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Baseline and task‐evoked pupil measures are known to reflect the activity of the nervous system's central arousal mechanisms. With the increasing availability, affordability and flexibility of video‐based eye tracking hardware, these measures may one day find practical application in real‐time biobehavioural monitoring systems to assess performance or fitness for duty in tasks requiring vigilant attention. But real‐world vigilance tasks are predominantly visual in their nature and most research in this area has taken place in the auditory domain. Here, we explore the relationship between pupil size—both baseline and task‐evoked—and behavioural performance measures in two novel vigilance tasks requiring visual target detection: (1) a traditional vigilance task involving prolonged, continuous and uninterrupted performance (n = 28) and (2) a psychomotor vigilance task (n = 25). In both tasks, behavioural performance and task‐evoked pupil responses declined as time spent on task increased, corroborating previous reports in the literature of a vigilance decrement with a corresponding reduction in task‐evoked pupil measures. Also in line with previous findings, baseline pupil size did not show a consistent relationship with performance measures. Our data offer novel insights into the complex interplay of brain systems involved in vigilant attention and question the validity of the assumption that baseline (prestimulus) pupil size and task‐evoked (poststimulus) pupil measures reflect the tonic and phasic firing modes of the locus coeruleus. [ABSTRACT FROM AUTHOR]

Anterograde interference emerges when two opposite (B → A) or identical tasks (A → A) are learned in close temporal succession, suggesting that interference cannot be fully accounted for by competing memories. Informed by neurobiological evidence, this work tested the hypothesis that interference depends upon the degree of overlap between the neural networks involved in the learning of two tasks. In a fully within‐subject and counterbalanced design, participants (n = 24) took part in two learning sessions where the putative overlap between learning‐specific neural networks was behaviourally manipulated across four conditions by modifying reach direction and the effector used during gradual visuomotor adaptation. The results showed that anterograde interference emerged regardless of memory competition—that is, to a similar extent in the B → A and A → A conditions—and along a gradient as a function of the tasks' similarity. Specifically, learning under similar reaching conditions generated more anterograde interference than learning under dissimilar reaching conditions, suggesting that putatively overlapping neural networks are required to generate interference. Overall, these results indicate that competing memories are not the sole contributor to anterograde interference and suggest that overlapping neural networks between two learning sessions are required to trigger interference. One discussed possibility is that initial learning modifies the properties of its neural networks to constrain further plasticity induction and learning capabilities, therefore causing anterograde interference in a network‐dependent manner. One implication is that learning‐specific neural networks must be maximally dissociated to minimize the interfering influences of previous learning on subsequent learning. [ABSTRACT FROM AUTHOR]

Working memory is a subcategory of short‐term memory that voluntarily maintains behaviourally relevant information to prepare for a subsequent action. An established theory is that working memory is supported by the prefrontal cortex (PFC) for executive control, while the hippocampus (HPC) is largely involved in long‐term episodic memory. Recent studies suggest that the HPC is also involved in perception and short‐term storage. However, it remains unclear whether the HPC supports active maintenance of short‐term memory as working memory. To address this question, we devised a new delayed matching‐to‐sample task in which two visual items were presented at different locations one by one as samples. The sequential presentations of sample stimuli allowed us to dissociate the contents of working memory (i.e., identities and locations of two samples) from the constituent perceived information of single samples. By applying representational similarity analysis (RSA) to the blood‐oxygen‐level‐dependent (BOLD) signals of human participants, we investigated the delay activity after the two sample presentations. The results of the RSA showed that the right HPC signalled only the second sample as a conjunctional representation of its item identity and location. In contrast, the right PFC, including both lateral and medial parts, represented the conjunctional information of both samples. These results suggested that the HPC may support short‐term memory for retrospective coding to retain information of the last event rather than for prospective coding coupled with working memory. [ABSTRACT FROM AUTHOR]

Laboratory electroencephalography (EEG) studies have already provided important insights into the neuronal mechanisms of performance monitoring. However, to our knowledge no study so far has examined neuronal correlates of performance monitoring using an ecologically valid task outside a typical laboratory setting. Therefore, we examined midfrontal theta and the feedback‐related negativity (FRN) using mobile EEG in a physical shooting task within an ecologically valid environment with highly dynamical visual feedback. Participants shot a target using a toy gun while moving and looking around freely. Shots that missed the target evoked stronger midfrontal theta activity than hits and this response was rather phase‐unlocked. There was no difference between misses and hits in the FRN. The results raise the question whether the absence of certain ERP components like the FRN could be due to methodological reasons or to the fact that partially different neuronal processes may be activated in the laboratory as compared to more ecologically valid tasks. Overall, our results indicate that crucial neurocognitive processes of performance monitoring can be assessed in highly dynamic and ecologically valid settings by mobile EEG. [ABSTRACT FROM AUTHOR]

