Term
| What are our primary senses? |
|
Definition
- audition
- vision
- olfaction
- taste
- smell |
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Term
|
Definition
| conversion of physical energy from the environment into changes in electrical potential |
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Term
|
Definition
| Making sense of that input |
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Term
What is transduced?
vision |
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Definition
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Term
|
Definition
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Term
What is transduced?
hearing |
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Definition
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Term
|
Definition
| pressure, temperature changes |
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Term
|
Definition
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Term
What are the cells responsible for transduction?
vision |
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Definition
|
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Term
What are the cells responsible for transduction?
taste |
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Definition
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Term
What are the cells responsible for transduction?
hearing |
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Definition
| hair cells in inner ear (cochlea) |
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Term
What are the cells responsible for transduction?
touch |
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Definition
| specialized receptors under skin |
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Term
What are the cells responsible for transduction?
smell |
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Definition
| hair cells in olfactory epithelium |
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Term
| General pathway for most sensory |
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Definition
1) sensory neurons – sensory nerves
a) spinal tracts
i) thalamus
- primary cortex
- higher association cortex |
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Term
|
Definition
- Certain sensory neurons have a spontaneous firing rate
- For these cells any change in their firing rate will convey important info (i.e. color vision)
- Different rhythms of firing also can convey different information |
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Term
|
Definition
1) most highly developed sense in humans
2) adaptability and plasticity of visual system (make sense out of nonsense)
3) 1,000,000 axons in optic nerve (vs 30,000 in auditory nerve) |
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Term
|
Definition
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Term
visible parts of the eye:
iris |
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Definition
- largely a muscle that expands and contracts pupil in response to light
- phenotypically unique (iris scan) |
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Term
visible parts of the eye:
sclera |
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Definition
|
|
Term
visible parts of the eye:
pupil |
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Definition
| often used to determine neurological function |
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Term
| What does the human eye see? |
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Definition
| light waves along the visual spectrum |
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Term
|
Definition
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Term
| region important for transduction- |
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Definition
|
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Term
|
Definition
- structure of eye important for transduction
- retina contains neurons, glial cells and two types of photoreceptors |
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Term
|
Definition
| -shaped like a rod -insensitive to color -work well under low illumination -20,000,000/eye -location: found around the periphery of the retina -requires extended time until optimal function |
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Term
|
Definition
-shaped like a cone
-sensitive to color
-work best in bright light
-5,000,000/eye
-location: found around the fovea of the retina
-responsible for sharp images and vision
-works optimally very quickly |
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Term
| a low ratio of synaptic connections between neurons ensures- |
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Definition
| higher definition and sharpness compared to a higher ratio |
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Term
| Cones: Sharp, accurate vision (pic) |
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Definition
|
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Term
| Rods: less sharp focused visual input |
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Definition
|
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Term
| two levels of communication within the neural cells- |
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Definition
1) rods and cones – bipolar cells – ganglion cells (axons make up the optic nerve) to CNS
2) across a single layer (rods and cones communicate with each other; bipolar cells communicate with each other; etc) |
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Term
Parkinsons's Disease:
Lifespan |
|
Definition
| - Normal, the disease does not shorten your lifespan |
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Term
| What causes the blind-spot we have in both our eyes? |
|
Definition
| optic nerve (ganglion cell axons) |
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Term
Explanation of color vision:
trichromatic theory |
|
Definition
- Also known as Young-Helmholz
- occurs at level of cones
- 3 different cones more sensitive to different wavelengths (ie colors) |
|
|
Term
|
Definition
- abnormalities in cones can explain red/green color blindness
- Very rare to see complete color blindness
- ~ 7% of US males (10,000,000) compared to 0.4% women - red/green
- X-linked phenomenon |
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|
Term
Trichromatic theory can't explain:
negative afterimage |
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Definition
| - phenomenon that occurs as a result of overactivity or inhibition of neurons (due to color stimulation) |
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Term
Explanation of color vision:
opponent process theory |
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Definition
- occurs at level of bipolar cells
a) red/green; yellow/blue
b) one color excites bipolar cell; other color inhibits it |
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Term
| Problems with Opponent Process Theory |
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Definition
- says nothing about complexity as information reaches occipital lobe –
- prestriate |
|
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Term
|
Definition
- primary occipital cortex
- multiple layers of higher association cortex |
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Term
|
Definition
| - stimuli applied to the skin |
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Term
Exteroreceptive System:
types of stimuli |
|
Definition
- Touch (mechanical stimuli)
- Temperature (thermal stimuli)
- Pain (nociceptive stimuli) |
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Term
|
Definition
- a necessary sense
- too little or too much – yikes!
