Advanced Neuro Exam 1

Determine which part of the neuroectoderm gives rise to (a) CNS (b) PNS

CNS: the neural tube gives rise to the brain and spinal cord. PNS: the neural crest cells give rise to the PNS

Identify at least one other neurodegenerative disease with neurofibrillary tangles detected in the living person's brain.

Chronic traumatic encephalopathy (CTE)

Differentiate between (a) communicating hydrocephalus and (b) non-communicating hydrocephalus.

Congenital Hydrocephalus is a disease where there is a dilated lateral ventricle. The production of CSF is not affected however it is not able to be reabsorbed back into circulation. Communicating Hydrocephalus is where CSF is produced and is able to circulate through the ventricular chambers normally but the arachnoid granulations do not allow the CSF to be reabsorbed back into the bloodstream. In Non-communicating Hydrocephalus there is a blockage/ obstruction along one or more of the narrow passages connecting the ventricles. This could be due to tumors, etc. The CSF accumulates and causes ventricular and skull expansion that could cause brain damage.

Identify the human peripheral neuropathy associated with a gene mutation in the PMP-22 gene

CMT1A - Charcot-Marie-Tooth Disease.

Identify and describe the microtubule associated "motor" protein responsible for fast Anterograde axonal transport.

Kinesin- uses ATP as an energy source to move materials on the cytoskeleton. Both kinesin and dynein are dependent on forming an interaction with the turbulent monomers. Fast transport occurs at 200-400 mm a day.

Describe the location of GAP-43 protein during regeneration of axons following injury.

GAP-43 is re-expressed in axon terminals during axonal regeneration following injury.

Describe the relative degree of aggressiveness of a glioblastoma multiformes (GBM) and a patient's prognosis compared to low-grade brain tumors. (b) Describe the significance of a "ring-enhancing mass" found on a CT scan of the human brain.

GBM is very aggressive and fast growing, highly malignant accounting for 50% of brain tumors (typically aged 60-69). Typically 7-12 months after diagnosis is the survival rate and only 10% alive after 2 years. The ring enhancing means that with an injection of contrast material, the periphery(ring shaped) of the lesion is brighter (enhances) than the rest of the lesion.

Describe the relationship of the organic structure of sulfatide and galactorcerebroside and, (b) describe a proposed function of these two lipids in the myelin surrounding an axon.

GalC (galactorcerebroside ) converts to sulfatide when a hydroxyl group is replaced by a sulfate group. These lipids function by forming a calcium bridge via ionic bonds in order to maintain structure during the wrapping of myelin. These ionic bonds keep the myelin together when the myelin wraps around the axon and overlaps.

Describe reasons a scientist would employ the technique of "single-labeling" of individual neurons

to show fine details of selected individual neurons of brain tissue instead of the Golgi non-selective approach.

Describe three events occurring in the proximal stump of a peripheral nervous system axon following axotomy.

axon sprouting. new growth cones are formed mimicking events seen during development. Re-expression of GAP-43 levels in growth cone

Describe the features associated with Dandy-Walker malformation.

characterized by an enlarged posterior cranial fossa(part of skull), aplasia of the cerebellum, and enlargement of the 4th ventricle. Slow motor development and motor coordination.

Identify and describe the class of molecules expressed by damaged cells and immune cells following injury to the central nervous system that function collectively to promote astrocytic reactive gliosis (b) Provide the names (both the abbreviation and full name) of some of these molecules that can directly stimulate astrocytes to form gliotic scar tissue.

cytokines. Cytokines are cell-signaling molecules released by damaged cells (neurons, astrocytes, oligodendrocytes) and inflammatory cells (neutrophils, macrophages, microglia). Molecules that can directly stimulate astrocytes to form gliotic scar tissue include FGF (fibroblast growth factor), TGF-𝛃 (transforming growth factor), CNTF (ciliary neurotrophic factor), IL-1 (interleukin 1), and Endothelin - 1.

Describe the specific descending (motor) tract that degenerates in amyotrophic lateral sclerosis (ALS) and subsequently becomes devoid of myelin in the spinal cord.

there is a selective loss of the descending myelinated axons of the cortical spinal tract. This technique can be applied and shows the lack of myelin stain in the descending cortical spinal tract because there is no myelin present from degeneration.

Describe reasons a scientist would employ the technique of "dual-labeling" of individual neurons.

to identify one cell with two different indicators. This can select for function, structure, and reaction to different neurotransmitters.

Describe a medical technique that can correct for complete DiGeorge's syndrome.

to perform a transplant of thymus tissue to obtain working thymus cells.

Describe the chemicals used for Golgi staining and (b) describe the scientific utility of the Golgi stain.

potassium bichromate and then silver nitrate.

In reference to tissues of the adult human body, describe (a) several peripheral ganglia and (b) describe the region of the adrenal gland that formed due to contributions from migrating neural crest cells during embryonic development.

several peripheral ganglia: Dorsal root ganglia, sympathetic ganglion, and preaortic ganglion. The region of the adrenal gland that formed due to contributions from migrating neural crest cells during embryonic development is the suprarenal gland.

Describe two types of neurons based on whether or not dendritic spines are present.

spiny neuron- has more surface area for synaptic connections with other cells due to the spiny dendrites. There are much more spiny neurons in CNS, aspiny neuron- There are much less aspiny neurons compared to spiny neurons. There is relatively less surface area for synaptic connections.

Provide a brief description of (a) the cognitive strengths and (b) cognitive impairments associated with William's Syndrome.

strengths: is language and face processing. They tend to be dramatic storytellers and be overly social. weaknesses: spatial cognition.

Identify the microtubule associated protein that forms neurofibrillary tangle in Alzheimer's disease.

tau protein

differentiate between the conditions of (a) spina bifida occulta,

the failure of vertebral lamina to fuse and complete the bony neural arch. It is common in sacrolumbar region and with skin and hair over the region. It is a very mild condition.

Briefly describe gene mutations, gross features, and histological features found in the brains of people diagnosed with lissencephaly

the neuroblasts are able to migrate out of the VZ because the FLN1 gene is not affected. Once the neuroblasts migrate to the higher regions forming the cortical plate, the migration and formation of the 6 layer cerebral cortex is severely disrupted. Development of the brain is halted so that the division of the brain is unfinished as well as gyri not forming. It is genetic defect in LIS-1 gene cause a generalized defect in neuronal migration.

Describe the concept of "neurulation"

the process of forming the neural tube. In the embryo around 18 days, in the midline of the ectoderm called the notochordal plate has a molecule release causing the invagination causing the neural tube.

Describe why the original cell theory proposed by Theodore Schwann did not include the brain.

the techniques used in the 1800s were not advanced enough to fix CNS tissues. The stains also were limited at the time to be able to be viewed in neural tissue. The cell theory states that all tissues are composed of cells.

