  We study Betti structures in the solution complexes of confluent
hypergeometric equations. We use the framework of enhanced ind-sheaves and the
irregular Riemann-Hilbert correspondence of D'Agnolo-Kashiwara. The main result
is a group theoretic criterion that ensures that enhanced solutions of such
systems are defined over certain subfields of the complex numbers. The proof
uses a description of the hypergeometric systems as exponentially twisted
Gauss-Manin systems of certain Laurent polynomials.
