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Photoperiod cognition

Alessandra Porcu, Malini Riddle, Davide Dulcis, David K Welsh
Seasonal changes in light exposure have profound effects on behavioral and physiological functions in many species, including effects on mood and cognitive function in humans. The mammalian brain's master circadian clock, the suprachiasmatic nucleus (SCN), transmits information about external light conditions to other brain regions, including some implicated in mood and cognition. Although the detailed mechanisms are not yet known, the SCN undergoes highly plastic changes at the cellular and network levels under different light conditions...
2018: Neural Plasticity
Adriano Dellapolla, Ian Kloehn, Harshida Pancholi, Ben Callif, David Wertz, Kayla E Rohr, Matthew M Hurley, Kimberly M Baker, Samer Hattar, Marieke R Gilmartin, Jennifer A Evans
Light improves cognitive function in humans; however, the neurobiological mechanisms underlying positive effects of light remain unclear. One obstacle is that most rodent models have employed lighting conditions that cause cognitive deficits rather than improvements. Here we have developed a mouse model where light improves cognitive function, which provides insight into mechanisms underlying positive effects of light. To increase light exposure without eliminating daily rhythms, we exposed mice to either a standard photoperiod or a long day photoperiod...
June 20, 2017: Scientific Reports
Clive A Marks, Malcolm Clark, David Obendorf, Graham P Hall, Inês Soares, Filipe Pereira
There has been little evaluation of anecdotal sightings as a means to confirm new incursions of invasive species. This paper explores the potential for equivocal information communicated by the media to account for patterns of anecdotal reports. In 2001, it was widely reported that red foxes (Vulpes vulpes) had been deliberately released in the island state of Tasmania (Australia), although this claim was later revealed to be baseless. Regardless, by 2013 a total of 3153 anecdotal fox sightings had been reported by members of the public, which implied their distribution was wide...
December 2017: Conservation Biology: the Journal of the Society for Conservation Biology
Devraj Singh, Vinod Kumar
The avian circadian pacemaker system is comprised of independent clocks in the retina, pineal and hypothalamus, as shown by daily and circadian oscillations of core clock genes (Per2, Cry1, Bmal1 and Clock) in several birds including migratory blackheaded buntings (Emberiza melanocephala). This study investigated the extra-hypothalamic brain circadian clocks in blackheaded buntings, and measured Per2, Cry1, Cry2, Bmal1 and Clock mRNA expressions at 4h intervals over 24h beginning 1h after light-on in the left and right telencephalon, optic tectum and cerebellum, the brain regions involved in several physiological and cognitive functions...
April 2017: Journal of Photochemistry and Photobiology. B, Biology
Deetje Iggena, York Winter, Barbara Steiner
Frequent flyers and shift workers undergo circadian dysrhythmia with adverse impact on body and mind. The circadian rhythm disorder "jet lag" disturbs hippocampal neurogenesis and spatial cognition, which represent morphological and functional adult brain plasticity. This raises the question if pro-neurogenic stimuli might prevent those consequences. However, suitable measures to mitigate jet lag-induced adverse effects on brain plasticity have been neglected so far. Here, we used adult C57Bl6 mice to investigate the pro-neurogenic stimuli melatonin (8 mg/kg i...
May 2017: Journal of Pineal Research
Abigail K Barnes, Summer B Smith, Subimal Datta
Cognitive dysfunction in depression has recently been given more attention and legitimacy as a core symptom of the disorder. However, animal investigations of depression-related cognitive deficits have generally focused on emotional or spatial memory processing. Additionally, the relationship between the cognitive and affective disturbances that are present in depression remains obscure. Interestingly, sleep disruption is one aspect of depression that can be related both to cognition and affect, and may serve as a link between the two...
2017: PloS One
Stanislav V Rozov, Janneke C Zant, Kestutis Gurevicius, Tarja Porkka-Heiskanen, Pertti Panula
AIM: Under natural conditions diurnal rhythms of biological processes of the organism are synchronized with each other and to the environmental changes by means of the circadian system. Disturbances of the latter affect hormonal levels, sleep-wakefulness cycle and cognitive performance. To study mechanisms of such perturbations animal models subjected to artificial photoperiods are often used. The goal of current study was to understand the effects of circadian rhythm disruption, caused by a short light-dark cycle regime, on activity of the cerebral cortex in rodents...
