Let k be a field of characteristic zero. Let /: ->• be a proper and smooth morphism of non-singular algebraic Â:-varieties. If k c= C, let / : X -»• S be the analytic morphism associated to /, then the cohomology groups of the fibers, H^X^, C), seS, form a complex local System over S, which is the System of local solutions of the Gauss-Manin connection. By results of Fuchs, Grothendieck, Griffiths,..., it is known that this connection has relevant properties: it is defined over k, has regular singular points, its exponents are rational and it supports a variation of Hodge structures. The rational homotopy of the fibers of/aiso gives other important complex local Systems over S. The aim of this article consists in proving that the holomorphic connections associated to every local System that cornes frorn the rational homotopy of the fibers hâve the same algebraic properties than the connections coming from the cohomology.