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The #NobelPrize in #Physiology or #Medicine has been awarded to John O’Keefe and Edvard I. & May-Britt Moser for their beautiful work on the physiological underpinnings of the navigation system of the #mammalian brain. In 1976, O’Keefe published this paper showing how some #neurons in #rat #hippocampus are selectively active when the animal is in specific parts of an enclosed environment. For example, in the image below, the hatched area labelled “202-1” (toward the bottom left) is that in which one of these so-called #PlaceCells (cell 202-1) became selectively excited (it was not active when the rat was in other parts of the #maze). This discovery set of a wave of research that led to fundamental breakthroughs in our understandings of navigation and memory. One question raised by O’Keefe’s findings is: what information is used by place cells to define the spatial boundaries of their “place fields”? This question was answered by the #Mosers in 2005 (explained in my next post). #Science #Neuroscience #SystemsNeuroscience #Electrophysiology #ExpNeurol DOI: 10.1016/0014-4886(76)90055-8

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#Melatonin is that stuff you take to help you sleep when you don’t have the good stuff because your mom has some in her medicine cabinet (aka a #neurohormone that regulates sleep and seasonal behavior in vertebrates). However, nearly all forms of life possess this antioxidant #molecule, and it functions to protect cells from oxidative animals across the board. Note that its protective function being so ubiquitous strongly implies that this is its evolutionarily oldest use. So how did a simple protective absorber of harmful stuff end up in a complex signalling cascade regulating sleep? The authors of a recent study have found a heretofore unrecognized role for melatonin that suggests an evolutionary linkage between its function in invertebrates, and its job regulating sleep in vertebrates. Specifically, they found that melatonin regulates something called “diel vertical migration (DVM)”, in which most invertebrates and some fish rise to the surface of lakes and oceans during the night and sink to the depths during the day. Even more specifically, it appears that melatonin’s job is to essentially to turn off the neurons that control “ciliary swimming”, thus its effect on day/night swimming. This is a far “simpler” mechanism than that exhibited by melatonin in regulating our own day/night cycle of behaviors, but far more complex than a being a cellular janitor, thus the intriguing speculation that the mechanism represents an evolutionary stepping stone. #science #evolution #cell 10.1016/j.cell.2014.09.004

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Are you a “pre-crastinator?” A recent study suggests that there may be a bias towards completing simple tasks sooner than is strictly necessary in order to avoid having to remember to do them later. In this series of experiments, subjects were asked to choose one of two buckets to carry to the end of a corridor (see inset schematic-layout). The experimenters varied the relative distance of the two buckets from their destination: sometimes the two were equally far, but more often one was closer to the end than the other. Intuitively, one might expect that people would opt to carry the bucket a shorter distance, meaning they’d select the bucket closer to the end, farther from themselves. However, what the graph below shows is that people were generally biased towards picking a bucket that was closer to them along the corridor, and farther from the end. The graph indicates the probability of selecting the right-hand bucket as a function of the relative distances of both buckets; to the left of the vertical dashed line, the left-hand bucket is closer to the subject’s starting position (and farther from the end of the corridor), and to the right of the dashed line the right-hand bucket is closer. One way of looking at this data is to focus on the data points to the right of the dashed line: there we can see that despite the left-hand bucket being nearer to the end of the corridor, subjects chose the right-hand bucket more than 50% of the time (horizontal dashed line), requiring them to carry the bucket further on average. Thus, people in this study tend to work a bit harder, just to get the job of making a choice out of the way a bit sooner. #science #psychology #precrastination http://pss.sagepub.com/content/25/7/1487

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Sleeping in a cold room (19 Celsius / 66 Fahrenheit) can increase #metabolism and #insulin sensitivity. Researchers had volunteers sleep and eat in a controlled environment for 4 months. In each months, the ambient temperature of their sleeping quarters was kept constant. The sequence of temperatures was: 24C-19C-24C-27C. Seeping in the 19C room had the effects described above, which were abolished by sleeping in the 24C room. #Science #Diabetes http://diabetes.diabetesjournals.org/content/early/2014/06/18/db14-0513

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Is it better to be from a family with many children or few? Which results in more successful kids? Does it matter if the family is well off? What about long-term effects: do children from big families have more children than those from small? Perhaps children in small wealthy families eventually produce the biggest broods? These questions, regarding the interactions of family size, socioeconomic position (SEP), individual success and reproductive success are complex and fascinating grist for the imagination mill. This study of 14,000 Swedes and their descendents has found that family size among high "SEP" individuals is a strong predictor of descendent SEP: smaller families result in higher SEP descendents. Not so among low SEP families. The graph shows one of many variables (probability of entering university) which track SEP in descendants.However, the interaction between family size and SEP had no effect on reproductive success! Regardless of origin (high/low SEP x large/small family), average number of descendents was the same.#Science #rspb

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Chronic exposure to UV light, which causes #tanning, may be addictive. Such exposure causes the production of beta-opioid, which provides analgesic (pain killing) relief. However, opioids are addictive, and as this study shows, chronically UV exposed mice showed clear symptoms of withdrawal after the UV application was stopped. #science #cell http://www.sciencedirect.com/science/article/pii/S0092867414006114

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#FireAnts #SelfAssemble into structures such as: (A) rafts, (B) hanging columns, (C) bivouacs, (D) escape droplets and (E) towers (upper left). The dedicated authors of this work used #ElectronMicroscopy, micro-CAT scanning, and modeling to figure out just what it takes to achieve these cooperative living architectures.#science #animalbehavior #jeb http://jeb.biologists.org/content/217/12/2089.full

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This is an entire #Zebrafish #brain. Every #neuron is being imaged simultaneously while the animal is responding to the presentation of various directions of motion (inset arrows). The fish tries to align his swimming body so that the motion is flowing under him from head-to-tail. The colors of the neurons indicate their preference for motion direction. This beautiful "chemistry of stars" was presented by #JeremyFreeman back in May at #VSS2014, he works at #JaneliaFarms on a variety of cool projects. #science #neuroscience #CalciumImaging via http://www.jeremyfreeman.net