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.
Brown Spiders (Loxoscelidae) are also known as the recluse spiders. The best known and most notorious member of this family is the brown recluse that has a violin-shaped pattern on the back of the front body segment. These spiders have only 6 eyes, while other spiders have 8.