Term
| cerebellum receives input from vestibular system via which peduncle and to what part of the cerebellum does it end? |
|
Definition
| inferior peduncle, vestibulocerebellum |
|
|
Term
| cerebellum receives input from muscle afferents in the spinal cord via which peduncle and which area of the cerebellum does it end? |
|
Definition
| inferior peduncle, spinocerebellum |
|
|
Term
| cerebellum receives input from somatic sensory and motor areas of cerebral cortex via which peduncle? and where does it end? |
|
Definition
| via middle peduncle; cerebrocerebellum |
|
|
Term
| cerebellum receives 3 return signals. from what? and via which peduncles? |
|
Definition
| vestibular system via inferior; spinal cord via superior as relayed via reticular formation; motor cortex via superior as relayed via thalamus |
|
|
Term
| what are the 3 cerebellar deep nuclei? |
|
Definition
| dentate nucleus, interpositus nucleus, and fastigial nucleus |
|
|
Term
| ventral lateral nucleus of thalamus projects to? |
|
Definition
| area 4, primary motor cortex |
|
|
Term
| ventral posterior nucleus of thalamus projects to? |
|
Definition
| areas 3, 1, 2, primary somatic sensory cortex |
|
|
Term
| ventral anterior nucleus of thalamus projects to? |
|
Definition
| connects basal ganglia system to the premotor areas |
|
|
Term
| as a whole, the basal ganglia are functionally involved in? |
|
Definition
| initiation and suppression of movement |
|
|
Term
| what 4 specific thalamic nuclei project to and receive from areas of association cortex? |
|
Definition
| lateral posterior, pulvinar, dorsomedial, and anterior (tubercle) |
|
|
Term
| what do the lateral posterior nucleus and pulvinar connect? |
|
Definition
| pretectum/superior colliculus to the parietal and temporal lobe assoc. cortex - provide transthalamic routes for coritco-cortical communication |
|
|
Term
| what does the pretectum do? |
|
Definition
| controls the size of pupils, helps in measuring the size and motion of objects (approaching vs. receding etc) |
|
|
Term
| what does the superior colliculus do? |
|
Definition
| sends data to thalamus that helps in ID the location of objects in space, uses visual, auditory and somtaic sensory input to change the direction of gaze |
|
|
Term
| dorsomedial nucleus - where does it receive input from and where does it project to? |
|
Definition
| receives from basal ganglia, amygdala; projects to prefrontal association cortex |
|
|
Term
| where does the anterior nucleus of the thalamus project to? where does it receive in put? |
|
Definition
| receives subcortical input from mammillary bodies via mammillo-thalamic tract and subcortical input from subdivisions of the limbic lobe including hippocampus; projects to "limbic lobe" (runs thru cingulate gyrus) |
|
|
Term
| what are the 3 parts of the subthalamus? |
|
Definition
| thalamic reticular nucleus, subthalamic nucleus, zona incerta |
|
|
Term
| describe the interaction b/w subthalamic nucleus and globus pallidus. |
|
Definition
| globus pallidus externa projects into subthalamic nucleus (via axons passing across the internal capsule) and the globus pallidus internus receives return input from subthalamic nucleus |
|
|
Term
| where could i find the nuclei for CN III? |
|
Definition
| close to the midline, just ventral to the cerebral aqueduct at the transverse level of the superior colliculus. fibers travel ventrally thru tegmentum to emerge in the medial walls of the interpeduncular fossa |
|
|
Term
| where could i find the nucleus for CN IV? |
|
Definition
| nucleus close to midline right below the CN III nucleus, close to midline, just ventral to cerebral aqueduct at the transverse level of the inferior colliculus - fibers sent DORSALLY to emerge @ lower border of inferior colliculus |
|
|
Term
| where could i find the nucleus for VI? |
|
Definition
| close to midline in the pontine tegmentum, emerges ventrally below the lower border of the pons, along lateral border of the pyramids |
|
|
Term
| where could i find the nucleus for CN XII? |
|
Definition
| (long strip) close to midline @ dorsal side of medullary tegmentum extending from upper end of open medulla to the lower level of the closed medulla. fibers emerge in pre-olivary sulcus |
|
|
Term
| where could i find the nucleus for CN V? |
|
Definition
| in pontine tegmentum, around same level as CN VI, but more laterally displaced and much closer to ventral side of tegmentum. fibers emerge on lateral side of ventral pons (thick) |
