Biomedical subjects

Jutta Stahl

Publications and source records attributed to Jutta Stahl.

9 recordsLinked to original sources

PubMed2006

Dynamics of response-conflict monitoring and individual differences in response control and behavioral control: an electrophysiological investigation using a stop-signal task.

OBJECTIVES: The aim of the present study was to investigate the functional significance of error (related) negativity Ne/ERN and individual differences in human action monitoring. A response-conflict model of Ne/ERN should be tested applying a stop-signal paradigm. After a few modifications of Ne/ERN response-conflict theory (Yeung N, Botvinick MM, Cohen JD. The neural basis of error detection: conflict monitoring and the error-related negativity. Psychological Review 2004:111(4);931-959), strength and time course of response conflict could be modeled as a function of stop-signal delay. METHOD: In Experiment 1, 35 participants performed a visual two-choice response-time task but tried to withhold the response if an auditory stop signal was presented. Probability of stopping errors was held at 50% using variable delays between visual and auditory stimuli. Experiment 2 (n=10) employed both auditory go and stop signals and confirmed that Ne/ERN effects are due to conflict induced by the auditory stop signal, and not the mere presence or absence of an additional stimulus. RESULTS: As predicted, amplitudes of both the stimulus-locked and response-locked Ne/ERN were largest for non-stopped responses, followed by successfully stopped and go responses. However, independently of response type Ne/ERN also increased with increasing stop-signal delay. Since longer delay invokes stronger response conflict, results specifically support the notion of Ne/ERN reflecting response-conflict monitoring. Furthermore, individual differences related to measures of response control and behavioral control were observed. Both low response control estimated from stop-task performance and high psychometric impulsivity were accompanied by smaller Ne/ERN amplitude on stop trials, suggesting reduced response-conflict monitoring. CONCLUSIONS: The present study supported the response-conflict view of Ne/ERN. Furthermore, the observed relationship between impulsivity and Ne/ERN amplitude suggested that individuals with low behavioral control were characterized by lower activity in anterior cingulate cortex, the neural generator of Ne/ERN, in situations of strong response conflict. SIGNIFICANCE: The present study, for the first time, employed a stop-signal paradigm to verify predictions regarding the temporal dynamics of response-conflict processing as derived from response-conflict theory of ERN.

Adult↗

PubMed2006

ERP predictors of individual performance on a prospective temporal reproduction task.

The present study aimed at investigating whether different aspects of performance on a prospective reproduction task with a standard duration of 2 s had different antecedents in the event-related potentials (ERPs) accompanying standard presentations and reproduced intervals. On each trial, first the standard duration was presented as an empty auditory interval. After a short delay, participants reproduced this interval by means of two button presses defining onset and offset of the reproduced interval. About 25 participants were divided into groups of poor and good time estimators, once based on the coefficient of variation of their reproduced durations, and once based on the absolute error score. Interestingly, for both performance measures differences between participants were accompanied by ERP differences during standard presentations rather than reproduction itself. While larger P300 amplitudes evoked by standard interval offset predicted good reproduction performance in terms of a small coefficient of variation, small absolute error scores were accompanied by larger fronto-central negative slow wave during standard presentations. The results suggest an important role of attention to both the critical events that delimit the to-be-estimated temporal intervals, and to the passing of time between these events.

Adolescent↗

PubMed2006

Response-time corrected averaging of event-related potentials.

OBJECTIVE: The present study presents a novel approach to averaging of event-related potentials (ERPs). Acknowledging latency variability of late ERP components as related to performance fluctuations across trials should improve the assessment of late portions of the ERP. METHODS: Prior to the averaging procedure stimulus-to-response epochs in the electroencephalogram (EEG) were expanded/compressed in time to match mean RT in a certain condition and participant. By means of several mathematical functions RT variability was differentially distributed over late vs. early portions of the ERP. Data from 20 participants from two conditions of an identity-based priming task were analyzed using traditional stimulus- and response-locked averaging, as well as four different RT-corrected averaging procedures. RESULTS: Area under the curve as an index of precision of LPC assessment was reliably enhanced for certain RT-corrected procedures relative to traditional ERP averaging. Moreover, a priming effect on amplitude of a distinct LPC subcomponent which could not be confirmed with traditional stimulus-locked averaging was reliably born out using a cubic RT-correction procedure. CONCLUSIONS: RT-corrected ERP averaging can outperform traditional ERP averaging in the assessment of late portions of the ERP, and experimental effects upon. SIGNIFICANCE: Cognitive ERP researchers may take advantage of the improved capability of RT-corrected averaging to establish experimental effects on amplitudes in the late ERP range.

Adult↗

PubMed2006

Sensorimotor effects of pergolide, a dopamine agonist, in healthy subjects: a lateralized readiness potential study.

