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189 Cards in this Set

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  • Back
What does the facial nerve supply?
The facial nerve, CN VII, carries parasympathetic information for salivary (except parotid) and lacrimal glands, anterior 2/3 taste, muscles for facial expression, eyelid, stapedius, stylohyoid, and posterior belly of the digastric.
What does it mean when your tongue deviates to a side?
Deviation of the tongue occurs towards the side of CN XII damage
What does it indicate when your uvula deviates to one side?
deviation of the uvula occurs with CN X deficiency
What does the paramedian branch of anterior spinal artery supply?
The paramedian arterial (ASA) supply covers the regions occupied by the medial lemniscus, as well as eye muscle nuclei, the medial longitudinal fasciculus MLF and the corticospinal tract.
What is Wallenberg syndrome?
a lateral medullary lesion (PICA infarct) that is characterized by dizziness, hoarseness, loss of pain/ temp in face, contralateral loss of body pain/ temp, and ipsilateral papillary constriction.
Ambiguus Nucleus
9, 10

motor to larynx, pharynx, and palate
Dorsal nucleus of Vagus

PS for vagus
Salivatory nucleus

PS for salivation
Solitary nucleus

Cuadal-“cardio-respiratory center” that receives most of the visceral afferents from the thoracic and abdominal viscera
Spinal nucleus of 5

Sensation from face, mouth, and pharynx (esp. pain)

muscles of facial expression, eyelid
Motor nucleus of 5

muscles of mastication
Mesencephalic nucleus of 5

proprioception from muscles of mastication
principal sensory nucleus of 5

discriminative sensation from face
Where does the olfactory bulb project to?
olfactory bulb projects directly to the piriform cortex, the anterior olfactory nucleus, and the amygdala, which is why smells are thought to elicit emotional responses and memories
What is the piriform cortex?
portion of the paleocortex which the olfactory bulb projects to
What are some of the deficits you would see with a stroke of the left IC that impaired corticobulbar innvation to the brainstem?
contralateral hypoglossal
contralateral facial weakness below the eyelid
ipsilateral weakness in shoulder shrugging
Which receptors are rapidly adapting?

Which are slow?
RA-Meissner's(closer to surface;stroking and fluttering)
-Pacinian (deep;vibration)

Which are larger diameter?
A or C
I or IV
A (Sensory)
I (Muscle)
What are the factors and cell types involved in tissue inflammation?
The tissue inflammation factors we discussed include histamine, prostaglandins, 5-HT (serotonergic, not GABA-ergic), cytokines, IL-1, and TNF. The cell types responsible for this “mediator soup” include mast cells, fibroblasts, macrophages, and sympathetic nerve varicosities
What is diffuse noxious inhibitory controls(DNIC)?
DNIC is defined as a physiologically-inducible phenomenon whereby widespread depression of the multi-convergent wide dynamic range in the spinal cord is observed following pain stimulus anywhere else in the body. This process requires preservation of the nucleus reticularis dorsalis.
What is secondary hyperalgesia?
Secondary hyperalgesia occurs when after a localized trauma, tenderness (mechanical, but not thermal) spreads to a distant area where no inflammation exists
IF you decrease the size of a receptive field, what happens to the cortical area?
Type S motor units(Type I)
low fatiguability
long afterhyperpolarization
oxidative metaboilism
slow AP conduction
What is the clasp-knife reflex?
The clasp-knife reflex is not mediated by either the golgi tendon organ or muscle spindles, as may have been previously thought. The clasped knife reflex is also called the inverse myostatic or autogenic reflex. It is activated when muscles contract to a certain threshold and need to be lengthened. The increased resistance required is akin to opening a clasped knife.
Golgi tendon organs
Golgi tendon organs are located at the junction between muscle fibers and tendon. Each organ is innervated by a single group Ib axon and are most sensitive to changes in muscle tension.
Muscle spindles
A muscle spindle is most sensitive to changes in the length of the muscle and is found in the fleshy portion of the muscle. The spindle consists of intrafusal fibers that are innervated by gamma neurons, as opposed to the alpha innervation of the extrafusal fibers.
What hair cells sense vertical, horizontal, and rotational movement?
rotational-semicircular canals
List the three systems important for spatial positioning in order of slowest to fastest.
An infarct of the MCA would result in what?