|
|
Term
| where could i find the nucleus for CN VII? |
|
Definition
| in pontine tegmentum below the nucleus for CN V, also laterally displaced and close to the ventral side of the tegmentum. fibers emerge sub-pons just laterally to CN VI |
|
|
Term
| where could i find the nucleus for CN IX, X, XI? |
|
Definition
| (long) @ same transverse level as nucleus for XII except more laterally displaced and slightly more ventral. fibers emerge in post-olivary sulcus |
|
|
Term
| what 5 things are controlled by reticular formation? |
|
Definition
| arousal and wakefulness, spinal cord reflexes, coordinated eye movements, cardiovascular reflexes, respiratory center |
|
|
Term
| where are acoustic tubercles found and what do they house? |
|
Definition
| at lateral end of stria medullaris of the IVth ventricle (near foramen of luschka), house dorsal cochlear nuclei |
|
|
Term
| what are the 3 parts of substantia nigra? |
|
Definition
| pars compacta, pars reticularis, ventral tegmental area (far medially and ventrally, belongs to the limbic system, has fibers running up to pre-frontal region of cerebral cortex) |
|
|
Term
| what is the solitary tract of V? |
|
Definition
| travels w/the spinal tract of V, is the internal continuation of the taste fibers and thoracic/abdominal afferents if VII, IX, and X |
|
|
Term
| striatum receives major input from? and projects to? |
|
Definition
| input from cerebral cortex, dorsal thalamus, and substantia nigra; output to globus pallidus and substantia nigra |
|
|
Term
| what cells are the only source of cholinergic innervation to the hippocampal complex? |
|
Definition
|
|
Term
| what is the basal nucleus of Meynert? |
|
Definition
| part of anterior perforated substance, projects to cerebral cortex, uses AcH as neurotransmitter - undergoes degeneration in Alzeimer's dementia (only source of cholinergic axons to neocortex) |
|
|
Term
| what is the diagonal band of broca? |
|
Definition
| collection of cholinergic neurons running along medial border of anterior perforated space, send axons to olfactory bulb |
|
|
Term
| hippocampus can be divided into 3 parts |
|
Definition
| dentate gyrus, hippocampus, and subiculum |
|
|
Term
| what's degenerated in parkinson's disease? |
|
Definition
| pars compacta (secretes dopamine) |
|
|
Term
| cyotoskeleton of neuron has microfilaments, structure? |
|
Definition
| double stranded helix of actin monomers concentrated in periphery of cell |
|
|
Term
| cytoskeleton of neuron has neurofilaments, structure/proteins? |
|
Definition
| 24 twisted monomers of cytokeratin - present throughout neuron particularly in axon |
|
|
Term
| cytoskeleton has microtubules. structure? proteins? |
|
Definition
| polarized helical tube formed of alpha and beta tubulin subunits. present throughout cell, esp in axons - in cell body and dendrites poles organized at random. in axon, + ends are all pointed away from soma |
|
|
Term
| 2 ways myelin increases conduction velocity |
|
Definition
1. increases resistance of membrane --> decreases local circuit current leakage --> allows current to depolarize at a greater distance
2. decreases capacitance that must be charged as depolarization occurs in the axon membrane ahead of the propagating AP |
|
|
Term
| axo-dendritic synapses are often what? |
|
Definition
| excitatory (glutamatergic); gray type 1 (more pre- and esp more post-synaptic density "asymmetrical" densities are partly microfilaments); large active zone, round vesicles, wide cleft |
|
|
Term
| axo-somatic synapse is often? |
|
Definition
| inhibitory (GABAergic); gray type II (small active zone, flat vesicles, narrow cleft, less pre and postsynaptic density "symmetrical" |
|
|
Term
| describe the 3 transport systems present in the BBB. |
|
Definition
1. GLUT1 - transports glu into brain, not insulin-sensitive
2. AA carrier sys - carries leu, phe, and other AA & L-DOPA - uses facilitated diffusion
3. A system (small AA system) - active transport sys uses Na gradient to pump Gly out of brain - separate transport sys for basic, acidic, monocarboxylic and other AA |
|
|
Term
| whats the significance of the arachnoid layer? |
|
Definition
| has tight junctions blocking free diffusion between brain and other tissues of the body (barrier b/w ECF and CSF) |
|
|
Term
| one type of sensory mechanism: site of channels sensitive to adequate stimulus and site of AP generation on same cell. where does this mechanism occur? |
