The Role of Dopamine in Value-Based Attentional Orienting

Prospective Distractor Information Reduces Reward-Related Attentional Capture

Motivationally salient stimuli, such as those associated with reward, can automatically gain attentional prioritisation - even when individuals are motivated to ignore such stimuli. This 'attentional bias for reward' has often been interpreted as evidence for involuntary Pavlovian 'sign tracking' behaviour. The prioritisation of reward-signalling distractors may additionally reflect a drive to gain information about the state of the world, irrespective of the particular reward that is being signalled. In the current study we assessed whether forewarning participants on each trial as to the upcoming features of a distractor would reduce reward-related attentional capture. This manipulation reduces the information provided by the distractor, without affecting the magnitude of the signalled reward. Using eye tracking in Experiment 1, we found that reward-related attentional capture was virtually eliminated when participants were informed of the upcoming distractor colour (relative to the baseline condition when no information was provided). In Experiment 2, using a response-time version of the task, we again found a significant reduction in reward-related attentional capture when participants received information about the colour of an upcoming distractor, or information about the value of the upcoming reward. Finally, in Experiment 3 we assessed whether participants were using the pre-trial information to strategically inhibit attention to the upcoming distractor colour. The results of these experiments are discussed within the context of information-seeking accounts of reward-related attentional capture effects.

Manipulating the reliability of target-color information modulates value-driven attentional capture

Previously rewarded stimuli slow response times (RTs) during visual search, despite being physically non-salient and no longer task-relevant or rewarding. Such value-driven attentional capture (VDAC) has been measured in a training-test paradigm. In the training phase, the search target is rendered in one of two colors (one predicting high reward and the other low reward). In this study, we modified this traditional training phase to include pre-cues that signaled reliable or unreliable information about the trial-to-trial color of the training phase search target. Reliable pre-cues indicated the upcoming target color with certainty, whereas unreliable pre-cues indicated the target was equally likely to be one of two distinct colors. Thus reliable and unreliable pre-cues provided certain and uncertain information, respectively, about the magnitude of the upcoming reward. We then tested for VDAC in a traditional test phase. We found that unreliably pre-cued distractors slowed RTs and drew more initial eye movements during search for the test-phase target, relative to reliably pre-cued distractors, thus providing novel evidence for an influence of information reliability on attentional capture. That said, our experimental manipulation also eliminated value-dependency (i.e., slowed RTs when a high-reward-predicting distractor was present relative to a low-reward-predicting distractor) for both kinds of distractors. Taken together, these results suggest that target-color uncertainty, rather than reward magnitude, played a critical role in modulating the allocation of value-driven attention in this study.

From learned value to sustained bias: how reward conditioning changes attentional priority

Introduction

Attentional bias to reward-associated stimuli can occur even when it interferes with goal-driven behavior. One theory posits that dopaminergic signaling in the striatum during reward conditioning leads to changes in visual cortical and parietal representations of the stimulus used, and this, in turn, sustains attentional bias even when reward is discontinued. However, only a few studies have examined neural activity during both rewarded and unrewarded task phases.

Methods

In the current study, participants first completed a reward-conditioning phase, during which responses to certain stimuli were associated with monetary reward. These stimuli were then included as non-predictive cues in a spatial cueing task. Participants underwent functional brain imaging during both task phases.

Results

The results show that striatal activity during the learning phase predicted increased visual cortical and parietal activity and decreased ventro-medial prefrontal cortex activity in response to conditioned stimuli during the test. Striatal activity was also associated with anterior cingulate cortex activation when the reward-conditioned stimulus directed attention away from the target.

Discussion

Our findings suggest that striatal activity during reward conditioning predicts the degree to which reward history biases attention through learning-induced changes in visual and parietal activities.

Trichotomy revisited: A monolithic theory of attentional control

The control of attention was long held to reflect the influence of two competing mechanisms of assigning priority, one goal-directed and the other stimulus-driven. Learning-dependent influences on the control of attention that could not be attributed to either of those two established mechanisms of control gave rise to the concept of selection history and a corresponding third mechanism of attentional control. The trichotomy framework that ensued has come to dominate theories of attentional control over the past decade, replacing the historical dichotomy. In this theoretical review, I readily affirm that distinctions between the influence of goals, salience, and selection history are substantive and meaningful, and that abandoning the dichotomy between goal-directed and stimulus-driven mechanisms of control was appropriate. I do, however, question whether a theoretical trichotomy is the right answer to the problem posed by selection history. If we reframe the influence of goals and selection history as different flavors of memory-dependent modulations of attentional priority and if we characterize the influence of salience as a consequence of insufficient competition from such memory-dependent sources of priority, it is possible to account for a wide range of attention-related phenomena with only one mechanism of control. The monolithic framework for the control of attention that I propose offers several concrete advantages over a trichotomy framework, which I explore here.

Temperament and probabilistic predictive coding in visual-spatial attention

Cholinergic (Ach), Noradrenergic (NE), and Dopaminergic (DA) pathways play an important role in the regulation of spatial attention. The same neurotransmitters are also responsible for inter-individual differences in temperamental traits. Here we explored whether biologically defined temperamental traits determine differences in the ability to orient spatial attention as a function of the probabilistic association between cues and targets. To this aim, we administered the Structure of Temperament Questionnaire (STQ-77) to a sample of 151 participants who also performed a Posner task with central endogenous predictive (80 % valid/20 % invalid) or non-predictive cues (50 % valid/50 % invalid). We found that only participants with high scores in Plasticity and Intellectual Endurance showed a selective abatement of attentional costs with non-predictive cues. In addition, stepwise regression showed that costs in the non-predictive condition were negatively predicted by scores in Plasticity and positively predicted by scores in Probabilistic Thinking. These results show that stable temperamental characteristics play an important role in defining the inter-individual differences in attentional behaviour, especially in the presence of different probabilistic organisations of the sensory environment. These findings emphasize the importance of considering temperamental and personality traits in social and professional environments where the ability to control one's attention is a crucial functional skill.

Loss aversion in the control of attention

Loss aversion is a psychological bias where an increase in loss is perceived as being larger than an equivalent increase in gain. In the present study, two experiments were conducted to explore whether attentional control reflects loss aversion. Participants performed a visual search task. On each trial, a red target and a green target were presented simultaneously, and participants were free to search for either one. Participants always gained points when they searched for a gain color target (e.g., red). However, they gained or lost points when they searched for a gain-loss color target (e.g., green). In Experiment 1, the expected values of the gain color and the gain-loss color were equal. Therefore, for maximizing the reward, participants did not need to preferably search for a particular color. However, results showed that participants searched for the gain color target more than the gain-loss color target, suggesting stronger attentional control for the gain color than the gain-loss color. In Experiment 2, even though the expected value of the gain-loss color was greater than that of the gain color, attention was allocated to the gain color more than to the gain-loss color. The results imply that attentional control can operate in accordance with the loss aversion principle when the boundary conditions for loss aversion in a repeated binary decision-making task were met.

