Associative Visuomotor Learning Using Transcranial Magnetic Stimulation Induces Stimulus-Response Interference.

Classical conditioning states that the systematic co-occurrence of a neutral stimulus with an unconditioned stimulus can cause the neutral stimulus to, over time, evoke the same response as the unconditioned stimulus. On a neural level, Hebbian learning suggests that this type of learning occurs through changes in synaptic plasticity when two neurons are simultaneously active, resulting in increased connectivity between them. Inspired by associative learning theories, we here investigated whether the mere co-activation of visual stimuli and stimulation of the primary motor cortex using TMS would result in stimulus-response associations that can impact future behavior. During a learning phase, we repeatedly paired the presentation of a specific color (but not other colors) with a TMS pulse over the motor cortex. Next, participants performed a two-alternative forced-choice task where they had to categorize simple shapes and we studied whether the shapes' task-irrelevant color (and its potentially associated involuntary motor activity) affected the required motor response. Participants showed more errors on incongruent trials for stimuli that were previously paired with high intensity TMS pulses, but only when tested on the same day. Using a drift diffusion model for conflict tasks, we further demonstrate that this interference occurred early, and gradually increased as a function of associated TMS intensity. Taken together, our findings show that the human brain can learn stimulus-response associations using externally induced motor cortex stimulation. Although we were inspired by the Hebbian learning literature, future studies should investigate whether Hebbian or other learning processes were also what brought about this effect.

The impact of free will beliefs on implicit learning.

A growing number of studies demonstrate that belief in free will (FWB) is dynamic, and can be reduced experimentally. Most of these studies assume that doing so has beneficial effects on behavior, as FWBs are thought to subdue unwanted automatic processes (e.g. racial stereotypes). However, relying on automatic processes can sometimes be advantageous, for instance during implicit learning (e.g. detecting and exploiting statistical regularities in the environment). In this registered report, we tested whether experimentally reducing FWBs positively affected implicit motor learning. We hypothesized that reducing FWBs would lead to both faster and stronger implicit learning, as measured using the alternating serial reaction time (ASRT) task. While we did show a manipulation effect on free will beliefs, there was no detectable effect on implicit learning processes. This finding adds to the growing body of evidence that free will belief manipulations do not meaningfully affect downstream behavior.

Spatial Attention in Serial Order Working Memory: An EEG Study.

Theoretical models explaining serial order processing link order information to specified position markers. However, the precise characteristics of position marking have remained largely elusive. Recent studies have shown that space is involved in marking serial position of items in verbal working memory (WM). Furthermore, it has been suggested, but not proven, that accessing these items involves horizontal shifts of spatial attention. We used continuous electroencephalography recordings to show that memory search in serial order verbal WM involves spatial attention processes that share the same electrophysiological signatures as those operating on the visuospatial WM and external space. Accessing an item from a sequence in verbal WM induced posterior "early directing attention negativity" and "anterior directing attention negativity" contralateral to the position of the item in mental space (i.e., begin items on the left; end items on the right). In the frequency domain, we observed posterior alpha suppression contralateral to the position of the item. Our results provide clear evidence for the involvement of spatial attention in retrieving serial information from verbal WM. Implications for WM models are discussed.

The impact of implicit and explicit suggestions that 'there is nothing to learn' on implicit sequence learning.

We can sometimes efficiently pick up statistical regularities in our environment in the absence of clear intentions or awareness, a process typically referred to as implicit sequence learning. In the current study, we tried to address the question whether suggesting participants that there is nothing to learn can impact this form of learning. If a priori predictions or intentions to learn are important in guiding implicit learning, we reasoned that suggesting participants that there is nothing to learn in a given context should hamper implicit learning. We introduced participants to random contexts that indicated that there was nothing to learn, either implicitly (i.e., by presenting blocks of random trials in "Experiment 1"), or explicitly (i.e., by explicitly instructing them in "Experiment 2"). Next, in a subsequent learning phase, participants performed an implicit sequence learning task. We found that these implicit or explicit suggestions that 'there was nothing to learn' did not influence the emergence of implicit knowledge in the subsequent learning phase. Although these findings seem consistent with simple associative or Hebbian learning accounts of implicit sequence learning (i.e., not steered by predictions), we discuss potential limitations that should inform future studies on the role of a priori predictions in implicit learning.

