Proliferation; the stem cells lining neural tube gives rise to the primitive ____ and ___?
These primitive/immature neurons and glia begin to migrate while the stem cells rapidly continue to produce more ____ neurons & __ cells?
a: neurons b: glia c: baby D: glia
Migration = movement of ____ & ____?
neurons & glia
Differentiation: immature neurons develop ___ first? A neuron may grow it's axon by initially locating near the ____ and growing the axon ___ from the target cell?
a: target b: away
Differentiation: can leave the tip of the axon ____ the target Or it may grow the axon ___ toward the target?
a: near b: down
Myelination is the process by which glial cell form ___? Myelination continues for ___? think how long it takes for your legs to finish growing...
a: myelin b: decades
A mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibers, increasing the speed at which impulses are conducted =
Synaptogenesis =? and begins before birth, and continues through ___? and slows with age as do formation of new ____ branches?
a: formation of synapses b: life
Most neurons develop by _____?
infancy *very few grow afterwards
WE continue to have __ cells in the ___ receptors?
a: stem b: olfactory
Birds develop ___ each spring for singing?
As neurons grow older, they are less capable of changing _____ shape and making new ____?
a: dendtrites b: connections
Possible stem cells in the ___ will stay to help keep this area able to learn new tasks
It appears that in mammals, at maturity, the ____ cortex forms few or no new neurons under normal circumstances
Carbon 14 study showed that c-14 peaked in 1963 has been ____ since that time?
Cells keep their DNA until ___?
Skin cells change every ___? so the c-14 level in skin cell DNA is the same as the year you're testing
Heart cells aren't replaced (maybe 1% a year) and the C-14 level in their DNA corresponds to the ____?
year of birth
C-14 study show that levels in neurons in the cerebral cortex correspond to the year of one's __?
Chemical (guidance cues) that proteins in the axons are attracted to, guide neural migration and are responsible for ___ getting to their target cells
Axons form many connections in approximately the ____ location and dendrites(target cells) ____ synapses from many axons?
a: correct b: receive
Over time some synapses are ___ and others are ___?
strengthened and eliminated
Neural Darwanism- synapses form with only approximate accuracy and then a selection process occurs and we ___ some & ___ some
keep & reject
When a neuron synapses onto a target cell, the target cell releases a protein called ___? that allows the neuron to survive
Nerve Growth Factor (NGF)
If the axon does not connect with the appropriate post-synaptic cell by a certain age, the neuron ____? This self-distruction is called ___?
A: degenerates b: apoptosis
When a Neuron dies because of injury =
Nerv Growth factor(NGF) is a ____ found in the CNS
a: neurotrophin * greek for nourishment
Neurotrophins are a family of ___ that promote neuron survival and development.
Belong to a class of growth factors(proteins the that signal particular cells to ___?
a: protiens b: survive
Brain-derived neurotropic factors (BDNF) is a neurotropin necessary for the growth of ___ & ___, and formation of new ____?
a: axons & dendtrites B: synapses
For an immature neuron to survive it needs ____ from target cells and ____ from incoming axons, so they need connections at both ends
a: neurotrphins b: neurotransmitters
All areas of the nervous system make more neurons than needed. The developing muscle doesn't know exactly how big a muscle, ___ will be
Brain areas of a period of massive cell death that is required for ______?
E.g., teens show increased activity in their frontal lobes during a time when they are losing cells in that area. * maturation of needed cells is linked to ___?
loss of non-successfully linked cells
People who are born blind have a thicker ____ than sighted people =
a: visual cortex b: = ineffective "pruning"
Developing brain is very sensitive to ____, ____, & infections?
Fetal alcohol syndrom- alcohol crosses the placenta where it is neuro-toxic and can cause permanent damage to the__?
Effects of Fetal A-Syndrom are?
attention deficits, cognitive impairment, memory, learning disabilities, motor problems, poor awareness, facial and heart abnormalities
Fetal A-syndrom is known as the leading cause of ___ in the US and Europe.
3 cases per 1000 births in Native americans
cognitive impairment/mental retardation
Fetal A-syndrom causes?
impairments in learning, memory, language and attention
There is no safe consumption of alcohol during pregnancy
Neurons need neurtrophins from both the target cell and from ____ connecting to the neuron(a neurrotransmitter)
Alcohol is a glutamate _____ and a GABA ____, so it blocks the main excitatory NT and stimulates the main inhibitory NT.
a: antagonist/inhibitor b: agonist
Alcohol causes neurons to receive less ____ and consequently the developing neuron dies
decreases or stops completely
Agonistic drugs are those that work to...
mimic or enhance the effect of a neurotransmitter in the brain
Antagonistic drugs work by blocking
neurotransmitters in the brain
Nicotine is a direct-binding agonist for Acetylcholine receptors --acts just like a neutrotransmitter, so the user feels the same effects as he or she would feel if a large amount of dopamine were to be released in the brain
Cocaine is an example of an indirect-acting agonist in the dopamine system -and thus enhance its action
Antagonistic drugs also come in two main forms. Direct-acting and indirect-acting antagonist
Direct-acting antagonists bind to the same receptor area as neutrostransmitters and block the neutrotransmitters themselves from binding to their receptors
B. indirect-acting antagonist drug works by inhibiting the production or release of neurotransmitters
Axons and Dendrites modify their structure throughout life.
