The neural circuits controlling feeding and emotional behaviors are intricately and reciprocally connected. Recent technological developments, including cell type-specific optogenetic and ...chemogenetic approaches, allow functional characterization of genetically defined cell populations and neural circuits in feeding and emotional processes. Here we review recent studies that have utilized circuit-based manipulations to decipher the functional interactions between neural circuits controlling feeding and those controlling emotional processes. Specifically, we highlight newly described neural circuit interactions between classical emotion-related brain regions, such as the hippocampus and amygdala, and homeostatic feeding circuitry in the arcuate nucleus and lateral hypothalamus (LH). Together these circuits will provide a template for future studies to examine functional interactions between feeding and emotion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Nonrandom collecting practices may bias conclusions drawn from analyses of herbarium records. Recent efforts to fully digitize and mobilize regional floras online offer a timely opportunity to assess ...commonalities and differences in herbarium sampling biases.
We determined spatial, temporal, trait, phylogenetic, and collector biases in c. 5 million herbarium records, representing three of the most complete digitized floras of the world: Australia (AU), South Africa (SA), and New England, USA (NE).
We identified numerous shared and unique biases among these regions. Shared biases included specimens collected close to roads and herbaria; specimens collected more frequently during biological spring and summer; specimens of threatened species collected less frequently; and specimens of close relatives collected in similar numbers. Regional differences included overrepresentation of graminoids in SA and AU and of annuals in AU; and peak collection during the 1910s in NE, 1980s in SA, and 1990s in AU. Finally, in all regions, a disproportionately large percentage of specimens were collected by very few individuals. We hypothesize that these mega-collectors, with their associated preferences and idiosyncrasies, shaped patterns of collection bias via ‘founder effects’.
Studies using herbarium collections should account for sampling biases, and future collecting efforts should avoid compounding these biases to the extent possible.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
It is well recognized that ventromedial hypothalamus (VMH) serves as a satiety center in the brain. However, the feeding circuit for the VMH regulation of food intake remains to be defined. Here, we ...combine fiber photometry, chemo/optogenetics, virus-assisted retrograde tracing, ChR2-assisted circuit mapping and behavioral assays to show that selective activation of VMH neurons expressing steroidogenic factor 1 (SF1) rapidly inhibits food intake, VMH SF1 neurons project dense fibers to the paraventricular thalamus (PVT), selective chemo/optogenetic stimulation of the PVT-projecting SF1 neurons or their projections to the PVT inhibits food intake, and chemical genetic inactivation of PVT neurons diminishes SF1 neural inhibition of feeding. We also find that activation of SF1 neurons or their projections to the PVT elicits a flavor aversive effect, and selective optogenetic stimulation of ChR2-expressing SF1 projections to the PVT elicits direct excitatory postsynaptic currents. Together, our data reveal a neural circuit from VMH to PVT that inhibits food intake.
Mentoring is important to the development and enhancement of the medical profession and to organizational performance. The challenge is to implement a mentoring program within your organization. ...Leaders can use this article to assist in training both mentors and mentees. This article reminds people that the mindsets and skills necessary to become good mentor and mentee improve with practice, thus engage, learn, and improve. The time invested in mentoring relationships enhances patient care, creates positive work environment within organizations, improves individual and organizational performance, and creates a brighter future for the medical profession.
Emerging evidence shows that hypothalamic astrocytes react to and counteract energy surfeit produced by high‐fat diet (HFD) feeding. However, the functional role of astrocytes in the control of ...energy states and the underlying molecular mechanism(s) during physiological conditions remain largely underexplored. In the present study, by taking advantage of spatiotemporally precise optogenetic approaches, real‐time measurements of extracellular adenosine, and behavioral assays, we find that optogenetic stimulation of astrocytes localized in the medial basal hypothalamus (MBH) suppresses food intake in a frequency dependent manner with high frequency, but not low frequency, stimulation of astrocytes reducing food intake. Furthermore, stimulation of MBH astrocytes diminishes orexigenic ghrelin or fasting‐induced hyperphagia without effecting anxiety‐related behavior. Consistent with a frequency dependent role for MBH astrocytes in feeding behavior, optogenetic stimulation of MBH astrocytes increases extracellular levels of adenosine in a frequency dependent manner. Collectively, our results provide new insights into the role of astrocytes in physiological functions during naturally occurring behaviors, such as feeding. GLIA 2016;64:2263–2273
Main Points
Activity‐dependent adenosine‐mediated suppression of food intake.
