Prior Novelty Invigorates Future Mesolimbic Target Detection.

UNLABELLED

The ability to adapt to a dynamic world relies on detecting, learning, and responding to environmental changes. The detection of novelty serves as a critical indicator of such changes, priming mechanisms to detect and respond to goal-relevant information. However, neural regions that support novelty detection (hippocampus) and goal-directed behavior (dopaminergic midbrain [VTA] and prefrontal cortex [PFC]) have yet to be described as a sequential process that unfolds over time. Using a forward-prediction functional magnetic resonance imaging (fMRI) model, we explored interactions between the hippocampus, VTA, and PFC in humans performing a novelty-imbued target-detection task. Hippocampal novelty activation predicted subsequent VTA target activation, enhancing readiness to detect goal-relevant information. Concurrently, goal-directed PFC activation modulated VTA target activation, refining focus on behaviorally significant cues. These circuits function both synergistically and independently, promoting subsequent hippocampal activity during target trials. This work provides new insights into how distributed circuits coordinate to optimize adaptive behavior.

SIGNIFICANCE STATEMENT

Surviving in dynamic environments requires coordinated neural mechanisms to detect, learn from, and respond to change. However, neural regions that support novelty detection and goal-oriented behavior have yet to be described as a sequential process that unfolds over time. Using a novel forward-prediction functional magnetic resonance imaging (fMRI) model, we show that hippocampal activation during novelty predicts VTA readiness to process goal-relevant information. Concurrently, goal-directed PFC activity modulates VTA responses, sharpening focus on behaviorally significant cues. Furthermore, these synergistic and independent circuits enhance hippocampal sensitivity for future adaptive responses, offering novel insights into integration of brain mechanisms critical for learning, motivation, and executive function. Biological Sciences, Neuroscience.