DeLahunta Chapter 8 - UMN System Flashcards
Where is the cell body of the pyramidal system in primates, carivores and ungulates?
Motor cerebrocortex
PRIMATES: Precruciate gyrus
CARNIVORES: Postcruciate and dorsal suprasylsvian gyrus + premotor area (somesthetic area)
UNGULATES: Precruciate gyris
Where are the cell bodies of the extrapyramidal system?
Multiple areas in brain:
1)cerebrocortex (motor frontoparietal lobes)
2) basal nuclei
3) diecnephalon nuclei (endopenducular nuclei, zona incerta, subthalamic nucleus)
4) midbrain (substancia nigra, red nucleus)
5) reticular formation
6) pons-medulla-cerebllum (olivary nucleus in medulla)
What is the difference in the pathway between pyramidal vs extrapyramidal system?
Pyramidal - uninterrapted monosynaptic corticospinal pathway from the cerebrum to the spinal cord through the medulla (pyramids)
Extrapyramidal - multisynaptic cortical neurons transversing basal nuclei or brainstem and not going through pyramids to the spinal cord
Which is the exact 3 pathways of the pyramidal system?
A) LATERAL CORTICOSPINAL TRACT
1) Cerebrocortex (giant pyramidal cells - lamina v)
2) corona radiata
3) centrum semiovale
4) internal capsule
5) crus cerebri (midbrain)
6) longitudinalf ibers of pons
7) pyramids of medulla
8) pyramidal decussation (75% crossing in dogs)
9)contralateral dorsal portion of lateral funiculus = lateral corticospinal tract (in dogs: 50% to cervical SC GM, 20% thoracic, 30% lumbosacral)
then synapse to interneuron of ventral grey horn –> GSE LMN
B) CORTICONUCLEAR TRACT
Some axons going to braistem GSE LMN of CNs (part of reticular system)
C) VENTRAL CORTICONUCLEAR TRACT
25% of the fibers of A that did not decussate. Crossing opossite side in the spinal cord – they end in midthoracci SCS –> inteneuron –> GSE LMN
Which are the histologic layers of neocortex from surface to deep?
Lamina I - Molecular –> horizontal neurons of Cajal (project parallel to the surface)
Lamine II -external granular (small pyramidal cells & many stellate)
Lamina III - external pyramidal (medium/large pyraidal cells, few stellate)
Lamina IV- internal granular (small stelates)
Lamina V - internal pyramidal (medium/large pyramidal cells/ small stellates)
Lamina VI - multiform (fusiform) (modified pyramidal cells)
Which are the (telencephalic) basal nuclei?
1) amygdala (limbic)
2) septal nucleis (limbic)
3) caudate nucleus
4) nucleus acumbens
5) putamen (lentiform)
6) globus pallidus (lentiform)
7) claustrum
(..8…) endopenducular nucleus (part that is in the pallidum)
From 3 to 7 along with their white matters (external and internal capsule) is the CORPUS STRIATUM.
Which are the diencephalic extrapyramidal nuclei?
SUBTHALAMUS (only)
1) endopenducular nucleus
2) zona incerta
3) subthalamic nucleus
Which are the extrapyramidal nuclei of the midbrain and rhombencephalon?
Midbrain;
1) substancia nigra
2)red nucleus
Medulla:
3) olivary nucleus
(+) reticular formation part of it.
Which are the clinical sings of lesion in the UMN leading to release of their inhibition (or disinhibition)?
1) seizures
2) decerebrate rigidity (rostral-caudal colliculi in mibrain)
3) decerebellate rigidity (cerebellum)
4) tetanus/tetany
5) myoclonus
6) other MDs
Why pleurothotonus or compulsive circling occur in forebrain disease?
part of the adversive syndrome - tendency to turn or walk to the side of lesion
-specific locatio of the problem is unknown
-but possibly it is a result of interruption in the normal circuity from cerebrocortex to basal nuclei and the thalamus and back to cerebrocortex (frontoparietal area)
-patient is aware of the enrinvoment
-lesion in substancia nigra or nigropallidal pathway may contribute
Which disease of extrapyramidal pathway you know in horses?
Which area affects pathologically
Which is the cause and in which circumstances it happens?
Which are the clinical signs?
Equine nigropallidal encephalomalacia.
bilateral cavitation/ ne-
crosis in the globus pallidum and substancia nigra
consume the plant called yellow star- thistle (Centaurea
solstitialis) or Russian knapweed (Centaurea repens) for a
period of a few weeks
Clinical signs:
-difficulty swalloing/prehension
-spastic paresis of tempormandibular joint, lips and pharyngeal muscles
Diseases that can cause bilateral caudate nucleus lesions in dogs?
1) subacute necrotizing encephalopathy in alaskan husky (leigh-like syndrome)
2) thiamine deficiency
3) carbon monoxide poisoning
4) brain iron
accumulation, as seen with Huntington disease.
Which are parts of caudate nucleus?
Head, body and tail
What is the predominant function of the red nucleus?
fascicilatory activity to the GSE-LMN of FLEXORS –> initiation fo protraction phase of gait
What is the difference between intrafusal and extrafusal muscle fibers?
