Synaptic transmission provides the basis for neuronal communication. When an action-potential propagates through the axonal arbour, it activates voltage-gated Ca2+ channels located in the vicinity of release-ready synaptic vesicles docked at the presynaptic active zone. Ca2+ ions enter the presynaptic terminal and activate the vesicular Ca2+ sensor, thereby triggering neurotransmitter release. This whole process occurs on a timescale of a few milliseconds. In addition to fast, synchronous release, which keeps pace with action potentials, many synapses also exhibit delayed asynchronous release that persists for tens to hundreds of milliseconds. In this talk I will demonstrate how experimentally constrained computational modelling of underlying biological processes can complement laboratory studies (using electrophysiology and imaging techniques) and provide insights into the mechanisms of synaptic transmission.

White matter microstructure underpins cognition and function in the human brain through the facilitation of neuronal communication, and the non-invasive characterization of this structure remains an elusive goal in the neuroscience community. Efforts to assess white matter microstructure are hampered by the sheer amount of information needed for characterization. Current techniques address this problem by representing white matter features with single scalars that are often not easy to interpret. Here, we address these issues by introducing tools from soft matter for the characterization of white matter microstructure. We investigate structure on a mesoscopic scale by analyzing its homogeneity and determining which regions of the brain are structurally homogeneous, or ``crystalline" in the context of materials science. We find that crystallinity is a reliable metric that varies across the brain along interpretable lines of anatomical difference. We also parcellate white matter into ``crystal grains," or contiguous sets of voxels of high structural similarity, and find overlap with other white matter parcellations. Our results provide new means of assessing white matter microstructure on multiple length scales, and open new avenues of future inquiry.

Resonance is defined as a maximal amplification of the response of a system to periodic inputs in a limited, intermediate input frequency band. Resonance may serve to optimize inter-neuronal communication, and has been observed at multiple levels of neuronal organization including membrane potential fluctuations, single neuron spiking, postsynaptic potentials, and neuronal networks. However, it is unknown how resonance observed at one level of neuronal organization (e.g., network) depends on the properties of the constituting building blocks, and whether, and if yes how, it affects the resonant and oscillatory properties upstream. One difficulty is the absence of a conceptual framework that facilitates the interrogation of resonant neuronal circuits and organizes the mechanistic investigation of network resonance in terms of the circuit components, across levels of organization. We address these issues by discussing a number of representative case studies. The dynamic mechanisms responsible for the generation of resonance involve disparate processes, including negative feedback effects, history-dependence, spiking discretization combined with subthreshold passive dynamics, combinations of these, and resonance inheritance from lower levels of organization. The band-pass filters associated with the observed resonances are generated by primarily nonlinear interactions of low- and high-pass filters. We identify these filters (and interactions) and we argue that these are the constitutive building blocks of a resonance framework. Finally, we discuss alternative frameworks and we show that different types of models (e.g., spiking neural networks and rate models) can show the same type of resonance by qualitative different mechanisms.

Even if major depression is now the most common of psychiatric disorders, successful antidepressant treatments are still difficult to achieve. Therefore, a better understanding of the mechanisms of action of current antidepressant treatments is needed to ultimately identify new targets and enhance beneficial effects. Given the intimate relationships between astrocytes and neurons at synapses and the ability of astrocytes to "sense" neuronal communication and release gliotransmitters, an attractive hypothesis is emerging stating that the effects of antidepressants on brain function could be, at least in part, modulated by direct influences of astrocytes on neuronal networks. We will present two preclinical studies revealing a permissive role of glia in the antidepressant response: i) Control of the antidepressant-like effects of rat prefrontal cortex Deep Brain Stimulation (DBS) by astroglia, ii) Modulation of antidepressant efficacy of Bright Light Stimulation (BLS) by lateral habenula astroglia. Therefore, it is proposed that an unaltered neuronal-glial system constitutes a major prerequisite to optimize antidepressant efficacy of DBS or BLS. Collectively, these results pave also the way to the development of safer and more effective antidepressant strategies.

Join us to hear about degrees and careers in neuroscience, what it’s like to be a neuroscientist, the wide range of career options open to you after a neuroscience degree, first-hand examples of career paths in neuroscience, and some tips and thoughts to help you in your own careers. This free and friendly webinar will give you the chance to ask questions from people with different experiences in neuroscience: - Emma Soopramanien, the BNA Committee Representative for Students and Early Career Researchers – Emma has just completed her undergraduate course in neuroscience, and will be hosting the webinar. - Professor Anthony Isles, BNA Trustee – Anthony is a professor at Cardiff University, where he researches epigenetic mechanisms of brain and behaviour and how they contribute to neurodevelopmental and neuropsychiatric disorders, as well as teaching undergraduate and postgraduate students. He will talk about how he came to be a neuroscientist researcher and ways into neuroscience. - Dr Anne Cooke, BNA Chief Executive – Anne studied physiology and neuroscience at university and carried out research into neuronal communication, before then following a career path with roles in academia and industry, and now as CE at the BNA. Anne will describe her own career in neuroscience, as well as some of the many other options open to you after a neuroscience degree.