Activity‐dependent astrocytic elevation of extracellular adenosine.
Activation of astrocytes did not effect anxiety‐related behaviors.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Leaders, particularly new leaders, seek to establish high levels of trust, as it has been associated with higher levels of effectiveness and group outcomes. This study is designed to understand how ...trust changes and develops for leaders in a new role and the implications of that change. Although calls for research on trust over time have been made for the past 2 decades, our knowledge of this phenomenon is still quite limited. The findings indicate that leader and unit performance is a function not only of absolute trust level, but is also affected by the direction and magnitude of change in trust across time periods, with the highest levels of effectiveness being associated with leaders who exhibited an increase in trust from the group over time. The data also suggest that the direction and rate at which trust grew was determined by initial expectations and transformational leadership behaviors.
In a recent publication dealing with the sectional-level taxonomy of Garcinia , an illegitimate superfluous sectional name and two illegitimate homonyms were published. Herein we choose a legitimate ...sectional name, Garcinia section Rheediopsis Pierre, for the superfluous name Garcinia section Rheedia (L.) S.W.Jones ex P.W.Sweeney; and create two new legitimate names in Garcinia for Allanblackia gabonensis (Pellegr.) Bamps and A. parviflora A.Chev.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We used a near-complete phylogeny for the angiosperm clade Viburnum to assess lineage diversification rates, and to examine possible morphological and ecological factors driving radiations.
...Maximum-likelihood and Bayesian approaches identified shifts in diversification rate and possible links to character evolution. We inferred the ancestral environment for Viburnum and changes in diversification dynamics associated with subsequent biome shifts.
Viburnum probably diversified in tropical forests of Southeast Asia in the Eocene, with three subsequent radiations in temperate clades during the Miocene. Four traits (purple fruits, extrafloral nectaries, bud scales and toothed leaves) were statistically associated with higher rates of diversification. However, we argue that these traits are unlikely to be driving diversification directly. Instead, two radiations were associated with the occupation of mountainous regions and a third with repeated shifts between colder and warmer temperate forests.
Early-branching depauperate lineages imply that the rare lowland tropical species are ‘dying embers’ of once more diverse lineages; net diversification rates in Viburnum likely decreased in these tropical environments after the Oligocene. We suggest that ‘taxon pulse’ dynamics might characterize other temperate plant lineages.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Species are the starting point for most studies of ecology and evolution, but the proper circumscription of species can be extremely difficult in morphologically variable lineages, and there are ...still few convincing examples of molecularly informed species delimitation in plants. Here, we focus on the Viburnum nudum complex, a highly variable clade that is widely distributed in eastern North America. Taxonomic treatments have mostly divided this complex into northern (V. nudum var. cassinoides) and southern (V. nudum var. nudum) entities, but additional names have been proposed. We used multiple lines of evidence, including RADseq, morphological, and geographic data, to test how many independently evolving lineages exist within the V. nudum complex. Genetic clustering and phylogenetic methods revealed three distinct groups—one lineage that is highly divergent, and two others that are recently diverged and morphologically similar. A combination of evidence that includes reciprocal monophyly, lack of introgression, and discrete rather than continuous patterns of variation supports the recognition of all three lineages as separate species. These results identify a surprising case of cryptic diversity in which two broadly sympatric species have consistently been lumped in taxonomic treatments. The clarity of our findings is directly related to the dense sampling and high-quality genetic data in this study. We argue that there is a critical need for carefully sampled and integrative species delimitation studies to clarify species boundaries even in well-known plant lineages. Studies following the model that we have developed here are likely to identify many more cryptic lineages and will fundamentally improve our understanding of plant speciation and patterns of species richness.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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