As you lay your head down to sleep tonight and dream all things weird and wonderful, scientists think your brain is going through a gentle rinse cycle, washing away a day’s worth of toxic by-products in preparation for a new day of thinking ahead.

But the mechanisms behind this neurological cleansing system have yet to be described in detail.

Now researchers from the University of Copenhagen have applied a suite of technologies to map the subtle rise and fall of neurotransmitters, blood volume, and spinal fluid in mice as they go about their day.