Biomedical subjects

K R Ridderinkhof

Publications and source records attributed to K R Ridderinkhof.

11 recordsLinked to original sources

PubMed2006

Inefficient response inhibition in individuals with mild cognitive impairment.

Individuals diagnosed with mild cognitive impairment (MCI) show primary deficits in memory and are at increased risk for developing Alzheimer's disease (AD). In light of recent evidence that executive cognitive deficits are common in AD and may be detectable in individuals diagnosed with MCI, we extend these findings to the investigation of response inhibition, an essential aspect of executive cognitive control. Twenty MCI patients and 20 healthy controls (HC) completed an arrow version of the flanker task [Eriksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters upon the identification of target letters in a non-search task. Perception & Psychophysics, 16, 143-149] in which participants responded to a target arrow surrounded by distractors (i.e., flankers) that signaled a same (congruent) or a conflicting (incongruent) response. Reaction time (RT) increased in both groups when flankers signaled an incongruent response, but more so among MCI patients. MCI patients taking a cholinesterase inhibitor showed smaller flanker interference effects than those not taking this medication. Analysis of the flanker effect as a function of the entire RT distribution indicated that MCI patients show increasing interference at the slowest segments of the distribution, a finding that implicates deficient inhibition of the incongruent response [Ridderinkhof, K. R. (2002). Activation and suppression in conflict tasks: Empirical clarification through distributional analyses. In W. Prinz & B. Hommel (Eds.), Common mechanisms in perception and action. Attention & performance, Vol. XIX (pp. 494-519). Oxford: Oxford University Press]. These results suggest that deficits in response inhibition are detectable in MCI patients and merit further investigation as to whether these changes aid prediction of which MCI patients convert to AD.

Aged↗

PubMed2005

Effects of stop-signal modality on the N2/P3 complex elicited in the stop-signal paradigm.

The principal aim of the present study was to clarify how stop-signal modality affected the speed and efficacy of stopping, using ERP components as converging measures of stop processes. Both performance and ERP latency findings suggested faster processing of stop signals in the auditory than visual version of the stop task. The effects of successful versus unsuccessful stopping on the amplitude and topography of N2/P3 components elicited by the stop signals appeared to be largely independent of the modality of the stop signals. Stop signals elicited a fronto-central N2 that was much larger on unsuccessful than successful stop trials in stimulus-locked waveforms. N2 was followed by a P3 component that showed a fronto-central distribution on successful stop trials. P3 elicited on unsuccessful stop trials showed a posterior-parietal focus, but this topography was manifested more clearly in response-locked than stimulus-locked waveforms. A dipole source analyses confirmed these topographical differences of P3, and further showed that the location of the corresponding dipoles remained largely identical across the visual and auditory versions of the stop-signal task. Taken together, the present findings support the suggestion that ERP components in the stop task reflect endogenous aspects of stop-signal processing, such as effective inhibition of responses on successful stop trials and detection of errors on failed inhibition trials.

Adult↗

PubMed2004

Effects of stop-signal probability in the stop-signal paradigm: the N2/P3 complex further validated.

The aim of this study was to examine the effects of frequency of occurrence of stop signals in the stop-signal paradigm. Presenting stop signals less frequently resulted in faster reaction times to the go stimulus and a lower probability of inhibition. Also, go stimuli elicited larger and somewhat earlier P3 responses when stop signals occurred less frequently. Since the amplitude effect was more pronounced on trials when go signals were followed by fast than slow reactions, it probably reflected a stronger set to produce fast responses. N2 and P3 components to stop signals were observed to be larger and of longer latency when stop signals occurred less frequently. The amplitude enhancement of these N2 and P3 components were more pronounced for unsuccessful than for successful stop-signal trials. Moreover, the successfully inhibited stop trials elicited a frontocentral P3 whereas unsuccessfully inhibited stop trials elicited a more posterior P3 that resembled the classical P3b. P3 amplitude in the unsuccessfully inhibited condition also differed between waveforms synchronized with the stop signal and waveforms synchronized with response onset whereas N2 amplitude did not. Taken together these findings suggest that N2 reflected a greater significance of failed inhibitions after low probability stop signals while P3 reflected continued processing of the erroneous response after response execution.

