Mental Visualization in the Cerebellum: Rapid Non-motor Learning at Sub-Lobular and Causal Network Levels

MALDI mass spectrometry imaging discloses the decline of sulfoglycosphingolipid and glycerophosphoinositol species in the brain regions related to cognition in a mouse model of Alzheimer's disease

Aging and neurodegenerative disease are accompanied by lipid perturbations in the brain. Understanding the changes in the contents and functional activity of lipids remains a challenge not only because of the many areas in which lipids perform bioactivities but also because of the technical limitations in identifying lipids and their metabolites. In the present study, we aimed to evaluate how brain lipids are altered in Alzheimer's disease (AD)-like pathology by using mass spectrometry imaging (MSI). The spatial distributions and relative abundances of lipids in the brains were compared between APP/PS1 mice and their age-matched wild-type (WT) mice by matrix-assisted laser desorption ionization (MALDI) MSI assays. The comparisons were correlated with the analysis using a spectrophotometric method to determine the relative contents of sulfatides in different brain regions. Significant changes of brain lipids between APP/PS1 and WT mice were identified: eight sulfoglycosphingolipid species, namely, sulfatides/sulfated hexosyl ceramides (ShexCer) and two glycerophosphoinositol (GroPIn) species, PI 36:4 and PI 38:4. The declines in the spatial distributions of these ShexCer and GroPIn species in the APP/PS1 mice brains were associated with learning- and memory-related brain regions. Compared with young WT mice, aged WT mice showed significant decreases in the levels of these ShexCer and GroPIn species. Our results provide technical clues for assessing the impact of brain lipid metabolism on the senescent and neurodegenerative brain. The decline in sulfatides and GroPIns may be crucial markers during brain senescence and AD pathology. Appropriate lipid complementation might be important potentials as a therapeutic strategy for AD.

Engaging distributed cortical and cerebellar networks through motor execution, observation, and imagery

When we interact with the environment around us, we are sometimes active participants, making directed physical motor movements and other times only mentally engaging with our environment, taking in sensory information and internally planning our next move without directed physical movement. Traditionally, cortical motor regions and key subcortical structures such as the cerebellum have been tightly linked to motor initiation, coordination, and directed motor behavior. However, recent neuroimaging studies have noted the activation of the cerebellum and wider cortical networks specifically during various forms of motor processing, including the observations of actions and mental rehearsal of movements through motor imagery. This phenomenon of cognitive engagement of traditional motor networks raises the question of how these brain regions are involved in the initiation of movement without physical motor output. Here, we will review evidence for distributed brain network activation during motor execution, observation, and imagery in human neuroimaging studies as well as the potential for cerebellar involvement specifically in motor-related cognition. Converging evidence suggests that a common global brain network is involved in both movement execution and motor observation or imagery, with specific task-dependent shifts in these global activation patterns. We will further discuss underlying cross-species anatomical support for these cognitive motor-related functions as well as the role of cerebrocerebellar communication during action observation and motor imagery.

The landscape of aging

Aging is characterized by a progressive deterioration of physiological integrity, leading to impaired functional ability and ultimately increased susceptibility to death. It is a major risk factor for chronic human diseases, including cardiovascular disease, diabetes, neurological degeneration, and cancer. Therefore, the growing emphasis on "healthy aging" raises a series of important questions in life and social sciences. In recent years, there has been unprecedented progress in aging research, particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes. In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases, we review the descriptive, conceptual, and interventive aspects of the landscape of aging composed of a number of layers at the cellular, tissue, organ, organ system, and organismal levels.