Numbers in action during cognitive flexibility – A neurophysiological approach on numerical operations underlying task switching

Cortical oscillations and event-related brain potentials during the preparation and execution of deceptive behavior

Deception often occurs in response to a preceding cue (e.g., a precarious question) alerting us about the need to subsequently lie. Here, we simulate this process by adapting a previously established paradigm of intentionally false responding, now instructing participants about the need for deception (vs. truthful responses) by means of a simple cue occurring before each response-relevant target. We analyzed event-related brain potentials (ERPs) as well as cortical oscillations recorded from the scalp. In an experimental study (N = 44), we show that a cue signaling the need for deception involves increased attentional selection (P2, P3a, P3b). Moreover, in the period following the cue and leading up to the target, ERP and oscillatory signatures of anticipation and preparation (Contingent Negative Variation, alpha suppression) were found to be increased during trials requiring a deceptive as compared to a truthful response. Additionally, we replicated earlier findings that target processing involves enhanced motivated attention toward words requiring a deceptive response (LPC). Moreover, a signature of integration effort and semantic inhibition (N400) was observed to be larger for words to which responses have to be intentionally false as compared to those to which responses must be truthful. Our findings support the view of the involvement of a series of basic cognitive processes (especially attention and cognitive control) when responses are deliberately wrong instead of right. Moreover, preceding cues signaling the subsequent need for lying already elicit attentional and preparatory mechanisms facilitating the cognitive operations necessary for later successful lying.

Functional Near-Infrared Spectroscopy Evidence of Prefrontal Regulation of Cognitive Flexibility in Adults With ADHD

BACKGROUND

Executive function (EF) deficit is considered to be a core cognitive deficit in ADHD. The current study combined functional near-infrared spectroscopy (fNIRS) and numerical switching tasks to investigate the cognitive flexibility of adult ADHD as an important part of EF.

MATERIAL AND METHODS

The Wender Utah Rating Scale and the adult ADHD self-rating scale were respectively used to assess ADHD symptoms in childhood and adulthood. A 22 adults with ADHD and 24 healthy controls (HCs) participated in the large/small and odd/even switching tasks.

RESULTS

Behavioral results were indicative of the ADHD switch costs being lower than the HCs. The fNIRS results also showed that ADHD's frontal eye field was over-activated both in magnitude and switched judgment tasks. The dorsolateral prefrontal cortex was also over-activated in magnitude judgment tasks.

CONCLUSION

These results revealed that adults with ADHD's cognitive flexibility performed better than the HCs, which result is different from mainstream ideas that EF is a core deficit in ADHD.

Cognitive control in number processing: new evidence from number compatibility effects in task-switching

A growing body of research suggests that basic numerical abilities such as number magnitude processing are influenced by cognitive control processes. So far, evidence for number processing being affected by cognitive control processes stems primarily from observed adaptations of numerical effects to stimulus set characteristics (e.g. order or ratio of specific stimulus types). Complementing previous research on adaptation to stimulus set characteristics as an index of influences of cognitive control, the present study employed a task-switching paradigm to examine how cognitive control processes influence number processing. Participants were presented with a two-digit number and had to either judge its parity or compare its magnitude to a standard depending on a preceding cue. We expected numerical congruency effects (i.e. the unit-decade compatibility effect for magnitude comparisons and the parity congruity effect for parity judgements) to be larger in switch trials, as persisting activation of the task set of the preceding trial should increase interference. In contrast to our expectations, both numerical congruity effects were reduced following task switches as compared to repetitions. This interaction of task-switching with numerical congruency effects suggests an influence of cognitive control on basic number processing in form of persisting inhibition of previously abandoned task sets, so that these exert less influence on current number processing demands.

Atypical Neural Responses of Cognitive Flexibility in Parents of Children With Autism Spectrum Disorder