Describe the three primary brain vesicles that appear in an early stage embryo (b) Describe the anatomical location of the cephalic flexure and the cervical flexure relative to the three brain vesicles.

-Prosencephalon (forebrain), -Mesencephalon (midbrain), - Rhombencephalon (hindbrain). The cephalic flexure is between the midbrain and the hindbrain, The cervical flexure is between the hindbrain and the spinal cord.

Identify the three cellular elements forming the "tri-partate" synapse and (b) describe at least one proposed function of the astrocyte in the tri-partate synapse

-presynaptic cell -postsynaptic cell -their surrounding glial cells (astrocytes) The tripartite synapse is the process in which after a neurotransmitter does its job in the synaptic cleft and the astrocyte can remove/deactivate it. Astrocytes in regards to the tri-partate synapse are capable of producing changes in their intracellular calcium concentrations through release of calcium stores from the endoplasmic reticulum. Astrocytes communicate bidirectionally with neurons, are capable of responding selectively to stimuli and integrate/modulate information from their synaptic inputs.

Provide two definitions of the concept of "synaptic plasticity"

1. an increase in synaptic efficacy due to increases in functional activity 2. changes in structure or function in a neural system in response to experimental manipulations or injury during development or in the adult, as well as changes that occur as a result of aging and disease.

Describe the four several sequential steps observed during development of neuronal circuits and formation of synapses

1: is the specification of distinct neuronal cell types for example motor neurons. 2: is the directed outgrowth of developing neurons via molecular cues. This is where the cell migrates 3.: is the selection of appropriate synaptic partners. 4: is the refinement of connections through the elimination of certain neurons, axons, and synapses during critical periods of development via environmental cues. There can be numerous axon terminals at a target cell. Over time its been found that the motor neurons that form a motor unit have innervation by just one axon terminal at the muscle fiber and a motor neuron can innervate multiple muscle fibers.

describe three cardinal signs of morphogenesis in the early stage embryo.

1: polarity a change in the regions of the embryo at the caudal and cranial ends of the embryo. 2. There is bilateral symmetry having a right and left side, 3. regionalization where the head region develops faster/larger than the tail end.

Identify (a) the origin of a neurilemmal cell and (b) describe functions of a neurilemmal cell.

A neurilemmal cell is derived from a Schwann cell. A neurilemmal cell proliferates extensively after injury (13x as many after 25 days).They forms the "regeneration tube" (Bands of Bunger) which functions to unite the distal/proximal stumps. They also function to guide and nurture the growth cone

Describe characteristics that differentiate neurons based on their function compared to their morphology. (refer to the slide in the recorded lecture with three neurons)

A neuron with multiple processes extending from the cell body ending in dendrites and a single axon is classified to as a multipolar neuron which is a typical motor neuron. A neuron with a single process which bifurcates into 2 processes/axons is classified to as a unipolar neuron which is a typical sensory neuron sometimes involved with peripheral nerves. A neuron with a 2 processes extending from the cell body is classified to as a bipolar neuron which is typically a sensory neuron found in the retina.

Describe some characteristics of proteolipid protein (PLP), a protein uniquely expressed by oligodendrocytes in CNS myelin.

A proteolipid protein (PLP) is another protein in CNS myelin. PLP is a very hydrophobic, integral membrane protein. Its function is to hold adjacent myelin membrane sheets together. PLP is essential for oligodendrocyte development .Mutations in the PLP caused defective myelin creation of a "jimpy mouse" which is the animal model for multiple sclerosis

Provide a brief description of the type of astrocyte that contains less glial fibrillary acid protein (GFAP) and is principally found in gray matter. (b) Provide a brief description of the type of astrocyte that contains more GFAP and is principally found in white matter

A protoplasmic astrocyte is found in gray matter of either the brain or spinal cord and contains less GFAP. It functions to maintain the blood brain barrier, repair damaged tissue, create structure for the brain and spinal cord, regulate the interstitial environment including transport nutrients, regulate capillary blood flow, and absorb/recycle neurotransmitters. A fibrous astrocyte is found in white matter and contains more GFAP in their cytoplasm. As stated, astrocytes function to maintain the blood brain barrier, repair damaged tissue, create structure for the brain and spinal cord, regulate the interstitial environment including transport nutrients, regulate capillary blood flow, and absorb/recycle neurotransmitters.

Identify the human leukodystrophy associated with a defect in metabolism of very long chain fatty acids (VLCFs) and, (b) describe approaches to treating a person with this leukodystrophy

Adrenoleukodystrophy- It involves the degeneration of white matter and the adrenal gland. VLCFs normally insulate the nerve fibers. An approach to treat a person with adrenoleukodystrophy is gene therapy similar to the mechanism of adrenoleukodystrophy gene therapy. A different approach was an oil created that starts a chemical reaction in these patients which reduced the generation of white matter.

Describe the process of reactive astrogliosis in the central nervous system.

After an injury to brain tissue, astrocytes are stimulated to work to form scar tissue in the CNS. This process is known as Reactive Astrogliosis.

Identify some microtubule associated proteins

Alpha and beta tubulin proteins. Other proteins include microtubule associated proteins (MAPs) like MAP 1 found in glia, axons, and dendrites and MAP 2 only found in neuron dendrites. A MAP found primarily in axons is Tau. Motor proteins like kinesin and dynein are also types of microtubule proteins.

Describe approaches to treating a person with Metachromatic leukodystrophy.

An approach to treating patients with metachromatic leukodystrophy is gene therapy. This gene therapy harvests gene stem cells and introduce it into a viral vector. The viral vector is introduced into the individuals genome via a transduced cell. This cell is introduced back into the individual which makes it way back into the bone marrow allowing for the normal production of the gene.

Provide a brief description of the four (4) major types of synapses based on the parts of neurons attaching to each other.

An axo-dendritic synapse refers to a synapse at the axon terminal and a dendrite.. An axo-somatic synapses refers to a synapse formed at the axon terminal and the cell body. An axo-axonic synapses refers to a synapse formed at the axon terminal on the axon at the target cell. These synapses all include the release of a neurotransmitter to cause a membrane potential change at a target cell. These are the synapses most studied. A dendro-dendritic synapse has been researched and it is still known what their exact purpose is. They involve a point of contact at 2 dendrites

Compare events observed during the original formation of synapses to events observed during re-innervation following injury.

At birth muscle fibers are innervated by multiple motor axons, during the first few postnatal weeks, axonal convergence decreases as all but one input is eliminated from each fiber. Occurs by branch removal rather than motor neuron cell death. After nerve injury motor axons grow back to the denervated muscles. Axons sprout to occupy many muscle fibers. Sometimes muscle fibers will become multiply innervated. About 32 weeks after reinnervation, synapse elimination occurs, largely restoring single innervation to each muscle fiber.