Reward history modulates visual attention in an avian model

Attention can be biased towards previously reward-associated stimuli even when they are task-irrelevant and physically non-salient, although studies of reward-modulated attention have been largely limited to primate (including human and nonhuman) models. Birds have been shown to have the capacity to discriminate reward and spatial cues in a manner similar to primates, but whether reward history involuntarily affects their attention in the same way remains unclear. We adapted a spatial cueing paradigm with differential rewards to investigate how reward modulates the allocation of attention in peafowl (Pavo cristatus). The birds were required to locate and peck a target on a computer screen that was preceded by a high-value or low-value color cue that was uninformative with respect to the location of the upcoming target. All birds exhibited a validity effect (performance enhanced on valid compared to invalid cue), and an interaction effect between value and validity was evident at the group level, being particularly pronounced in the birds with the greatest amount of reward training. The time course of reward learning was conspicuously incremental, phenomenologically slower compared to primates. Our findings suggest a similar influence of reward history on attention across phylogeny despite a significant difference in neuroanatomy.

Neural correlates of value-driven spatial orienting

Reward learning has been shown to habitually guide overt spatial attention to specific regions of a scene. However, the neural mechanisms that support this bias are unknown. In the present study, participants learned to orient themselves to a particular quadrant of a scene (a high-value quadrant) to maximize monetary gains. This learning was scene-specific, with the high-value quadrant varying across different scenes. During a subsequent test phase, participants were faster at identifying a target if it appeared in the high-value quadrant (valid), and initial saccades were more likely to be made to the high-value quadrant. fMRI analyses during the test phase revealed learning-dependent priority signals in the caudate tail, superior colliculus, frontal eye field, anterior cingulate cortex, and insula, paralleling findings concerning feature-based, value-driven attention. In addition, ventral regions typically associated with scene selection and spatial information processing, including the hippocampus, parahippocampal gyrus, and temporo-occipital cortex, were also implicated. Taken together, our findings offer new insights into the neural architecture subserving value-driven attention, both extending our understanding of nodes in the attention network previously implicated in feature-based, value-driven attention and identifying a ventral network of brain regions implicated in reward's influence on scene-dependent spatial orienting.

Dead rats, dopamine, performance metrics, and peacock tails: Proxy failure is an inherent risk in goal-oriented systems

When a measure becomes a target, it ceases to be a good measure. For example, when standardized test scores in education become targets, teachers may start "teaching to the test," leading to breakdown of the relationship between the measure - test performance - and the underlying goal - quality education. Similar phenomena have been named and described across a broad range of contexts, such as economics, academia, machine learning, and ecology. Yet it remains unclear whether these phenomena bear only superficial similarities, or if they derive from some fundamental unifying mechanism. Here, we propose such a unifying mechanism, which we label proxy failure. We first review illustrative examples and their labels, such as the "cobra effect," "Goodhart's law," and "Campbell's law." Second, we identify central prerequisites and constraints of proxy failure, noting that it is often only a partial failure or divergence. We argue that whenever incentivization or selection is based on an imperfect proxy measure of the underlying goal, a pressure arises that tends to make the proxy a worse approximation of the goal. Third, we develop this perspective for three concrete contexts, namely neuroscience, economics, and ecology, highlighting similarities and differences. Fourth, we outline consequences of proxy failure, suggesting it is key to understanding the structure and evolution of goal-oriented systems. Our account draws on a broad range of disciplines, but we can only scratch the surface within each. We thus hope the present account elicits a collaborative enterprise, entailing both critical discussion as well as extensions in contexts we have missed.

Value-based decision-making network functional connectivity correlates with substance use and delay discounting behaviour among young adults

Substance use disorders are characterized by reduced control over the quantity and frequency of psychoactive substance use and impairments in social and occupational functioning. They are associated with poor treatment compliance and high rates of relapse. Identification of neural susceptibility biomarkers that index risk for developing a substance use disorder can facilitate earlier identification and treatment. Here, we aimed to identify the neurobiological correlates of substance use frequency and severity amongst a sample of 1,200 (652 females) participants aged 22-37 years from the Human Connectome Project. Substance use behaviour across eight classes (alcohol, tobacco, marijuana, sedatives, hallucinogens, cocaine, stimulants, opiates) was measured using the Semi-Structured Assessment for the Genetics of Alcoholism. We explored the latent organization of substance use behaviour using a combination of exploratory structural equation modelling, latent class analysis, and factor mixture modelling to reveal a unidimensional continuum of substance use behaviour. Participants could be rank ordered along a unitary severity spectrum encompassing frequency of use of all eight substance classes, with factor score estimates generated to represent each participant's substance use severity. Factor score estimates and delay discounting scores were compared with functional connectivity in 650 participants with imaging data using the Network-based Statistic. This neuroimaging cohort excludes participants aged 31 and over. We identified brain regions and connections correlated with impulsive decision-making and poly-substance use, with the medial orbitofrontal, lateral prefrontal and posterior parietal cortices emerging as key hubs. Functional connectivity of these networks could serve as susceptibility biomarkers for substance use disorders, informing earlier identification and treatment.

Automatic and controlled attentional orienting toward emotional faces in patients with Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative motor disorder that can associate with deficits in cognitive and emotional processing. In particular, PD has been reported to be mainly associated with defects in executive control and orienting attentional systems. The deficit in emotional processing mainly emerged in facial expression recognition. It is possible that the defects in emotional processing in PD may be secondary to other cognitive impairments, such as attentional deficits. This study was designed to systematically investigate the different weight of automatic and controlled attentional orienting mechanisms implied in emotional selective attention in PD. To address our purpose, we assessed drug-naïve PD patients and age-matched healthy controls with two dot-probe tasks that differed for stimuli duration. Automatic and controlled attentions were evaluated with stimuli lasting 100 ms and 500 ms, respectively. Furthermore, we introduced an emotion recognition task to investigate the performance in explicit emotion classification. The stimuli used in both the tasks dot-probe and emotion recognition were expressive faces displaying neutral, disgusted, fearful, and happy expressions.Our results showed that in PD patients, compared with healthy controls, there was 1) an alteration of automatic and controlled attentional orienting toward emotional faces in both the dot-probe tasks (with short and long durations), and 2) no difference in the emotion recognition task. These findings suggest that, from the early stages of the disease, PD can yield specific deficits in implicit emotion processing task (i.e., dot-probe task) despite a normal performance in explicit tasks that demand overt emotion recognition.