Adolescent↗

PubMed2001

Error-related brain potentials are differentially related to awareness of response errors: evidence from an antisaccade task.

The error negativity (Ne/ERN) and error positivity (Pe) are two components of the event-related brain potential (ERP) that are associated with action monitoring and error detection. To investigate the relation between error processing and conscious self-monitoring of behavior, the present experiment examined whether an Ne and Pe are observed after response errors of which participants are unaware. Ne and Pe measures, behavioral accuracy, and trial-to-trial subjective accuracy judgments were obtained from participants performing an antisaccade task, which elicits many unperceived, incorrect reflex-like saccades. Consistent with previous research, subjectively unperceived saccade errors were almost always immediately corrected, and were associated with faster correction times and smaller saccade sizes than perceived errors. Importantly, irrespective of whether the participant was aware of the error or not, erroneous saccades were followed by a sizable Ne. In contrast, the Pe was much more pronounced for perceived than for unperceived errors. Unperceived errors were characterized by the absence of posterror slowing. These and other results are consistent with the view that the Ne and Pe reflect the activity of two separate error monitoring processes, of which only the later process, reflected by the Pe, is associated with conscious error recognition and remedial action.

Adolescent↗

PubMed2000

Attention and selection in the growing child: views derived from developmental psychophysiology.

Our understanding of developmental changes in attentional selection in the growing child has been advanced substantially by the results of (a relatively small number of) studies undertaken from a psychophysiological perspective. The basic outcome of these studies is that, in attentional filtering as well as selective set (the two basic paradigms in attention research), the processes necessary for attentional selection are in essence available even to the young child; however, the speed and efficiency of these processes tends to increase as the child grows into an adolescent. Under optimal conditions, filtering is performed at early stages of information processing, but less optimal stimulus characteristics and task requirements may induce a shift in the locus of selection to later processing stages for young children whereas older individuals are better able to preserve their early locus of selection. When early selection is constrained, young children are substantially more sensitive to the adverse effects of response competition. In selective set, sub-optimal conditions lead not so much to a shift in locus of selection processes, but to a shift in the age at which asymptote efficiency is attained. We have proposed hierarchical regression analysis as a useful technique to examine whether age-related differences in attention effects, as observed in specific ERP components and in RT, are reflections of an age effect on a single source of attentional selection or of separate sources that each contribute uniquely to the developmental trends seen in (attention effects on) RT. Re-analyses of existing data demonstrated that (again depending on task specifics) many but not all of the different component processes involved in attentional selection contributed unique variance to the age-related changes in attention effects.

Adolescent↗

PubMed2000

Inhibitory inefficiency and failures of intention activation: age-related decline in the control of saccadic eye movements.

Young and older adults' control of saccadic eye movements was compared using an antisaccade task, which requires the inhibition of a reflexive saccade toward a peripheral onset cue followed by an intentional saccade in the opposite direction. In 2 experiments, an age-related decline was found in the suppression of reflexive eye movements, as indicated by an increased proportion of saccades toward the cue, and a longer time needed to initiate correct antisaccades. The results from Experiment 2 suggested that older adults' slower antisaccades may be explained partly in terms of increased failures to maintain the cue-action representation at a sufficient activation level. The results suggest that the notion of selective preservation with age of the ability to inhibit spatial responses does not apply to the active inhibition of prepotent spatial responses.

Adolescent↗

PubMed1997

Mental resources, processing speed, and inhibitory control: a developmental perspective.

