A right antenna for social behaviour in honeybees

Sophisticated cognitive abilities have been documented in honeybees, possibly an aspect of their complex sociality. In vertebrates brain asymmetry enhances cognition and directional biases of brain function are a putative adaptation to social behaviour. Here we show that honeybees display a strong lateral preference to use their right antenna in social interactions. Dyads of bees tested using only their right antennae (RA) contacted after shorter latency and were significantly more likely to interact positively (proboscis extension) than were dyads of bees using only their left antennae (LA). The latter were more likely to interact negatively (C-responses) even though they were from the same hive. In dyads from different hives C-responses were higher in RA than LA dyads. Hence, RA controls social behaviour appropriate to context. Therefore, in invertebrates, as well as vertebrates, lateral biases in behaviour appear to be associated with requirements of social life

In-vivo two-photon imaging of the honey bee antennal lobe

Due to the honey bee's importance as a simple neural model, there is a great need for new functional imaging modalities. Herein we report on the use of two-photon microscopy for in-vivo functional and morphological imaging of the honey bee's olfactory system focusing on its primary centers, the antennal lobes (ALs). Our imaging platform allows for simultaneously obtaining both morphological measurements of the AL and in-vivo calcium recording of neural activities. By applying external odor stimuli to the bee's antennas, we were able to record the characteristic odor response maps. Compared to previous works where conventional fluorescence microscopy is used, our approach offers all the typical advantages of multi-photon imaging, providing substantial enhancement in both spatial and temporal resolutions while minimizing photo-damages and autofluorescence contribution with a four-fold improvement in the functional signal. Moreover, the multi-photon associated extended penetration depth allows for functional imaging within profound glomeruli.Comment: 3 pages, 3 figure

