Higher-order Control Processes Research Articles

The Effects of Reinforcing Task Alternations on Voluntary Task Selection

Everyday life often requires us to switch between states of cognitive flexibility and stability. However, little is known about what drives their regulation at the meta-control level. Based on current theories of cognitive control, we tested whether the regulation of cognitive flexibility and stability is guided by reinforcement learning. Using a task-switching paradigm with a double registration procedure – where people need to choose which task to perform before seeing the target, we systematically reinforced cued task switches or repetitions to test whether this led to more voluntary task switching (flexibility) or repeating (stability) on interspersed unrewarded free choice trials, respectively. While we did not find the hypothesized effect in an uninstructed version of the experiment (n=97), informing participants (n=58) on the reinforcement schedule on cued trials induced more switching or repeating on unrewarded free-choice trials. We speculate that people adapt their control strategies if they are aware of the respective benefits, even when they cease to be rewarded. Interestingly, choices were predominantly driven by task preference in both experiments and strongly correlated with task performance costs. This finding suggests that, when using an interspersed design with a double registration procedure, people mostly choose tasks based on task difficulty rather than switch avoidance. Together, these experiments help determine whether and when people can learn about the value of task selection strategies beyond the scope of a single task, and provide a self-regulating system to understand putative higher-order control processes.

Computational Mechanisms Mediating Inhibitory Control of Coordinated Eye-Hand Movements.

Significant progress has been made in understanding the computational and neural mechanisms that mediate eye and hand movements made in isolation. However, less is known about the mechanisms that control these movements when they are coordinated. Here, we outline our computational approaches using accumulation-to-threshold and race-to-threshold models to elucidate the mechanisms that initiate and inhibit these movements. We suggest that, depending on the behavioral context, the initiation and inhibition of coordinated eye-hand movements can operate in two modes—coupled and decoupled. The coupled mode operates when the task context requires a tight coupling between the effectors; a common command initiates both effectors, and a unitary inhibitory process is responsible for stopping them. Conversely, the decoupled mode operates when the task context demands weaker coupling between the effectors; separate commands initiate the eye and hand, and separate inhibitory processes are responsible for stopping them. We hypothesize that the higher-order control processes assess the behavioral context and choose the most appropriate mode. This computational mechanism can explain the heterogeneous results observed across many studies that have investigated the control of coordinated eye-hand movements and may also serve as a general framework to understand the control of complex multi-effector movements.

Neuroanatomical alterations in higher-order thalamic nuclei of fetuses with Down syndrome

ObjectivesDown syndrome (DS) is a genetic condition characterized by cognitive disability starting from infancy. Children with DS exhibit deficits in several cognitive domains, including executive function, i.e., a set of cognitive processes that heavily depend on higher-order thalamic nuclei. The goal of this study was to establish whether executive function-related thalamic nuclei of fetuses with DS exhibit neuroanatomical alterations that may contribute to the defects in higher-order control processes seen in children with DS. Patients and MethodsIn brain sections from fetuses with DS and control fetuses (gestational week 17–22), we evaluated the cellularity in the mediodorsal nucleus (MD), the centromedian nucleus (CM), and the parafascicular nucleus (PF) of the thalamus and the density of proliferating cells in the third ventricle. ResultsWe found that all three nuclei had a notably reduced cell density. This defect was associated with a reduced density of proliferating cells in the third ventricle, suggesting that the reduced cellularity in the MD, CM, and PF of fetuses with DS was due to neurogenesis impairment. The separate evaluation of projection neurons and interneurons in the MD, CM, and PF showed that in fetuses with DS the density of projection neurons was reduced, with no changes in interneuron density. ConclusionThis study provides novel evidence for DS-linked cellularity alterations in the MD, CM, and PF and suggests that altered signal processing in these nuclei may be involved in the impairment in higher-order control processes observed in individuals with DS starting from infancy.

Motor skills in kindergarten: Internal structure, cognitive correlates and relationships to background variables

The present study aimed to contribute to the discussion about the relation between motor coordination and executive functions in preschool children. Specifically, the relation between gross and fine motor skills and executive functions as well as the relation to possible background variables (SES, physical activity) were investigated. Based on the data of N=156 kindergarten children the internal structure of motor skills was investigated and confirmed the theoretically assumed subdivision of gross and fine motor skills. Both, gross and fine motor skills correlated significantly with executive functions, whereas the background variables seemed to have no significant impact on the executive functions and motor skills. Higher order control processes are discussed as an explanation of the relation between executive functions and motor skills.

