Figure 4.

Tracer in CSF spaces flows faster under isoflurane than under K/D. (a) Example of regions of interest used to calculate the speed of tracer across the ventral surface of the rat brain. Each region is a 0.16 mm thick disk positioned perpendicular to the direction of the flow. (b) Kernel density plots of the time and space derivatives of tracer concentration in the ventral surface of the rat brain and the best fitting line. Each level (including white) contains 20% of the data points. Supplemental figure 5 contains linear regression fit for each experiment. (c) Bar plots showing a significant difference in the flow speed of tracer across the ventral surface of the rat brain under K/D and isoflurane. (d) Diagram of the rat head and spine showing the time of arrival in several regions. Time of arrival is defined as when the concentration in a region reaches 10% of the maximum recorded concentration in the region. (e) Comparison of the tracer arrival times for K/D and isoflurane in several regions of the rat brain. Error bars are standard deviation. K/D: ketamine-dexmedetomidine; iso: isoflurane. Two-sided independent t-test, * = P < 0.05, ** = P < 0.01, *** = P < 0.001.