Bilateral olfactory sensory input enhances chemotaxis behavior.

Neural comparisons of bilateral sensory inputs are essential for visual depth perception and accurate localization of sounds in space. All animals, from single-cell prokaryotes to humans, orient themselves in response to environmental chemical stimuli, but the contribution of spatial integration of neural activity in olfaction remains unclear. We investigated this problem in Drosophila melanogaster larvae. Using high-resolution behavioral analysis, we studied the chemotaxis behavior of larvae with a single functional olfactory neuron on either the left or right side of the head, allowing us to examine unilateral or bilateral olfactory input. We developed new spectroscopic methods to create stable odorant gradients in which odor concentrations were experimentally measured. In these controlled environments, we observed that a single functional neuron provided sufficient information to permit larval chemotaxis. We found additional evidence that the overall accuracy of navigation is enhanced by the increase in the signal-to-noise ratio conferred by bilateral sensory input.

Prepupal Building Behavior in Drosophila melanogaster and Its Evolution under Resource and Time Constraints.

Structures built by animals are a widespread and ecologically important 'extended phenotype'. While its taxonomic diversity has been well described, factors affecting short-term evolution of building behavior within a species have received little experimental attention. Here we describe how, given the opportunity, wandering Drosophila melanogaster larvae often build long tunnels in agar substrates and embed their pupae within them. These embedded larvae are characterized by a longer egg-to-pupariation developmental time than larvae that pupate on the surface. Assuming that such building behaviors are likely to be energetically costly and/or time consuming, we hypothesized that they should evolve to be less pronounced under resource or time limitation. In accord with this prediction, larvae from populations evolved for 160 generations under a regime that combines larval malnutrition with limited developmental time dug shorter tunnels than larvae from control unselected populations. However, the proportion of larvae that embedded before pupation did not differ between the malnutrition-adapted and control populations, suggesting that tunnel length and likelihood of embedding before pupation are controlled by different genetic loci. The behaviors exhibited by wandering larvae of Drosophila melanogaster prior to pupation offer a model system to study evolution of animal building behaviors because the tunneling and embedding phenotypes are simple, facultative and highly variable.

La dépendance à l'égard de l'environnement lors de lésions cérébrales: conduites d'imitation, de préhension et d'utilisation [Environmental dependence in brain lesions: imitative behavior, prehension and utilization].

This paper reviews the literature on clinical signs such as imitation behavior, grasp reaction, manipulation of tools, utilization behavior, environmental dependency, hyperlexia, hypergraphia and echolalia. Some aspects of this semiology are of special interest because they refer to essential notions such as free-will and autonomy.

Occurrences of flesh flies (Diptera: Sarcophagidae) on human cadavers in Switzerland, and their importance as forensic indicators.

From 1993 to 2008, criminal investigations were conducted in the western part of Switzerland with special attention to blowfly and flesh fly species in order to estimate the post-mortem interval when requested by the police authorities. Flesh flies were found in only 33 cases out of 160. Five species of the genus Sarcophaga were identified (S. africa, S. argyrostoma, S. caerulescens, S. similis and S. sp.). The main species found on corpses (larval stage) was S. argyrostoma. The thermal constant (K) calculated for this species in Switzerland is 380.6 ± 16.3 (mean ± S.D.) degree-days. With the exception of S. caerulescens, found three times in the larval stage on corpses, the three other species are of minor forensic importance. S. argyrostoma is found during summer and indoors. This species colonises dead bodies, usually the same day as blowfly species, and it could be used to estimate the post-mortem interval. Other species are discussed in the light of current knowledge on their biology and ecology. It is recommended that voucher material be deposited in a museum, allowing further studies by relevant specialists, thereby helping investigators and avoiding misidentifications.

Molecular variation at a candidate gene implicated in the regulation of fire ant social behavior

The fire ant Solenopsis invicta and its close relatives display an important social polymorphism involving differences in colony queen number. Colonies are headed by either a single reproductive queen (monogyne form) or multiple queens (polygyne form). This variation in social organization is associated with variation at the gene Gp-9, with monogyne colonies harboring only B-like allelic variants and polygyne colonies always containing b-like variants as well. We describe naturally occurring variation at Gp-9 in fire ants based on 185 full-length sequences, 136 of which were obtained from S. invicta collected over much of its native range. While there is little overall differentiation between most of the numerous alleles observed, a surprising amount is found in the coding regions of the gene, with such substitutions usually causing amino acid replacements. This elevated coding-region variation may result from a lack of negative selection acting to constrain amino acid replacements over much of the protein, different mutation rates or biases in coding and non-coding sequences, negative selection acting with greater strength on non-coding than coding regions, and/or positive selection acting on the protein. Formal selection analyses provide evidence that the latter force played an important role in the basal b-like lineages coincident with the emergence of polygyny. While our data set reveals considerable paraphyly and polyphyly of S. invicta sequences with respect to those of other fire ant species, the b-like alleles of the socially polymorphic species are monophyletic. An expanded analysis of colonies containing alleles of this clade confirmed the invariant link between their presence and expression of polygyny. Finally, our discovery of several unique alleles bearing various combinations of b-like and B-like codons allows us to conclude that no single b-like residue is completely predictive of polygyne behavior and, thus, potentially causally involved in its expression. Rather, all three typical b-like residues appear to be necessary.

