1. Brain Damage daguerreotype The Boston Post for September 21, 1848
Phineas P. Gage
(July , 1823 – May 21, 1860)
1st case widely cited in medicine to infer that brain function can alter personality

2. ~1850
Pattern of injury is very localized
-blood vessels spared
- only frontal cortex damaged
- loss of 1 eye
Consciousness regained in days
- personality/behavior dramatically altered
- child-like, profane, disinhibited, inappropriate, inability to control anger and other
emotions.
Referred to today as classic “hypofrontality”
-common with traumatic injury to the frontal lobes
Until 2008, commonly thought that he demonstrated these symptoms until his death, 12 years later. But this was not true…
“Social Recovery”

3. Traumatic brain injury Strokes Alzheimer’s Disease Parkinson’s Disease
Brain Damage
Traumatic brain injury
Strokes
Alzheimer’s Disease
Parkinson’s Disease
Other neurological disorders discussed in the book will
NOT be subject to test questions

4. Traumatic Brain Injury
FACTS:
1.4 million who sustain a TBI each year in the United States (0.5% of people in U.S.)
50,000 die;
235,000 are hospitalized; and
1.1 million are treated and released from an emergency department.
What causes TBI?
Falls (28%)
Motor vehicle-traffic crashes (20%)
Struck by/against (19%)
Assaults (11%)
Who is at highest risk for TBI?
Males are about 1.5 times as likely as females to sustain a TBI.1
The two age groups at highest risk for TBI are 0 to 4 year olds and 15 to 19 year olds
Certain military duties (e.g., paratrooper) increase the risk of sustaining a TBI
Langlois JA (2006)

5. Types of Traumatic Brain Injury
“Closed Head Injury”
Concussion. Concussions are the most common type of TBI. A concussion is damage to nerves or blood vessels in the brain often caused by an impact to the head.
Contusions. A contusion is a bruise or bleeding on the brain that can be caused by an impact.
Diffuse Axonal Injury. This is tearing of nerve tissue or blood vessels when the brain is jostled in the skull. It can result from shaking (for instance, shaken baby syndrome) or whiplash
Coup-countrecoup Injury. impact not only injures the site of impact, but causes the brain to impact with the skull, causing injury to the opposite side of the brain.
Symptoms:
acute: confusion, visual disturbance, unconsciousness if severe
long-term: memory problems, sensory problems .
- “dementia pugalistica”

6. How does traumatic brain injury develop ?
direct, mechanical injury to neurons (axons, dendrites or soma)
damage to blood supply deprives neurons and glia of nutrients
Overactivity of glutamate receptors
Activation of NMDA-type glutamate receptors
Inflow of too much Ca2+ into neurons
activates death enzymes that break down neuron
Impairs neuron ability to meet energy requirements
Triggers cell death
A little bit of Ca2+ inflow is good at the right time, too much is toxic

7. disruption of blood flow in brain
Strokes
disruption of blood flow in brain
3rd leading cause of death in adults
Hemorrhage: bleeding in brain, blood vessel ruptures
- can be from traumatic injury to blood vessel
- can be from “aneurysm”
weakening of blood vessel wall, balloonlike
dialation forms and can burst
caused by some infections, toxins like cigarette
Smoke. Can also be develomental abnormality.

8. How does a loss of blood supply kill neurons ?
2. Ischemia: blood flow to a brain region is blocked
- a blockage that comes from another part
of the body is an “embolism” (vs. thrombosis)
for example, a blood clot in leg, can travel to brain
and cause ischemia is gets stuck in a smaller artery.
“arteriosclerosis”: fat deposits in brain blood vessels grow
over time and block blood flow. (can become embolism)
How does a loss of blood supply kill neurons ?
-deprived neurons become overexcited, release glutamate
-glutamate activates NMDA receptors
- and because no blood supply=no energy, no reuptake of glutamate

9. Dementias instability What causes dementia ?? 12-15% stroke
deterioration of intellectual abilities due to disease
*memory, judgment, concentration
*usually w/ personality changes, emotional
instability
What causes dementia ??
12-15% stroke
12-15% Huntingtons, Parkinson’s Diseases (motor diseases)
* other similar disease that are rare
>5% Korsakoff’s syndrome
severe anterograde amnesia
Alzheimer’s Disease (leading cause of severe dementia in U.S.)
- +1% of population, most over 65 yrs old

10. neurons in several brain regions.
The severity and type of symptoms observed is directly related to death of
neurons in several brain regions.

11. But, we know that…: Causes ?
We do NOT know what causes Alzheimer’s Disease !
But, we know that…:
Risk of developing it is heritable
there is a “genetic” factor involved
2. Some AD patients have a specific genetic problem
That can cause early-onset and severe form (~45 yrs old)
3. But, many other AD patients don’t have family members
with AD and don’t have an identified genetic problem
Alzheimer’s Disease is probably just 1 term used to describe
the symptoms of lots of different diseases that cause
brain damage and similar symptoms.

12. I. Plaques: most AD patients have plaques in
parts of the brain that show cell loss
in early AD: medial temporal lobe areas
(hippocampus) and cortex
in late AD: lots of areas
(all areas that produce or receive acetylcholine)
Plaques are made of a protein called beta-amyloid
2. Beta amyloid come from a normal protein that neurons need to function normally,
called Amyloid Precursor Protein (APP)
3. but, APP is cut by enzymes into abnormal amounts of beta amyloid.
-neurons can get rid of a small amount of beta amyloid, but
if there is too much, beta amyloid clumps together to form plaques inside of neurons.
Neurons don’t function normally and die-off
Key to understanding plaques:

13. II. Tangles: Many AD patients also have “tangles” in neurons
Microtubules are long string-like structures that transport
things from the cell body to the end of the axon and dendrites
Tau proteins (like rungs of a ladder)
In AD, these microtubules break apart and
collapse into a tangles mess and neurons don’t function normally,
so they die-off.