The MCA has two divisions when it comes to the lateral fissure, the superior and inferior arteries. Superior division supplies the pre and post central gyri. Occlusion of the superior division causes hemiparesis and hemisensory loss of the face and arm more than the leg. It also affects Broca’s speech area. People with a loss of Broca can understand you perfectly, but they cannot express themselves fluently. Inferior division supplies the lateral temporal lobe. Deficits here will affect Wernicke’s area, and patient’s will not be able to understand words and will speak fluently, but it will be nonsense. The optic radiations cross through the parietal lobe, and inferior division infarct will cause contralateral hemianopia. No hemiparesis will be present. Infarcts of the MCA could affect both divisions. Symptoms would include hemianopia, hemiplegia, hemisensory, global aphasia (if a left-sided infarct), and neglect (if right-sided)
In what ways does the primary motor cortex contribute to voluntary movement?
specifies direction, force, participating muscles. Also alters the muscle activity depending on motor task
What are some movement deficits in cerebellar disorders?
dysmetria, delay in initiation, and asynergia
The spinocerebellum division is made up of the vermis and regions that are just lateral to the vermis. It is called the spinocerebellum because it is the only portion of the cerebellum that receives sensory afferents from the spinal cord (it also receives afferents from the brainstem).
The spinocerebellum also receives visual and auditory inputs through the vermal region.
A Beta fibers
These are normally responsible for touch sensations. In pain sensitization they expand into laminae I and II, so that touch can induce pain.
Abnormal extensor posturing
Consequence of lesions below the 7th nerve nuclei.
Abnormal flexor posturing
Consequence of lesions above the level of the 7th nerve nuclei.
A-gamma fibers
Medium diametere lightly myelinated pain fibers. Responsible for the encoding of the acute pain. Involved in cutaneous mechanical, heat, and cold pain; Muscle group III mechanical and chemical pain; and joint pain.
Pain due to non-noxious stimuli (after a burn, simply touching it induces severe pain).
No sensitivity to pain, but sensitivity to non-noxious stimuli remains.
Loss of sense of smell. Can be difficult to distinguish from ageusia. The trigeminal neurons may know that there is an odorant, but there is no sense of olfaction. Can be the result of damage to neurons in the cribiform plate, alzheimer's, glioma around
Anterior cingulate cortex
Implicated in behavioral drive and volition. Active in virtually all studies of pain. Thought to be involved in homeostatic demands motivation of behavior.
Anterolateral (spinothalamic system)
Axons of dorsal horn neurons located in laminae I and IV, axons ascend a few segments on same side, then cross midline near the central canal, after crossing these axons ascend in the anterolateral white matter.
Area 1
Maps input from another set of rapidly adapting receptors. Senses tecture like area 3b, but not as good for patterns. Object size.
Area 2
Area of somatosensory cortex involved in higher order processing recieves input from deeper tissues, joint receptors, and cutaneous information associated with complex touch. Senses size and shape of objects.
Area 3a
Cortical area that mainly maps input from muscle stretch receptors.
Area 3b
Brodman area that mainly processes information from the skin and recieves cuteaneuous receptor input. Each column alternates between slowly (merkel) and rapidly (meissner's corpuscle) adapting cutaneuous information. This area is better at reproducing pa
Bell's Palsy
Damage to the facial nerve, or facial nerve nucleus results in paralysis of the ipsilateral upper and lower regions of the face.
Braille processing
This is best done by the slow adapting neurons of area 3b.
Brown Sequard syndrome
Results in a hemisection of the spinal cord producing a loss of fine touch on one side of the body distal and ipsilateral to the lesion while loss of pain and temperature occurs on the other side of the body.
C fibers
Small diameter unmyelinated pain fibers responsible for the encoding of second, prolonged, dull pain. Involved in cutaneous mechanical, cold, and polymodal pain; muscle group IV mechanical and chemical pain; joint pain, and visceral polymodal pain.
While integrins are important in mediating cell-matrix affinity at the neuromuscular junction, these cell adhesion molecules are important in the CNS.
Carpal Tunnel Syndrome
Associated with the median nerve stopping at the wrist.
Charcot Marie Tooth Disease
Generalized neuropathy characterized by high arched feet and hammer toes. Most common manifestation of the same gene invovled with HNPP.
corneal reflex
The rostral aspect of the spinal trigeminal nucleus is responsible for this reflex. In the case of damage to the caudal spinal trigeminal nucleus, this reflex is spared.