Executive functions disorders in high functioning autism and rehabilitation implications

IntroductionThe term executive functions (EFs) includes a set of cognitive processes such as planning, working memory, attention, problem solving, inhibition, mental flexibility, multi-tasking, and initiation and monitoring of actions. EFs are the higher order control processes to guide behaviour.Some studies on the relationship between EFs and autism spectrum disorder (ASD) showed deficit in the cognitive flexibility and speed processing, particularly with Asperger syndrome. Recently, Merchán-Naranjo et al. [1] supported that children's and adolescents with autism without intellectual disability are insufficient in at least 5 domains: attention, working memory, cognitive flexibility, inhibitory control and problem-solving.AimsOur work is aimed at verifying if the presence of a dysexecutive syndrome significantly impacts on the adaptive functioning of people with high functioning autism.MethodsA group of young adults with ASD were administered traditional neuropsychological assessment, specific assessment, focusing on the planning strategies for solving problems (Test Tower of London), abstraction and categorization (Wisconsin Card Sorting Test), and the Dysexecutive Questionnaires.ResultsThe results showed the presence of a specific deficit in the executive functioning in an average cognitive functioning.ConclusionsIntegrate the standard cognitive screening with a specific EFs assessment resulted to be very useful for the clinician to realize neuropsychological and psychotherapeutic individualized treatment.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults - A Pilot Study.

Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination.

The Parallel Episodic Processing (PEP) model 2.0: A single computational model of stimulus-response binding, contingency learning, power curves, and mixing costs

The current paper presents an extension of the Parallel Episodic Processing model. The model is developed for simulating behaviour in performance (i.e., speeded response time) tasks and learns to anticipate both how and when to respond based on retrieval of memories of previous trials. With one fixed parameter set, the model is shown to successfully simulate a wide range of different findings. These include: practice curves in the Stroop paradigm, contingency learning effects, learning acquisition curves, stimulus-response binding effects, mixing costs, and various findings from the attentional control domain. The results demonstrate several important points. First, the same retrieval mechanism parsimoniously explains stimulus-response binding, contingency learning, and practice effects. Second, as performance improves with practice, any effects will shrink with it. Third, a model of simple learning processes is sufficient to explain phenomena that are typically (but perhaps incorrectly) interpreted in terms of higher-order control processes. More generally, we argue that computational models with a fixed parameter set and wider breadth should be preferred over those that are restricted to a narrow set of phenomena.

Feature Integration and Task Switching: Diminished Switch Costs after Controlling for Stimulus, Response, and Cue Repetitions.

This report presents data from two versions of the task switching procedure in which the separate influence of stimulus repetitions, response key repetitions, conceptual response repetitions, cue repetitions, task repetitions, and congruency are considered. Experiment 1 used a simple alternating runs procedure with parity judgments of digits and consonant/vowel decisions of letters as the two tasks. Results revealed sizable effects of stimulus and response repetitions, and controlling for these effects reduced the switch cost. Experiment 2 was a cued version of the task switch paradigm with parity and magnitude judgments of digits as the two tasks. Results again revealed large effects of stimulus and response repetitions, in addition to cue repetition effects. Controlling for these effects again reduced the switch cost. Congruency did not interact with our novel “unbiased” measure of switch costs. We discuss how the task switch paradigm might be thought of as a more complex version of the feature integration paradigm and propose an episodic learning account of the effect. We further consider to what extent appeals to higher-order control processes might be unnecessary and propose that controls for feature integration biases should be standard practice in task switching experiments.

Task switching and action sequencing

We investigated if task switching affects late response processes that occur after the selection of a response. Subjects performed a sequence of two responses. The first and second response were selected, and then executed in close succession. The interresponse interval (IRI) was taken as a measure of late response processes. The two responses could either belong to different tasks (task-switch condition), or to the same task that was performed twice (task-repetition condition). In all three experiments, the IRI was found to be longer in the task-switch condition than in the task-repetition condition, consistent with the idea that task switching affected late response processes. However, the effects of the manipulation of the stimulus-onset asynchrony revealed that the tendency to perform the two responses as a sequence was reduced in the task-switch condition relative to the task-repetition condition. Thus, the data do not provide unequivocal evidence for task switching affecting late response processes. The data show, however, that task switching affected action sequencing. Two actions that do not belong to the same task context are less likely to be performed as an action sequence. We suggest that task switching interacts with higher-order control processes that cannot be studied within the traditional task-switching paradigm.

Lateral prefrontal cortex: architectonic and functional organization

A comparison of the architecture of the human prefrontal cortex with that of the macaque monkey showed a very similar architectonic organization in these two primate species. There is no doubt that the prefrontal cortical areas of the human brain have undergone considerable development, but it is equally clear that the basic architectonic organization is the same in the two species. Thus, a comparative approach to the study of the functional organization of the primate prefrontal cortex is more likely to reveal the essential aspects of the various complex control processes that are the domain of frontal function. The lateral frontal cortex appears to be functionally organized along both a rostral-caudal axis and a dorsal-ventral axis. The most caudal frontal region, the motor region on the precentral gyrus, is involved in fine motor control and direct sensorimotor mappings, whereas the caudal lateral prefrontal region is involved in higher order control processes that regulate the selection among multiple competing responses and stimuli based on conditional operations. Further rostrally, the mid-lateral prefrontal region plays an even more abstract role in cognitive control. The mid-lateral prefrontal region is itself organized along a dorsal-ventral axis of organization, with the mid-dorsolateral prefrontal cortex being involved in the monitoring of information in working memory and the mid-ventrolateral prefrontal region being involved in active judgments on information held in posterior cortical association regions that are necessary for active retrieval and encoding of information.