Light Rhythm Research Articles

Walking behavior in a circular arena modified by pulsed light stimulation in Drosophila melanogaster w1118 line

The Drosophila melanogaster white-eyed w1118 line serves as a parental stock, allowing genetic recombination of any gene of interest along with a readily recognizable marker. w1118 flies display behavioral susceptibility to environmental stimulation such as light. It is of great importance to characterize the behavioral performance of w1118 flies because this would provide a baseline from which the effect of the gene of interest could be differentiated. Little work has been performed to characterize the walking behavior in adult w1118 flies. Here we show that pulsed light stimulation increased the regularity of walking trajectories of w1118 flies in circular arenas. We statistically modeled the distribution of distances to center and extracted the walking structures of w1118 flies. Pulsed light stimulation redistributed the time proportions for individual walking structures. Specifically, pulsed light stimulation reduced the episodes of crossing over the central region of the arena. An addition of four genomic copies of mini-white, a common marker gene for eye color, mimicked the effect of pulsed light stimulation in reducing crossing in a circular arena. The reducing effect of mini-white was copy-number-dependent. These findings highlight the rhythmic light stimulation-evoked modifications of walking behavior in w1118 flies and an unexpected behavioral consequence of mini-white in transgenic flies carrying w1118 isogenic background.

Circadian clocks of both plants and pollinators influence flower seeking behavior of the pollinator hawkmoth Manduca sexta

Most plant-pollinator interactions occur during specific periods during the day. To facilitate these interactions, many flowers are known to display their attractive qualities, such as scent emission and petal opening, in a daily rhythmic fashion. However, less is known about how the internal timing mechanisms (the circadian clocks) of plants and animals influence their daily interactions. We examine the role of the circadian clock in modulating the interaction between Petunia and one of its pollinators, the hawkmoth Manduca sexta. We find that desynchronization of the Petunia circadian clock affects moth visitation preference for Petunia flowers. Similarly, moths with circadian time aligned to plants show stronger flower-foraging activities than moths that lack this alignment. Moth locomotor activity is circadian clock-regulated, although it is also strongly repressed by light. Moths show a time-dependent burst increase in flight activity during subjective night. In addition, moth antennal responsiveness to the floral scent compounds exhibits a 24-hour rhythm in both continuous light and dark conditions. This study highlights the importance of the circadian clocks in both plants and animals as a crucial factor in initiating specialized plant-pollinator relationships.

Development of Intermodule Interactions in Field 18 in Kittens Reared in Different Visual Environments: Orientation Modules

The primary visual cortex of mammals with well developed visual analyzers is characterized by functional modules whose postnatal development depends on a combination of internal genetic and external factors determined by the visual environment. Concordance in the operation of orientation columns in field 18 was studied with the aim of assessing the maturation of intermodular interactions in the visual cortex of kittens reared in conditions of rhythmic light stimulation at frequencies of 15 and 50 Hz (the RLS-15 and RLS-50 groups). Functional maps obtained by an optical mapping method using internal signals were used for correlation comparison of responses at different points of the cortex recorded in response to presentation of visual stimuli with different physical characteristics. The results were compared with those from control animals and kittens reared in complete darkness (the DARK group). Animals of the RLS-15 group showed significant decreases in the coefficient of correlation between the dynamics of the responses of neighboring orientation modules regardless of the distance between the modules concerned. Possible links between these impairments and the functions of interneuronal interactions in the visual cortex and the development of internal cortical rhythms are discussed.