On the Relationship between Value- and Threat-Driven Attentional Capture and Approach-Avoidance Biases

Reward learning and aversive conditioning have consequences for attentional selection, such that stimuli that come to signal reward and threat bias attention regardless of their valence. Appetitive and aversive stimuli have distinctive influences on response selection, such that they activate an approach and an avoidance response, respectively. However, whether the involuntary influence of reward- and threat-history-laden stimuli extends to the manner in which a response is directed remains unclear. Using a feedback-joystick task and a manikin task, which are common paradigms for examining valence-action bias, we demonstrate that reward- and threat-signalling stimuli do not modulate response selection. Stimuli that came to signal reward and threat via training biased attention and invigorated action in general, but they did not facilitate an approach and avoidance response, respectively. We conclude that attention can be biased towards a stimulus as a function of its prior association with reward or aversive outcomes without necessarily influencing approach vs. avoidance tendencies, such that the mechanisms underlying the involuntary control of attention and behaviour evoked by valent stimuli can be decoupled.

The persistence of value-driven attention capture is task-dependent

Visual features previously associated with reward can capture attention even when task-irrelevant, a phenomenon known as value-driven attention capture (VDAC). VDAC persists without reinforcement, unlike other forms of learning, where removing reinforcement typically leads to extinction. In five experiments, factors common to many studies were manipulated to examine their impact on VDAC and its extinction. All experiments included learning and test phases. During learning, participants completed a visual search task during which one of two target colors was associated with a reward, and the other with no reward. During test, 1 week later, participants completed another visual search task in which the reward association was not reinforced. When a rewarded feature remained task-relevant (Experiment 1), VDAC was observed. When the rewarded feature was made task-irrelevant (Experiments 2-5) there was no evidence of a VDAC effect, except when the target feature was physically salient and there was a reduction in the frequency of exposure to the reward-associated feature (Experiment 5). We failed to find evidence of VDAC in Experiments 2-4, suggesting that VDAC may depend on the demands of the task resulting in vulnerability to VDAC. When VDAC was observed, extinction was also observed. This indicates that VDAC is subject to extinction as would be expected from an effect driven by reinforcement learning.

Sign-tracking modulates reward-related neural activation to reward cues, but not reward feedback

Research shows cognitive and neurobiological overlap between sign-tracking [value-modulated attentional capture (VMAC) by response-irrelevant, discrete cues] and maladaptive behaviour (e.g. substance abuse). We investigated the neural correlates of sign-tracking in 20 adults using an additional singleton task (AST) and functional magnetic resonance imaging (fMRI). Participants responded to a target to win monetary reward, the amount of which was signalled by singleton type (reward cue: high value vs. low value). Singleton responses resulted in monetary deductions. Sign-tracking-greater distraction by high-value vs. low-value singletons (H > L)-was observed, with high-value singletons producing slower responses to the target than low-value singletons. Controlling for age and sex, analyses revealed no differential brain activity across H > L singletons. Including sign-tracking as a regressor of interest revealed increased activity (H > L singletons) in cortico-subcortical loops, regions associated with Pavlovian conditioning, reward processing, attention shifts and relative value coding. Further analyses investigated responses to reward feedback (H > L). Controlling for age and sex, increased activity (H > L reward feedback) was found in regions associated with reward anticipation, attentional control, success monitoring and emotion regulation. Including sign-tracking as a regressor of interest revealed increased activity in the temporal pole, a region related to value discrimination. Results suggest sign-tracking is associated with activation of the 'attention and salience network' in response to reward cues but not reward feedback, suggesting parcellation between the two at the level of the brain. Results add to the literature showing considerable overlap in neural systems implicated in reward processing, learning, habit formation, emotion regulation and substance craving.

Diminishing sensitivity and absolute difference in value-driven attention

Kim and Beck (2020b) demonstrated that value-driven attention is based on relative value rather than absolute value, suggesting that prospect theory is relevant to our understanding of value-driven attention. To further this understanding, the present study investigated the impacts of diminishing sensitivity on value-driven attention. According to diminishing sensitivity, changes in outcomes have greater impacts nearer the reference point of 0 than farther from the point. Thus, the difference between $1 and $100 looms larger than that between $901 and $1000, due to their different ratios (100/1 > 1000/901). However, according to the absolute difference hypothesis, the differences should have similar impacts due to the absolute differences being the same (100 – 1 = 1000 – 901). Experiment 1 investigated whether diminishing sensitivity operates in the modified value-driven attention paradigm while controlling the impact of absolute differences. In the training phase, 100-point and 1000-point color targets had references of 1-point and 901-point color targets, respectively. In the test phase, 100-point color distractors attracted attention more than 1000-point color distractors, supporting the diminishing sensitivity hypothesis. Experiment 2 examined the absolute difference hypothesis while controlling the impact of diminishing sensitivity. Contrary to the absolute difference hypothesis, the test phase showed that 1000-point color distractors (compared with 10-point colors for a 990 absolute difference in the training phase) failed to attract attention more than 100-point color distractors (compared with 1-point colors, for a 99 absolute difference). These results suggest that diminishing sensitivity rather than absolute difference influences value-driven attention, further supporting the relevance of prospect theory to value-driven attention.

Value-Biased Competition in the Auditory System of the Brain

Attentional capture by previously reward-associated stimuli has predominantly been measured in the visual domain. Recently, behavioral studies of value-driven attention have demonstrated involuntary attentional capture by previously reward-associated sounds, emulating behavioral findings within the visual domain and suggesting a common mechanism of attentional capture by value across sensory modalities. However, the neural correlates of the modulatory role of learned value on the processing of auditory information has not been examined. Here, we conducted a neuroimaging study on human participants using a previously established behavioral paradigm that measures value-driven attention in an auditory target identification task. We replicate behavioral findings of both voluntary prioritization and involuntary attentional capture by previously reward-associated sounds. When task-relevant, the selective processing of high-value sounds is supported by reduced activation in the dorsal attention network of the visual system (FEF, intraparietal sulcus, right middle frontal gyrus), implicating cross-modal processes of biased competition. When task-irrelevant, in contrast, high-value sounds evoke elevated activation in posterior parietal cortex and are represented with greater fidelity in the auditory cortex. Our findings reveal two distinct mechanisms of prioritizing reward-related auditory signals, with voluntary and involuntary modes of orienting that are differently manifested in biased competition.