|
Definition
| free nerve endings in skin, paccincian corpuscles, muscle spindles, golgi tendon organs, joint receptors, baroreceptors, osmoreceptors, all of which are mechanically sensitive. and temp results in skin and ant hyp |
|
|
Term
| mechanism of sensation: channels sensitive to mechanical deformation are in one cell and AP are generated in another cell. where does this happen? |
|
Definition
| some cutaneous receptors, all auditory and vestibular receptors |
|
|
Term
| sensory mechanism: chemicals affect a transmembrane receptor (G protein-mediated). where does this mechanism occuR? |
|
Definition
1. some sensory receptor cells can generate AP themselves (olfaction)
2. others release synaptic transmitters affecting other neurons that generate AP (taste, paO2, paCO2) |
|
|
Term
| describe the 4th sensory mechanism (for eyes) |
|
Definition
| photons activate photopigments --> activates transducers --> activates PDE --> hydrolyzes GTP --> closes Na channels --> hyperpolarization --> decreased transmitter release --> decreased rate of AP firing |
|
|
Term
| Ia afferents are _____ while II are ____? |
|
Definition
| Ia are fast adapting and slow adapting; II do not adapt at all |
|
|
Term
| what induces exocytosis of neurotransmitter vesicles? |
|
Definition
| increased [Ca] comes into presynaptic terminal and binds to synaptotagmin in release site complex and triggers it |
|
|
Term
| what causes EPSPs (depolarizations of postsynaptic membrane) in neurons? |
|
Definition
| increases in both gNa and gK with a reversal potential near zero; OR solely due to a decrease in gK |
|
|
Term
| what causes IPSPs (hyperpolarizations of postsynaptic neuron)? |
|
Definition
| increases in gCl and/or gK |
|
|
Term
| whats the diff b/w ionotropic receptors and metabotropic receptors? |
|
Definition
| ionotropic = fast, ligand-gated channels; metabotropic = slow, g-protein mediated may affect channels indirectly thru second messengers like cAMP etc |
|
|
Term
| what are some examples of glutamatergic ionotropic receptors? |
|
Definition
|
|
Term
| excitatory synapses tend to be located on what part of neuron? |
|
Definition
| dendrites or spines that emerge on dendrites, rarely cell body |
|
|
Term
| how does inhibition work with GABA and Gly? |
|
Definition
| gaba-a and gly receptors open a channel that has selective conductance to chloride --> small hyperpolarization --> IPSP (gaba-b are metabotropic, same mechanism, just takes longer) |
|
|
Term
| inhibitory synapses tend to be located on what part of neuron? |
|
Definition
| cell body (often but not always) |
|
|
Term
| extensive dopaminergic innervation in what 2 areas of cns? and what discrete nuclei gave rise to this? |
|
Definition
| striatum & frontal lobe of cortex; from substantia nigra and ventral tegmentum |
|
|
Term
| extensive norepi distribution in cns, origin? |
|
Definition
|
|
Term
| peptides have diverse functions in cns. what are opioids involved in? |
|
Definition
| pain control (enkephalin, b-endorphin, dynorphpin) natural analgesics/spinal cord, central gray, midbrain) |
|
|
Term
| peptide hormone substance p does what? |
|
Definition
| involved in transmission of pain/primary sensory afferents) |
|
|
Term
| what is the rate limiting step in dopamine synthesis? and what are the details of this step |
|
Definition
| tyrosine hydroxylase - converts l-tyrosine to l-dopa. oxidation reaction - uses oxygen and requires pteridine cofactor (reoxidized by pteridine reductase) |
|
|
Term
| what affects TH enzyme activity? |
|
Definition
| substrate concentration, concentration of end product inhibitor |
|
|
Term
| what does dopamine decarboxylase do and where is it? |
|
Definition
| converts dopamine to NE, located in membrane and cytosol of storage vesicles themselves |
|
|
Term
| for catecholamines how is rate of NT synthesis coupled to rate of release? (3 ways) |
|
Definition
1. can exacerbate signal by blocking reuptake
2. increase synthesis of NE by removal of negative feedback (NE and dopa) on Tyrosine hydroxylase or allosterically activating TH (buildup of presynaptic cAMP and TH becomes allosterically modified so TH has greater affinity for tyr and reduced affinity for endproduct inhibitors)
3. induce synthesis of new TH and DBH molecules (this is long term adaptation) |
|
|
Term
| broadly speaking, what 2 events in a synapse are regulated by Ca? |
