Neural Correlates of Social Behavior in Mushroom Body Extrinsic Neurons of the Honeybee Apis mellifera

The social behavior of honeybees (Apis mellifera) has been extensively investigated, but little is known about its neuronal correlates. We developed a method that allowed us to record extracellularly from mushroom body extrinsic neurons (MB ENs) in a freely moving bee within a small but functioning mini colony of approximately 1,000 bees. This study aimed to correlate the neuronal activity of multimodal high-order MB ENs with social behavior in a close to natural setting. The behavior of all bees in the colony was video recorded. The behavior of the recorded animal was compared with other hive mates and no significant differences were found. Changes in the spike rate appeared before, during or after social interactions. The time window of the strongest effect on spike rate changes ranged from 1 s to 2 s before and after the interaction, depending on the individual animal and recorded neuron. The highest spike rates occurred when the experimental animal was situated close to a hive mate. The variance of the spike rates was analyzed as a proxy for high order multi-unit processing. Comparing randomly selected time windows with those in which the recorded animal performed social interactions showed a significantly increased spike rate variance during social interactions. The experimental set-up employed for this study offers a powerful opportunity to correlate neuronal activity with intrinsically motivated behavior of socially interacting animals. We conclude that the recorded MB ENs are potentially involved in initiating and controlling social interactions in honeybees

Dissolved storage glycans shaped the community composition of abundant bacterioplankton clades during a North Sea spring phytoplankton bloom

Background: Blooms of marine microalgae play a pivotal role in global carbon cycling. Such blooms entail successive blooms of specialized clades of planktonic bacteria that collectively remineralize gigatons of algal biomass on a global scale. This biomass is largely composed of distinct polysaccharides, and the microbial decomposition of these polysaccharides is therefore a process of prime importance. Results: In 2020, we sampled a complete biphasic spring bloom in the German Bight over a 90-day period. Bacterioplankton metagenomes from 30 time points allowed reconstruction of 251 metagenome-assembled genomes (MAGs). Corresponding metatranscriptomes highlighted 50 particularly active MAGs of the most abundant clades, including many polysaccharide degraders. Saccharide measurements together with bacterial polysaccharide utilization loci (PUL) expression data identified β-glucans (diatom laminarin) and α-glucans as the most prominent and actively metabolized dissolved polysaccharide substrates. Both substrates were consumed throughout the bloom, with α-glucan PUL expression peaking at the beginning of the second bloom phase shortly after a peak in flagellate and the nadir in bacterial total cell counts. Conclusions: We show that the amounts and composition of dissolved polysaccharides, in particular abundant storage polysaccharides, have a pronounced influence on the composition of abundant bacterioplankton members during phytoplankton blooms, some of which compete for similar polysaccharide niches. We hypothesize that besides the release of algal glycans, also recycling of bacterial glycans as a result of increased bacterial cell mortality can have a significant influence on bacterioplankton composition during phytoplankton blooms. [MediaObject not available: see fulltext.

Resection of the primary tumour versus no resection prior to systemic therapy in patients with colon cancer and synchronous unresectable metastases (UICC stage IV): SYNCHRONOUS - a randomised controlled multicentre trial (ISRCTN30964555)

<p>Abstract</p> <p>Background</p> <p>Currently, it remains unclear, if patients with colon cancer and synchronous unresectable metastases who present without severe symptoms should undergo resection of the primary tumour prior to systemic chemotherapy. Resection of the primary tumour may be associated with significant morbidity and delays the beginning of chemotherapy. However, it may prevent local symptoms and may, moreover, prolong survival as has been demonstrated in patients with metastatic renal cell carcinoma. It is the aim of the present randomised controlled trial to evaluate the efficacy of primary tumour resection prior to systemic chemotherapy to prolong survival in patients with newly diagnosed colon cancer who are not amenable to curative therapy.</p> <p>Methods/design</p> <p>The SYNCHRONOUS trial is a multicentre, randomised, controlled, superiority trial with a two-group parallel design. Colon cancer patients with synchronous unresectable metastases are eligible for inclusion. Exclusion criteria are primary tumour-related symptoms, inability to tolerate surgery and/or systemic chemotherapy and history of another primary cancer. Resection of the primary tumour as well as systemic chemotherapy is provided according to the standards of the participating institution. The primary endpoint is overall survival that is assessed with a minimum follow-up of 36 months. Furthermore, it is the objective of the trial to assess the safety of both treatment strategies as well as quality of life.</p> <p>Discussion</p> <p>The SYNCHRONOUS trial is a multicentre, randomised, controlled trial to assess the efficacy and safety of primary tumour resection before beginning of systemic chemotherapy in patients with metastatic colon cancer not amenable to curative therapy.</p> <p>Trial registration</p> <p><a href="http://www.controlled-trials.com/ISRCTN30964555">ISRCTN30964555</a></p

Transgenic Overexpression of the Type I Isoform of Neuregulin 1 Affects Working Memory and Hippocampal Oscillations but not Long-term Potentiation

