scholarly journals Retina-attached slice recording reveals light-triggered tonic GABA signaling in suprachiasmatic nucleus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jea Kwon ◽  
Minwoo Wendy Jang ◽  
C. Justin Lee
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Light Exposure ◽  
Critical Role ◽  
Internal Clock ◽  
Time Interval ◽  
Light Illumination ◽  
Electrophysiological Properties ◽  
Gaba Signaling ◽  
Spatio Temporal ◽  
Highly Correlated

AbstractLight is a powerful external cue modulating the biological rhythm of internal clock neurons in the suprachiasmatic nucleus (SCN). GABA signaling in SCN is critically involved in this process. Both phasic and tonic modes of GABA signaling exist in SCN. Of the two modes, the tonic mode of GABA signaling has been implicated in light-mediated synchrony of SCN neurons. However, modulatory effects of external light on tonic GABA signalling are yet to be explored. Here, we systematically characterized electrophysiological properties of the clock neurons and determined the spatio-temporal profiles of tonic GABA current. Based on the whole-cell patch-clamp recordings from 76 SCN neurons, the cells with large tonic GABA current (>15 pA) were more frequently found in dorsal SCN. Moreover, tonic GABA current in SCN was highly correlated with the frequency of spontaneous inhibitory postsynaptic current (sIPSC), raising a possibility that tonic GABA current is due to spill-over from synaptic release. Interestingly, tonic GABA current was inversely correlated with slice-to-patch time interval, suggesting a critical role of retinal light exposure in intact brain for an induction of tonic GABA current in SCN. To test this possibility, we obtained meticulously prepared retina-attached SCN slices and successfully recorded tonic and phasic GABA signaling in SCN neurons. For the first time, we observed an early-onset, long-lasting tonic GABA current, followed by a slow-onset, short-lasting increase in the phasic GABA frequency, upon direct light-illumination of the attached retina. This result provides the first evidence that external light cue can directly trigger both tonic and phasic GABA signaling in SCN cell. In conclusion, we propose tonic GABA as the key mediator of external light in SCN.

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

scholarly journals Precision Light for the Treatment of Psychiatric Disorders

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Sevag Kaladchibachi ◽  
Fabian Fernandez
Keyword(s):  
Psychiatric Disorders ◽  
Brain Function ◽  
Seasonal Affective Disorder ◽  
Light Exposure ◽  
Bright Light ◽  
Internal Clock ◽  
Light Pulses ◽  
Current Review ◽  
Flexible Architectures ◽  
Bright Light Exposure

Circadian timekeeping can be reset by brief flashes of light using stimulation protocols thousands of times shorter than those previously assumed to be necessary for traditional phototherapy. These observations point to a future where flexible architectures of nanosecond-, microsecond-, and millisecond-scale light pulses are compiled to reprogram the brain’s internal clock when it has been altered by psychiatric illness or advanced age. In the current review, we present a chronology of seminal experiments that established the synchronizing influence of light on the human circadian system and the efficacy of prolonged bright-light exposure for reducing symptoms associated with seasonal affective disorder. We conclude with a discussion of the different ways that precision flashes could be parlayed during sleep to effect neuroadaptive changes in brain function. This article is a contribution to a special issue onCircadian Rhythms in Regulation of Brain Processes and Role in Psychiatric Disorderscurated by editors Shimon Amir, Karen Gamble, Oliver Stork, and Harry Pantazopoulos.

Color Processing in Macaque Striate Cortex: Electrophysiological Properties

2002 ◽  
Vol 87 (6) ◽  
pp. 3138-3151 ◽  
Author(s):  
Carole E. Landisman ◽  
Daniel Y. Ts'O
Keyword(s):  
Optical Imaging ◽  
Cytochrome Oxidase ◽  
Striate Cortex ◽  
Color Patch ◽  
Color Processing ◽  
Color Properties ◽  
Electrophysiological Properties ◽  
Color Opponency ◽  
One To One ◽  
Highly Correlated

We have shown in the accompanying paper that optical imaging of macaque striate cortex reveals patches that are preferentially activated by equiluminant chromatic gratings compared with luminance gratings. These imaged color patches are highly correlated, although not always in one-to-one correspondence, with the cytochrome-oxidase (CO) blobs. In the present study, we have investigated the electrophysiological properties of neurons in the imaged color patches and the CO blobs. Our results indicate that individual blobs tend to contain cells of only one type of color opponency: either red/green or blue/yellow. Individual imaged color patches, however, can bridge blobs of similar opponency or differing opponency. When imaged color patches contain two blobs of differing opponency, the cells in the bridge region exhibit mixed color properties that are not opponent along the two cardinal color axes (either red/green or blue/yellow). Two blobs within a single imaged color patch receive input from the same eye or from different eyes. In the latter case, the bridge region between blobs contains binocular cells that are color selective. Because the cells recorded in imaged color patches were more color selective and unoriented than cells outside of color patches, color properties appear to be organized in a clustered and segregated fashion in primate V1.

