The MRI scanner measures this signal difference and displays the activity as a colored area (Figure 1). Diffusion Tensor Imaging (DTI) is a technique that detects how water travels along the white matter tracts in the brain (Figure 2). White-matter tracts connect different parts of the brain and must be protected during surgery. A dye (contrast agent) may be injected into your blood stream.
Dock spiders can swim. A dock spider can actually swim under water and stay submerged for several minutes. It uses air bubbles trapped in the fine hairs on its body under its belly to provide oxygen while it is under water â a bit like a dock spider scuba dive. Dock spiders walk on water.
Spiders are small (with the exception of the Acromantula) eight-legged and eight-eyed creatures. They are very common and come in many species, varying from region to region; all are carnivorous and some are venomous, but for the most part they are relatively harmless and can sometimes be used as a potion ingredient.