The invention relates, inter alia, to the use of neuregulin-β as a target in a screening method for active compounds, in particular for exerting an influence on changes in calcium concentration which are mediated by glutamate receptors. The invention furthermore relates to the use of neuregulins, preferably a neuregulin isoform having an isoelectric point in the range from pH 4.3 to 5.0, as a target for detecting and/or exerting an influence on neuronal processes, in particular for exerting an influence on long-term memory. Neuregulins, in particular neuregulin-.beta. and also substances which exert an influence on the status, i.e. the expression and/or post -translational modification, of neuregulin-.beta., can therefore be used as agents for controlling the course of, treating and/or alleviating neuronal diseases, e.g. Alzheimer's disease.