Task‐based functional magnetic resonance imaging (MRI) neuroimaging for the study of cognitive neuroscience provides insight into how the brain responds to increasing cognitive demands. Theoretical models of neural–cognitive relationships define neural efficiency and neural capacity as two parameters to describe the rate of gain of brain activity and the upper limits of the increases, respectively. Although qualitatively well described, there are limited discussions and demonstrations of estimating these parameters from data. The current work presents a method using a quadratic equation model of cognitive demands. The methods were applied to 21 healthy young adults while engaging in four levels of the verbal n‐back working memory task (0, 1, 2 and 3‐back). Measures of the area under the curve captured both linear and curvilinear responses to quantify the locations and amounts of task‐related increases in brain activity. In addition, we calculated voxel‐wise maps of neural efficiency and neural capacity. Results showed increases in brain activation in regions typically involved in working memory. The relationships between increasing cognitive demands and brain activity also differed across the brain within and between individuals, as indicated by differential neural efficiency and neural capacity values. This approach provides tools for evaluating current theories about the relationships between brain activity and cognition. Neural efficiency and neural capacity provide physiological measures of brain activity, which will help evaluate how age, disease and intervention processes affect brain activity. Finally, all presented methods are readily applicable using standard current software packages for neuroimaging. [ABSTRACT FROM AUTHOR]

Finger tapping is a task widely used in a variety of experimental paradigms, in particular to understand sensorimotor synchronization and time processing in the range of hundreds of milliseconds (millisecond timing). Normally, subjects do not receive any instruction about what to attend to and the results are seldom interpreted taking into account the possible effects of attention. In this work we show that attention can be oriented to the purely temporal aspects of a paced finger‐tapping task and that it affects performance. Specifically, time‐oriented attention improves the accuracy in paced finger tapping and it also increases the resynchronization efficiency after a period perturbation. We use two markers of the attention level: auditory ERPs and subjective report of the mental workload. In addition, we propose a novel algorithm to separate the auditory, stimulus‐related components from the somatosensory, response‐related ones, which are naturally overlapped in the recorded EEG. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We focused on how the rat uses olfactory cues in a single‐pellet reaching task, which is composed of three successive learned responses, Orient, Transport, and Withdrawal. Orient comprised: front wall detection, slot localisation, and nose poke until reach start. High‐speed video‐recording enabled us to describe the temporal features of this sequence in controls vs. 3–5 and 12–14 days after bilateral bulbectomy in trials with (P trial) vs. without (no‐P trial) pellet. In controls, the full sequence was complete in P trials, while it was interrupted after Orient in no P‐trials. After bulbectomy, the full sequence was seen in both P and no‐P trials at days 3–5 and 12–14 and there was an increase in Orient duration due to the increased time in slot/shelf localisation. Unlike in controls, in anosmic rats, the first nose contact with the front wall took place below the slot/shelf level, and the number of nose touches together with the number of whisker cycles was significantly higher at 3–5 but not at 12–14 days. The relationship between nose touches and whisker cycles was linear in all experimental conditions. Bulbectomy resulted in no changes in the Transport duration or the time the paw spent out of the slot. These findings suggest that olfaction allows the animal to orient itself in pellet localisation, and offers insight into the contribution of olfaction during different stages of natural behaviour in skilled reaching task. [ABSTRACT FROM AUTHOR]

Semantic reversal anomalies (SRAs)—sentences where an implausibility is created by reversing participant roles—have attracted much attention in the literature on the electrophysiology of language. In spite of being syntactically well formed but semantically implausible, these sentences unexpectedly elicited a monophasic P600 effect in English and Dutch rather than an N400 effect. Subsequent research revealed variability in the presence/absence of an N400 effect to SRAs depending on the language examined and the choice of verb type in English. However, most previous studies employed the same presentation modality (visual) and task (acceptability judgement). Here, we conducted two experiments and three statistical analyses to investigate the influence of stimulus modality, task demand and statistical choices on event‐related potential (ERP) response patterns to SRAs in English. We reproduced a previous study's procedure and analysis (N. Bourguignon et al. (2012) Brain and Language, 122, 179–189) and further introduced between‐subjects factors of task type and modality, using mixed‐effects modelling to analyse the data. We observed an N400 effect to typical English SRAs (agent subject verbs, e.g. "the fries will eat the boys"), which contrasts existing literature and was not predicted by existing theories that account for SRA processing. Task demand modulated the ERPs elicited by SRAs, while auditory presentation led to increased comprehension accuracy and a more broadly distributed ERP. Finally, the statistical methods used influenced the presence/absence of ERP effects. Our results suggest a sensitivity of language‐related ERP patterns to methodological parameters, and we conclude that future experiments should take this into careful consideration. [ABSTRACT FROM AUTHOR]

