Which network of brain structures is associated with mind wandering and becomes active during rest?

The Default Mode Network (DMN) is indeed the correct choice when discussing the network of brain structures associated with mind wandering and activity during rest. The DMN is a network that includes regions such as the medial prefrontal cortex, posterior cingulate cortex, and lateral parietal cortex. This network is activated during periods of rest or when an individual is not focused on the external environment, allowing for introspection, daydreaming, and the processing of internal thoughts and memories.

During rest periods, the DMN becomes less engaged in active tasks and instead facilitates self-referential thought and spontaneous cognition. This is why it is specifically linked to mind wandering—a phenomenon characterized by the brain's drift away from the task at hand into thoughts that are not directly related to the immediate environment.

The other networks mentioned—such as the Executive Function Network, which is involved in decision-making and problem-solving, the Sensory Processing Network focusing on processing sensory information, and the Task-Positive Network, which is activated during specific tasks—do not share the same role in mind wandering and rest. Each of these networks is more relevant to focused cognitive tasks and active engagement with the environment as opposed to the introspective activities associated with the DMN.