Side differences during odour processing in the honey bee brain

Trabalho de projecto de mestrado em Medicina (Pneumologia), apresentado à Faculdade de Medicina da Universidade de CoimbraA pneumonia adquirida na comunidade (PAC) é uma doença que revela morbilidade e mortalidade significativas. Os doentes mais graves necessitam de hospitalização e por vezes reúnem critérios de gravidade que condicionam o seu internamento na unidade de cuidados intensivos (UCI), constituindo uma das entidades mais frequentes nestes serviços. Apesar de controverso, o termo “severa” é frequentemente atribuído à doença que requer internamento na UCI, constituindo a definição mais comum. Pelos recursos exigidos com o internamento quer ao nível da enfermaria, quer na UCI, reconhece-se como uma entidade com impacto socioeconómico significativo, daí a importância de escalonar correctamente os doentes que reúnem critérios de severidade e que necessitam de internamento. Objectivo do trabalho Propõe-se a realização de uma revisão da literatura que permita elucidar à luz dos conhecimentos actuais diversos aspectos relativos a esta entidade, designadamente clarificar a sua definição, caracterizando aspectos particulares da sua prevalência e história natural, e congregar diferentes directivas já existentes visando definir claramente o grau de severidade, o que determinará um melhor prognóstico e rentabilização de recursos pela instituição precoce da terapêutica adequada. Pretende-se ainda um esclarecimento quanto à identificação sistematizada dos doentes que reúnem critérios para admissão em UCI bem como quanto às implicações em termos de prognóstico resultante da condição de severidade. Desenvolvimento Para definir a PAC severa (PACS) há que atender a parâmetros que incluem a fisiopatogenia, os factores risco/co-morbilidades associados e o processo diagnóstico em termos clínicos, PAC Severa: Definição, Particularidades e Factores Preditivos para Admissão em Unidade de Cuidados Intensivos R Ferreira, S Freitas 3 laboratoriais (diagnóstico etiológico) e imagiológicos. Desenvolveram-se vários scores/índices de gravidade para escalonar apropriadamente os doentes que requerem internamento. A sua aplicação estratifica a severidade e prediz o prognóstico. Vários factores estão implicados no prognóstico, nomeadamente a maior duração do internamento ou um timing de admissão mais tardio. Avaliou-se igualmente a utilidade prognóstica de biomarcadores como a pró-calcitonina, proteína C reactiva, algumas interleucinas e o cortisol plasmático, bem como o status socioeconómico, variabilidade genética, toma de anti-inflamatórios não esteróides, ventilação mecânica e o seguimento das guidelines. Conclusões A definição mais consensual de PACS continua a ser a que implica internamento em UCI, apresentando-se o Streptococcus pneumoniae como o agente etiológico mais frequente. Dos diversos scores de gravidade disponíveis, as directivas IDSA/ATS 2007 revelaram-se como as mais equilibradas, pelo que a sua aplicação se traduziu num impacto prognóstico positivo significativo. Em termos futuros, prevê-se que o desenvolvimento da investigação na área dos biomarcadores inflamatórios poderá incrementar a acuidade diagnóstica e prognóstica nesta patologiaThe community-acquired pneumonia (CAP) is a disease responsible for significant morbidity and mortality. The most critical patients require hospitalization and sometimes meet severity criteria that determine their admission in the intensive care unit (ICU), being one of the most common situations in these services. Although controversial, the term "severe" is often attributed to the disease that requires admission to ICU, being the most common definition. Given the amount of resources it requires, not only in the ward but also in the ICU, the CAP is recognized as an entity with significant economic impact, hence the importance of properly scaling the patients who meet the criteria for severe CAP and require hospitalization. This article seeks to review the literature to clarify the current knowledge over several aspects of this entity, including its definition, its prevalence and natural history, and to sum up various existing directives in order to clearly define the degree of severity, which determines the prognosis and allows a faster appropriate response as well as a better resources management. This review also aims at establishing a method of identifying the patients that meet the ICU admission criteria and at assessing the prognosis implications of their severity level. To define severe CAP (SCAP) one should consider parameters that include the pathophysiology, risk factors/comorbidities and associated diagnostic elements such as clinical, laboratory (etiology) and imaging findings. Several severity scores were developed to scale appropriately patients requiring hospitalization. Their application stratifies the severity and predicts prognosis. Several factors are implicated in worse prognosis, including length of stay in ICU and delayed admission. The prognostic value of biomarkers such as procalcitonin, C-reactive protein, plasma cortisol and some interleukins, as well as socioeconomic status, genetic variability, anti-inflammatory drugs intake, mechanical ventilation and monitoring of guidelines was also assessed. In conclusion, the most commonly agreed definition of SCAP continues to be a CAP that requires hospitalization in ICU, being the Streptococcus pneumoniae the most frequent etiologic agent. Among the various severity scores available, the directives IDSA / ATS 2007 turned out to be the most balanced and its application has resulted in a significant positive impact on prognosis. It is expected that future research on inflammatory biomarkers may improve the diagnostic accuracy and prognosis in this diseas

Lateralization in the Invertebrate Brain: Left-Right Asymmetry of Olfaction in Bumble Bee, Bombus terrestris

Brain and behavioural lateralization at the population level has been recently hypothesized to have evolved under social selective pressures as a strategy to optimize coordination among asymmetrical individuals. Evidence for this hypothesis have been collected in Hymenoptera: eusocial honey bees showed olfactory lateralization at the population level, whereas solitary mason bees only showed individual-level olfactory lateralization. Here we investigated lateralization of odour detection and learning in the bumble bee, Bombus terrestris L., an annual eusocial species of Hymenoptera. By training bumble bees on the proboscis extension reflex paradigm with only one antenna in use, we provided the very first evidence of asymmetrical performance favouring the right antenna in responding to learned odours in this species. Electroantennographic responses did not reveal significant antennal asymmetries in odour detection, whereas morphological counting of olfactory sensilla showed a predominance in the number of olfactory sensilla trichodea type A in the right antenna. The occurrence of a population level asymmetry in olfactory learning of bumble bee provides new information on the relationship between social behaviour and the evolution of population-level asymmetries in animals

A multimodal approach for tracing lateralization along the olfactory pathway in the honeybee through electrophysiological recordings, morpho-functional imaging, and behavioural studies