Does incidental sequence learning allow us to better manage upcoming conflicting events?

Recent proposals emphasize the role of learning in empirical markers of conflict adaptation. Some of these proposals are rooted in the assumption that contingency learning works not only on stimulus-response events but also on covert processes such as selective attention. In the present study, we explored how these learning processes may apply to trial-to-trial modulations of selective attention, mirroring the sequential nature of congruency sequence effects. Two groups of participants performed a four-choice Stroop task in which the color to which they responded on each trial acted as a probabilistic predictor either of the external response to be emitted on the next trial, or the congruency level (and therefore control demands) on the next trial. The results showed clear effects of sequence learning for external responses, but no evidence of learning about sequential stimulus-conflict associations. The implications of these results are discussed in relation to other learning-based phenomena of conflict adaptation and suggest that learning of stimulus-control associations is strongly constrained by event boundaries.

Dorsal anterior cingulate-brainstem ensemble as a reinforcement meta-learner.

Optimal decision-making is based on integrating information from several dimensions of decisional space (e.g., reward expectation, cost estimation, effort exertion). Despite considerable empirical and theoretical efforts, the computational and neural bases of such multidimensional integration have remained largely elusive. Here we propose that the current theoretical stalemate may be broken by considering the computational properties of a cortical-subcortical circuit involving the dorsal anterior cingulate cortex (dACC) and the brainstem neuromodulatory nuclei: ventral tegmental area (VTA) and locus coeruleus (LC). From this perspective, the dACC optimizes decisions about stimuli and actions, and using the same computational machinery, it also modulates cortical functions (meta-learning), via neuromodulatory control (VTA and LC). We implemented this theory in a novel neuro-computational model-the Reinforcement Meta Learner (RML). We outline how the RML captures critical empirical findings from an unprecedented range of theoretical domains, and parsimoniously integrates various previous proposals on dACC functioning.

Distinctiveness as a function of spatial expansion in verbal working memory: comment on Kreitz, Furley, Memmert, and Simons (2015).

In a recent study, Kreitz et al. (Psychological Research 79:1034-1041, 2015) reported on a relationship between verbal working memory capacity and visuo-spatial attentional breadth. The authors hinted at attentional control to be the major link underlying this relationship. We put forward an alternative explanation by framing it within the context of a recent theory on serial order in memory: verbal item sequences entering in working memory are coded by adding a spatial context that can be derived from reading/writing habits. The observation by Kreitz et al. (Psychological Research 79:1034-1041, 2015) enriches this framework by suggesting that a larger visuo-spatial attentional breadth allows for internal coding of the verbal items in a more (spatially) distinct manner-thereby increasing working memory performance. As such, Kreitz et al. (Psychological Research 79:1034-1041, 2015) is the first study revealing a functional link between visuo-spatial attentional breadth and verbal working memory size, which strengthens spatial accounts of serial order coding in working memory.

Reward anticipation modulates primary motor cortex excitability during task preparation.

Task preparation has been associated with a transient suppression of corticospinal excitability (CSE) before target onset, but it is an open question to what extent CSE suppression during task preparation is susceptible to motivational factors. Here, we examined whether CSE suppression is modulated by reward anticipation, and, if so, how this modulation develops over time. We administered a cue-target delay paradigm in which 1000ms before target onset a cue was presented indicating whether or not reward could be obtained for fast and accurate responses in a Simon task. Single-pulse transcranial magnetic stimulation was applied over left primary motor cortex (M1) during the delay period (400, 600, or 800ms after cue onset) or 200ms after target onset, and electromyography was obtained from the right first dorsal interosseous muscle. Behaviorally, the anticipation of reward improved performance (i.e. faster reaction times). Most importantly, during reward anticipation we observed a linear decrease of motor evoked potential amplitudes that was absent when no reward was anticipated. This suggests that reward anticipation modulates CSE during task preparation.

