Gerit Arne Linneweber

Freie Universität Berlin | FUB · Division of Neurobiology and Behavior

During adaptive angiogenesis, a key process in the etiology and treatment of cancer and obesity, the vasculature changes to meet the metabolic needs of its target tissues. Although the cues governing vascular remodeling are not fully understood, target-derived signals are generally believed to underlie this process. Here, we identify an alternative...

Diversity from development When given a line to follow, some fruit flies do so carefully and others weave. Linneweber et al. now show that these behaviors are stable for an individual but diverse in an isogenic population. Key to generating individual diversity in the population is the inherent chaos of normal development. A set of neurons in the v...

Why are we all different? This is one of the oldest and most contested scientific questions. Naturally, the brain is often the focus of these discussions, as it is the control center for our body and behavior. The debate of "nature vs nurture" tried to determine whether genetics or the environment shape individual differences. Studies on identical...

Over the past decade, several studies have demonstrated that idiosyncratic animal behaviors remain stable over long time periods. The stability of individually variable behaviors over time is often referred to as an animal’s individuality, or personality. However, most experimental studies have focused on individuality in a single, well-defined env...

Connections between neurons can be mapped by acquiring and analysing electron microscopic brain images. In recent years, this approach has been applied to chunks of brains to reconstruct local connectivity maps that are highly informative 1–6 , but nevertheless inadequate for understanding brain function more globally. Here we present a neuronal wi...

A catalogue of neuronal cell types has often been called a 'parts list' of the brain1, and regarded as a prerequisite for understanding brain function2,3. In the optic lobe of Drosophila, rules of connectivity between cell types have already proven to be essential for understanding fly vision4,5. Here we analyse the fly connectome to complete the l...

The fruit fly Drosophila melanogaster has emerged as a key model organism in neuroscience, in large part due to the concentration of collaboratively generated molecular, genetic and digital resources available for it. Here we complement the approximately 140,000 neuron FlyWire whole-brain connectome1 with a systematic and hierarchical annotation of...

Over the past decade, several studies have demonstrated that idiosyncratic animal behaviors remain stable over long time periods. The stability of individually variable behaviors over time is often referred to as an animal’s individuality, or personality. However, most experimental studies have focused on individuality in a single, well-defined env...

Over the past decade, several studies have demonstrated that idiosyncratic animal behaviors remain stable over long time periods. The stability of individually variable behaviors over time is often referred to as an animal's individuality, or personality. However, most experimental studies have focused on individuality in a single, well-defined env...

Over the past decade, several studies have demonstrated that idiosyncratic animal behaviors remain stable over long time periods. The stability of individually variable behaviors over time is often referred to as an animal’s individuality, or personality. However, most studies have focused on individuality in a single, well-defined environmental co...

The development of neuronal connectivity requires stabilization of dynamic axonal branches at sites of synapse formation. Models that explain how axonal branching is coupled to synaptogenesis postulate molecular regulators acting in a spatiotemporally restricted fashion to ensure branching toward future synaptic partners while also stabilizing the...

The emergence of neuronal wiring specificity requires stabilization of dynamic axonal branches at sites of selective synapse formation. Models that explain how axonal branching is coupled to synaptogenesis postulate molecular regulators acting in a spatiotemporally restricted fashion. We report that Epidermal Growth Factor Receptor (EGFR) activity...

Variability of synapse numbers and partners despite identical genes reveals the limits of genetic determinism. Here, we use developmental temperature as a non-genetic perturbation to study variability of brain wiring and behavior in Drosophila. Unexpectedly, slower development at lower temperatures increases axo-dendritic branching, synapse numbers...

Variability of synapse numbers and partners despite identical genes reveals limits of genetic determinism. Non-genetic perturbation of brain wiring can therefore reveal to what extent synapse formation is precise and absolute, or promiscuous and relative. Here, we show the role of relative partner availability for synapse formation in the fly brain...