Recent studies have revealed asymmetries between the left and right sides of the brain in invertebrate species. Here we present a review of a series of recent studies from our labs, aimed at tracing asymmetries at different stages along the honeybee's (Apis mellifera) olfactory pathway. These include estimates of the number of sensilla present on the two antennae, obtained by scanning electron microscopy, as well as electroantennography recordings of the left and right antennal responses to odorants. We describe investigative studies of the antennal lobes, where multi-photon microscopy is used to search for possible morphological asymmetries between the two brain sides. Moreover, we report on recently published results obtained by two-photon calcium imaging for functional mapping of the antennal lobe aimed at comparing patterns of activity evoked by different odours. Finally, possible links to the results of behavioural tests, measuring asymmetries in single-sided olfactory memory recall, are discussed.Comment: 28 pages, 8 figure

Brain-behavioural olfactory asymmetries in Apoidea

Lateralization of the nervous system enhances optimization of neural circuitry and parallel processing in individual organisms. Over groups of individuals, brain-behavioural asymmetries might present a direction in the occurrence of the bias (the majority of the individuals showing the same direction at the population level) that has been mathematically demonstrated to be an evolutionarily stable strategy in social groups, thus optimizing coordination and cooperation. The superfamily Apoidea represents a group in which both the study of the appearance of population-level asymmetries and advantages in individual organisms (e.g., in the A. mellifera model) can be exploited. Here I described a study on olfactory lateralization in a primitively eusocial species of Apoidea, B. terrestris. I reported here that this species showed a direction in the behavioural asymmetry of short-term odour memory, but only individual-level differences in odour detection at the periphery of the nervous system. Moreover, B. terrestris showed a morphological difference at the level of the population in the number of structures where olfactory neurons are housed. In the same subfamily Apoidea, the perennial eusocial honeybee, A. mellifera, is a good candidate for assessing neural correlates of odour asymmetries. Lateralization in olfactory memory was reported in this species in the past; here I performed for the first time a study of anatomical and functional asymmetries within the brain, in the first olfactory neuropils, the antennal lobes. I measured a subset of glomeruli in naïve individuals and found symmetrical volumes between the sides for those glomeruli that are mainly activated by odours that show lateralization in behvaiour. Furthermore, I performed single-antenna recall tests, conditioning bees to extend their proboscis (in the so-called PER paradigm) in association with those odours that more strongly activated functional responses in the selected glomerular subset. The behavioural tests showed an odour dependency in the capacity of bees to recall compounds with the two antennae. A broader subset of glomeruli was measured after long-term memory formation and symmetrical volumes were confirmed in all glomerular classes revealing also memory-dependent shrinkage effect. At the functional level, I performed in vivo calcium imaging data of the bee antennal lobes. Odor-evoked activity maps were recorded with two-photon microscopy allowing for better spatial and temporal resolution compared to conventional fluorescence microscopy. A first comparison between sides from wide-field fluorescence microscopy data showed a left/right difference in distance between odour representations and different mixture interactions within each lobe. In the same social species, A.mellifera, I reported the results of experiments measuring social interactions between pairs of bees with only one antenna in use, revealing that animals tested with only their right antenna in use exhibited better social context-dependent behaviours. Overall, these results provide new evidence for the occurrence of behavioural lateralizations at the population level, and identify some of their possible anatomical and functional correlates. Finally, in relation to previous studies these results tighten the link between the occurrence of population-level asymmetries and their evolution in a social context