Educational complex of light-colored modeling of urban environment

Mechanisms, methodological tools and structure of a training complex of light-colored modeling of the urban environment are developed in this paper. The following results of the practical work of students are presented: light composition and installation, media facades, lighting of building facades, city streets and embankment. As a result of modeling, the structure of the light form is determined. Light-transmitting materials and causing characteristic optical illusions, light-visual and light-dynamic effects (video-dynamics and photostatics), basic compositional techniques of light form are revealed. The main elements of the light installation are studied, including a light projection, an electronic device, interactivity and relationality of the installation, and the mechanical device which becomes a part of the installation composition. The meaning of modern media facade technology is the transformation of external building structures and their facades into a changing information cover, into a media content translator using LED technology. Light tectonics and the light rhythm of the plastics of the architectural object are built up through point and local illumination, modeling of the urban ensemble assumes the structural interaction of several light building models with special light-composition techniques. When modeling the social and pedestrian environment, the lighting parameters depend on the scale of the chosen space and are adapted taking into account the visual perception of the pedestrian, and the atmospheric effects of comfort and safety of the environment are achieved with the help of special light compositional techniques. With the aim of realizing the tasks of light modeling, a methodology has been created, including the mechanisms of models, variability and complementarity. The perspectives of light modeling in the context of structural elements of the city, neuropsychology, wireless and bioluminescence technologies are proposed. Conclusions are given on the environment-forming and transforming significance of artificial light and light technologies in the space of modern city. Light-colored modeling identity is expressed in methodical and figurative-artistic continuity in the use of techniques of light composition and optical art. The use of light composition contributes to the expression of local identity by means and techniques of light composition in the context of the image, “genius loci” using the example of the Vladivostok seaside city. Identity in psychology is expressed in the personal selection of the techniques of light composition, which are used in light-colored modeling.

Functional connectivity of suprachiasmatic nucleus in major depressive episodes patients with morning heavy night light rhythm

Objective To explore the variations of functional connectivity in depressive episode patients with diurnal rhythm. Methods Totaly 44 patients with depressive episode with diurnal rhythm(rhythm group), 58 patients with depressive episode without diurnal rhythm(non-rhythm group) and 56 matched healthy volunteer controls(healthy group)were scanned with 3.0 T MRI Scanner.Functional connectivity (FC) were calculated between suprachiasmatic nucleus(SCN) and whole brain regions.According to results of ANOVA, group-wise two sample t-test was completed.Correlation analysis were conducted between FC of significant difference brain regions and the score of Hamilton rating scale(HAMD-24) for depression. Results The brain regions showing differences among three groups were located in the left medial superior frontal gyrus(MNI: x=0, y=39, z=51; K=14) and right cerebellum crus 1(MNI: x=39, y=-48, z=-36; K=18)(P<0.05, Alphasim). Compared with non-rhythm group, the FC of rhythm group showed significantly increased in the left medial superior frontal gyrus and right triangular inferior frontal gyrus(MNI: x=39, y=27, z=27; K=10)(P<0.05, Alphasim). Compared with healthy group, the FC of non-rhythm group showed significantly decreased in left medial superior frontal gyrus(P<0.05, Alphasim). Positive correlation was found between FC in left medial superior frontal gyrus and despair score of HAMD-24(r=0.31, P=0.041). Conclusion The synergistic increase in SCN and prefrontal activity in patients with depressive episodes with morning heavy night light rhythm which may be involved in the formation mechanism of the diurnal rhythm. Key words: Depressive episode; Diurnal rhythm; Functional magnetic resonance; Suprachiasmatic nucleus; Functional connectivity

Wild clocks: preface and glossary

The critical significance of biological timing and timekeeping is well appreciated by both chronobiologists and ecologists, and historically the two fields were linked early on (e.g. [1–3]). Sixty years ago, a diagram appeared in a book of papers from the Fifteenth Symposium for the Study of Development and Growth (figure 1; [4]) that set the stage for future research on biological time. This schematic—with daily rhythmicity generated by a ‘clock’ composed of one or more ‘endogenous self-sustained oscillators’ (ESSOs) entrained by 24-h rhythms of light and temperature—became a blueprint for research by many chronobiologists on the mechanisms of internal timekeeping within organisms. Since then, our mechanistic understanding of daily and annual timing has blossomed, now encompassing details at the molecular, cellular, tissue and organismal levels. Figure 1 also included an input from ‘residual periodic variables’ (RPVs); these were meant to represent abiotic factors such as ‘pressure, humidity, air ionization, cosmic ray showers’ [4], but could also pertain to biotic factors such as food availability, predators, competitors and mating opportunities. Since then, ecologists have demonstrated the importance of daily and annual timing for individual fitness, with deviations from optimal timing possibly resulting in reduced foraging success, survival and reproductive output. Figure 1. Block diagram of an entrained field rhythm (FR). NP, natural period. To some extent, over the next decades the research programmes of the two fields became non-overlapping, with chronobiologists focusing on unravelling the endogenous clock machinery and ecologists addressing the functional significance of timing in nature. Both by necessity and design, mechanistic work mostly has been conducted using a limited number of model organisms, each living in isolation, housed under standard (and, except for …

Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing

The association of irregular sleep schedules with circadian timing and academic performance has not been systematically examined. We studied 61 undergraduates for 30 days using sleep diaries, and quantified sleep regularity using a novel metric, the sleep regularity index (SRI). In the most and least regular quintiles, circadian phase and light exposure were assessed using salivary dim-light melatonin onset (DLMO) and wrist-worn photometry, respectively. DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular compared to Regular sleepers. A mathematical model of the circadian pacemaker and its response to light was used to demonstrate that Irregular vs. Regular group differences in circadian timing were likely primarily due to their different patterns of light exposure. A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed. These findings show that irregular sleep and light exposure patterns in college students are associated with delayed circadian rhythms and lower academic performance. Moreover, the modeling results reveal that light-based interventions may be therapeutically effective in improving sleep regularity in this population.

Scanning, Framing and Close-Up: Reimaging the Brain in 265 Looping Snapshots

This article stems from a broader research project that explored the aesthetics of magnetic resonance imaging (MRI). Here the author focuses on firsthand experience of undergoing an MRI as an experimental subject within two different laboratory projects. The self-produced video created after the two examinations, 265 Looping Snapshots, muses on the role played by MRI sound and images, the notion of surveillance and the experience of undergoing a scan. The video attempts to resist the reading of MRI as a “vision machine” for surveillance purposes. Far from being a mere representation of an inner condition unavailable to the senses, MRI images slowly become more abstract—a pulsating, rhythmical light from which other forms can emerge.

A new link between plant metabolism and circadian rhythms?

A new link between plant metabolism and circadian rhythms?

Nightless Cities: Timing the Pleasure Quarters in Early Modern Japan

This article traces the time practices relevant to Edo-period pleasure-quarter life and business in eighteenth and nineteenth century Japan, discussing two time patterns that appeared in pleasure-quarter directories at the time: more long-term, loosely circumscribed stays based around diurnal rhythms of light and darkness, as well as more short-term transactions centered on units of time measured with incense sticks—two aspects of time that were central to the trade plied in the quarters, as I show. I argue that the sex trade is significant in that it provided a rare example of a service “paid by the hour” in early modern Japan, thus crucially also calling us to (re-)consider larger issues regarding the economic value of time within the early modern Japanese world of work and especially also its relationship to modern time and labor. I demonstrate how the exigencies of a certain trade required the elaboration of a set of time units and, where necessary, a system to measure and co-ordinate them, which ultimately points towards the existence of an abstract notion of time that commanded a certain price in early modern Japan. As such, the present paper serves to qualify narratives that mainly identify the commodification of time with Japan’s industrialization, modernization, and Westernization in the late nineteenth century, as well as with the dissemination of mechanical clock-time

Rhythm Perception and Its Role in Perception and Learning of Dysrhythmic Speech.

