Dear Colleagues, * * we are pleased to announce the workshop "*Enabling synaptic plasticity, structural plasticity, and multi-scale modeling with morphologically detailed neurons using Arbor*", which will take place at *CNS*2025* on *Wednesday, 9 July*, in Florence, Italy. Current computational neuroscience studies are often limited to a single scale or simulator, with many still relying on standalone simulation code due to computational power and technology constraints. Simulations incorporating biophysical properties and neural morphology typically focus on single neurons or small networks, while large-scale neural network simulations often resort to point neurons as a compromise to incorporate plasticity and cell diversity. Whole-brain simulations, on the other hand, frequently sacrifice details at the individual neuron and network composition levels. This workshop introduces recent advances leveraging the next-generation simulator Arbor (https://arbor-sim.org/), designed to overcome these challenges. Arbor enables seamless conversion from the widely used NEURON simulator, facilitates the study of functional and structural plasticity in large neural networks with detailed morphology, and supports multi-scale modeling through co-simulation, integrating microscopic and macroscopic levels of simulation. Arbor is a library optimized for efficient, scalable neural simulations by utilizing both GPU and CPU resources. It supports the simulation of both individual neurons and large-scale networks while maintaining detailed biophysical properties and morphological complexity. The workshop will feature presentations covering three key aspects: * *Effortless transition from NEURON to Arbor:* Beatriz Herrera will introduce the SONATA format, which simplifies the migration process and enables cross-simulator validation, ensuring a smooth transition to Arbor for researchers familiar with NEURON. * *Plasticity simulations with Arbor:* In two talks, Jannik Luboeinski and Felix Wolf will present Arbor’s capabilities in modeling calcium-based functional plasticity as well as calcium-based distance-dependent structural plasticity, providing insights into synaptic and structural changes. * *Multi-scale co-simulation with TVB:* Thanos Manos will demonstrate Arbor’s co-simulation capabilities with The Virtual Brain (TVB) platform, illustrating the study of epilepsy propagation as an example of multi-scale modeling. The workshop will conclude with an *interactive coding session*, offering participants hands-on experience with Arbor and an opportunity to apply the presented concepts. We look forward to meeting you at the workshop, where we expect fruitful exchange and interesting discussions! Best regards, Thorsten Hater, Han Lu, Jannik Luboeinski