Cranial nerve six
Controls the ipsilateral lateral rectus (abduction), and the contralateral CN3 medial rectus neurons via the medial longitudinal fasciculus.
CRPS I/Reflex Sympathetic Dystrophy
Pain and sensory abnormalities, abnormal blood flow, decreased or increased sweating, motor system abnormalities, and changes in structure of both superficial and deep tissues. Mechanism involves alpha2 adrenoreceptors in the afferent membrane.
CRPS II/ Causalgia
A syndrome of sustained burning pain, allodynia, and hyperpathia after traumatic nerve lesions, often combined with vasomotor and sudomotor dysfunction, and trophic changes.
cytochalastin B
An inhibitor of actin polymerization. In the presence of this compound axons fail to grow.
DNIC (Diffuse Noxious Inhibitory Controls)
Pain control circuit that releases serotonin in the spinal cord. Explains the wide depression of wide dynamic array neurons. Requires the nucleus reticularis dorsalis.
Dorsal column/Medial leminiscus VPL neurons
Respond to specific modalities, have small receptive fields, have somatotropic organization, and exhibit activity that is proportional to sensory activity. Mediates complex discrimination tasks, and detects limb movement and joint position.
Dorsal horn mode 1
The control state, physiological sensitivity, low intensity->innocuous sensation, high intensity->pain.
Dorsal horn mode 2
Still in the normal range, this is the suppressed state. Low intensity and high intensity input both lead to innocuous sensation.
Dorsal horn mode 3
Sensitized state, still in the normal range. Postinjury hypersensitiviy, inflamatory pain, peripheral neuropathic pain. Low intensity -> pain, high intensity -> hyperalgesia.
Dorsal horn mode 4
Reorganized state, Peripheral neuropathic pain, central neurpathic pain, low intensity -> pain.
Dorsal nucleus of the vagus
Provides parasympathetic for the vagus nerve.
Dorsal posterior insular cortex
This area of the brain is active when heat is applied to the hand, in chronic pain conditions, itch, exercise, visceral sensation, and manipulations of blood pressure, thirst, hunger, hypercapnia and sensual touch. Primary interoceptive image of homeostat
Abnormal sensation; unpleasant painful or otherwise.
Ongoing discharge and stimulus-evoked activity arising at ectopic midnerve sites. It may develop in both low-threshold A-beta fibers and in high threshold A gamma and c fibers. In nociception it may induce pain directly and CNS sensitization. Na+ channe
Edinger-Westphal nucleus
Associated with cranial nerve 3. Pupil size, accommodation, eyelid.
Facial nerve
Has bilateral and contralateral components. The bilateral components innervate the face above the eyes and synapse on an interneuron, while the contralateral components cross somewhere in the rostral pons and innervate the lower face.
Facial nucleus
Associated with cranial nerve 7. Muscles of facial expression.
As axons grow, they can grow along the processes of another cell. This leads to nerve formation in the PNS and tract formation in the CNS.
Chronic pain and stiffness in multiple areas of the musculoskeletal system often accompanied by increased tenderness at specific sites called tender points. Like CRPS, sympathetic overactivity may contribute. Once thought to be psychogenic.
geniculate nucleus
Nucleus that can be important in ageusia because CN 7 is involved in taste. Ear infections can result in this problem.
guidepost cells
Not all signals in axon growth are attractive in nature. Some are repulsive.
Horner's syndrome
Ptosis, pupulary constriction (miosis), loss of sweating on the same side of face and neck, enophthalmos (crecession of the eyeball into the orbit), and redness of the conjunctiva due to dilation of the blood vessels caused by damage to autonomic innervat
Increased pain sensitivity (heat stimulus on a burn area is much more intense after experiencing a burn). Involves CNS and PNS sensitization, while the initial pain is due to nociceptor activity. C-nociceptors in the inflamed tissue have their threshold
A pain syndrome with increased reaction to a stimulus, especially a repetative one, and decreased threshold.
Increased sensitivity to noxious or non noxious stimuli.
Hypoglossal nerve
Is considered contralateral. Involved in control of the genioglossus muscle.
Involved in sympathetic and parasympathetic control, it has fibers projecting down through the central core of the lateral tegmentum.
Internuclear Ophthalmoplegia
Nystagmus or paralysis of the contralateral eye during horizontal eye movement.
Interoceptive homeostatic system
The lamina I neurons that encode afferent input on the physiological condition of the body tissues, are a major component of this system.
