Descerebrate vs Decorticate Posturing - USMLE Forums
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Old 01-27-2012
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Neuro Descerebrate vs Decorticate Posturing

In a classic experiment performed by Sherrington in the cat, marked rigidity was demonstrated in a decerebrate preparation. Similarly, an 80- year-old woman displayed rigidity, which resembled that shown in the cat after having a stroke.

The likely location of the stroke is in the
a. Thalamus
b. Hypothalamus
c. Upper midbrain
d. Pons
e. Spinal cord
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Old 01-27-2012
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Default Answer

Source of Question
Neuroscience Pretest Self-Assessment and Review, Seventh Edition


Answer
Rigidity can occur by experimentally producing a decerebrate preparation (i.e., severing the brainstem at the level of the pons) and it appears clinically as well. In both situations, there has to be extensive destruction of brain tissue below the midbrain in the region of the pons, but which spares the medulla.

Descerebrate vs Decorticate Posturing-descerebrate.png
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Old 01-29-2012
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Am I correct in assuming that decorticate is above the level of the midbrain?

What is the relation of all of this to the corticospinal tract? I remember reading somewhere that decerebrate is complete loss of the fibers, while decorticate is incomplete severance of the CST. Why is there the difference in the presentation? In both of them, the innervation to the red nucleus and the rubrospinal tract is reduced- so why are they different?
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Clinical-Signs, Figures-, Neuroanatomy-, Step-1-Questions

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