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Thomadaki Neuro II
NYCC Thomadaki 2nd half of midterm info from pontine reticulospinal tract
| Question | Answer |
|---|---|
| from the reticular formation in the pons to ventral horn cells bilaterally. Facilitation of ANTIGRAVITY muscles i.e., extensors of the lower limb (Name this ventromedial pathway) | Pontine Reticulospinal tract |
| Ventromedial pathways have to do with what kind of muscles? | proximal/core |
| __________ & __________reticulospinal tracts facilitate antigravity muscles like the lower limb extensors. | PONTINE & Medullary (the Prs. and Mrs. Kennedy) |
| __________reticulospinal tract is from the reticular formation to the pons to ventral horn cells bilaterally. | PONTINE |
| What ventromedial pathway involves antigravity extensor muscles and runs from reticular formation to pons to ventral horn cells bilaterally? | PONTINE reticulospinal tract |
| from the reticular formation in the medulla to ventral horn cells bilaterally. Inhibits antigravity muscles. | Medullary reticulospinal tract |
| from the reticular formation in the medulla to ventral horn cells bilaterally. | Medullary reticulospinal tract (the Mrs.) |
| what kind of muscles does the Mrs. (Medullary reticulospinal tract) control/facilitate? | proximal/core muscles/ANTIGRAVITY |
| The Prs. and Mrs. Kennedy facilitate the control of | ANTIGRAVITY muscles like extensors of lower limb |
| The ________________tract controls head and back muscles based on directional information and facilitates upper and lower limb extensors. | Vestibulospinal tract (vs.) |
| from where does the vestibulospinal (vs.) tract receive its information? | vestibular apparatus in the inner ear |
| Where is the vestibulospinal tract? (vs.) | from the vestibular nuclei to ventral horn cells bilaterally |
| function of vestibulospinal tract (vs.) | controls head and back muscles based on DIRECTIONAL information it receives from the vestibular apparatus in the inner ear, and facilitates UPPER and lower limb extensor muscles |
| what pathway is the vestibulospinal tract (vs.) a part of? | Ventromedial pathway for proximal muscle facilitation (and, in the case of vs., for directional control of head and back muscles via info from the vestibular apparatus of inner ear) |
| the ___________ tract runs from the superior colliculus (which receives retinal input), decussates in medulla then ends in ventral horn cells. | TECTOspinal tract (deTECTO!) |
| The tectospinal tract (from superior colliculus/retinal input to ventral horn cells) facilitates ? | orientation of the head and eyes to a stimulus (deTECTO!) |
| Which tract orients head and EYES to a stimulus? | TECTOspinal tract (deTECTO!) |
| Lesion of the brainstem ABOVE the vestibular nuclei eliminates both ? | corticospinal and rubriospinal (the lateral corticospinal pathways that control distal flexors) |
| Where is a lesion that knocks out both the corticospinal and rubriospinal pathways (the lateral pathways that control distal flexors)? | above the pons but below the red nuclei (at level of superior colliculus) so above the vestibular nuclei |
| What does a lesion below the red nucleus but above the pons and vestibular nuclei cause? | Decerebrate Rigidity by knocking out corticospinal and rubriospinal pathways (distal flexors) |
| Decerebrate Rigidity | knocks out lateral paths (corticospinal & rubriospinal) between R.nucleus and pons that control the distal flexors. Tonic EXTENSION seen during noxious stimuli, since reticulospinal influences tend to cancel each other out. |
| involuntary flexion or extension of the arms and legs, indicating severe brain injury. One set of muscles becomes incapacitated while the opposing set is not, and an external stimulus such as pain causes the working set of muscles to contract | abnormal posturing, like decerebrate rigidity |
| _________and decorticate posturing are strongly associated with poor outcome in a variety of conditions | Decerebrate (extension) |
| Why does the entire extensor set of muscles react in decerebrate rigidity? | Because the rubrospinal (distal primary upper extremity flexors) and corticospinal (distal flexors) are knocked out so the Vestibulospinal are only ones working above pons (vestibular nuclei) but below red nucleus. Full posterior extension. |