|
Definition
| release of the vesicle from cytoskeleton and fusion of the vesicle with plasma membrane |
|
|
Term
| how is Ca involved in releasing vesicles from the cytoskeleton? |
|
Definition
| vesicle encased in synapsin, which binds to actin cytoskeleton, inhibiting vesicle movement. CAM kinase is a protein inside the vesicle that has synapsin tail sitting on it. Ca comes in --> CAM kinase activated to phosphorylate synapsin --> synapsin dissociates from vesicle and breaks apart from actin --> vesicle free to move around |
|
|
Term
| how is Ca involved in helping vesicles fuse w/membrane? |
|
Definition
| synaptotagmin is located near Ca channel --> Ca rushes in --> synaptotagmin senses local increase in Ca and this influences its ability to facilitate diffusion of 2 separate lipid membranes |
|
|
Term
| what structures are included in allocortex? |
|
Definition
| cingulate gyrus, parahippocamal gyrus, uncus, olfactory cortex, olfactory bulb (paleocortex= base of telencephalon; archicortex= hippocampus) |
|
|
Term
| what are the 6 layers of lamination in neuronal cell types and what kind of cells do they mostly have in them? |
|
Definition
1. molecular layer (cell-poor neuropil)
2. external granular (small pyramidal)
3. external pyramidal (medium pyramidal)
4. internal granular (small non-pyramidal)
5. internal pyramidal (large pyramidal)
6. multiform (large non-pyramidal, fusiform-shaped modified-pyramidal cells) |
|
|
Term
| principal neurons/projection neurons are mostly located in which layers? while interneurons or short axon cells populate which layers? |
|
Definition
| 2, 3, 5, 6 (make up 80% of cortex); 2, 3, 4, 5 (20%) |
|
|
Term
| all short axon cells are inhibitory (use GABA) except what one kind of cell? |
|
Definition
| spiny stellate cell - uses glutamate |
|
|
Term
| which cortical layer receives input from thalamus? |
|
Definition
|
|
Term
| which cortical layer sends output to subcortical structures other than thalamus? |
|
Definition
|
|
Term
| which cortical layer sends output to thalamus? |
|
Definition
|
|
Term
| where do afferents from specific thalamic nuclei end (layer)? |
|
Definition
| end as dense arborization in layer 4 |
|
|
Term
| where do fibers from non-specific thalamic nuclei end (what layer)? |
|
Definition
| terminate diffusely along their course, mostly in layer 6 |
|
|
Term
| where do afferents from other cortical areas (association axons and commissural axons) end? (layer) |
|
Definition
| terminate diffusely along their course mostly in layers 2 and 3 |
|
|
Term
| what layer(s) of the cortex are the major source of cortico-cortical fibers? |
|
Definition
|
|
Term
| what is the basic 3 layer structure of allocortex? |
|
Definition
1. molecular layer (cell poor neuropil)
2. principal cell layer (pyramidal cells)
3. multiform/polymorphic layer (non-pyramidal cells) |
|
|
Term
| damage to brocas area vs wernickes area |
|
Definition
brocas area damage --> expressive aphasia (can comprehend but cannot express)
wernickes area damage --> receptive aphasia (can talk, but it doesnt make sense and they don't comprehend...lose their language) |
|
|
Term
| interruption of anterior cerebral blood flow can cause what? |
|
Definition
| contralateral hemiplegia (paralysis of the lower limbs |
|
|
Term
| occlusion of middle cerebral artery would cause? |
|
Definition
| contralateral hemiplegia most marked in upper extremities and face, aphasia when its the left hemisphere |
|
|
Term
| posterior cerebral arteries end in which 2 arteries/ |
|
Definition
| calcarine and parietooccipital aa. |
|
|
Term
| which artery travels with CN VII and VIII? |
|
Definition
|
|
Term
| which a supplies the flocculus? |
|
Definition
| anterior inferior cerebllar a (also supplies ant and inf cerebellar hemispheres,middle cerebellar peduncle, and choroid plexus of IV) |
|
|
Term
| what does recurrent a of huebner supply? |
|
Definition
| comes off ant cerebral artery (aka medial striate artery) and supplies rostro-medial head of caudate, putamen, ant limb of internal capsule |
|
|
Term
| what aa supplies sup and inf colliculi? |
|
Definition
| quadrigeminal branch of posterior cerebral arter |
|
|
Term
| whats the anastomotic pathway called in the spinal cord? |
|
Definition
|
|
Term
| where do medial striate aa come from and what do they supply? |
|
Definition
| branch off of anterior cerebral aa. and supply rostromedial head of caudate, putamen, and anterior portion of internal capsule |