Conflict adaptation in schizophrenia: reviewing past and previewing future efforts.

INTRODUCTION: Cognitive control impairments have been suggested to be a critical component in the overall cognitive deficits observed in patients diagnosed with schizophrenia. Here, we zoom in on a specific function of cognitive control, conflict adaptation. Abnormal neural activity patterns have been observed for patients diagnosed with schizophrenia in core conflict adaptation areas such as anterior cingulate cortex and prefrontal cortex. On the one hand, this strongly indicates that conflict adaptation is affected. On the other hand, however, outcomes at the behavioural level are needed to create a window into a precise interpretation of this abnormal neural activity. METHODS: We present a narrative review of behavioural work within the context of conflict adaptation in schizophrenia, focusing on various major conflict adaptation markers: congruency sequence effects, proportion congruency effects, and post-error and post-conflict slowing. The review emphasises both methodological and theoretical aspects that are relevant to the understanding of conflict adaptation in schizophrenia. RESULTS: Based on the currently available set of behavioural studies on conflict adaptation, no clear-cut answer can be provided as to the precise conflict adaptation processes that are impaired (and to what extent) in schizophrenia populations. CONCLUSIONS: Future work is needed in state-of-the-art designs in order to reach better insight into the specifics of conflict adaptation impairments associated with schizophrenia.

Evidence for graded central processing resources in a sequential movement task.

In the present experiment, we examined slowing of the individual key presses of a familiar keying sequence by four different versions of a concurrent tone counting task. This was done to determine whether the same cognitive processor that has previously been assumed by the dual processor model (DPM) to initiate familiar keying sequences and assist in their execution, is involved also in the central processes of a very different task (viz. identifying tones and counting target tones). The present results confirm this hypothesis. They also suggest that in this particular situation the central processing resources underlying the cognitive processor can be distributed across the central processes of different tasks in a graded manner, rather than that they continue to behave like a single, central processor that serially switches between the central processes of the concurrently performed tasks. We argue that the production of highly practiced movement sequences can be considered automatic in the sense that execution of familiar movement sequences can continue without cognitive control once they have been initiated.

Spatial attention interacts with serial-order retrieval from verbal working memory.

The ability to maintain the serial order of events is recognized as a major function of working memory. Although general models of working memory postulate a close link between working memory and attention, such a link has so far not been proposed specifically for serial-order working memory. The present study provided the first empirical demonstration of a direct link between serial order in verbal working memory and spatial selective attention. We show that the retrieval of later items of a sequence stored in working memory-compared with that of earlier items-produces covert attentional shifts toward the right. This observation suggests the conceptually surprising notion that serial-order working memory, even for nonspatially defined verbal items, draws on spatial attention.

Sequential motor skill in preadolescent children: the development of automaticity.

This study investigated to what extent preadolescent children, like young adults, learn to perform sequential movements in an automatic fashion. A sample of 24 children (mean age = 11.3 years) practiced fixed 3-key and 6-key sequences in the discrete sequence production task by responding to key-specific stimuli via spatially compatible key presses. We compared their performance with that of 24 young adults (mean age = 22.0 years). Results showed that performance improved with practice for both age groups, although children were generally slower. Compared with young adults, children had less explicit knowledge but relied more on the available explicit knowledge when executing familiar 6-key sequences. Furthermore, they completed fewer of these sequences on the basis of just the first stimulus and showed a slower transition between successive segments within the sequences. Together, these findings provide insight into the degree to which preadolescent children develop automaticity in sequential motor skill, suggesting that preadolescent children automatize the processes underlying longer movement sequences slower and/or to a lesser extent than is the case with young adults. The current study is in line with the idea that there are several mechanisms that underlie sequencing skill and suggests that the use of these mechanisms may be dependent on age.

Testing the dopamine overdose hypothesis in action control: A study in people with Parkinson's disease.