Describe events occurring in the distal stump of a peripheral nervous system axon following axotomy

At the distal stump, Wallerian degeneration occurs. In this process, within 24 hours axonal swelling occurs and varicosities form. Within 48 hours, macrophages infiltrate tissue to facilitate a disintegration of the dystrophic axon, loss of synaptic connection from target, removal of myelin wrap, and transformation of Schwann cell into neurilemmal cell.

Describe major influencing factors guiding axon growth cone migration in the developing human nervous system including chemo-attractant, chemo-repelling, contact attracting, and contact repelling molecules

Axon migration is important in neural development. This allows growing axons to reach specific destinations in order to form the complex neuronal networks throughout the body. Growth cones could be "pushed" from behind by a chemorepellent, "pulled" from far out by a chemoattractant. The axon growth cones are then "hemmed" by attractive and repulsive local cues. Chemo-repelling molecules include semaphorins (secreted) and netrins.Chemo-attracting molecules include Netrins. Contact Repelling molecules include Eph Ligands, semaphorins (transmembrane), and ECM (tenascins)so axons do not grow into that certain territory. Contact attracting molecules include Ig CAMs (cell adhesion molecules), cadherins, and ECM (laminins).

Compare and contrast the clinical utility of tools used to image the human central nervous system including (a) CT scans, (b) MRI, (c) PET scan, and (d) angiography.

CT scans-- are 2 dimensional reconstructions from x ray images. They are efficient in discriminating between tissue densities. It is used to view tumors, vascular abnormalities, and sites of trauma. MRIs-- use a magnetic field to view images of exquisite detail able to differentiate white matter from gray matter. MRIs can also be enhanced to differentiate small tumors from surrounding unaffected brain tissue. PET scans-- detect the emission of electrons from radioactive substance. It indicates physiologic or metabolic processes like glucose/oxygen uptake, cerebral blood flow, and the effects of drugs. Angiography-- is a radiological technique to demonstrate blood flow using serial x-rays. It can provide many details about vessels such as patency (openness), location, size, and flow pattern.

Name the two neuroscientists regarded as the "fathers of neuroscience" who won the Nobel Prize in 1906.

Camillo Golgi and Santiago Ramon Y Cajal.

Which of the Nobel Prize winners from 1906 proposed the reticular theory and describe what the reticular theory states.

Camillo Golgi. The theory states that the nervous system is made of a network of fibers that are all connected.

Differentiate between (a) Chiari type I malformation and (b) Chiari type II malformation.

Chiari type I is where the primary pathology occurs in the occipital skull and secondarily causes cerebellar tonsils to extend down the vertebral canal ("squeezed out" mechanism) Both have symptoms including compression of the brainstem, weakness of muscles, ataxia, and corticospinal tract involvement including progressive spastic paresis, increased tendon reflexes, and babinkski sign. This may cause obstruction of CSF flow and medullary compression. Chiari type II consists of lumbar myelomeningocele which seems to pull down on the brain and causes downward extension of the cerebellum through the foramen magnum ("pulled down" mechanism). Changes can also include caudal displacement of the medulla, malformation of the tectum, aqueductal stenosis, and heterotopia.

Describe the effect that the enzyme, chondroitinase, might promote when applied to an experimental (animal) model of spinal cord injury.

Chondroitinase might promote formation of new synapses by attacking CSPG.

Describe the genetic mutation responsible for DiGeorge's syndrome and (b) describe some of the anatomical and physiological derangements associated with DiGeorge's syndrome

DiGeorge's syndrome has been reported to arise due to defective cardiac neural crest cell migration that can be linked to a mutation in a gene located at chromosome 22 Q11. Due to the defect in neural crest migration, resulting in a lack of development of the thymus. The lack of development of a thymus puts the affected patient at a high risk for infections due to immunodeficiency. There are also possibilities for cardiac anomalies, hypoparathyroidism, cleft palate, small mouth, and low set ears.

Provide a detailed description of methods used in the landmark experiment conducted by Dr. Geoffrey Raisman in 1997 to promote axon growth and re-innervation following injury to the central nervous system (spinal cord).

Dr. Geoffrey Raisman grafted olfactory sheathing cells into unilaterally severed corticospinal tract. Recovery was noted in majority of animals. The experiment resulted with ensheathing cells migrating widely in the cord possibly accompanying axons. This experiment was performed on a human subject resulting in recovery as well.

Provide a detailed description of methods used in the landmark experiment conducted by Dr. Lars Olsen in 1996 to promote axon growth and re-innervation following injury to the central nervous system (spinal cord).

Dr. Lars Olsen performed an experiment where PNS tissue (which has the ability to regenerate after injury) was grafted into injured CNS tissue at site of lesion in spinal cord transection. This graft was known as the "bridging graft." Axons regenerated through bridging graft into distal cord gray matter. This experiment showed impressive re-innervation.

Provide a detailed description of methods used in the landmark experiment conducted by Dr. Martin Schwab in 1994 to promote axon growth following injury to the central nervous system (spinal cord).

Dr. Martin Schwab conducted an experiment where two agents were administered to rats with coricospinal tract lesions in the mid-thoracic spine. He administered IN-1, an inhibitor neutralizing antibody directed against NI-250 (Nogo B) and NI-35 (Nogo A). He also administered neurotrophin 3, a cytokine that promoted axon sprouting. This group of drugs admitted resulted in considerable axon growth into lumbar/sacral regions

Describe some human conditions associated with alterations with dendritic spine morphology where there might be either decreased spine density or increased spine density.

Drug addiction have presented with an Increase in dendritic spine density. Alzheimer's and Parkinson's diseases have be found to decrease dendritic spine density along with neuron death. A condition called Mild Cognitive impairment (MCI) which is believed to precede Alzheimer's also has been found to have a decrease in dendritic spines. There has also been research linking memory formation during sleep and an increase in dendritic spine density.

Discuss how perturbation in light activity in eyes during the "critical period" of neural development might affect width of ocular dominance columns.

During the critical period of neural development, if one eye remains closed and the other eye is open, the eye that is closed will have a smaller area in the column than the open eye's column area.

Identify and describe the microtubule associated "motor" protein responsible for fast Retrograde axonal transport.

Dynein- uses ATP as an energy source to move materials on the cytoskeleton.

Describe the relative location of ependymal cells in (a) the brain and, (b) the spinal cord.

Ependymal cells in the brain line the ventricles and choroid plexus in the brain. Ependymal cells in the spinal cord line the central canal.