The perception of rhythm cues plays an important role in recognizing spoken language, especially in adverse listening conditions. Indeed, this has been shown to hold true even when the rhythm cues themselves are dysrhythmic. This study investigates whether expertise in rhythm perception provides a processing advantage for perception (initial intelligibility) and learning (intelligibility improvement) of naturally dysrhythmic speech, dysarthria. Fifty young adults with typical hearing participated in 3 key tests, including a rhythm perception test, a receptive vocabulary test, and a speech perception and learning test, with standard pretest, familiarization, and posttest phases. Initial intelligibility scores were calculated as the proportion of correct pretest words, while intelligibility improvement scores were calculated by subtracting this proportion from the proportion of correct posttest words. Rhythm perception scores predicted intelligibility improvement scores but not initial intelligibility. On the other hand, receptive vocabulary scores predicted initial intelligibility scores but not intelligibility improvement. Expertise in rhythm perception appears to provide an advantage for processing dysrhythmic speech, but a familiarization experience is required for the advantage to be realized. Findings are discussed in relation to the role of rhythm in speech processing and shed light on processing models that consider the consequence of rhythm abnormalities in dysarthria.

Visual reaction effects induced and stimulated by different lights on phototactic bio-behaviors in Locusta migratoria manilensis

Control of locusts traditionally relies on chemical insecticides. However, chemical control had led to serious environment problems, while light trap techniques based on manipulating insect phototactic responses, are proposed to use for plague locusts control. The key to high efficiency of the trap is to decide the photoelectric reaction intensities on the positive phototaxis of insects. The study compared the visual reaction effects of locusts with their phototactic photosensitivity through the use of spectrometry and behavior investigations, to obtain the influences of the visual spectrum characteristics on locusts positive phototaxis. The results showed that the visual absorption of photons of mixed spectral light and the visual glimmer reaction of the locusts with migratory spectrum characteristics of the peak wavelength of LED lights, reflected the degree of the visual photosensitivity to light photons absorbed by the eye. The visual photosensitive response intensity and the phototactic aggregation effect stimulated by violet light were the most effective, showing that violet light of locusts visual trending sensitivity was consistent with the short sensitive spectrum light of insects visual electrophysiology, whereas the timeliness of the visual photosensitivity reaction and the induction effect was superior under orange light, showing that the biological behavior of locusts visual physiology reaction caused by orange light regulating locusts light rhythm was complicated. Moreover, weak light resulted in stronger visuospatial orientation in terms of the phototaxis of locusts and stronger light resulted in the better visual orientation towards the light source. The results indicated that optical wave properties could affect the visual absorption of spectral light photons, which resulted in different visual responses to different optical frequency energies and restricted the visual bio-photosensitive induction activity of locusts. The study provides new understanding of positive and negative phototaxis of locusts and useful data for the further development of photoelectric induction techniques for the control of locusts. Keywords: locusta migratoria, visual reaction effect, phototactic bio-behavior, light property, bio-control DOI: 10. 25165/j.ijabe.20171004.2357 Citation: Liu Q H, Xin Z, Zhou Q. Influences of visual reaction effect induced and stimulated by different lights on phototactic bio-behaviors in Locusta migratoria manilensis. Int J Agric & Biol Eng, 2017; 10(4): 173–181.

Light rhythms and heavy spirits: entertaining listeners through gnawa musical and ritual adaptations in Morocco

ABSTRACTMoroccan musicians conflate sacred and popular sounds within diverse and malleable rituals across the country. Their efforts are aimed at negotiating and appeasing their various audiences: clients in need of healing, family and friends looking for an evening of entertainment, and spirits building relationships with possessed bodies. Drawing on ethnographic research from Fez, Meknes and Sidi ʿAli, I show how gnawa musicians blend the boundaries between ritual and entertainment through musical innovation. Often at the behest of audiences, they perform a contemporary version of the ritual repertoire, adapt dance music rhythms into the ceremony’s music and highlight the presence of spirits that are adopted by the gnawa from other traditions. These changes demonstrate pragmatism within ritual that counters common understandings of authentic spiritual practice, blurring lines between religious and secular experience. Professional ritual musicians navigate audience expectations within a contemporary possession healing ritual by adapting their practice, subtly and overtly manipulating the event itself. The resulting innovations illuminate the nexus of listener taste and performer creativity as it influences even the most allegedly conservative musical and religious settings. They show performers reaching out to changing audiences and redefining authentic performance practice within the ritual.

