Scanning Techniques
MRI
(9)
Magnetic Resonance Imaging
Invented in 1977
The subject lies down on a moveable bed that is inserted into a giant magnet
It scans part of the body or the whole body
The magnetic field realigns the protons of the body’s hydrogen atoms so they all spin on the same axis. (They usually do not.)
This cancels out most of the hydrogen atoms, but a few are not.
The MRI machine sends a radio pulse of energy to the part of the body being scanned. This makes some of the uncanceled atoms spin at a particular frequency in a particular direction depending on the type of tissue
When the pulse stops, the atoms go back to their normal alignment which releases energy.
The MRI machine records this and processes these signals to produce an image of different tissues
Brain Scanning Techniques
MRI
Cons
(6+2)
Not great for emergencies - usually booked in advance
It is very expensive to operate
Uncomfortable for patients: claustrophobic, extremely loud, slow
The patient must remain immobile and children usually must be sedated
Very dangerous around metal
Flying metal objects can maim or kill patient
Metal in body can cause serious damage to patient
Brain Scanning Techniques
MRI
Pros
(4)
Machines do not emit radiation or require a radioactivetracer substance like a PET scan
Better spacial resolution
MRIs can show damage that is not visible on CT scans
These images can be done in cross-sectional “slices” if desired
Brain Scanning Techniques
PET
(12)
Position Emission Tomography
Developed in the 1970s
Currently, one of the most popular brain scan techniques in neuroscience
Observes blood flow/metabolism in any part of the brain (rCBF)
Radioactive glucose is introduced in the blood.
More radiation means more a higher glucose intake meaning more activity is happening
A PET scan is actually showing the levels of radiation in the brain
The computer uses the absorption data to create a color-coded brain map - the original data is in greyscale
Red usually indicates a high level or brain activity where blue tends to indicate a low level of brain activity.
Was originally only used for research purposes but now it is staring to be used for diagnoses
It can help doctors distinguish between cancerous tissue and tissue that is either dead or scarred
It is a promising way to diagnose Alzheimer’s Disease
Brain Scanning Techniques
PET
Cons
(5)
Exposure to radiation (although tiny)
Expensive
Very few machines available.
Poor time resolution (45 sec, Best time = 30 sec)
Not helpful in researching active brain function
Brain Scanning Techniques
PET
Pros
(3)
Allows researchers to
- Look at cross-sectional "slices" of the brain - Better spacial resolution - Observe deep brain structures
Brain Scanning Techniques
SPECT
Single Photon Emission Computerized Tomography
A type of PET
It’s much cheaper
“Poor Man’s PET”
Brainstem
4+4
Controls vital functions
- Breathing - Heartbeat - Blood pressure - Alertness
Damage to brainstem can lower your level of consciousness to such a degree that you can’t respond to anything
Critical to survival
This is one of worst places for brain tumors
Endothelia Cells
/ˌɛndə(ʊ)ˈθiːlɪəm/
(4)
Tightly packed cells that protects the blood vessels in the brain.
Important part of Blood Brain Barrier
Lets in the good stuff (like oxygen & glucose) but keeps out the bad stuff (like toxins)
Can be problematic when a doctor is trying to gain access to your brain in order to treat a neurological disease.
Ependymal Cell
/ɛˈpɛndɪmə/
Regulates Cerebrospinal Fluid
Satellite Cells
Offer physical support to neurons in the peripheral nervous system
Schwann Cells
Provide myelin to sheath neurons
One Schwann Cell can only sheath one axon
Cerebellum
4
“Little Brain”
Does not control all movement, but it kind of like movement “control central”
Involved in maintaining posture and balance
Smooths movements. If damage is sustained here, movements become exaggerated and jerky and balancing becomes difficult.
