Axonal growth is a key mechanisms of neural circuit formation. In the developing brain, neuronal axons (and dendrites) grow out along reproducible paths via growth cones at their tips. How do growth cones advance and navigate? Single splayed microtubules (MTs) push from the axon into the actin-rich periphery of growth cones, essentially powered by polymerisation processes at MT plus ends. Upon stabilisation, such MTs guide bulk elongation of axonal MTs, thus elongating the axon. External guidance cues influence the directionality of these events.From other sources: These growth processes are constant and fast. Axons change shape noticeably within a minute or so. Well, didn't really need to ask, did I? Nature is always there first. Endlessly astonishing.
Labels: Grand Blueprint
Polistra was named after the original townsite of Manhattan (the one in Kansas). When I was growing up in Manhattan, I spent a lot of time exploring by foot, bike, and car. I discovered the ruins of an old mill along Wildcat Creek, and decided (inaccurately) that it was the remains of the original site of Polistra. Accurate or not, I've always liked the name, with its echoes of Poland (an under-appreciated friend of freedom) and stars. ==== The title icon is explained here. ==== Switchover: This 2007 entry marks a sharp change in worldview from neocon to pure populist. ===== The long illustrated story of Polistra's Dream is a time-travel fable, attempting to answer the dangerous revision of New Deal history propagated by Amity Shlaes. The Dream has 8 episodes, linked in a chain from the first. This entry explains the Shlaes connection.