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Martin Guessmann

Publications and source records attributed to Martin Guessmann.

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Synergetic Analysis of the Haeussler-von der Malsburg Equations for Manifolds of Arbitrary Geometry

We generalize a model of Haeussler and von der Malsburg which describes the self-organized generation of retinotopic projections between two one-dimensional discrete cell arrays on the basis of cooperative and competitive interactions of the individual synaptic contacts. Our generalized model is independent of the special geometry of the cell arrays and describes the temporal evolution of the connection weights between cells on different manifolds. By linearizing the equations of evolution around the stationary uniform state we determine the critical global growth rate for synapses onto the tectum where an instability arises. Within a nonlinear analysis we use then the methods of synergetics to adiabatically eliminate the stable modes near the instability. The resulting order parameter equations describe the emergence of retinotopic projections from initially undifferentiated mappings independent of dimension and geometry.

physics.bio-ph

Solutions of the Haeussler-von der Malsburg Equations in Manifolds with Constant Curvatures

We apply generic order parameter equations for the emergence of retinotopy between manifolds of different geometry to one- and two-dimensional Euclidean and spherical manifolds. To this end we elaborate both a linear and a nonlinear synergetic analysis which results in order parameter equations for the dynamics of connection weights between two cell sheets. Our results for strings are analogous to those for discrete linear chains obtained previously by Haeussler and von der Malsburg. The case of planes turns out to be more involved as the two dimensions do not decouple in a trivial way. However, superimposing two modes under suitable conditions provides a state with a pronounced retinotopic character. In the case of spherical manifolds we show that the order parameter equations provide stable stationary solutions which correspond to retinotopic modes. A further analysis of higher modes furnishes proof that our model describes the emergence of a perfect one-to-one retinotopy between two spheres.

physics.bio-ph