Holidays slightly altered the publication dates at PLoS this week, so I had to wait until Wednesday to bring you my picks from PLoS Biology, PLoS Medicine and PLoS ONE. Of course, look beyond my own picks and look at all the new articles to see what you are interested in:
Recurring Ethanol Exposure Induces Disinhibited Courtship in Drosophila:
Alcohol has a strong causal relationship with sexual arousal and disinhibited sexual behavior in humans; however, the physiological support for this notion is largely lacking and thus a suitable animal model to address this issue is instrumental. We investigated the effect of ethanol on sexual behavior in Drosophila. Wild-type males typically court females but not males; however, upon daily administration of ethanol, they exhibited active intermale courtship, which represents a novel type of behavioral disinhibition. The ethanol-treated males also developed behavioral sensitization, a form of plasticity associated with addiction, since their intermale courtship activity was progressively increased with additional ethanol experience. We identified three components crucial for the ethanol-induced courtship disinhibition: the transcription factor regulating male sex behavior Fruitless, the ABC guanine/tryptophan transporter White and the neuromodulator dopamine. fruitless mutant males normally display conspicuous intermale courtship; however, their courtship activity was not enhanced under ethanol. Likewise, white males showed negligible ethanol-induced intermale courtship, which was not only reinstated but also augmented by transgenic White expression. Moreover, inhibition of dopamine neurotransmission during ethanol exposure dramatically decreased ethanol-induced intermale courtship. Chronic ethanol exposure also affected a male’s sexual behavior toward females: it enhanced sexual arousal but reduced sexual performance. These findings provide novel insights into the physiological effects of ethanol on sexual behavior and behavioral plasticity.
Previous studies have succeeded in identifying the cognitive state corresponding to the perception of a set of depicted categories, such as tools, by analyzing the accompanying pattern of brain activity, measured with fMRI. The current research focused on identifying the cognitive state associated with a 4s viewing of an individual line drawing (1 of 10 familiar objects, 5 tools and 5 dwellings, such as a hammer or a castle). Here we demonstrate the ability to reliably (1) identify which of the 10 drawings a participant was viewing, based on that participant’s characteristic whole-brain neural activation patterns, excluding visual areas; (2) identify the category of the object with even higher accuracy, based on that participant’s activation; and (3) identify, for the first time, both individual objects and the category of the object the participant was viewing, based only on other participants’ activation patterns. The voxels important for category identification were located similarly across participants, and distributed throughout the cortex, focused in ventral temporal perceptual areas but also including more frontal association areas (and somewhat left-lateralized). These findings indicate the presence of stable, distributed, communal, and identifiable neural states corresponding to object concepts.
Over the past decade, workers in physics education research have developed effective instructional methods and materials (e.g., workshop physics ; lecture demonstrations ; tutorials in introductory physics ) based on research into student thinking. A Socratic process of questioning and careful analysis of responses can reveal students’ thinking on a subject area, including misconceptions, prior conceptions, and conceptual lacunae. Applying this approach to biological concepts, we have built a software system, called Ed’s Tools, to capture and analyze student responses. Both instructors and researchers can use this system to obtain a more complete and nuanced picture of student understanding, which can then serve as the foundation on which to base subsequent instruction and the construction of concept inventories. We illustrate the value of the data obtained through this analysis by showing how it helped us trace the conceptual problems that students have in two subject areas, molecular biology and evolutionary biology, to a common cause: a fundamental misunderstanding of random processes.
Background to the debate: Systematic reviews that combine high-quality evidence from several trials are now widely considered to be at the top of the hierarchy of clinical evidence. Given the primacy of systematic reviews–and the fact that individual clinical trials rarely provide definitive answers to a clinical research question–some commentators question whether the sample size calculation for an individual trial still matters. Others point out that small trials can still be potentially misleading.