scholarly journals Time perception and age

2016 ◽  
Vol 74 (4) ◽  
pp. 299-302 ◽  
Author(s):  
Vanessa Fernanda Moreira Ferreira ◽  
Gabriel Pina Paiva ◽  
Natália Prando ◽  
Carla Renata Graça ◽  
João Aris Kouyoumdjian
Keyword(s):  
Time Perception ◽  
Healthy Subjects ◽  
Age Groups ◽  
Internal Clock ◽  
Time Interval ◽  
Comparison Test ◽  
Clock System ◽  
Multiple Comparison Test ◽  
The Common ◽  
Bonferroni Multiple Comparison Test

ABSTRACT Our internal clock system is predominantly dopaminergic, but memory is predominantly cholinergic. Here, we examined the common sensibility encapsulated in the statement: “time goes faster as we get older”. Objective To measure a 2 min time interval, counted mentally in subjects of different age groups. Method 233 healthy subjects (129 women) were divided into three age groups: G1, 15-29 years; G2, 30-49 years; and G3, 50-89 years. Subjects were asked to close their eyes and mentally count the passing of 120 s. Results The elapsed times were: G1, mean = 114.9 ± 35 s; G2, mean = 96.0 ± 34.3 s; G3, mean = 86.6 ± 34.9 s. The ANOVA-Bonferroni multiple comparison test showed that G3 and G1 results were significantly different (P < 0.001). Conclusion Mental calculations of 120 s were shortened by an average of 24.6% (28.3 s) in individuals over age 50 years compared to individuals under age 30 years.

scholarly journals An automatic estimation of the rest-interval for MotionWatch8© using uniaxial movement and lux data

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Daniel Backhouse ◽  
Ryan Stanley Falck ◽  
Teresa Liu-Ambrose
Keyword(s):  
Older Adults ◽  
Sleep Duration ◽  
Light Exposure ◽  
Objective Measure ◽  
Self Report ◽  
Time Interval ◽  
Poor Sleep ◽  
Rest Interval ◽  
Scoring Method ◽  
Field Methods

Abstract Background Poor sleep is linked with chronic conditions common in older adults, including diabetes, heart disease, and dementia. Valid and reliable field methods to objectively measure sleep are thus greatly needed to examine how poor sleep impacts older adults. Wrist-worn actigraphy (WWA) is a common objective measure of sleep that uses motion and illuminance data to estimate sleep. The rest-interval marks the time interval between when an individual attempts to sleep and the time they get out of bed to start their day. Traditionally, the rest-interval is scored manually by trained technicians, however algorithms currently exist which automatically score WWA data, saving time and providing consistency from user-to-user. However, these algorithms ignore illuminance data and only considered motion in their estimation of the rest-interval. This study therefore examines a novel algorithm that uses illuminance data to supplement the approximation of the rest-interval from motion data. Methods We examined a total of 1086 days of data of 129 participants who wore the MotionWatch8© WWA for ≥14 nights of observation. Resultant sleep measures from three different parameter settings were compared to sleep measures derived following a standard scoring protocol and self-report times. Results The algorithm showed the strongest correlation to the standard protocol (r = 0.92 for sleep duration). There were no significant differences in sleep duration, sleep efficiency and fragmentation index estimates compared to the standard scoring protocol. Conclusion These results suggest that an automated rest-interval scoring method using both light exposure and acceleration data provides comparable accuracy to the standard scoring method.

