This work tests the hypothesis that the cerebellum is critical to the perception of the timing of sensory events. Auditory tasks were used to assess two types of timing in a group of patients with a stereotyped specific degeneration of the cerebellum: the analysis of single time intervals requiring absolute measurements of time, and the holistic analysis of rhythmic patterns based on relative measures of time using an underlying regular beat. The data support a specific role for the cerebellum only in the absolute timing of single subsecond intervals but not in the relative timing of rhythmic sequences with a regular beat. The findings support the existence of a stopwatch-like cerebellar timing mechanism for absolute intervals that is distinct from mechanisms for entrainment with a regular beat.T he relevance of the human cerebellum to the perception of time intervals and rhythmic sequences is controversial. Involvement of the cerebellum in perceptual timing (the perception of the timing of sensory events), in addition to its role in motor timing (the timed execution of movements), has been suggested by a number of studies (1-6). One distinction that we wish to address here, which has not been made clear in previous work, is between the absolute, duration-based timing of single subsecond intervals and the relative timing of subsecond intervals based on a regular beat. Functional imaging studies suggest neural activity in the human cerebellum during the perception of the absolute duration of single time intervals (7,8) as well as rhythmic patterns with a regular beat (9-13). However, previous lesion work to assess an obligatory cerebellar role in the perception of single time intervals has not yielded consistent results (4,(14)(15)(16)(17). Previous lesion work to assess any obligatory role of the cerebellum in the analysis of rhythmic sequences has assessed only deficits in related motor activity, such as tapping out a beat (4,14,18), that do not allow clear inference about perception.In this study, we test whether the cerebellum is a critical substrate for perceptual tasks that require the absolute, durationbased analysis of single time intervals as well as those that require the relative analysis of time intervals within rhythmic patterns based on a regular beat. Perceptual tests were conducted in the auditory domain, where accurate temporal encoding of sensory events is essential and entrainment with a beat is induced naturally. Tasks were administered to a group of 34 patients with a stereotyped cerebellar degeneration and a matched control group of 40 healthy individuals. Two absolute timing tasks tested the perception of single intervals for a variable and a fixed reference duration, respectively ( Fig. 1 A and B). Three relative timing tasks tested the beat-based analysis of rhythmic sequences, including the detection of the presence of a roughly regular beat (19), a deviation from an isochronous beat (20) and a distortion of a rhythmic pattern with a metrical beat (21) (Fig. 1 C-E). The data support a ce...

This work tests the relationship between auditory and phonological skill in a non-selected cohort of 238 school students (age 11) with the specific hypothesis that sound-sequence analysis would be more relevant to phonological skill than the analysis of basic, single sounds. Auditory processing was assessed across the domains of pitch, time and timbre; a combination of six standard tests of literacy and language ability was used to assess phonological skill. A significant correlation between general auditory and phonological skill was demonstrated, plus a significant, specific correlation between measures of phonological skill and the auditory analysis of short sequences in pitch and time. The data support a limited but significant link between auditory and phonological ability with a specific role for sound-sequence analysis, and provide a possible new focus for auditory training strategies to aid language development in early adolescence.

A role for the cerebellum in cognition has been proposed based on studies suggesting a profile of cognitive deficits due to cerebellar stroke. Such studies are limited in the determination of the detailed organisation of cerebellar subregions that are critical for different aspects of cognition. In this study we examined the correlation between cognitive performance and cerebellar integrity in a specific degeneration of the cerebellar cortex: Spinocerebellar Ataxia type 6 (SCA6). The results demonstrate a critical relationship between verbal working memory and grey matter density in superior (bilateral lobules VI and crus I of lobule VII) and inferior (bilateral lobules VIIIa and VIIIb, and right lobule IX) parts of the cerebellum. We demonstrate that distinct cerebellar regions subserve different components of the prevalent psychological model for verbal working memory based on a phonological loop. The work confirms the involvement of the cerebellum in verbal working memory and defines specific subsystems for this within the cerebellum.

This work tests the hypothesis that language skill depends on the ability to incorporate streams of sound into an accurate temporal framework. We tested the ability of young English-speaking adults to process single time intervals and rhythmic sequences of such intervals, hypothesized to be relevant to the analysis of the temporal structure of language. The data implicate a specific role for the ability to process beat-based temporal regularities in phonological language and literacy skill.

This study sought evidence for a specific cerebellar contribution to cognition by characterising the cognitive phenotype of Spinocerebellar Ataxia Type 6 (SCA-6); an autosomal dominant genetic disease which causes a highly specific late-onset cerebellar degeneration. A comprehensive neuropsychological assessment was administered to 27 patients with genetically confirmed SCA-6. General intellectual ability, memory and executive function were examined using internationally standardised tests (Wechsler Adult Intelligence Scale-III, Wechsler Memory Scale-III, Delis and Kaplan Executive Function System, Brixton Spatial Anticipation test). The patient group showed no evidence of intellectual or memory decline. However, tests of executive function involving skills of cognitive flexibility, inhibition of response and verbal reasoning and abstraction demonstrated significant impairment at the group level with large effect sizes. The results demonstrate an executive deficit due to SCA-6 that can be conceptualised as parallel to the motor difficulties suffered by these patients: the data support a role for the cerebellum in the regulation and coordination of cognitive, as well as motor processes that is relevant to individual performance.