How the Brain Selects Between Perception and Memory

Summary: The brain constantly toggles between focusing on external sensory information and internal mental representations like memories, plans, and thoughts. This seamless switching is crucial for adaptive behavior, yet the underlying mechanisms remain poorly understood. Recent research highlights both shared and distinct neural networks for external and internal attention, revealing costs and trade-offs when shifting between them. Understanding these processes could illuminate how attention operates in natural settings and how disruptions may contribute to cognitive or psychiatric disorders. Key Facts: Shared Networks: Both external and internal attention recruit overlapping frontoparietal networks, but internal attention also engages medial and ventrolateral prefrontal regions. Switching Costs: Behavioral studies show measurable performance costs when shifting attention between external and internal domains compared to within a single domain. Open Questions: It remains unclear whether a superordinate control system coordinates these shifts or if they emerge from competitive dynamics within existing attention systems.