Figure 3.

Non cardiac cycle related brain oscillations in brain injury. The upper panel demonstrates a normal Arterial brain compression pulse. The next panel Fast waves which oscillate at high frequencies (8–14 hz). The amplitude is typically high > 2000 AU with symmetry of 940 and 660 nm throughout the cardiac cycle. Spindles also oscillate at high frequencies (10 −14 hz), but are typically brief, just a few heart beats in duration and the amplitude lower than Fast waves. Spikes are typically single brief waves. They are usually independent of the cardiac cycle. Red brain pulse is 940 nm and blue brain pulse 660 nm. The yellow area represents the systolic phase of the cardiac cycle and the white the diastolic phase.