|
|
Term
| where do anteromedial branches come from and what do they supply? |
|
Definition
| come from anterior cerebral arteries and pass thru anterior perforated space to supply parts of anterior hypothalamus, preoptic and supra chiasmic regions |
|
|
Term
| where do lateral striates originate and what do they supply? |
|
Definition
| they are central branches of middle cerebral artery, pass thru anterior perforated space to supply cuadate, putamen, internal capsule, and globus pallidus |
|
|
Term
| where do anterior choroidal aa originate and what do they supply? |
|
Definition
| branch of the ICA, travels along optic tract, enters inf horn of lat ventricle via choroid fissure, supplies choroid plexus of inf horn, optic tract, uncus, amygdala, hippocampus, ventral globus pallidus, tail of caudate, retrolenticular and sublenticular portions of internal capsule (prone to thrombosis) |
|
|
Term
| where do posteromedial branches originate and what do they supply? |
|
Definition
| come from posterior communicating aa and posterior cerebral aa, pass thru posterior perforated space, supply hypophysis, infundibulum, tuber cinerum, mammillary bodies, interpeduncular fossa, ant and med thalamus, subthalamic regions, midbrain tegmentum |
|
|
Term
| where do posterolateral/thalamogeniculate aa originate and waht do they supply? |
|
Definition
| posterior cerebral aa, supply posterior portion of thalamus, pulvinar, lateral nuclei of thalamus, LGB and MGB |
|
|
Term
| where does posterior choroidal art originate and what does it supply? |
|
Definition
| posterior cerebral artery: medial branch supplies choroid plexus of 3rd ventricle, atrium of lat ventricles, sup and med nuclei of thalamus, pineal, parts of midbrain tectum; lateral branch anastamoses with ant choroidal art to supply choroid plexus of 4th ventricle |
|
|
Term
| what protein do we test for to check for defects i neural tube closure? |
|
Definition
|
|
Term
| what are the 4 types of spina bifida? |
|
Definition
| occulta (lack of vertebral arch fusion, cord still in vertebra); meningocoele (cord still in cavity but meninges outpocketing); myelomeningocele (meninges AND cord outpocketing); myeloschisis (neural tube never fused) |
|
|
Term
| what forms the inferior olivary nucleus? |
|
Definition
| gray matter from alar plates! |
|
|
Term
| what structures are derived from the alar plate? |
|
Definition
| nucleus cuneatus, nucleus gracilis, spinal nucleus of V, trigeminal nuclei, vestibulo-cochlear nuclei, tectum |
|
|
Term
| what structures are derived from the basal plate? |
|
Definition
| dorsal motor nuclei, ventral motor nuclei, hypoglossal nuclei, abducens nuclei, oculomotor nuclei |
|
|
Term
| where is the cerebellum from developmentally? |
|
Definition
| forms from the rhombic lip which is an alar plate derivative |
|
|
Term
| where is the corpus striatum from developmentally? |
|
Definition
| ganglionic eminence (--> amygdala, putamen, caudate) |
|
|
Term
| where is globus pallidus from developmentally? |
|
Definition
| neurons from diencephalon migrate laterally to form it. |
|
|
Term
| neuronal development in brainstem (nuclei organization): where do you find the older neurons vs newer ones? |
|
Definition
| outside-inside pattern of neuronal development (new ones more medial, old ones more lateral) |
|
|
Term
| neuronal development in cerebral cortex (laminar organization): where do you find the old vs new ones? |
|
Definition
| inside-outside sequence of generation: younger cells closer to pia, older cells closer to neuroepithelium |
|
|
Term
| what does the Hes gene do and what happens when its inhibited? |
|
Definition
| Hes genes delay the differentiation of neuronal precursor cells into neurons --> increase in pool of precursor cells (by proliferation). inhibition of Hes --> premature differentiation of neuroblasts and depletion of the neuronal pool, absence of late born neurons |
|
|
Term
| where do projection neurons and local circuit neurons come from? (what layer) |
|
Definition
| projection neurons come from ventricular/subventricular zone; local circuit neurons 65% come from vz/svz, 35% come from ganglionic eminence |
|
|
Term
|
Definition
| gene, that when turned on, inhibits the default pathway to creating CR neurons and induces neurons to differentiate into neurons of other layers. when this gene is off, layers will all be of CR neurons, no differentiation into other types |
