The present invention relates to a heterocyclic derivative according to formula I wherein the variables are defined as in the specification, or to a pharmaceutically acceptable salt or solvate thereof. The present invention also relates to a pharmaceutical composition comprising said heterocyclic derivatives and to their use in therapy, for instance in the treatment or prevention of psychiatric diseases where an enhancement of synaptic responses mediated by AMPA receptors is required, including schizophrenia, depression and learning and memory disorders such as Alzheimer's disease.