Effetti della pressione sui capillari retinici ex vivo

Il glaucoma - la più comune causa di cecità irreversibile - è caratterizzato da una perdita progressiva delle cellule ganglionari della retina. Il maggiore fattore di rischio per questa patologia è l’elevata pressione intraoculare, e al momento, la riduzione della pressione è l’unico strumento efficace per rallentare la progressione del glaucoma. Questa terapia è però solo preventiva e una volta che le cellule ganglionari sono compromesse, il danno visivo risulta permanente. Al fine di contrastare questa malattia, è pertanto necessario comprendere come l’aumento della pressione danneggi i neuroni retinici. Molteplici fattori sembrano coinvolti. Schematicamente, si pensa che un aumento pressorio prolungato danneggi meccanicamente gli assoni retinici all’uscita del nervo ottico e che a questo si affianchino gli effetti deleteri di una ridotta perfusione sanguigna indotta dall’aumento di pressione. Diversi studi documentano un minor flusso sanguigno e un ridotto calibro dei vasi peripapillari in pazienti affetti da glaucoma e in modelli animali di glaucoma, ma questi studi sono solo correlativi. Inoltre, essi sono limitati ad arterie, vene ed arteriole poiché non esistono strumenti in grado di visualizzare i capillari dell’occhio in vivo. Questa limitazione è piuttosto severa dato che nel sistema nervoso centrale si stima che i capillari contribuiscano per il 90% all’apporto metabolico al tessuto. Per contribuire a definire gli effetti della pressione sui capillari retinici, abbiamo condotto esperimenti di imaging cellulare su retine di ratto espiantate soggette ad insulti pressori controllati. In particolare abbiamo indagato se e come un insulto pressorio transiente alteri il calibro dei capillari e la loro risposta ad uno stimolo vasocostrittore. I nostri risultati mostrano che transienti pressori elevati non inducono modificazioni significative del calibro dei capillari trattati rispetto alle retine di controllo. Tuttavia, dopo stimolazione pressoria, i capillari mostrano un’alterata reattività all’Endotelina-1 rispetto ai controlli. Questi dati indicano che: 1. l’aumento della pressione induce alterazioni funzionali dei capillari retinici; 2. tali alterazioni si protraggono oltre la durata dell’elevazione di pressione. Questi risultati corroborano l’ipotesi di un coinvolgimento degli effetti della pressione sui vasi retinici nella progressione della patologia glaucomatosa

Temporal and structural neural asymmetries in insects

Neural asymmetries of the bilateral parts of the nervous system are found throughout the animal kingdom. The relative low complexity and experimental accessibility of the insect nervous system makes it well suited for studying the functions of neural asymmetries and their underlying mechanisms. Recent findings in insects reveal hardwired asymmetries in their peripheral and central nervous systems, which affect sensory perception, motor behaviours and cognitive-related tasks. Together, these findings underscore the tendency of the nervous system to segregate between the activities of its right and left sides either transiently or as permanent lateralized specializations

Acute Application of Imidacloprid Alters the Sensitivity of Direction Selective Motion Detecting Neurons in an Insect Pollinator

Cholinergic pesticides, such as the neonicotinoid imidacloprid, are the most important insecticides used for plant protection worldwide. In recent decades, concerns have been raised about side effects on non-target insect species, including altered foraging behavior and navigation. Although pollinators rely on visual cues to forage and navigate their environment, the effects of neonicotinoids on visual processing have been largely overlooked. To test the effect of acute treatment with imidacloprid at known concentrations in the brain, we developed a modified electrophysiological setup that allows recordings of visually evoked responses while perfusing the brain in vivo. We obtained long-lasting recordings from direction selective wide-field, motion sensitive neurons of the hoverfly pollinator, Eristalis tenax. Neurons were treated with imidacloprid (3.9 μM, 0.39 μM or a sham control treatment using the solvent (dimethylsulfoxide) only. Exposure to a high, yet sub-lethal concentration of imidacloprid significantly alters their physiological response to motion stimuli. We observed a general effect of imidacloprid (3.9 μM) increasing spontaneous activity, reducing contrast sensitivity and giving weaker directional tuning to wide-field moving stimuli, with likely implications for errors in flight control, hovering and routing. Our electrophysiological approach reveals the robustness of the fly visual pathway against cholinergic perturbance (i.e., at 0.39 μM) but also potential threatening effects of cholinergic pesticides (i.e., evident at 3.9 μM) for the visual motion detecting system of an important pollinator