The Uniqueness of Human Vulnerability to Brain Aging in Great Ape Evolution

Abstract

AbstractAging is associated with stable decline in the brain’s gray matter. This spatially specific, morphological change in humans has also recently been shown in chimpanzees. The correspondence between species-specific cortical expansion and the degree of brain structure deterioration in aging remains poorly understood. Here, we present a data-driven, cross-species comparative framework and apply it to explore the relationship between gray matter alterations with age and cross-species cerebral expansion in chimpanzees and humans. In humans, we found a positive relationship between cerebral aging and cortical expansion, whereas, in chimpanzees no such relationship was found between aging and cortical expansion. The greater aging and expansion effects in higher-order cognitive regions like the orbito-frontal cortex were observed to be unique to humans. This resembles the last-in, first out hypothesis for neurodevelopment on the evolutionary scale and may suggest a biological cost for recent evolutionary developments of human faculties.