This is the readme for the model associated with the paper Bruce A. Carlson and Masashi Kawasaki (2006) Ambiguous Encoding of Stimuli by Primary Sensory Afferents Causes a Lack of Independence in the Perception of Multiple Stimulus Attributes J Neurosci 26(36):9173-9183 Abstract: Accurate sensory perception often depends on the independent encoding and subsequent integration of multiple stimulus attributes. In the weakly electric fish Eigenmannia, P- and T-type primary afferent fibers are specialized for encoding the amplitude and phase, respectively, of electrosensory stimuli. We used a stimulus estimation technique to quantify the ability of P- and T-units to encode random modulations in amplitude and phase. As expected, P-units exhibited a clear preference for encoding amplitude modulations, whereas T-units exhibited a clear preference for encoding phase modulations. Surprisingly, both types of afferents also encoded their nonpreferred stimulus attribute when it was presented in isolation or when the preferred stimulus attribute was sufficiently weak. Because afferent activity can be affected by modulations in either amplitude or phase, it is not possible to unambiguously distinguish between these two stimulus attributes by observing the activity of a single afferent fiber. Simple model neurons with a preference for encoding either amplitude or phase also encoded their nonpreferred stimulus attributewhenit was presented in isolation, suggesting that such ambiguity is unavoidable. Using the well known jamming avoidance response as a probe of electrosensory perception, we show that the ambiguity at the single-neuron level gives rise to a systematic misrepresentation of stimuli at the population level and a resulting misperception of the amplitude and phase of electrosensory stimuli. Usage notes: The archive has all the Matlab and Simulink files needed to run the leaky integrate-and-fire models from our J Neurosci paper. To run the models, the user should type "PrimAff_IntFire" at the Matlab command prompt. This will open a GUI that allows the user to set the parameters of the model, run the simulation, and plot the resulting spike train and stimulus. The option to "View Simulation in Action", when checked, runs the simulation in Simulink, so that the user can actually watch the simulation on an oscilloscope, rather than just receive the output of the simulation. The Matlab model is "liandfrn.m", the Simulink version uses "liandfrn_sim.m" and "PrimAff.mdl". "genstim.m" is a script for generating the stimulus, "modsine.m" is a function for generating sinusoidal stimulus modulations, and "blim_whnoise.m" is a function for generating random stimulus modulations.