Yoga, a physical and contemplative practice, offers the practitioner a unique mind-body exercise experience demonstrating preliminary efficacy in improving cognitive health. We examine the evidence for underlying mechanisms that explain the yoga-cognition relationship in healthy older adults. The cognitive benefits of yoga may be the result of improved stress regulation and neurocognitive resource efficiency that facilitate bidirectional brain-body communication.

Background Multiple sclerosis (MS) can cause retinal thinning among persons with MS with optic neuritis (MS-ON). Macular xanthophylls are carotenoids that comprise the macular pigment, filtering blue light and countering photo-oxidation. However, macular xanthophyll status and its implications for markers of neuroaxonal degeneration have not been examined in MS. Objectives This study characterized differences in macular and serum xanthophylls, and retinal morphometry [retinal nerve fiber layer thickness at the macular (mRNFL) and optic disc (odRNFL) and total macular volume (TMV)] in individuals with MS and healthy controls (HC). Associations between macular pigment optical density (MPOD) and retinal morphometry were also examined. Methods Adults aged 45–64 y (HC, n = 42; MS, n = 40) participated in a cross-sectional study. MPOD was measured via heterochromatic flicker photometry. Retinal morphometry was measured via optical coherence tomography (OCT). Serum carotenoids were quantified using HPLC. Dietary carotenoids were collected using 7-d records. One-factor ANOVA was conducted to determine group effects on macular, serum, and dietary carotenoids. Partial correlations examined the relations between MPOD, retinal morphometry, diet, and serum carotenoids. Results Relative to HC, persons with MS-ON had lower MPOD (Cohen's d = 0.84, P = 0.014), lower odRNFL (Cohen's d = 2.16, P <0.001), lower mRNFL (Cohen's d = 0.57, P = 0.028), and lower TMV (Cohen's d = 0.95, P = 0.011). MS without ON (MS) had lower odRNFL (Cohen's d = 0.93, P = 0.001) than HC and lower serum lutein than MS-ON subjects (Cohen's d = 0.65, P = 0.014). Among MS, MPOD was positively correlated with odRNFL thickness (ρ = 0.43, P = 0.049) and TMV (ρ = 0.45, P = 0.039), whereas odRNFL was negatively correlated with serum lutein (ρ = −0.68, P = 0.016) and zeaxanthin (ρ = –0.62, P = 0.028). Conclusions Persons with MS-ON exhibited poorer xanthophyll status in the macula and serum. MPOD was associated with beneficial anatomical features in the MS group. These findings warrant confirmation with larger cohorts and prospective trials to evaluate xanthophyll effects on the anterior visual pathway in MS.

Objectives Individuals with multiple sclerosis (MS) often suffer a progressive loss in visual and cognitive function. While the exact reason for the cognitive decline in MS is unknown, generalized neurodegeneration of the central nervous system has been associated with lower carotenoid levels. Carotenoids have antioxidant effects that could support nerve health and be protective against cognitive decline. Carotenoids are also found in high concentration within the center of the retina, or macula. Their role in the brain may be related to their role in the eye and vision health. We investigated the correlation among macular carotenoids, retinal and nerve fiber layer thickness, and cognitive function in patients with MS. Methods Subjects included persons diagnosed with MS between 45–64 years (N = 29) living in Illinois. Carotenoid accumulation, defined as macular pigment optical density (MPOD), was measured using heterochromatic flicker photometry. Optical coherence tomography (Heidelberg Engineering, Germany) was used to assess total macular volume (TMV), central foveal (CF), and retinal nerve fiber layer thickness (RNFL). Cognitive function was assessed using an Eriksen flanker task for attentional control with event-related brain potentials. Results While MPOD was not correlated with TMV (Rho = 0.23, P = 0.14), CF (Rho < −0.01, P = 0.50), or RNFL (Rho = 0.19, P = 0.19), MPOD was correlated with faster congruent (Rho = −0.34, P = 0.04) and incongruent reaction time (Rho = −0.33, P = 0.04) and faster congruent (Rho = −0.52, P < 0.01) and incongruent (Rho = −0.37, P = 0.04) P2 latency. RNFL was positively correlated with incongruent accuracy (Rho = 0.41, P = 0.02) and inversely related to incongruent P2 latency (Rho = −0.41, P = 0.05), N2 congruent (Rho = −0.46, P = 0.03), and incongruent (Rho = −0.47, P = 0.03) amplitude. Additionally, RNFL was inversely related to congruent (Rho = −0.51, P = 0.02) and incongruent (Rho = −0.54, P = 0.01) P3 amplitude. Larger TMV was related to faster congruent (Rho = −0.43, P = 0.04) and incongruent P2 latency (Rho = −0.48, P = 0.02). CF was not correlated with any of the cognitive task outcomes. Conclusions Macular pigmentation and markers of retinal and optic nerve health may positively influence cognitive function in MS. However, MPOD and OCT measures were not correlated, suggesting that macular carotenoids, and retinal and optic nerve thickness may exert independent benefits for cognitive function. Funding Sources This work was funded by Pilot Research Grant from the National Multiple Sclerosis Society.

Although muscular strength has been linked to greater cognitive function across different cognitive domains, the mechanism(s) through which this occurs remain(s) poorly understood. Indeed, while an emerging body of literature suggests peripheral myokines released from muscular contractions may play a role in this relationship, additional research is needed to understand this link. Accordingly, this study sought to compare the influences of a particular myokine, Cathepsin B (CTSB), and muscular strength on hippocampal-dependent relational memory and cognitive control in 40 adults (age = 50.0±7.3 yrs). Overnight fasted venous blood draws were taken to assess plasma CTSB and muscular strength was assessed as maximal isokinetic strength testing using a Biodex dynamometer. Cognitive performance was assessed using a Spatial Reconstruction Task to assess relational memory and a modified Flanker task to assess cognitive control. Neuroelectric function for cognitive control was assessed using event-related potentials (ERPs) recorded during the Flanker task. Initial bivariate correlational analyses revealed that neither sex, age, lean body mass, or muscular strength was associated with CTSB. However, CTSB was inversely associated with reaction time and fractional peak latency of the P3 component of the Flanker task. Muscular strength was also inversely associated with reaction time and positively associated with relational memory performance. However, the influence of muscular strength on relational memory did not persist following adjustment for covariates. Greater circulating CTSB was selectively associated with greater cognitive control as well as faster information processing speed. These findings are the first to link circulating CTSB to both cognitive control and neuroelectric function. Future intervention studies are needed to examine the effects of changes in muscular strength, circulating myokines, and different domains of cognitive function.

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