Catálogo de publicaciones - revistas

<jats:title>Dividing the Brain</jats:title> <jats:p> The cerebral cortex of the brain is organized into primary cortical areas, which receive direct inputs from the thalamus, and higher-order cortical areas, which in turn receive inputs from one or more primary cortical areas. <jats:bold> Chou <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6137" page="1239" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1232806">1239</jats:related-article> ) investigated the mechanisms underlying the specification of higher-order cortical areas. Input from the dorsal lateral geniculate nucleus into the primary visual area (V1) is required to drive the genetic and functional differentiation of a large visual cortical field into primary and higher-order visual areas. Thalamocortical axon input acts on a large visual cortical field. The afferents from the dorsal lateral geniculate are necessary to further refine the cortex into subareas that distinguish V1 from higher processing areas. In the relatively simple model that emerges from these findings, sensory input is essential to distinguish primary and higher-order cortical areas. </jats:p>

<jats:title>What Causes Obsessive Compulsive Disorder?</jats:title> <jats:p> Obsessive compulsive disorder is a severe, chronic mental illness that affects millions of individuals. However, the mechanisms underlying this disease are still largely unknown (see the Perspective by <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6137" page="1174" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1239652"> <jats:bold>Rauch and Carlezon Jr.</jats:bold> </jats:related-article> ). <jats:bold> Ahmari <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6137" page="1234" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1234733">1234</jats:related-article> ) stimulated glutamatergic pathways between the orbitofrontal cortex and the ventromedial striatum and used grooming to assess obsessive compulsive behavior in mice. Repetitive stimulation over days triggered changes in the neuronal responses of the ventromedial striatum. Over time, the behavior of the animals became independent of stimulation and could be prevented by the antidepressant fluoxetine. <jats:bold> Burguière <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6137" page="1243" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1232380">1243</jats:related-article> ) investigated the neural basis of obsessive compulsive symptoms in a mutant mouse that showed excessive expression of a conditioned form of grooming. </jats:p>

<jats:p>The discovery of green fluorescent protein a half century ago heralded a new and explosive era in microscopy, forever changing the landscape for biology imaging. The ability to fuse a genetically encoded fluorescent probe to an almost-unlimited variety of proteins has enabled scientists to investigate signaling pathways and the movement of intracellular proteins in living cells with unprecedented detail, particularly when coupled with powerful widefield fluorescence and confocal microscopy techniques. Today, using the expanded selection of probes now available, researchers can even monitor multiple proteins simultaneously, in real time. This webinar will investigate how fluorescent protein probes are currently being utilized for live cell imaging, with a focus on applications in cancer research and where newly developed probes might take us in the near future.</jats:p>

<jats:p>A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.</jats:p>

<jats:p>Listen to stories on Pacific hydrology, mini-guts in a dish, the mysteries of development, and more.</jats:p>

<jats:title>Holding Your Breath</jats:title><jats:p>Hemoglobin and myoglobin are widely responsible for oxygen transport and storage (see the Perspective by<jats:bold><jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6138" page="1293" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1240631">Rezende</jats:related-article></jats:bold>). The ability of diving mammals to obtain enough oxygen to support extended dives and foraging is largely dependent on muscle myoglobin (Mb) content.<jats:bold>Mirceta<jats:italic>et al.</jats:italic></jats:bold>(p.<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.sciencemag.org/content/340/6138/1234192.full">1234192</jats:ext-link>) found that in mammalian lineages with an aquatic or semiaquatic lifestyle, Mb net charge increases, which may represent an adaptation to inhibit self-association of Mb at high intracellular concentrations. Epistasis results from nonadditive genetic interactions and can affect phenotypic evolution.<jats:bold>Natarajan<jats:italic>et al.</jats:italic></jats:bold>(p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6138" page="1324" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1236862">1324</jats:related-article>) found that epistatic interactions were able to explain the increased hemoglobin oxygen-binding affinity observed in deer mice populations at high altitude. In mammals, the offloading of oxygen from hemoglobin is facilitated by a reduction in the blood's pH, driven by metabolically produced CO<jats:sub>2</jats:sub>. However, in fish, a reduction in blood pH reduces oxygen carrying capacity of hemoglobin.<jats:bold>Rummer<jats:italic>et al.</jats:italic></jats:bold>(p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6138" page="1327" related-article-type="in-this-issue" vol="340" xlink:href="10.1126/science.1233692">1327</jats:related-article>) implanted fiber optic oxygen sensors within the muscles of rainbow trout and found that elevated CO<jats:sub>2</jats:sub>levels in the water led to acidosis and elevated oxygen tensions.</jats:p>

<jats:p>In most people, language is processed predominantly by the left hemisphere of the brain, but we do not know how or why. A popular view is that developmental language disorders result from a poorly lateralized brain, but until recently, evidence has been weak and indirect. Modern neuroimaging methods have made it possible to study normal and abnormal development of lateralized function in the developing brain and have confirmed links with language and literacy impairments. However, there is little evidence that weak cerebral lateralization has common genetic origins with language and literacy impairments. Our understanding of the association between atypical language lateralization and developmental disorders may benefit if we reconceptualize the nature of cerebral asymmetry to recognize its multidimensionality and consider variation in lateralization over developmental time. Contrary to popular belief, cerebral lateralization may not be a highly heritable, stable characteristic of individuals; rather, weak lateralization may be a consequence of impaired language learning.</jats:p>