Value-based cognition and drug dependency

Value-based decision-making is thought to play an important role in drug dependency. Achieving elevated levels of euphoria or ameliorating dysphoria/pain may motivate goal-directed drug consumption in both drug-naïve and long-time users. In other words, drugs become viewed as the preferred means of attaining a desired internal state. The bias towards choosing drugs may affect one's cognition. Observed biases in learning, attention and memory systems within the brain gradually focus one's cognitive functions towards drugs and related cues to the exclusion of other stimuli. In this narrative review, the effects of drug use on learning, attention and memory are discussed with a particular focus on changes across brain-wide functional networks and the subsequent impact on behaviour. These cognitive changes are then incorporated into the cycle of addiction, an established model outlining the transition from casual drug use to chronic dependency. If drug use results in the elevated salience of drugs and their cues, the studies highlighted in this review strongly suggest that this salience biases cognitive systems towards the motivated pursuit of addictive drugs. This bias is observed throughout the cycle of addiction, possibly contributing to the persistent hold that addictive drugs have over the dependent. Taken together, the excessive valuation of drugs as the preferred means of achieving a desired internal state affects more than just decision-making, but also learning, attentional and mnemonic systems. This eventually narrows the focus of one's thoughts towards the pursuit and consumption of addictive drugs.

Motivational Salience Guides Attention to Valuable and Threatening Stimuli: Evidence from Behavior and Functional Magnetic Resonance Imaging

Rewarding and aversive outcomes have opposing effects on behavior, facilitating approach and avoidance, although we need to accurately anticipate each type of outcome to behave effectively. Attention is biased toward stimuli that have been learned to predict either type of outcome, and it remains an open question whether such orienting is driven by separate systems for value- and threat-based orienting or whether there exists a common underlying mechanism of attentional control driven by motivational salience. Here, we provide a direct comparison of the neural correlates of value- and threat-based attentional capture after associative learning. Across multiple measures of behavior and brain activation, our findings overwhelmingly support a motivational salience account of the control of attention. We conclude that there exists a core mechanism of experience-dependent attentional control driven by motivational salience and that prior characterizations of attention as being value driven or supporting threat monitoring need to be revisited.

The past, present, and future of selection history

The last ten years of attention research have witnessed a revolution, replacing a theoretical dichotomy (top-down vs. bottom-up control) with a trichotomy (biased by current goals, physical salience, and selection history). This third new mechanism of attentional control, selection history, is multifaceted. Some aspects of selection history must be learned over time whereas others reflect much more transient influences. A variety of different learning experiences can shape the attention system, including reward, aversive outcomes, past experience searching for a target, target‒non-target relations, and more. In this review, we provide an overview of the historical forces that led to the proposal of selection history as a distinct mechanism of attentional control. We then propose a formal definition of selection history, with concrete criteria, and identify different components of experience-driven attention that fit within this definition. The bulk of the review is devoted to exploring how these different components relate to one another. We conclude by proposing an integrative account of selection history centered on underlying themes that emerge from our review.

Exploring reward-related attention selectivity deficits in Parkinson's disease

An important aspect of managing a limited cognitive resource like attention is to use the reward value of stimuli to prioritize the allocation of attention to higher-value over lower-value stimuli. Recent evidence suggests this depends on dopaminergic signaling of reward. In Parkinson's disease, both reward sensitivity and attention are impaired, but whether these deficits are directly related to one another is unknown. We tested whether Parkinson's patients use reward information when automatically allocating their attention and whether this is modulated by dopamine replacement. We compared patients, tested both ON and OFF dopamine replacement medication, to older controls using a standard attention capture task. First, participants learned the different reward values of stimuli. Then, these reward-associated stimuli were used as distractors in a visual search task. We found that patients were generally distracted by the presence of the distractors but that the degree of distraction caused by the high-value and low-value distractors was similar. Furthermore, we found no evidence to support the possibility that dopamine replacement modulates the effect of reward on automatic attention allocation. Our results suggest a possible inability in Parkinson's patients to use the reward value of stimuli when automatically allocating their attention, and raise the possibility that reward-driven allocation of resources may affect the adaptive modulation of other cognitive processes.

Neurochemistry of Visual Attention

Visual attention is the cognitive process that mediates the selection of important information from the environment. This selection is usually controlled by bottom-up and top-down attentional biasing. Since for most humans vision is the dominant sense, visual attention is critically important for higher-order cognitive functions and related deficits are a core symptom of many neuropsychiatric and neurological disorders. Here, we summarize the importance and relative contributions of different neuromodulators and neurotransmitters to the neural mechanisms of top-down and bottom-up attentional control. We will not only review the roles of widely accepted neuromodulators, such as acetylcholine, dopamine and noradrenaline, but also the contributions of other modulatory substances. In doing so, we hope to shed some light on the current understanding of the role of neurochemistry in shaping neuron properties contributing to the allocation of attention in the visual field.

Decreased modulation of segregated SEEKING and selective attention systems in chronic insomnia

Sleep-related attentional bias and instinctual craving-sleep status may be associated with value-driven selective attention network and SEEKING system. We hypothesized that the two networks might be important components and underlie etiology of inability to initiate or/and maintain sleep in patients with chronic insomnia (PIs). Our aim is to investigate whether frequency-frequency couplings(temporal and spatial coupling, and differences of a set of imaging parameters) could elevate the sensibility to characterize the two insomnia-related networks in studying their relationships with sleep parameters and post-insomnia emotions. Forty-eight PIs and 48 status-matched good sleepers were requested to complete sleep and emotion-related questionnaires. Receiver operating characteristic curve was used to calculate the discriminatory power of a set of parameters. Granger causality and mediating causality analysis were used to address the causal relationships between the two networks and sleep/emotion-related parameters. Frequency-frequency couplings could characterize the two networks with high discriminatory power (AUC, 0.951; sensitivity, 87.5%; specificity, 95.8%), which suggested that the frequency-frequency couplings could be served as a useful biomarker to address the insomnia-related brain networks. Functional deficits of the SEEKING system played decreased mediator acting in post-insomnia negative emotions (decreased frequency-frequency coupling). Functional hyperarousal of the value-driven attention network played decreased mediator acting in sleep regulation (increased frequency-frequency coupling). Granger causality analysis showed decreased causal effect connectivity between and within the two networks. The between-network causal effect connectivity segregation played decreased mediator acting in sleep regulation (decreased connectivity). These findings suggest that the functional deficits and segregation of the two systems may underlie etiology of PIs.