Behavior of endogenous tumor-associated macrophages assessed in vivo using a functionalized nanoparticle.

Tumor-associated macrophages (TAMs) invade the tumor stroma in many cancers, yet their role is incompletely understood. To visualize and better understand these critical cells in tumor progression, we screened a portfolio of rationally selected, injectable agents to image endogenous TAMs ubiquitously in three different cancer models (colon carcinoma, lung adenocarcinoma, and soft tissue sarcoma). AMTA680, a functionally derivatized magneto-fluorescent nanoparticle, labeled a subset of myeloid cells with an "M2" macrophage phenotype, whereas other neighboring cells, including tumor cells and a variety of other leukocytes, remained unlabeled. We further show that AMTA680-labeled endogenous TAMs are not altered and can be tracked noninvasively at different resolutions and using various imaging modalities, e.g., fluorescence molecular tomography, magnetic resonance imaging, and multiphoton and confocal intravital microscopy. Quantitative assessment of TAM distribution and activity in vivo identified that these cells cluster in delimited foci within tumors, show relatively low motility, and extend cytoplasmic protrusions for prolonged physical interactions with neighboring tumor cells. Noninvasive imaging can also be used to monitor TAM-depleting regimen quantitatively. Thus, AMTA680 or related cell-targeting agents represent appropriate injectable vehicles for in vivo analysis of the tumor microenvironment.

Emotional behavior in acute stroke: the Lausanne emotion in stroke study.

OBJECTIVE: To study emotional behaviors in an acute stroke population. BACKGROUND: Alterations in emotional behavior after stroke have been recently recognized, but little attention has been paid to these changes in the very acute phase of stroke. METHODS: Adult patients presenting with acute stroke were prospectively recruited and studied. We validated the Emotional Behavior Index (EBI), a 38-item scale designed to evaluate behavioral aspects of sadness, aggressiveness, disinhibition, adaptation, passivity, indifference, and denial. Clinical, historical, and imaging (computed tomography/magnetic resonance imaging) data were obtained on each subject through our Stroke Registry. Statistical analysis was performed with both univariate and multivariate tests. RESULTS: Of the 254 patients, 40% showed sadness, 49% passivity, 17% aggressiveness, 53% indifference, 76% disinhibition, 18% lack of adaptation, and 44% denial reactions. Several significant correlations were identified. Sadness was correlated with a personal history of alcohol abuse (r = P < 0.037), female gender (r = P < 0.028), and hemorrhagic nature of the stroke (r = P < 0.063). Aggressiveness was correlated with a personal history of depression (r = P < 0.046) and hemorrhage (r = P < 0.06). Denial was correlated with male gender (r = P < 0.035) and hemorrhagic lesions (r = P < 0.05). Emotional behavior did not correlate with either neurologic impairment or lesion localization, but there was an association between hemorrhage and aggressive behavior (P < 0.001), lack of adaptation (r = P < 0.015), indifference (r = P < 0.018), and denial (r = P < 0.045). CONCLUSIONS: Systematic observations of acute emotional behaviors after stroke suggest that emotional alterations are independent of mood and physical status and should be considered as a separate consequence of stroke.

Catastrophic reaction in acute stroke: a reflex behavior in aphasic patients.

Twelve patients with a catastrophic reaction (CR) (an outburst of frustration, depression, and anger when confronted with a task) were identified in a prospective cohort population (n = 326) with first-ever stroke admitted within 48 hours from onset. The authors' findings suggest that CR is a rare though not exceptional phenomenon in acute stroke and is associated with nonfluent aphasias and left opercular lesions. CR, poststroke depression, and emotionalism are distinct but related disorders.

Neither Bad Apple nor Bad Barrel: How the Societal Context Impacts Unethical Behavior in Organizations

