The role of the locus coeruleus in mediating the attentional blink: A neurocomputational theory.

The attentional blink refers to the transient impairment in perceiving the 2nd of 2 targets presented in close temporal proximity. In this article, the authors propose a neurobiological mechanism for this effect. The authors extend a recently developed computational model of the potentiating influence of the locus coeruleus-norepinephrine system on information processing and hypothesize that a refractoriness in the function of this system may account for the attentional blink. The model accurately simulates the time course of the attentional blink, including Lag 1 sparing. The theory also offers an account of the close relationship of the attentional blink to the electrophysiological P3 component. The authors report results from two behavioral experiments that support a critical prediction of their theory regarding the time course of Lag 1 sparing. Finally, the relationship between the authors' neurocomputational theory and existing cognitive theories of the attentional blink is discussed. Copyright 2005 by the American Psychological Association

Pupil dilation reveals top–down attentional load during spatial monitoring

It has long been known that the diameter of human pupil enlarges with increasing effort during the execution of a task. This has been observed not only for purely mechanical effort but also for mental effort, as for example the computation of arithmetic problems with different levels of difficulty. Here we show that pupil dilation reflects changes in visuospatial awareness induced by attentional load during multi-tasking. In the single-task condition, participants had to report the position of lateralized, briefly presented, masked visual targets ("right", "left", or "both" sides). In the multitasking conditions, participants also performed additional tasks, either visual or auditory, to increase the attentional load. Sensory stimulation was kept constant across all conditions to rule out the influence of low-level factors. Results show that event-related pupil dilation strikingly increased with task demands, mirroring a concurrent decrease in visuospatial awareness. Importantly, pupil dilation significantly differed between two dual-task conditions that required to process the same number of stimuli but yielded differed levels of accuracy (difficulty). In contrast, pupil dilation did not differ between two conditions which were equally challenging but differed both in the modality of the dual task (auditory vs. visual) and in the number of stimuli to be attended. We conclude that pupil dilation genuinely reflects the top-down allocation of supramodal attentional resources

Age differences in gain- and loss-motivated attention

Adaptive gain theory (Aston-Jones & Cohen, 2005) suggests that the phasic release of norepinephrine (NE) to cortical areas reflects changes in the utility of ongoing tasks. In the context of aging, this theory raises interesting questions, given that the motivations of older adults differ from those of younger adults. According to socioemotional selectivity theory (Carstensen, Isaacowitz, & Charles, 1999), aging is associated with greater emphasis on emotion-regulation goals, leading older adults to prioritize positive over negative information. This suggests that the phasic release of NE in response to threatening stimuli may be diminished in older adults. In the present study, younger adults (aged 18–34 years) and older adults (60–82 years) completed the Attention Network Test (ANT), modified to include an incentive manipulation. A behavioral index of attentional alerting served as a marker of phasic arousal. For younger adults, this marker correlated with the effect of both gain and loss incentives on performance. For older adults, in contrast, the correlation between phasic arousal and incentive sensitivity held for gain incentives only. These findings suggest that the enlistment of phasic NE activity may be specific to approach-oriented motivation in older adults

A systems-level perspective on attention and cognitive control: Guided activation, adaptive gating, conflict monitoring, and exploitation vs. exploration, chapter 6

An understanding of attention is arguably one of the most important goals of the cognitive sciences and yet also has proven to be one of the most elusive. Most attention researchers will agree that a major problem has been agreeing on a definition of the term and the scope of the phenomena to which it applies. There are no doubt as many explanations for this state of affairs as there are those who consider themselves “attention researchers. ” However, most will probably agree that, in large measure, this is because attention is not a unitary phenomenon—at least not in the sense that it reflects the operation of a single mechanism, or a single function of one or a set of mechanisms. Rather, attention is the emergent property of the cognitive system that allows it to successfully process some sources of information to the exclusion of others, in the service of achieving some goals to the exclusion of others. This begs an important question: If attention is so varied a phenomenon, how can we make progress in understanding it? There are two simple answers to this question: Be precise about the specific (aspects of the) phenomena to be studied, and be precise about the mechanisms thought to explain them. In this chapter, we address a particular type of attentional phenomenon—that associate

A Reciprocal Relationship Between Bottom-up Trace Strength and the Attentional Blink Bottleneck: Relating the LC-NE and ST2 Models

There is considerable current interest in neural modelling of the attentional blink phenomenon. Two prominent models of this task are the Simultaneous Type Serial Token (ST2) model and the Locus Coeruleus Norepinephrine (LC-NE) model. The former of these generates a broad spectrum of behavioural data, while the latter provides a neurophysiologically detailed account. This paper explores the relationship between these two approaches. Specifically, we consider the spectrum of empirical phenomena that the two models generate, particularly emphasizing the need to generate a reciprocal relationship between bottom-up trace strength and the blink bottleneck. Then we discuss the implications of using ST2 token mechanisms in the LC-NE setting