Friederike Schlaghecken

Interference tasks combining different distractor types usually find that between-trial adaptations (congruency sequence effects [CSEs]) do not interact with each other, suggesting that sensorimotor control is domain-specific. However, within each trial, different distractor types often do interact, suggesting that control is domain-general. The present study presents a solution to this apparent paradox. In 3 experiments, testing 130 participants in total, we (a) confirm the simultaneous presence of between-trial domain-specific (noninteracting) CSEs and within-trial "domain-general" interactions in a fully factorial hybrid prime-Simon design free of repetition or contingency confounds; (b) demonstrate that the within-trial interaction occurs with supraliminal, but not with subliminal primes; and (c) show that it is disproportionately enlarged in older adults. Our findings suggest that whereas interference (priming and Simon) effects and CSEs reflect direct sensorimotor control, the within-trial interaction does not reflect sensorimotor control but "confusion" at higher-level processing stages (reactivation aversion effect [RAE]).

Aim: The effect of cognitive activity on human metabolic rate is incompletely understood. To investigate changes in human metabolism during periods of cognitive demand, we measured the effect of simple cognitive activity on energy expenditure during a cognitive task. Methods: Nine healthy volunteers participated in a simple cognitive-motor task with both response priming and neutral (non-response priming) conditions, enabling assessment of cognitive interference. Energy expenditure was measured during repeated alternating test and rest phases, lasting approximately 2 minutes each. Results: Energy expenditure (EE) was significantly greater during test than during rest phases (mean EE=29.1 kcal/kg/d, SE=1.24 vs 25.1 kcal/kg/d, SE=1.19), F(3, 18)=8.18, p=0.029. Following each test phase, energy expenditure initially continued to rise (‘rebound spike’) before dropping rapidly. Rebound spikes showed significantly larger peaks following priming than following neutral cognitive-motor test phases. Conclusion: We demonstrate for the first time that overall energy expenditure is influenced by simple cognitivemotor tasks in healthy human participants. We provide proof of concept that indirect calorimetry is a sufficiently sensitive measure to detect even subtle difference in cognitive demands (interference versus non-interference) between tasks with identical response demands (speeded left and right key-presses).

Reports an error in "Age-related deficits in low-level inhibitory motor control" by Friederike Schlaghecken, Kulbir S. Birak and Elizabeth A. Maylor (Psychology and Aging, 2011[Dec], Vol 26[4], 905-918). The authors discovered that the method proposed for individually extracting priming effects from time course analysis may lead to some spurious effects. In view of possible spurious effects from their application of time course analysis, the authors adopted an alternative strategy that retains their attempt to take an individual approach to identifying NCEs in older participants who may vary more than young participants in terms of the prime-target SOA at which NCEs initially appear. This reanalysis is presented in the erratum. (The following abstract of the original article appeared in record 2011-10375-001.) Inhibitory control functions in old age were investigated with the "masked prime" paradigm in which participants executed speeded manual choice responses to simple visual targets. These were preceded-either immediately or at some earlier time-by a backward-masked prime. Young adults produced positive compatibility effects (PCEs)-faster and more accurate responses for matching than for nonmatching prime-target pairs-when prime and target immediately followed each other, and the reverse effect (negative compatibility effect, NCE) for targets that followed the prime after a short interval. Older adults produced similar PCEs to young adults, indicating intact low-level motor activation, but failed to produce normal NCEs even with longer delays (Experiment 1), increased opportunity for prime processing (Experiment 2), and prolonged learning (Experiment 3). However, a fine-grained analysis of each individual's time course of masked priming effects revealed NCEs in the majority of older adults, of the same magnitude as those of young adults. These were significantly delayed (even more than expected on the basis of general slowing), indicating a disproportionate impairment of low-level inhibitory motor control in old age. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Even at subclinical levels, anxiety and depression are associated with impaired cognitive control. It is unclear, though, to what extent these deficits reflect a common underlying dysfunction. Using a non-affective hybrid masked prime-Simon task, we obtained several measures of within- and between- trial inhibitory behavioral control in 80 young, healthy volunteers, together with measures of their anxiety and depression levels. Neither depression nor anxiety affected low-level within-trial control, or any of the between-trial control measures. However, increased levels of depression, but not of anxiety, were associated with impaired high-level within-trial control (increased Simon effect). Results indicate that depression, but not anxiety, impairs voluntary online response-control mechanisms independent of affective content.