The present article addresses the claim that the speed of information processing qualifies as a processing resource. This claim contends that age-related changes in processing speed pertain to all cognitive processes to the same proportional degree. That is, processing speed is compared to the clock speed of a microcomputer: as young children's clock speed increases, the speed of processing in all cognitive processes increases until the adult level is reached. Re-analyses of recent behavioral and psychophysiological data provide evidence against the notion that development is characterized by an increase in children's global clock speed, and refute the claim that processing speed operates as a mental resource on which all cognitive processes depend to the same extent. Rather, the results emphasize the role of inhibitory control in cognitive development, and we consider the relevance of inhibitory development to the issue of age-related changes in processing capacity.

Evoked Potentials↗

PubMed1997

Is the age-complexity effect mediated by reductions in a general processing resource?

The rate of information processing, as revealed in measures of reaction time, slows with advancing age and this slowing is most evident as processing complexity increases. This phenomenon, known as the Age-Complexity effect, has been attributed to general changes in the speed of processing that affect all components of processing indiscriminantly, both within and across tasks in a particular processing domain. That the slowing is thought to be task- and process-independent has led to the additional inference that it reflects reductions in a general processing resource. On the basis of converging evidence identified in a review of both behavioral and chronopsychophysiological studies, we argue that the slowing induced by older age is not generalized, but rather is both task-dependent and process-specific and, as such, cannot be explained in terms of a diminished general processing resource. We close by speculating that elements of the age-induced slowing can be interpreted within the context of the cognitive-energetical model.

Age Factors↗

PubMed1997

Sources of interference from irrelevant information: a developmental study.

The present study investigated the mechanisms underlying reductions in the susceptibility to interference from irrelevant information that are evident in the developing child. In the first experiment, where the task was to focus on one stimulus dimension and to ignore a second dimension, variations in the degree of spatial integration in multidimensional stimulus configurations did not influence interference effects. Developmental trends in selective attention could not be attributed to age changes in the accessibility of dimensional structure. The second experiment, where the task was to focus on a central arrow stimulus and to ignore flanking arrows, allowed further examination of the mechanisms involved in developmental changes in interference effects. The primary source of the developmental decrease in interference from irrelevant information was found to be in the rate at which the output of perceptual analysis is coupled to the preparation and execution of a motor response, rather than in perceptual filtering or in response preparation. The combined results suggest that age changes in selective attention are mediated to an important extent by changes in the speed and efficiency of stimulus-response translation processes. These findings are discussed in terms of developmental theories of interference control.

Attention↗

PubMed1995

When global information and local information collide: a brain potential analysis of the locus of interference effects.

The objective of the current experiment was to perform a psychophysiological investigation of the interference effects of global information on the analysis of local information, and vice versa. Subjects' choice reactions to letters at one level of information in a compound letter stimulus were impaired when letters at the other (irrelevant) level signified the opposite response. In the absence of differences in processing speed, global and local information produced symmetrical interference effects. Interference effects did vary, however, as a function of temporal advantage for the processing of information from either level. The individually faster level (be it global or local) interfered with the slower level but was itself relatively immune to such interference by the slower level. Analysis of event-related brain potentials and of the electromyogram revealed that incongruent irrelevant letters induced perceptual conflict but not response competition, thus pointing to a perceptual locus of processing dominance for the faster processed level of information in the compound stimulus.

Adolescent↗

PubMed1991

Graphical and statistical techniques for cardiac cycle time (phase) dependent changes in interbeat interval.

Cardiac cycle time effects refer to the relative lengthening or shortening of a single cardiac cycle as a function of when in the cycle brief sensorimotor events occur. These effects may provide short-latency measures of cardiac sensitivity to psychological events. Conventional representations have, however, failed to clearly separate changes in interbeat interval due to cycle time--i.e., phase dependent changes--from other types of change. This paper advocates a particular technique of plotting to solve these representation problems. Heartbeat timing is represented in real time and in the context of beats both preceding and following the event of interest. The plot, a phase-sensitive plot, conceptualizes phase-sensitive (cardiac cycle time) effects as a change in linear or higher order trend. Thus, an adaptation of trend analysis is proposed as an efficient statistical analysis that follows directly from the proposed representational technique.

Data Display↗