Background Task-free imaging approaches using PET have shown the posterior hypothalamus to be specifically activated during but not outside cluster headache attacks. Evidence from task related functional imaging approaches however is scarce. Methods Twenty-one inactive cluster headache patients (episodic cluster headache out of bout), 16 active cluster headache patients (10 episodic cluster headache in bout, 6 chronic cluster headache) and 18 control participants underwent high resolution brainstem functional magnetic resonance imaging of trigeminal nociception using gaseous ammonia as a painful stimulus. Results Following trigeminonociceptive stimulation with ammonia there was a significantly stronger activation within the posterior hypothalamus in episodic cluster headache patients out of bout when compared to controls. When contrasting estimates of the pain contrast, active cluster headache patients where in between the two other groups but did not differ significantly from either. Conclusion The posterior hypothalamus might thus be hyperexcitable in cluster headache patients outside the bout while excitability to external nociceptive stimuli decreases during in bout periods, probably due to frequent hypothalamic activation and possible neurotransmitter exhaustion during cluster attacks.

中文翻译：

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丛集性头痛中三叉神经输入后的相位依赖性下丘脑激活

背景 使用 PET 的无任务成像方法显示后下丘脑在丛集性头痛发作期间但不在丛集性头痛发作外被特异性激活。然而，来自任务相关功能成像方法的证据很少。方法 21 例非活动性丛集性头痛患者（发作性丛集性头痛）、16 例活动性丛集性头痛患者（发作性丛集性头痛 10 例，慢性丛集性头痛 6 例）和 18 名对照参与者接受三叉神经痛觉的高分辨率脑干功能磁共振成像使用气态氨作为痛苦的刺激。结果在用氨进行三叉神经痛刺激后，与对照组相比，发作性丛集性头痛患者的下丘脑后部有明显更强的激活。当对比疼痛对比的估计值时，活动性丛集性头痛患者位于其他两组之间，但与任何一组都没有显着差异。结论因此，丛集性头痛患者在发作外的下丘脑后部可能过度兴奋，而在发作期对外部伤害性刺激的兴奋性降低，这可能是由于频繁的下丘脑激活和丛集发作期间可能的神经递质耗竭所致。