OBJECTIVE: The major purpose of the present study was to further elucidate dopaminergic modulation of sensorimotor processing in healthy human subjects. MATERIALS AND METHODS: To more specifically analyze dopaminergic effects on premotor and motor stages of sensorimotor processing, lateralized readiness potentials (LRPs) were obtained. In a randomized double-blind crossover design, either 0.075 mg of the D1/D2 dopamine (DA) agonist pergolide or placebo were administered to 12 healthy male volunteers ranging from 19 to 25 years in age. The subjects performed a two-choice visual reaction time task. In addition to behavioral measures, such as response speed and error rate, stimulus-locked LRP (S-LRP) and response-locked LRP (LRP-R) latencies were determined. To better dissociate potential central and peripheral motor effects, measures of response dynamics and response-locked electromyogram (EMG-R) recordings were also obtained. OBSERVATIONS: Pergolide reliably enhanced speed of stimulus-related information processing as indicated by shorter S-LRP latencies while LRP-R latencies, reaction time, and indicators of response dynamics were not influenced by DA agonistic treatment. Furthermore, lower EMG-R amplitudes and an increased number of wrong-hand responses were observed under pergolide compared to placebo. CONCLUSION: The results indicate that dopaminergic neurotransmission effectively modulates early perceptual and cognitive stages of information processing as suggested by neural network models of the functional role of prefrontal DA. The lack of an effect on aspects of motor processing may be due to a higher capacity of the nigrostriatal compared to the mesocortical DA system to compensate pharmacologically induced changes in dopaminergic activity.

Adult↗

PubMed2006

Multiple sources of positive- and negative-priming effects: an event-related potential study.

Event-related potential correlates of positive priming (PP) and negative priming (NP) were investigated in order to further elucidate the cognitive mechanisms involved. Thirty-six participants performed both an identity- and a location-based priming task. Repeating the target stimulus/location from the immediately preceding display produced behavioral PP. With localization, but not with identification, behavioral NP was observed when the target stimulus/location matched the preceding distractor stimulus/location. Smaller P300 amplitude accompanied identity-based PP, suggesting persisting target-specific activation. The lateralized readiness potential, an index of correct/incorrect response activation, indicated persisting central motor activation as another source of PP. Both location-based PP and NP were accompanied by reduced P1/N1 and P300 amplitudes, pointing to the involvement of inhibition of return in location-based priming. The results support the view that multiple brain processes underlie behavioral priming.

Adult↗

PubMed2005

Accessory stimulation in the time course of visuomotor information processing: stimulus intensity effects on reaction time and response force.

A series of three visual choice-reaction time experiments were performed to systematically investigate the effects of accessory auditory stimulation on response time (RT) and response force (RF). In Experiment 1, the effect of accessory auditory stimulation on early visual information processing was investigated. Experiments 2 and 3 were designed to examine the effects of accessory intensity on RT and RF across the entire time course of sensorimotor processing. Accessory stimulation accelerated response speed only when presented within 100 ms after onset of the visual response signal. An enhancing effect of accessory stimulation on RF, however, was found as late as 220 ms after onset of the response signal. These findings support the notion that response speed and response dynamics represent functionally independent sensorimotor phenomena.

Female↗

PubMed2004

Differences in the transmission of sensory input into motor output between introverts and extraverts: Behavioral and psychophysiological analyses.

The present study was designed to investigate extraversion-related individual differences in the speed of transmission of sensory input into motor output. In a sample of 16 introverted and 16 extraverted female volunteers, event-related potentials, lateralized readiness potentials (LRPs), and electromyogram (EMG) were recorded as participants performed a visual choice reaction time task. As additional behavioral indicators of performance, measures of reaction time (RT) and response dynamics were obtained. Although extraversion-related differences were found neither for behavioral measures nor for the N1 and P3 components of the evoked potential, introverts showed a reliably shorter latency in stimulus-locked LRP than extraverts. This latter finding supports the notion of faster stimulus analysis in introverts compared to extraverts. Furthermore, there was no indication of extraversion-related individual differences in speed of response organization and response execution as indicated by response-locked LRP and EMG latencies, respectively. However, a significantly higher EMG amplitude observed with introverts pointed to a less accurately adjusted motor output system of introverts compared to extraverts.

Adult↗

PubMed2004

Extraversion-related differences in response organization: evidence from lateralized readiness potentials.

Research utilizing a mental-chronometry approach to examine individual differences in extraversion suggests that extraversion-related individual differences may involve stimulus analysis, response organization, and peripheral motor processes. In a sample of 14 introverted and 14 extraverted female volunteers event-related potentials (ERP) and lateralized readiness potentials (LRPs) were recorded concurrently with reaction time (RT) measures as participants performed a two-choice go/no-go task. Although there were no extraversion-related differences in mean reaction time, introverts showed higher N1 amplitudes and shorter P3 latencies compared to extraverts. Furthermore, response-locked LRP latencies were reliably shorter for extraverts than for introverts. The latter finding provides first direct evidence for the contribution of central processes related to motor activation to account for extraversion-related individual differences.

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↗