- No obvious cortical representation |
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Term
Neurotransmitters involved in Pain:
Substance-P |
|
Definition
Substance-P
- Most pain is a result of substances released by damaged tissues including substance P |
|
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Term
| What else causes release of Substance-P? |
|
Definition
Capzasin/Capsaicin
- ingredient: Oleoresin Capsicum (as Capsaicin) |
|
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Term
| Why does a large amount of Substance-P release cause relief? |
|
Definition
- Substance P is a large peptide and synthesis can take time SO
- Release of large amounts of substance P results in a brief time (when more is being synthesized) that is “pain-free” |
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Term
Neurotransmitters involved in Pain:
Endogenous opioids |
|
Definition
endorphins – endogenous morphine-like substances
- may explain acupuncture, placebo effects |
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|
Term
Neurotransmitters involved in Pain:
(list 2) |
|
Definition
- Substance-P
- Endogenous opioids |
|
|
Term
|
Definition
| pain can be suppressed by cognitive and emotional factors |
|
|
Term
Descending Pain Control:
PAG |
|
Definition
|
|
Term
A descending pain control pathway:
Three discoveries made this possible |
|
Definition
1) Electrical stimulation of the PAG has analgesic (pain-blocking) effects
2) PAG and other brain areas have large amounts of opiate receptors
3) Existence of endogenous opiates (natural analgesics) - endorphins |
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Term
|
Definition
| cancers, debilitating arthritis, back pain, undiagnosed |
|
|
Term
Chronic pain:
treatments (list 4) |
|
Definition
1) drugs – morphine derivatives (oxycontin)
2) ESB - periaqueductal gray
3) stimulation of spinal cord
4) cutting dorsal roots |
|
|
Term
Chronic pain:
Phantom Limb (treatments) |
|
Definition
1) drugs – antidepressants; antiseizure medication
2) cutting dorsal roots
3) anesthetizing stump |
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Term
| CNS Regions Involved with Motor Function (list 4) |
|
Definition
- Cerebral cortex
- Cerebellum
- Basal Ganglia
- Movement Disorders |
|
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Term
| 3 Principles of Sensorimotor Function |
|
Definition
1) Hierarchical organization
2) Motor output guided by sensory input
3) Learning (experience) changes the nature and locus of sensorimotor control
(Conscious to automatic, for example) |
|
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Term
| Cerebellum and Basal Ganglia |
|
Definition
- Interact with different levels of the sensorimotor hierarchy
- Coordinate and modulate
- Can help with visually guided responses despite cortical damage |
|
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Term
|
Definition
- 10% of brain mass, > 50% of its neurons
- Input from primary and higher association ° motor cortex
- Input from brain stem motor nuclei
- Feedback from motor responses
- Involved in fine-tuning and motor learning
- May also do the same for cognitive responses |
|
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Term
|
Definition
- A collection of nuclei
- Part of neural loops that receive cortical input and send output back via the thalamus
- Modulate motor output and cognitive functions |
|
|
Term
Motor or Movement Disorders:
Muscular dystrophy |
|
Definition
- Group of 30+ genetic disorders mainly characterized by muscle degeneration
- Duchenne - most common form
- primarily affects boys- caused by the absence of dystrophin, a protein involved in maintaining the integrity of muscle. |
|
|
Term
Motor or Movement Disorders:
Myasthenia gravis |
|
Definition
- loss of cholinergic receptors at neuromuscular junction
- Muscles fatigue and weaken with repeated movements
- Autoimmune disorder
- Treatment: Anti cholinesterase agents, immunosuppressive drugs, thymectomy |
|
|
Term
Motor or Movement Disorders:
Amyotropic lateral sclerosis (ALS) |
|
Definition
- degeneration of motoneuron
- Typically rapidly progressive and fatal ( 3 – 5 years after diagnosis)
- Disease of motor neurons
- Eventually, all muscles under voluntary control are affected
- As many as 20,000 in US have ALS, with an estimated 5,000 people diagnosed each year
- 90 to 95 percent – unknown cause
GLU hypothesis? Treatment? |
|
|
