BOLD fMRI of the mouse barrel cortex

Introduction: Understanding and identifying the neuronal networks of the cerebral cortex, their temporal properties, their development and plasticity are the focus of many functional imaging studies both in humans and rodents (1). In the mouse, a noninvasive method to study functionally the neural network of the barrel cortex would open the possibility to investigate the neurophysiological mechanisms responsible for plasticity during development, learning and lesion in normal and transgenic animals. BOLD functional MRI studies in mice have been difficult until now (2). This difficulty is linked to the maintenance of an appropriate physiology of the mouse during the fMRI study which has been an important topic of investigation recently (2, 3). Moreover, the small structures of the mouse brain require the use of high field strength (2) at the expense of increased susceptibility artifacts in the areas of interest or the use of dedicated cryogenic RF coils (3, 4) in order to increase the signal to noise ratio (SNR). In the present work, BOLD activations in the mouse barrel cortex under isoflurane anesthesia have been detected at 9.4T and 14.1T.