Rab GTPases are molecular switches that regulate membrane trafficking in all cells. Neurons have particular demands on membrane trafficking and express numerous Rab GTPases of unknown function. Here, we report the generation and characterization of molecularly defined null mutants for all 26 rab genes in Drosophila. In flies, all rab genes are expr...

Brain wiring is remarkably precise, yet most neurons readily form synapses with incorrect partners when given the opportunity. Dynamic axon-dendritic positioning can restrict synaptogenic encounters, but the spatiotemporal interaction kinetics and their regulation remain essentially unknown inside developing brains. Here we show that the kinetics o...

The genome versus experience dichotomy has dominated understanding of behavioral individuality. By contrast, the role of nonheritable noise during brain development in behavioral variation is understudied. Using Drosophila melanogaster, we demonstrate a link between stochastic variation in brain wiring and behavioral individuality. A visual system...

Brain wiring is remarkably precise, yet most neurons readily form synapses with incorrect partners when given the opportunity. Dynamic axon-dendritic positioning can restrict synaptogenic encounters, but the spatiotemporal interaction kinetics and their regulation remain essentially unknown inside developing brains. Here we show that the kinetics o...

The genome versus experience, or “Nature versus Nurture”, debate has dominated our understanding of individual behavioral variation. A third factor, namely variation in complex behavior potentially due to non-heritable “developmental noise” in brain development, has been largely ignored. Using the Drosophila vinegar fly we demonstrate a causal link...

Isolation profoundly influences social behavior in all animals. In humans, isolation has serious effects on health. Drosophila melanogaster is a powerful model to study small-scale, temporally-transient social behavior. However, longer-term analysis of large groups of flies is hampered by the lack of effective and reliable tools. We built a new ima...

Describes a bipartite graph for splitting connected components containing interacting flies. The nodes P1,.., P4 represent the individual flies in the previous frame while C1 and C2 represent the candidate connected components containing multiple interacting flies. C11, C21 are duplicated nodes. After solving the assignment problem, a minimum weigh...

Original social networks and corresponding average network. On the left are the different networks constructed from 10 biological repeats of an experiment under the same conditions. Each network was constructed from its corresponding adjacency matrix, normalized to the maximum number of interactions within that matrix. On the right is the average n...

Genome-wide analysis and physiological changes. (A, B) Scatter plots of log2 of fold changes versus log10 of gene counts on days 2 and 3. (C) GO analysis shows up-regulated genes on day 2 are mainly related to iron ion binding. (D) GO analysis shows down-regulated genes on day 2 are mainly clustered into carboxylase and amino metabolic processes. (...

Tracking results of 16 walking flies in the Flyworld arena by Flytracker. Each fly is labelled with a number and a distinct colour for its trajectory (+/- 0.5 s). The video is a 30 second clip of a 1-hour tracking video. (MP4)

A 6-second video clip for manual checking the tracking results from a 50-fly one-hour video. Each time, the observer focuses on one single fly (Fly 1 in this video in a black box with its track as black dots in frames [-30, +30]). All flies were labeled with their corresponding identity numbers to help the observer to check if there are missing or...

Classification of a touch behavior between two flies. An interactor approaches the rear part of the interacted and the interaction is considered valid only when two flies maintain relative positions for more than 15 frames (~0.5 s). (MP4)

Social isolation induced differentially alternative splicing events. Note. PATH1&2 A path includes the alternative exons and the flanking exons from one of the two isoforms of the event. The two paths of an event describe the two alternatively used isoforms of the splicing event. Event Types: A5SS: Alternative 5’ splicing sites; AFE: Alternative fi...

Global parameters of sample network calculated for the whole group of objects. (PDF)

Documents of Flyworld and Buridan setup designs. In the zip file, there are 3D model designs of key parts of Flyworld used in this experiment in folder “Flyworld” and designs of Buridan’s Paradigm for testing Flytracker in the folder “Buridan setup”. All 3D designs are made using SolidWorks which can be viewed and measured using the free software “...