14. Gross Pathology: Ventricles larger gray matter loss white matter loss
Normal Human
Gross Pathology:
Ventricles larger
gray matter loss
white matter loss
Human with Alzheimer’s Disease

15. Drug Treatment of Dementias
Drugs approved by the U.S. Food and Drug Administration
Cognex®
Aricept®
Reminyl®
Exelon®
Namenda®
YOU DON’T NEED TO KNOW THESE
All are inhibitors of acetylcholinesterase, except Namenda
Acetylcholine is release from “presynaptic” neuron, and then re-absorbed
lots of it in hippocampus and cortex
2. Acetylcholinesterase is an enzyme that breaks down acetylcholine
3. That means that more acetylcholine is present in synaptic cleft to stimulate
receptors on neurons in learning/memory areas

16. Key facts about acetylcholinesterase inhibitors:
some improvement in daily living skills
some delay in progression of disease
BUT, typically a small effect and occurs in a small % of patients
Can be very toxic to the liver
Namenda® FDA approved to treat late-stage Alzheimer’s
the newest approved drug (2004)
Namenda® - blocks the NMDA receptor for a very short period of time
Based on theory that over activity of NMDA receptors contribute
to neuron death in Alzheimer’s disease
Does it work ?: small effects in a small # of patients
But, these small effects have a dramatic effect on quality of life

17. Parkinson’s Disease
mentioned in the Ayurveda, the system of medicine practiced in India as early 7,000 years ago , and in the first Chinese medical text, Nei Jing, which appeared 2500 years ago
"An Essay on the Shaking Palsy," published in 1817 by a London physician named James Parkinson,

18. Symptoms Difficulty initiating movement Shuffling gait
“Cogwheel” rigidity
Tremor at rest
Advanced stages may include psychiatric complications
depression
hallucinations
Paranoia
Cognitive decline

19. Incidence Onset usually appears after age of 40 years
but can begin at any time including childhood when it is termed juvenile parkinsonism
affects 1% aged 50 years and over
10% aged 60 years and over may have undiagnosed, early stages of the disease
about 1½ times more common in men than in women

20. Subtypes Primary (idiopathic- most common) Secondary (parkinsonism)
unknown origin but not induced by obvious stimulus
Secondary (parkinsonism)
related to drugs, stroke, or trauma, other stimuli
Familial
genetically linked
accounts for < 20% of the diagnosed cases

21. Progression: identified too late ?
Considerable dopamine loss must occur before the disease is apparent
clinical diagnosis is usually made after  80% loss in basal ganglia dopamine content
symptoms may emerge after a 60% reduction in basal ganglia dopamine content
The disease is probably present > 20 years before diagnosis

22. Meso-Striatal Dopamine system
COMPONENTS OF THIS SYSTEM
Substantia Nigra- in midbrain
- send fibers to Basal Ganglia
- releases dopamine = movement
Basal Ganglia (part of striatum)-
-sends fibers to motor cortex
-receives fibers from sensory
cortex and substantia Nigra
In Parkinson’s Disease
Substantia Nigra neurons die = reduced excitatory input into basal ganglia
The two parts of the basal ganglia (Caudate and Putamen) also die

23. Postmortem Analysis Shrunken Substantia Nigra
brain photographs courtesy of the University of Utah Medical School
Roberta J. Seidman, M.D., SUNY
Shrunken Substantia Nigra

24. Loss of cellular activity in the Basal Ganglia
PET Scan
Loss of cellular activity in the Basal Ganglia

25. Pathology in Parkinson’s Disease
Lewy body pathology: these bodies are circular structures
found in cytoplasm.
Dense core of protein called α-synuclein
- normally aids in synaptic vesicle function
Abnormality in gene that makes this protein is a
significant risk for Parkinson’s disease
Many environmental toxins lead to clumping of
α-synuclein too (pesticides, drugs of abuse ?)

26. Parkin abnormalities ? (familial PD)
gene mutation that is a risk factor for Parkinson’s Disease
Parkin: a protein found in neurons that transport abnormal proteins
to a “proteosome” and tag these proteins with a “death flag”
called “ubiquitin”.
“Ubiquitination” of a protein signals the proteosome to degrade the
protein into its amino acid subparts.
Overactivity of Parkin in brain regions controlling motor function can
cause over-activation of the proteosome
neuronal death

27. Treatment Levodopa (L-dopa) therapy (L-dopa is a dopamine precursor)
generally very effective for the first 2 to 5 years of treatment after which the on-off effect develops
Direct-acting dopamine receptor agonists
Experimental brain surgery
lesions of nuclei that inhibit basal ganglia
- remove inhibition of dying neurons, they may be more active = motor control
neural tissue implants (e.g., fetal dopamine cells)

28. Substantia nigra cells were surgically implanted into the right putamen. Note the continued degeneration seen on the contralateral (left) side revealed by the PET.
Recently, Deep Brain stimulation - indwelling electrodes implanted in some of the dying neurons. Patients can stimulate electrodes , provides a brief pulse to these neurons, which rapidly restores some control of motor activity.
PET images courtesy of the UCLA School of Medicine, Division of Brain Mapping