On itsnicethat.com, you can find out more about the project
Here is a small making-of video of the series. What you see in the first few seconds is the ferrofluid resting above the magnet. Thats why you see those spikes, which are caused by the attraction and repeal of the magnetic particles inside the liquid. Then, different tones of water colour are injected into it with the aid of a syringe. The ferrofluid starts to form channels around the colours, creating these brain-like structures.
For more of Fabian Oefner’s work, please visit fabianoefner.com