We combined fMRI with eye tracking and speech recording to examine the neural and cognitive mechanisms that underlie reading. To simplify the study of the complex processes involved during reading, we used naming speed (NS) tasks (also known as rapid automatized naming or RAN) as a focus for this study, in which average reading right‐handed adults named sets of stimuli (letters or objects) as quickly and accurately as possible. Due to the possibility of spoken output during fMRI studies creating motion artifacts, we employed both an overt session and a covert session. When comparing the two sessions, there were no significant differences in behavioral performance, sensorimotor activation (except for regions involved in the motor aspects of speech production) or activation in regions within the left‐hemisphere‐dominant neural reading network. This established that differences found between the tasks within the reading network were not attributed to speech production motion artifacts or sensorimotor processes. Both behavioral and neuroimaging measures showed that letter naming was a more automatic and efficient task than object naming. Furthermore, specific manipulations to the NS tasks to make the stimuli more visually and/or phonologically similar differentially activated the reading network in the left hemisphere associated with phonological, orthographic and orthographic‐to‐phonological processing, but not articulatory/motor processing related to speech production. These findings further our understanding of the underlying neural processes that support reading by examining how activation within the reading network differs with both task performance and task characteristics. [ABSTRACT FROM AUTHOR]

Effective decision‐making depends on an animal's ability to predict and select the outcome of greatest value, and the nucleus accumbens (NAc) and its dopaminergic input play a key role in this process. We previously reported that rapid dopamine release in the NAc shell preferentially tracks the "preferred" (i.e., large reward) option during cues that predict the ability to respond for rewards of different sizes, as well as during reward delivery itself. The present study assessed whether shell dopamine release at these discrete times selectively mediated choice behavior for rewards of different magnitudes using optogenetics. Here, using Long Evans TH:Cre± rats we employed selective optogenetic stimulation of dopamine terminals in the NAc shell during either reward‐predictive cues (experiment 1) or reward delivery (experiment 2) in a magnitude‐based decision‐making task. We found that in TH:Cre± rats, but not littermate controls, optical stimulation during low‐magnitude reward delivery during forced choice trials was sufficient to bias preference for this option when given a choice. In contrast, optical stimulation of shell dopamine terminals during low‐magnitude reward‐predictive cues in forced choice trials did not shift free choice behavior in TH:Cre± rats or controls. The findings indicate that preferential dopamine signaling in the NAc shell during reward outcome (delivery), but not reward‐predictive cues are sufficient to influence choice behavior in our task supporting a causal role of dopamine in the NAc shell in reward outcome value, but not value‐based predictive strategies. [ABSTRACT FROM AUTHOR]

An integral aspect of human cognition is the ability to inhibit stimulus‐driven, habitual responses, in favour of complex, voluntary actions. In addition, humans can also alternate between different tasks. This comes at the cost of degraded performance when compared to repeating the same task, a phenomenon called the "task‐switch cost." While task switching and inhibitory control have been studied extensively, the interaction between them has received relatively little attention. Here, we used the SERIA model, a computational model of antisaccade behaviour, to draw a bridge between them. We investigated task switching in two versions of the mixed antisaccade task, in which participants are cued to saccade either in the same or in the opposite direction to a peripheral stimulus. SERIA revealed that stopping a habitual action leads to increased inhibitory control that persists onto the next trial, independently of the upcoming trial type. Moreover, switching between tasks induces slower and less accurate voluntary responses compared to repeat trials. However, this only occurs when participants lack the time to prepare the correct response. Altogether, SERIA demonstrates that there is a reconfiguration cost associated with switching between voluntary actions. In addition, the enhanced inhibition that follows antisaccade but not prosaccade trials explains asymmetric switch costs. In conclusion, SERIA offers a novel model of task switching that unifies previous theoretical accounts by distinguishing between inhibitory control and voluntary action generation and could help explain similar phenomena in paradigms beyond the antisaccade task. [ABSTRACT FROM AUTHOR]