2016: Frontiers in Behavioral Neuroscience
Jeremy C Borniger, Randy J Nelson
Winter and summer present vastly different challenges to animals living outside of the tropics. To survive and reproduce, individuals must anticipate seasonal environmental changes and adjust physiology and behavior accordingly. Photoperiod (day length) offers a relatively 'noise free' environmental signal that non-tropical animals use to tell the time of year, and whether winter is approaching or receding. In some cases, photoperiodic signals may be fine-tuned by other proximate cues such as food availability or temperature...
January 2017: Seminars in Cell & Developmental Biology
Audrey Maille, Neville Pillay, Carsten Schradin
Cognitive flexibility describes the reversible changes of cognition in response to environmental changes. Although various environmental factors such as temperature, photoperiod and rainfall change seasonally, seasonal variation in cognitive performance has been reported in merely a few birds and mammals. We assessed whether cognitive performance in a wild population of African striped mice Rhabdomys pumilio, from the Succulent Karoo semidesert of South Africa, differed between summer and winter. In order to measure cognitive performance, striped mice were trapped in the field, tested under laboratory conditions at our research station and returned to the field within 5 h...
November 2015: Animal Cognition
Michel A Paul, Ryan J Love, Andrea Hawton, Josephine Arendt
The seasonal extremes of photoperiod in high latitudes place particular strain on the human circadian system. Arctic residence has been associated with poor sleep in both summer and winter. The goal of the work reported here was to study the circadian rhythms of individuals living in the high Arctic by measuring sleep variables and the timing of melatonin production. Two research trials were conducted in the built environment of CFS Alert (82° 29' 58″ N). Participants wore motion logging devices (actigraphs), which measure ambient light as well as motion, for 1week to provide data on sleep quantity, quality and light exposure...
March 15, 2015: Physiology & Behavior
David F Sherry, Scott A MacDougall-Shackleton
The hippocampus plays an important role in cognitive processes, including memory and spatial orientation, in birds. The hippocampus undergoes seasonal change in food-storing birds and brood parasites, there are changes in the hippocampus during breeding, and further changes occur in some species in association with migration. In food-storing birds, seasonal change in the hippocampus occurs in fall and winter when the cognitively demanding behaviour of caching and retrieving food occurs. The timing of annual change in the hippocampus of food-storing birds is quite variable, however, and appears not to be under photoperiod control...
April 2015: Frontiers in Neuroendocrinology
Krisztina Kopcsó, András Láng
INTRODUCTION: In our study we investigated fear of the dark in adolescence and emerging adulthood. First, we define fear and anxiety, which constitute together fear of the dark. We present the cognitive and interactionist models of fear, individual differences that affect the formation and maintenance of fear and the developmental aspects of this topic. The aim of our study was to map the phenomenon in adolescence and emerging adulthood, with respect to gender and age differences, and individual factors that affect the genesis of fear of the dark...
2014: Psychiatria Hungarica: A Magyar Pszichiátriai Társaság Tudományos Folyóirata
Robert F Casper, Shadab Rahman
Shiftwork has been identified as a risk factor for various medical problems, such as cancer, heart disease, metabolic disturbances, depression, and anxiety disorders, and as reviewed this month, adverse reproductive function. Shiftwork misaligns physiological rhythms with respect to each other and to external environmental rhythms such as the 24-hour light/dark cycle. Light is the strongest time cue for entraining circadian rhythms in mammals, and aberrant light exposure patterns during shiftwork is one of the key factors that induce circadian misalignment...
August 2014: Fertility and Sterility
Mark Lucock, Zoë Yates, Charlotte Martin, Jeong-Hwa Choi, Lyndell Boyd, Sa Tang, Nenad Naumovski, John Furst, Paul Roach, Nina Jablonski, George Chaplin, Martin Veysey
BACKGROUND AND OBJECTIVES: Vitamin D and folate are highly UV sensitive, and critical for maintaining health throughout the lifecycle. This study examines whether solar irradiance during the first trimester of pregnancy influences vitamin D receptor (VDR) and nuclear folate gene variant occurrence, and whether affected genes influence late-life biochemical/clinical phenotypes. METHODOLOGY: 228 subjects were examined for periconceptional exposure to solar irradiance, variation in vitamin D/folate genes (polymerase chain reaction (PCR)), dietary intake (food frequency questionnaire (FFQ)) and important adult biochemical/clinical phenotypes...
