Relating value-driven attentional capture to striatal dopamine: A positron emission tomography study

Abstract

Reward learning gives rise to strong attentional biases. Stimuli previously associated with reward automatically capture visual attention regardless of intention. Nonspecific measures of brain activity have implicated the striatum in value-driven attention. However, the neurochemical mechanisms underlying the attentional priority of learned reward cues remain unexplored, largely due to limitations inherent to the neuroimaging techniques commonly used in the field of human cognitive neuroscience. Here, we investigated the contribution of dopamine to value-driven attention using positron emission tomography (PET) with [11C]raclopride. Participants first completed a training phase in which color-defined targets were associated with a monetary reward when correctly reported, and then completed an unrewarded test phase in which these same color stimuli served as task-irrelevant distractors during visual search for a shape-defined target. Value-driven attentional capture was measured as the slowing of response time on high-value distractor trials as in prior studies. We show that the magnitude of value-driven attentional capture is correlated across individuals with the magnitude of dopamine release linked to distractor processing within the right caudate and posterior putamen. Furthermore, the ability to suppress value-driven attentional capture was associated with the suppression of striatal dopamine in these same regions. Our findings provide direct evidence linking dopamine signaling within the dorsal striatum to the involuntary orienting of attention, and specifically to the attention-grabbing quality of learned reward cues. These findings also shed light on the neurochemical basis of individual susceptibility to value-driven attentional capture, and, more broadly, highlight the value and feasibility of using PET to relate changes in the release of a neurotransmitter to attentional and learning processes in humans.

Meeting abstract presented at VSS 2016