Gain or loss of dendritic spines relates to?
Rats in an enriched environment show
better development of dendtrites and axons
Far Transfer- the idea that intellectual stimulation in one area will cause one to be more...?
intellectually capable in other areas
Far transfer is difficult to demonstrate for E.g...
its hard to say if people who are more mentally alert don't just choose to do puzzles more often
Far transfer doesn't help someone where to remember where you parked your car only that you're better at word puzzles
also, practicing one task does not make one better at at a very similar task
Best ways to maintain healthy cognitive function into old age are...
physical activity, practice/repitition,
Losing a sense does not affect other sense receptors for e.g..
blindness does not change the touch receptors or change the receptors in the area for hearing
people who lose a sense, the other senses adapt and become more ?
enhanced and sensible
In blind people, there is substantial activity in the ____ cortex when presented with either touch or auditory sensations
occipital --- info from those senses has invaded teh visual cortex which normally only processes visual info
When occipital cortex of blind and sighted people where inactivated by magnets, blind, but no sighted people, did worse at?
identifying objects they were feeling
Blind people also outperform sighted people on many verbal skills.
is also linked to activity in the occipital cortex
When a brief magnetic stimulation was applied to sighted people at the occipital cortex, they report a ?
a flash of light, but blind people saw very little or almost nothing due to neuron damage in that area
Gray matter of areas in the brain related to hand-control and vision are ____ in musicians than non-musicians
also practicing a skill re-organizes the brain to maximize performance of that skill
If the representation of the fingers grows from side to side without spreading out the areas representing that finger can --? overlap a
When reorganization occurs, stimulation of one finger ___ the same ___ areas of another finger
a: excites b: cortical
"Musicians cramp" =
focal hand dystonia, the fingers become clumsy, tired, move involuntary
Extensive reorganization at the level of the ___ and ___?
thalumus and motor cortex
Ati-saccade task =
looking away from a powerful attention getter, almost impossible for kids age 5 & younger
a: voluntary eye movement
b: voluntary movement away from normal dirrection
Studies show that adolsescent brains have strong responses when anticipating rewards and ____ responses in areas ____?
a. weak b: responsible for inhibiting behavior
In general people see decline in memory at what age?
with age, neurons ______ more slowly, Temporal cortex and hyppocampus becomes ____?
a:alter synapses b: thinner
** around age 30 frontal cortex begins thinning
How do older brains compensate for loss of memory?
* both sides of the prefrontal cortex were activated and only one side for the same task were shown for adolescents...
* older adults use multiple parts of the brain to compesate
Traumatic brain Injury also TBI
injury to the brain by external forces, caused by direct impact or acceleration injury-movement of brain in the skull
What causes damage to neurons?
-direct crushing-shearing of axons-high concentration of glutamate transmitters
TBI- Primary impact followed by a secondary injury - e.g.,
bleeding, blood clots interrupting, inflammation, increased pressure in skull
Main causes of TBI are?
Falls, esp. ages 2-4, abuse 20%, car accidents, construction accidents, sports, fire arms, and blast injuries-1.4 million a year USA only, 50 k deaths
Chronic Traumatic Encephalopathy -CTE
A degenerative disease due to multiple concussions-"punch drunk" - early boxers in 1920's
Ann McKee, MD- found a link between head trauma and long-term degenerative brain disease
-mainly football players of young to old ages and some veterans - 80% showed CTE
CTE- Atrophy of frontal and frontal Lobes
-also of the thalamus, brainstem, substantia nigra, cerebellum-neural loss, protein deposition (Tau Protein) neurofibrially tangles and glia tangles
Tau Protein =
"glue" that holds microtubules together, when neurons are damaged these proteins tangle - similar to alzheimers DZ
4 progressive stages of Chronic Traumatic Encephalopathy- symptoms
4. deterioration to dementia, increased inability to walk, talk, -aggression builds up
CTE - NFL players who died of multiple cuncussions
-Dave Duerson-suicide-stage 3 cte
Multiple concussion within same week =
far more dangerous than if had them independently
Study for TBI in rats showed....?
-decreased glucose metabolism at 24 hrs (19%) in parietal lobe and hippocampus
-2nd tbi = 37% decrease in glucose in 24rs and 25% in 3 days
--** damage is additive
Cerebrovascular Accident (CVA) aka "stroke"
-interruption of normal blood flow, lacking O2
2 types of of CVA's are?
