Attentional Effort - An empirical investigation of attentional capacity

Abstract

Cognitive psychology has in recent years had an increasing focus on how attention may reflects the degree of processing intensity, also known as attentional effort. The theoretical developments on attentional effort have followed two main trajectories; effort as momentary demands on the attentional system, or degree of appliance reflecting top-down processing. The momentary demands on the attentional system have been operationalized through pupillary dilations, and increasing attentional effort is measured as the increased dilation of the eye pupil. Attentional effort as top-down processing on the other hand, have been investigated through functional imaging. A broad empirical evidence suggests that top-down attentional control is expressed in a distinct neural network, conceptualized as the dorsal network. A recent developmet of theory have suggested that the underlying mechanism regulating both pupillary dilations, and the neural network responsible for attentional control, is mediated by the release of noradrenaline (NE) from the Locus Correulus (LC). This offers a potential bridge between the two different theoretical traditions, unifying them in a joint account of attentional effort. It has further been suggested that the pupillary dilations can be used to predict activity in these neural nodes responsible for attentional processing.This relationship has however never been directly investigated. The current study therefore asessed concurrent pupillometry and fMRI during a sustained visual attention-task where degree of load, and hence attentional effort, on the attentional system was directly manipulated. We investigated how pupillary dilations in combination with parametrical increase of load can be used to predict neural activity in the LC-NE system, as well as activity in the dorsal system. Results reveal that pupillary dilations, in combination of parametrical modulation of load, correctly predicts activity in the dorsal network, as well in the LC. The precent study concludes that pupillary dilations is a valid predictor of neural activity related to attentional effort.

Cognitive psychology has in recent years had an increasing focus on how attention may reflects the degree of processing intensity, also known as attentional effort. The theoretical developments on attentional effort have followed two main trajectories; effort as momentary demands on the attentional system, or degree of appliance reflecting top-down processing. The momentary demands on the attentional system have been operationalized through pupillary dilations, and increasing attentional effort is measured as the increased dilation of the eye pupil. Attentional effort as top-down processing on the other hand, have been investigated through functional imaging. A broad empirical evidence suggests that top-down attentional control is expressed in a distinct neural network, conceptualized as the dorsal network. A recent developmet of theory have suggested that the underlying mechanism regulating both pupillary dilations, and the neural network responsible for attentional control, is mediated by the release of noradrenaline (NE) from the Locus Correulus (LC). This offers a potential bridge between the two different theoretical traditions, unifying them in a joint account of attentional effort. It has further been suggested that the pupillary dilations can be used to predict activity in these neural nodes responsible for attentional processing.This relationship has however never been directly investigated. The current study therefore asessed concurrent pupillometry and fMRI during a sustained visual attention-task where degree of load, and hence attentional effort, on the attentional system was directly manipulated. We investigated how pupillary dilations in combination with parametrical increase of load can be used to predict neural activity in the LC-NE system, as well as activity in the dorsal system. Results reveal that pupillary dilations, in combination of parametrical modulation of load, correctly predicts activity in the dorsal network, as well in the LC. The precent study concludes that pupillary dilations is a valid predictor of neural activity related to attentional effort.