Implicit learning of sequential regularities and spatial contexts in corticobasal syndrome.

The present study investigated two forms of implicit learning in patients with corticobasal syndrome (CBS): contextual cueing and sequence learning. The former primarily implicates the medial temporal lobe system, and the latter, fronto-striatal-cerebellar circuits. Results revealed relatively preserved contextual cueing in patients with CBS. By contrast, sequence learning showed impairments, which seemed to reflect inability to execute correct responses in the presence of intact learning of the sequence. These findings provide the first characterization of implicit learning systems in CBS, and show that the two systems are differentially affected in patients with CBS.