|
|
Term
| describe the role of bmp and shh in dorsal ventral polarity establishment. |
|
Definition
| default pathway is to form a neural tube, this pathway is inhibited by BMP, so SHH inhibits an inhibitor. (notocord produces SHH and ectoderm produces BMP. BMP ends up in roof plate, SHH induced in floor plate) |
|
|
Term
| what determines the differentiation of neurons into diff types in the ventral spinal cord? |
|
Definition
| interaction of the diff concentrations of SHH with the transcription factors that are expressed in diff types of neurons (ie ones closer to floor plate --> exposed to higher levels of SHH --> motor neurons) |
|
|
Term
| oligodendrocytes develop in region of ____ SHH while astrocytes develop in area of ____ SHH |
|
Definition
|
|
Term
| neuromeres: one defines the isthmus (between mes and met) and is associated with? |
|
Definition
|
|
Term
| the six neuromeres of the rhombencephalon regulate what? |
|
Definition
| rostro-caudal level of generation of the cranial nerve nuclei |
|
|
Term
| what does the 4th prosomere do? |
|
Definition
| a. derives the hypothalamus b. derives the cerebral hemispheres c. derives the retina |
|
|
Term
| what does the 3rd prosomere derive? |
|
Definition
| ventral thalamus/subthalamus |
|
|
Term
| what does the 2nd prosomere derive? |
|
Definition
|
|
Term
| what does the 1st prosomere derive? |
|
Definition
|
|
Term
| where are the 4 organizing centers in the developing neural system? |
|
Definition
| b/w 2nd and 3rd prosomeres, b/w 1st prosomere and mesencephalon; between mesencephalon and isthmus; b/w myelencephalon and spinal cord |
|
|
Term
|
Definition
| help establish apico-caudal polarity in hindbrain and spinal cord (mutations alter the position of cranial nerves or prevents their formation) expression of diff hox genes specifies which CN nuclei is going to form in the brainstem |
|
|
Term
| what is the lamina terminalis derived from embryologically? |
|
Definition
|
|
Term
| what is GFAP (glial fibrillary acidic protein)? |
|
Definition
| neural stem cells generate neurons first then glial cells. the promoter region of glial specific genes (GFAP) are silenced (highly methylated) in neural stem cells during early dev, making the cells refractory to inductive signals for astrocyte dev). as dev proceeds, GFAP demethylated and neural stem cells can become astrocytes |
|
|
Term
| defects in neuronal migration initiation (i.e. periventricular heterotopia) associated with what cause? |
|
Definition
| mutations that disrupt cytoskeletal associated proteins |
|
|
Term
| defects in ongoing neuronal migration (i.e. lissencephaly) are associated with what cause? |
|
Definition
| mutations in microtubule-associated proteins |
|
|
Term
| defects in signals that stop migration (i.e. cobblestone lissencephaly) are associated with what causes? |
|
Definition
| alterations in protein glycosylation |
|
|
Term
| why are cortical dysplasias epileptic? |
|
Definition
| cortical dysplasia = abn dev of columnar clones; derived from ventricular zone but lack component from ganglionic eminence (therefore neurons are glutaminergic and highly epileptic) |
|
|
Term
| while hox genes determine apico-caudal polarity in rhombencephalon, what establishes this polarity in the mesencephalon? |
|
Definition
| 3 organizing centers (mes/met boundary (MHB_, floor plate, anterior neural ridge. these centers est. an epigenic grid and neural and glial progenitors assume distinct fates according to this grid (i.e. dopaminergic neurons rostral to mhb and serotoninergic neurons caudal to it) |
|
|
Term
| what is the zona limitans intrathalamica? |
|
Definition
| separates the dorsal thalamus from the subthalamus, is one example of an organizing center present in the prosencephalon to help establish apico-caudal polarity |
|
|
Term
| what proteins in the EC matrix interact w/the receptor cells on the growth cone? (and what is the receptor cell) |
|
Definition
| receptor cell = integrins. integrins interact with collagen, laminin, fibronectin |
|
|
Term
| cell surface adhesion (bw growth cone and target tissue) mediated by what 2 groups of cells? |
|
Definition
| cadherins (req ca), and cell adhesion molecules (CAM) do not req ca |
|
|
Term
|
Definition
| attractant for commisural axons in the ventral floor plate. (is a chemoattractant along with SHH) |
|
|
Term