Cerebral Cortex
4
The surface of the cerebrum
It’s folded so we can have more cerebral cortex in that area
Composed of Brain Cell Bodies
Sometimes referred to as Grey Matter (because it looks grey when look at live brain tissue)
Cerebrospinal Fluid (CSF)
4+2
CSF is the clear salty liquid that your Brain floats in
It offers more support and protection for your Brain
It is continuously recycled which helps keep Brain clean
Without CSF your Brain would crush itself and cause Brain Damage. When you hit your head, CSF lets your brain float around instead of taking a direct hit
- The average Brain weighs about 3lbs - The average Brain in CSF weighs about 1.5 lbs
CSF Oterrhea
CSF leaking from the ears
CSF Rhinorrhea
CSF leaking into sinuses
Cerebrovascular Accident (CVA)
4
“A Stroke”
Condition where there is disruptive blood flow to the brain
Comprises 70% of all Neuropathology (meaning patients of Neurologist)
90% of all patients who have had a stroke will have lasting deficits
Types of CVA
4
Cerebral Hemorrhage
Cerebral Ischemia (Ischemic Stroke)
Thrombotic Stroke
Embolic Stroke
CVA Damage
3+3
Can be devastating depending on where the damage is and to what degree it is suffered
Clot damage happens very fast
- In 1 second = 32,000 neurons die - In 1 minute = 1.9 million neurons die - In 1 minute = 14 bill. synapses are lost
Damage can keep occurring days after the stroke has occurred.
Cerebrum
5
“Higher” Brain
Makes up 2/3 of total brain weight
Thinking part of brain
Contains both grey and white matter
Controls language, planning, thinking, etc.
Concussion
7
Caused by a direct blow or a force from shaking or whiplash
Can occur with both open and closed head injuries
Most common TBI
Brain’s blood vessels may stretch and cranial nerves suffer damage
Patient may lose consciousness or just feel “dazed”
Concussions may or may not show up on a CT scan
Can take a few months to a few years to heal
Contusion
3
Results from a direct impact
Bruise (bleeding) on the brain
Very large contusions may need to be surgically removed
Corpus Callosum
3
A bunch of nerve fibers
It’s pretty thick
Connects the left & right hemispheres of the brain
Global Deficits
Brain damage that affects everything
Dendrite
6
The nerve ending
Small branch-like projection
Connects and receives communications from other cells
Perceives environment
Can be located on one or both ends of neuron
Designed to increase surface area of neuron to allow for more input signals
Dorsal
Upper part
Dura Mater
7
Means “one tough mother”
Is tough and fiberous
Is the first layer of protection after the skull
Protects agains toxins & blood
Contains the entire brain
If the Dura Mater is not breached, then it can contain the brain even if skull cracked open
Top layer of the three Meninges
Edema
Swelling brain tissues compress against the skull
Galen
4
The brain is the seat of intelligence.
Brain kept the four humors in balance: Blood, Yellow Bile, Black Bile, & Phlegm.
Fan of autopsies and surgery (like brain surgery)
Used very precise tools for the time period.
Foundation of practices like bleeding.
Battle’s Sign Fracture
4
Skull is fractured a the ear’s Petrous Bone
Produces black and blue markings below ear, on jaw, and on neck
Can damage the auditory nerve
Blood and/or CSF can leak out of ears (CSF Oterrhea)
Basilar Skull Fracture
3
The skull is fractured at the base of the skull near the neck area
May include an opening
Can cause damage to the nerves and blood vessels that pass through this area
Compound Skull Fracture
The scalp is torn and the skull is fractured
Cribiform Plate Fracture
Cribiform Plate is thin structure behind the nose
If this is fractured, then CSF can leak through nose (CSF Rhinorrhea)
Depressed Skull Fracture
A broken piece of the skull moves in towards the brain
Diastatic Skull Fracture
Damage to the cranial sutures that hold the skull plates together in infants and young children
Racoon Eyes Fracture
4
Skull fracture is located in the anterior cranial fossa
Produces black and blue marks around the eyes
CSF may leak into sinuses (CSF Rhinorrhea)
Nerve damage can lead to a lack of smell or loss of eye function
Galvanometers
Instruments that detect and measure small amounts of electrical current
Franz Gall
6
(1758-1828)
Proposed that behavior and thought processes are localized to certain areas of the brain
This was considered revolutionary and insane.
Doctors, at the time, thought the brain was like the liver where the whole organ did mostly the same thing.
Proposed that the brain is like a muscle; brain areas grow and shrink with usage. This was the basis for the pseudoscience of Phrenology.
No one really knows how Gall derived the Phrenology map.
Glasgow Coma Scale
5+3
GCS
Gauges the neurological injury’s severity of the TBI
Can be mild, moderate, or severe
Gauges symptoms, not wound
Measured with three tests
- Eye Responses - Verbal Responses - Motor Responses
Glia
A type of brain cell that does not carry nerve impulses
The brain is composed of 90% glia cells and 10% neurons cells, but each makes up half the actual mass of the brain due to smallness of glia cells
Types of Glia
6
Astrocyte (Astroglia)
Microglia
Oligodendroglia
Satellite Cells
Schwann Cells
Ependymal Cells
Glioblastomas
Brain tumor that is much more dire
Hans Berger
An Austrian psychiatrist
Was the first person to record electrical activity in the brain
Four Layers of the Head
4
Skull
Cerebrospinal fluid (CSF)
Meninges
Brain
Epidural Hematoma
5
Bleeding between the Dura and the Skull. The Dura remains intact.
