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.
This fascinating arthropod, also known as the water spider, is quite similar to other spiders in that it breaths air, although it does it in a much more creative way. These spiders spin a web cocoon of silk which they then fill up with air creating a bubble that they can take with them underwater. And due to a mostly sedentary life this spider is able to make the most of its oxygen only needing to come up about once a day or even less to replenish its air supply.
Many swimming pool owners in Australia find funnel-web spiders in their pools at some point. These spiders cannot jump or live in the bottom of a pool for very long, but they can be deadly to people. Chlorine in the pool water eventually kills them after several hours of swimming around underwater. Air bubbles stick to their leg hairs, which helps them breathe for awhile.