Johan Medrano contributed to the spm/spm and spm/spm-docs repositories by developing new MATLAB scripts and enhancing documentation to support neuroimaging research workflows. He introduced demonstration experiments for Dynamic Causal Modeling, simulating time-varying effective connectivity in CSD and ERP data, and updated analysis pipelines to include synaptic plasticity metrics. Johan improved onboarding and reproducibility by reorganizing documentation and clarifying dependencies. He also enhanced ERP processing by adding robust channel indexing and refactored plotting code for compatibility across MATLAB versions. His work combined MATLAB scripting, data simulation, and signal processing, demonstrating depth in both technical implementation and research-oriented problem solving.