Modification of Brain Oscillations via Rhythmic Light Stimulation Provides Evidence for Entrainment but Not for Superposition of Event-Related Responses.

The functional relevance of brain oscillations in the alpha frequency range (8–13 Hz) has been repeatedly investigated through the use of rhythmic visual stimulation. The underlying mechanism of the steady-state visual evoked potential (SSVEP) measured in EEG during rhythmic stimulation, however, is not known. There are two hypotheses on the origin of SSVEPs: entrainment of brain oscillations and superposition of event-related responses (ERPs). The entrainment but not the superposition hypothesis justifies rhythmic visual stimulation as a means to manipulate brain oscillations, because superposition assumes a linear summation of single responses, independent from ongoing brain oscillations. Here, we stimulated participants with a rhythmic flickering light of different frequencies and intensities. We measured entrainment by comparing the phase coupling of brain oscillations stimulated by rhythmic visual flicker with the oscillations induced by arrhythmic jittered stimulation, varying the time, stimulation frequency, and intensity conditions. In line with a theoretical concept of entrainment (the so called Arnold tongue), we found the phase coupling to be more pronounced with increasing stimulation intensity as well as at stimulation frequencies closer to each participant's intrinsic frequency. Only inside the Arnold tongue did the conditions significantly differ from the jittered stimulation. Furthermore, even in a single sequence of an SSVEP, we found non-linear features (intermittency of phase locking) that contradict the linear summation of single responses, as assumed by the superposition hypothesis. Our findings provide unequivocal evidence that visual rhythmic stimulation entrains brain oscillations, thus validating the approach of rhythmic stimulation as a manipulation of brain oscillations.

Light and maternal influence in the entrainment of activity circadian rhythm in infants 4-12 weeks of age.

The influence of light and maternal activity on early infant activity rhythm were studied in 43 healthy, maternal-infant pairs. Aims included description of infant and maternal circadian rhythm of environmental light, assessing relations among of activity and light circadian rhythm parameters, and exploring the influence of light on infant activity independent of maternal activity. Three-day light and activity records were obtained using actigraphy monitors at infant ages 4, 8, and 12 weeks. Circadian rhythm timing, amplitude, 24-hour fit, rhythm center, and regularity were determined using cosinor and nonparametric circadian rhythm analyses (NPCRA). All maternal and infant circadian parameters for light were highly correlated. When maternal activity was controlled, the partial correlations between infant activity and light rhythm timing, amplitude, 24-hour fit, and rhythm center demonstrated significant relation (r = .338 to .662) at infant age 12 weeks, suggesting entrainment. In contrast, when maternal light was controlled there was significant relation between maternal and infant activity rhythm (r = 0.470, 0.500, and 0.638 at 4, 8 and 12 weeks, respectively) suggesting the influence of maternal-infant interaction independent of photo entrainment of cycle timing over the first 12 weeks of life. Both light and maternal activity may offer avenues for shaping infant activity rhythm during early infancy.

Sustained Circadian Rhythms in Continuous Light in Synechocystis sp. PCC6803 Growing in a Well-Controlled Photobioreactor.

The cyanobacterial circadian clock has been well-studied and shown to be both robust and a dominant factor in the control of gene expression in Synechococcus elongatus PCC7942. In Synechocystis sp. PCC6803, the circadian clock is assumed to function similarly, yet appears to control transcription to a far lesser extent and its circadian rhythm was reported to not be sustained, or at least rapidly damped, under continuous illumination. One of the feedback loops that governs the clock in S. elongatus in addition to the core oscillator, i.e., the transcriptional-translation regulation loop hinging on KaiC-dependent expression of kaiBC, appears to be missing in Synechocystis, which would account for this difference. Here, we show that the clock in Synechocystis fulfills all criteria of a circadian clock: 1) a free-running period of approximately 24 h, 2) temperature compensation, and 3) being able to be entrained. A remarkably stable rhythm is generated despite the fact that the organism grows with a doubling time of less than 24 h in a photobioreactor run in turbidostat mode. No damping of the free-running circadian oscillation was observed in 2 weeks, suggesting that the clock in individual cells stays synchronized within a culture despite the apparent lack of a transcriptional-translation regulation loop. Furthermore, the dependence of chlorophyll synthesis on the presence of O2 was demonstrated.