| Most common classic brain stroke presentation | Decortitate rigidity |
| Why is DeCEREBRATE rigidity typically seen only during noxious stimuli if corticospinal and rubriospinal tracts (distal flexors) are knocked out? | Because reticulospinal (Prs., Mrs., vs., and deTECTO!) influences on head, neck and back antigravity extensors seem to cancel each other out |
| Which is due to knock out between red nucleus and pons, but above vestibular nuclei level: decerebrate or decorticate rigidity? Why? | DeCEREBRATE because the corticospinal and rubriospinal between pons and r.nuclei and the reticulospinal antigravity systems cx each other out. Only one left? Vestibulospinal so full extension of upper and lower limbs! |
| _________ & ________ rigidity/posturing can indicate that brain herniation is occurring[7] or is about to occur | Decerebrate and decorticate rigidity/posturing |
| Brain herniation is an extremely dangerous condition in which parts of the brain are pushed past hard structures within the skull. In herniation syndrome, which is indicative of brain herniation, _________ occurs 1st then ________ if left untreated. | Decorticate 1st (extend legs but flex arms), Decerebrate 2nd (full tonic extension of body) |
| Why does decorticate rigidity/posturing occur? | lesion of cerebral hemispheres with intact brainstem that wipes corticospinal but leaves rubriospinal (arm flexors) intact. Vestibulospinal is also intact so extension of legs at same time. |
| Why doesn't the rubriospinal tract for distal primary flexors stop the legs from extending during decorticate rigidity, like it does to the arms? (decorticate is arm flexion, leg extension after injury) | the rubriospinal tract is still intact after corticospinal is wiped, but projects more to cervical area of spinal cord so loses countering influence against vestibulospinal as it goes down. Flexes arms upper but loses battle with V.spinal so legs extend. |
| rubriospinal versus vestibulospinal tracts | rubriospinal: distal upper limb flexors, vestibulospinal: head and back muscles + arm and leg extension. Rubrio is lateral path, Vestibulo is ventromedial. Decorticate rigidity-rubrio wins flexion of arms, vestibulo wins extension of legs |
| If you whack the corticospinal tract, what results? | paralysis |
| most common brain stroke/classic presentation of injury where brain is jerked past a bony projection in skull leaving intact brainstem | decorticate rigidity - wipes corticospinal distal legs and torso flexors but leaves rubriospinal distal arm flexors. Vestibulospinal of proximal extensors wins legs due to mainly cervical projections of red (rubrio) nucleus. |
| one motor neuron and all the muscle fibers it innervates | MOTOR unit |
| what is a motor unit? | One motor neuron and all the muscle fibers it innervates |
| what is a motor neuron pool? | all the motor neurons needed to innervate one muscle |
| all the motor neurons needed to innervate one muscle is called a | motor neuron POOL! a resource pooling of neurons that are required to operate one muscle |
| the neurons of a bunch of motor units make up a | motor neuron pool |
| which is worse, decorticate or decerebrate rigidity? | decerebrate - this means the red nucleus (hence rubriospinal tract) is gone, too, indicating a lesion lower in the brainstem |
| Wikipedia contradicts or fills in the missing peices on the ventrolateral pathway versus lateral pathways. Please see "abnormal posturing" for a more comprehensive, less contradictory explanation than the lecture notes. | opisthotonos, which arches head and back, is not mentioned in notes. |
| The rubrospinal tract and medullary reticulospinal tract biased flexion outweighs the medial and lateral vestibulospinal and pontine reticulospinal tract biased extension in the upper extremities (Wikipedia: abnormal posturing) | this is another blank in the lecture notes where medullary reticulospinal are said to inhibit antigravity muscles but no mention is made of working with flexors and rubriospinal to counter during decorticate rigidity. |
| What kind of neurons of the brainstem and spinal cord innervate skeletal muscle? | LMN lower motor neurons |
| What kind of nuclei do cranial nerves and their processe use? | LMN lower motor neurons |
