Biased Competition Research Articles

Visual Perception: Early Visual Cortex Fills in the Gaps

A new human fMRI study shows how early visual cortex makes sense of complex visual scenes by segregating foreground and background, and by highlighting outlier objects. The findings are consistent with two attractive theories: biased competition and predictive coding.

Objects tell us what action we can expect: dissociating brain areas for retrieval and exploitation of action knowledge during action observation in fMRI.

Objects are reminiscent of actions often performed with them: knife and apple remind us on peeling the apple or cutting it. Mnemonic representations of object-related actions (action codes) evoked by the sight of an object may constrain and hence facilitate recognition of unrolling actions. The present fMRI study investigated if and how action codes influence brain activation during action observation. The average number of action codes (NAC) of 51 sets of objects was rated by a group of n = 24 participants. In an fMRI study, different volunteers were asked to recognize actions performed with the same objects presented in short videos. To disentangle areas reflecting the storage of action codes from those exploiting them, we showed object-compatible and object-incompatible (pantomime) actions. Areas storing action codes were considered to positively co-vary with NAC in both object-compatible and object-incompatible action; due to its role in tool-related tasks, we here hypothesized left anterior inferior parietal cortex (aIPL). In contrast, areas exploiting action codes were expected to show this correlation only in object-compatible but not incompatible action, as only object-compatible actions match one of the active action codes. For this interaction, we hypothesized ventrolateral premotor cortex (PMv) to join aIPL due to its role in biasing competition in IPL. We found left anterior intraparietal sulcus (IPS) and left posterior middle temporal gyrus (pMTG) to co-vary with NAC. In addition to these areas, action codes increased activity in object-compatible action in bilateral PMv, right IPS, and lateral occipital cortex (LO). Findings suggest that during action observation, the brain derives possible actions from perceived objects, and uses this information to shape action recognition. In particular, the number of expectable actions quantifies the activity level at PMv, IPL, and pMTG, but only PMv reflects their biased competition while observed action unfolds.

Snake fearfulness is associated with sustained competitive biases to visual snake features: Hypervigilance without avoidance

The extent and time course of competition between a specific fear cue and task-related stimuli in early human visual cortex was investigated using electrophysiology. Steady-state visual evoked potentials (ssVEPs) were evoked using random-dot kinematograms that consisted of rapidly flickering (8.57Hz) dots moving randomly, superimposed upon emotional or neutral distractor pictures. Participants were asked to detect intervals of coherently moving dots, ignoring the distractor pictures that varied in hedonic content. Women reporting high or low levels of snake fear were recruited from a large sample of healthy college students, and snake pictures served as fear-relevant distractors. The time-varying amplitude of the ssVEP evoked by the motion detection task showed significant reduction when viewing emotionally arousing, compared to neutral, distractors, replicating previous studies. For high-fear participants, snake distractors elicited a sustained attenuation of task evoked ssVEP amplitude, greater than the attenuation prompted by other unpleasant arousing content. These findings support a hypothesis that fear cues prompt sustained hypervigilance rather than perceptual avoidance.

A dual process for the cognitive control of emotional significance: implications for emotion regulation and disorders of emotion

A dual process for the cognitive control of emotional significance: implications for emotion regulation and disorders of emotion

Neural Mechanisms Underlying Visual Short-Term Memory Gain for Temporally Distinct Objects

Recent research has shown that visual short-term memory (VSTM) can substantially be improved when the to-be-remembered objects are split in 2 half-arrays (i.e., sequenced) or the entire array is shown twice (i.e., repeated), rather than presented simultaneously. Here we investigate the hypothesis that sequencing and repeating displays overcomes attentional "bottlenecks" during simultaneous encoding. Using functional magnetic resonance imaging, we show that sequencing and repeating displays increased brain activation in extrastriate and primary visual areas, relative to simultaneous displays (Study 1). Passively viewing identical stimuli did not increase visual activation (Study 2), ruling out a physical confound. Importantly, areas of the frontoparietal attention network showed increased activation in repetition but not in sequential trials. This dissociation suggests that repeating a display increases attentional control by allowing attention to be reallocated in a second encoding episode. In contrast, sequencing the array poses fewer demands on control, with competition from nonattended objects being reduced by the half-arrays. This idea was corroborated by a third study in which we found optimal VSTM for sequential displays minimizing attentional demands. Importantly these results provide support within the same experimental paradigm for the role of stimulus-driven and top-down attentional control aspects of biased competition theory in setting constraints on VSTM.

