Attention and Consciousness: Two Distinct Brain Processes

Division of Biology 216-76, California Institute of Technology, Pasadena, CA 91125, USA.
Trends in Cognitive Sciences (Impact Factor: 21.97). 02/2007; 11(1):16-22. DOI: 10.1016/j.tics.2006.10.012
Source: PubMed


The close relationship between attention and consciousness has led many scholars to conflate these processes. This article summarizes psychophysical evidence, arguing that top-down attention and consciousness are distinct phenomena that need not occur together and that can be manipulated using distinct paradigms. Subjects can become conscious of an isolated object or the gist of a scene despite the near absence of top-down attention; conversely, subjects can attend to perceptually invisible objects. Furthermore, top-down attention and consciousness can have opposing effects. Such dissociations are easier to understand when the different functions of these two processes are considered. Untangling their tight relationship is necessary for the scientific elucidation of consciousness and its material substrate.

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Available from: Naotsugu Tsuchiya, Feb 18, 2014
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    • "Or alternately, does it refer to attention as a mechanism of consciousness in the sense that consciousness, once attained, is a prerequisite for deploying attention? There appear to be problems with both of these interpretations, since recent theoretical and empirical studies indicate that visual attention and consciousness do not share identical underlying neural processes (Brascamp, van Boxtel, Knapen, & Blake, 2009; Koch & Tsuchiya, 2007; Lamme, 2003; Tallon-Baudry, 2012; Tsuchiya & Koch, 2008; van Boxtel, Tsuchiya, & Koch, 2010a, 2010b; Woodman & Luck, 2003; Wyart & Tallon-Baudry, 2008; Wyart, Dehaene, & Tallon-Baudry, 2012). Results of these studies support the hypothesis of two partially overlapping yet partially independent entities, each of which is neither necessary nor sufficient for the other. "

    Consciousness and Cognition 09/2015; 35. DOI:10.1016/j.concog.2015.04.021 · 2.31 Impact Factor
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    • "Because of parietal areas' known role in attention, neglect is often thought a disorder of attention. But some commentators go beyond this, taking it also to be a disorder of consciousness, claiming that in hemispatial neglect there is no experience of leftlocated items (Driver & Vuilleumier 2001; Koch & Tsuchiya 2007; Prinz 2007; Vosgerau & Newen 2008). 21 For others, this is hasty: Perhaps when the neglect patient fails to acknowledge an object, there is an experience of the object, but an inability to access the experience prevents 20 Hemispatial neglect can also manifest as a failure to acknowledge the left part of individual objects, the coming two examples being instances of this. "
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    DESCRIPTION: Research into the neural correlates of consciousness (NCC) aims to identify not just those brain areas that are NCC, but also those that are not. In the received method for ruling out a brain area from being an NCC, this is accomplished by showing a brain area’s content to be consistently absent from subjects’ reports about what they are experiencing. This paper points out how this same absence can be used to infer that the brain area’s content is cognitively inaccessible, in which case we would expect its content to be absent from subjects’ reports whether its content is (phenomenally) conscious or not. If so, such reports cannot count as evidence against that brain area being an NCC, and the received method fails. An alternative method (one suggested in Block 2007) is considered.
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    • "At this stage, the visual stimulus is assumed to be processed preconsciously, because it is potentially accessible for conscious report as soon as it gains access to the global workspace through additional top-down attentional amplification . Note that in the neuronal global workspace model, attention is considered a necessary prerequisite for conscious visual perception (for different opinion, see Koch and Tsuchiya, 2007). Top-down amplification through (spatial and/or temporal) attention can be triggered either voluntarily or by automatic bottom-up attraction through stimulus salience (stimulus strength, sharp onset, or strong emotional content ) (Dehaene et al., 2006; Dehaene and Changeux, 2011). "
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    ABSTRACT: Neural correlates of consciousness (NCC) have been a topic of study for nearly two decades. In functional imaging studies, several regions have been proposed to constitute possible candidates for NCC, but as of yet, no quantitative summary of the literature on NCC has been done. The question whether single (striate or extrastriate) regions or a network consisting of extrastriate areas that project directly to fronto-parietal regions are necessary and sufficient neural correlates for visual consciousness is still highly debated [e.g., Rees, et al., 2002, Nat Rev. Neurosci 3, 261-270; Tong, 2003, Nat Rev. Neurosci 4, 219-229]. The aim of this work was to elucidate this issue and give a synopsis of the present state of the art by conducting systematic and quantitative meta-analyses across functional magnetic resonance imaging (fMRI) studies using several standard paradigms for conscious visual perception. In these paradigms, consciousness is operationalized via perceptual changes, while the visual stimulus remains invariant. An activation likelihood estimation (ALE) meta-analysis was performed, representing the best approach for voxel-wise meta-analyses to date. In addition to computing a meta-analysis across all paradigms, separate meta-analyses on bistable perception and masking paradigms were conducted to assess whether these paradigms show common or different NCC. For the overall meta-analysis, we found significant clusters of activation in inferior and middle occipital gyrus, fusiform gyrus, inferior temporal gyrus, caudate nucleus, insula, inferior, middle and superior frontal gyri, precuneus, as well as in inferior and superior parietal lobules. These results suggest a subcortical-extrastriate-fronto-parietal network rather than a single region that constitutes the necessary NCC. The results of our exploratory paradigm-specific meta-analyses suggest that this subcortical-extrastriate-fronto-parietal network might be differentially activated as a function of the paradigms used to probe for NCC. Copyright © 2015. Published by Elsevier Inc.
    NeuroImage 08/2015; 122. DOI:10.1016/j.neuroimage.2015.07.070 · 6.36 Impact Factor
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