When time is up: CNV time course differentiates the roles of the hemispheres in the discrimination of short tone durations

Richard Ragot, Micha Pfeuty, Viviane Pouthas
Experimental Brain Research. 2003-08-01; 151(3): 372-379
DOI: 10.1007/s00221-003-1505-6

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Pfeuty M(1), Ragot R, Pouthas V.

Author information:
(1)Neurosciences Cognitives et Imagerie Cérébrale, LENA-CNRS, Hôpital
Salpêtrière, 47 Bd de l’Hôpital, 75651 Paris, France.

Numerous studies have suggested that the CNV (contingent negative variation), a
negative slow wave developing between a warning and an imperative stimulus,
reflects, among other things, temporal processing of the interval between these
two stimuli. One aim of the present work was to specify the relationship between
CNV activity and the perceived duration. A second aim was to establish if this
relationship is the same over the left and right hemispheres. Event-related
potentials (ERPs) were recorded for 12 subjects performing a matching-to-sample
task in which they had to determine if the duration of a tone (490 ms, 595 ms,
700 ms, 805 ms, and 910 ms) matched that of a previously presented standard (700
ms). CNV activity measured at the FCZ electrode was shown to increase until the
standard duration had elapsed. By contrast, right frontal activity increased
until the end of the current test duration, even when the standard duration had
elapsed. Moreover, for long test durations (805 ms and 910 ms), correlations
were observed between CNV peak latency and subjective standard, over left and
medial frontal sites. We propose that left and medial frontal activity reflects
an accumulation of temporal information that stops once the memorized standard
duration is over, while right frontal activity subserves anticipatory attention
near the end of the stimulus.