Biomedical subjects

Henning Gibbons

Publications and source records attributed to Henning Gibbons.

5 recordsLinked to original sources

PubMed2005

Electrophysiological correlates of temporal generalization: evidence for a two-process model of time perception.

In an event-related potential (ERP) study, brain correlates of temporal processing in the range of milliseconds were investigated by means of a dissociation paradigm. For this purpose, ten male and ten female subjects performed temporal and pitch generalization tasks with uni- and bidimensional stimulus variation. With difficulty held constant for both tasks, a larger frontally distributed negative slow wave was observed for pitch generalization relative to temporal generalization. This ERP pattern was consistent across uni- and bidimensional tasks of the present study but in direct contrast to prior ERP studies on temporal processing. Furthermore, for both uni- and bidimensional temporal tasks, within-task ERP analyses yielded amplitude modulation of centro-parietal P3b and fronto-central P500 as brain correlates of actively processed stimulus duration. Findings were consistent with a two-process model of temporal information processing based on a real-time comparison of the presented stimulus duration against an internal representation of the standard duration.

Adult↗

PubMed2004

Differential effects of prime-probe duration on positive and negative location priming: Evidence for opponent facilitatory and inhibitory influences in priming tasks.

A series of four spatial localization experiments is reported that examined the effects of display duration and presentation mode on positive and negative priming using an attended-repetition and an ignored-repetition paradigm, respectively. Experiment 1 showed larger positive priming with response-dependent than with 150 ms display durations while negative priming remained unaffected. Experiments 2-4 were performed to further elucidate the effects of prime-probe durations. Data suggest largely independent effects of prime and probe duration on priming effects. Manipulation of prime duration affected facilitation due to repetition of the prime distractor location as well as inhibitory effects associated with ignored repetition. Furthermore, anticipated probe duration modulated the effectiveness of inhibition of return. Findings are discussed within a framework proposing two major components of priming effects--a stimulus-driven or automatic component, and a strategic component related to the participant's expectations towards the probe.

Adult↗

PubMed2004

The application of jackknife-based onset detection of lateralized readiness potential in correlative approaches.

The onset of the lateralized readiness potential (LRP) represents an interesting parameter within mental chronometry. According to Miller, Patterson, and Ulrich (1998), reliability increases when LRP onsets are detected in jackknifed LRP waveforms. Until now, jackknifed LRP onsets could be analyzed in factorial designs only. The aim of the present study was to extend the application of jackknifing to correlative approaches (e.g., in personality research). Using different onset scoring techniques, in several simulations run on realistic LRP data jackknifing and single-subject procedures were compared regarding their estimates of a simulated true correlation. For all scoring techniques but regression, jackknifed coefficients were on average higher than the respective single-subject coefficients, and statistical power was higher. Overall, combining jackknifing with a 50%-relative onset criterion is recommended.

Algorithms↗

PubMed2004

Current-source density analysis of slow brain potentials during time estimation.

Two event-related potential studies were conducted to investigate differential brain correlates of temporal processing of intervals below and above 3-4 s. In the first experiment, 24 participants were presented with auditorily marked target durations of 2, 4, and 6 s that had to be reproduced. Timing accuracy was similar for all three target durations. As revealed by current-source density analysis, slow-wave components during both presentation and reproduction were independent of target duration. Experiment 2 examined potential modulating effects of type of interval (filled and empty) and presentation mode (randomized and blocked presentation of target durations). Behavioral and slow-wave findings were consistent with those of Experiment 1. Thus, the present findings support the notion of a general timing mechanism irrespective of interval duration as proposed by scalar timing theory and pacemaker-counter models of time estimation.

Acoustic Stimulation↗

PubMedDate not supplied

Dissociating aspects of temporal and frequency processing: a functional ERP study in humans.

An event-related potential (ERP) study was conducted, in order to dissociate brain functions associated with temporal information processing and processing of frequency information. Twelve participants were presented with both a temporal generalization and a pitch generalization task. In both tasks, exactly the same set of stimuli was presented to prevent stimulus-specific influences on ERP patterns. Participants had to decide whether or not an auditory stimulus matched a previously memorized standard stimulus, either with respect to pitch or duration. Analysis of ERPs revealed an increased negativity for the temporal discrimination task at fronto/central electrode sites. This effect was observed between 150 msec and 1,000 msec. At posterior sites, however, there was an increased positivity between 500 and 1,000 msec for the temporal generalization task. The differential topological activation patterns suggest more pronounced utilization of executive working-memory ressources for processing of temporal than for processing of pitch information.

Adult↗