Dopamine 'ups and downs' in addiction revisited

Repeated drug use can change dopamine (DA) function in ways that promote the development and persistence of addiction, but in what direction? By one view, drug use blunts DA neurotransmission, producing a hypodopaminergic state that fosters further drug use to overcome a DA deficiency. Another view is that drug use enhances DA neurotransmission, producing a sensitized, hyperdopaminergic reaction to drugs and drug cues. According to this second view, continued drug use is motivated by sensitization of drug 'wanting'. Here we discuss recent evidence supporting the latter view, both from preclinical studies using intermittent cocaine self-administration procedures that mimic human patterns of use and from related human neuroimaging studies. These studies have implications for the modeling of addiction in the laboratory and for treatment.

Stimulus-response learning and expected reward value enhance stimulus cognitive processing: An ERP study

Reward affects our attention to stimuli, prioritizing those that lead to high-value outcomes. Recently, it has been suggested that such reward-related cognitive prioritization might be associated with the process of learning new stimulus-response (S-R) associations, because both are acquired through extended reward training, and once established, they are hard to overcome. We used event-related potentials (ERP) to analyze the contribution of S-R links to the formation of reward-related cognitive prioritization during reinforcement learning. Reward-related cognitive prioritization was measured by comparing the ERP signals for stimuli predicting high-value and low-value outcomes. In addition, we compared a strong S-R link (same stimulus, same response), with a weak S-R link condition (same stimulus, two different responses). The participants' performance was more accurate and faster when the procedure allowed for establishing strong S-R links and for high-value outcomes. Furthermore, those stimuli associated with strong S-R links showed a larger P3 amplitude at parietal sites. Value effects (larger ERP activity for those stimuli predicting a high-value outcome) were obtained at parietal and occipital sites in the P3 time window. However, value effects did not benefit from strong S-R links in either the P1 or the P3 components. These results suggest that strong S-R learning is not necessary to develop reward-related modulations of ERP activity.

Beyond Looking for the Rewarded Target: The Effects of Reward on Attention in Search Tasks

One puzzling result in training-test paradigms is that effects of reward-associated stimuli on attention are often seen in test but not in training. We focus on one study, where reward-related performance benefits occur in the training and which was discussed contentiously. By using a similar design, we conceptually replicated the results. Moreover, we investigated the underlying mechanisms and processes resulting in these reward-related performance benefits. In two experiments, using search tasks and having participants perform the tasks either with or without individually adjusted time pressure, we disentangled the mechanisms and processes contributing to the reward-related benefits. We found evidence that not only search efficiency is increased with increasing reward, but also that non-search factors contribute to the results. By also investigating response time distributions, we were able to show that reward-related performance effects increased as search time increased in demanding tasks but not in less demanding tasks. Theoretical implications of the results regarding how reward influences attentional processing are discussed.

Reward makes the rhythmic sampling of spatial attention emerge earlier

A growing body of evidence demonstrates a rhythmic characteristic of spatial attention, with the corresponding behavioral performance fluctuating periodically. Here, we investigate whether and how the rhythmic characteristic of spatial attention is affected by reward-an important factor in attentional selection. We adopted the classic spatial cueing paradigm with a time-resolved stimulus-onset-asynchrony (SOA) between the spatial cue and the target such that responses to the target in different phases could be examined. The color of the spatial cue was associated with either a high or low level of reward. Results showed that in the low-frequency band (<2 Hz) where classic exogenous spatial attention effects (i.e., facilitation and inhibition of return; IOR) appeared, reward enhanced the late IOR effect through facilitating behavioral responses to the target at the uncued location. Recurring lower alpha power (alpha inhibition) which fluctuated in a low-theta frequency (2-3 Hz) was observed at the cued location relative to the uncued location, irrespective of the reward level of the cue. Importantly, the recurring alpha inhibition emerged earlier (~120 ms) in the high-reward condition relative to the low-reward condition. We propose that the recurring alpha inhibition at the cued location implies a recurring attention sampling at the cued location and the expectation of a high reward makes the periodic attention sampling emerge earlier.

Effects of reward associations on components of attentional network

Previous research has revealed the influence of reward associations on attentional selection and control. The attentional network can be divided into three components according to its function: Alerting, orienting, and executive control. In the current research, we used training-test procedure and attention network test variant to investigate the effects of color-based reward associations on alerting (Experiment 1), orienting (Experiment 2), executive control (Experiment 3), as well as the interactions among these three networks (Experiment 4). The findings were as follows: Compared with colors previously associated with low reward, colors previously associated with high reward trigger stronger alerting and orienting effects (Experiments 1 and 2), and they had stronger interference effects when functioning as features of flanker distractor (Experiment 3). More importantly, reward associations had only a positive impact on the interaction of orienting by executive control but not on the interaction of alerting by executive control (Experiment 4). In summary, reward associations have different effects on the three attentional networks and can enhance the interaction of orienting by executive control.

History of conditioned reward association disrupts inhibitory control: an examination of neural correlates

The neural processes that support inhibitory control in the face of stimuli with a history of reward association are not yet well understood. Yet, the ability to flexibly adapt behavior to changing reward-contingency contexts is important for daily functioning and warrants further investigation. This study aimed to characterize neural and behavioral impacts of stimuli with a history of conditioned reward association on motor inhibitory control in healthy young adults by investigating group-level effects as well as individual variation in the ability to inhibit responses to stimuli with a reward history. Participants (N = 41) first completed a reward conditioning phase, during which responses to rewarded stimuli were associated with money and responses to unrewarded stimuli were not. Rewarded and unrewarded stimuli from training were carried forward as No-Go targets in a subsequent go/no-go task to test the effect of reward history on inhibitory control. Participants underwent functional brain imaging during the go/no-go portion of the task. On average, a history of reward conditioning disrupted inhibitory control. Compared to inhibition of responses to stimuli with no reward history, trials that required inhibition of responses to previously rewarded stimuli were associated with greater activity in frontal and striatal regions, including the inferior frontal gyrus, insula, striatum, and thalamus. Activity in the insula and thalamus during false alarms and in the ventromedial prefrontal cortex during correctly withheld trials predicted behavioral performance on the task. Overall, these results suggest that reward history serves to disrupt inhibitory control and provide evidence for diverging roles of the insula and ventromedial prefrontal cortex while inhibiting responses to stimuli with a reward history.

Inertia in value-driven attention

Previously reward-associated stimuli persistently capture attention. We attempted to extinguish this attentional bias through a reversal learning procedure where the high-value color changed unexpectedly. Attentional priority shifted during training in favor of the currently high-value color, although a residual bias toward the original high-value color was still evident. Importantly, during a subsequent test phase, attention was initially more strongly biased toward the original high-value color, counter to the attentional priorities evident at the end of training. Our results show that value-based attentional biases do not quickly update with new learning and lag behind the reshaping of strategic attentional priorities by reward.

