Chiao-Chi V Chen1,2,
1Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan; 2Functional & Micro-magnetic Resonance Imaging Center, Academic Sinica, Taipei, Taiwan; 3Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, United States
Negative fMRI response is less well understood in fMRI studies. Elucidating its coupling and uncoupling to brain activity is important for referring the negative fMRI signals to a correct source. Afferent activity and local processing is recognized as the activity source of fMRI signals, but their role in negative fMRI signals with respect to neurovascular coupling and uncoupling remains unclear. The present study characterized a negative fMRI response occurring in the striatum, triggered by nociceptive electrical stimulation. We found that the negative fMRI response was uncoupled to the local neuronal activity yet coupled to afferents via neurotransmission.