BDNF and spinocerebellar ataxia type 6: Similarly, the BDNF intensity was decreased in all three cerebellar cortical layers of pre-onset SCA684Q/84Q mice (a mouse model of SCA6), and the oral administration of a TrkB agonist, 7,8-DHF, before disease onset improved the rotarod performance and elevated the PC firing frequency in these mice [10].