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M Falkenstein

Publications and source records attributed to M Falkenstein.

At least 19 recordsLinked to original sources
PubMed2001

Action monitoring, error detection, and the basal ganglia: an ERP study.

The error negativity (Ne or ERN) is an event-related brain potential component, which is assumed to reflect error detection. Recently it has been hypothesized that the basal ganglia are assumed to play a crucial role in error detection. In the present study we ask whether the Ne is altered in patients with Parkinson's disease (PD), who have an impaired function of the basal ganglia. We recorded the Ne in patients and in matched controls, while they performed different tasks that require a relatively high cognitive control, which is supposed to pose particular problems on PD. The Ne was in fact smaller in the patients than in the controls in all tasks. Our results suggest an impairment of error detection in PD for different types of demanding tasks. This supports the hypothesis that the basal ganglia do play an important role for error detection in action monitoring.

Aged↗
PubMed2000

ERP components on reaction errors and their functional significance: a tutorial.

Some years ago we described a negative (Ne) and a later positive (Pe) deflection in the event-related brain potentials (ERPs) of incorrect choice reactions [Falkenstein, M., Hohnsbein, J., Hoormann, J., Blanke, L., 1990. In: Brunia, C.H.M., Gaillard, A.W.K., Kok, A. (Eds.), Psychophysiological Brain Research. Tilburg Univesity Press, Tilburg, pp. 192-195. Falkenstein, M., Hohnsbein, J., Hoormann, J., 1991. Electroencephalography and Clinical Neurophysiology, 78, 447-455]. Originally we assumed the Ne to represent a correlate of error detection in the sense of a mismatch signal when representations of the actual response and the required response are compared. This hypothesis was supported by the results of a variety of experiments from our own laboratory and that of Coles [Gehring, W. J., Goss, B., Coles, M.G.H., Meyer, D.E., Donchin, E., 1993. Psychological Science 4, 385-390. Bernstein, P.S., Scheffers, M.K., Coles, M.G.H., 1995. Journal of Experimental Psychology: Human Perception and Performance 21, 1312-1322. Scheffers, M.K., Coles, M. G.H., Bernstein, P., Gehring, W.J., Donchin, E., 1996. Psychophysiology 33, 42-54]. However, new data from our laboratory and that of Vidal et al. [Vidal, F., Hasbroucq, T., Bonnet, M., 1999. Biological Psychology, 2000] revealed a small negativity similar to the Ne also after correct responses. Since the above mentioned comparison process is also required after correct responses it is conceivable that the Ne reflects this comparison process itself rather than its outcome. As to the Pe, our results suggest that this is a further error-specific component, which is independent of the Ne, and hence associated with a later aspect of error processing or post-error processing. Our new results with different age groups argue against the hypotheses that the Pe reflects conscious error processing or the post-error adjustment of response strategies. Further research is necessary to specify the functional significance of the Pe.

Adult↗
PubMed2000

Different error types and error processing in spatial stimulus-response-compatibility tasks: behavioural and electrophysiological data.

We tested the hypothesis that in spatial stimulus-response-compatibility (SRC) tasks two different error types occur: A noise-induced 'general error' independent of SRC and reaction time and a 'position driven error' in incompatible trials with short RT being driven by the irrelevant stimulus position. A second issue was whether error detection is different for these two types of errors, which should be reflected by differences in the error negativity (Ne), since the Ne is seen as a neural correlate of error detection. To study these issues, we used a Simon- and a spatial Stroop-task. In incompatible (vs. compatible) trials we found more errors and a below chance accuracy in fast responses. Neither the amplitude nor the latency of the Ne were significantly affected by the experimental factors. This pattern of behavioural results supports the above hypothesis of two error types in such tasks. The Ne results indicate that error detection is similar for both types of errors.

Adult↗
PubMed2000

To err is human.

Explore the source record for details and available documents.

Brain↗
PubMed2000

Early attention effects in human auditory-evoked potentials.