Impaired cognitive flexibility has been repeatedly demonstrated in autism spectrum disorder (ASD). There is strong evidence for genetic involvement in ASD. First-degree relatives of individuals with ASD may show mild deficits in cognitive inflexibility. The present study investigated cognitive flexibility and its neuroelectrophysiological mechanisms in first-degree relatives of individuals with ASD to assess its potential familiality. Forty-five biological parents of individuals/children with ASD (pASD) and thirty-one biological parents of typically developing individuals/children (pTD), matched by gender, age, and IQ, were enrolled. The broad autism phenotype questionnaire (BAPQ) and cognitive flexibility inventory (CFI) were used to quantitatively assess autistic traits and cognitive flexibility in daily life, respectively. The task-switching paradigm was used to evaluate the behavioral flexibility in a structured assessment situation. Event-related potentials (ERPs) induced by this paradigm were also collected. Results showed that compared with the pTD group, the pASD group had lower CFI scores (t = −2.756, p < 0.01), while both groups showed an equivalent “switch cost” in the task-switching task (p > 0.05). Compared with the pTD group, the pASD group induced greater N2 amplitude at F3, F4, Fz, and C4 (F = 3.223, p < 0.05), while P3 amplitude and latency did not differ between the two groups. In addition, there was a significant negative correlation between the CFI total scores and BAPQ total scores in the pASD group (r = −0.734, p < 0.01). After controlling for age and IQ, the N2 amplitude in the frontal lobe of pASD was negatively correlated with the CFI total scores under the repetition sequence (r = −0.304, p = 0.053). These results indicated that pASD had deficit in cognitive flexibility at the self-reported and neurological levels. The cognitive flexibility difficulties of parents of children with ASD were related to autistic traits. These findings support that cognitive flexibility is most likely a neurocognitive endophenotype of ASD, which is worthy of further investigation.

Multi-level decoding of task sets in neurophysiological data during cognitive flexibility

Cognitive flexibility is essential to achieve higher level goals. Cognitive theories assume that the activation/deactivation of goals and task rules is central to understand cognitive flexibility. However, how this activation/deactivation dynamic is implemented on a neurophysiological level is unclear. Using EEG-based multivariate pattern analysis (MVPA) methods, we show that activation of relevant information occurs parallel in time at multiple levels in the neurophysiological signal containing aspects of stimulus-related processing, response selection, and motor response execution, and relates to different brain regions. The intensity with which task sets are activated and processed dynamically decreases and increases. The temporal stability of these activations could, however, hardly explain behavioral performance. Instead, task set deactivation processes associated with left orbitofrontal regions and inferior parietal regions selectively acting on motor response task sets are relevant. The study shows how propositions from cognitive theories stressing the importance task set activation/deactivation during cognitive flexibility are implemented on a neurophysiological level.

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Stimulus-related, motor, and response selection aspects of task set were decoded

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Activation of task rule information occurs at multiple neurophysiological levels

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Activation and deactivation of rule sets contributes to cognitive flexibility

Task Switching and the Role of Motor Reprogramming in Parietal Structures

Human behaviour amazes with extraordinary flexibility and the underlying neural mechanisms have often been studied using task switching. Despite extensive research, the relative importance of "cognitive" and "motor" aspects during switching is unclear. In the current study we examine this question combining EEG analysis techniques and source localization to examine whether the selection of the response, or processes during the execution of the response, contribute most to switching effects. A clear dissociation was observed in the signal decomposition, since codes relating to motor aspects play a significant role in task switching and the scope of the switching costs. This was not the case for signals that denote reaction selection or decision processes that respond to selection or basic stimulus processing codes. On a functional neuroanatomical level, these modulations in motor processes showed a clear temporal sequence in that motor codes are processed primarily in superior parietal regions (Brodman area 7) and only then in premotor regions (Brodman area 6). The observed modulations may reflect motor reprogramming processes. The study shows how EEG signal analysis in combination with brain mapping methods can inform debates on theories of human cognitive flexibility.

More change in task repetition, less cost in task switching: Behavioral and event-related potential evidence

Previous studies have shown that the probability of task switching can vary the level of cognitive control and modulate the size of switch costs. However, it is unclear whether switch costs would be affected by a task-repetition context formed by varying the degree of response (and task-relevant stimulus property) change within the task repetition sequences while the probability of task switching remains constant. In the present study, participants were presented with a string of digits (e.g., ②②②). Basing on stimulus color, they were required to indicate either the presented digit, or the number of presented digits. Before task switching, stimulus and response in consecutive task-repeat trials varied more or less frequently. Behavioral results showed that the frequent-change context elicited smaller switch costs than the rare-change context. Event-related potential (ERP) results indicated that: (1) the frequent-change context evoked greater fronto-central N2 amplitudes for both task-repeat and task-switch trials, implying that cognitive control increased due to the variation of stimulus and response associations; (2) for the task switch trials, smaller P300 amplitudes were evoked in the frequent-change context than the rare-change context, reflecting the promoted task-set reconfiguration. These findings suggest that, the more change in stimulus and response during task repetition, the higher the overall level of cognitive control and the higher efficiency of task-switching.