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Correct Trials (correct + trials)

Distribution by Scientific Domains

Psychology	50%

Selected Abstracts

An electromyographic investigation of the effect of stimulus,response mapping on choice reaction time

PSYCHOPHYSIOLOGY, Issue 1 2001
Thierry Hasbroucq
The activity of the agonist muscles was recorded during the performance of a two-choice visual reaction time (RT) task in which the compatibility of the stimulus,response mapping was manipulated. Correct trials were distinguished according to whether or not the activation of the agonist of the required response was preceded by an activation of the agonist of the nonrequired response. Double activation trials were more numerous for the incompatible than for the compatible mapping. Furthermore, these trials yielded longer RTs than the single muscular activation trials. These results suggest that initial activations of nonrequired responses are more frequently aborted and corrected when the mapping is incompatible than when it is compatible. This finding supports the dimensional overlap model of stimulus,response compatibility (S. Kornblum, T. Hasbroucq, & A. Osman, 1990). [source]

Visuospatial encoding deficits and compensatory strategies in schizophrenia revealed by eye movement analysis during a working memory task

ACTA NEUROPSYCHIATRICA, Issue 2 2009
Luca Cocchi
Objective: To investigate scanpath abnormalities during the encoding of static stimuli in schizophrenia and their interaction with visuospatial working memory (VSWM) dysfunction. Methods: Outpatients with schizophrenia and control subjects were asked to encode a static pattern for subsequent recognition after a short delay. We measured the number of correct and incorrect choices. We also assessed the number and the distribution of fixations, the scanning time in specific regions of interest (ROIs) and the head movements during the encoding of the stimuli. The distributions of fixations and scanning time in definite ROIs during the discrimination of the correct pattern from the foils were also measured. Results: Patients recognised fewer correct patterns than controls. Correct trials in patients were characterised by a specific exploration of the central part of the stimulus during its presentation, whereas this feature was absent in incorrect trials. However, the scanning time and the numbers of fixations and head movements during encoding were similar in both groups and unrelated to recognition accuracy. In both groups, correct trials were associated with a selective exploration of the correct pattern amongst the six possibilities during recognition. Furthermore, patients gave more attention to incorrect patterns with a leftmost element identical to that of the correct response and also those approximating its global structure. Conclusion: Patients showed a VSWM deficit independent of oculomotor dysfunctions and head movements during encoding. Patients' correct trials were related to specific scanning during encoding and discrimination phases. Analysis of these patterns suggests that patients try to compensate for reduced VSWM ability by using specific encoding strategies. [source]

Independent component analysis of erroneous and correct responses suggests online response control

HUMAN BRAIN MAPPING, Issue 9 2010
Sven Hoffmann
Abstract After errors in reaction tasks, a sharp negative wave emerges in the event-related potential (ERP), the error (related) negativity (Ne or ERN). However, also after correct trials, an Ne-like wave is seen, called CRN or Nc, which is much smaller than the Ne. This study tested the hypothesis whether Ne and Nc reflect the same functional process, and whether this process is linked to online response control. For this purpose, independent component analysis (ICA) was utilized with the EEG data of two types of reaction tasks: a flanker task and a mental rotation task. To control for speed-accuracy effects, speed and accuracy instructions were balanced in a between subjects design. For both tasks ICA and dipole analysis revealed one component (Ne-IC) explaining most of the variance for the difference between correct and erroneous trials. The Ne-IC showed virtually the same features as the raw postresponse ERP, being larger for erroneous compared to correct trials and for the flanker than for the rotation task. In addition, it peaked earlier for corrected than for uncorrected errors. The results favor the hypothesis that Ne and Nc reflect the same process, which is modulated by response correctness and type of task. On the basis of the literature and the present results, we assume that this process induces online response control, which is much stronger in error than correct trials and with direct rather than indirect stimulus response mapping. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc. [source]

Transposition of line-length discrimination in African penguins (Spheniscus demersus),

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 3 2009
KAZUCHIKA MANABE
Abstract Four penguins (Spheniscus demersus) were trained to discriminate line length in a simultaneous discrimination task. After the birds' performances reached a discrimination criterion, the reinforcement ratio was decreased to .33. After the ratio of correct trials reached .90 in three successive sessions with a partial reinforcement procedure, probe-test sessions were introduced. In the probe-test trials, untrained lines were presented paired with the trained lines. The four probe-test trials were mixed into 45 discrimination trials. In the probe-test trials, the penguins that had been trained to peck shorter lines pecked the untrained shorter line rather than the longer line that was reinforced in the discrimination trials. In contrast, those birds that had been trained to peck the longer line pecked the untrained longer line, rather than the shorter line which was reinforced in the discrimination trials. All four birds demonstrated transposition in the line-length discrimination task. [source]

Alpha power is influenced by performance errors

PSYCHOPHYSIOLOGY, Issue 2 2009
Joshua Carp
Abstract Error commission evokes changes in event-related potentials, autonomic nervous system activity, and behavior, presumably reflecting the operation of a cognitive control network. Here we test the hypothesis that errors lead to increased cortical arousal, measurable as changes in electroencephalogram (EEG) alpha band power. Participants performed a Stroop task while EEG was recorded. Following correct responses, alpha power increased and then decreased in a quadratic pattern, implying transient mental disengagement during the intertrial interval. This trend was absent following errors, which elicited significantly less alpha power than correct trials. Moreover, post-error alpha power was a better predictor of individual differences in post-error slowing than the error-related negativity (ERN), whereas the ERN was a better predictor of post-error accuracy than alpha power. These findings imply that changes in cortical arousal play a unique role in modulating post-error behavior. [source]

The feedback correct-related positivity: Sensitivity of the event-related brain potential to unexpected positive feedback

PSYCHOPHYSIOLOGY, Issue 5 2008
Clay B. Holroyd
Abstract The N200 and the feedback error-related negativity (fERN) are two components of the event-related brain potential (ERP) that share similar scalp distributions, time courses, morphologies, and functional dependencies, which raises the question as to whether they are actually the same phenomenon. To investigate this issue, we recorded the ERP from participants engaged in two tasks that independently elicited the N200 and fERN. Our results indicate that they are, in fact, the same ERP component and further suggest that positive feedback elicits a positive-going deflection in the time range of the fERN. Taken together, these results indicate that negative feedback elicits a common N200 and that modulation of fERN amplitude results from the superposition on correct trials of a positive-going deflection that we term the feedback correct-related positivity. [source]