A patient with a lesion of the brainstem reticular formation presents with persistent coma. The reticular activating system maintains consciousness by projecting to the cortex via which pathway?
- A Corticospinal tract
- B Medial lemniscus
- C Thalamocortical projections ✓
- D Spinothalamic tract
Correct answer: C. Thalamocortical projections
Explanation
The ascending reticular activating system (ARAS) in the brainstem maintains arousal and consciousness by projecting to the cortex via thalamocortical pathways. Lesions of the ARAS or its thalamic relays cause coma. The corticospinal tract is motor, the medial lemniscus carries proprioception, and the spinothalamic tract carries pain and temperature.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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