Aggregation-induced emission: An illuminator in the brain

•Penetration of AIEgen-based nanomaterials across biological barriers were summarized.•Detection and diagnosis of brain diseases with AIEgens were summarized.•Bioimaging of the brain structure in health and disease were summarized.•Therapeutics for specific diseases in the brain using AIEgens were summarized.•Future outlooks surrounding the applications of AIEgens in the brain were summarized.