| LMN's of skeletal muscle originate as | ventral horn cells and their processes |
| innervate extrafusal skeletal muscle fibers | Alpha (alphas are outgoing types that prefer the extrafusal skeletal muscle freedom to their gamma counterparts that prefer intrafusal/encapsulated spindle lifestyles) |
| innervate intrafusal/intracapsular muscles spindles | gamma motor neurons (very sensitive types) |
| alpha motor neurons versus gamma motor neurons | Alphas are extrafusal skeletal muscle while gammas are intrafusal/encapsulated muscle spindles |
| De__________ rigidity/posturing indicates brain stem damage, specifically damage below the level of the red nucleus (e.g. mid-collicular lesion). It is exhibited by people with lesions or compression in the midbrain and lesions in the cerebellum | Decerebrate (you are now separated from you cerebral hemispheres and exhibit full body extension.) |
| Progression from decorticate posturing to ______________ posturing may indicate uncal (transtentorial) or tonsilar brain herniation. | decerebrate |
| Activation of _______ motor neurons is thought to be important in decerebrate rigidity due to studies in animals showing that dorsal root transection eliminates decerebrate rigidity | gamma (dorsal root being sensory so gamma muscle spindle intrafusal/encapsulars are sensory) |
| Normally people displaying _______________or _______________are in a coma and have poor prognoses, with risks for cardiac arrythmia or arrest and respiratory failure | decorticate or decerebrate rigidity/posturing |
| symptoms of a LMN | paresis/paralysis/plegia, atrophy, fasiculations, hypo(a)tonia and hypo(a)reflexia (flaccidity) |
| LMN means | flaccid |
| fasiculations are symptoms of ? What are they? | LMN (flaccid)lesions. Visible muscle twitching resulting from involuntary synchronous contraction of all the muscle fibers in a motor unit. (hitting all the keys on keyboard at once) |
| fasiculations | LMN visible muscle twitching due to involuntary synch contraction of all muscle fibers in a motor unit at once |
| a characteristic of slowly progressive diseases of the motor unit | fasiculations |
| fasiculations - involuntary contraction of an entire motor unit's fibers - means slowly progressive >>> | disease of motor unit |
| fibrillations are the spontaneous activity of _________________, ONLY detected with electromyelography | spontaneous activity of one muscle fiber |
| what do fibrillations indicate? | a sign of progressed muscle denervation or myophathy |
| which can be seen with the naked eye: fibrillations or fasiculations | fasiculations (spontaneous firing of all muscle fibers of one motor unit a single muscle fiber firing as in fibrillation is too small to see without EMG) |
| which one means the motor unit is diseased, fibrillation or fasiculation | fasiculation |
| which one means progressed muscle denervation or myopathy: fasiculation or fibrillation | fibrillation (one fibril of a muscle) |
| the __________________ is a length sensor | muscle spindle |
| What 3 things does a muscle spindle detect? | length of the muscle, change in length of the muscle, speed in change of length |
| each muscle spindle contains an average of 10 single cells (fibers) called | INTRAFUSAL (encapsulated) fibers |
| the rest of the muscle fibers - those that actually contract - are called ______________ fibers. | extrafusal |
| Each muscle as many spindles. The small abductor pollicis has 80 vs. the lastissimus dorsi with 350, but the 80 of the aBductor pollicis are in considerably closer proximity or ___________- | density. Small muscles have muscle spindles in greater density, not number |
| the contractile portion of a muscle spindle is where? | at the ends |
| the non-contractile sensory portion of a muscle spindle is in | the middle of the spindle |
| Around the non-contractile SENSORY portion of a muscle spindle is the annulospiral (circumferential) ending of what? | 1a spindle afferent wrapped around it |
| The 1a spindle afferent wraps around the non-contractile sensitive middle of a muscle spindle. What is glued to the contractile ends (reactive/motor) ends of a muscle spindle? | gamma motor fiber |
| The contractile portions of the spindle cell are at its ends and receive their motor supply from | gamma motor neurons |
