Physiology & behavior
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Physiology & behavior · Aug 2016
Sex-specific effects of daily exposure to sucrose on spatial memory performance in male and female rats, and implications for estrous cycle stage.
Excessive consumption of sugar sweetened drinks is proposed to produce functional changes in the hippocampus, leading to perturbations in learning and memory. In this study we examined the impact of 2h daily access to 10% sucrose (or no sucrose in controls) on recognition memory tasks in young male and female rats. In Experiment 1 we tested rats on memory tasks reliant on the hippocampus (place recognition), perirhinal cortex (object recognition), and a combination of hippocampus, prefrontal cortex and perirhinal cortex (object-in-place memory). ⋯ In Experiment 2 we tested place recognition and object-in-place memory in 10% sucrose exposed or non-exposed control female rats both during the metestrus (low estrogen) and proestrus (high estrogen) phases of their cycle on place recognition and object-in-place memory. Both sucrose exposed and control female rats were able to perform place object-in-place recognition correctly during metestrus and proestrus, however sucrose exposed rats were only able to perform place recognition correctly during proestrus. This indicates that when hippocampal function is compromised, endogenous estrogens may boost memory performance in females, and that males may be at more risk of high sugar diet induced cognitive deficits.
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Physiology & behavior · Aug 2016
Review Historical Article2015 Distinguished career award: Reflections on a career in science.
I was very pleased to receive the 2015 Distinguished Career Award from SSIB. This brief manuscript contains reminisces that might stir up pleasant memories in the older members of SSIB and also some general thoughts that I hope will be of value to the younger investigators who are closer to the beginning of their scientific careers. ⋯ They include Neal Miller, my doctoral mentor at Yale; Joe Holmes and Alan Epstein, my postdoctoral mentors; George Wolf and Reed Hainsworth, graduate student colleagues; John Brobeck, Paul Rozin, and Phil Teitelbaum, Michael Zigmond, Joe Verbalis, Jim Smith, and Alan Sved, faculty colleagues; Derek Denton, Paul McHugh, and James Fitzsimons, scientific role models; John Bruno, Steve Fluharty, and Linda Rinaman, post-doctoral trainees at Pitt; and Lori Flanagan, Kath Curtis, Michael Bushey, Mike Bykowski, Reza Manesh, Carrie Smith, Jennifer Vaughan, and Myriam Stricker, student trainees at Pitt. I thank them all and also my colleagues in SSIB not only for the honor of this award but for providing an abundant supply of insights and discoveries that have stimulated me throughout my adult life, in addition to being an attentive community in supporting my own work.
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Physiology & behavior · Jul 2016
Randomized Controlled TrialThe effects of caffeine ingestion on exercise-induced hypoalgesia: A pilot study.
Exercise acutely reduces pain sensitivity, termed exercise-induced hypoalgesia (EIH). The mechanisms underlying EIH remain unclear. Caffeine, a non-specific adenosine receptor antagonist has been shown to attenuate EIH in animals-suggesting the involvement of the adenosinergic system. ⋯ TPT increased from 46.2±2.9°C to 46.8±2.6°C (p=0.008) following the 15min exercise bout, but did not change (46.4±3.6°C vs. 46.8±3.3°C; p=0.24) following the shorter, higher intensity exercise bout. The results from this study indicate cycling exercise reduces pain sensitivity, especially to pressure stimuli. Caffeine ingestion did not alter the EIH response-suggesting adenosine may not play a prominent role in the EIH response in humans.
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Physiology & behavior · Apr 2016
Time-dependent behavioral, neurochemical, and metabolic dysregulation in female C57BL/6 mice caused by chronic high-fat diet intake.
High-fat diet (HFD) induced obesity is associated not only with metabolic dysregulation, e.g., impaired glucose homeostasis and insulin sensitivity, but also with neurological dysfunction manifested with aberrant behavior and/or neurotransmitter imbalance. Most studies have examined HFD's effects predominantly in male subjects, either in the periphery or on the brain, in isolation and after a finite feeding period. In this study, we evaluated the time-course of selected metabolic, behavioral, and neurochemical effects of HFD intake in parallel and at multiple time points in female (C57BL/6) mice. ⋯ Behaviorally, prolonged intake of HFD caused mice to be hypoactive and bury fewer marbles in a marble burying task; the latter was associated with significantly impaired hippocampal serotonin homeostasis. Cognitive (short-term recognition memory) function of mice was unaffected by chronic HFD feeding. Considering our prior findings of short-term (5-6 weeks) HFD-induced central (hyperactivity/anxiety and altered ventral hippocampal neurochemistry) effects and our current results, it seems that in female mice some metabolic/inflammatory dysregulations caused by HFD, such as gut permeability, appear early and persist, whereas others, such as glucose intolerance, are exaggerated with continuous HFD feeding; behaviorally, prolonged HFD consumption mainly affects locomotor activity and anxiety-like responses, likely due to the advanced obesity phenotype; neurochemically, the serotonergic system appears to be most sensitive to continued HFD feeding.
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Physiology & behavior · Apr 2016
Cognitive function at rest and during exercise following breakfast omission.
It has been suggested that breakfast omission, as opposed to breakfast consumption, has the detrimental effects on cognitive function. However, the effects of acute exercise following breakfast omission on cognitive function are poorly understood, particularly during exercise. The purpose of this study was to examine the interactive effects of breakfast and exercise on cognitive function. ⋯ Exercise and breakfast did not affect the accuracy of the Spatial DR task. The present results indicate that breakfast omission impairs executive function, but acute exercise improved executive function even after breakfast omission. It appears that beneficial effects of acute exercise on cognitive function are intact following breakfast omission.