This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 898052.

Know HESSP'S mission

LThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 898052.

Our Mission

Understanding the human brain is one of the biggest scientific challenges. Until now, one aspect that that has been sparsely researched is the extracellular space (ES) of the brain. The ES of the brain is important in the field of neuropharmacology because it is key to the successful delivery of drugs. Also, the importance of the metabolite clearance activity of the ES has led to considering its role in neurodegenerative diseases. To help in the understanding of the ES, the Hippocampus Extracellular Space Simulator Project (HESSP) is going to be executed. The EU-funded HESSP project goal is to develop a software that simulates the diffusion process of endogenous and exogenous substances in the ES of the mouse’s hippocampus.


The advent of computers has led to widespread use of the iterative paradigm because an iterative process can be executed quickly; however, this technique is bound by technological limitations. Some simulations are impossible because they are beyond our computational resource limits. For example, if one wants to simulate a 1 mg. dose of a benzodiazepine in the brain, memory resource is a problem. It requires almost 29 million Terabytes if the position of each molecule is required to be known for each step of the simulation.

The Hippocampus Extracellular Space Simulator Project (HESSP) proposes a hybrid tiered architecture of two levels to carry out an iterative simulation of a relevant number of molecules over functional distances for basic and clinical research. In the first level, the program would make a physical iterative simulation of each molecule. In the second level, the program would use the data generated in the first level to simulate statistically the diffusion of molecules. The HESSP started in September 2020. Its goal is to design and test an iterative hybrid multilevel architecture of simulation that can overcome the technological limitations of direct simulation to simulate the hippocampus extracellular space.

Two simulation paradigms

Two possible paradigms exist for simulating a system according to the role parameter time plays from a mathematical point of view: equational and iterative. In the equational parameter, time is a parameter of a function's domain. In the iterative paradigm, time is the number of times a function must be iterated to achieve the system's state at the moment of interest.

Simulating diffusion in a complex environment using the equational approach is problematic because it requires building a function that describes the geometry of the environment to formulate the differential equation. The mathematical difficulty of that task forces us to look at the iterative paradigm.