<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: In decoicate animal which reflex is lost?
Options:
A. Hopping and placing reflex
B. Tonic neck reflex
C. Tonic labyrinthine reflex
D. Stretch reflex
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is A: Hopping and placing reflex. Explanation: Removal of the cerebral coex (Decoication) produces decoicate rigidity which is characterized by flexion of the upper extremities at the elbow and extensor hyperactivity in the lower extremities. The flexion can be explained by Rubio spinal excitation of flexor muscles in the upper extremities; the hyperextension of lower extremities is due to the same changes that occur after mid-collicular decerebration. Decoicate rigidity is seen on the hemiplegic side in humans after hemorrhages or thromboses in the internal capsule. Probably because of their anatomy, the small aeries in the internal capsule are especially prone to rupture or thrombotic obstruction, so this type of decoicate rigidity is fairly common. Sixty percent of intracerebral hemorrhages occur in the internal capsule, as opposed to 10% in the cerebral coex, 10% in the pons, 10% in the thalamus, and 10% in the cerebellum.Reference: Ganong review of medical physiology 23rd edition Page no: 247<|im_end|>
