bioRxiv Science⌕ Search

Biology subjects

Verbe, A.

Publications and source records attributed to Verbe, A..

3 recordsLinked to original sources

Sharp and Fast Dynamic Extraction and Tracking of Emitted Cellular Transients

Genetically encoded fluorescent sensors have expanded our ability to image cellular activity and transmitter release. Yet, sparse and low-salience events remain difficult to resolve against complex and fluctuating fluorescence backgrounds. Here we introduce DETECT, Dynamic Extraction and Tracking of Emitted Cellular Transients, which combines adaptive background suppression, probabilistic classification and multi-object tracking to extract fluorescence events while preserving their identity. Across synthetic datasets, DETECT improved detection and segmentation accuracy and reduced computational cost relative to established event-based methods. We validated DETECT across confocal, two-photon and miniscope imaging, ex vivo and in vivo, using calcium indicators and monoamine sensors. Beyond its technical performance, DETECT extends event-based analysis to low-salience fluorescence signals while resolving events spanning broad ranges of amplitude, morphology and dynamics. By resolving spontaneous dopamine and noradrenaline signals as distinct, trackable release events, DETECT reveals the spatiotemporal organization of neuromodulatory activity and provides a broadly applicable approach to quantitative fluorescence analysis.

neuroscience↗

A multisensory, bidirectional, valence encoder guides behavioral decisions

A key function of the brain is to categorize sensory cues as repulsive or attractive and respond accordingly. While we have some understanding of how sensory information is processed in the sensory periphery, the classification of cues according to valence in central brain circuits is less well understood. Here, we addressed this question in the Drosophila larva, where we could leverage the synaptic resolution connectome to determine where innate and learnt information from distinct aversive and appetitive sensory modalities converges; and combine this with imaging and manipulation of neural activity to determine how valence information is encoded and used to guide navigation. We found that information from multiple innately aversive and attractive sensory modalities converges onto a common output neuron of the learning circuit, specifically the Mushroom Body output neuron, MBON-m1. We discovered that this neuron is required for navigating both attractive odor and aversive temperature cues and is activated by attractive cues, such as food odour and sugar, and inhibited by different aversive cues, such as cooling, salt, or non-food odors. Together, our study reveals a neuron that bi-directionally encodes valence and controls actions.

neuroscience↗

Flies tune the sensitivity of their multifunctional gyroscope.

Locomotion requires navigating unpredictable and complex environments, demanding both stability and maneuverability within short timeframes. This is particularly important for flying insects, and the true flies (Diptera) stand out among this group for their impressive flight capabilities. Flies aerial abilities are partially attributed to halteres, tiny club-shaped structures that evolved from the hindwings and play a crucial role in flight control. Halteres oscillate during flight, in antiphase with the wings, providing rhythmic input to the wing steering system via arrays of embedded mechanosensors called campaniform sensilla. These sensor arrays convey timing information to the wing steering muscles, but linking haltere sensor location to sensor activity and the functional organization of the wing steering system remains a central challenge. Here, we use in vivo calcium imaging during tethered flight to obtain population-level recordings of the haltere sensory afferents in specific fields of sensilla. We find that haltere feedback is continuously modulated by visual stimuli to stabilize flight. Additionally, this feedback is present during saccades and help flies actively maneuver. We also find that the halteres multifaceted role arises from the steering muscles of the haltere itself, regulating haltere stroke amplitude to modulate campaniform activity. Taken together, our results underscore the crucial role of biomechanics in regulating the dynamic range of sensors and provide insight into how the sensory and motor systems of flies coevolved. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/583703v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1296750org.highwire.dtl.DTLVardef@13dc425org.highwire.dtl.DTLVardef@185de0org.highwire.dtl.DTLVardef@1bb38de_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