Lamina I
Only neural region that receives monosynaptic input from A-gamma and C primary afferent fibers, which innervate essentially all tissues of the body. It contributes half the spinal input to the brainstem and thalamus.
Lamina V
Neurons in this lamina receive input from both pain and touch fibers. Touch can inhibit the pain neurons.
Layer VI in sensation
Send connections back to the thalamus. 3rd columnar organization?
Lock syndrome
Bilateral infarction in the paramedian arteries in the base of the pons causes paralysis but does not affect consciousness.
Locus ceruleus
Involved in sympathetic response, uses NE. Releases NE on the spinal cord that depresses ascending pain information.
Low threshold afferents
These neurons have large axon diameters and are the first recruited during electrical stimulation.
Drug used to induce osmotic diuresis and reduce intracranial pressure.
Medial longitudinal fasciculus
Primary pathway by which the vestibular nuclei project to the eye muscle nuclei (3, 4, 6). Damage can result in loss of coordination of eye movement. Located near the cerebral aqueduct in the midbrain, CNVI nucleus in the caudal pons, and the reticular f
Meissner's corpuscles
Rapidly adapting receptors near the skin surface that are responsible for detecting less intense dynamic stimuli like flutter. In general they are good at sensing the beginning and ending of stimuli.
Merkel's discs
Slow adapting receptors that are responsible for sensing continuous levels of skin indentation.
Mesencephalic nucleus of V
Nucleus responsible for proprioception from muscles of mastication.
motor nuclei
hypoglossal nucleus, dorsal motor nucleus of the vagus, and the nucleus ambiguous. Note: the cells of the nucleus ambiguous are in a slightly different location due to embryological migration.
Motor of V
Associated with trigeminal nerve. Muscles of mastication.
A factor from muscle fibers that may be important in the maturation of motor neurons.
Neurogenic edema
Activatoin of afferent C fibers evokes the antidromic release of peptide neurotransmitters (substance P, neurokinin A) from peripheral endings in normal and inflamed tissues as well as at sites of nerve injury. This triggers plasma to leave postcapillary
A factor from motor neurons that has been found to be responsible for the upregulatin of local AChR transcription. This compound is also important in some CNS synaptic receptor clustering.
NMDA receptors
These types of receptors in the dorsal horn are implicated in central sensitizatoin.
Nucleus ambiguous
Associated with cranial nerves 9, 10, and 11. Provides motor (voluntary) to larynx, pharynx and palate. Branchial muscles of throat.
nucleus basilis of Meynert
Area that provides cholinergic innervation to most of the cerebral cortex. Important in reinforcement. Provide a temporal marking.
occulomotor nerve
Its nucleus lies in the rostal midbrain in the same location as the trochlear and hypoglossal nuclei, but more rostral. It exits between the peduncles, and has parasympathetic contributions from the Edinger-Westphal nucleus.
Occulomotor nucleus
Eye muscles except lat rec. and superior oblique.
olfactory receptor cells
Ciliated bipolar neurons that have a life span of 30-60 days.
Pacinian corpuscles
Relatively deep rapidly adapting skin receptors. Good for detecting vibration, beginning and ending of stimuli. Have a larger receptive field than shallower receptors.
parabrachial area
Neurons in this area of the brainstem respond to most types of noxious stimuli and have large receptive fields that can include the whole body surface. May connect to parts of the brain concerned with the emotional or affective aspects of pain.
Paramedian arteries
Blood supply for the corticospinal and medial lemniscus systems.
Abnormal sensation that is not unpleasant.
Path of taste
Specialized receptor cells separate from the neuron -> afferent nerves (7, 9, & 10) with cell bodies in the appropriate sensory ganglia -> primary axons enter the solitary tract and terminate in the rostral part of the solitary nucleus within the rostral
Perception of smell
Receptor cell goes through the cribiform plate to the olfactory bulb. For the cortical pathway, the fibers go to the piriform cortex which is the uncus and the entorhinal cortex where it is processed, projected to the thalamus, and sent on the the orbitof
Periaqueductal gray matter
Activated by mu opiate receptors, recieves input from diverse brain regions including cortex, hypothalamus and reticular formation, excites neurons in two brainstem nuclei (raphe magnus, and locus ceruleus), these nuclei project axons to the spinal cord a
PICA infarction
Effects of this are seen in the rostral medulla's nucleus ambiguous, caudal portion of the spinal trigeminal nucleus, spinothalamic tract, and descending sympathetic fibers from the hypothalamus. Clinical manifestations include: Horner's syndrome, and lo
Pontine reticular formation
This area is involved in modulation of upper and lower limb muscle contractions. Lesions caudal to red nucleus that damage cortical control of this are lead to decerebrate rigidity (extended arms, and extended legs)
Posterior parietal cortex
An association area, deficits in this are produce agnosia,e.g. astereognosis and neglect.