| what is an ex of a chemorepellent? |
|
Definition
|
|
Term
| describe the slit/nectin system |
|
Definition
| slit binds to receptor robo1 and acts as chemorepellent. robo3 blocks robo1 action --> slit cannot bind --> netrin receptor activated--> axon starts to cross midline--> once crossed, robo1/chemorepellent activated again so axon moves away |
|
|
Term
| what process are WNTs involved in? |
|
Definition
| migration of commissural axons from posterior to anterior (of the floor plate/ventral) more WNT4 in anterior than post (gradient) and axons move twd higher gradient of WNT4 |
|
|
Term
| explain the chemoaffinity theory. (ephrin) |
|
Definition
in axonal migration: there are signals in both the axon and the target organ that specify where synapses are going to form. so must be a chemical match b/w axon and target
in retina there is ephrin receptor and in tectum there is ephrin ligand. very high levels of ligand inhibit axonal migration, so receptors from post-retina (high levels of receptor) migrate to tectum w/low levels of ephrin ligand |
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Term
| how do clusters of neurons like column of terni, lateral motor column, and medial motor column form? |
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Definition
| cell bodies of motor neurons projecting to a single muscle are clustered in a longitudinal column of the spinal cord via expression of specific cadherins in the neuronal surface. and clusters are grouped into longer columns. |
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Term
| motor neurons in the column of terni project to? |
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Definition
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Term
| motor neurons in the lateral motor column project to? |
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Definition
| dorsal muscles in the limb area |
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Term
| neurons in the medial motor column project to? |
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Definition
| ventral musculature in limb areas |
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Term
| what is the basis for the target specificity of columns like column of terni, lateral motor column and medial motor column? |
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Definition
| targets of motor neurons are specified before axons extend into periphery prob has to do with combination of TF, particularly of the Lim and Hox family, expressed in neurons. these factors prob encode for specific ephrin receptors that bind to ephrin ligands in the muscles (ephrin receptors on axons and ephrin ligands on target tissue, remember frog retina) |
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Term
| alzheimers is histologically defined by 2 pathologies |
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Definition
| amyloid plaques (extracellular deposits consisting mainly of aggregated b-amyloid peptide) and neurofibrillary tangles (intracellular deposits consisting of hyperphosophorylated tau protein - result in neuronal death |
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Term
| what is the substantia gelatinosa? |
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Definition
| in the anterior spino-thalamic pathway, pain fibers thought to use substance P as a NT synapse superficially in the dorsal horn in an area called substantia gelatinosa |
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Term
| the collaterals given off by the spino thalamic tract on its ascent into thalamus go to 3 places |
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Definition
| lateral reticular formation, deep layers of tectum, midbrain central gray |
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Term
| spino-thalamic tract terminates in 3 sets of thalamic nuclei. they are? |
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Definition
| VPL nucleus, intralaminar nuclei, part of the posterior nuclear group (Po) |
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Term
| brodman's areas that represent deep sensations? |
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Definition
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Term
| brodman's areas that represent cutaneous sensation |
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Definition
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