Neuregulin 1 (NRG1) is a growth factor involved in neurodevelopment and plasticity. It is a schizophrenia candidate gene, and hippocampal expression of the NRG1 type I isoform is increased in the disorder. We have studied transgenic mice overexpressing NRG1 type I (NRG1tg-type I) and their wild-type littermates and measured hippocampal electrophysiological and behavioral phenotypes. Young NRG1tg-type I mice showed normal memory performance, but in older NRG1tg-type I mice, hippocampus-dependent spatial working memory was selectively impaired. Hippocampal slice preparations from NRG1tg-type I mice exhibited a reduced frequency of carbachol-induced gamma oscillations and an increased tendency to epileptiform activity. Long-term potentiation in NRG1tg-type I mice was normal. The results provide evidence that NRG1 type I impacts on hippocampal function and circuitry. The effects are likely mediated via inhibitory interneurons and may be relevant to the involvement of NRG1 in schizophrenia. However, the findings, in concert with those from other genetic and pharmacological manipulations of NRG1, emphasize the complex and pleiotropic nature of the gene, even with regard to a single isoform

Effects of lorazepam on saccadic eye movements: the role of sex, task characteristics and baseline traits

Medical Research Council; National Institute for Health Research; Mental Health Biomedical Research Centre at South London; Maudsley NHS Foundation Trust; Institute of Psychiatry, Psychology; Neuroscience, King’s College London

Labortests zur Navigation bei Hummeln: Pestizidauswirkungen und neuronale Korrelate

The utilization of bumblebees in the laboratory setting is increasing primarily for the purpose of behavioral analysis and neural recordings. Their remarkable physiological resilience and their willingness to adapt to diverse environmental conditions render them exceptionally suitable for a wide range of experimental investigations. Moreover, they represent the vast group of wild bees, which are also struggling with the current problems arising from agricultural mismanagement. To find a suitable setup to perform behavioral tests accompanied by electrophysiological recordings for bumblebees, a novel experimental apparatus was designed and constructed. The bumblebee could autonomously navigate between the colony and the test/feeding arena. Initially, the focus was set on the normal behavior and development of the colonies within this controlled artificial environment. Through a series of iterative refinements, a training protocol was established. The bumblebees had to learn a specific feeding place marked by a local cue and matching panorama. Notably, extinction tests revealed an enhanced behavior towards the learned goals. This change in behavior is proving, that the artificial arena with the connection to the colony and animals foraging on their own motivation adequately fulfills the requisite criteria for conducting such experiments. Furthermore, tests were performed treating animals with Calypso®, an insecticide formulation with neonicotinoid Thiacloprid. The extinction tests resulted in a shift in behavioral patterns towards the border area compared to the controls, displaying a change in exploratory behavior. These findings serve as evidence, that the experimental procedure is suitable for laboratory based navigational experiments researching sub-lethal effects of treatments. Electrophysiological recordings were performed on trained animals using an established setup, yielding stable and sortable data. However, no discernible pattern indicative of memory retrieval was observed. Instead, subtle indications of involvement in exploratory behavior or exploratory learning were detected. The limitations of comparing simultaneously recorded neurons prevented the identification of a network pattern for learned object identification. Nevertheless, the study emphasizes the suitability of the setup for conducting electrophysiological recordings in trained bumblebees. The recommendation to upgrade the outdated recording devices is made to enable long-lasting multi-unit recordings and facilitate further intriguing analyses.Hummeln werden im Labor zunehmend für Verhaltensanalysen und neuronale Aufzeichnungen eingesetzt. Aufgrund ihrer bemerkenswerten physiologischen Widerstandsfähigkeit und ihrer Bereitschaft, sich an unterschiedliche Umweltbedingungen anzupassen, eignen sie sich hervorragend für ein breites Spektrum an experimentellen Untersuchungen. Außerdem stellen sie die größte Gruppe der Wildbienen dar, welche ebenfalls mit den aktuellen Problemen zu kämpfen haben, die sich aus der Misswirtschaft in der Landwirtschaft ergeben. Um einen geeigneten Aufbau für die Durchführung von Verhaltenstests in Verbindung mit elektrophysiologischen Aufzeichnungen für Hummeln zu finden, wurde ein neuartiger Versuchsapparat entworfen und gebaut. Die Hummeln konnten autonom zwischen der Kolonie und der Test-/Fütterungsarena navigieren. Anfänglich lag der Schwerpunkt auf dem normalen Verhalten und der Entwicklung der Kolonien in dieser kontrollierten künstlichen Umgebung. Durch eine Reihe von iterativen Verfeinerungen wurde ein Trainingsprotokoll erstellt. Die Hummeln mussten einen bestimmten Futterplatz erlernen, der durch einen lokalen Hinweis und ein passendes Panorama gekennzeichnet war. Die Extinktionstests zeigten ein verbessertes Verhalten gegenüber den erlernten Zielen. Diese Verhaltensänderung beweist, dass die künstliche Arena mit der Verbindung zur Kolonie und den Tieren, die aus eigener Motivation auf Futtersuche gehen, die erforderlichen Kriterien für die Durchführung solcher Experimente ausreichend erfüllt. Außerdem wurden Tests durchgeführt, bei denen die Tiere mit Calypso® behandelt wurden, einer Insektizid-Formulierung mit dem Neonicotinoid Thiacloprid. Die Extinktionstests führten zu einer Verschiebung der Verhaltensmuster in Richtung des Randbereichs im Vergleich zu den Kontrollen, was eine Änderung des Erkundungsverhaltens darstellt. Diese Ergebnisse zeigen, dass das Versuchsverfahren für Navigationsexperimente im Labor zur Erforschung subletaler Effekte von Behandlungen geeignet ist. Die elektrophysiologischen Aufzeichnungen wurden an trainierten Tieren mit einem etablierten Aufbau durchgeführt und ergaben stabile und verwertbare Daten. Es wurde jedoch kein erkennbares Muster beobachtet, das auf das Abrufen von Gedächtnisinhalten hinweist. Stattdessen wurden schwache Hinweise auf eine Beteiligung am Erkundungsverhalten oder am Erkundungslernen festgestellt. Die Beschränkungen des Vergleichs gleichzeitig aufgezeichneter Neuronen verhinderten die Identifizierung eines Netzwerkmusters für die erlernte Objektidentifikation. Dennoch unterstreicht die Studie die Eignung des Versuchsaufbaus für die Durchführung elektrophysiologischer Ableitungen bei trainierten Hummeln. Es wird empfohlen, die veralteten Aufzeichnungsgeräte aufzurüsten, um langanhaltende Multi-Unit-Aufzeichnungen zu ermöglichen und weitere interessante Analysen zu erleichtern