Term
neurodegenerative disorders:
(list 2) |
|
Definition
| Parkinsons Disease and Huntingtons |
|
|
Term
neurodegenerative disorders:
Parkinsons Disease - Facts |
|
Definition
- typical onset over 60
- Janet Reno, Muhommed Ali, Michael J. Fox |
|
|
Term
neurodegenerative disorders:
Parkinsons Disease - features |
|
Definition
| - difficulty initiating movement, cogwheel rigidity, resting tremor and postural instability (fall easily). |
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|
Term
neurodegenerative disorders:
Parkinsons Disease - What do we see? |
|
Definition
| - Progressive degeneration of dopamine neurons in the midbrain (substantia nigra) that project to basal ganglia |
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|
Term
neurodegenerative disorders:
Parkinsons Disease - causes |
|
Definition
Unsure; certain risk factors suggest environmental contaminants
- age, well water, farmers, boxers
- MPTP model |
|
|
Term
neurodegenerative disorders:
Parkinsons Disease - MPTP-induced |
|
Definition
- 1982 – San Francisco - Designer Drug that was supposed to mimic heroin
- Seven heroin addicts at ER. All showed signs of severe Parkinsons like Disease
- Found that the drug had been contaminated with a toxin called MPTP |
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|
Term
neurodegenerative disorders:
Parkinsons Disease - treatment |
|
Definition
- Pharmacological: increase dopamine (DA) levels with a drug like l-dopa
- other drugs that slow down breakdown of DA or act as DA agonists |
|
|
Term
neurodegenerative disorders:
Parkinsons Disease - Problem with DA increase |
|
Definition
- over time – extended off periods
- motor side effects from medication
- other side effects of medication |
|
|
Term
neurodegenerative disorders:
Parkinsons Disease - Other treatments |
|
Definition
- Various forms of brain surgery (Lesion part of thalamus)
- deep brain stimulation
- fetal tissue implantation (RECENT RISK OF SIDE EFFECTS) |
|
|
Term
neurodegenerative disorders:
Hunningtons Disease |
|
Definition
- characterized by progressive degeneration of CNS
- early symptoms include cognitive dysfunction, memory problems, depression, clumsiness or motor incoordination
- usually first symptoms emerge between 30 and 45 years of age
- genetic basis: offspring has 50% of inheriting disorder if parent has it |
|
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Term
| Who studies and treats brain disorders? |
|
Definition
- Clinical neuropsychologists
- Neurologists
- Neurosurgeons
- Rehabilitation therapists
- Occupational therapists |
|
|
Term
Brain can be damaged many ways
(list 7) |
|
Definition
- head injuries via cerebral trauma
- Stroke/hypoxia
- tumors
- Infections
- Drugs or toxic substances
- exposure to radiation
- degenerative conditions |
|
|
Term
|
Definition
- brain is jarred, bruised or cut
- frontal and temporal lobe sites most common
- (alcoholics, epilepsy) |
|
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Term
|
Definition
| brain is jarred resulting in temporary loss of consciousness (often lasting just few minutes) |
|
|
Term
|
Definition
more severe than concussion; brain is jarred but also shifted out of position in skull (so generally bruised)
- coma, convulsions, speech loss |
|
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Term
|
Definition
foreign object enters skull and damages or destroys brain tissue
- depending on area of damage determines extent of damage |
|
|
Term
|
Definition
- Assistant to President Reagan
and White House Press Secretary
until 1981
- left leg partially paralyzed, left arm
completely paralyzed, memory and speech impaired. |
|
|
Term
| Cerebrovascular accident (CVA): |
|
Definition
- stroke; sudden onset cerebrovascular disorder that causes brain damage
- 2 types: cerebral hemorrhage, cerebral ischemia
- Estimates as high as 750,000 people/yr
- 3rd leading cause of death and most common cause of adult disability |
|
|
Term
Cerebrovascular accident (CVA):
cerebral hemorrhage |
|
Definition
Bleeding in the brain
- Most frequent cause – high blood pressure
- neurons do not receive necessary blood/oxygen/energy PLUS – flooded with all sorts of chemicals normally contained in blood vessels (causes all sorts of imbalances) |
|
|
Term
Cerebrovascular accident (CVA):
cerebral ischemia |
|
Definition
disruption of blood supply to an area of the brain (caused by blockade/obstruction of blood flow.