Identify the relative location where ependymoma brain tumors are found in the central nervous system.

Ependymomas commonly appear where ependymal cells appear around ventricles or central canal of the spinal cord.

Describe the proposed concept of the "protection" and "punishment" theory that might account for the process of synapse elimination during formation of the human nervous system.

Experimental evidence suggests that synapse elimination results from activity-mediated signals in polysynaptic cells. Postsynaptic receptor activation may have two opposing signals with a muscle fiber. One is a "punishment" signal sent to weaker synapses to eliminate them. The second is "protective" signals described as clouds under the synapse that protect the more active synapses.

List cellular materials transported by (a) fast, (b) intermediate, and (c) slow rates of axonal transport

FAST- Neurotransmitter vesicles move at a fast rate of axonal transport at 200-400 mm/day. Intermediate-Mitochondria (50 mm/day) and myosin proteins (15 mm/day)move at an intermediate rate of axonal transport. SLOW-Microfilaments (2-4 mm/day)and neurofilaments (.2-1 mm/day) move at a slow rate of axonal transport.

Compare (a) factors in the central nervous system that inhibit functional recovery following injury to (b) factors in the peripheral nervous system that promote functional recovery following injury.

Factors in the CNS that cause inhibition include potent neurite growth inhibitors, axon sprouts and stops, formation of gliotic scars, and weak expression of neurotrophic factors. Factors in the PNS that cause promotion include a strong up-regulation of neurotrophic factors, growth promoting substrate molecules, and neurilemmal tube guiding the axon to target. Gliotic scars are formed following a brain injury. Gliosis is where the body creates more glial cells.

Describe how the protein, growth-associated protein-43 (GAP-43), can serve as a biomarker of axon growth during development of the human nervous system.

GAP-43 is a neuronal protein that is expressed at tips of neurites (axon growth cone) during nervous system development.

Describe the relative levels of GAP-43 protein in "soft-wired" areas of adult brain. Describe the relative levels of GAP-43 protein in "hard-wired" areas of brain.

GAP-43 is constantly expressed in established axon terminals in "soft-wired" or where a lot of plasticity is observed. This includes areas of adult CNS related to learning and memory like the hippocampus and temporal lobe. GAP-43 is down-regulated in "hard-wired" areas of the adult CNS like where little plasticity is observed. This includes 1st degree motor or sensory areas.

Provide a description of proteins uniquely expressed by astrocytes that might be used to positively identify an astrocytoma brain tumor (and rule out other types of brain tumors) and/or as a biomarker for injuries to the brain.

Glial Fibrillary Acid Protein (GFAP) may act as a biomarker for TBIs, and brain tumors like astrocytoma and glioblastoma. The amount of expression of GFAP as a biomarker can help identify the presence of the injuries/tumors. The S100 protein can also be a biomarker for TBIs. It is 100% soluble in ammonium sulfate which typically causes proteins to precipitate for isolation. If there was injury to brain tissue, these cells release their cytoplasmic contents into the bloodstream. TBI can be tested for after trauma to the head by the presence/levels of these biomarkers in the bloodstream.

Identify a commonly accepted name of the "internal reticular apparatus" and briefly describe its function.

Golgi apparatus- it packages proteins into membrane-bound vesicles inside the cell before they are sent around the body.

Describe the distinguishing features between (a) Gray's type I synapse and (b) Gray's type II synapse.

Grays type I synapse includes an asymmetrical distribution of submembranous density, ~30 nm cleft width, round/large shaped neurotransmitter vesicles in the presynaptic axon terminal, and excitatory in nature at postsynaptic events. Gray's type II classification involves features including symmetrical distribution of submembranous density, ~20 nm cleft width, oval/flattened shaped pleomorphic vesicles in the presynaptic axon terminal, and inhibitory in nature at postsynaptic events.

Identify which human peripheral demyelinating disorder is modeled in animals with experimental allergic neuritis.

Guillain-Barre syndrome.

Identify the human peripheral neuropathy associated with a gene mutation in the gene coding for P0 protein.

Guillan-Barre Syndrome.

Compare characteristics of (a) "high-grade" brain tumors and (b) "low-grade" brain tumors.

High Grade- have high cellularity, are fast growing, highly malignant, and has the worst survival rates Low Grade - have low cellularity, are slow growing, are least malignant, and have the best survival rates.

Describe the congenital human disorder that arises when neural crest cells fail to properly migrate into the wall of the intestines during embryonic development

Hirschsprung's disease -(congenital aganglionic megacolon) occurs. The most distal segment of the large intestine did not have neural crest cells migrate to it so there was no formation of the myenteric or submucosal plexus. The smooth muscles cells remain contracted at the distal colon and never receive signals to relax. This leads to a large accumulation of food in the colon in need of surgical involvement

Discuss how perturbation in light activity in eyes after the "critical period" of neural development might affect width of ocular dominance columns. (b) Describe an experimental treatment that might promote structural and functional recovery from early monocular deprivation in adult rats

If there is disruption of development in the neural circuit at the critical period no changes will be experienced after the critical period resulting in permanent damage. This is because after the brain develops, there is not much growth of axons due to the inhibitory nature in the cerebral cortex from the ECM molecules. An experimental treatment that might promote structural and functional recovery from early monocular deprivation was to degrade the ECM in an animal model. That way allowing for light stimulation of a deprived column after the critical period could result in the ocular dominance columns recovery reverting back to normal and uniform.

Describe at least one proposed mechanism of action of how the drug, Copaxone (glatiramir acetate) might work to decrease sensitized T-lymphocytes from attacking central nervous system myelin in a person with multiple sclerosis.

In MS, the t lymphocytes are sensitized to the MBP. Copaxone (glatiramir acetate) is a drug that resembles myelin basic protein and is used to treat MS as it acts as a molecular decoy. The immune cells find the decoy MBP in circulation so they bind to that and don't enter the CNS and attack the myelin (which is somewhat an effective form of treatment).

Describe the reactions in a neuronal cell body of a peripheral neuron immediately following axotomy including changes in (a) relative location of the nucleus, (b) relative size of the cell body, (c) appearance of Nissl substance, (d) relative rates of cellular metabolism and protein synthesis, and, (d) relative rate of expression of immediate early genes (IEG).

In a peripheral nerve following axotomy the nucleus is eccentrically located (pushed to the side) The cell body following axotomy is swollen. The nissl substance in the soma disappears (chromatolysis). There is an increase in metabolism and protein synthesis.There also is an induction of immediate early gene (IEGs) expression. Examples of IEGs are c-fos, c-jun, and heat shock proteins.

Define the terms "internode" and "node of Ranvier" as related to a myelinated axon.

Internode- a segment of myelin that is wrapped around the axon. Node of Ranvier- the segment of axon without myelin. It contains many ion channels.