Emotional arousal amplifies the effects of biased competition in the brain

The arousal-biased competition model predicts that arousal increases the gain on neural competition between stimuli representations. Thus, the model predicts that arousal simultaneously enhances processing of salient stimuli and impairs processing of relatively less-salient stimuli. We tested this model with a simple dot-probe task. On each trial, participants were simultaneously exposed to one face image as a salient cue stimulus and one place image as a non-salient stimulus. A border around the face cue location further increased its bottom-up saliency. Before these visual stimuli were shown, one of two tones played: one that predicted a shock (increasing arousal) or one that did not. An arousal-by-saliency interaction in category-specific brain regions (fusiform face area for salient faces and parahippocampal place area for non-salient places) indicated that brain activation associated with processing the salient stimulus was enhanced under arousal whereas activation associated with processing the non-salient stimulus was suppressed under arousal. This is the first functional magnetic resonance imaging study to demonstrate that arousal can enhance information processing for prioritized stimuli while simultaneously impairing processing of non-prioritized stimuli. Thus, it goes beyond previous research to show that arousal does not uniformly enhance perceptual processing, but instead does so selectively in ways that optimizes attention to highly salient stimuli.

视觉工作记忆内容引导情绪面孔的视觉搜索

本文通过采用记忆任务和视觉搜索任务相结合的方式，以简笔画情绪面孔为材料，探讨了视觉工作记忆内容对情绪面孔视觉搜索的影响。结果发现：不同工作记忆内容条件下对情绪面孔搜索的反应时存在显著差异，对两种情绪面孔搜索的反应时在无效信息条件下显著慢于有效信息条件下。结果表明，工作记忆内容能够引导情绪面孔的视觉搜索,实验结果拓展了偏向竞争理论模型的适用范围。 With the combined memory task and visual search paradigm, this study aimed to discuss the influence of contents of visual working memory to visual search of emotional faces. The results showed that the effect of the contents of visual working memory was significant. And the RTs were significantly longer in the invalid condition than in the valid condition for not only happy face but also angry face. The results suggested that the information which was maintained in visual working memory could affect the visual search efficiency of emotional faces. The findings broaden biased competition model.

Biased competition between Lgr5 intestinal stem cells driven by oncogenic mutation induces clonal expansion

The concept of ‘field cancerization’ describes the clonal expansion of genetically altered, but morphologically normal cells that predisposes a tissue to cancer development. Here, we demonstrate that biased stem cell competition in the mouse small intestine can initiate the expansion of such clones. We quantitatively analyze how the activation of oncogenic K-ras in individual Lgr5+ stem cells accelerates their cell division rate and creates a biased drift towards crypt clonality. K-ras mutant crypts then clonally expand within the epithelium through enhanced crypt fission, which distributes the existing Paneth cell niche over the two new crypts. Thus, an unequal competition between wild-type and mutant intestinal stem cells initiates a biased drift that leads to the clonal expansion of crypts carrying oncogenic mutations.

A biased competition account of attention and memory in Alzheimer's disease.