Primary somatosensory cortex (S-I)
Areas 3a, 3b, 1 and 2. Receives input from the VPM and VPL thalamic nuclei (mostly 3a and 3b which then project to areas 1 and 2). Larger receptive field for neurons in this region due to convergence of input.
Principle nucleus V
Associated with trigeminal nerve. Discriminative sensation from the face. Has second order neurons for discriminative touch. Contains the terminations of low threshold primary afferent fibers, and axons that terminate in the VPM. Mediates fine touch and
pronator drift
Type of movement in extended arms that suggests a lesion to the corticospinal tract.
Pyramidal cells
These neurons in largely in lamina 2* and 3 receive connections from stellate neurons (2nd connection in columnar organization) They in turn fire action potentials all over the place including horizontally to columns that share physiological properties.
Radial nerve
Nerve associated with Saturday night paulsey.
Red Nucleus
This nucleus of the rostral midbrain sends axons to the cervical spinal cord, stimulation leads to arm flexion. This projection is under cortical control to some extent. Lesions that disrupt cortical control (motor cortex, internal capsule) lead to decort
Reticular formation
A scattering of nuclei in the brain stem tegmentum that uses monoamine neurotransmitters, not involved in data relay. There are very large projections that are involved in the mediation of function. This area is important in consciousness.
Salivatory nuclei
Associated with cranial nerves 7 and 9, provides parasympathetic innervation for salivation.
Silent nociceptors
Become responsive to stimuli in the presence of inflammation, but are normally not activated by other noxious stimuli. Constitute 1/3 of nociceptors.
Solitary nucleus
Taste (rostral), visceral (caudal). Associated with CNs 7,9,10.
Spinal nucleus of V
Associated with 5, 7, 9, 10. Provides pain and temp. Sensation from the face. The second neurons involved in pain, light touch, and temperature sensation from the face have their cell bodies here.
Spinal trigeminal ganglia
Site of the cell bodies for 1st order neurons involved in sensation of pain, light touch, and temperature from the face. Corresponds functionally to the dorsal horn laminae I and II. Axons that terminate as the anterolateral system.
Spinohypothalamic tract
Projects to hypothalamic autonomic centers thought to be activated by neuroendocrine and cardiovascular responses.
Spinomesencephalic tract
Projects to periaqueductal gray matter, a major opiodergic pain modulating center.
spinoreticular tract
Includes projections to the nucleus reticularis dorsalis, a brainstem nucleus putatively involved in the antinociception produced by acupuncture.
Spinothalamic tract
Receives A-beta, A-gamma, and C fiber input, responds to a wide range of stimuli, mediates transmission of pain, temperature and crude touch. Terminates in the brainstem, intralaminar thalamic nuclei, and VPL thalamic nucleus.
Stellate neurons
Thalamus VPL and VPM project to these neurons in layer 4 of the cortex. They send axons and dendrites vertically to pyramidal cells (2nd connection). This is the 1st connection in columnar organization.
STT VPL neurons
Characteristics of neurons in this region include: Multiple sensory input to a single neuron (polysensory convergence); large receptive fields;response variability, i.e. neurons can alter their receptive field size, firing intensity and modality of respon
substantia gelatinosa
A long column of cells that becomes the spinal trigeminal nucleus in the medulla. AKA, rex lamina 2.
This condition is an example of the "cells that fire together wire together rule", since the fingers aren't separated they are represented together until surgical separation.
Axon growth is dependent on actin filaments in the lamillopodia and filopodia. The actin filaments are stabilized by this protein.
Means sausage... This is associated with conduction block neuropathy. The other type of neuropathy is demyelinating.
TRPM8 Receptor
Found in a distinct sub population of neurons it is activated by cold and the cooling agent menthol.
TRPV4 channels
Essential for the normal detection of pressure and as a receptor of the high threshold mechanosensory complex.
