We provide evidence of the relation between supersymmetric gauge theories and matrix models beyond the planar limit. We compute gravitational $R^2$ couplings in gauge theories perturbatively, by summing genus one matrix model diagrams. These diagrams give the leading $1/N^2$ corrections in the large $N$ limit of the matrix model and can be related to twist field correlators in a collective conformal field theory. In the case of softly broken $SU(N)\ \cN=2$ super Yang-Mills theories, we find that these exact solutions of the matrix models agree with results obtained by topological field theory methods.
"Matrix Models and Gravitational Corrections." Adv. Theor. Math. Phys. 7 (6) 1155 - 1174, December, 2003.