Article posted Thursday, August 19, 2010 10:46pm

• How do newborn children become aware of the space around them? In the adult brain there are specific neurons that keep us informed of head direction. Another set of neurons (called “place” cells) tell us where our bodies are in two-dimensional space. And still a third set of neurons (“grid cells”) keep us informed about our position in three-dimensional space. For example, when we visit a specific part of our environment, place neurons fire away in our brains. Grid neurons then update our position in space depending on our movements. All of this happens at the subconscious level, although we can bring our status in space to the conscious level by focusing on these parameters. Neuroscientists have long wondered if babies are born with these spatial orientation pathways already in place, or if they learn about space as they tumble around in their cribs and try to hold their heads upright and directed. Recent studies in newborn rats indicate that head-direction neurons, place neurons, and grid neurons are already in place, although not as fully developed as in adults. If this applies to humans, it means that even in utero the fetus already “knows” something about the environment into which he or she will be born. (Rosamund, et al, as reported in Science, June 18, 2010).

• Don’t believe that all-electric vehicles are part of our “zero emission” energy future. Remember, the batteries of these vehicles must be charged using electricity produced by power plants, most of which burn coal or natural gas. In the Midwest and in the eastern part of the U.S. most power plants burn coal to produce electricity. In these regions, all-electric cars won’t produce carbon dioxide, but the added demand on coal-fired plants to produce electricity to recharge their batteries will release an increased amount of the gas (by as much as 40 percent). On the other hand, in parts of the country where power plants burn mainly natural gas, which is less polluting, use of all electric vehicles will decrease the amount of carbon dioxide released to the atmosphere when nuclear and renewable sources are not considered. (Michael Moyer in Scientific American, July 2010).

• The earliest dragonflies were huge compared with those of today. The oldest dragonfly fossils, dating some 300 million years ago, reveal a giant dragonfly with a wingspan of 2-1/2 feet. It’s theorized that as the level of atmospheric oxygen fell to its present level over time, such large dragonflies would have had difficulty delivering oxygen through the inefficient network of tiny tubes that make up their “breathing” system. Thus they evolved into smaller modern dragonflies; the largest dragonfly today appears to be the Giant Petaltail of Australia, with a wingspan of 6.3 inches. The smallest dragonfly is the Pigmy Dragonfly, found in eastern Asia. It has a body length of only about 0.6 inches.

• Considering the pain involved and the permanence of the procedure, why do so many people have their bodies modified by one or more tattoos? Certainly it’s a social signal of some kind, and more and more people are willing to advertise themselves by turning their skin into a canvas for a tattoo artist. In 1936, Life Magazine estimated that 6 percent of Americans had a tattoo. A Harris Poll in 2003 estimated that the number had risen to 16 percent, and in 2006 A Pew Research Poll found that 36 percent of Americans aged 18-25 had one or more tattoos, and in the 26-40 age group 40 percent had a tattoo. Asked how tattoos made them feel, people listed one of the following: sexy, spiritual, rebellious, attractive, or strong. Are many people sorry they got tattoos? Only about 17 percent said yes (various sources, including, Sex Differences by Linda Mealey, Academic Press, 2000).