Every time another corporate scandal captures media headlines, the 'bad apple vs. bad barrel' discussion starts anew. Yet this debate overlooks the influence of the broader societal context on organizational behavior. In this article, we argue that misbehaviors of organizations (the 'barrels') and their members (the 'apples') cannot be addressed properly without a clear understanding of their broader context (the 'larder'). Whereas previously, a strong societal framework dampened the practical application of the Homo economicus concept (business actors as perfectly rational and egocentric utility-maximizing agents without any moral concern), specialization, individualization and globalization led to a business world disembedded from broader societal norms. This emancipated business world promotes a literal interpretation of Homo economicus among business organizations and their members. Consequently, we argue that the first step toward 'healthier' apples and barrels is to sanitize the larder, that is, adapt the framework in which organizations and their members evolve.Chaque fois qu'un nouveau scandale fait la une des médias, la question de savoir si le problème se situe au niveau des individus (des 'pommes isolées') ou au niveau des organisations (les 'caisses de pommes') refait surface. Ce débat tend néanmoins à sous-estimer l'influence du contexte sociétal plus large sur le comportement dans les organisations. Dans cet article, nous soutenons l'idée que les scandales éthiques dans les organisations ou parmi leurs membres ne peuvent être compris correctement sans une vision plus précise de leur contexte plus large (la 'cave à pommes'). Si dans le passé un contexte sociétal fort permettait d'adoucir les applications pratiques de l'Homo economicus (qui considère l'acteur économique comme un agent parfaitement rationnel et égocentrique cherchant à maximiser son utilité sans réflexion morale), l'individualisation et la globalisation ont conduit à un monde économique désencastré et déconnecté des normes sociales plus larges. Ce monde économique autonome promouvoit une interprétation littérale de l'Homo economicus parmi les entreprises et leurs employés. Il en résulte que le premier pas vers des pommes moins pourries passe par un assainissement de la cave, c'est-à-dire l'adoption d'un cadre socio-normatif qui permet un recadrage du contexte dans lequel les organisations économiques et leurs acteurs agissent.

A dynamic assessment of medication-taking behavior during pregnancy and postpartum: should cART adherence be reinforced during postpartum?

This study compared adherence (persistence and execution) during pregnancy and postpartum in HIV-positive women having taken part in the adherence-enhancing program of the Community Pharmacy of the Department of Ambulatory Care and Community Medicine in Lausanne between 2004 and 2012. This interdisciplinary program combined electronic drug monitoring and semi-structured, repeated motivational interviews. This was a retrospective, observational study. Observation period spread over from first adherence visit after last menstruation until 6 months after childbirth. Medication-taking was recorded by electronic drug monitoring. Socio-demographic and delivery data were collected from Swiss HIV Cohort database. Adherence data, barriers and facilitators were collected from pharmacy database. Electronic data were reconciled with pill-count and interview notes in order to include reported pocket-doses. Execution was analyzed over 3-day periods by a mixed effect logistic model, separating time before and after childbirth. This model allowed us to estimate different time slopes for both periods and to show a sudden fall associated with childbirth. Twenty-five pregnant women were included. Median age was 29 (IQR: 26.5, 32.0), women were in majority black (n_17,68%) and took a cART combining protease and nucleoside reverse transcriptase inhibitors (n_24,96%). Eleven women (44%) were ART-naı¨ve at the beginning of pregnancy. Twenty women (80%) were included in the program because of pregnancy. Women were included at all stages of pregnancy. Six women (24%) stopped the program during pregnancy, 3 (12%) at delivery, 4 (16%) during postpartum and 12 (48%) stayed in program at the end of observation time. Median number of visits was 4 (3.0, 6.3) during pregnancy and 3 (0.8, 6.0) during postpartum. Execution was continuously high during pregnancy, low at beginning of postpartum and increased gradually during the 6 months of postpartum. Major barriers to adherence were medication adverse events and difficulties in daily routine. Facilitators were motivation for promoting child-health and social support. The dramatic drop and very slow increase in cART adherence during postpartum might result in viral rebound and drug resistance. Although much attention is devoted to pregnant women, interdisciplinary care should also be provided to women in the community during first trimester of postpartum to support them in sustaining cART adherence.

Evolutionary ecology of learning: insights from fruit flies

Ecologically and evolutionarily oriented research on learning has traditionally been carried out on vertebrates and bees. While less sophisticated than those animals, fruit flies (Drosophila) are capable of several forms of learning, and have an advantage of a short generation time, which makes them an ideal system for experimental evolution studies. This review summarizes the insights into evolutionary questions about learning gained in the last decade from evolutionary experiments on Drosophila. These experiments demonstrate that Drosophila have the genetic potential to evolve substantially improved learning performance in ecologically relevant learning tasks. In at least one set of selected populations the improved learning generalized to another task than that used to impose selection, involving a different behavior, different stimuli, and a different sensory channel for the aversive reinforcement. This improvement in learning ability was associated with reduction in other fitness-related traits, such as larval competitive ability and lifespan, pointing out to evolutionary trade-offs of improved learning. These trade-offs were confirmed by other evolutionary experiments where reduction in learning performance was observed as a correlated response to selection for tolerance to larval nutritional stress or for delayed aging. Such trade-offs could be one reason why fruit flies have not fully used up their evolutionary potential for learning ability. Finally, another evolutionary experiment with Drosophila provided the first direct evidence for the long-standing ideas that learning can under some circumstances accelerate and in other slow down genetically-based evolutionary change. These results demonstrate the usefulness of fruit flies as a model system to address evolutionary questions about learning.