In a masked prime task using a 0-ms prime-target inter-stimulus-interval, responses on compatible trials (prime and target match) are usually faster and more accurate than responses on incompatible trials (prime-target mismatch). This positive compatibility effect comprises benefits on compatible relative to neutral trials and costs on incompatible relative to neutral trials. Comparing performance in 2- vs. 4-alternative-response versions of the task indicates that benefits are due to direct priming of a motor response, whereas costs reflect inhibition of the alternative response tendency. The present study investigates whether normal aging is associated with a selective deficit in the inhibitory component, affecting both low-level motor and higher-level executive control. Testing 20 young and 20 older adults, we found that (a) overall, prime-induced benefits were of similar magnitude across age groups, but inhibition-based costs were smaller in older compared to young adults; (b) increasing the number of response alternatives caused the same pattern of unaltered benefits and reduced costs in both age groups; and (c) costs, but not benefits, in the 2-alternative condition were significantly predicted by scores on the digit-symbol substitution task (DSST), independently of age and other background variables. Results demonstrate the possibility of isolating an inhibitory component in low-level perceptuo-motor control. Importantly, this component shows an age-related decline in the absence of a corresponding decline of visuo-motor excitability, and appears to be linked to performance on a higher-level processing speed task. We hypothesize that aging might affect the brain's ability to establish precise short-term lateral inhibitory links, and that even in young adults, the efficiency of such links is a significant contributing factor in higher-level cognitive performance.

Theories of cognitive control generally assume that perceived conflict acts as a signal to engage inhibitory mechanisms that suppress subsequent conflicting information. Crucially, an absence of conflict is not regarded as being a relevant signal for cognitive control. Using a cueing, a priming, and a Simon task, we provide evidence that conflict does not have this unique signal status: Encountering a conflict does not lead to behavioral adjustments on subsequent conflict trials, whereas encountering a nonconflict trial does lead to behavioral adjustments on subsequent nonconflict trials. We propose that this apparent role-reversal can be explained by a mechanism that responds to both the presence and the absence of conflict, down-regulating the visuomotor system following conflict, and up-regulating it following nonconflict.

To examine age-related effects on high-level consciously controlled and low-level automatically controlled inhibitory processes, the Simon task was combined with the masked prime task in a hybrid procedure. Young and older adults responded to the identity of targets (left/right key-press to left-/right-pointing arrows) that appeared on the left/right of the screen and were preceded by left-/right-pointing backward-masked arrow primes at fixation. Responses were faster and more accurate when the target was congruent with its location than incongruent (Simon effect), and when the target was incompatible with the prime than compatible (negative compatibility effect; NCE). The Simon effect was disproportionately larger, and the NCE disproportionately delayed, in older adults compared to young adults, indicating both high- and low-level inhibitory control deficits with aging. Moreover, the two effects were additive in young adults, but interactive in older adults, providing support for the dedifferentiation hypothesis of aging. Specifically, older adults’ prime-related inhibitory control appeared improved on incongruent relative to congruent trials, suggesting that impaired automatic control was substituted by high-level, non-automatic processes.

Cognitive control resolves conflicts between appropriate and inappropriate response tendencies. Is this achieved by a unitary all-purpose conflict control system, or do independent subsystems deal with different aspects of conflicting information? In a fully factorial hybrid prime-Simon task, participants responded to the identity of targets displayed at different nominally irrelevant screen locations, preceded by nominally irrelevant, consciously or nonconsciously perceived primes. The response required by the target's identity could match or mismatch (a) the target's location, and (b) the prime's identity, resulting in potential conflict (a) across and (b) within stimulus domains. Conflict effects were investigated within and across trials. Results suggest that (i) nonconsciously perceived information elicits within-trial control, but--unlike consciously perceived information--no across-trial behavioral modulation; (ii) separate subsystems deal with conflicts arising from different stimulus domains; and (iii) occasional apparent interactions between domains reflect a particular difficulty in reactivating a just-discarded response (reactivation aversion effect, RAE).