Hello!
We are looking at perfusion maps of activation and deactivation in a group characterized by a chronic symptom, labeled S. When we induce this symptom (sensation) experimentally (and acutely), and run a regression analysis with the intensity of this acute stimulus (A), some of the areas that show a positive correlation with perceived intensity overlap with areas of deactivation induced by A, while areas showing a negative correlation with intensity coincide with (some of the) areas that were activated by A. Did someone encounter a similar situation? How these inverse correlations can be interpreted? Are there any "guidelines"? It would be acceptable or reasonable to interpret that areas that were 'activated' (less perfused) AND their activation inversely correlated with perceived stimulus intensity may have the function to suppress, inhibit or decrease stimulus perception? Interestingly, this feature is mirrored by the positive correlation of deactivation with intensity (in other areas). May this suggest some sort of a negative feedback phenomenon, that manifests 'both sides of the same coin'? (We use ASL for signal acquisition). Your input is greatly appreciated.
Thanks.
Alex
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