The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation

Abstract

Current understanding within the field of neuroscience regarding why the brain requires significant periods of sleep rests upon the existence of extremely stereotypical patterns of oscillatory neural activity found in almost all mammals. Within these characteristic patterns of wide-scale neural activity occurs crossregional synchronization of oscillations of various frequencies and this coupling is fundamental to the process of memory consolidation. Specifically, high-frequency oscillations, or ripples, in the hippocampal formation are required for the conversion of short-term to long-term memory. These ripples couple to two slower oscillations found in the cortex, delta waves and spindles. The author describes here his contributions to the field of memory consolidation showing that hippocampal ripples in aged rats are of decreased frequency during sleep but not during wake. In addition, it is well documented that with age, behavioral and neural sleep parameters decrease while the incidence of neurodegenerative diseases increases. The author will discuss unpublished findings of behavioral sleep disturbances and changes in cortical sleep oscillations preceding motor impairment in a LRRK2 mouse model of Parkinson’s disease (PD), and explore herein putative links between age-related changes in neural oscillations and the predilection towards neurodegeneration.