Embedding reward signals into perception and cognition

Abstract

Despite considerable interest in the neural basis of valuation, the question of how valuation affects cognitive processing has received relatively less attention. Here, we review evidence from recent behavioral and neuroimaging studies supporting the notion that motivation can enhance perceptual and executive control processes to achieve more efficient goal-directed behavior. Specifically, in the context of cognitive tasks offering monetary gains, improved behavioral performance has been repeatedly observed in conjunction with elevated neural activations in task-relevant perceptual, cognitive and reward-related regions. We address the neural basis of motivation-cognition interactions by suggesting various modes of communication between relevant neural networks: (1) global hub regions may integrate information from multiple inputs providing a communicative link between specialized networks; (2) point-to-point interactions allow for more specific cross-network communication; and (3) diffuse neuromodulatory systems can relay motivational signals to cortex and enhance signal processing. Together, these modes of communication allow information regarding motivational significance to reach relevant brain regions and shape behavior.

Keywords: attention; executive function; fronto-parietal; motivation; posterior cingulate cortex.

Figure 1

Behavioral and neural effects of incentive motivation. (A) In all experiments, the detection sensitivity measure dprime (dp) increased as a function of absolute incentive magnitude. Red line: experiment 1 of Engelmann and Pessoa (2007); light orange line: experiment 2 of Engelmann and Pessoa (2007); dark red line: behavioral results of Engelmann et al. (2009). Parallel increases in evoked brain responses observed in the study by Engelmann et al. (2009) during the cue (B) and target (C) task phases in three types of regions, namely attentional, visual and reward-related (see Figure 2 for some of the sites). Results were obtained by pooling the responses from regions within these three networks. Net = network.

Figure 2

Brain regions exhibiting correlations with absolute incentive magnitude during the cue and target task periods. Some of the attentional (blue font), visual (light green), and valuation (orange) regions are illustrated. ACC, anterior cingulate cortex; FEF, frontal eye field; IPS, intraparietal sulcus; pre-SMA, pre-supplementary motor area; and preSMA, pre-supplementary motor area.

Figure 3

Mechanisms of motivational effects on attention. (A–C) Potential, abstract relationships between attention and motivation and their effects on behavior. (D) Modes of communication between cognitive and motivation networks illustrated for attentional-motivational interactions. (1) Interactions rely on “hub” regions, such as the anterior cingulate cortex, which are part of both attentional and motivational networks (indicated via the red outline in both the valuation-cortical and attentional networks). (2) In addition, specific regions may link the two networks, either directly or via the thalamus. (3) Finally, motivational signals are embedded within cognitive mechanisms via the action of diffuse neuromodulatory systems.