| Discharge of gamma motor fiber will cause the contractile end of the spindle to contract, which will stretch the _________________ with its annulospiral ending. | central sensory portion (1a spindle afferent) |
| Like twisting the ends of a sponge (the contractile spindle ends attached to gamma motor fibers), the middle of the sponge bulges, stretching the | central sensory portion of 1a spindle afferent |
| what determines the sensitivity of the spindle by maintaining its sensory portion at the critical threshold? | gamma motor neuron |
| The muscle spindle not only fires off when the muscle is lengthened, but also discharges at a steady low frequency when the muscle is "at rest," or ? | not changing in its length |
| where is the unipolar cell body of 1a spindle afferent? | in the dorsal root ganglion of the sensory/dorsal root |
| where is the gamma motor neuron cell body | in the ventral horn of the spinal cord gray matter in the vicinity of alpha motor neurons. Its axon leaves the spnal cord in the ventral root and travels to the target muscle in the same nerve as Alpha motor axons. |
| Appreciate the fact that the gamma motor neuron can neither lengthen or shorten the spindle; the length of the spindles is determined by the | length of the muscle itself. |
| The gamma motor neuron "tightens up" the _________ ___________part of the spindle. | central sensory. |
| The muscle spindle is not subjected to _______ within the muscle. | tension |
| name 3 places (terminal branches) of 1a spindle afferents | 1-dorsal columns (f.cuneatus & f.gracilis), 2-an ending upon an inhibitory neuron that inhibits the Alpha motor neuron to the muscle, or 3-a synapse directly upon the alpha motor neuron to the same muscle. |
| when the biceps is extended, the muscle spindle is | stretched |
| when the biceps is contracted, the muscle spindle is | shortened |
| Name the 3 components of a 2-neuron monosynaptic reflex | 1a spindle afferent fiber, the Alpha motor neuron, and the synapse between the two |
| the 1a spindle fiber afferent, the Alpha motor neuron, and the synapse between the two constitutes a | 2-neuron monosynaptic reflex |
| The 2-neuron monosynaptic reflex (1a spindle afferent, Alpha motor neuron, and synapse between the two) are the basis for the _________ or _______ reflex. | myostatic or stretch reflex |
| what is the basis for the myostatic/stretch reflex? | the 2-neuron monosynaptic reflex involving 1a spindle afferent, an Alpha motor neuron, and the synapse between the two |
| example of the myostatic/stretch reflex | tapping the patellar tendon and the resultant knee jerk |
| when the biceps contracts, its spindle shortens. This occurs when its ________motor neuron (agonists) discharge. | Alpha |
| In normal movement the contraction of any single muscle probably requires tens or hundreds of motor neurons to discharge, each causing the contraction of al the muscle fibers that it innervates, that is, its ___________. | motor unit |
| When a muscle contracts, not only do its Alpha motor neurons discharge but the ___________motor neurons discharge simultaneously | gamma and Alpha both discharge simultaneously |
| The coactivation of gamma and Alpha motor neurons ensures a continuous sensitivity for the spindle so it does not become desensitized or unloaded whenever it is __________. | shortened (when the muscle contracts) |
| Coactivation of gamma and Alpha not only keeps the spindle sensitive to contraction but increases the rate of firing for the | Alpha motor neuron and hence, the force of contraction |
| What happens in coactivation? | the gamma and Alpha fire at once, keeping the gamma sensitive even if it is not involved in inhibition but also increasing the speed, ergo force of muscle contraction, for the Alpha motor neuron. |
| A muscle ______ is a specialized skeletal muscle fiber inside a fibrous capsule (intrafusal) situated parallel with the extrafusal muscle fibers. | spindle |
| spindles are intra or extra fusal? | intrafusal/encapsulated |
| components of a muscle spindle | intrafusal spindle fiber, 1a spindle afferent, gamma motor neuron |
| 1a spindle afferents are ________ for the spindle | sensory |
| gamma motor axons are _______ for the spindle | motor |
