The invention relates, inter alia, to the use of neuregulin-β as an indicator in a method for detecting a neuronal process. 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-β and also substances which exert an influence on the status, i.e. the expression and/or post-translational modification, of neuregulin-β, can therefore be used as agents for controlling the course of, treating and/or alleviating neuronal diseases, e.g. Alzheimer's disease.