The role of task-related learned representations in explaining asymmetries in task switching

Effectiveness of Digital Cognitive Behavior Therapy for the Treatment of Insomnia: Spillover Effects of dCBT

The effects of digital Cognitive Behavior Therapy for insomnia (dCBT-i) on sleep quality have been previously demonstrated but the spillover effects on fatigue, flow (a state of immersion in activities of interest), and cognitive flexibility remain unclear. The current study examined the effectiveness of dCBT-i. A total of 97 college students (20.96 ± 1.87 years, 73.1% female students) were randomly selected from a shortlist and divided into sleep intervention (n = 39), conventional education (n = 37), and healthy control (n = 21) groups. Task switching paradigm, Fatigue Severity Scale (FSS), Flow Experience Scale (FES), and the Chinese version of the Pittsburgh Sleep Quality Index (CPSQI) were measured pre- and post-intervention. Results show that the sleep quality of the intervention group improved, and fatigue was relieved. Participants in the sleep intervention group had increased flow experience scores post-intervention and improved cognitive flexibility. The control group’s sleep quality deteriorated and fatigue level increased. dCBT-i can not only achieve a significant improvement in sleep quality and reduce fatigue, but also improve learning abilities, quality of life, flow, and cognitive flexibility. Future research should pay attention to indicators such as work efficiency, sedative use, and the durability and stability of such effects.

An Anticipatory Circuit Modification That Modifies Subsequent Task Switching

Modulators are generally expected to establish a network configuration that is appropriate for the current circumstances. We characterize a situation where the opposite is apparently observed. A network effect of a peptide modulator is counterproductive in that it tends to impede rather than promote the creation of the configuration that is appropriate when the modulator is released. This raises a question: why does release occur? We present data that strongly suggest that it impacts task switching. Our experiments were conducted in an Aplysia feeding network that generates egestive and ingestive motor programs. Initial experiments focused on egestive activity and the neuron B8. As activity becomes egestive, there is an increase in synaptic drive to B8 and its firing frequency increases (Wang et al., 2019). We show that, as this occurs, there is also a persistent current that develops in B8 that is outward rather than inward. Dynamic clamp introduction of this current decreases excitability. When there is an egestive-ingestive task switch in Aplysia, negative biasing is observed (i.e., a bout of egestive activity has a negative impact on a subsequent attempt to initiate an ingestive response) (Proekt et al., 2004). Using an in vitro analog of negative biasing, we demonstrate that the outward current that develops during egestive priming plays an important role in establishing this phenomenon. Our data suggest that, although the outward current induced as activity becomes egestive is counterproductive at the time, it plays an anticipatory role in that it subsequently impacts task switching.SIGNIFICANCE STATEMENT In this study, we identify a peptide-induced circuit modification (induction of an outward current) that does not immediately promote the establishment of a behaviorally appropriate network configuration. We ask why this might occur, and present data that strongly suggest that it plays an important role during task switching. Specifically, our data suggest that the outward current we characterize plays a role in the negative biasing that is seen in the mollusc Aplysia when there is a transition from egestive to ingestive activity. It is possible that the mechanism that we describe operates in other species. A negative effect of egestion on subsequent ingestion is observed throughout the animal kingdom.

The difference in the warning effect of different warning signs

Introduction. Warning signs play a very important role in safeguarding life and property in dangerous situations. Previous studies have mainly focused on the physical properties of warning signs, and few studies have been conducted on the different types. Methods. In Experiment 1, the oddball paradigm and the go/no-go paradigm were used to study the warning effect of different types of warning signs. In Experiment 2, the dual-task paradigm was adopted. Results. In Experiment 1, the results showed that a warning sign with text as content had the worst warning effect, followed by the combination of image and text, and a warning sign with an image as content had the best warning effect. In Experiment 2, it was found that different types of warning signs would have different effects on the performance of the secondary task. Conclusions. The reason for this may be the different processing methods used for text and image. Therefore, in dangerous situations that require a quick response, simple and understandable graphics should be used as the content of warning signs. In complex circumstances, it may be necessary to use a combination of image and text for warning sign content.

