The Modulatory Role of Reward on Attentional Brain Processes

Duke University, Durham NC

Investigators

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Abstract

ABSTRACT The ability to selectively focus attention on elements of our sensory environment is a critical cognitive func- tion that enables us to dynamically and flexibly enhance the processing of the most important stimuli, events, and tasks. Likewise, stimulus-reward associations and the potential for gaining reward on a task have also been found to enhance stimulus processing and influence behavior. There has been a growing recognition that these two core cognitive factors ? attention and reward ? interact extensively to shape cognition and behavior. In the next period of this grant, we propose a series of experiments investigating this vital interactive relation- ship between reward and attention. In particular, in Aim 1 we examine how cueing with advance information on locationally specific reward-magnitude potential and classic cueing of locational probability (Posner cueing) proactively shape attentional allocation and task performance. In contrast, in Aim 2 we examine how reward selectively associated with target-relevant stimuli or distractors in a visual-search attention task influences at- tentional and perceptual processes (Aim 2). We also expand our study of the interactive relationship between reward and attention to examine their interactions in audition, thereby also investigating the supramodality of these mechanisms (Aim 3). Lastly, we will also examine how stimulus-reward associations are updated in the sensory cortices by means of top-down modulatory mechanisms (Aim 4). An overarching working hypothesis in these studies is that a key way by which reward enhances task performance is by marshalling attentional control circuits that in turn allocate processing resources in the brain. We take a highly systems-oriented perspective in these studies: examining both (a) the attention- and re- ward-related cognitive-control mechanisms as they allocate and direct processing resources, and (b) markers of the modulations of those processing resources in the sensory cortices. As before, we will be taking a multi- methodological approach, using a combination of behavioral measures, event-related potentials (ERPs), event- related oscillatory EEG, and functional MRI (fMRI) to delineate the timing, sequence, and location of the under- lying neural processes and interregional neural interactions. Additionally, we will use simultaneous recordings of fMRI and EEG for several of the proposed experiments. Such an approach will enable us to perform trial-to- trial covariational analyses on the data patterns of these two measures of brain activity, providing powerful new ways to link the high-temporal-resolution EEG signals to the associated cortical generators measured in the fMRI. Moreover, the simultaneous recording will also allow us to examine how subcortical brain regions in- volved in attention and reward modulate the functional processes reflected by the cortical EEG ? reflecting crit- ical aspects of processing that cannot be assessed when these measures are acquired separately. Thus, these experiments will delineate with exceptional precision the neural mechanisms by which attentional and reward-related processes interact in the human brain and contribute to adaptive behavior in our complex world.