| When there is a change in muscle length, the 1a spindle afferents send info to the CNS about muscle stretch (to dorsal columns, inhibitory neuron, or straight on to Alpha motor neuron to that muscle) -Contraction causes the intrafusal fibers to | become slack. Gamma motor neurons cause them to reset or tighten back up to maintain sensitivity. |
| Why do gamma motor neurons cause spindle fibers to tighten up after a contraction? | to maintain sensitivity (sproing!) |
| What are the two kinds of spindle afferents and what are their descriptive names? | 1a and 2 (Ia and II), known as 1a annulospiral spindle afferents and 2 flower spray spindle afferents |
| Ia annulospirals | 1a's are spindle afferents non-contractile sensory portion of 2-neuron monosynaptic reflex that wraps around (annulo spirals) the middle of a spindle fiber. |
| II flower sprays | like 1a's, are the non-contractile sensory afferents of spindle fibers that detect stretch |
| Nuclear chain fibers | a type of intrafusal spindle fiber, thin, nuclei arranged single file instead of bunched in middle, afferents include both 1a and II (annulospirals and flower sprays) |
| Nuclear bag fibers | fat in der middle! thicker, nuclei grouped centrally = has two subtypes of dynamic and static |
| nuclear bag fibers (fat in der middle) have two subtypes: | dynamic (1a spindle afferents only - fast response) and STATIC (slow adapters, includes 1a and II both) |
| monosynaptic connection between the central axon of the 1a spindle afferent and the alpha motor neuron, causing a muscle contraction in response to stretch | Stretch/myostatic reflex |
| The 1a annulospiral spindle afferents (of both nuclear chain and dynamic nuclear bag fibers) not only synapse on the alpha motor neuron of the muscle to be contracted (agonist) but also synapse on | an INHIBITORY interneuron connected to the alpha motor neuron of the antagonist muscle, too, so that both don't contract at the same time (what's that disease called?) |
| The reflex that keeps both antagonist and agonist muscles from simultaneously contracting + mechanism: | 1a Inhibitory reflex: 1a spindle afferents synapse on Alpha motor neuron of agonist/target muscle to be contracted and also on an INHIBITORY interneuron connected to the antagonist/opposite muscle to get it to relax. |
| What is also discharging along with the Alpha motor neurons after they've been synapsed by 1a spindle afferents and inhibitory neurons? | gamma motor neurons, in order to keep the spindle sensitized (sproingy!) |
| stretch reflex is the monosynaptic connection between the central axon of the ____________ and the Alpha motor neuron, causing muscle contraction in response to ________. | 1a spindle afferent fiber, stretch |
| what kind of cells are involved in Recurrent Inhibition? | Renshaw cells (interneurons) |
| To avoid over excitation of the agonist motor neuron POOL (the muscle neurons for the specific muscle you are trying to contract), the agonist _______motor neuron synapses on an inhibitory Renshaw cell. | Alpha motor neuron (or the descending tracts exciting that Alpha) |
| Remember the 1a inhibitory reflex? | the central 1a afferent axon (1aaa)coming from the spindle fiber synapses on a 1a inhibitory interneuron as well as the Alpha to the agonist. The interneuron is cx to the antagonist muscle and inhibits the antagonist from co-contracting with the agonist. |
| What does the Renshaw cell do in recurrent inhibition? | inhibits 1a interneorons from inhibiting the antagonistic muscle, which also inhibits the agonist being contracted. |
| What does inhibition of the 1a interneuron inhibitor of the antagonist by a Renshaw cell produce? | Recurrent inhibition = negative feedback for controlling excitability of all the muscles around a joing |
| The Renshaw cell could also be called | The Governor or The Nanny (makes sure all the children/lobbyists get attention so no one party gets too excited and loses control) |
| ___________feedback of recurrent inhibition/Renshaw/Nanny cell allows for control of the excitability of all the muscles around a joint. | negative |
| encapsulated sensory receptors located at the intersection of muscle and tendon, in series with extrafusal muscle fibers. | GOLGI TENDON ORGANS |
| Do tendons like to stretch? What does? | no. not at all. Muscles! |
| where would a stretch receptor be found, in the muscle which likes to stretch or the tendon which does not? | muscle! Nature doesn't waste energy on worry. |