Describe some characteristics of myelin associated glycoprotein (MAG), a protein uniquely expressed by oligodendrocytes in CNS myelin.

MAG- a protein in CNS myelin. It may function as a cell-adhesion molecule between the myelin and the axon membrane during myelin wrapping. Its molecular weight is ~100,000-200,000 Da.

Describe some physical and functional characteristics of myelin basic protein (MBP), a protein uniquely expressed by oligodendrocytes in CNS myelin.

MBP- myelin basic protein in the CNS. It is found in the cytoplasmic compartment. It can also be found in peripheral myelin. It holds the cytoplasmic faces of the membrane together. Its molecular weight is 18,000 Da. It is important in the structural integrity of myelin as well as the compaction of myelin where the myelin tightens after wrapping.

Describe which major part of the human brain develops a medulloblastoma and, (b) identify the malignant cell in a medulloblastoma.

Medulloblastomas arises in cerebellum but invades the brainstem and peripheral organs. The malignant cells in medulloblastoma are the external granule cells.

Describe how metalloproteinases secreted by the axon growth cone function to allow the growth cone to migrate through the extracellular matrix found in embryonic brain tissue.

Metalloproteinases secreted by the axon growth cone are enzymes that degrade extracellular matrix proteins(laminin, fibronectin, tenascin, collagen, etc) in order to penetrate through the connective tissue. They require a metal ion cofactor to function.

Describe physical features of microtubules and list some functions

Microtubules are cylindrical tubes with a hollow core around 25 nm in diameter and made of polymerized tubulin called monomers. They are found in the cytoplasm of cells. They act as cell structural stability as well as transport material throughout cell and anchor organelles in position.

Referring to information presented in the note-pack and recorded lecture, describe characteristics about proteins expressed in peripheral nervous system myelin

Myelin Associated Glycoproteins (MAG) function as a cell-adhesion molecule useful during myelin wrapping like in the CNS. Its molecular weight is ~ 100,000 - 200,000 Da. Wolfgram Proteins 2' 3' cyclic nucleotide phosphodiesterase (CNP) is a cytoplasmic enzyme made by Schwann cells. P2 Proteins is the most abundant PNS protein constitutes about 60% of PNS myelin proteins. PMP22 Proteins or Peripheral myelin protein has a molecular weight of~ 22,000 Da. There are genetic mutations of this protein related to CMT1A (Charcot-Marie-Tooth Disease). This is a peripheral neuropathy caused by a gene mutation that effects the expression of PMP 22. P1 protein function the same as MBP in CNS myelin. They are common to both PNS and CNS myelin. It is found in cytoplasmic compartment and functions to keep both cytoplasmic faces of the membrane together. Its molecular weight is ~18,000 Da. P0 Proteins function to hold adjacent myelin membrane sheets together (similar to PLP in CNS myelin). This protein has been shown to be able to create an animal model for Guillain-Barre syndrome by inducing experimental allergic neuritis (EAN). This is where the PLP is taken from the animals PNS and injected into the animals bloodstream. Guillain-Barre syndrome is where a persons immune cells target and destroy their peripheral myelin. Mutations in the P0 gene also causes CMT1B.

Describe four proteins uniquely expressed by oligodendrocytes that might be used to positively identify a brain tumor as an oligodendroglioma (and rule out other types of brain tumors).

Myelin associated glycoproteins (MAGs), Wolfgram proteins (CNPs) made by Schwann cells in CNS Proteolipid proteins (PLP) Myelin basic proteins (MBP) which are cytoplasmic protein.

Describe the animal model of multiple sclerosis, experimental allergic encephalitis (EAE).

Myelin is obtained from the animals CNS, and is injected into the same animals bloodstream which induces a reaction against its own myelin. This reaction is similar to animal multiple sclerosis. This animal model is called experimental allergic encephalomyelitis (EAE).

Discuss some proposed mechanisms how nerve growth factor (NGF) (and its receptor) can influence the nucleus of an innervating neuron.

Nerve growth factor (NGF) is secreted by target polysynaptic cells to promote growth and support to the neuron and axon. Once bound, the ligand-receptor complex is internalized in a vesicle inside the axon terminal. Signaling events after NGF is bound may include: a rapid local signal transduction with or without receptor internalization, receptor-mediated signaling from the internalized receptor-ligand complex in the axonal terminal and during retrograde axonal transport, or the transport of second-messenger signals arising from the cascade of receptor transduction at the terminal. Besides retrograde signaling, the NGF can also cause local changes in the rate and direction of axon growth.

Describe parts of the skull that received neural crest cells during embryonic development.

Neural crest cells contribute to craniofacial bones, mandible, hyoid bone, squamous portion, palette, smooth muscles/structures in eye, stapes in the ear.

describe some neural derivatives and non-neural derivatives of neural crest found in the adult

Neural derivatives: dorsal root ganglia, sympathetic chain ganglia, pre-aortic ganglia, enteric ganglia, and sensory ganglia of cranial nerves V, VII, VIII, IX, X. Non-neural derivatives: Schwann cells, melanocytes, odontoblasts, satellite cells, cartilages, ciliary and pupillary muscles, chromaffin cells of adrenal medulla, and leptomeninges (pia and arachnoid).

Describe some neurite growth inhibitory molecules in the adult CNS: (a) located in the extracellular matrix (ECM) and, (b) located in myelin. (c) Describe how a selective Sema3A inhibitor might affect the regenerative response and functional recovery of an injured spinal cord.

Neurite growth inhibitory molecules in the adult CNS located in the ECM include tenascin, chondroitin sulfate proteoglycans (CSPG's), and semaphoring 3A. Neurite growth inhibitory molecules in the adult CNS located in the myelin include MAGs, NI-250 (Nogo A), and NI-35 (Nogo B). After injury, axons in the CNS exhibit little regeneration. It has been hypothesized inhibitors like Sema3A stop the regeneration of the axons. The selective Sema3A inhibitor could enhance the regenerative response and recovery of an injured spinal cord by stopping the expression of Sema3A.

Describe several neurotrophins (including NGF) and identify their ligand binding preferences in the trk receptor family (trkA, trkB, and trkC).

Neurotrophins (growth factors) bind to ligand receptors depending on their binding preferences. Nerve growth factor (NGF) can bind to trkA. Neurotrophin 3 (NT-3) can bind to trkB and trkC. Neurotrophin 4 (NT-4) can bind to trkB. Brain derived neurotrophic factor (BDNF) can bind to trkB as well. The binding of the growth factors stimulate axon growth and neuron survival. If this process is unable to occur, neuron death and neuron degenerative diseases like ALS are possible to arise.

