TY - JOUR AU - Stolp, Laura AU - Mandke, Kanad N AU - Mediano, Pedro Am AU - Gellersen, Helena M AU - Swartz, Alex AU - Rudzka, Katarzyna AU - Simons, Jon AU - Bekinschtein, Tristan A AU - Bor, Daniel TI - Informational complexity as a neural marker of cognitive reserve. JO - Brain and cognition VL - 193 SN - 0278-2626 CY - Amsterdam [u.a.] PB - Elsevier M1 - DZNE-2026-00197 SP - 106392 PY - 2026 AB - In Alzheimer's disease (AD), a mismatch between neurological damage and cognitive functioning often is attributed to individual differences in cognitive reserve. Understanding the neural mechanisms of cognitive reserve, which may differ across individuals, could help to assess the therapeutic effectiveness of interventions in AD. Here, 38 elderly participants performed a sustained attention task during high-density EEG while alert and drowsy. We defined cognitive reserve operationally as the ability to maintain task performance under drowsiness, with less impairment indicating higher reserve. Investigating performance variations during the active management of neural challenges offers a novel approach to studying cognitive reserve, capturing dynamics that mirror everyday cognitive demand. We relate performance under neural strain to various measures, including informational complexity using the Lempel-Ziv (LZsum) algorithm. We found a significant interaction between arousal and performance: LZsum values increased in high performers when drowsy but decreased in low performers. This effect was most pronounced in the frontal and central areas. These findings suggest LZsum reflects a compensatory mechanism and has potential as a neural marker of cognitive reserve. Additional structural MRI and network analyses revealed performance-related associations in entorhinal cortex, supramarginal gyrus, and frontoparietal networks, suggesting broader neural correlates of compensatory capacity. KW - Humans KW - Cognitive Reserve: physiology KW - Male KW - Female KW - Aged KW - Electroencephalography KW - Attention: physiology KW - Magnetic Resonance Imaging KW - Aged, 80 and over KW - Brain: physiology KW - Brain: diagnostic imaging KW - Alzheimer’s Disease (Other) KW - Cognitive reserve (Other) KW - EEG Experiment (Other) KW - Informational complexity (Other) KW - Neural Marker (Other) LB - PUB:(DE-HGF)16 C6 - pmid:41494311 DO - DOI:10.1016/j.bandc.2025.106392 UR - https://pub.dzne.de/record/285255 ER -