| Tendon is synonymous with Tension. What would the tendon have in it at the musculotendinous junction? | a Tension receptor = GOLGI TENDON ORGAN |
| Golgi tendon organ is a Golgi tension detector. What kind of fibers provide sensory innervation to Golgi's (analgous to sensory afferents for muscle spindles)? | 1b proprioreceptors |
| You can "b" certain it's a Golgi tension pro! | 1b proprioreceptors for Golgi tendon organs at musculo-tendinous jcn for tension detection |
| You can "b" certain it's a Golgi tension pro! | 1b propriorecptors for tendon tension |
| who controls 1a interneuron inhibition during inhibitory reflex of antagonist and what is it called? | Renshaw for Governer - Recurrent inhibition policy |
| Renshaw for Governer -Recurrent Inhibiton policy | to avoid overexcitation of motor pool to agonist, Renshaw inhibits 1a interneuron inhibitor to antagonist, and inhibits the agonist. This elicits control of excitability of muscles around a joint. |
| 1b proprioreceptors | found in Golgi tendon organs, detect tension, are part of the 1b reflex |
| 1b reflex (3 parties) | Central axons of the 1b proprioreceptor fibers from GTO, cutaneous receptors, joint receptors all synapse on 1b inhibitory neuron |
| The axon of the alpha-motoneuron then exits the spinal cord through the ventral root and innervates the extrafusal fibers of the muscle from which the group Ia afferent fiber originated, called the ______________muscle. | homonymous |
| The contraction in turn causes the spindle to be unloaded or shortened passively, its equatorial region to relax, the group ___ afferent fiber to turn off, and the muscle to relax. This is the tendon jerk reflex. | Ia (1a) |
| Most skeletal muscles exhibit a tendon tap reflex, but the reflex is strongest in the ___________ or physiological extensor muscles | antigravity |
| clinically note that reflexes involve only one or two segments of the spinal cord. In The spinal cord can be cut above and below these segments, and the reflexes will still occur. Testing such reflexes? | cannot be used to determine a brain or spinal cord injury |
| It is a general principle that anything that has an excitatory (or inhibitory) influence on an alpha-motoneuron also inhibits (or excites) the alpha-motoneurons of its antagonist muscle. This is the principle of reciprocal innervation | Thus, for example, excitation of the hamstring alpha-motoneurons by group Ia afferent fibers is accompanied by inhibition of quadriceps alpha-motoneurons. Reciprocal inhibition is a specific example of the more general principle of reciprocal innervation |
| If you have ever touched a hot object or stepped on a sharp object and withdrawn your hand or foot, you have experienced a _________reflex, a nocifensive reflex, or a withdrawal reflex, all terms describing the same event | FLEXION reflex (hot stove!) |
| hot stove reflex! | FLEXION REFLEX |
| The protective result of FLEXION reflex is obvious; it quickly removes the part of the body from the vicinity of the offending object by contracting the appropriate muscles, usually flexors, and relaxing ________ muscles (again, reciprocal innervation). | extensor |
| what carries the reflex info of stepping on a tack to the spinal cord? | Flexor reflex afferent fiber (similar to 1a spindle afferent) |
| When flexor reflex fiber is stimulated by stepping on a tack, what happens at the cord? | enters via dorsal root and synapses on an inhibitory interneuron to the antagonist extensor and directly on the agonist flexor so you will reflexively jump off the tack! |
| What are the flexor reflex afferent fibers made of that let you know you've stepped on a tack? | The afferent limb (the part going to the spinal cord) of this reflex consists of nociceptors with A or C fibers and fibers of groups II, III, and IV of muscle. These are sometimes referred to collectively as the flexor reflex afferent fibers |
| http://www.unmc.edu/physiology/Mann/mann15.htmlreflexes webpage | see that page for good diagrams |
| They enter the spinal cord and synapse on interneurons, whose axons distribute to other interneurons that affect alpha-motoneurons within the same and | and in different levels of spinal cord - remember pain travels 2 doors up |
