BOLD, CBV, and CBF FMRI of Caudate Putamen in Rat Brain During Noxious Electrical Stimulation: Its Negative Hemodynamic Response to Neural Activities

Fuqiang Zhao¹, Denise Welsh¹, Mangay Williams¹, Alexandre Coimbra¹, Mark O. Urban², Richard Hargreaves², Jeffrey Evelhoch¹, Donald S. Williams¹

In central nervous system, neuronal activity generally leads to increases in local venous blood oxygenation level (BOLD), cerebral blood flow (CBF), and cerebral blood volume (CBV). However, previous studies have reported that the neural activity in rat caudate putamen (CPu) during noxious electrical stimulation (NES) of paws causes BOLD and CBV decreases. To further understand the specific hemodynamic response in this anatomical structure and its temporal characteristics, BOLD, CBV, and CBF fMRI studies were performed in a rat brain slice containing the CPu. Our results suggest that the neural activity in the CPu during NES causes decreases in CBV and CBF, and an increase in CMRO2 which lasts >2 minutes after stopping the NES.