January 2014: Evolution, Medicine, and Public Health
Nelson Vilches, Carlos Spichiger, Natalia Mendez, Lorena Abarzua-Catalan, Hugo A Galdames, David G Hazlerigg, Hans G Richter, Claudia Torres-Farfan
Epidemiological and experimental evidence correlates adverse intrauterine conditions with the onset of disease later in life. For a fetus to achieve a successful transition to extrauterine life, a myriad of temporally integrated humoral/biophysical signals must be accurately provided by the mother. We and others have shown the existence of daily rhythms in the fetus, with peripheral clocks being entrained by maternal cues, such as transplacental melatonin signaling. Among developing tissues, the fetal hippocampus is a key structure for learning and memory processing that may be anticipated as a sensitive target of gestational chronodisruption...
2014: PloS One
Andrew Thompson, Helen Jones, Warren Gregson, Greg Atkinson
PURPOSE: To examine the effects of a simulated dawn during the last 30 min of sleep on the subsequent dissipation of sleep inertia and changes in simulated work and physical performance. METHODS: Eight participants, who reported difficulty with morning waking, were administered in a random order to a control (C) and a dawn simulation (DS) trial (starting 30 min prior to waking). Subjective ratings of sleep quality and alertness were obtained alongside measures of cognitive performance (addition and reaction time tasks measured at 5, 30 and 75 min after waking at habitual workday times)...
May 2014: European Journal of Applied Physiology
Cathleen G Jones, Pamela B Yang, Victor T Wilcox, Keith D Burau, Nachum Dafny
The psychostimulants considered the gold standard in the treatment of attention deficit hyperactivity disorder, one of the most common childhood disorders, are also finding their way into the hands of healthy young adults as brain augmentation to improve cognitive performance. The possible long-term effects of psychostimulant exposure in adolescence are considered controversial, and thus, the objective of this study was to investigate whether the chronic exposure to the psychostimulant amphetamine affects the behavioral diurnal rhythm activity patterns of female adolescent Wistar-Kyoto (WKY) rat...
May 2014: Journal of Neural Transmission
Antonio Martinez-Nicolas, Juan Antonio Madrid, Maria Angeles Rol
Modern societies are characterized by a 24/7 lifestyle (LS) with no environmental differences between day and night, resulting in weak zeitgebers (weak day light, absence of darkness during night, constant environmental temperature, sedentary LS and frequent snacking), and as a consequence, in an impaired circadian system (CS) through a process known as chronodisruption. Both weak zeitgebers and CS impairment are related to human pathologies (certain cancers, metabolic syndrome and affective and cognitive disorders), but little is known about how to chronoenhance the CS...
April 2014: Chronobiology International
Rebecca M Calisi, Daniel P Knudsen, Jesse S Krause, John C Wingfield, Timothy Q Gentner
Changes in hormones can affect many types of learning in vertebrates. Adults experience fluctuations in a multitude of hormones over a temporal scale, from local, rapid action to more long-term, seasonal changes. Endocrine changes during development can affect behavioral outcomes in adulthood, but how learning is affected in adults by hormone fluctuations experienced during adulthood is less understood. Previous reports have implicated the sex steroid hormone estradiol (E2) in both male and female vertebrate cognitive functioning...
2013: PeerJ
Jean-Christophe Cassel, Anne Pereira de Vasconcelos, Michaël Loureiro, Thibault Cholvin, John C Dalrymple-Alford, Robert P Vertes
The reuniens and rhomboid nuclei, located in the ventral midline of the thalamus, have long been regarded as having non-specific effects on the cortex, while other evidence suggests that they influence behavior related to the photoperiod, hunger, stress or anxiety. We summarise the recent anatomical, electrophysiological and behavioral evidence that these nuclei also influence cognitive processes. The first part of this review describes the reciprocal connections of the reuniens and rhomboid nuclei with the medial prefrontal cortex and the hippocampus...
December 2013: Progress in Neurobiology
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