Differential Deployment of Visual Attention During Interactive Approach and Avoidance Behavior

The ability to coordinate approach and avoidance actions in dynamic environments represents the boundary between extinction and the continued survival of many animal species. It is therefore crucial that sensory systems allocate limited attentional resources to the most relevant information to facilitate planning and execution of appropriate actions. Prominent theories of how attention regulates visual processing focus on the distinction between behaviorally relevant and irrelevant visual inputs. To date, however, no study has directly compared the deployment of attention to visual inputs relevant for approach and avoidance behaviors, which naturally occur in dynamic, interactive environments. In two experiments, we combined electroencephalography, frequency tagging, and eye gaze measures to investigate whether the deployment of visual selective attention differs for items relevant for approach and avoidance actions. Participants maneuvered a cursor to approach and avoid contact with moving items in a continuous interactive task. The results indicated that while the approach and avoidance tasks recruited equivalent attentional resources overall, attentional biases were directed toward task-relevant items during approach, and away from task-relevant items during avoidance. We conclude that the deployment of visual attention is guided not only by relevance to a behavioral goal, but also by the nature of that goal.

Visual stimuli induce serotonin release in occipital cortex: A simultaneous positron emission tomography/magnetic resonance imaging study

Endogenous serotonin (5-HT) release can be measured noninvasively using positron emission tomography (PET) imaging in combination with certain serotonergic radiotracers. This allows us to investigate effects of pharmacological and nonpharmacological interventions on brain 5-HT levels in living humans. Here, we study the neural responses to a visual stimulus using simultaneous PET/MRI. In a cross-over design, 11 healthy individuals were PET/MRI scanned with the 5-HT_1B receptor radioligand [¹¹ C]AZ10419369, which is sensitive to changes in endogenous 5-HT. During the last part of the scan, participants either viewed autobiographical images with positive valence (n = 11) or kept their eyes closed (n = 7). The visual stimuli increased cerebral blood flow (CBF) in the occipital cortex, as measured with pseudo-continuous arterial spin labeling. Simultaneously, we found decreased 5-HT_1B receptor binding in the occipital cortex (-3.6 ± 3.6%), indicating synaptic 5-HT release. Using a linear regression model, we found that the change in 5-HT_1B receptor binding was significantly negatively associated with change in CBF in the occipital cortex (p = .004). For the first time, we here demonstrate how cerebral 5-HT levels change in response to nonpharmacological stimuli in humans, as measured with PET. Our findings more directly support a link between 5-HT signaling and visual processing and/or visual attention.

Relating value-driven attention to psychopathology

Reward-associated objects receive preferential attention, reflecting a bias in information processing that develops automatically following associative learning. Mounting evidence suggests that such value-driven attention operates abnormally in certain psychopathologies, with attentional biases for reward-associated objects being either exaggerated or blunted compared to healthy controls. Here, I review the evidence linking value-driven attention to psychopathology, including drug addiction, depression, attention-deficit hyperactivity disorder (ADHD), compulsivity, and impulsive and risky decision-making. I conclude by offering an integrative framework for conceptualizing the link between value-driven attention and psychopathology, along with suggestions for future research into this burgeoning area of investigation, including research on object attachment.

Arousal-Biased Competition Explains Reduced Distraction by Reward Cues under Threat

Anxiety is an adaptive neural state that promotes rapid responses under heightened vigilance when survival is threatened. Anxiety has consistently been found to potentiate the attentional processing of physically salient stimuli. However, a recent study demonstrated that a threat manipulation reduces attentional capture by reward-associated stimuli, suggesting a more complex relationship between anxiety and the control of attention. The mechanisms by which threat can reduce the distracting quality of stimuli are unknown. In this study, using functional magnetic resonance imaging (fMRI) on human subjects, we examined the neural correlates of attention to previously reward-associated stimuli with and without the threat of unpredictable electric shock. We replicate enhanced distractor-evoked activity throughout the value-driven attention network (VDAN) in addition to enhanced stimulus-evoked activity generally under threat. Importantly, these two factors interacted such that the representation of previously reward-associated distractors was particularly pronounced under threat. Our results from neuroimaging fit well with the principle of arousal-biased competition (ABC), although such effects are typically associated with behavioral measures of increased attention to stimuli that already possess elevated attentional priority. The findings of our study suggest that ABC can be leveraged to support more efficient ignoring of reward cues, revealing new insights into the functional significance of ABC as a mechanism of attentional control, and provide a mechanistic explanation of how threat reduces attention to irrelevant reward information.

Value-based attention capture: Differential effects of loss and gain contingencies

There is evidence that attention can be captured by a feature that is associated with reward. However, it is unclear how associating a feature with loss impacts attentional capture. Some have found evidence for attentional capture by loss-associated stimuli, suggesting that attention is biased toward stimuli predictive of consequence, regardless of the valence of that consequence. However, in those studies, efficient attention to the loss-associated stimulus reduced the magnitude of the loss during training, so attention to the loss-associated stimulus was rewarded in relative terms. In Experiment 1 we associated a color with loss, gain, or no consequence during training and then investigated whether attention is captured by each color. Importantly, our training did not reward, even in a relative sense, attention to the loss-associated color. Although we found robust attentional capture by gain-associated colors, we found no evidence for capture by loss-associated colors. A second experiment showed that the observed effects cannot be explained by selection history and, hence, are specific to value learning. These results suggest that the learning mechanisms of value-based attentional capture are driven by reward, but not by loss or the predictability of consequences in general.

Reward-Related Suppression of Neural Activity in Macaque Visual Area V4

In order for organisms to survive, they need to detect rewarding stimuli, for example, food or a mate, in a complex environment with many competing stimuli. These rewarding stimuli should be detected even if they are nonsalient or irrelevant to the current goal. The value-driven theory of attentional selection proposes that this detection takes place through reward-associated stimuli automatically engaging attentional mechanisms. But how this is achieved in the brain is not very well understood. Here, we investigate the effect of differential reward on the multiunit activity in visual area V4 of monkeys performing a perceptual judgment task. Surprisingly, instead of finding reward-related increases in neural responses to the perceptual target, we observed a large suppression at the onset of the reward indicating cues. Therefore, while previous research showed that reward increases neural activity, here we report a decrease. More suppression was caused by cues associated with higher reward than with lower reward, although neither cue was informative about the perceptually correct choice. This finding of reward-associated neural suppression further highlights normalization as a general cortical mechanism and is consistent with predictions of the value-driven attention theory.