- so neurons do not receive necessary blood/oxygen/energy |
|
|
Term
Cerebrovascular accident (CVA):
consequences/stats |
|
Definition
- 10 percent of stroke survivors recover almost completely
- 25 percent recover with minor impairments
- 40 percent experience moderate to severe impairments requiring special care
- 10 percent require care in a nursing home or other long-term care facility
- 15 percent die shortly after the stroke |
|
|
Term
|
Definition
|
|
Term
2 ways that strokes kill neurons:
directly (usually immediate) |
|
Definition
| deprivation of oxygen or blood within minutes will kill neurons |
|
|
Term
2 ways that strokes kill neurons:
more indirectly (usually more delayed) |
|
Definition
| overexcitation due to release of ions and NT from dead neurons- particularly glutamate (at NMDA receptors) |
|
|
Term
|
Definition
- PROBABLY NOT neurons that die directly
- MAYBE – damage that occurs as 2ndary injury |
|
|
Term
|
Definition
A tumor is a mass of cells that grows independently of the rest of the body – - a cancer
- most common form: glioblastoma |
|
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Term
| How can tumors affect brain tissue? |
|
Definition
1) Compression
2) Infiltration |
|
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Term
|
Definition
| Bacterial Infection and viral infections |
|
|
Term
Differences between bacteria and viruses:
Bacteria |
|
Definition
- living/ can reproduce/divide
- good bacteria/bad bacteria
- can be treated with antibiotics |
|
|
Term
Differences between bacteria and viruses:
Viruses |
|
Definition
- not alive?
- piece of nucleic acid that infects other cells
- kills host cell
- difficult to treat because virus constantly mutates |
|
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Term
|
Definition
- bacterial encephalitis: encephalitis – swelling of the brain
- bacterial meningitis: swelling of the meninges |
|
|
Term
Strokes:
Risk Factors->Protective factors |
|
Definition
high blood pressure -> cholesterol (HDL)
cigarettes -> exercise
high cholesterol (LDL)-> diet |
|
|
Term
CNS infections:
Symptoms (for both kind) |
|
Definition
| high fever, severe headache, nausea, confusion, disorientation, personality changes, convulsions, memory loss, drowsiness, and coma |
|
|
Term
| Other Bacterial Infections (list 2) |
|
Definition
Neurosyphilis
Lyme Disease |
|
|
Term
| Viral Infections (list 4) |
|
Definition
- viral encephalitis, meningitis
- rabies – has particular affinity for the nervous system
- West Nile Fever- from mosquitos
- HIV |
|
|
Term
|
Definition
- virus infects glia and other cells (probably not neurons) although it causes neuronal damage
- impaired concentration, mild memory loss
- HIV cocktails and the blood brain barrier |
|
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Term
|
Definition
transmissible spongiform encephalopathies
- once disease is apparent – demise is relatively quick
- A number of diseases that are all considered transmissible spongiform encephalopathies (called this because of the spongy nature of what the brain looks like) |
|
|
Term
|
Definition
| abnormal protein that appear to destroy normal proteins and cause them to fold onto themselves in the CNS |
|
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Term
|
Definition
- Kuru: Papau New Guinea
- Scrapies: in sheep
- Mad cow disease: in cows |
|
|
Term
Prion diseases:
Human cases |
|
Definition
- Kuru
- Creutzfeldt-Jakob Disease (CJD)
- Fatal Familial Insomnia |
|
|
Term
Prion diseases:
Classic CJD |
|
Definition
- Very rare (total estimates 1 per 1,000,000 people)
- Sporadic CJD (occurs occasionally with no known cause) – most common but still rare
- Familial CJD (an inherited form of CJD that occurs in families) - accounts for only 10 – 15% |
|
|
Term
Prion diseases:
Variant CJD |
|
Definition
- caused by an unconventional transmissible agent.