A fundamental question in attention theory concerns the earliest processing stages that can be modulated by selective attention. A series of experiments is reported in which very early attention effects are found under specific conditions in the frequency-following potential (FFP), a brain stem response to low-frequency tone stimuli. In two experiments, stimuli of two different modalities were applied, and attention directed to one of the modalities. In two further experiments, only auditory stimuli were presented. In the first of these last two experiments, a dichotic paradigm with sustained attention to one ear was used, in the second a monotic paired-stimuli paradigm was used, in which the first stimulus served as reference for the second one. Only in the last experiment significant attention effects were found in the latency, but not in the amplitude of the FFP. The results show that a very early attention effect on the latency of the FFP can be demonstrated, but only under highly specific conditions. The size and preconditions of the attention effect suggest that it reflects subtle intramodal tuning mechanisms in the cochlea or in the lower brain stem.

Acoustic Stimulation↗
PubMed1999

ERP components in Go/Nogo tasks and their relation to inhibition.

In visual Go/Nogo tasks the ERP usually shows a frontal negativity after Nogo stimuli ("Nogo-N2"), which possibly reflects an inhibition process. However, the Nogo-N2 appears to be very small after auditory stimuli, which is evidence against the inhibition hypothesis. In the present study we tested this hypothesis by evaluating performance differences between subjects. Assuming that for Ss with a high false alarm rate the inhibition process is weakened and/or delayed, they should reveal a smaller and/or later Nogo-N2 than Ss with a low false alarm rate. This prediction was confirmed, which supports the inhibition hypothesis. However, the Nogo-N2 was again much smaller and had a different topography after auditory than after visual stimuli despite similar performance in both modalities. This modality asymmetry was explained by assuming that the inhibitory mechanism reflected in the Nogo-N2 is located at a pre-motor rather than at the motor level. In the second part of the study we compared the Nogo-N2 with a similar phenomenon, the error negativity (Ne), which occurs in trials with commission errors (false alarms). Earlier work suggests that the Ne is a correlate of error detection or inhibition. This raises the possibility that the Ne is a delayed Nogo-N2, i.e., the Ne may reflect a late and hence unsuccessful attempt to inhibit the response after a nontarget. However, the Ne amplitude showed no difference between performance groups and stimulus modalities, as found for the Nogo-N2. Moreover, Ne and Nogo-N2 had different scalp topographies. This suggests that different mechanisms and generators underlie the Ne and the Nogo-N2.

Adolescent↗
PubMed1998

Performance differences in reaction tasks are reflected in event-related brain potentials (ERPs).

Event-related potentials (ERPs), which can be extracted from the electroencephalogram (EEG), are assumed to reflect distinct cognitive processes in real time. Hence ERP analysis could be used in cognitive ergonomics as a tool to specify, for example, bottlenecks or sources of individual performance differences. Such specific results may be helpful to change the tasks or train the subjects specifically. In the present exploratory study, the authors investigated whether subjects with large spontaneous differences in performance accuracy, as defined by their error rates in a speeded binary choice reaction task, also differ in the structure of their ERPs. The ten subjects were divided post hoc into two groups with relatively low (about 6%) and high (about 20%) error rates. While the reaction times were not significantly different for both groups, the ERPs revealed clear group differences. First, large differences were seen in the late part of the contingent negative variation (late CNV), which is assumed to reflect preparatory processes. Subjects with few errors ('GOOD') had a large late CNV, while subjects with many errors ('POOR') showed virtually no late CNV. Second, the late P300-subcomponent (which is related to response identification) was smaller and delayed for POOR compared to GOOD subjects. Finally, the ERP shows signs of poor movement control in POOR subjects. The high error rate of POOR subjects can hence be explained by: (1) their insufficient preparation for the next trial (small late CNV), which impaired response identification (small and delayed late P300 subcomponent); and (2) their poor movement control. These interpretations have to be regarded as preliminary and should be validated with larger groups of subjects. In conclusion, the main reasons for the profound performance differences between the groups, namely differential preparation and movement control, could be elucidated by ERP analysis. A potential ergonomics application of these results is that they suggest specific strategies (for example, a preparation and motor control training) to improve the performance of POOR subjects in comparable work conditions.

