AP Biology class blog for discussing current research in Biology

Author: karbonkim

Out Like a Light: Sleep Switch in Brain Identified

Researchers from Oxford University’s Center of Neural Circuits and Behavior have identified the switch in the brain, which causes sleep, from a study of fruit flies. This switch regulates sleep promoting neurons in the brain. When one is tired and in need of sleep, these neurons will activate. Once you are fully rested, neuron activity will die down. Though this new insight was gained through studying fruit flies, or Drosophila, the researchers believe this information is also relevant to humans. In the human brain, there are similar neurons that are active during sleep and are the targets of general anesthetics that cause sleep. These facts support the idea that humans have a sleep mechanism like that found in fruit flies, according to Dr. Jeffrey Donlea, one of the lead authors of the study. The findings of this study were published in the journal, Neuron.The discovery of this sleep switch is important for a number of reasons like finding new treatments for sleep disorders, but it is just a small piece of the enigma that is sleep. The internal signal, which this sleep switch responds to, is still unknown, as is the activity of these sleep-promoting cells while we are awake. We do not even know why humans and all other animals need sleep.


In spite of these mysterious, scientists do know how the body regulates sleep. Humans and animals have a body clock, which makes us accustomed to the 24 hour cycle of day and night, and a sleep switch, which logs the hours you are awake and causes you to sleep when you need rest. When this mechanism is off or not being used, sleep deficiency increases. The combination of these two is the most likely cause of us sleeping at night.

The significance of this switch in the process of sleep and its relationship to bodily function was found when studying the fruit flies. If they did not sleep, mutant flies cannot regain these lost sleep hours. Sleep-deprived flies are also more likely to nod off and be cognitively impaired. Like sleep-deprived humans, these flies were subject to severe learning and memory deficiencies. In the mutant flies, the researchers proved the insomnia of the flies was due to a broken part of the electrical activity switch, which caused the sleep-inducing neurons to always be off.

Why do you think sleep is important? How is this discovery significant and how do you think this information will be used in the future? Will the mystery of sleep be solved soon?

Photograph by Pedro Ribeiro Simões

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A Step in the Right Direction: Advancement in Robotics Leading to Better Prosthetics

3356514403_e378d11342New strides in robotics technology have made it possible to create new types of prosthetics, which can function more naturally than a passive artificial leg. The H. Fort Flowers Professor of Mechanical Engineering at Vanderbilt University, Michael Goldfarb and his colleagues at the Vanderbilt’s Center for Intelligent Mechatronics are the leaders in lower-limb prosthetic research and have expressed their views on robotic prosthetics in an article in Science Translational Medicine‘s November issue. Goldfarb’s team developed the first robotic prosthesis, which included a powered knee and ankle joints. Their design became the first artificial leg controlled by thought after researchers at the Rehabilitation Institute of Chicago added a neural interface to it.

Technological advances, such as lithium-ion batteries, powerful brushless electric motors with rare-Earth magnets, and miniaturized sensors built into semiconductor chips, have allowed for new developments in robotic prosthetics. The electric motors, whose batteries store a single charge with enough power to last a full day, serve as the “muscles” of the prosthetic. The sensors function as its “nerves” like those in the peripheral nervous system by providing information like the angle between the thigh and lower leg and the force exerted on the bottom of the foot. The microprocessor acts as the central nervous system by providing coordination.

In order to recognize a user’s intent to do different activities, there must be and effective control system that provides some type of connection with the central nervous system. There are many different methods available, but it is still undecided which of these is best. The least invasive approach uses physical sensors to differentiate between the user’s intentions and his or her body language. Electromyography interface is a different approach that places electrodes within the user’s leg muscles. The most invasive techniques entail electrode implants inside the user’s peripheral nerves or directly into his or her brain.

Bionic legs seem to provide many possible advantages over passive artificial legs. Lower-limb prostheses with a powered knee and heel joints have demonstrated faster walking speed and decreased hip effort while using less energy. Robotic prosthesis could also decrease the rate of falls leading to hospitalization due to the leg’s natural movement, improved compensation for uneven ground, and ability to help users recover from stumbling. Despite their benefits, robotic legs face some issues before being launched in the United States. These challenges include approval from the United States Food and Drug Administration (FDA) and additional robotics training for clinicians prescribing these types of prostheses.

In spite of these challenges, this new development of robotic legs will surely prove beneficial to amputees across the country. Is there a more efficient way to help the public gain access to this type of technology? What can be learned from these new advances?

Photograph by Andy Polaine

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Blue Morpho Butterfly Wings: More Than Just Pretty Faces

Morpho ButterflyThe beauty of butterflies, especially their wings, has captivated many a person. One butterfly, the Blue Morpho, has particularly stunning iridescent wings. Besides their beauty, these wings feature a unique characteristic, which could led to a variety of innovative technologies. Funded by the US Defense Advanced Research Projects Agency (DARPA), a team of researchers from the University of Exeter along with General Electric (GE) Global Research Center, University at Albany and Air Force Research Laboratory, has found the Morpho butterfly’s wings to include a physical structure and surface chemistry that provide amazing properties, which could present a diverse set of applications such as photonic security tags, self cleaning surfaces, protective clothing or industrial sensors. As noted in the journal PNAS, the study discovered that vapor molecules adhere differently to the top of the nanostructures on the scales of Morpho wings than to the bottom. A by-product of its wing scale development, this selectiveness to vapor molecules is what allows for the various bio-inspired technological applications described above. Dr. Radislav Potyrailo of GE and the Principal Investigator for this research program reported that this interdisciplinary team “unveil[ed] the existence of surface polarity gradient on the…butterfly scales,” which then allowed for the “multivariable perspective for vapor sensing, where selectivity is achieved with a single chemically graded nanostructured sensing unit, rather than from an array of separate sensors.”

In speaking about the iridescent properties of butterflies and moths and their relation to natural photonics, Professor Pete Vukusic of the University of Exeter said, “design ideas from nature [allow us] to work towards the development of applications in a range of different technologies.” I agree with this statement and believe it is important to not only come up with new technologies based on man-made ideas, but also from the natural phenomenons that already occur.

Do you know of any similar adaptions of natural properties? What are some of those naturally inspired technological (or other) innovations?

Photography credit: Ken Slade -

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