The current project aims to implement the option to carry out the numerical integration part in the Brian simulator with integrators defined in external libraries, starting with the odeiv2 module that comes with the GNU Scientific Library (GSL). In addition to coming with an extensive list of different integration methods, the GSL integrator comes with an adaptable timestep. The latter functionality will have major benefits for the speed with which large simulations in Brian can run. This is because it allows the use of larger timesteps for the overhead loops in Python, without losing (likely even improving) the accuracy of the numerical integration at points where small timesteps are necessary. I have personally used Brian, and can tell from experience that this can be very useful at times - especially when working with Hodgkin-Huxley-type equations. I think this speed-up could be an important factor for people to choose to use Brian for their simulations.