Orbitofrontal cortex is selectively activated in a primate model of attentional bias to cocaine cues

Attentional bias to drug-associated cues correlates with extent of current use, and risk of relapse among those attempting abstinence. Electroencephalogram (EEG) and functional imaging measures in clinical studies have previously investigated the neural basis of attentional bias, but the lack of animal models precluded investigation at the single-unit level. To complement results obtained from clinical studies, we have employed a non-human primate model of attentional bias to cocaine cues while simultaneously recording single-unit activity in cortical and striatal regions implicated in reward processing. Rhesus macaques conditioned to associate particular colors with cocaine or water reward performed an attentional bias task, in which those colors served as irrelevant distractors. Concurrently, multiple electrode arrays for recording single-unit activity were acutely implanted into the orbitofrontal cortex, anterior cingulate cortex, dorsal anterior striatum, and ventral striatum. As in clinical studies, attentional bias was indicated by elongated response times on trials with cocaine-associated distractors compared with trials with water-associated, or control unconditioned distractors. In both animals studied, across an unbiased sample of neurons, the orbitofrontal cortex differentiated distractor condition by the proportion of single-units activated, as well as by population response. In one of the two, the anterior cingulate cortex did as well, but neither striatal region did in either animal. These direct measures of single-unit activity in a primate model complement clinical imaging observations suggesting that cortical mechanisms, especially in orbitofrontal cortex, are likely involved in attentional bias to cocaine-associated environmental cues.

Emotional Objectivity: Neural Representations of Emotions and Their Interaction with Cognition

Recent advances in our understanding of information states in the human brain have opened a new window into the brain's representation of emotion. While emotion was once thought to constitute a separate domain from cognition, current evidence suggests that all events are filtered through the lens of whether they are good or bad for us. Focusing on new methods of decoding information states from brain activation, we review growing evidence that emotion is represented at multiple levels of our sensory systems and infuses perception, attention, learning, and memory. We provide evidence that the primary function of emotional representations is to produce unified emotion, perception, and thought (e.g., “That is a good thing”) rather than discrete and isolated psychological events (e.g., “That is a thing. I feel good”). The emergent view suggests ways in which emotion operates as a fundamental feature of cognition, by design ensuring that emotional outcomes are the central object of perception, thought, and action.

Thalamic degeneration in MPTP-treated Parkinsonian monkeys: impact upon glutamatergic innervation of striatal cholinergic interneurons

In both Parkinson's disease (PD) patients and MPTP-treated non-human primates, there is a profound neuronal degeneration of the intralaminar centromedian/parafascicular (CM/Pf) thalamic complex. Although this thalamic pathology has long been established in PD (and other neurodegenerative disorders), the impact of CM/Pf cell loss on the integrity of the thalamo-striatal glutamatergic system and its regulatory functions upon striatal neurons remain unknown. In the striatum, cholinergic interneurons (ChIs) are important constituents of the striatal microcircuitry and represent one of the main targets of CM/Pf-striatal projections. Using light and electron microscopy approaches, we have analyzed the potential impact of CM/Pf neuronal loss on the anatomy of the synaptic connections between thalamic terminals (vGluT2-positive) and ChIs neurons in the striatum of parkinsonian monkeys treated chronically with MPTP. The following conclusions can be drawn from our observations: (1) as reported in PD patients, and in our previous monkey study, CM/Pf neurons undergo profound degeneration in monkeys chronically treated with low doses of MPTP. (2) In the caudate (head and body) nucleus of parkinsonian monkeys, there is an increased density of ChIs. (3) Despite the robust loss of CM/Pf neurons, no significant change was found in the density of thalamostriatal (vGluT2-positive) terminals, and in the prevalence of vGluT2-positive terminals in contact with ChIs in parkinsonian monkeys. These findings provide new information about the state of thalamic innervation of the striatum in parkinsonian monkeys with CM/Pf degeneration, and bring up an additional level of intricacy to the consequences of thalamic pathology upon the functional microcircuitry of the thalamostriatal system in parkinsonism. Future studies are needed to assess the importance of CM/Pf neuronal loss, and its potential consequences on the neuroplastic changes induced in the synaptic organization of the thalamostriatal system, in the development of early cognitive impairments in PD.

Reward learning biases the direction of saccades

The role of associative reward learning in guiding feature-based attention and spatial attention is well established. However, no studies have looked at the extent to which reward learning can modulate the direction of saccades during visual search. Here, we introduced a novel reward learning paradigm to examine whether reward-associated directions of eye movements can modulate performance in different visual search tasks. Participants had to fixate a peripheral target before fixating one of four disks that subsequently appeared in each cardinal position. This was followed by reward feedback contingent upon the direction chosen, where one direction consistently yielded a high reward. Thus, reward was tied to the direction of saccades rather than the absolute location of the stimulus fixated. Participants selected the target in the high-value direction on the majority of trials, demonstrating robust learning of the task contingencies. In an untimed visual foraging task that followed, which was performed in extinction, initial saccades were reliably biased in the previously rewarded-associated direction. In a second experiment, following the same training procedure, eye movements in the previously high-value direction were facilitated in a saccade-to-target task. Our findings suggest that rewarding directional eye movements biases oculomotor search patterns in a manner that is robust to extinction and generalizes across stimuli and task.

Transcranial Recording of Electrophysiological Neural Activity in the Rodent Brain in vivo Using Functional Photoacoustic Imaging of Near-Infrared Voltage-Sensitive Dye

Minimally-invasive monitoring of electrophysiological neural activities in real-time-that enables quantification of neural functions without a need for invasive craniotomy and the longer time constants of fMRI and PET-presents a very challenging yet significant task for neuroimaging. In this paper, we present in vivo functional PA (fPA) imaging of chemoconvulsant rat seizure model with intact scalp using a fluorescence quenching-based cyanine voltage-sensitive dye (VSD) characterized by a lipid vesicle model mimicking different levels of membrane potential variation. The framework also involves use of a near-infrared VSD delivered through the blood-brain barrier (BBB), opened by pharmacological modulation of adenosine receptor signaling. Our normalized time-frequency analysis presented in vivo VSD response in the seizure group significantly distinguishable from those of the control groups at sub-mm spatial resolution. Electroencephalogram (EEG) recording confirmed the changes of severity and frequency of brain activities, induced by chemoconvulsant seizures of the rat brain. The findings demonstrate that the near-infrared fPA VSD imaging is a promising tool for in vivo recording of brain activities through intact scalp, which would pave a way to its future translation in real time human brain imaging.

