library_construction_protocol: The brain samples and/or bio samples were obtained from The Netherlands Brain Bank, Netherlands Institute for Neuroscience, Amsterdam (open access: www.brainbank.nl). All Material has been collected from donors for or from whom a written informed consent for a brain autopsy and the use of the material and clinical information for research purposes had been obtained by the NBB. Additional samples were provided by the Queen Square Brain Bank of Neurological Disorders and MRC, King College London. We complied to all relevant regulations of the mentioned brain banks for the work with these samples. Total RNA for smRNA-seq was isolated from frozen tissue using the TRIzol reagent (ThermoFischer Scientific). After isopropanol precipitation and 80% ethanol rinsing RNA pellet was resuspended in RNAse free water and up to 10 micrograms of RNA was incubated with 2U of Ambion DNAse I (ThermoFischer) at 37°C for 20 minutes.  DNA-free RNA samples were then further purified by phenol-chloroform-isoamyl-alchol extraction followed by ethanol precipitation.   The small RNA-seq libraries were prepared in two different batches. They were prepared from frozen tissue starting from 2 micrograms of total RNA using the Nextflex Small RNA-seq kit v3 (Bioo Scientific, batch2) and the NEBNext Small RNA library prep set for Illumina (New England Biolabs, batch1), respectively.