This also puts pressure on the brain but tends to be more fatal.
Usually when this occurs, a person is hit on the head and is knocked out. They seem to fully recover, but will later have an sudden onset of symptom.
These symptoms occur so suddenly that it is usually to late to treat the injury once the symptoms appears.
This is why brain scans are important when a potentially serious head injury occurs even if injured person seems ok.
Subdural Hematoma
3
Bleeding below the Dura (between the Dura and the Brain).
This causes the pressure of the blood to push on the brain tissue.
Brains are very delicate and cannot take that kind of pressure
Herpes Simplex Encephalitis
5+3
Affects particular lobes, usually the temporal and/or frontal
Survivors sometimes have no short term memory
Not all cases of herpes turns into Encephalitis
It is a dangerous disease because it presents as the flu. Patients are sent home without concern. Disease is usually not recognized until after severe cognitive symptoms appear. Usually by this point brain damage has already occurred
Often fatal
- 70% die without treatment - 25% die with treatment - 50% of survivors will have cognitive impairment
Hippocrates
5
The brain is the seat of intelligence.
Was very interested in the human body and how to help and cure people.
Was first person to discover that a brain injury on one side of the brain would cause paralysis on the other side of the body.
Fan of autopsies and surgery (like brain surgery)
Used very precise tools for the time period.
Hypertension
High Blood Pressure
Cardiocentric Hypotheses
The heart is the center of intellectual and perceptual functions
Inferior
Lower part
Ancient Egyptians & Brain Injury
4
Had strategies for assisting someone suffering from a brain injury
If someone suffered a split skull, they should be tied upright until the injury passes. This kept some people from bleeding out .
Some people would survive and improve.
Also know that drilling holes in someone’s skull sometimes helped them get better
Anoxic Brain Injury
Occurs when the brain is not supplied with oxygen
Anemic Anoxia
The brain does not receive enough oxygen
Anoxic Anoxia
No oxygen is supplied to the brain
Toxic Anoxia
Toxins or metabolites block the oxygen in the brain from being used
Closed Head Injuries
6
(CHI)
The skull remain intact
Some will distinguish CHIs by saying that the dura must remain intact
Causes Edema
When the brain swells, it has nowhere to spread
Sometimes it spreads into eye sockets causing damage to ocular nerves
Types of CHI
3
Coup Injury
Countrecoup Injury
Angular Acceleration
Countrecoup Injury
2+2
Occurs when the original blow causes the brain to hit the opposite side of the skull
Coup and Countrecoup Injuries can occur even without direct impact
Examples: - Whiplash - Shaken Baby
Coup Injury
The damage sustained is at the site of impact
It is caused by the compression of the skull on the brain
Hypoxic Brain Injury
Caused by the brain receiving some, but not enough, oxygen
Hypoxic Ischemic Brain Injury
Stagnant Hypoxia
Ischemic Insult
Caused by a critical reduction in blood flow to the brain
Or caused by low blood pressure that leads to a lack of blood flow to the brain
Penetrating Injury
10
Open Head Injury
Skull is fractured and the Dura is breached
Patient has a high risk for infection
Survival odds are great after the first day
Usually caused by projectiles
If an object goes “through-and-through”, there can be additional shearing, stretching, or rupturing of the brain tissue
Penetrating objects can ricochet in the skull causing even more damage
Firearms are the largest cause of Penetrating Injuries
Usually patient was in war, was attacked, or had a freak accident
Lesions tend to be focal. (Brain damage is localized to where the item went in)
Second Impact Brain Injury
Recurrent Traumatic Brain Injury
(4+5)
Occurs when a second brain injury is suffered before the first TBI has healed
More likely to cause brain swelling and widespread damage
Death can occur rapidly so emergency treatment is needed ASAP
Long term effects:
- Muscle spasms - Increased muscle tone - Rapidly changing emotions - Hallucinations - Difficulty thinking & learning
Traumatic Brain Injury (TBI)
2+2
People usually say Right TBI or Left TBI, but sometimes it’s just TBI, meaning that the whole brain is affected.