Prior work on patients with Parkinson's disease (PD) has shown that the administration of dopaminergic medication in the early to intermediate stages of PD benefits (motor) functions associated with the dopamine-depleted dorsal striatal circuitry but may 'overdose' and interfere with (cognitive) functions associated with the relatively intact ventral striatal circuitry. The present study aimed to elucidate this so-called dopamine overdose hypothesis for the action control domain. Using a within-subject design in a sample of 13 people with PD, we evaluated the effect of dopaminergic medication on two cognitive processes underlying goal-directed behaviour, namely action selection and initiation through event binding and conflict adaptation. We also investigated whether individual differences in the magnitude of medication effects were associated across these processes. Results showed no indications that dopaminergic medication affects action selection and initiation or conflict adaptation in PD patients. Additionally, we observed no correlations between both cognitive processes nor between individual differences in medication effects. Our findings do not support the notion that dopaminergic medication modulates action control processes, suggesting that the dopamine overdose hypothesis may only apply to a specific set of cognitive processes and should potentially be refined.

Context-dependent motor skill: perceptual processing in memory-based sequence production.

Previous studies have shown that motor sequencing skill can benefit from the reinstatement of the learning context-even with respect to features that are formally not required for appropriate task performance. The present study explored whether such context-dependence develops when sequence execution is fully memory-based-and thus no longer assisted by stimulus-response translations. Specifically, we aimed to distinguish between preparation and execution processes. Participants performed two keying sequences in a go/no-go version of the discrete sequence production task in which the context consisted of the color in which the target keys of a particular sequence were displayed. In a subsequent test phase, these colors either were the same as during practice, were reversed for the two sequences or were novel. Results showed that, irrespective of the amount of practice, performance across all key presses in the reversed context condition was impaired relative to performance in the same and novel contexts. This suggests that the online preparation and/or execution of single key presses of the sequence is context-dependent. We propose that a cognitive processor is responsible both for these online processes and for advance sequence preparation and that combined findings from the current and previous studies build toward the notion that the cognitive processor is highly sensitive to changes in context across the various roles that it performs.

Context-dependent motor skill and the role of practice.

Research has shown that retrieval of learned information is better when the original learning context is reinstated during testing than when this context is changed. Recently, such contextual dependencies have also been found for perceptual-motor behavior. The current study investigated the nature of context-dependent learning in the discrete sequence production task, and in addition examined whether the amount of practice affects the extent to which sequences are sensitive to contextual alterations. It was found that changing contextual cues-but not the removal of such cues-had a detrimental effect on performance. Moreover, this effect was observed only after limited practice, but not after extensive practice. Our findings support the notion of a novel type of context-dependent learning during initial motor skill acquisition and demonstrate that this context-dependence reduces with practice. It is proposed that a gradual development with practice from stimulus-driven to representation-driven sequence execution underlies this practice effect.

Tenacious instructions: How to dismantle newly instructed task rules?

Humans excel in instruction following to boost performance in unfamiliar situations. We can do so through so-called prepared reflexes: Abstract instructions are instantly translated into appropriate task rules in procedural working memory, after which imperative stimuli directly trigger their corresponding responses in a ballistic, reflex-like manner. But how much control do we have over these instructed task rules when their reflexes suddenly lose their relevance? Inspired by the phenomenon of directed forgetting in declarative working memory, we here tested across four experiments whether the presentation of (implicit or explicit) task cancellation cues results in the directed dismantling of recently instructed task rules. Our findings suggest that-even when cancelation cues are actively processed-such dismantling does not occur (Experiment 1-3) unless the no-longer relevant task rules are replaced by a new set of rules (Experiment 4). These findings and their implications are discussed in the broader context of action control and working memory. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Motor skill learning in the middle-aged: limited development of motor chunks and explicit sequence knowledge.

The present study examined whether middle-aged participants, like young adults, learn movement patterns by preparing and executing integrated sequence representations (i.e., motor chunks) that eliminate the need for external guidance of individual movements. Twenty-four middle-aged participants (aged 55-62) practiced two fixed key press sequences, one including three and one including six key presses in the discrete sequence production task. Their performance was compared with that of 24 young adults (aged 18-28). In the middle-aged participants motor chunks as well as explicit sequence knowledge appeared to be less developed than in the young adults. This held especially with respect to the unstructured 6-key sequences in which most middle-aged did not develop independence of the key-specific stimuli and learning seems to have been based on associative learning. These results are in line with the notion that sequence learning involves several mechanisms and that aging affects the relative contribution of these mechanisms.