Social parameters calculated from the isolation experiment. The individual network parameters In-Degree, Out-Degree and Degree all show significant differences with p<0.0001. (D) No significant difference between isolated and control groups was observed for the local parameter Betweenness Centrality, demonstrating that pivot flies do not significan...

The example network constructions. (A) The matrix consists of the number of interactions between any two flies. For example, row 1 column 2 indicates 2 interactions from fly X1 to fly X2, which is shown in (B) as an arrow from X1 to X2, whose thickness is proportional to the number of interactions. (TIF)

A 10-second video clip with tracking results of 10 flies by Flytracker from Buridan’s paradigm. Two female and eight male flies with clipped wings walking on the platform surrounded by water to prevent them walking outside of the platform. All flies were labeled with detected identity. (MP4)

Evolution of social network parameters over different days of isolation. Different parameters show changes over time and differences between control (blue) and isolated (red) groups. Significance is noted with asterisks, the number of which represent the negative orders of magnitude of p value. Data are shown in median with interquartile ranges (n...

Correlation analysis among different parameters between control and isolation flies on day 1, 2 and 6. Each filled circle represents the correlation coefficient with p value less than 0.01. The size and color of the circle are proportional to the correlation coefficients and blue colors indicate positive correlations while red colors indicate negat...

Tracking results of 10 walking flies in the Flyworld arena by Flytracker. Each fly is labelled blue while trajectories are labelled with different colours. The video is a 15 minute clip of a 1-hour tracking video. (MP4)

Tracking results of 50 walking flies in the Flyworld arena by Flytracker. Each fly is labelled with a distinct colour for its trajectory (from 0.5s before current position). The video is an 8 second clip of a 1-hour tracking video. (MP4)

An annotated video clip from a 6-min sample video showing the tracking errors by Ctrax on 10 flies walking in the Flyworld arena. The colored shapes represent different flies that Ctrax detects. This clip started from when the errors become severe. The errors include losing identity (no color contour covers the fly), swapping identity rapidly (chan...

Individual and local social network parameters of sample network calculated for each individual object. (PDF)

Fragile X syndrome (FXS) patients present neuronal alterations that lead to severe intellectual disability, but the underlying neuronal circuit mechanisms are poorly understood. An emerging hypothesis postulates that reduced GABAergic inhibition of excitatory neurons is a key component in the pathophysiology of FXS. Here, we directly test this idea...

Most animal tissues and organ systems are comprised of highly ordered arrays of varying cell types. The development of external sensory organs requires complex cell-cell communication in order to give each cell a specific identity and to ensure a regular distributed pattern of the sensory bristles. This involves both long and short range signaling...

The role of the central neuropeptide pigment-dispersing factor (PDF) in circadian timekeeping in Drosophila is remarkably similar to that of vasoactive intestinal peptide (VIP) in mammals. Like VIP, PDF is expressed outside the circadian network by neurons innervating the gut, but the function and mode of action of this PDF have not been characteri...

Invertebrate model organisms are powerful systems for uncovering conserved principles of animal biology. Despite widespread use in scientific communities, invertebrate research is often severely undervalued by laypeople. Here, we present a set of simple, inexpensive public outreach exercises aimed at explaining to the public why basic research on o...

One of the most challenging problems in developmental neurosciences is to understand the establishment and maintenance of specific membrane contacts between axonal, dendritic, and glial processes in the neuropils, which eventually secure neuronal connectivity. However, underlying cell recognition events are pivotal in other tissues as well. This br...

The Neph-like proteins IrreC/Rst, Kirre and the Nephrinlike proteins Hbs, SNS cooperate in the interaction of different polarized cell types. Here we describe their concerted action in the development of sensory organs at the anterior wing margin and add to the justification to give this protein ensemble a common name, the Irre Cell Recognition Mod...