INTRODUCTION: The chinchilla animal model is widely used to study the function of the auditory system. The location of auditory cortex in the chinchilla has previously been determined both electrophysiologically and by optical imaging of intrinsic signals. The spatial resolution of functional imaging techniques which rely on changes in the BOLD (blood oxygen dependent level) signal to create images of activity (i.e., fMRI and optical imaging) are ultimately dependent on the resolution of microcirulatory control mechanisms. For example, in response to pure tone auditory stimuli, functional resolution (within cortex) of approximately 400 um has been demonstrated using optical imaging. To better understand the limits of functional imaging the present study was undertaken to explore the structure and properties of the arterial supply within auditory cortex.
METHODS: Plastic casts of the cerebral vasculature were prepared by cannulating the ascending aorta, incising the right atrium and then perfusing 50 ml heparinized PBS followed by 20 ml of Batson's #17 resin.