Component of microtubules that is transported at 1-5mm per/day. Membrane vessicles move much faster 400mm/day.
Caused by lesion to the reticular formation, both cerebral hemispheres, or all three.
Vanilloid receptor (VRL)
Activated by capsaicin and other vanilloids and is responsible for moderate thermal nociception. Non-selective cation channel with a thermal activatoin threshold of ~43 degrees C.
Vanilloid receptor-like (VRL-1)
Mediates high-threshold heat responses in Agamma afferents. It is not responsive to vanilloid compounds, but can be activated by noxious thermal stimuli with threshold of ~52 C.
ventral tegmental area
Region medial to the substantia nigra that sends dopamine containing neurons to the ventral part of the striatum including the nucleus accumbens. This system is less involved with motor control than with emotional state.
Ventral trigeminothalamic tract
Second order neurons involved in the sensation of light touch, pain, and temperature from the face deccusate and send their axons up here.
Visceral parasympathetic efferent nuclei
dorsal motor nucleus of the vagus, salivatory nuclei, and edinger wesphal nucleus of cranial nerve 3.
The spinocerebellum division is made up of the vermis and regions that are just lateral to the vermis. It is called the spinocerebellum because it is the only portion of the cerebellum that receives sensory afferents from the spinal cord (it also receives
Rhomberg test
The patient stands with feet together, arms crossed, head bent back, and eyes closed. To remain stading while doing this, must have two of the following: joint position sense, an intact vestibular system (CNVII, CNVIII, MLF, nuclei 3-6, and cerebellum),
A monosynaptic spinal reflex that is mediated by the muscle spindle receptor.
Twitch contractions
The results of a single action potential traveling down a motor unit. There are two main properties, amplitude and time to peak (speed of contraction, which is more important for classification).
Tetanic contraction
This is the maximum force output, produced by the repetative stimulation of the motor neuron producing a train of APs. Under these conditions the Aps fuse together and you can't distinguish them, you get a square force output. Properties include amplitud
Rheobase current
Inject current pulses of increasing intensity until an action potential occurs. The current needed is an inverse index of excitability.
This happens after an action potential. The duration is inversely related to the maximum firing frequency. Longer duration = lower maximum firing frequency. Longer duration is characteristic of the most excitable motor neurons. This is based on calciu
Slow motor units (S)
These motor units have a relatively slow twitch time and small twitch force, but they are also slow to fatigue. Hence they are good for sustained movement. They have a low threshhold of excitation, slow myosin and oxidative metabolism. Lots of blood ves
Fast fatigueable units (FF)/ Type Iib
Motor units that produce the largest output, they contract very quickly and come on at a very high frequency, they have to come on at a high frequency because the twitch contraction time is very brief. They can only sustain contraction for minutes. These
Fast fatigue-resistant units
These are the midway units. They produce a moderate level of force for a moderate level of time.
Interference pattern
When you have a graded voluntary activity that eventually recruits FF units you get this on the EMG.
Rate modulation
When a motor unit is recruited it only generates 15-20% of it's maximum force. More force is generated by increasing the frequency of firing for a particular motor neuron. This accounts for 85-90% of force generation.
Opiate receptors
Mu receptors are found in the PAG and can induce analgesia, Mu receptors are also involved in controlling the threshold of micturition. Kappa receptors conrol the urethral sphincter, and delta receptors control the magnitude of bladder contraction.
Central pattern generators
If you completely transect the spinal cord, then put animal on a treadmill and support them, after a few weeks you get coordinated locomotion. This indicates a pattern generator. Adding NMDA also produces patterned motor output. Pattern can happen with
Force response
This response is composed of two parts: intrinsic mechanical properties of the muscle, and the stretch reflex.
Stretch reflex
This is important in actions that require the active lengthening of muscles. Sensory afferent goes on to and the through the dorsal roots to the dorsal horn and on to synapse on a motor neuron and back to the muscle. It can be blocked through reinnervat
Interuption of the lateral descending system from MI
Paralysis (loss of voluntary movement) or paresis (weakness of voluntary movement) of the affected limbs, most evident in the hand and fingers. Even after the partial recovery of strength, independent control of the digits and fine movements of the hand
Interuption of the medial descending system
"Hemiplegic posture of contralateral limbs: arm may be held flexed at the elbow, and leg is extended.