The common view of Alzheimer's disease (AD) is that of an age-related memory disorder, i.e. declarative memory deficits are the first signs of the disease and associated with progressive brain changes in the medial temporal lobes and the default mode network. However, two findings challenge this view. First, new model-based tools of attention research have revealed that impaired selective attention accompanies memory deficits from early pre-dementia AD stages on. Second, very early distributed lesions of lateral parietal networks may cause these attention deficits by disrupting brain mechanisms underlying attentional biased competition. We suggest that memory and attention impairments might indicate disturbances of a common underlying neurocognitive mechanism. We propose a unifying account of impaired neural interactions within and across brain networks involved in attention and memory inspired by the biased competition principle. We specify this account at two levels of analysis: at the computational level, the selective competition of representations during both perception and memory is biased by AD-induced lesions; at the large-scale brain level, integration within and across intrinsic brain networks, which overlap in parietal and temporal lobes, is disrupted. This account integrates a large amount of previously unrelated findings of changed behaviour and brain networks and favours a brain mechanism-centred view on AD.

Selective visual processing across competition episodes: a theory of task-driven visual attention and working memory

The goal of this review is to introduce a theory of task-driven visual attention and working memory (TRAM). Based on a specific biased competition model, the ‘theory of visual attention’ (TVA) and its neural interpretation (NTVA), TRAM introduces the following assumption. First, selective visual processing over time is structured in competition episodes. Within an episode, that is, during its first two phases, a limited number of proto-objects are competitively encoded—modulated by the current task—in activation-based visual working memory (VWM). In processing phase 3, relevant VWM objects are transferred via a short-term consolidation into passive VWM. Second, each time attentional priorities change (e.g. after an eye movement), a new competition episode is initiated. Third, if a phase 3 VWM process (e.g. short-term consolidation) is not finished, whereas a new episode is called, a protective maintenance process allows its completion. After a VWM object change, its protective maintenance process is followed by an encapsulation of the VWM object causing attentional resource costs in trailing competition episodes. Viewed from this perspective, a new explanation of key findings of the attentional blink will be offered. Finally, a new suggestion will be made as to how VWM items might interact with visual search processes.

Art, Meaning, and Perception: A Question of Methods for a Cognitive Neuroscience of Art

Neuroscience of art might give us traction with aesthetic issues. However it can be seen to have trouble modeling the artistically salient semantic properties of artworks. So if meaning really matters, and it does, even in aesthetic contexts, the prospects for this nascent field are dim. The issue boils down to a question of whether or not we can get a grip on the kinds of constraints present and available to guide interpretive behavior in our engagement with works of fine art. I argue that biased competition models of selective attention can be used to solve this problem, generalize to the affective content of our responses to artworks, and so show that research in cognitive neuroscience is germane to the types of problems of interest within the philosophy of art.

Top-Down Beta Rhythms Support Selective Attention via Interlaminar Interaction: A Model

Cortical rhythms have been thought to play crucial roles in our cognitive abilities. Rhythmic activity in the beta frequency band, around 20 Hz, has been reported in recent studies that focused on neural correlates of attention, indicating that top-down beta rhythms, generated in higher cognitive areas and delivered to earlier sensory areas, can support attentional gain modulation. To elucidate functional roles of beta rhythms and underlying mechanisms, we built a computational model of sensory cortical areas. Our simulation results show that top-down beta rhythms can activate ascending synaptic projections from L5 to L4 and L2/3, responsible for biased competition in superficial layers. In the simulation, slow-inhibitory interneurons are shown to resonate to the 20 Hz input and modulate the activity in superficial layers in an attention-related manner. The predicted critical roles of these cells in attentional gain provide a potential mechanism by which cholinergic drive can support selective attention.

