fMRI mapping of the visual system in the mouse brain with interleaved snapshot GE-EPI.
The use of functional magnetic resonance imaging (fMRI) in mice is increasingly prevalent, providing a means to non-invasively characterise functional abnormalities associated with genetic models of human diseases. The predominant stimulus used in task-based fMRI in the mouse is electrical stimulation of the paw. Task-based fMRI in mice using visual stimuli remains underexplored, despite visual stimuli being common in human fMRI studies. In this study, we map the mouse brain visual system with BOLD measurements at 9.4T using flashing light stimuli with medetomidine anaesthesia. BOLD responses were observed in the lateral geniculate nucleus, the superior colliculus and the primary visual area of the cortex, and were modulated by the flashing frequency, diffuse vs focussed light and stimulus context. Negative BOLD responses were measured in the visual cortex at 10Hz flashing frequency; but turned positive below 5Hz. In addition, the use of interleaved snapshot GE-EPI improved fMRI image quality without diminishing the temporal contrast-noise-ratio. Taken together, this work demonstrates a novel methodological protocol in which the mouse brain visual system can be non-invasively investigated using BOLD fMRI.
UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK.
Arun
A
Niranjan
UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK; Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK.
Isabel N
IN
Christie
Department of Experimental Psychology, University College London, London, UK.
Samuel G
SG
Solomon
UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK.
Jack A
JA
Wells
UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK.
Mark F
MF
Lythgoe
D000818:Animals; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D005829:Geniculate Bodies / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008810:Mice, Inbred C57BL; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D013477:Superior Colliculi / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
Mouse; Negative BOLD; Visual cortex; fMRI