| If protection of the limb requires it to be elevated, then the rest of the body is imperiled by removal of the support the limb normally provided, unless some compensation is made | Crossed-EXtension reflex |
| The reflex contraction of flexor muscles on one side of the body is always accompanied by contraction of the extensor muscles of the contralateral limb | Crossed-EXtension reflex |
| This gives increased antigravity support on the contralateral side to hold the body upright during flexin reflex and is called the _____________reflex | Crossed-EXtension reflex (contraction of extensor muscles of the contralateral limb to provide antigravity support while you hop around like an ass after stepping on a tack) |
| The flexor reflex afferent fibers also synapse on interneurons that decussate (cross the midline) and terminate on contralateral extensor alpha-motor neurons | Crossed-Extensor reflex - the flexor reflex afferents also decussate to the other side of the cord so the muscles attached to the opposite ventral horn alpha motor neurons are told to extend! Keeps you upright on one foot after stepping on a tack. |
| This pathway is polysynaptic and purely excitatory. In addition, there is the usual reciprocal inhibitory effect on the contralateral flexor alpha-motoneurons. | Crossed-EXtension reflex, meaning the contralateral flexors won't counteract the full extension of the un-hurt (no-tack) side in order to keep you standing upright |
| Activity in the group Ib afferent fibers, associated with _______________, inhibits the homonymous alpha-motoneurons | Golgi Tendon organs |
| the stretch reflex is a ___________connection, while the flexion and crossed-EXtension reflexes are ___________. | monosynaptic, polysynaptic |
| Renshaw Cell (governor) | governor - withdraws inhibition of 1a (muscle spindle afferent) INTERNEURON so the antagonist is excited, but also excites the agonist. Neg feedback for controlling excitability of joint muscles. |
| where are the deep sensibilty tracts? | dorsal columns/medial lemniscus pathway |
| F. gracilis (T6down) and F.cuneatus (T6up) carry | VDPP - vibration, discrimination, pressure, proprioreception (F.Cuneatus only) ipsilaterally and end in the medulla |
| where do the F.gracilis and F.cuneatus fibers end/ | in the medulla at the internal arcuate fibers = becomes the MEDIAL LEMNISCUS |
| where does the Medial Lemniscus system of VDPP from dorsal columns end? | thalamus VPL (ventral posterior lateral thalamic nucleus) |
| thalamus VPL | end of medial lemniscus/VDPP from deep sense |
| from the thalamus VPL, where do the VDPP sensory fibers go? | through the INTERNAL capusule to the somatosensory cortex (Broadmann's 3.1.2) |
| what is the somatatopic representation of the medial lemniscus-VDPP-VPL thalamus to somatosensory cortex? | homunculus with knees longitudinal fissure bend then legs, trunk, arms, face as you go coronally lateral |
| how to examine the dorsal column/medial lemniscus pathway | vibration tuning fork on dermatomes, position sense of mainly upper extremities, Romberg's test |
| proprioreception for lower extremities runs in the | spinocerebellar tract |
| proprioreception for upper extremities runs in the | cuneocerebellar tract, which is an offshoot of the f.cuneatus |
| Romberg's is a test for | deep sense/medial lemniscus |
| trace medial lemniscus path | dorsal columns - internal arcuates - medial lemniscus - VPL - internal capusle - somatosensory cortex primary (Broadmann's 3.1.2) |
| The ___________ system is made of the spinothalamic, spinoreticular, and the spinomesencephalic tracts all involved with pain and temperature perception. | Antero-lateral system is P&T |
| where does P&T from antero-lateral system go? | DLF (tract of Lissauer) and end in dorsal horn at substantia gelatinosa and nucleus proprius. Synapses across VWC and ascends in spinothalamic tract to the VPLthalamus. |
| From VPLthalamus, where do spinothalamic tract fibers go? | up through internal capsule to end in somatosensory cortex (Broadmann's 3.1.2) |
| somatotropic representation of both anterolateral system (spinothalamicreticularmesencephalon) and of the medial lemniscus/deep sense | sensory homunculus |
| examination of anterolateral Pain&Temperature system (spinoreticular, spinothalamic, spinomesencephalic) | pin-prick (wheel) over dermatomes |