Describe the source of neurotrophic molecules (a) while the axon growth cone is actively migrating and, (b) thereafter, once the growth cone establishes a connection with its target

Neurotrophins (or growth factors) are generated by the tissue the neuron is located in and the axon is growing through. While the axon growth cone is actively migrating the embryonic connective tissue is the source of the neurotrophins. Once the growth cone establishes a connection with its target, the target cell like glandular cells, skeletal muscle tissue, or postsynaptic neurons are the source of the neurotrophic molecules.

Describe the human leukodystrophy associated with a deletion in the gene that normally codes for the enzyme, arylsulfatase A

Normally, arylsulfatase A cleaves the sulfate group to break down the lipids for recycling. If there is a lack of arylsulfatase A due to a genetic defect of the gene coding for it, Metachromatic leukodystrophy is a condition where the lipids build up causing toxicity causing white matter degeneration in the CNS pulling the myelin apart.

Describe if oligodendrocytes can re-myelinate an intact axon after an episode of demyelination associated with multiple sclerosis.

Oligodendrocytes can re-myelinate as long as the axon is intact after an episode of demyelination associated with multiple sclerosis. This myelin is not the same as the originally created myelin though it is thinner and more susceptible.

Describe the (a) origin, (b) location, and (c) functional characteristics of oligodendrocytes.

Oligodendrocytes originate from neuroectoderm instead of neural crest for Schwann cells. Oligodendrocytes are located in the CNS. Once the cell finds the axon, there is an interaction between the oligodendrocytes and axon like with Schwann cells in the Oligodendrocytes function to myelinate axons of neurons in the CNS. One oligodendrocyte is able to myelinate up to ~40 different axons in the CNS.

Describe the relative degree of success in the ability of axons to regenerate following axotomy in PNS compared to CNS

PNS: displays successful regeneration of axons following injury. CNS: (brain and spinal cord) displays unsuccessful regeneration of axons follow injury.

Describe the human leukodystrophy associated with the gene mutation that normally codes for proteolipid protein.

Pelizaeus Merzbacher disease- caused by an inherited gene that effects the CNS from developing correctly leading an oligodendrocyte defect ability to produce white matter effectively which causes hypomyelination.

List the names of at least three human conditions associated with neuronal migration disorders.

Periventricular heterotopia. Lissencephaly. Double Cortex.

Describe at least one major function radial glial cells performs in the embryonic brain.

Radial glial cells provide guidance for neuronal migration during development.

Describe some risk factors associated with the formation of either rostral or caudal neural tube defects

Rostral :of vitamin A, folic acid*, riboflavin(B2), pantothenic acid, nicotinamide, and vitamin E. Caudal: Vitamin A excess, hypoxia, x-rays, and viral illness.

Identify which of the Nobel Prize winners from 1906 proposed the neuron theory and describe what the neuron theory states.

Santiago Ramon Y Cajal. This theory states that the nervous system is made up of separate nerve cells.

Identify at least one toxic material from a bacterial infection that can be transported in a retrograde trans-synaptic direction.

Tetanus can be picked up from peripheral neurons and transported in a rare retrograde trans-synaptic direction. This means the toxin diffuses backwards across the synaptic cleft. This inhibits the release of inhibitory transmitters to motor neurons causing sustained muscle contraction

Describe the cellular composition of the blood brain barrier ("bbb") with emphasis on the relative location of end-feet of astrocytes. (b) Describe some normal functions of the blood brain barrier.

The "end-feet" of astrocytes wrap around blood vessels which help to maintain the blood brain barrier. They stimulate endothelial cells to form tight junctions with the astrocytes end feet. The blood brain barrier functions to regulate what passes into or out of brain tissue which could cause inflammation or reactions leading to degeneration of tissue. This controls the environment of the brain tissue. O2, water, Co2, and nutrients are able to move across the blood brain barrier.

describe the type of signals (sensory or motor) that the central nervous system generates.

The CNS is responsible in processing information and generating motor responses/signals from the skeletal muscles, smooth muscles, cardiac muscles, and glands.

Describe the scientific utility of the Golgi stain.

The Golgi stain reveals the morphological details of individual neurons though it was mysteriously non-selective in staining neurons.

In reference to the experimental technique pioneered by Nicole LeDouarin, describe the biological utility of producing chick-quail chimeras utilizing transplantation of same-stage neural crest cells.

The biological utility of producing chick-quail chimeras utilizing transplantation of same-stage neural crest cells so that the grafted cells were able to be monitored in their migration to different tissues and structures.

Provide a concise (yet accurate) description of the major parts of a neuron focusing on (a) cell body (soma), (b) dendrites, (c) axon.

The cell body(soma) contains the nucleus and nucleolus. It is where genetic information is stored and also helps maintain the neuron's structure. The dendrites extend out from the cell body and spread electrical signals sent from the cell body. The axons extends from the cell body to make contact with other cells at a synapse.

Describe the constituent of the (a) "dark-line" and (b) "light-line" in electron microscopic images of a cross-section of myelin.

The dark-line- is the cytoplasmic major dense line. The light-line - is the extracellular intraperiod line.

Describe the relative locations of the (a) ectoderm, (b) mesoderm, (c) endoderm, (d) neural fold, (e) sulcus limitans in an early stage embryo

The ectoderm is the outermost tissue layer of the embryo. This nervous system is derived from this area. The mesoderm is the middle tissue layer where the skeleton and muscles are derived from. The endoderm is the innermost later of the embryo. The neural fold extends dorsally away from the endoderm and midline mesoderm creating a u shape. The tips of the fold fuse together forming the neural tube in the middle of the bilateral ends of the embryo. The sulcus limitans is known as the neural tube. The neural tube gives rise to the brain and spinal cord.

Describe the structures in the adult forebrain that developed from the embryonic diencephalon.

The embryonic diencephalon, formed by the prosencephalon (forebrain) goes on to form the thalamus, hypothalamus, pineal gland, and optic vesicle (retina and optic nerve).

Describe the structures in the adult midbrain that developed from the embryonic mesencephalon.

The embryonic mesencephalon forms the tectum splitting into the superion/inferior colliculus, the tegmentum creating substantia nigra and red nucleus, and the cerebral aqueduct.

Describe structure and proposed functions of filipodia and lamellipodia.

The filipodia are fingerlike processes at the end of the growth cone and lamellipodia is the webbing between the filipodia. The filipodia act as antennae and probe the surrounding environment. The lamellipodia provide force to propel the cell forward in migration.

Describe if the "g-ratio" is or is not maintained during the process of re-myelination of axons affected by multiple sclerosis.

The g-ratio is maintained during the process of re-myelination of axons affected by multiple sclerosis. The myelin area following the re-myelination however is much thinner and shorter.

