Shape analysis of 3D nanoscale reconstructions of brain cell nuclear envelopes by implicit and explicit parametric representations

•We introduce a framework for analyzing 3D nanoscale reconstructions of nuclei of brain cells.•Shapes are obtained by semiautomatic segmentation of electron micrographs.•The framework considers implicit and explicit parametric representations.•The implicit parameterization is derived from hyperquadrics formulation.•The explicit parametrization is derived from spherical harmonics decomposition.