Right-lateralised central processing for pain of nitroglycerin-induced cluster headache.

Recent functional brain imaging studies with positron emission tomography (PET) suggest a preference of the right hemisphere, especially the anterior cingulate cortex (ACC), in affective processing of the clinical pain syndromes. We have investigated the central processing of cluster headache (CH) attacks provoked by sublingual nitroglycerin (NTG). In the cerebrum, provoked CH activated the ACC and the temporopolar region of the right hemisphere in addition to other regions. The regions activated in the ACC (Brodmann area (BA) 24 and 32) are involved in affective/cognitive processing of pain and willed attention. Our study discloses the preferential role of the right hemisphere in attributing emotional valence and attention to the suffering of pain. The findings support the theory of a right hemispheric specialisation in the mediation of withdrawal-related negative affect. The divergence of the distributed central processing between provoked cluster headache attack and experimentally induced acute pain indicates different central mechanisms for different types of pain.