  We made a link between Extra Cellular Matrix (ECM) plasticity and the
morphologi cal changes in synapses after synaptic excitation. A recent study by
Zhang et al \cite{zhang} showed tha t transmembrane voltage causes movement of
the cell membrane. Here we will study the relation between th e mechanical
properties of collagen which is the major component of the ECM and synaptic
morphological c hanges in relation with the theory of DO Hebb \cite{hebb}