Ischemic & hemorrhagic
Ischemic CVA are caused by ?
-blockage in a artery
Hemorrhagic is caused by?
ruptured blood vessel bleeding into brain
CVA-stroke - symptoms
-unsteady gate, trouble speaking or understanding, paralysis of motor cortex, weakness or numbness of part the body on one side, sudden visual changes, heachache.
-Go to ER immediately
CVA/Stroke- time is crucial for treatment
-get CT scan to see if it's hemorrhagic or ischemic
-if ISCHEMIC - RX = tissue plasminogen activator (TPA) dissolves blood clots.. the sooner the better
Ischemic---> lack of blood---> lack of O2, and glucose and therefore lack ATP
so no Na+/K+ pump, but High levels of NA+-- neuron death---release glutamate--toxic
-edema increases the pressure on surrounding neurons and increases additional strokes
CVA/stroke--- Which Glia cells proliferate and migrate to stroke area to help "clean up" dead cells and supply chemicals to help remaining neurons survive
-cool the brain down, keeping neurons from releasing glutamate
-stimulant drugs, study with drugs... showed improvement once off the stimulant drugs
After damage in any brain area, other areas that have lost part of their normal input become less active
-So you will see deficits in areas that haven't been damaged
-Possible treatment- stimulate the areas that have lost input but are still intact themselves
Regrowth of Axons - destroyed cell bodies are not replaceable but when axons are damaged they can grow under certain circumstances
- in the Peripheral Nervous System-if crushed, an axon can grow back following it's myelin sheath (Schwan cells.) if the axon is cut, it may or nmay not line up correctly and the axon may not follow the correct path
Mammals form scars after axon damage- this provides initial support for other neurons in the area but then?
Which glial cell is responsible for most scar formation?
with neuron/axon damage some of the chemicals released during damage ___?
Regrowth of Axons?
-possible protein bridge for axon to travel to bypass scar
-injecting neurotrophins to help with growth and synapse formation
What creates new synapses?
after a target cell loses input from an axon, it secretes neurotrphins that induce other axons to form new branches(collateral sprouts)-- good or bad depending if it brings different NT's
gamma-amino-butyric acid = GABA
When brain experiences an abundance of nervous tension and stress, it can be caused by a surplus of norepinephrine or epinephrine (adrenaline). To neutralize this extra adrenaline, the brain produces neurotransmitters, one of which is GABA, that have inhibitory effects upon the nervous system.
GABA is synthesized in the brain from another amino acid, glutamate and....
functions as an inhibitory neurotransmitter – meaning that it blocks nerve impulses. In the body, GABA is concentrated in the hypothalamus plays a role in the overall functioning of the pituitary gland – which regulates growth hormone synthesis, sleep cycles, and body temperature.
A simplification of GABA is this.
Our bodies are in a constant "on" state because of constant nerve impulses. Without GABA's causing an occasional "off" state their would be no resting state. Our metabolic rate would increase to a non-functional point.
In a developing brain GABA is an exicatory neurotransmitter until the glutamate synapses fully matures.
If a number of axons die, the remaining synapses become more sensitive
Reorganized sensory representation/phantom limbs
if a brain loses a set of incoming axons, e.g, an arm one would expect increased sensitivity at the target cells(denervation) and collateral sprouting by other axons that normally attached to some other target
Moneky finger amputation
the 3rd finger was cut, the cortical area that was responsive to that finger, became more responsive to fingers 2 and 4
Phantom limbs sensations occur if the protein of the extrasensory cortex that had been receiving sensory input from the now missing limb,....
reorganizes and becomes responsive to axons that have sprouted from other areas of the brain
Phantom Lms: axons that carry info from other areas (shoulder), sprout new ___ and the synapse to the area of the ____
a: axons b: somatosensory cortex that use to receive sensory info form the hand
Phantom L: now the area of the brain that use to get info from the hand get info from the___?
Phantom-Limbs: A touch to the shoulder feels like it is coming from the ___?
missing body part
Amputees who learn to use an artificial limb generally experience ____ "phantom" sensations
Sensations from the area that attaches to the artificial limb, ____ the abnormal connections
displaces = replaces
Therapy after brain damage focuses on ____?
practicing skills that may be impaired but aren't lost
Broca's area is one of the main areas of the cerebral cortex responsible for producing language
This brain area controls motor functions involved with speech production. Persons with damage to Broca's area of the brain can understand language but cannot properly form words or produce speech
Wernicke's area is associated with processing and understanding language.
Therapists can help patients with damaged brain areas (PT, OT, etc..)
the sooner you start practicing after damage the better
Iron Mike webster- movie notes-- suffered multiple brain injuries... concussions and etc...