Effects of divided attention on temporal processing in patients with lesions of the cerebellum or frontal lobe

Prefrontal cortex and cerebellum have both been implicated in temporal proc essing tasks although the exact contribution of each system remains unclear . To investigate this issue, control participants and patients with either prefrontal or cerebellar lesions were tested on temporal and nontemporal pe rceptual tasks under 2 levels of attentional load. Each trial involved a co mparison between a standard tone and a subsequent comparison tone that vari ed in frequency, duration, or both. When participants had to make concurren t judgments on both dimensions, patients with frontal lobe lesions were sig nificantly impaired on both tasks whereas the variability of cerebellar pat ients increased in the duration task only. This dissociation suggests that deficits on temporal processing tasks observed in frontal patients can be r elated to the attention demands of such tasks; cerebellar patients have a m ore specific problem related to timing.