  In this paper we study a linear inverse problem with a biological
interpretation, which is modeled by a Fredholm integral equation of the first
kind. When the kernel in the Fredholm equation is represented by step func-
tions, we obtain identifiability, stability and reconstruction results.
Further- more, we provide a numerical reconstruction algorithm for the kernel,
whose main feature is that a non-regular mesh has to be used to ensure the
invert- ibility of the matrix representing the numerical discretization of the
system. Finally, a second identifiability result for a polynomial approximation
of degree less than nine of the kernel is also established.