A model for selective visual attention predicts information routing

A remarkable feature of the brain is its ability to flexibly process information in a context-dependent manner. For example, selective attention allows to focus on relevant information, and to ignore distracting features of a visual scene. Here we develop a model to investigate a putative neural mechanism by which attention might dynamically change the functional configuration of networks in visual cortex. Since efferents from multiple neurons in an early visual area converge onto the same neuron in a higher area, synaptic input induced by an attended object should be more efficient in driving the post-synaptic neuron than an input induced by a simultaneously presented, but unattended object. In fact, it has been found that the firing rate of a post-synaptic neuron in such a situation is similar to its activity when the unattended stimulus is absent. However, if no attention is directed while two stimuli are present, the firing rate of the post-synaptic neuron is approximately at the mean of the rates at which it would fire if each of two stimuli were presented alone (biased competition [1,2]). Attention is thus assumed to selectively promote information transfer between visual areas. Recent experiments support this idea by showing that V4 local field potentials are correlated with a temporal modulation of the attended stimulus and not with the temporal modulation of a non-attended stimulus in the same receptive field (gating [3]). Several models were proposed to explain the effect of biased competition and information routing [4,5]. However, here we construct a biophysically plausible model that specifically reproduces both experimental results within the same framework. It comprises four populations of recurrently coupled networks of conductance-based spiking neurons with lateral inhibition. Upon activation, these populations engage in oscillatory activity. The first two networks correspond to a lower visual area with non-overlapping receptive fields, which both project to the third and the fourth network corresponding to higher area populations with larger receptive fields. We assume attention to manifest as an additional input to one lower area population. Deployment of attention consequently results in a bias of firing rates between the populations in the lower area. This bias induces a phase relation between the lower and the higher area that is more suitable for information transmission from the attended stimulus. We show that this mechanism is capable to explain both, the biased competition effect of the firing rate, and selective gating of information flow. We thus propose a combination of cortical network topology, neuronal population dynamics, and selective additional input as putative neural underpinnings of attention.

A Potential Event-Competition Bias in Safety Signal Detection: Results from a Spontaneous Reporting Research Database in France

In spontaneous reporting databases, reports of well-established drug-event associations may mask alerts that arise from other drugs (drug competition bias). However, a symmetrical event-competition bias has not yet been explored whereby known events may mask an association with new events for a given drug or drug class. The objective of this study was to explore the effects of event-competition bias on safety signals generated from spontaneous reporting databases. The drug classes tested included statins, oral anticoagulants, antipsychotics and HIV antiretrovirals. For each, a type A reaction was selected, and its potential competitive effect on the generation of other safety signals for the drug was explored. These were rhabdomyolysis/myopathy for statins, haemorrhage for oral anticoagulants, extrapyramidal syndrome for antipsychotics and lipodystrophy for HIV antiretrovirals. Signals of disproportionate reporting (SDRs) were detected using the case/non-case approach in the French research spontaneous reporting database (which contains reports from 1 January 1986 to 31 December 2001), before and after removing all reports concerning these competitor events. SDRs were considered as potential signals if not reported in the literature before 1 January 2002 but confirmed since. The whole database included 207,236 reports, 4,355 of which included statins as one of the suspected drugs. The removal of reports of rhabdomyolysis/myopathy concerned 8,425 reports among which 867 involved statins. After this removal, 11 new SDRs appeared for statins that had not been detected initially. Similarly, 15 SDRs were unmasked for oral anticoagulants, six for antipsychotics and nine for HIV antiretrovirals. After literature-based assessment, five of the 41 unmasked SDRs appeared related to potential safety signals confirmed after 2002. This study demonstrated that a masking phenomenon resulting from an event-competition effect could occur when performing signal detection using disproportionality analyses of spontaneous reporting databases. This should be taken into account when routine signal detection is performed.

“Whom Should I Pass To?” The More Options the More Attentional Guidance from Working Memory

Three experiments investigated the predictions of the biased competition theory of selective attention in a computer based sport task. According to this theory objects held in the circuitry of working memory (WM) automatically bias attention to objects in a visual scene that match or are related to the WM representation. Specifically, we investigated whether certain players that are activated in the circuitry of WM automatically draw attention and receive a competitive advantage in a computer based sport task. In all three experiments participants had to hold an image of a certain player in WM while engaged in a speeded sport task. In Experiment 1 participants had to identify as quickly as possible which player was in possession of the ball. In Experiment 2 and 3 participants had to decide to which player they would pass to in a cartoon team handball situation and a photo picture basketball situation. The results support the biased competition theory of selective attention and suggest that certain decision options receive a competitive advantage if they are associated with the activated contents in the circuitry of WM and that this effect is more pronounced when more decision options compete for attention. A further extension compared to previous research was that the contents of working memory not only biased attention but also actual decisions that can lead to passing errors in sport. We critically discuss the applied implications of the findings.

