This type of MR scan exhibits gray-white brain tissue contrast. White brain tissue (fibers) appears bright, while the gray matter (where most neurons are located) is darker, and cerebrospinal fluid (liquor) is black. The bright "shell" around the brain is not the skull, but rather the fat layer in the scalp. The provided images have been recorded at 0.67 mm resolution. For more information on this image type see Wikipedia. The complete description of this acquisition has been published in:
Hanke et al. (2014). A high-resolution 7-Tesla fMRI dataset from complex natural stimulation with an audio movie. Scientific Data, 1.