This is a model and a simulator (ernst) associated with the publication: Mihalas S, Dong Y, von der Heydt R, Niebur E, Krieger Z (2011) Event-related simulation of neural processing in complex visual scenes Information Sciences and Systems (CISS), 2011 45th Annual Conference 45:1-6 Abstract: Understanding the neural processing of complex visual scenes is facilitated by tools that allow efficient simulation of large neural systems. We here present an environment for the implementation of large networks of generalized integrate-andfire neurons which uses an asynchronous event-based algorithm. It allows accurate (up to machine precision) calculation of neuronal spike times. Its efficiency arises from its ability to solve the subthreshold dynamics of the model analytically. The simulator is implemented in JAVA and it can run in parallel on a large number of computers with different architectures without the need for compilation. The neuronal network to be simulated and all parameters are defined in extendible markup language. A model of the primate early visual system is implemented. The use of the tool is illustrated by simulating the processing of both simple and complex visual scenes through retina, thalamus and primary visual cortex. http://ernst.mb.jhu.edu/ is a web-link to a network model and simulator (ernst) developed by Ernst Niebur's group at Johns Hopkins. Usage instructions are provided in the readme from the ernst-version.tgz file available from the ernst.mb.jhu.edu website's download button. Follow the first link above to find the model (fullmodel.xml in model folder).