The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation

Abstract

Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation.

Keywords: attention; attentional blink; consciousness; visual search; working memory.

Figure 1.

The visual attentional workspace (VAW), and its connections with the global workspace (GW). (a) Schematic of connections between areas in the visual cortex, at different levels of representation, and areas FEF, BA45 and BA46 in lateral prefrontal cortex, and the pulvinar in the thalamus. Connections involving the FEF, LIP and the pulvinar, as well as GW areas in lateral prefrontal cortex, are depicted with thin lines. Note how area LIP is connected with areas in the two streams of visual cortex, and with prefrontal areas. The core VAW areas, LIP, FEF and the pulvinar, are labelled in black (red online). GW areas are labelled in black with dotted contours (yellow online). Intermediate level areas V4 and MT are labelled in light grey (green online) and higher level areas CIT, AIT and 7a in dark grey (purple online). Areas in between these, PIT and MST, are labelled in mid grey (blue online). Note the recurrent connectivity patterns between visual cortex areas at different levels with both FEF and the pulvinar, as well as the direct connections between higher-level visual areas and GW areas in prefrontal cortex. Note also the connections between FEF, LIP and the pulvinar with GW areas in prefrontal cortex. Finally, note the role of intermediate level areas, such as V4 and MT, in connecting to both pathways and to lower level areas such as V2 and V1. V4 and MT also connect with LIP, FEF and the pulvinar. Feedback connections to lower-level areas such as V2 and V1 are not shown in this panel (adapted from [100]). (b) Illustration of reciprocal connectivity patterns in lateral cerebral cortex involving areas LIP and FEF with area BA46 in dorsolateral prefrontal cortex and intermediate level areas, as well as with area IT for object recognition, in visual cortex. This panel also shows connections with lower level areas, in particular, with V1 (reproduced from [101]). (Online version in colour.)

Figure 2.

Processing stages in TAC. The associated levels of representation (accessibility) and ERP components appear on the left. Neural computations and processing steps at different stages appear on the right. Also shown are discrete processing steps of different durations (e.g. for attentional filtering, selection and maintenance; light blue online), ‘ramping’ evidence accumulation operations of different durations (light red online), sensory coding (green online) and phasic responses related to ignition (and ‘decision’) (yellow online). Note the sequences of neural operations and computations within and across stages. On the right, note also the implication of the visual attentional workspace (VAW), global workspace (GW) and working memory (WM), at different stages. (Online version in colour.)