A tree of life? Multivariate logistic outcome-prediction in disorders of consciousness

Steppacher I, Fuchs P, Kaps M, Nussbeck FW, Kißler J. A tree of life? Multivariate logistic outcome-prediction in disorders of consciousness. BRAIN INJURY. 2019;34(3):399-406.Background: Clinical outcome of patients with disorders of consciousness (DOC) is seen as generally very poor. Here, we specify individual outcome chances for patients with DOC on the basis of clinical and event-related-potentials (ERPs) data and identify subgroups, who vary substantially regarding their outcome chances. Methods: We employed data from 102 patients and used standard clinical protocol data (age, etiology, diagnosis, gender), sensory (N100, Mismatch-Negativity) and cognitive (P300, N400) ERPs to predict patients' recovery rates. Results: Two significant prediction models emerged: In both, subgroups of patients with good (51%, tree 1) to very good recovery chances (97%, tree 2) could be identified. The first model was obtained from standard clinical data. The second model included cognitive ERPs and resulted in considerably better patient classification. Moreover, when taking cognitive ERPs into account, the standard protocol data did not add further significant information, neither did sensory ERPs. Conclusion: The presented information about outcome chances of individual patients with DOC will be vital for these patients and critical for clinical professionals who have to direct specialized treatments and council relatives. Legal guardians and families, in turn, need to know what to expect in the future in order to prepare for the challenges ahead

Synergistic olfactory processing for social plasticity in desert locusts

Abstract Desert locust plagues threaten the food security of millions. Central to their formation is crowding-induced plasticity, with social phenotypes changing from cryptic (solitarious) to swarming (gregarious). Here, we elucidate the implications of this transition on foraging decisions and corresponding neural circuits. We use behavioral experiments and Bayesian modeling to decompose the multi-modal facets of foraging, revealing olfactory social cues as critical. To this end, we investigate how corresponding odors are encoded in the locust olfactory system using in-vivo calcium imaging. We discover crowding-dependent synergistic interactions between food-related and social odors distributed across stable combinatorial response maps. The observed synergy was specific to the gregarious phase and manifested in distinct odor response motifs. Our results suggest a crowding-induced modulation of the locust olfactory system that enhances food detection in swarms. Overall, we demonstrate how linking sensory adaptations to behaviorally relevant tasks can improve our understanding of social modulation in non-model organisms

Social modulation of individual preferences in cockroaches

In social species, decision-making is both influenced by, and in turn influences, the social context. This reciprocal feedback introduces coupling across scales, from the neural basis of sensing, to individual and collective decision-making. Here, we adopt an integrative approach investigating decision-making in dynamical social contexts. When choosing shelters, isolated cockroaches prefer vanillin-scented (food-associated) shelters over unscented ones, yet in groups, this preference is inverted. We demonstrate that this inversion can be replicated by replacing the full social context with social odors: presented alone food and social odors are attractive, yet when presented as a mixture they are avoided. Via antennal lobe calcium imaging, we show that neural activity in vanillin-responsive regions reduces as social odor concentration increases. Thus, we suggest that the mixture is evaluated as a distinct olfactory object with opposite valence, providing a mechanism that would naturally result in individuals avoiding what they perceive as recently exploited resources.publishe