- Variant CJD was first described in 1996 in the United Kingdom |
|
|
Term
Neurodegenerative disorders:
characteristics |
|
Definition
- neurons begin to die: unclear the cause;
- none of the treatments for these diseases stop the progression of the disease |
|
|
Term
Neurodegenerative disorders:
examples (list 3) |
|
Definition
- Alzheimers Disease
- Parkinsons Disease
- Huntingtons Disease |
|
|
Term
Neurodegenerative disorders:
Alzheimers disease (facts) |
|
Definition
- characterized by tangles and plaques
- characterized by slow decline- most recent information first
- up to 4 million Americans with it
- most common form of dementia
- person can live with disease |
|
|
Term
Neurodegenerative disorders:
Alzheimers disease (notes) |
|
Definition
- cholinergic neurons are particularly susceptible (treatments mostly increase ACh activity). Latest treatment is memantine.
- early onset AZ vs later onset (Genetics; trisomy 21) |
|
|
Term
| Neuroplasticity and Responses to Nervous System Damage |
|
Definition
- Degeneration: deterioration
- Regeneration: regrowth of damaged neurons
- Reorganization
- Recovery |
|
|
Term
|
Definition
degeneration of the distal segment, between the cut and synaptic terminal
- cut off from cell’s metabolic center
- swells and breaks off within a few days |
|
|
Term
|
Definition
degeneration of the proximal segment, between the cut and cell body
- progresses slowly
- if regenerating axon makes a new synaptic contact, the neuron may survive |
|
|
Term
|
Definition
| Regeneration is virtually nonexistent in the CNS of adult mammals and unlikely, but possible, in the PNS |
|
|
Term
| Neural Regeneration in the PNS |
|
Definition
- If the original Schwann cell myelin sheath is intact, regenerating axons may grow through them to their original targets.
- If the nerve is severed and the ends are separated, they may grow into incorrect sheaths
- If ends are widely separated, no meaningful regeneration will occur |
|
|
Term
|
Definition
|
|
Term
|
Definition
| make multiple sheaths of myelin |
|
|
Term
| Reorganization can occur in the... |
|
Definition
| Central Nervous System (CNS) |
|
|
Term
| Recovery of Function after Brain Damage |
|
Definition
- Difficult to conduct controlled experiments on populations of brain-damaged patients
- Can’t distinguish between true recovery and compensatory changes
- Cognitive reserve – education and intelligence – thought to play an important role in recovery of function – may permit cognitive tasks to be accomplished new ways
- Adult neurogenesis may play a role in recovery |
|
|
Term
| Treating Nervous System Damage (list 4) |
|
Definition
- Reducing brain damage by blocking neurodegeneration
- Promoting recovery by promoting regeneration
- Promoting recovery by transplantation
- Promoting recovery by rehabilitative training |
|
|
Term
| Reducing brain damage by blocking neurodegeneration |
|
Definition
- Various neurochemicals can block or limit neurodegeneration
- Nerve growth factor – blocks degeneration of damaged neurons
- Estrogens – limit or delay neuron death
- Neuroprotective molecules tend to also promote regeneration |
|
|
Term
| Promoting Recovery by Promoting Regeneration |
|
Definition
- While regeneration does not normally occur in the CNS, experimentally it can be induced
- Eliminate inhibition of oligodendroglia and regeneration can occur
- Provide Schwann cells to direct growth |
|
|
Term
| Promoting Recovery by Neurotransplantation |
|
Definition
- Fetal tissue: PD discussion
- Stem cells: Rats with spinal damage “cured”, but much more research is needed |
|
|
Term
| Adult Stem Cell neurogenesis |
|
Definition
Two regions in the brain that we know this occurs
- Part of the hippocampus
- Subventricular zone: area of lining of ventricles in brain |
|
|
Term
| Promoting Recovery by Rehabilitative Training |
|
Definition
- Constraint-induced therapy: down functioning limb while training the impaired one – create a competitive situation to foster recovery
- Facilitated walking as an approach to treating spinal injury
- These both can be beneficial but can also be tremendously stressful |
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