Adult↗
PubMed1997

A method to improve the latency estimation of the frequency-following potential (FFP).

If the latency of a noisy frequency-following potential (FFP) is estimated by determining the shift of the (periodical) cross-correlation function (CCF) between the stimulus and the FFP, the result may be unambiguous only within +/-1 or +/-2 periods of the CCF, because the absolute maximum and adjacent local maxima may not be significantly different. Here we present a method to amplify this difference by applying amplitude modulated stimuli. Using this method we first illustrate the effect of the method by a simulation and then demonstrate its usefulness by measuring real FFPs and estimating their latencies.

Artifacts↗
PubMed1997

[Event-related potential components related to errors].

Event-related potentials (ERPs) of error trials in choice tasks and Go/Nogo tasks are found to be considerably different from the ERPs of the correct trials: In error trial ERPs there is an additional negative (Ne) and an additional positive component (Pe) compared to correct trials. Amplitude and latency variation of both components in different experiments supports the hypothesis that these components reflect different aspects of error processing. The Ne is interpreted as a real-time correlate of error detection, as defined by a mismatch between cognitive representations of the erroneous response and the correct response. The variation of Pe with experimental variables is different from that of the Ne and it also from that of positive components in correct trials, and may therefore reflect an additional aspect of error processing, such as change of response strategies.

Adult↗
PubMed1995

Late ERP components in visual and auditory Go/Nogo tasks.

In an audio-visual Go/Nogo paradigm we studied whether the Go/Nogo difference, usually found in the time range of the visual N2, is also present after auditory stimuli, which bears on the common response inhibition hypothesis of this N2 effect. Moreover the possible presence and variation of P300 subcomponents were studied with the goal of clarifying the reasons for the commonly observed P300 topography changes between Go and Nogo trials. To disentangle possible P300 subcomponents we applied a crossmodal divided attention (DA) condition, in which the subcomponents are known to be separated after auditory stimuli in choice tasks. An N2 effect was found after visual but not after auditory stimuli, which is evidence against the response-inhibition hypothesis. After visual stimuli a positive complex (P400) was seen, whereas after auditory stimuli two dissociated components (P400 and P507) were found instead. The P507 had a parietal maximum for both Go and Nogo trials. It was larger and it peaked later in Go than in Nogo trials. The P400 showed topographic differences between Go and Nogo trials, which could be explained by the overlap of the two subcomponents. We assume that (i) both subcomponents have a stable topography across response type, and (ii) the first subcomponent is invariant with response type, whereas the second (which overlaps the first one) is larger and peaks later on Go than on Nogo trials.

Acoustic Stimulation↗
PubMed1995

Effects of attention and time-pressure on P300 subcomponents and implications for mental workload research.

Our approach to objective measures of mental workload is establishing relationships between components of the event-related brain potential (ERP) and information processing stages. These relationships can be used to infer the influence of specific workload conditions on specific processing stages. We recently showed that the ERP component P300 in choice tasks is composed of two subcomponents, P-SR and P-CR, which are time-related to stimulus-evaluation and response-selection. With these relations we could specify which processing stages were affected when certain workload conditions are varied. When attention was divided between the visual and auditory modalities compared to (unimodal) focused attention, the choice reaction time (RT) was prolonged, primarily in the auditory modality. This delay was mainly reflected in the P-CR latency, which shows that the division of attention mainly impairs the response-selection process in the auditory modality due to a bias of attention towards the visual modality. When the time-pressure was increased, the latency of the P-CR (and not of the P-SR) was shortened, but less than the choice RT. This suggests a (limited) acceleration of response-selection but not of stimulus evaluation. Since the response-selection process was accelerated less than the overt choice RT, an increase of the error rate was consequently observed. In summary we showed that increases of mental workload can induce accelerations or decelerations of specific processing stages which can be monitored by observing latency changes of the affiliated ERP components.

Adult↗
PubMed1994

Effect of selective attention on the latency of human frequency-following potentials.

