Cerebellum and procedural learning: evidence from focal cerebellar lesions

TLDR

The study investigates how focal cerebellar lesions affect procedural learning. Eight patients with cerebellar lesions and six controls performed a four‑choice serial reaction‑time task with repeated sequences, measuring latency reductions and declarative sequence knowledge. Patients with cerebellar lesions showed impaired procedural learning, with slower reaction times and difficulty detecting and repeating sequences, whereas pre‑learning of the sequence improved motor performance in all participants.

Abstract

The aim of the present study was to investigate the influence of focal cerebellar lesions on procedural learning. Eight patients with cerebellar lesions and six control subjects were tested in a serial reaction-time task. A four-choice reaction-time task was employed in which the stimuli followed (or not) a sequence repeated 10 times, with the subjects aware (or not) of the item sequence. Learning was manifested by the reduction in response latency over the sequential blocks. Acquisition of declarative knowledge of the sequence was also tested. Reaction times displayed by patients with cerebellar lesions, even though they tended to be longer than those of control subjects in all testing conditions, significantly differed from control subjects only when the stimuli were presented in sequence. The reaction times in sequential trials were still statistically significant when simple motor response times were taken into account. Cerebellar patients were also significantly impaired in detecting and repeating the sequence. On the other hand, when the sequence was learned before testing, motor performances were significantly improved in all subjects. These data indicate that cerebellar lesions induce specific impairment in the procedural learning of a motor sequence and suggest a role of the cerebellar circuitry in detecting and recognizing event sequences.