Laser-Doppler flowmetry utilizing a thinned skull cranial window preparation and automated stimulation

For several decades, cranial windows have been used to investigate questions relating to cerebral blood flow and its regulation. In general, these techniques have utilized either 'open' cranial windows for the direct observation of the intracranial vasculature, or 'closed' cranial windows in which the skull and dura are removed and replaced with a clear seal, such as a coverslip. Here we describe a method of studying blood flow responses elicited by the physiological stimulus of whisker movement while using a 'thinned skull' cranial window created over the rat whisker-barrel cortex. This method employing an automated whisker stimulator coupled with laser-Doppler flowmetry focused through the thinned skull cranial window, is less invasive than other cranial window techniques, and allows for the study of the effects of stimulation parameters and systemically administered compounds on whisker movement elicited blood flow responses. Automated whisker stimulation and data collection also allow for precise temporal averaging of laser-Doppler measured responses, leading to increased precision in determining the true shape of the evoked blood flow response pattern.