Reward modulation of prefrontal and visual association cortex during an incentive working memory task

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Working memory (WM) performance is influenced by motivation, but neural mechanisms remain unclear.
• Top-down control is crucial for WM, involving enhancement of relevant and suppression of irrelevant stimuli.
• Previous fMRI studies identified visual association cortex activity correlating with attentional focus.

Purpose of the Study:

• To investigate the neural mechanisms by which reward motivation influences visual working memory (WM).
• To determine if reward levels modulate the enhancement and suppression of stimuli during WM encoding.
• To examine the role of prefrontal cortex and visual association areas in reward-modulated WM.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to monitor brain activity.
• Participants performed a delayed-recognition task assessing visual WM performance.
• Brain activity was analyzed for differences related to reward levels during stimulus encoding.

Main Results:

• Increased reward levels amplified neural enhancement and suppression effects in visual association cortex.
• Scene-selective and face-selective regions showed modulated activity with higher rewards.
• Prefrontal cortex exhibited enhanced activity during high-reward trials, suggesting top-down signaling.

Conclusions:

• Reward motivation significantly impacts WM performance by modulating neural activity.
• Top-down signaling from frontal regions enhances relevant stimuli and suppresses irrelevant ones in visual cortex.
• These findings elucidate the neural basis of how motivation drives cognitive control in WM.