Describe how the incidence of neural tube defects has changed with prenatal supplementation with folic acid

The incidence of anencephaly occurred as frequently as 1-5 in 1000 live births in the past, however dietary folic acid during pregnancy has reduced the incidence to 1 in 10000 live births.

Describe the leading theory in the biological approach to promote successful functional recovery after spinal cord injury in humans.

The leading theory in the approach to promote successful recovery after spinal cord injury in humans is to provide a few different factors. These include providing neurotrophic factors (NT-3 and/or nerve growth factor-NGF), neutralizing neurite growth inhibitory molecules w/ antibodies like IN-1 directed against NI-35 and NI-250, inhibiting the production of cytokines that mediate inflammation and gliotic scar, and to provide "bridging cells" like olfactory glia.

Describe the relative location of the longitudinal groove, sulcus limitans, alar plate, and basal plates in the embryonic rostral neural tube.

The longitudinal groove runs North and South. The sulcus limitans runs East and West dividing alar and basal plates. The alar plate is the dorsal part of the neural tube. Here there is processing of incoming sensory signals from sensory neurons in the dorsal portion of the spinal cord. The basal plate is the ventral part of the neural tube.

Describe the relative anatomical location of neural crest in embryonic brain

The neural crest is a mass of cells located just superior to the neural tube and below the overlying epidermal ectoderm. The cells appear just along most of the neural tube during vertebrae development before migrating to other structures to form them or take part in formation of other structures.

Describe (a) the normal anatomical pathway axons that project from the retina to the occipital lobe and, (b) describe the structure of an ocular dominance column found in the visual cortex in the occipital lobes of the brain.

The normal pathway axons go through the optic nerve to the optic chiasm. They then cross the neural axis to the contralateral side to the lateral geniculate nucleus of the thalamus. The signals are relayed to the cerebral cortex in the occipital lobe. Ocular dominance columns are found in the cerebral cortex of the occipital lobe. They are segregated columns of neurons in the visual cortex that receive information from each respective eye. The width of each column is relatively similar.

In reference to the intracellular or extracellular regions of a neuron, describe the relative location of the perineuronal net

The perineuronal net is a complex of extracellular matrix molecules interposed between a meshwork of glial cell processes and nerve cell surfaces. It is on the outside of the cell.

Identify relative growth rate of a regenerating peripheral nervous system axon following axotomy

The relative growth rate of regenerating PNS axon is 1-2 mm/day (roughly 1 in/month). Clean cuts also recover better than messy cuts.

Describe the structures in the adult hindbrain that developed from the embryonic metencephalon and myelencephalon.

The rhombencephalon (hindbrain) further divided into the metencephalon which is responsible for the formation of the cerebellum, pons, 4th ventricle. The hindbrain also divided to form the myelencephalon which is responsible for creating the medulla oblongata.

Identify a commonly accepted name of Nissl bodies and describe their function.

The rough endoplasmic reticulum- decodes messages allowing for new protein assembly.

Describe features associated with (a) semi-lobar holoprosencephaly, (b) alobar holoprosencephaly, and (c) anencephaly.

The semi-lobar form of holoprosencephaly is characterized by a small cleft representing an attempt to separate the hemispheres. There is no gyral pattern and a grave condition involving minimal if any brain function. Alobar holoprosencephaly is where a large single vesicle inside a single hemisphere is seen. There was no division of hemispheres. Anencephaly is a malformation of the anterior part of the neural tube. Forebrain development is disrupted and all that remains is the area cerbrovasculosa, a flattened remnant of disorganized brain tissue.

List several structures in the adult forebrain that develop from the embryonic telencephalon

The telencephalon differentiates into the olfactory bulb, cerebral cortex, basal ganglia, corpus callosum, cortical white matter, and internal capsule.

Briefly describe the transient zones of neurons formed during neuronal migration observed in the embryonic telencephalon which, eventually, forms the six-cell-layered cerebral cortex.

The telencephalon is single layered but during development the telencephalon becomes multilayered. In the center of the telencephalon is a hollowed fluid filled space called a ventricle. The layer closest to the ventricle is called the subventricular zone (sub VZ) containing glial cells and primitive neurons. The astrocyte called the radial glial cells extends processes from the next layer, the ventricular zone (VZ) to the cortical plate region serving as a guide of the migration of the neuroblasts from the VZ to form the multilayered cerebral cortex. The second layer, the pre-plate (PP) contain the first neurons. The axons as well as thalamus ingrowing axons establish the intermediate zone (IZ). The generated neurons of cortical layers 2-6 establish the cortical plate (CP). These split the PP into the marginal zone (MZ, future layer 1), and the subplate (SP) containing neurons. After the neuronal migration/differentiation, there are 6 layers visible overlying the white matter. The subplate mostly disappears.

Describe how the shape of the neural folds change over time to form the neural tube. Describe the relative location of the (b) superior neuropore, (c) inferior neuropore in regards to either the rostral ("toward the head") or caudal end of the neural tube

The two halves of the neural plate, called neural folds extended dorsally, away from the endoderm and midline mesoderm. Eventually the tips of the folds fuse to form a tube with two open ends. Later, the ends of the tube called neuropores fuse to produce a completely closed neural tube. The superior neuropore is on the rostral (cranial) end of the neural tube. The inferior neuropore is on the caudal end of the neural tube.

Describe how the three primary brain vesicles form into the five brain vesicles appearing in a later stage embryo. In your discussion, be sure to name the five brain vesicles.

These three brain vesicles form the five brain vesicles existing during the 6th week of development. The prosencephalon (forebrain) further divides forming the telencephalon and diencephalon. The mesencephalon (midbrain) does not further divide. The rhombencephalon (hindbrain) divides into the metencephalon, and myelencephalon.

Describe characteristic features of (a) thick, (b) intermediate, and (c) thin cytoskeleton filaments.

Thick filaments are made up of myosin fibrils and are around 15 nm in diameter. Intermediate filaments also called "neurofilaments" vary to about 7-11 nm in diameter. They are insoluble and very durable over time providing structural integrity. Thin filaments also called "microfilaments" are around 7 nm in diameter. They are composed of 2 intertwined actin filaments and serve to anchor the cell membrane to the cytoskeleton.

When cultured in the absence of glial growth factor (GGF2), describe the percentage of neural crest cells that differentiate into neurons and glial cells and, (b), when cultured in the presence of glial growth factor (GGF2), describe the percentage of neural crest cells that differentiate into neurons and glial cells.

When cultured in the absence of GGF2, the majority of growth was seen in neurons instead of glial cells. When cultured in the presence of GGF2, the ratio of neurons to glial cells favored showing GGF2 promotes glia and suppresses neuron development.

