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74 Cards in this Set
- Front
- Back
Motor Cortex location in frontal lobe
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back end of frontal lobe
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Precentral Gyrus
Premotor Cortex Supplemental Motor Area |
motor strip, primary motor cortex
PreMC-in front of precent. refines motor mvmt SMA-top, medially- refines motor mvt |
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Raw Motor output
Refineries |
Precentral Gyrus (motor cortex)
Basal Ganglia and Cerebellum |
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what type of neruons are in the CST and motor cortex areas?
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Upper Motor Neurons
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where is the CST at the decussation of the pyramids?
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CST winds up in the dorsal part of lat funiculus
goal=talk to alpha motor neuron |
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Homunculus
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mouth- lateral
feet/legs- medial Big Lips/Face/Hands-a lot dedicated to these parts |
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3 Homunculi
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1. precentral gyrus
2. postcentral gyrus 3. Premotor Cortex |
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Brodman's Areas
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dfft parts of cortex w/ dfft histological differences
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Neocortex
3layered piece |
cortex is primarily 6 layers
Hippocampus, more ancient |
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Layer 5
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most important
contains Betz cells main pyramidal cells, give rise to CST |
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Brodman Area 4
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precentral gyrus (primary motor cortex-PMC). main motor output.
CST/CBT control individual mvmt of muscles |
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Force of Contraction and Timing of Contraction are dependent on?
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relative to what is happening in the cortex
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Force
Timing |
freq of firing of individual Betz Cells
M1 UMN from precent gyrus. neuron to muscle contraction has lag (ms) |
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Brodman Area 6
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Pre Motor Cortex (PreMC)
refines motor mvmt, controls complex mvmt |
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Timing: PreMotor Neruon fires when?
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before the M1 (main motor neuron)
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Main outputs of PreMC (area 6)
what inputs INTO PreMC |
1. Main=Area 4
2. some directly to ventral horn 3. some to reticulspinal path -axial and prox musc *Posterior Parietal Cortex |
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Fxn of Post Parietal Cortex
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1. input into PreMC
2. fxn in Tone (Gamma MN) 3. goes to reticulospinal neurons |
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Supplemental Motor Area(SMA)
-location, brodman area |
medial aspect of hemisphere
still brodman area 6 -just like PreMC |
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function of SMA (MII) neurons
anomaly of SMA |
motor planning
precedes firing of PreMC just thinking of moving will fire MII |
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what is the SMA in close prox to
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the limbic lobe
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Flow of Timing of motor firing
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1. SMA (MII)
2. PreMN 3. MI 4. Contraction |
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Primary Motor Cortex neurons (PMC) receive input from
5/7 |
1. SMA (MII)
2. PreMC 3. Primary Sensory Areas 4. Post Parietal 5. Thalmus VA/VL -also receives 6. Cerebellum 7. Basal Ganglia |
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UMN
LMN MOTOR UNIT |
in cortex
in ventral horn LMN+all the muscle cells it innervates |
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EMG can detect
at rest max act |
diseases of LMN and UMN
recording needle in muscle itself bomp,bomp,bomp shhhhhhhhhhh |
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Denervation
ALS |
neve damaged or alpha motor neuron is dead
can have damage to both LMN/UMN |
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what happens when a muscle cell is denervated?
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secrete substances that attract nearby intact nerve endings
other nerves can reconnect that muscle cell |
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if renervation doesnt happen, 2 things are possible....
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1. fibrillations
2. fasiculations |
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Fibrillation
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muscle atrophy/shrinkage occurs
use EMG NOT visible to naked eye |
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Partially denervated muscle
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at rest, get fibrillations (positive sharp waves)
tic intermittent at rest NOT visible need EMG |
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sick/dieing motor neuron that is STILL connected to muscle...
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muscle will be irritated-fires on its own
==>Fasiculations |
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Fasiculations
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visible to naked eye
represent irritated/sick motor unit do NOT need emg seen in ALS or Polio before you see atrophy |
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when do i need an EMG?
when do i not need an EMG |
to see fibrillations
to see fasiculations |
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Fasiculations of the Tongue
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seen in ALS
skeletal hands very weak will become a serpintine tongue after wasting |
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NMJ
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no phys contact
rel Ach |
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what does the muscle tissue do to accomodate the NMJ?
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microscopic indendations to inc surface area of receptors
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what happens to jxnl folds in M.G.?
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they flatten out
amt of Ach rec is decreased autoimmune disease to Ach rec |
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Botulinum Toxin
large portion small portion |
clostridium botulinum
fools the buton into taking it in protease that eats a docking protein |
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botulinum toxin
Type A Type B |
all small portions are protenacous
cut synaptobrevin(VAMP) cut SNAP25 |
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effects of botulinum toxin..