Of people who suffer TBI…
- 33% have language problems - 70+% have memory problems
Categories of TBI
Closed Head Injuries (CHI)
Open Head or Penetrating Injuries
High Risk Groups for TBI
5+2
Males 15-24 years
Substance abusers
Infants (64% abuse)
The elderly
- Issues with balance - Medications can affect equilibrium
Those who have had a prior brain injury
Mild TBI
2+12
GCS score of 13-15
Symptoms:
- Headache - Fatigue - Sleep disturbances - Irritability - Sensitivity to light or noise - Balance issues - Decreased concentration/attention - Decreased thought speed - Memory problems - Nausea - Depression & anxiety - Mood swings
Moderate TBI
4
GCS score of 8-12
Usually the patient had a loss of consciousness for a few minutes to a few hours
Confusion can last days to weeks
Physical, cognitive, and behavioral impairments can last months or be permanent
TBI
Recovery Tips
(6)
Rest
Don’t rush back to “normal”; take time to heal
Ask doctor before operating moving machinery (like cars)
Talk to doctor about any medications or drinking alcohol
Write down things you need to remember
You may need to relearn some skills
Severe TBI
3+6
GCS score below 8
Usually occurs with a prolonged state of unconsciousness for days, weeks, or months
Subgroups:
- Coma - Vegetative State - Persistent Vegetative State - Minimally Responsive State - Akinetic Mutism - Lock-In Syndrome
Jill Bolte Taylor
Brain researcher
She studied her own stroke as it happened
Is become a powerful voice for brain recovery.
Lateral
Toward the outside of the brain
Lateral Sulcus
Fissure of Sylvius
Is in left hemisphere
A neural loop that is important in understanding & producing written language
Broca’s Area is at the front and Wernicke’s at the opposite
Four Lobes of Cerebral Cortex
Frontal
Temporal
Parietal
Occipital
Frontal Lobe
4+6
Associated Functions:
- Emotions & emotional control - Motor planning & ability - Inhibition - Attention (Switching focus, etc.) - "Higher Order" thinking - All the extra stuff
Not memory, not language, but what you do with that information
Making sense of things
Occipital Lobe
Located at the back of your skull
Associated Functions:
- Visual Processing
Parietal Lobe
2+5
Located where a Yarmulke sits
Associated Functions (Are still being discovered!)
- Interacts with other lobes - esp occipital and temporal - Body awareness (recognizing your own body parts) - Sensory integration (matching visual info to what you already know) - Tactile processing (recognizing things by touch) - Spatial awareness
Temporal Lobe
3+5
Located behind the ears
Associated Functions:
- Auditory processing - Nonverbal processing - Processing music (recognizing something as a song) - Memory (storing individual memories) - Language
Amnesia often begins with damage here
Grey Matter
Cerebral Cortex
Medial
Towards the inside of the brain
Meninges
/mɪˈnɪndʒiːz/
(1+3)
Three layers that cover and protect the brain.
- Dura Mater
- Arachnoid
- Pia Mater
Meningiomas
/mɪˌnɪndʒɪˈəʊmə/
A tumor in the menages
Meningitis
6+4
Meningitis is swelling of the meninges
It can be caused by either a virus or by bacteria
The bacterial version is the most serious and deadly
It usually affects younger people
There is an available vaccination but it is so rare that most people do not get this.
It can be contagious but the carrier is not always affected.
Symptoms:
- Stiff neck - Inability to bring chin down to neck - Fever - Headache
Microglia
Digest parts of dead neurons
“Zombie-glia”
Microtubules
Kind of like the neuron’s skeleton
Helps transport some things up and down the axon
Myelin Sheath
3
Protects/insulates the Axon
Composed of fat and protein
Speeds up the transmission of the nerve impulse
Myelinated Neuron
Found in peripheral nerves
Parts of a Neuron
11
Dendrite Soma Axon Hillock Axon Myelin Sheath Nodes of Ranvier Axon Collateral Microtubles Axon Terminals Axonal Varicosities Synapses
Non-Myelinated Neurons
Found mostly in the brain and the spinal cord
Neuroimaging Techniques for Examining Brain Activity
Direct Measurement of Neural Activity
(2)
EEG
MEG
Neuroimaging Techniques for Examining Brain Activity
Indirect Measurement of Neural Activity
(1+3)
These techniques measure neural activity via something else
PET
fMRI
fNIR/DOI
Neuroimaging Techniques for Examining Brain Structure
2
CT/CAT
MRI
Neuroplasticity
3
The concept that after brain damage, brain pathways can change and many people recover mental functions.