It is harder than you think: On the boundary conditions of exploiting congruency cues.

Humans are able to anticipate abstract task demands and prepare attentional sets accordingly. A popular method to study this ability is to include explicit cues that signal the required level of cognitive control in conflict tasks (e.g., whether or not word meaning will correspond to the task-relevant font color in a Stroop task). Here, we demonstrate that this ability is more limited than assumed by most theories. Starting from a recent finding that implicit cues on the previous trial do not aid task performance, we demonstrate that these cues remain inefficient even when participants are explicitly instructed about their meaning, when the cue-stimulus interval is prolonged, or when the cues are deterministic and blocked (Experiments 1-4). In fact, the cues sometimes even impaired performance. Extending cue-information into the intertrial interval did not help (Experiment 5), and even though we replicated previous cueing effects using explicit cues in between trials in the vocal Stroop task (Experiment 7), this effect disappeared when using manual responses or presenting the cue in the preceding trial (Experiments 6, 8, and 9), and only benefited congruent responses when the intertrial interval was reduced (Experiment 10). Together, these findings point to important boundary conditions in cued control: The ability to prepare for control demands on a trial-by-trial basis is restricted to situations in which cues are presented alone, and where the task involves a nonarbitrary stimulus-response mapping. We discuss these findings in light of recent theories that emphasize the role of event boundaries and the value of cognitive control. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Does a 7-day restriction on the use of social media improve cognitive functioning and emotional well-being? Results from a randomized controlled trial.

INTRODUCTION: Screen time apps that allow smartphone users to manage their screen time are assumed to combat negative effects of smartphone use. This study explores whether a social media restriction, implemented via screen time apps, has a positive effect on emotional well-being and sustained attention performance. METHODS: A randomized controlled trial (N = 76) was performed, exploring whether a week-long 50% reduction in time spent on mobile Facebook, Instagram, Snapchat and YouTube is beneficial to attentional performance and well-being as compared to a 10% reduction. RESULTS: Unexpectedly, several participants in the control group pro-actively reduced their screen time significantly beyond the intended 10%, dismantling our intended screen time manipulation. Hence, we analyzed both the effect of the original manipulation (i.e. treatment-as-intended), and the effect of participants' relative reduction in screen time irrespective of their condition (i.e. treatment-as-is). Neither analyses revealed an effect on the outcome measures. We also found no support for a moderating role of self-control, impulsivity or Fear of Missing Out. Interestingly, across all participants behavioral performance on sustained attention tasks remained stable over time, while perceived attentional performance improved. Participants also self-reported a decrease in negative emotions, but no increase in positive emotions. CONCLUSION: We discuss the implications of our findings in light of recent debates about the impact of screen time and formulate suggestions for future research based on important limitations of the current study, revolving among others around appropriate control groups as well as the combined use of both subjective and objective (i.e., behavioral) measures.

Do preliterate children spontaneously employ spatial coding for serial order in working memory?

The ability to memorize arbitrary sequences contributes to cognitive faculties like language and mathematics. Research suggests that in literate adults, serial order in verbal working memory (WM) is grounded in spatial attention and is mentally organized according to our reading habits, that is, from left-to-right in Western cultures. Currently, it is unknown whether spatialization is a consequence of literacy, or whether the ability already exists early in life but is shaped by literacy in "calibrating" the initial individual differences in the orientation of spatial coding. Here, we investigated the spatial coding of serial order in WM in 5-year-old children who did not yet enter formal literacy education. At the group level, no systematic spatial coding was observed. To investigate whether this absence was due to subjects with reliable but opposing effects, we determined the prevalence of spatial coding at the individual level. This analysis revealed that 36% of the children systematically associated serial order to space, with approximately half of them coding from left-to-right and the rest from right-to-left. These results indicate that a subgroup of preliterate children associate serial order with space and suggest that reading and writing experience calibrates the orientation of spatial coding with reading habits.