Neural correlates of resilience to the effects of hippocampal atrophy on memory

Abstract

Introduction: Cognitive reserve can be defined as a property of the brain that enables an individual to sustain cognitive performance in spite of age-related neural changes. This study uses brain imaging to identify which cognitive reserve mechanisms protect against the detrimental effect of hippocampal atrophy on associative memory. Methods: The study included 108 older adults from the Quebec Consortium for the early identification of Alzheimer’s disease. They received a magnetic resonance imaging examination to measure memory-related activations and hippocampal volume. Participants also completed a reserve-proxy questionnaire, and received a comprehensive clinical assessment. Results: Higher scores on the reserve questionnaire were associated with more activation in the right inferior temporal and left occipital fusiform gyri. The activation of the right temporal gyrus moderated the relationship between the volume of the hippocampus and face-name memory. A smaller volume was associated with weaker memory in participants with lower activation, but not in those with greater activation. Discussion: Recruitment of the temporal lobe protects against the detrimental effect of hippocampal atrophy on associative memory and contributes to cognitive reserve.

Keywords

• Cognitive reserve
• Aging
• Subjective cognitive decline
• Mild cognitive impairment
• Hippocampal atrophy
• Associative memory