Mercadona (Spain): a retail model in expansion

Purpose – This paper evaluates the effect of Spain's regulatory framework on Mercadona's expansion. Mercadona is the main company in this commercial distribution sector and so we have taken the North American company Wal-Mart as a classic example of the sector on a world scale. In Spain the regulatory framework is characterized by the high grade of autonomy of the regional governments over the development of business regulation. In other words, the main objective is to check the extent of competitive bias resulting from regulatory risk. Design/methodology/approach – The article discusses the stores and retailers of Mercadona. Through the use of quantitative indicators the degree of concentration-dispersion is studied, which is reflected graphically with a series of maps. It also discusses the normalisation constraints by quantitative data analysis from a region with trade liberalisation criteria (Madrid) and another with criteria for restricting the construction of large retail outlets (Barcelona) Findings – In the commercial distribution sector, certain firms stand out due to their rapid expansion, firms that have been successful in implementing widely different business philosophies. This article interprets the course and the immediate challenges for Mercadona, taking Wal-Mart as a reference, since this company is already at a more advanced stage of development: the conversion of an operator on an international scale. Originality/value – The study described helps in understanding the process of forming a large commercial distribution chain in Southern Europe. This example in turn allows an understanding of business concentration processes in this sector.

Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories.

Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory.

A biased activation theory of the cognitive and attentional modulation of emotion.

Cognition can influence emotion by biasing neural activity in the first cortical region in which the reward value and subjective pleasantness of stimuli is made explicit in the representation, the orbitofrontal cortex (OFC). The same effect occurs in a second cortical tier for emotion, the anterior cingulate cortex (ACC). Similar effects are found for selective attention, to for example the pleasantness vs. the intensity of stimuli, which modulates representations of reward value and affect in the orbitofrontal and anterior cingulate cortices. The mechanisms for the effects of cognition and attention on emotion are top-down biased competition and top-down biased activation. Affective and mood states can in turn influence memory and perception, by backprojected biasing influences. Emotion-related decision systems operate to choose between gene-specified rewards such as taste, touch, and beauty. Reasoning processes capable of planning ahead with multiple steps held in working memory in the explicit system can allow the gene-specified rewards not to be selected, or to be deferred. The stochastic, noisy, dynamics of decision-making systems in the brain may influence whether decisions are made by the selfish-gene-specified reward emotion system, or by the cognitive reasoning system that explicitly calculates reward values that are in the interests of the individual, the phenotype.

Saccade preparation is required for exogenous attention but not endogenous attention or IOR.

Covert attention is tightly coupled with the control of eye movements, but there is controversy about how tight this coupling is. The premotor theory of attention proposes that activation of the eye movement system is necessary to produce shifts of attention. In this study, we experimentally prevented healthy participants from planning or executing eye movements and observed the effect on exogenous attention, inhibition of return (IOR), and endogenous attention. The participants experienced a deficit of exogenous attentional facilitation that was specific to locations that were inaccessible by saccade. In contrast, their ability to endogenously orient attention was preserved, as was IOR. These results show that (a) exogenous attention depends on motor preparation, (b) IOR is independent of motor preparation and exogenous attention, and (c) endogenous attention is independent of motor preparation. Although these data are consistent with a weak version of the premotor theory, we believe they can be better explained by a biased competition account of visual attention.

Biased competition in the global workspace: Comment on “Consciousness, crosstalk and the mereological fallacy: An evolutionary perspective” by R. Wallace

Biased competition in the global workspace: Comment on “Consciousness, crosstalk and the mereological fallacy: An evolutionary perspective” by R. Wallace