Caffeine helps restore memory function after sleep loss, NUS Medicine study shows
Published: 23 Mar 2026
Associate Professor Sajikumar Sreedharan and Dr Wong Lik-Wei in front of their electrophysiology setup, with hippocampal signals recorded from sleep-deprived laboratory models.
A late night. A foggy morning. A familiar face that suddenly feels less familiar.
We often dismiss sleep deprivation as simple fatigue. But new research from the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine) reveals something far more precise. Sleep loss disrupts specific memory circuits in the brain, and caffeine may be able to repair that damage.
In a study published in Neuropsychopharmacology, study lead Associate Professor Sreedharan Sajikumar and first author Dr Lik-Wei Wong, both from the Department of Physiology and Healthy Longevity Translational Research Programme at NUS Medicine, investigated the effects of sleep deprivation in the hippocampal CA2 region of the brain. The hippocampus plays an essential role in memory and learning processes, and its CA2 region contributes significantly to social memory formation. The CA2 area also receives signals linked to the regulation of the sleep and wake cycle.
In their laboratory studies, researchers induced five hours of sleep deprivation, and subsequently provided caffeine mixed into drinking water for unrestricted consumption for seven days. Caffeine is a known stimulant. At the molecular level, it blocks adenosine receptor signalling pathways that accumulate during wakefulness and dampen brain activity. Electrophysiological recordings were subsequently performed on hippocampus samples to measure synaptic plasticity, which refers to the brain’s ability to strengthen or weaken connections between nerve cells based on experience and learning.
The study findings revealed that sleep deprivation disrupted the maintenance of synaptic plasticity, weakening communication between neurons in the hippocampal CA2 region of the brain. A reduced capacity for synaptic strengthening in the brain was observed, alongside clear deficits in social recognition memory. Overall, sleep loss disrupted both neural function and behaviour in a targeted and circuit-specific manner.
However, the researchers discovered that taking caffeine prior to sleep deprivation led to a recovery of synaptic communication in the CA2 region and plasticity returned to normal levels. Specifically, social memory deficits were reversed and the effects of caffeine were pathway specific, selectively restoring the disrupted brain circuit rather than globally increasing neural activity. This meant the control group that was not sleep-deprived did not exhibit signs of overstimulation despite caffeine exposure.
“Sleep deprivation does not just make you tired. It selectively disrupts important memory circuits,” noted Dr Wong. “We found that caffeine can reverse these disruptions at both the molecular and behavioural levels. Its ability to do so suggests that caffeine’s benefits may extend beyond simply helping us stay awake.”
Assoc Prof Sajikumar said, “Our findings position the CA2 region as a critical hub linking sleep and social memory. This research enhances our understanding towards the biological mechanisms underlying sleep-related cognitive decline. This could inform future approaches to preserving cognitive performance.”
View the press release here.