Describe the color change to gray matter of brain and/or spinal cord tissue when soaked in copper sulfate.

When soaked in copper sulfate, gray matter of the brain turns blue while white matter does not change.

Identify the neurodevelopmental disorder presented in the recorded lecture (from Nature, 2016) that shows morphological changes of Golgi-stained cortical neurons.

Williams syndrome shows the morphological changes of Golgi-stained cortical neurons. The neurons visualized with the golgi stain have extensive arborization.

Describe some characteristics of CNP, a protein uniquely expressed by oligodendrocytes in CNS myelin.

Wolfgram Proteins (2' 3' cyclic nucleotide phosphodiesterase/CNP) are cytoplasmic enzymes. They are made by oligodendrocytes therefore can be used as biomarkers for oligodendrocytes. Since oligodendrocytes create myelin which makes white matter, it can also be used as a biomarker for myelin as well. If needing to identify a cell type in a tumor for example an oligodendroioma, the tissue can be found can be CNP positive or negative indicating if the tumor is an oligodendroioma. Without CNP in animal models, the oligodendrocyte loses its trophic properties in supporting the axon and the axon eventually dies leading to degeneration of the neuron. This shows CNP is importance in the cell.

differentiate between the conditions of meningohydroencephalocele.

a defect in the occipital bone where the meninges, brain tissue, and ventricles bulge through the opening in the Cranial region.

Briefly describe gene mutations, gross features, and histological features found in the brains of people diagnosed with Periventricular heterotopia

a genetic mutations in FLN1 in females on one X chromosome. A normal FLN1 gene migrates to the cortical plate while the mutant cells have a defect in their ability to migrate from the ventricular zone. In the adult, the result is a collection of periventricular heterotopic neurons lining the lateral ventricle resulting in epilepsy.

In reference to synaptic connections on dendritic spines, describe the relative position of (a) excitatory synapses and (b) inhibitory based on localization on either the shaft or head of the spine

excitatory synapses are more likely to form points of contact on the head of dendrite spine. inhibitory synapses are more likely to form points of contact on the shaft of dendrite spine.

Provide the name of the drug used to reveal presence of neurofibrillary tangles in the brain of a living person with Alzheimer's disease

flortaucipir 18

Describe the location and functional characteristics of satellite cells in the peripheral nervous system

found in the dorsal root ganglia and function to support neuronal cell bodies there. They also do not make myelin.

Describe the factors being compared in the "g-ratio" and (b) identify at least one protein that regulates the g-ratio in normal range.

g-ratio: compares axon diameter x myelin width. neuroregulin- a protein that can regulate the g-ratio If there is overexpression of neuroregulin causes an increase in g-ratio with thicker myelin.

Describe the influence of the notochord in dorsoventral patterning in the early stage embryo. In your discussion, identify a soluble factor released by the notochord to influence the developmental fate of cells in the ventral neural tube.

he notochord is a cartilaginous skeletal rod supporting the body in all embryonic and some adult chordate animals. It is deep to the ectoderm at the midline. The notochord releases factors causing invagination of the embryo in order to form the neural tube. The notochord expresses sonic hedgehog (SHH) which induces the differentiation of the floor plate and motor neurons in the adjacent ventrolateral region of the neural tube.

Describe at least one function ascribed to chondroitin sulfate proteoglycan (CSPG) in the adult central nervous system

impedes formation of new or unnecessary synapses in adult nervous system.

Describe the type of signals (sensory or motor) that the central nervous system receives

information from somatic, visceral, and special sensory receptors.

Describe a technique that increases spine density in striatal neurons in a mouse model of Parkinson's disease.

intensive treadmill exercising. It has been shown to reverse dendritic spine loss.

Briefly describe gene mutations, gross features, and histological features found in the brains of people diagnosed with double-cortex

involves mutation of DCX gene on the x chromosome so half of the cells are normal and half have the mutation. Normal neuroblast cells are able to migrate to the cortical plate and the mutant cells have a defect in the migration process. In adults, the result is a normal outer cortex and a band of heterotopic neurons in the subcortical white matter.

differentiate between the conditions of meningomyelocele ("cystic spina bifida")

is a type of spina bifida is where the meninges and spinal cord bulge through opening.

Describe several proteins in the extracellular matrix (ECM) that influence axon growth cone migration in the developing human nervous system.

laminin, fibronectin, tenascin, collagen, netrin, and chondroitin sulfate proteoglycan. These proteins work to stimulate axon growth.

Describe the location and functional characteristics of Schwann cells that do not make myelin.

located in the PNS. In the PNS, the schwann cells function to support and ensheathe unmyelinated axons. They are smaller in diameter and conduct slower impulses.

Describe two types of axons based on whether (a) myelin is present or (b) myelin is not present.

myelinated axon- myelin is composed of lipid and protein rich membrane from different cells. The membrane is made up of cells like an oligodendrocyte from the CNS or a Schwann cell if the neuron is from the PNS. With a myelinated axon, the action potential is able to travel quicker than the unmyelinated axon because the myelin insulates the action potential. unmyelinated axon- there are no nissl bodies (rough endoplasmic reticulum) at the axon hillock. Different materials are sent away from the cell body like organelles and vesicles. A retrograde direction of transport is also possible traveling towards the cell body.

Identify the cytoskeletal protein that might serve as a recently identified biomarker of Alzheimer's disease.

neurofilament light chain protein (NfL).

Describe a unique characteristic regarding distribution of Nissl bodies in neurons.

nissl bodies are seen in cell body and dendrites, but NOT at the axons.

Describe the genetic mutation responsible for William's syndrome and, (b) describe some derangements in their brain cytoarchitectonics

on chromosome 7 band 7q11.23 is deleted in Williams Syndrome. derangements of the brain cytoarchitectonics include marked indentation of the temporo-parietal regions, a smaller amygdala (responsible for fear inhibition), and their central sulcus ends before reaching the midline.

Describe a unique characteristic regarding distribution of MAP2 in neurons.

only found in dendrites.

Describe the (a) origin, (b) location, and (c) functional characteristics of Schwann cells that make myelin

originate from neural crest (neurological tissue) that exist temporarily during development. migrate from the neural crest and are located in the PNS. Schwann cells that make myelin are single cells that make a chain on the axon. A single Schwann cell wraps itself ~20x on a region of the axon. The Schwann cell and axon interact and bond together.

Describe reasons a scientist would employ the technique of "immunocytochemistry" of brain tissue.

to visualize the presence of a specific protein or antigen in a cell by using a specific antibody that will bind to it.

differentiate between the conditions of meningocele,

where the neural tube does not close properly at the caudal end, the CNS/covering may bulge through the opening. This type of spina bifida is where the meninges bulge through the opening.