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neuron cant rel Ach anymore
terminal does not fxn grows rootlets to reattach |
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symptoms of LCST lesion
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contralateral body weakness
lose fine motor control lose contralateral lower face lose contralateral tongue (CBT) spare axial muscles(VCST) |
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Lesion to PreMC
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slow jerky movements
difficult in visually guided tasks *very rare* |
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what usually accompanies a preMC lesion?
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a concurrent lesion to PMC
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Lesion to SMA results in
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Apraxia
losing your motor memory |
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What is perseverative behavior and what is it associated with?
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repeating motor tasks over and over
assoc w/ lesions to SMA |
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Normal Pressure Hydrocephalus
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NPH=Apraxia
pressure is abnormal during sleep pressure bangs up against ventricles and hits lets/bladder |
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3 Ws of NPH
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1. wacky- forgetful, not psychotic
2. wet- loss of bladder fxn 3. wobbly- more of an apraxic gate, espec when starting to walk |
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what do NPH patients appear to be like? exception....
whats another name for apraxic gate? |
Parkinson's Patients
NO TREMOR magnetic gate |
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treatment for NPH
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put a shunt in to relieve night-time CSF pressure spikes
small window of opportunity |
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Lesion to Post Parietal Cortex(PPC)
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rare to have motor complaints if just PPC. but usually with PMC
Hemi-neglect arm/leg ususally nondominant hemi, so left hand neglected |
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Parietal Lobe controls what
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3-Dimensional Space map
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Premotor for eyes is called what?
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Frontal Eye Fields (FEF)
infront of homunc for eyes |
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what does the FEF talk to?
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to PPRF on opp side
PPRF talks to ipsiVI + contraIII allows eyes to work laterally |
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what gets from PPRF to opposite CNIII?
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MLF-medial long fasiculus
lesion in lft MLF->problems w/ left CNIII |
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look laterally, problem with medial rectus in lft eye, converge and everything is ok. what is this called?
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Intranuclear opthlmolegia(IOP)
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usual areas affected in MCA stroke
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1. FEF
2. precentral gyrus 3. postcentral gyrus |
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is person is looking AWAY from paralyzed side, what does that mean?
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they are looking toward damaged cortex
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if damage is in pons w/ pyramidal fassicles affected, person is looking toward damaged side, why??
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if lesion in Lft Pons, hitting Lft CST. rt side paralyzed
look to right b/c lft PPRF is damaged- lft lat rectus gone and lft MLF is damaged- rt med rectus is gone--->therefore eyes look right |
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Posturing
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associated with damage right after pathways have left the cortex
Bilateral Herniation-pushing brain down decerebrate or decorticate |
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Decorticate
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happens first. closer to cortex
motor lesion of IC or cortex spastic hemiplegia flexion 'looks like an O' |
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Decerebrate
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lesions b/w red nuc and vestib nuc
gamma rigidity hyperpronation and extension |
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is the CST all motor?
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NO
40% Betz cells from Area 4 20% from Area 6 40% from PPC *some sensory is in CST |
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CST path
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post limb of IC
ducussates at pyramidal dec 80-90% crosses to lateral funiculus 10-20%stays Ipsi in ventral funiculus down to ventral horn of SC |
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Corticobulbar Tract (CBT)
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Area 4 and Area 6
pass thru Genu of IC goes to all motor nuclei in brain stem gets most bilaterally |
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lesion of CBT
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lower face paralysis
sometimes contralat tongue |
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Corticorubral Tract
what is the main output of CRT? |
Areas 4+6
UMN for Red Nuclei -part of Mollaret's Triangle Rubrospinal Tract |
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Rubrospinal Tract
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crosses and goes to
1. torso 2. head 3. upper arm facilitates upper limb flexor MN |
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where does the RubroST synapse
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on interneurons in Rexed Laminae 5, 6, and 7
primarily of cervical cord its a little VENTRAL to LCST in lateral funiculus |
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what pathway is cervical dystonia associated with?
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person's head is twisted
Rubrospinal Tract |
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Corticoreticular pathway
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Area 4+6
post limb of IC synapse on pontine and medullary reticular fomrations Bilat |
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Reticulspinal Tract synapses where
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Rexed Laminae 7, 8, 9
goes to torso, head, and forearm alphaMN |
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Primary involvement of Reticulospinal tract
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gama tone and reflexes
preganglionic sympathetic neurons in CV regulation -via talking to IMLCC |
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what is near the Reticulospinal tract in the SC
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overlaps with Spinothalamic Tract
pain illicits racing heart rate and inc BP |
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which pathways have direct control over movement?
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Corticospinal (CST)
Corticobulbar (CBT) Corticorubral Corticoreticular |
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which paths modulate motor performance via neural loops involv cerebellum and BG
relay paths |
corticothalamic
corticostriatal corticopontine |