On the role of the ventral attention system in spatial orienting

We suggest that fMRI evidence is not sufficient to study orienting of attention, but complementary evidence from other techniques should be taken into account, especially when exploring the fast and short-lasting mechanisms of exogenous attentional orienting

L’adaptation prismatique en réalité virtuelle: un nouvel outil d’étude des effets d’adaptation et de réadaptation de l’héminégligence

L’adaptation prismatique (AP) consiste à induire une perturbation visuelle de l’environnement à l’aide de lunettes prismatiques qui décalent le champ visuel latéralement de quelques degrés. Cette méthode, très facile à mettre en œuvre et non invasive repose sur des mécanismes de plasticité cérébrale des fonctions sensori-motrices et est parfois utilisée en rééducation pour réduire le biais attentionnel de patients cérébro-lésés présentant des signes de négligence spatiale. Les signes de négligence ne semblent toutefois pas pouvoir s’améliorer chez tous les patients traités et plusieurs études ne retrouvent pas d’effets bénéfiques sur les manifestations cliniques de la négligence à long terme. Ces différences de résultats peuvent notamment être expliquées par la difficulté de conduire des études en double aveugle et donc d’exclure certains biais expérimentaux comme des effets placebo. Il est en effet difficile pour l’expérimentateur, du fait de la forme et du poids des lunettes prismatiques, de ne pas être informé du traitement appliqué. Pour répondre à ces limitations, notre groupe de recherche a récemment mis au point un protocole d’AP en réalité virtuelle immersive. Le biais d’adaptation est ici induit grâce au décalage visuel entre la position du contrôleur tenu dans la main des participants et sa représentation dans l’environnement visuel. Après une présentation du protocole d’AP classique et des principaux résultats observés dans le traitement de l’héminégligence, nous détaillerons comment l’AP peut être implémentée en réalité virtuelle immersive et quels sont les avantages et différences de cette technique par rapport au protocole d’AP classique

Ilex crenata Thunb. var. fukasawana Makino

原著和名: ツクシイヌツゲ科名: モチノキ科 = Aquifoliaceae採集地: 熊本県 球磨郡 山江村 (肥後 球磨郡 山江村)採集日: 1972/8/24採集者: 萩庭丈壽整理番号: JH025638国立科学博物館整理番号: TNS-VS-97563

Cross-modal integration during value-driven attentional capture

A growing body of evidence suggests that reward may be a powerful determinant of attentional selection. To date, the study of value-based attentional capture has been mainly focused on the visual sensory modality. It is yet unknown how reward information is communicated and integrated across the different senses in order to resolve between competing choices during selective attention. Our study investigated the interference produced by an auditory reward-associated distractor when a semantically-related visual target was concurrently presented. We measured both manual and saccadic response times towards a target image (drum or trumpet), while an irrelevant sound (congruent or incongruent instrument) was heard. Each sound was previously associated with either a high or a low reward. We found that manual responses were slowed by a high-reward auditory distractor when sound and image were semantically congruent. A similar effect was observed for saccadic responses, but only for participants aware of the past reward contingencies. Auditory events associated with reward value were thus capable of involuntarily capturing attention in the visual modality. This reward effect can mitigate cross-modal semantic integration and appears to be differentially modulated by awareness for saccadic vs. manual responses. Together, our results extend previous work on value-driven attentional biases in perception by showing that these may operate across sensory modalities and override cross-modal integration for semantically-related stimuli. This study sheds new light on the potential implication of brain regions underlying value-driven attention across sensory modalities

Value-driven attentional capture in neglect

OBJECTIVE: Recent studies suggest that motivational cues such as rewards may be a powerful determinant of attentional selection, both in healthy subjects and in brain-damaged patients suffering from neglect. However, the exact brain mechanisms underlying these effects and their relation to other well-known attentional systems are still poorly known. METHODS: We designed a visual search paradigm to examine how value-based attentional priority could modulate spatial orienting in patients with pathological biases due to neglect after right hemispheric stroke. Targets were preceded by exogenous valid or invalid spatial cues, in the presence or absence of distractors that were associated with high reward values subsequent to an initial reinforcement training phase. RESULTS: We found that the learned reward value of distractors interfered with spatial reorienting toward the left (neglected) side when neglect patients were invalidly cued to the right side. Moreover, the presence of reward-associated distractors in the contralesional field interfered most with the detection of task-relevant targets on the same side, and this interference was exaggerated with more severe neglect. Voxelwise anatomical lesion analysis indicated that damage to the right angular gyrus, as well as lateral occipital and inferior temporal areas of the right hemisphere, were associated with stronger value-driven attentional effects. CONCLUSIONS: Visual stimuli previously associated with rewards receive higher attentional priority during visual search despite pathological spatial biases due to neglect, and thus interfere with orienting to contralesional targets, presumably by competing with top-down mechanisms controlling exogenous spatial attention. Reward signals may bias neural activity evoked by visual stimuli, independent of conscious control, through a common priority map integrating several different attentional influences. These results do not only provide novel insights to link spatial orienting and motivational signals within current models of attention, but also open new perspectives that may usefully be exploited for neurological rehabilitation strategies in patients suffering from attentional deficits and neglect

How motivation and reward learning modulate selective attention

Motivational stimuli such as rewards elicit adaptive responses and influence various cognitive functions. Notably, increasing evidence suggests that stimuli with particular motivational values can strongly shape perception and attention. These effects resemble both selective top-down and stimulus-driven attentional orienting, as they depend on internal states but arise without conscious will, yet they seem to reflect attentional systems that are functionally and anatomically distinct from those classically associated with frontoparietal cortical networks in the brain. Recent research in human and nonhuman primates has begun to reveal how reward can bias attentional selection, and where within the cognitive system the signals providing attentional priority are generated. This review aims at describing the different mechanisms sustaining motivational attention, their impact on different behavioral tasks, and current knowledge concerning the neural networks governing the integration of motivational influences on attentional behavior

From Action to Cognition: Neural Reuse, Network Theory and the Emergence of Higher Cognitive Functions

The aim of this article is to discuss the logic and assumptions behind the concept of neural reuse, to explore its biological advantages and to discuss the implications for the cognition of a brain that reuses existing circuits and resources. We first address the requirements that must be fulfilled for neural reuse to be a biologically plausible mechanism. Neural reuse theories generally take a developmental approach and model the brain as a dynamic system composed of highly flexible neural networks. They often argue against domain-specificity and for a distributed, embodied representation of knowledge, which sets them apart from modular theories of mental processes. We provide an example of reuse by proposing how a phylogenetically more modern mental capacity (mental rotation) may appear through the reuse and recombination of existing resources from an older capacity (motor planning). We conclude by putting arguments into context regarding functional modularity, embodied representation, and the current ontology of mental processes