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Respect Your Nose

Our language seems to indicate that we think of the world as divided up into things that 'smell' and things that don't. Garbage smells. Groceries don't. A dirty sock smells. A clean one doesn't. That way of talking doesn't give much respect to odors, or to our olfactory system. Once you appreciate the delicacy of our olfactory system's design, ...

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NoseScience
Astronomy

Pluto Is Way Out There

Long considered to be the smallest, coldest, and most distant planet from the Sun, Pluto may also be the largest of a group of objects that orbit in a disk-like zone of beyond the orbit of Neptune ... Continue reading

PlutoIsWayOutThere
Geology

Pyroclastic Flows: Deadly Rivers of Rock

A volcano, during a violent eruption, blasts massive amounts of heated rock fragments, hot gas and ash out vents and collapsing domes. This sudden outpouring of superheated material reaches ... Continue reading

VolcanoFlows
Science

Subrahmanyan Chandrasekhar

NASA's premier X-ray observatory was named the Chandra X-ray Observatory in honor of the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar (pronounced: su/bra/mon'/yon chandra/say/kar). ... Continue reading

SubrahmanyanChandrasekhar
Astronomy

Big Fish

The phrase 'big fish eat little fish' may hold true when it comes to planets and stars. Perhaps as many as 100 million of the sun-like stars in our galaxy harbor close-orbiting gas giant planets like ... Continue reading

BigFish

Neurons

NeuronsUntil recently, most neuroscientists thought we were born with all the neurons we were ever going to have. As children we might produce some new neurons to help build the pathways - called neural circuits - that act as information highways between different areas of the brain. But scientists believed that once a neural circuit was in place, adding any new neurons would disrupt the flow of information and disable the brain's communication system. In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons migrated from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman's findings in the rat brain, and in 1983 he found neural precursor cells in the forebrain of an adult monkey.

These discoveries about neurogenesis in the adult brain were surprising to other researchers who didn't think they could be true in humans. But in the early 1980s, a scientist trying to understand how birds learn to sing suggested that neuroscientists look again at neurogenesis in the adult brain and begin to see how it might make sense. In a series of experiments, Fernando Nottebohm and his research team showed that the numbers of neurons in the forebrains of male canaries dramatically increased during the mating season. This was the same time in which the birds had to learn new songs to attract females.

Why did these bird brains add neurons at such a critical time in learning? Nottebohm believed it was because fresh neurons helped store new song patterns within the neural circuits of the forebrain, the area of the brain that controls complex behaviors. These new neurons made learning possible. If birds made new neurons to help them remember and learn, Nottebohm thought the brains of mammals might too. For some neuroscientists, neurogenesis in the adult brain is still an unproven theory. But others think the evidence offers intriguing possibilities about the role of adult-generated neurons in learning and memory.