Recovery sleep after total sleep deprivation preserves neutral and enhances emotional declarative memory

While recovery sleep can ameliorate the negative impacts of total sleep deprivation (TSD) on cognitive functioning, the effects of post-TSD sleep on different forms of emotional functioning remain unknown. Here, we investigated the effects of TSD and post-TSD recovery sleep on emotional memory processing.

Participants viewed scenes with negative or neutral central objects overlain on neutral backgrounds. The scene components were then presented separately for recognition testing. Participants in the TSD (n = 46) and Sleep (n = 22) conditions encoded the scenes the morning after the sleep manipulation (~10:00) and recognition memory was tested for half of the scene components after a short delay (Recog_1, ~10:45). Twenty of the TSD participants then received a 90-min nap opportunity (TSD_Nap). All participants then completed a second recognition test on the remaining images (Recog_2, ~14:00).

At Recog_1, all TSD participants showed worse overall memory compared to sleep participants. Specifically, memory was significantly worse for every scene component except neutral objects during Recog_1. At Recog_2, while memory deteriorated further for all scene components in the TSD_NoNap group, the TSD_Nap group showed no memory decline and had improved memory for negative objects, matching the sleep group at Recog_2.

Post-TSD recovery sleep preserves and restores memory functioning to the level seen in typically rested individuals. But extending TSD leads to continued memory deterioration, highlighting the importance of sleep in healthy emotional memory functioning. This paper is part of the Festschrift in honor of Dr. Robert Stickgold.