Large fibrosensory neuropathy
Large myelinated sensory axons coming from muscle spindles, golgi tendon organs, and mechanoreceptors become demyelinated. This can be caused by B6 toxicity. It leads to inability to move through space with balance despite the presence of normal muscle
Tonic neck reflexes
The spindle receptors in the neck muscle have influence over the rest of the spinal system.
Syptoms associated MCA stenosis (entire region)
Hmiplegia, hemisensory loss, Gaze preference, global aphasia (left hemisphere), and neglect syndrome.
Symptoms of MCA superior division stenosis
Hemiplegia, hemisensory loss, conjugate gaze preference, contralateral neglect, brocca's aphasia.
MCA inferior division stenosis symptoms (dominant side)
Wernicke's aphasia, hemianopia, and agitation.
Symptoms of MCA inferior division stenosis (non dominant hemisphere)
Confusion, agitation, hemianopia, and poor drawing/copying.
Symptoms of proximal basilar artery stenosis
Quadriparesis, hemiparesis, psudobulbar palsy, abnormal eye movements, pupillary abnormalities, and reduced level of consciousness.
Symptoms of distal basilar artery stenosis
Pupillary abnormalities, occulomotor abnormalities, behavioral abnormalities.
Symptoms of Basilar artery stenosis with thalamic involvement
Decreased alertness, amneia, sensory abnormalities.
Vertebral artery problems
Vertigo, nausea/vomiting, diplopia, nystagmus, hoarse voice, and ataxia from damage to the cerebellum.
Symptoms associated with the posterior cerebral artery
Hemisensory loss, memory disturbance, naming difficulties, hemianopia, hemiachromatopsia, alexia without agraphia, visual agnosia, headache in the ipsilateral orbit or forehead.
Symptoms associatated with bilateral PCA problems
Cortical blindness, memory loss, and agitation.
Includes the caudate nucleus and putamen. Cortical excitation of this area via glutamate excites inhibitory connections using GABA to the Gpi and substantia nigra activating inhibitory
Cortex-BG-Thalamo-cortical circuit
The cortex projects to the BG(striatum to activate neurons using glutamate). BG then inhibits the thalamus, blocking sensory inputs that would otherwise excite the cortex.
Golgi tendon organs are…
A Ib afferent that infiltrates a tendon, where it loses its myelination. The afferents firing is increased in response to tension in the tendon, this leads to stimulation of a Ib inhibitory interneuron that synapse on the motorn neuron. In antigravity m
A large gelatinous, calcified structure that sits on the alpha helical cilia in the utricle and saccule. Due to its relatively large mass movement causes it to exert torsional force on the cilia, either depolarizing it or hyperpolarizing it by leading to
Housed in the ampullae of the three semicircular canals. These structures are analagous to the otoconia of the utricle and saccule. They are part of the same signal transduction pathway as the otoconia.
Caloric test
The ear is irrigated with warm or cold water to induce convection currents in the endolymph of the vestibular system. This leads to eye movement if the vestibulo-occular reflex is intact.
MI motor cortex (area 4) layer 4
10% of outputs are large pyramidal cells with ascending dendrites to layers 1-3 and axons that descend to the spinal cord and brainstem. The remaining 90% of output comes from smaller neurons. This is the thickest layer of MI.
Cerebellar loop
This circuit recieves inputs from the inferior olive that came from higher order areas. These cerebellar inputs feedback into the Thalamus and eventually relay to the motor cortex. Functions include: error correction, turning off muscle agonists/turning
Basal Ganglia loop
Motor cortex -> striatum/globus pallidus -> Motor cortex. This circuit orders complex movements, and gates movements such that they happen at the appropriate time.
Supplementary motor cortex
Area anterior to the primary motor cortex (medial area 6) that receives input from cortical visual association, areas, from memory areas, and from general movement planning areas; this region is interconnected between the hemispheres and thus can coordina
Cingulate motor area
Area that runs along the cingulate gyrus on the medial side of the brain. It receives input from the limbic system and thus is concerned with motivation and emotion. Outputs go to the brainstem, spinal cord, and primary motor cortex.
Lateral Premotor Cortex
Lateral area 6. Recieves inputs from visual areas of the parietal lobe and from somatosensory association areas, helps project a limb into space.
Primary motor cortex/MI/Area 4
Receives inputs from CMA, SMA, and premotor cortex as well as the somatosensory cortex, posterior parietal lobe (area 5), and the basal gangia and cerebellum (via the thalamus).