| higher control of autonomic function, homeostasis, reproduction, emotion, motivated behavior, learning (feeding, fighting, f...) | limbic system |
| fornix | the main output of the hippocampus (paw, dentate gyrus, Ammon's horn/h-proper) |
| components of the limbic system (2) | limbic lobe and limbic system |
| limbic lobe was named by | Paul Broca (Broca's area) |
| septal area, cingulate gyrus, parahippocampal gyrus, hippocampus, amygdala, uncus | limbic lobe |
| aunt amygdala and uncle uncus are part of the | limbic lobe |
| limbic system includes the | limbic lobe and all its cortical and subcortical connections (Papez circuit) |
| Papez circuit | 1937 James Wenceslas Papez (1883-1958) proposed a mechanism of neural circuitry to explain how intellectioal fcn is connected to deicephalic nuclei responsible for feeling and emotion |
| Papez circuit | Anterior thalamic nuclei-thalamocortical fibers-cingulate gyrus-cingulum-entorhinal cortex-hippocampal formation(paw&horn)-fornix-mammillary body (Hypothalamus)-mammillothalamic tract-anterior thalamic nuclei again |
| Thomadaki Papez circuit structures: | limbic lobe and hypothalamus, thalamus, brainstem reticular formation, epithalamus, olfactory cortex, prefrontal cortex |
| Hippocampal formation | part of PARAHIPPOCAMPAL GYRUS, contralateral hippocampus via the hippocampal commissure, amygdala, thalamus, locus coeruleus, raphe nuclei, ventral tegmental area |
| function of HIPPOcampus | map of spatial memory - LEARNING AND MEMORY especially short term into long term explicit |
| lesion of HIPPOcampus | explicit memory and spatial orientation |
| the ability to learn, retain and improve skills is a function of __________ memory | IMPlicit |
| explicit is also called ________memory | declarative, like the kind you need for this test but that it's too late to improve |
| which lobe is responsible for declarative/explicit memory of spatial events and factual learning? (which lobe did you whack in the car accident on the driver's side window)? | middle temporal lobe |
| Implicit or non-declarative memory has to do with | priming, procedural skills, emotional responses to learning associations, musculoskeletal resp to associative learning |
| priming (I.)mplicit brain area | neocortex |
| procedural skills and habits I. | striatum |
| emotional reactionism I. | amygdala |
| somatic training I. | cerebellum |
| 4 types of amnesia | retro, antero, global, modality specific |
| what kind of information converges on the amygdala | autonomic, sensory, auditory, visual |
| the amygdala travels along the ___________of the thalamus | stria terminalis to the septal nuclei, hypothalamus, brainstem and cortex |
| function of amygdala is affective perception of | sensory stimuli |
| fear and hate center | amygdala |
| bad smells go with bad feelings | amygdala |
| lesion to amygdala | no fear |
| bilateral experimental lesion of monkey temporal lobes including amygdala and hippocampal formation (fear, hate, spatial memory and explicit LTP) | Kluver Bucy Syndrome |
| Kluver Bucy, temporal deucy, makes a monkey blind and loosey. No fear, no hate, or nasty memories to boot; it eats its thumb then throws it up, but doesn't give a shoot. | Kluver Bucy Syndrome -bilateral temporal lobe lesion to hippocampus and amygdala |
| what is syndrome caused by thiamine def. seen sometimes in severe alcoholism with halmark confabulation | Korsakoff's |
| what kind of amnesia is Korsakoffs | anterograde then retro |
| uncinate fits | temporal lobe epilepsy olfactory hallucinations |
| deja vu | visual hallucinations |
| gustatory, auditory, visual, uncinate (smell) hallucination, and lip smacking, motor acts, amnesia and aggression are all possible _________ _______lesion | temporal lobe |
| schizo is abnormal temporal lobe what? | differentiation |
| Alzheimer's senile plaques contain an __________protein in the | amyloid, temporal and parietal cortices |
| amygdala, septal area, parahippocampus and hippocampus are what lobe | temporal |
| what is the transient rage, oh wait, I'm thirsty! area | septal area |
| emotional behavior, stimulation results in transient rage and incrased water consumption, and a reward rx | septal area |
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