An Experimenter's Influence on Motor Enhancements: The Effects of Letter Congruency and Sensory Switch-Costs on Multisensory Integration

Multisensory integration can alter information processing, and previous research has shown that such processes are modulated by sensory switch costs and prior experience (e.g., semantic or letter congruence). Here we report an incidental finding demonstrating, for the first time, the interplay between these processes and experimental factors, specifically the presence (vs. absence) of the experimenter in the testing room. Experiment 1 demonstrates that multisensory motor facilitation in response to audiovisual stimuli (circle and tone with no prior learnt associations) is higher in those trials in which the sensory modality switches than when it repeats. Those participants who completed the study while alone exhibited increased RT variability. Experiment 2 replicated these findings using the letters “b” and “d” presented as unisensory stimuli or congruent and incongruent multisensory stimuli (i.e., grapheme-phoneme pairs). Multisensory enhancements were inflated following a sensory switch; that is, congruent and incongruent multisensory stimuli resulted in significant gains following a sensory switch in the monitored condition. However, when the participants were left alone, multisensory enhancements were only observed for repeating incongruent multisensory stimuli. These incidental findings therefore suggest that the effects of letter congruence and sensory switching on multisensory integration are partly modulated by the presence of an experimenter.

Task intentions and their implementation into actions: cognitive control from adolescence to middle adulthood

Cognitive control processes involved in human multitasking arise, mature, and decline across age. This study investigated how age modulates cognitive control at two different levels: the level of task intentions and the level of the implementation of intentions into the corresponding actions. We were particularly interested in specifying maturation of voluntary task choice (intentions) and task-switching execution (their implementations) between adolescence and middle adulthood. Seventy-four participants were assigned to one of the four age groups (adolescents, 12-17 years; emerging adults, 18-22 years; young adults, 23-27 years; middle-aged adults, 28-56 years). Participants chose between two simple cognitive tasks at the beginning of each trial before pressing a spacebar to indicate that the task choice was made. Next, a stimulus was presented in one of the three adjacent boxes, with participants identifying either the location or the shape of the stimulus, depending on their task choice. This voluntary task-switching paradigm allowed us to investigate the intentional component (task choice) separately from its implementation (task execution). Although all participants showed a tendency to repeat tasks more often than switching between them, this repetition bias was significantly stronger in adolescents than in any adult group. Furthermore, participants generally responded slower after task switches than after task repetitions. This switch cost was similar across tasks in the two younger groups but larger for the shape than the location task in the two older groups. Together, our results demonstrate that both task intentions and their implementation into actions differ across age in quite specific ways.

Understanding Behavioural Rigidity in Autism Spectrum Conditions: The Role of Intentional Control

Although behavioural rigidity belongs to the core symptoms of autism spectrum conditions, little is known about its underlying cognitive mechanisms. The current study investigated the role of intentional control mechanisms in behavioural rigidity in autism. Autistic individuals and their matched controls were instructed to repeatedly choose between two simple cognitive tasks and to respond accordingly to the subsequently presented stimulus. Results showed that autistic participants chose to repeat tasks more often than their controls and when choosing to switch, they demonstrated larger performance costs. These findings illustrate that when required to make their own choices, autistic people demonstrate rigidity at different performance levels, suggesting that intentional control mechanisms might be important for a better understanding of behavioural rigidity in autism.

An Increase in Postural Load Facilitates an Anterior Shift of Processing Resources to Frontal Executive Function in a Postural-Suprapostural Task

Increase in postural-demand resources does not necessarily degrade a concurrent motor task, according to the adaptive resource-sharing hypothesis of postural-suprapostural dual-tasking. This study investigated how brain networks are organized to optimize a suprapostural motor task when the postural load increases and shifts postural control into a less automatic process. Fourteen volunteers executed a designated force-matching task from a level surface (a relative automatic process in posture) and from a stabilometer board while maintaining balance at a target angle (a relatively controlled process in posture). Task performance of the postural and suprapostural tasks, synchronization likelihood (SL) of scalp EEG, and graph-theoretical metrics were assessed. Behavioral results showed that the accuracy and reaction time of force-matching from a stabilometer board were not affected, despite a significant increase in postural sway. However, force-matching in the stabilometer condition showed greater local and global efficiencies of the brain networks than force-matching in the level-surface condition. Force-matching from a stabilometer board was also associated with greater frontal cluster coefficients, greater mean SL of the frontal and sensorimotor areas, and smaller mean SL of the parietal-occipital cortex than force-matching from a level surface. The contrast of supra-threshold links in the upper alpha and beta bands between the two stance conditions validated load-induced facilitation of inter-regional connections between the frontal and sensorimotor areas, but that contrast also indicated connection suppression between the right frontal-temporal and the parietal-occipital areas for the stabilometer stance condition. In conclusion, an increase in stance difficulty alters the neurocognitive processes in executing a postural-suprapostural task. Suprapostural performance is not degraded by increase in postural load, due to (1) increased effectiveness of information transfer, (2) an anterior shift of processing resources toward frontal executive function, and (3) cortical dissociation of control hubs in the parietal-occipital cortex for neural economy.