Sensitive Chaos

This paper describes the life (and death) of the interface in the installation Tiny Moments by David Strang. Tiny Moments is a sound and light interactive installation that explores natural phenomena surrounding heat, ice and presence/ proximity. This installation explores the process of natural materials in computer interaction in a way beyond simple hardware devices available to users. What is created is a space filled with ever changing rhythms of light and sound in complete synchronicity that no user feels to have any control of.

Development of Meynert Cells in the Cat Visual Cortex in Conditions of Stimulation with Flashing Light

The effects of rhythmic light stimulation on the postnatal development of the visual system were studied in relation to the formation of Meynert neurons in field 17 and the posteromedial area of the lateral suprasylvian sulcus (PMLS) in kittens reared with exposure to flashing light (frequency 15 Hz). Neuron body cross-sectional area and cytochrome oxidase (CO) activity levels were measured in the visual cortex of control (n = 6) and stimulated (n = 6) animals. Increases in the level of CO activity were seen in Meynert cells in field 17 and the PMLS area, by about 37%. There was also a decrease in the cross-sectional area of the bodies of Meynert neurons located in the PMLS, by 20% compared with normal. The existence of functional impairments of the Y conducting channel in stimulated animals and the possibility that binocular vision is suppressed are discussed.

Association between Obesity and Circadian Clock

Data from World Health Organization show that: worldwide obesity has more than doubled since 1980; in 2014, more than 1.9 billion adults, 18 years and older, were overweight, of these over 600 million were obese; 39% of adults aged 18 years and over were overweight in 2014, and 13% were obese; 42 million children under the age of 5 were overweight or obese in 2013 [1]. The aim of this comment is to make a brief review of the research on circadian rhythm and their participation in the development of obesity in humans. Recent findings onto the molecular, genetic, neural, and physiologic basis for the generation and organization of circadian clocks in mammals have revealed interactions between the circadian clock system and critical pathways for the regulation of metabolism and energy balance [2]. Circadian rhythmicity that has been shaped by evolution over millions of years generates an internal timing controlling the sleepwake and metabolism cycles [3]. Also, life on earth has evolved under the daily rhythm of light and dark. Consequently, most creatures experience a daily rhythm in food availability [4].

Music therapy in neurological rehabilitation settings.

The neurologic music therapy is a new scope of music therapy. Its techniques deal with dysfunctions resulting from diseases of the human nervous system. Music can be used as an alternative modality to access functions unavailable through non-musical stimulus. Processes in the brain activated by the influence of music can be generalized and transferred to non-musical functions. Therefore, in clinical practice, the translation of non-musical therapeutic exercises into analogous, isomorphic musical exercises is performed. They make use of the executive peculiarity of musical instruments and musical structures to prime, cue and coordinate movements. Among musical components, a repetitive rhythm plays a significant role. It regulates physiologic and behavioural functions through the mechanism of entrainment (synchronization of biological rhythms with musical rhythm based on acoustic resonance). It is especially relevant for patients with a deficient internal timing system in the brain. Additionally, regular rhythmic patterns facilitate memory encoding and decoding of non-musical information hence music is an efficient mnemonic tool. The music as a hierarchical, compound language of time, with its unique ability to access affective/motivational systems in the brain, provides time structures enhancing perception processes, mainly in the range of cognition, language and motor learning. It allows for emotional expression and improvement of the motivation for rehabilitation activities. The new technologies of rhythmic sensory stimulation (i.e. Binaural Beat Stimulation) or rhythmic music in combination with rhythmic light therapy appear. This multimodal forms of stimulation are used in the treatment of stroke, brain injury, dementia and other cognitive deficits. Clinical outcome studies provide evidence of the significant superiority of rehabilitation with music over the one without music.