Imaging striatal dopamine release using a nongenetically encoded near infrared fluorescent catecholamine nanosensor

Neuromodulation plays a critical role in brain function in both health and disease, and new tools that capture neuromodulation with high spatial and temporal resolution are needed. Here, we introduce a synthetic catecholamine nanosensor with fluorescent emission in the near infrared range (1000-1300 nm), near infrared catecholamine nanosensor (nIRCat). We demonstrate that nIRCats can be used to measure electrically and optogenetically evoked dopamine release in brain tissue, revealing hotspots with a median size of 2 µm. We also demonstrated that nIRCats are compatible with dopamine pharmacology and show D2 autoreceptor modulation of evoked dopamine release, which varied as a function of initial release magnitude at different hotspots. Together, our data demonstrate that nIRCats and other nanosensors of this class can serve as versatile synthetic optical tools to monitor neuromodulatory neurotransmitter release with high spatial resolution.

Measuring attention to reward as an individual trait: the value-driven attention questionnaire (VDAQ)

Reward history is a powerful determinant of what we pay attention to. This influence of reward on attention varies substantially across individuals, being related to a variety of personality variables and clinical conditions. Currently, the ability to measure and quantify attention-to-reward is restricted to the use of psychophysical laboratory tasks, which limits research into the construct in a variety of ways. In the present study, we introduce a questionnaire designed to provide a brief and accessible means of assessing attention-to-reward. Scores on the questionnaire correlate with other measures known to be related to attention-to-reward and predict performance on multiple laboratory tasks measuring the construct. In demonstrating this relationship, we also provide evidence that attention-to-reward as measured in the lab, an automatic and implicit bias in information processing, is related to overt behaviors and motivations in everyday life as assessed via the questionnaire. Variation in scores on the questionnaire is additionally associated with a distinct biomarker in brain connectivity, and the questionnaire exhibits acceptable test-retest reliability. Overall, the Value-Driven Attention Questionnaire (VDAQ) provides a useful proxy-measure of attention-to-reward that is much more accessible than typical laboratory assessments.

Effects of methamphetamine on neural responses to visual stimuli

RATIONALE

The behavioral and reward-related effects of stimulant drugs have been studied extensively; yet the effect of stimulants on sensory processing is still relatively unknown. Prior brain imaging studies have shown that single doses of stimulant drugs increase neural function during cognitive and attentional processes. However, it is not clear if stimulant drugs such as methamphetamine (MA) affect neural responses to novel sensory stimuli, and whether these effects depend on the visual features of the stimuli.

OBJECTIVE

In this study, we examined the effects of a single dose of MA (20 mg oral) on neural activation in response to visual stimuli that varied on "non-straight edges" (NSE), a low-level visual feature that quantifies curved/fragmented edges and is related to perceived image complexity.

METHODS

Healthy adult participants (n = 18) completed two sessions in which they received MA and placebo in counterbalanced order before an fMRI scan where they viewed both high and low NSE images. Participants also completed measures of subjective drug effects throughout both sessions.

RESULTS

During both sessions, high NSE images activated primary visual cortex to a greater extent than low NSE images. Further, MA increased activation only for low NSE images in three areas of visual association cortex: left fusiform, right cingulate/precuneus, and posterior right middle temporal gyrus. This interaction was unrelated to subjective drug effects.

CONCLUSIONS

These findings suggest that stimulant drugs may change the relative sensitivity of higher order sensory processing to increase visual attention when viewing less complex stimuli. Moreover, MA-induced alterations in this type of sensory processing appear to be independent of the drugs' ability to increase feelings of well-being.

On the relationship between value-driven and stimulus-driven attentional capture

Reward history, physical salience, and task relevance all influence the degree to which a stimulus competes for attention, reflecting value-driven, stimulus-driven, and goal-contingent attentional capture, respectively. Theories of value-driven attention have likened reward cues to physically salient stimuli, positing that reward cues are preferentially processed in early visual areas as a result of value-modulated plasticity in the visual system. Such theories predict a strong coupling between value-driven and stimulus-driven attentional capture across individuals. In the present study, we directly test this hypothesis, and demonstrate a robust correlation between value-driven and stimulus-driven attentional capture. Our findings suggest substantive overlap in the mechanisms of competition underlying the attentional priority of reward cues and physically salient stimuli.

Value-driven attentional capture is modulated by the contents of working memory: An EEG study

Attention and working memory (WM) have previously been shown to interact closely when sensory information is being maintained. However, when non-sensory information is maintained in WM, the relationship between WM and sensory attention may be less strong. In the current study, we used electroencephalography to evaluate whether value-driven attentional capture (i.e., allocation of attention to a task-irrelevant feature previously associated with a reward) and its effects on either sensory or non-sensory WM performance might be greater than the effects of salient, non-reward-associated stimuli. In a training phase, 19 participants learned to associate a color with reward. Then, participants were presented with squares and encoded their locations into WM. Participants were instructed to convert the spatial locations either to another type of sensory representation or to an abstract, relational type of representation. During the WM delay period, task-irrelevant distractors, either previously-rewarded or non-rewarded, were presented, with a novel color distractor in the other hemifield. The results revealed lower alpha power and larger N2pc amplitude over posterior electrode sides contralateral to the previously rewarded color, compared to ipsilateral. These effects were mainly found during relational WM, compared to sensory WM, and only for the previously rewarded distractor color, compared to a previous non-rewarded target color or novel color. These effects were associated with modulations of WM performance. These results appear to reflect less capture of attention during maintenance of specific location information, and suggest that value-driven attentional capture can be mitigated as a function of the type of information maintained in WM.

Neural evidence for automatic value-modulated approach behaviour

Reward learning has the ability to bias both attention and behaviour. The current study presents behavioural and neural evidence that irrelevant responses evoked by previously reward-associated stimuli are more robustly represented in the motor system using a combined go/no-go and flankers task. Following a colour-reward association training, participants were instructed to respond to a central target only in a response-relevant context, while ignoring flankers that appeared either in a high-value or low-value colour. The motor cortex and cerebellum exhibited reduced activation to low-value flankers in a response-irrelevant context, consistent with goal-directed response suppression. However, these same regions exhibited similar activation to high-value flankers regardless of their response relevance, indicating less effective suppression, and the resulting interaction in motor cortex activation was strongly predicted by the influence of the flankers on behaviour. These findings suggest that associative reward learning produces a general approach bias, which is particularly evident when it conflicts with task goals, extending the principle of value-driven attention to stimulus-evoked responses in the motor system.