Type IIB superstring brane configurations can have a low energy dynamics described by an effective 3d N=4 gauge theory. The moduli space of the gauge theory is normally a Hyperkähler variety. Singular points in the variety correspond to brane configurations where some fields become massless, giving rise to the Higgs mechanism. I will explain the relevance of a set of theories whose moduli space is the closure of a nilpotent orbit of Lie(F), where F is the flavour symmetry group of the theory. I will show how the mathematical description of the "transverse slice" between two nilpotent orbits can be understood in terms of brane dynamics as a realisation of the Higgs mechanism.