K2: A Novel Data Analysis Framework to Understand US Emotions in Space and Time

2019 ◽  
Vol 13 (01) ◽  
pp. 111-133
Author(s):  
Romita Banerjee ◽  
Karima Elgarroussi ◽  
Sujing Wang ◽  
Akhil Talari ◽  
Yongli Zhang ◽  
...  
Keyword(s):  
Data Analysis ◽  
Negative Emotion ◽  
Time Interval ◽  
Temporal Data ◽  
Analysis Framework ◽  
Spatial Clusters ◽  
Change Analysis ◽  
Spatio Temporal ◽  
Temporal Data Analysis ◽  
Very High

Twitter is one of the most popular social media platforms used by millions of users daily to post their opinions and emotions. Consequently, Twitter tweets have become a valuable knowledge source for emotion analysis. In this paper, we present a new framework, K2, for tweet emotion mapping and emotion change analysis. It introduces a novel, generic spatio-temporal data analysis and storytelling framework that can be used to understand the emotional evolution of a specific section of population. The input for our framework is the location and time of where and when the tweets were posted and an emotion assessment score in the range [Formula: see text], with [Formula: see text] representing a very high positive emotion and [Formula: see text] representing a very high negative emotion. Our framework first segments the input dataset into a number of batches with each batch representing a specific time interval. This time interval can be a week, a month or a day. By generalizing existing kernel density estimation techniques in the next step, we transform each batch into a continuous function that takes positive and negative values. We have used contouring algorithms to find the contiguous regions with highly positive and highly negative emotions belonging to each member of the batch. Finally, we apply a generic, change analysis framework that monitors how positive and negative emotion regions evolve over time. In particular, using this framework, unary and binary change predicate are defined and matched against the identified spatial clusters, and change relationships will then be recorded, for those spatial clusters for which a match occurs. We also propose animation techniques to facilitate spatio-temporal data storytelling based on the obtained spatio-temporal data analysis results. We demo our approach using tweets collected in the state of New York in the month of June 2014.

scholarly journals Joseph Schumpeter Lecture, EEA Annual Congress 2017: Do Tax Cuts Produce more Einsteins? The Impacts of Financial Incentives VerSus Exposure to Innovation on the Supply of Inventors

2019 ◽  
Vol 17 (3) ◽  
pp. 651-677 ◽  
Author(s):  
Alex Bell ◽  
Raj Chetty ◽  
Xavier Jaravel ◽  
Neviana Petkova ◽  
John Van Reenen
Keyword(s):  
Career Choice ◽  
Financial Incentives ◽  
Social Impact ◽  
Critical Role ◽  
The United States ◽  
High Impact ◽  
Childhood Exposure ◽  
Income Distributions ◽  
Career Trajectories ◽  
Highly Correlated

Abstract Many countries provide financial incentives to spur innovation, ranging from tax incentives to research and development grants. In this paper, we study how such financial incentives affect individuals’ decisions to pursue careers in innovation. We first present empirical evidence on inventors’ career trajectories and income distributions using deidentified data on 1.2 million inventors from patent records linked to tax records in the United States. We find that the private returns to innovation are extremely skewed—with the top 1% of inventors collecting more than 22% of total inventors’ income—and are highly correlated with their social impact, as measured by citations. Inventors tend to have their most impactful innovations around age 40 and their incomes rise rapidly just before they have high-impact patents. We then build a stylized model of inventor career choice that matches these facts as well as recent evidence that childhood exposure to innovation plays a critical role in determining whether individuals become inventors. The model predicts that financial incentives, such as top income tax reductions, have limited potential to increase aggregate innovation because they only affect individuals who are exposed to innovation and have essentially no impact on the decisions of star inventors, who matter most for aggregate innovation. Importantly, these results hold regardless of whether the private returns to innovation are fully known at the time of career choice or are fully stochastic. In contrast, increasing exposure to innovation (e.g., through mentorship programs) could have substantial impacts on innovation by drawing individuals who produce high-impact inventions into the innovation pipeline. Although we do not present direct evidence supporting these model-based predictions, our results call for a more careful assessment of the impacts of financial incentives and a greater focus on alternative policies to increase the supply of inventors.

scholarly journals Machine Learning Methods for Seismic Hazards Forecast

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 308 ◽  
Author(s):  
Valeri G. Gitis ◽  
Alexander B. Derendyaev
Keyword(s):  
Machine Learning ◽  
Training Sample ◽  
Time Interval ◽  
Minimum Area ◽  
Learning Methods ◽  
Web Based ◽  
Strong Earthquakes ◽  
Machine Learning Methods ◽  
Regression Approach ◽  
Spatio Temporal

In this paper, we suggest two machine learning methods for seismic hazard forecast. The first method is used for spatial forecasting of maximum possible earthquake magnitudes ( M m a x ), whereas the second is used for spatio-temporal forecasting of strong earthquakes. The first method, the method of approximation of interval expert estimates, is based on a regression approach in which values of M m a x at the points of the training sample are estimated by experts. The method allows one to formalize the knowledge of experts, to find the dependence of M m a x on the properties of the geological environment, and to construct a map of the spatial forecast. The second method, the method of minimum area of alarm, uses retrospective data to identify the alarm area in which the epicenters of strong (target) earthquakes are expected at a certain time interval. This method is the basis of an automatic web-based platform that systematically forecasts target earthquakes. The results of testing the approach to earthquake prediction in the Mediterranean and Californian regions are presented. For the tests, well known parameters of earthquake catalogs were used. The method showed a satisfactory forecast quality.