Repetition priming of motor activity mediated by a central pattern generator: the importance of extrinsic vs. intrinsic program initiators

Repetition priming is characterized by increased performance as a behavior is repeated. Although this phenomenon is ubiquitous, mediating mechanisms are poorly understood. We address this issue in a model system, the feeding network of Aplysia This network generates both ingestive and egestive motor programs. Previous data suggest a chemical coding model: ingestive and egestive inputs to the feeding central pattern generator (CPG) release different modulators, which act via different second messengers to prime motor activity in different ways. The ingestive input to the CPG (neuron CBI-2) releases the peptides feeding circuit activating peptide and cerebral peptide 2, which produce an ingestive pattern of activity. The egestive input to the CPG (the esophageal nerve) releases the peptide small cardioactive peptide. This model is based on research that focused on a single aspect of motor control (radula opening). Here we ask whether repetition priming is observed if activity is triggered with a neuron within the core CPG itself and demonstrate that it is not. Moreover, previous studies demonstrated that effects of modulatory neurotransmitters that induce repetition priming persist. This suggests that it should be possible to "prime" motor programs triggered from within the CPG by first stimulating extrinsic modulatory inputs. We demonstrate that programs triggered after ingestive input activation are ingestive and programs triggered after egestive input activation are egestive. We ask where this priming occurs and demonstrate modifications within the CPG itself. This arrangement is likely to have important consequences for "task" switching, i.e., the cessation of one type of motor activity and the initiation of another.

Self-control depletion in tufted capuchin monkeys (Sapajus spp.): does delay of gratification rely on a limited resource?

Self-control failure has enormous personal and societal consequences. One of the most debated models explaining why self-control breaks down is the Strength Model, according to which self-control depends on a limited resource. Either previous acts of self-control or taking part in highly demanding cognitive tasks have been shown to reduce self-control, possibly due to a reduction in blood glucose levels. However, several studies yielded negative findings, and recent meta-analyses questioned the robustness of the depletion effect in humans. We investigated, for the first time, whether the Strength Model applies to a non-human primate species, the tufted capuchin monkey. We tested five capuchins in a self-control task (the Accumulation task) in which food items were accumulated within individual’s reach for as long as the subject refrained from taking them. We evaluated whether capuchins’ performance decreases: (i) when tested before receiving their daily meal rather than after consuming it (Energy Depletion Experiment), and (ii) after being tested in two tasks with different levels of cognitive complexity (Cognitive Depletion Experiment). We also tested, in both experiments, how implementing self-control in each trial of the Accumulation task affected this capacity within each session and/or across consecutive sessions. Repeated acts of self-control in each trial of the Accumulation task progressively reduced this capacity within each session, as predicted by the Strength Model. However, neither experiencing a reduction in energy level nor taking part in a highly demanding cognitive task decreased performance in the subsequent Accumulation task. Thus, whereas capuchins seem to be vulnerable to within-session depletion effects, to other extents our findings are in line with the growing body of studies that failed to find a depletion effect in humans. Methodological issues potentially affecting the lack of depletion effects in capuchins are discussed.

The role of emotional engagement and mood valence in retrieval fluency of mood incongruent autobiographical memory

Background: Retrieval of opposite mood autobiographical memories serves emotion regulation, yet the factors influencing this ability are poorly understood.

Methods: Three studies examined the effect of mood valence (sad vs. happy) and degree of emotional engagement on fluency of mood incongruent retrieval by manipulating emotional engagement and examining the effect of emotional film clips on the Fluency of Autobiographical Memory task.

Results: Following both sad and happy film clips, participants who received emotionally engaging instructions exhibited a greater recall latency of the first opposite mood memory, and had generated less such memories than those receiving emotionally disengaging instructions (Studies 1 and 2). A happy mood induction resulted in recollection of fewer mood incongruent memories compared to a sad mood induction. Providing emotionally engaging instructions was found to specifically hinder mood incongruent retrieval, without impairing mood congruent retrieval (Study 3).

Conclusion: High emotional engagement seems to impair the retrieval of mood incongruent memories. Being in a happy mood may also partially impair such retrieval. Implications regarding emotional regulation are discussed.