Biomedical subjects

Micha Pfeuty

Publications and source records attributed to Micha Pfeuty.

4 recordsLinked to original sources

PubMed2005

Relationship between CNV and timing of an upcoming event.

This study reports an analysis of the Contingent Negative Variation (CNV) recorded on the human scalp during the comparison of a test duration with a previously memorized duration. Results show that CNV activity peaks at the end of the memorized duration, and that its slope varies inversely with the length of this duration. These features of CNV activity are similar to those of climbing neuronal activity observed through intracerebral recordings in animals, and suggest that both activities reflect how the brain encodes the timing of an upcoming event. These results also show that the time-course of the CNV in timing tasks is compatible with a pacemaker-accumulator model of temporal processing.

Acoustic Stimulation↗

PubMed2005

Neural network involved in time perception: an fMRI study comparing long and short interval estimation.

In this study, long ( approximately 1,300 ms) and short duration ( approximately 450 ms) estimation trials in an event-related functional MRI (fMRI) study were contrasted in order to reveal the regions within a time estimation network yielding increased activation with the increase of the duration to be estimated. In accordance with numerous imaging studies, our results showed that the presupplementary motor area (preSMA), the anterior cingulate, the prefrontal and parietal cortices, and the basal ganglia were involved in the estimation trials whatever the duration to be estimated. Moreover, only a subset of the regions within this distributed cortical and subcortical network yielded increased activation with increasing time, namely, the preSMA, the anterior cingulate cortex, the right inferior frontal gyrus (homolog to Broca's area), the bilateral premotor cortex, and the right caudate nucleus. This suggests that these regions are directly involved in duration estimation. We propose that the caudate-preSMA circuit, the anterior cingulate, and the premotor-inferior frontal regions may support a clock mechanism, decision and response-related processes, and active maintenance of temporal information, respectively.

Adult↗

PubMed2003

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

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.

Adolescent↗

PubMed2003

Processes involved in tempo perception: a CNV analysis.

The purpose of this research was to study the mechanisms underlying tempo perception, by looking at their electrophysiological brain correlates. The subjects' task consisted of comparing the tempos of two isochronous tone sequences made up of either three (condition 13) or six (condition 16) 600-ms intervals. Contingent negative variation (CNV), known to be linked to the judgment of a single interval, kept increasing in amplitude for three intervals during tempo encoding, thereby providing evidence of the occurrence of CNVs also for several intervals in succession. This CNV increase could reflect the use of interval-based processes in the building of the interval memory trace. During the comparison phase, a CNV decrease was observed in condition 16, suggesting that subjects did not build a new memory trace, but used beat-based processes to check whether the beats of the new tempo occurred at the times they anticipated.

Acoustic Stimulation↗