Neuronal circuits

Understanding the fine-scale connectivity structure of neural networks is key to deciphering their behaviour. Motifs in network connectivity are instrumental in relating circuit structure to dynamical properties of neural activity, such as covariability and dimensionality [1]. Experiments have made significant progress in measuring precise neural connectivity: multi-patch experiments, as well as more recent studies in connectomics, have found that certain types of three-neuron (triplet) connectivity motifs are over- or underrepresented relative to chance (Fig.1A, [2,3]). However, it is still u

…to study formation and regeneration of neuronal circuits. Tools to visualize and manipulate cells of the axolotl nervous system with high efficiency, spatial and temporal precision are therefore greatly required. Recombinant adeno-associated viruses (AAVs) are frequently used for in vivo gene transfer of the nervous system but virus-mediated gene delivery to the axo

Most animals are born with a minimal repertoire of behaviors, which is gradually expanded as they grow and adapt to their changing needs, environments, and body morphology. The emergence of new functional capacities is associated with changes in the brain architecture, as new neurons become functional and new connections are formed. How brain maturation orchestrates phenotypic transformations during development is still an open question in behavioral neuroscience. Here, we investigate this question in Danionella cerebrum, a novel vertebrate model whose brain remains small and transparent up to

…mathematical models reproducing neuronal circuits. While cellular and subcellular resolution data have been extensively collected in animal models, experimental constraints have limited the acquisition of information about human neuronal cytoarchitectures and morphologies. In this context, high resolution data can be efficiently

Ethanol (EtOH) exposure during pregnancy can induce a range of physical, learning, and behavioral disorders in the newborn clinically referred as Fetal Alcohol Spectrum Disorder (FASD). Unfortunately, FASD is poorly understood, and the underlying mechanisms are not fully known. Here, we studied the role of AMPA receptors (AMPARs) in in vitro and in vivo models of prenatal alcohol exposure (PAE). For the in vitro study, immature rat organotypic hippocampal slices were exposed to EtOH (150 mM) for 7 days followed by 24 hours of withdrawal. For the in vivo study, female C57/Bl6 mice were exposed

…by a functional restoration of neuronal circuits. To do so, we are establishing state-of-the-art neuroscience tools in our model system, namely GCaMP imaging of neuronal activity, behavioral assays and optogenetic stimulation. Using these methods, we will investigate the visuomotor circuit of the axolotl in intact, injured and regenerating conditions.Rec

The nervous system orchestrates adaptive behaviors by intricately coordinating responses to internal cues and environmental stimuli. This involves integrating sensory input, managing competing motivational states, and drawing on past experiences to anticipate future outcomes. While traditional models attribute this complexity to interactions between the mesocorticolimbic system and hypothalamic centers, the specific nodes of integration have remained elusive. Recent research, including our own, sheds light on the midline thalamus's overlooked role in this process. We propose that the midline t

We build upon and expand the efficient coding and predictive information models of neurons, presenting a novel perspective that neurons not only predict but also actively influence their future inputs through their outputs. We introduce the concept of neurons as feedback controllers of their environments, a role traditionally considered computationally demanding, particularly when the dynamical system characterizing the environment is unknown. By harnessing a novel data-driven control framework, we illustrate the feasibility of biological neurons functioning as effective feedback controllers.

…reflect past experiences embedded in neuronal circuits. Moreover, spatiotemporal patterns involving whole-brain activities may also reflect a process that integrates information distributed over the entire brain, such as motor and visual information. Therefore, revealing such patterns may elucidate how the information is integrated to generate consc

During development, the complex neuronal circuitry of the brain arises from limited information contained in the genome. After the genetic code instructs the birth of neurons, the emergence of brain regions, and the formation of axon tracts, it is believed that neuronal activity plays a critical role in shaping circuits for behavior. Current AI technologies are modeled after the same principle: connections in an initial weight matrix are pruned and strengthened by activity-dependent signals until the network can sufficiently generalize a set of inputs into outputs. Here, we challenge these lea

The David Smith Lectures in Anatomical Neuropharmacology, Part of the 'Pharmacology, Anatomical Neuropharmacology and Drug Discovery Seminars Series', Department of Pharmacology, University of Oxford. The 15th David Smith Award Lecture in Anatomical Neuropharmacology will be delivered by Professor Tim Bliss, Visiting Professor at UCL and the Frontier Institutes of Science and Technology, Xi’an Jiaotong University, China, and is hosted by Professor Nigel Emptage. This award lecture was set up to celebrate the vision of Professor A David Smith, namely, that explanations of the action of drugs on

…stimuli, and study the underlying neuronal circuits, which are composed of the same neurons that are wired differently. By imaging receptor expression, calcium responses and glutamate secretion, we show tha

…Information-transmission pathways in neuronal structure, especially in complex connectomes, seem to favor specific recurrent motifs. For intrinsically directional and weighted networks such as those in the brain, it is particularly important to use methods that are sensitive to the weight-encoded information. We use new weighted methods to assess statistics of motives in the connectomes of various animals: \textit{C. elegans}, tadpole, drosophila,

Cerebral infection by the larvae of the cestode, Taenia solium (neurocysticercosis), is thought to be the leading cause of adult-acquired epilepsy worldwide. Despite this, little is known about the cellular mechanisms that underlie seizure development in this condition. In this talk I will present our recent data exploring multiple interactions between cestode larvae, neuroinflammatory processes and network excitability. We find that viable cestode larvae are able to strongly suppress microglial activation and inflammatory cytokine release with consequences for the modulation host neuroinflamm

The last decade in the field of neuroscience has been marked by intense debate on the meaning of the term fear. Whereas some have argued that fear (as well as other emotions) relies on cognitive capacities that are unique to humans, others view it as a negative state constructed from essential building blocks. This latter definition posits that fear states are associated with varying readouts that one could consider to be parallel processes or serial events tied to a specific hierarchy. Within this framework, innate defensive behaviors are considered to be common displays of fear states that l

Long-range projections link distant circuits in the brain, allowing efficient transfer of information between regions and synchronization of distributed patterns of neural activity. Understanding the functional roles of defined neuronal projection pathways requires temporally precise manipulation of their activity, and optogenetic tools appear to be an obvious choice for such experiments. However, we and others have previously shown that commonly-used inhibitory optogenetic tools have low efficacy and off-target effects when applied to presynaptic terminals. In my talk, I will present a new so

…of our research is to understand how neuronal circuits integrate sensory inputs and internal state and convert this information into behavioral responses.

…and in almost all their cases the circuits that enable tetra- or possibly even pentachromatic colour vision are not known. This includes the majority of birds, reptiles, amphibians, and bony fish. In the lab we study neuronal circuits for colour vision in non-mammalian vertebrates, with a focus on zebrafish, a tetr

…the critical step in the assembly of neuronal circuits. The assembly and maturation of synapses requires the contribution of secreted and membrane-associated proteins, with neuronal activity playing crucial roles in regulating synaptic strength, neuronal membrane properties, and neural circuit refinement. The molecular mechanisms of synapse assembly and refinement have been so far largely examined on a gene-by-gene basis and with a perspective fully centered on neuronal cells. However, in the last years, the invol

Densely mapping neuronal circuits at synaptic resolution is providing unprecedented insight into the formation and structure of the cerebral cortex. I’ll present recent advances and discuss what we can learn about precision, plasticity and possible patterns in mammalian neuronal circuits.

…processes, notably the development of neuronal circuits, that in turn control behaviour. An understanding of how neuronal circuits develop and function at the individual organism level is therefore essential