scholarly journals Dynamics of Photogenerated Charge Carriers in TiO2/MoO3, TiO2/WO3 and TiO2/V2O5 Photocatalysts with Mosaic Structure

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1022
Author(s):  
Alexander I. Kokorin ◽  
Tatyana V. Sviridova ◽  
Elizaveta A. Konstantinova ◽  
Dmitry V. Sviridov ◽  
Detlef W. Bahnemann
Keyword(s):  
Light Exposure ◽  
Low Cost ◽  
Energy Levels ◽  
Charge Trapping ◽  
Bactericidal Effect ◽  
High Reactivity ◽  
Charge Carriers ◽  
Light Illumination ◽  
Uv Illumination ◽  
Photocatalytic Material

Titania is a widely used photocatalytic material possessing such advantages as low cost and high reactivity under the ultraviolet light illumination. However, the fast recombination of photoexcited charge carriers limits its application. Herein, we have synthesized original nanomaterials with mosaic structures that exhibited well-defined heterojunctions and new properties. Using SEM, XRD, EPR spectroscopy, photocatalytic measurements, and photoinduced pathphysiological activity of these photocatalysts, we studied the processes of charge carrier accumulation in TiO2/MoO3, TiO2/WO3, and TiO2/V2O5 under in situ UV illumination with emphasis on the charge exchange between energy levels of these nanosized semiconductors. It is shown that the accumulation of photoinduced charges occurs in two forms (i) filled electron traps corresponding to Ti4+/Ti3+ levels and (ii) Mo5+ centers, both forms contributing to the photoinduced biocide activity of the samples. This work demonstrates that light exposure of heterostructure photocatalysts with mosaic surfaces produces different types of charge-trapping centers capable of interacting with molecular oxygen yielding peroxo species, which provide long-life light-induced ”self-cleaning” behavior. Such photoaccumulating materials open new opportunities in developing light-driven self-sterilization structures exhibiting a prolonged bactericidal effect up to 10 h after stopping light exposure.

Photic resetting of intrinsic rhythmicity of the rat suprachiasmatic nucleus under various photoperiods

1998 ◽  
Vol 274 (3) ◽  
pp. R857-R863 ◽  
Author(s):  
Alena Sumová ◽  
Helena Illnerová
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Dark Period ◽  
Light Exposure ◽  
Light Stimulus ◽  
Phase Shifts ◽  
Late Night ◽  
Fos Protein ◽  
Endogenous Rhythmicity ◽  
Protein Immunoreactivity ◽  
First Time

To date, photic entrainment of the mammalian circadian system has been studied by following phase shifts of overt rhythms in the periphery governed by a circadian pacemaker located in the suprachiasmatic nucleus (SCN). The present study follows for the first time photic resetting of intrinsic rhythmicity of the SCN itself. Rats maintained under either a shorter photoperiod, with 12 h of light and 12 h of darkness per day, or under a long, 18:6-h light-dark photoperiod were exposed to a light stimulus during the dark period and then released into darkness, and the next day the SCN rhythm in the light-stimulated c-Fos protein immunoreactivity was followed as a marker of the SCN endogenous rhythmicity. After a light stimulus in the early night, the evening rise in the photic elevation of Fos protein photoinduction as well as the morning decline were phase delayed within one cycle. After a light stimulus in the late night, only the morning decline in the photic elevation of Fos was phase advanced the next night, not the evening rise; consequently, the interval enabling high photic elevation of Fos was reduced. After a light stimulus was administered around the middle of the night, the next night the evening rise in the light-stimulated Fos was eventually phase delayed, the morning decline was phase advanced, and the rhythm amplitude was reduced significantly; under 18:6-h light-dark, a mere 5-min light exposure exhibited such effects. The data indicate that resetting of the SCN rhythmicity in the light-elevated c-Fos 1 day after a resetting stimulus administration, i.e., during transient cycles, may proceed via nonparallel phase shifts of the evening rise and of the morning decline of the light-stimulated Fos, and via amplitude lowering and suggest a complex circadian pacemaking system in the rat SCN.

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