While effects of attention on late and middle latency components of the evoked potential have been demonstrated, similar effects on brain stem evoked potentials--in particular on the human frequency-following potential (FFP)--are controversial. The FFP is a response to tone bursts in the frequency range of human language (optimum approximately 350 Hz). It has a latency of approximately 6.3 ms and is probably generated at a site peripheral to the inferior colliculus. We present data showing that the latency of the FFP can be shortened significantly (45 microseconds) if the subject is required to attend to the evoking auditory tone burst, while the amplitude of the FFP remains unaffected. This indicates an attention-controlled influence on signal processing in the earliest parts of the auditory pathway.

Acoustic Stimulation↗
PubMed1994

Effects of choice complexity on different subcomponents of the late positive complex of the event-related potential.

The effects of choice complexity on different subcomponents of the late positive complex were investigated. In a previous choice reaction study, two subcomponents of this complex were identified, called P-SR and P-CR, which seem to be related to stimulus evaluation and response selection, respectively. The present study attempts to show the dependence of the P-CR (and the independence of the P-SR) on response selection by manipulating response selection complexity. This was done by having the subjects perform either 2-way or 4-way choice reactions to single letter stimuli. To enhance the discriminability of P-SR and P-CR, visual and auditory stimuli were used, since the P-SR is modality-dependent. Moreover, the stimulus modalities were mixed ("divided attention paradigm"), which was expected to lead to a dissociation of P-SR and P-CR, especially after auditory stimuli. The choice reaction times were about 100 msec longer for difficult than for easy choices. The main ERP result was a 65 msec increase of the P-CR latency for the difficult as compared to the easy choice, while the P-SR latency remained constant. The P-CR latency difference precisely matched the onset difference of the lateralized readiness potential. The P-SR showed a modality-dependent latency and topography, while the P-CR did not. The present data confirm the close relation of one subcomponent of the late positive complex, the P-CR, to the cognitive response-selection process.

Acoustic Stimulation↗
PubMed1993

Late visual and auditory ERP components and choice reaction time.

Some relations between different late positive ERP components and choice reaction time (RT) were studied. In order to identify the different components we used visual and auditory stimuli, as well as simple and choice reaction tasks, since one of the components is thought to be modality dependent and the other one task dependent. In the paradigm the stimulus modalities were mixed, which was expected to lead to a maximum dissociation of the components after auditory stimuli (Hohnsbein et al. (1991). Electroencephalography and Clinical Neurophysiology, 78, 438-446). The results demonstrated the overlap of two positive waves in choice reaction tasks: a central one (P-SR), and a parietal one (P-CR). The latency of the P-SR varied greatly across modalities, but did not vary with RT, whereas the latency of the P-CR varied strongly with RT. The different overlap of these components on fast and slow trials caused amplitude and latency variations of the "P300" and the positive slow wave. Our results suggest a relation of the P-SR with stimulus evaluation (identification), and of the P-CR with response selection (stimulus-response mapping).

Adolescent↗
PubMed1992

The human frequency-following response (FFR): normal variability and relation to the click-evoked brainstem response.

The frequency-following response (FFR) was recorded from twenty human subjects (11 female and 9 male) over a frequency range of 128-832 Hz in order to study the normal variability of this evoked potential and its dependence on age and sex. Moreover the relation of the FFR to the click-evoked brain stem response (BER) was analyzed in order to contribute to the FFR source discussion. The FFR had a maximum amplitude of about 400 nV and a latency of about 6.4 ms for stimulus frequencies around 350 Hz; the inter-individual variance of the best frequency and of the shape of the frequency function was considerable. Large second harmonics were seen in the FFR to stimuli below about 200 Hz. The FFR amplitude tended to be larger in younger subjects, whereas no such effect was found for the BER. No significant sex effect was found for the FFR amplitude, whereas the BER waves IV and VI were larger for females than for males. There were no correlations between FFR and BER latencies. Significant correlations were found between the amplitudes of the FFR and BER components II, III and IV, but not of waves V and VI. The results support the notion that the FFR and the BER reflect different mechanisms. Moreover the results do not favor the common hypothesis that the inferior colliculus is the major source of the scalp-recorded human FFR, but rather point to lower brainstem levels.

Acoustic Stimulation↗