Why do some stroke victims have more neuroplasticity than others? This is a issue we are currently studying.
Neuroplasticity decreases during and after adolescence. Young people are able to reorganize their brain pathways vastly better than adults.
Neuroscience in the 1800s
3
Still drilling holes but with more sophisticated tools.
Infection was a major risk factor.
Still did not have a great understanding of brain function
Interactive Approach to Neuroscience
3
Is becoming more vocal as research is becoming dominated by the modular approach.
Believe that mental processes involve interaction among many brain areas.
Areas highlighted in brain scans are so closely interconnected that a process cannot be localized to just one area, so these could be junction centers and not isolated processes
Evidence for the Interactive Approach to Neuroscience
3
Neurons are interconnected. There are no clear boundaries between sections.
After brain damage, brain pathways can change and many people recover mental functions. (Neuroplasticity)
Under the Modular Approach, this shouldn’t happen as often as it does.
Modular/Localist Approach to Neuroscience
3
Assumes brain areas are highly specialized for specific mental abilities.
Believes that, through carefully study, we will eventually be able to create a detailed “brain map” of all mental processes.
Believes that, although other parts of your brain can compensate for a damaged area, the new area will not be able to function as well as the intended area.
Evidence for the Modular/Localist Approach to Neuroscience
There is a strong relationship between specific brain areas and resulting deficits (ex., left hemisphere damage usually results in language deficits.)
Neuroimaging researchers show evidence that cognitive processes can be localized to specific areas
Neurotransmitter
3
NT
Type of chemical
Crosses Synapse, attaches to ends of dendrites, & is converted to an electrochemical signal (nerve impulse)
Nerve Impulse
An electrical current that travels along dendrites or axons
Peripheral Nervous System
The Sensory Nervous System & the Motor Nervous System
Nodes of Ranvier
Gaps in the myelin sheath
Oligodendroglia
/ˌɒlɪgə(ʊ)dɛndrəˈglʌɪə/
Provide myelin to sheath neurons
One oligodendroglia cell can sheath more than one axon
Optic Chasm
The place where half of your optic nerves cross into the opposite hemisphere
Phineas Gage
9
Most famous open head injury case
Gage suffered his injury in the 1800s
He was a railroad foreman
Forgot to first pour in sand to insulate the explosive. Instead he hit the explosive directly with his Tamping Iron (a large iron rod)
The explosive ignited and the tamping rod shot into his head and all the way through
Gage lost the use of one eye and had personality and emotional changes due to frontal lobe damage
People now suspect that he played up many of his emotional changes
This caused doctors to begin to make the connection between the frontal lobe and our emotions
He became a side show in a traveling circus and became very attached to the rod and was buried with it
Phrenology
5
Based on the idea that brain areas grow and shrink with usage, so the skull will have bumps and valleys based on the shape of the brain underneath.
Phrenology was all the rage in the United States during the 1930s
Someone even created a psychograph or a machine that automatically read your phrenology.
Phrenology was debunked by Mark Twain.
Phrenology relates somewhat to the current debate of whether or not mental abilities are localized to certain areas of the brain
Pia Mater
7
Means “tender mother”
It is so thin that you can barely see it.
It actually adheres to brain.
Very delicate and easy to rip
High vascular (meaning it contains a lot of blood vessels)
Its job is to supply blood to brain tissue
Last layer of the three Meninges
Posterior
Toward the back
Skull
4
Extremely strong & flexible
Not totally smooth. There are boney projections that hold the brain in place.
The brain is floating in fluid. If the brain were to sit flat in the skull, then the bottom would be damaged.
The brain’s design offers great protection for a primitive world. Our modern world adds more dangerous elements.
Smiles
3
A natural smile is produced by lower brains. This is automatic and does not involve the cerebral cortex.
“Picture Smiles” are generated by your higher brains (cerebral cortex)
Someone with stroke damage to their right motor cortex will only be able to make a half smile when requested to smile, but can generate an almost perfect smile when they see someone they love or something gladdens them.
