Voluntary exercise can strengthen the circadian system in aged mice

Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2luc/C57BL/6) were studied at one of two ages: 3.5 months (n = 39) and >18 months (n = 72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n = 8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption

A behavioral economic supplement to brief motivational interventions for college drinking

Basic behavioral and neurobiological research has demonstrated that deficiencies in naturally occurring substance-free rewards are both a cause and a consequence of substance abuse that are due in part to the systematic discounting of delayed substance-free rewards. Existing brief motivational interventions (BMIs) for alcohol abuse do not target this mechanism of change. The goal of this uncontrolled pilot study was to evaluate a behavioral economic Substance-Free Activity Session (SFAS) to traditional alcohol BMIs. Participants were 13 college freshmen who reported two or more heavy drinking episodes (>5/4 drinks in an occasion for men/ women) in the past month. All participants completed a baseline assessment and a BMI that addressed alcohol use. In addition, participants received the SFAS, a 50-min individual session that attempts to increase engagement in constructive alternatives to drinking by enhancing the salience of delayed rewards (academic and career success) and the patterns of behavior (academic and extracurricular engagement) leading to these outcomes. At the 1-month follow-up assessment, participants reported significant reductions in heavy drinking, and moderate to large effect size reductions in weekly drinking and peak blood alcohol levels. The results of this pilot study provide preliminary support for the efficacy of this behavioral economic intervention session as a supplement to traditional alcohol BMIs