Soma
1+4
The cell body
Contains all necessary cell parts
- Nucleus - DNA - Endoplasmic reticulum & Ribosomes (building particules) - Mitochondria (makes energy)
SQUID
Superconducting Quantum Interference Devise
An extremely sensitive instrument that measures extremely subtle magnetic fields
Cerebral Hemorrhage
Hemorrhagic Stroke
(6)
More likely to occur in young people
Caused by a cerebral blood vessel breaking
This causes blood flow to be interrupted
The blood hemorrhaging will irritate & damage the surrounding neurons
This means the BBB is not being used and the neurons are now also getting all the bad stuff too
Hemorrhages can result from an aneurysm bursting or long standing high blood pressue
Intracerebral Hermorrhage
Bleeding occurs from blood vessels within the brain itself
Usually caused by hypertension
Subarachnoid Hemorrhage
3
Aneurysm bursts in a large artery on or near the arachnoid
Blood hemorrhages into the area surrounding the brain
Causes blood contamination
Embolic Stroke
5
Caused by a traveling clot.
This clot will start somewhere like the heart then travel to a brain artery and get stuck
These strokes have a rapid onset of symptoms
It is an emergency situation when someone suddenly can’t move half their body, can’t talk, etc.
If their face is the only thing affected, then it will probably be Bell’s palsy - not a stroke. Bell’s Palsy is temporary.
Cerebral Ischemia
Ischemic Stroke
(3)
A cerebral artery to the brain is blocked
Causes 80% of all strokes
The clot blocks blood from reaching an entire section of the brain which can cause tremendous damage
Types of Ischemic Stroke
2
Embolic Stroke
Thrombotic Stroke
Thrombotic Stroke
5
Caused by a clot forming in a narrowed blood vessel
This may occur slowly over time
Often there is a gradual progression of symptoms
They symptoms are usually not noticed by the child living nearby, but by the child who lives further away who comes to visit who notices a drastic change
Thrombotic Strokes may be proceeded by Transient Ischemic Attacks (TIAs)
Large Vessel Thrombosis
3
More common and better understood
A slow forming clot is followed by rapid blood clot formation
These patients usually have coronary artery disease and usually die from a heart attack, not stroke
Small Vessel Thrombosis
Blood flow is blocked to a very small artery
Seems linked to hypertension
“Subcortical” Areas
4
Areas below the cortex
Made up of Axons and their Myelin Sheath
This is referred to as White Matter
Cortical dementia attacks the grey matter / Subcortical disorders attack white matter
Superior
Upper part
Locked-In Syndrome
4
Rare neurological condition
Person cannot move anything physically except their eyes and eyelids
Person is conscious and can think
Vertical eye movements and blinking is used to communicate with others and to operate environmental controls
Shaken Baby Syndrome
6+4+6
Caused by aggressively shaking a baby or small child
Requires immediate medical attention
The blood vessels between the skull and the brain rupture and bleed
Pressure builds from the bleeding while the brain swells due to injury
Long term effects:
- Seizures - Life Long Disabilities - Coma - Death
Signs:
- Changes in eating patterns - Tiredness - Difficulty breathing - Dilated Pupils - Seizures - Vomiting
Synapse
The space between the dendrite of one neuron and the axon terminal of another
Trepanning
4
The surgical procedure of scraping, chiseling, or cutting the skull to expose the brain.
Evidence of this practice exists as early as 5100 B.C.
Practiced by Aztecs
Proof that, very early on, humans knew something was important with the brain and messing with it could be beneficial (or not?)
Transient Ischemic Attacks (TIAs)
3
These can look like the scary (Ischemic) strokes, but they are transient (temporary)
There will be a blockage which will cause stroke symptoms, however the blood pressure will cause blockage to pass and the person will recover
This is usually what gets people to visit the neurologist and be able to be diagnosed
Ventral
Lower part
Tumors
Benign tumors can still cause brain damage since your brain is delicate and cannot take the pressure
Brain surgery often has to remove some healthy brain cells to make sure they remove all cancer cells. This can cause deficits. Surgeons often do brain mapping before surgury but this can be skipped if patient will die unless tumor is removed.
White Matter
Subcortical Areas
10 Brain Myths
The brain is grey
Listening to Mozart Makes You Smarter
You Get New Brain Wrinkles When You Learn Something
You Can Learn Through Subliminal Messages
The Human Brain Is the Biggest Brain
Your Brain Stays Active After You Get Decapitated
Brain Damage Is Always Permanent
You Can Get Holes in Your Brain Through Drug Use
Alcohol Kills Brain Cells
You Only Use 10 Percent of Your Brain
