scholarly journals Modulation of recognition memory performance by light requires both melanopsin and classical photoreceptors

2016 ◽  
Vol 283 (1845) ◽  
pp. 20162275 ◽  
Author(s):  
Shu K. E. Tam ◽  
Sibah Hasan ◽  
Steven Hughes ◽  
Mark W. Hankins ◽  
Russell G. Foster ◽  
...  
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Memory Performance ◽  
Recognition Task ◽  
Bright Light ◽  
Brain Network ◽  
Network Activity ◽  
Effect Of Light

Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as direction, of the effect depending on the nature of the task. Similarly, in nocturnal rodents, bright light can either facilitate or disrupt performance depending on the type of task employed. Crucially, it is unclear whether the effects of light on behavioural performance are mediated via the classical image-forming rods and cones or the melanopsin-expressing photosensitive retinal ganglion cells. Here, we investigate the modulatory effects of light on memory performance in mice using the spontaneous object recognition task. Importantly, we examine which photoreceptors are required to mediate the effects of light on memory performance. By using a cross-over design, we show that object recognition memory is disrupted when the test phase is conducted under a bright light (350 lux), regardless of the light level in the sample phase (10 or 350 lux), demonstrating that exposure to a bright light at the time of test, rather than at the time of encoding, impairs performance. Strikingly, the modulatory effect of light on memory performance is completely abolished in both melanopsin-deficient and rodless–coneless mice. Our findings provide direct evidence that melanopsin-driven and rod/cone-driven photoresponses are integrated in order to mediate the effect of light on memory performance.

scholarly journals NTRK2methylation is related to reduced PTSD risk in two African cohorts of trauma survivors

2020 ◽  
Vol 117 (35) ◽  
pp. 21667-21672
Author(s):  
Vanja Vukojevic ◽  
David Coynel ◽  
Navid R. Ghaffari ◽  
Virginie Freytag ◽  
Thomas Elbert ◽  
...  
Keyword(s):  
Recognition Memory ◽  
Memory Performance ◽  
Brain Network ◽  
Network Activity ◽  
Trauma Survivors ◽  
Ptsd Symptoms ◽  
African Populations ◽  
Tropomyosin Related Kinase B ◽  
The Relationship ◽  
With Memory

Extensive pharmacologic, genetic, and epigenetic research has linked the glucocorticoid receptor (GR) to memory processes, and to risk and symptoms of posttraumatic stress disorder (PTSD). In the present study we investigated the epigenetic pattern of 12 genes involved in the regulation of GR signaling in two African populations of heavily traumatized individuals: Survivors of the rebel war in northern Uganda (n= 463) and survivors of the Rwandan genocide (n= 350). The strongest link between regional methylation and PTSD risk and symptoms was observed forNTRK2, which encodes the transmembrane receptor tropomyosin-related kinase B, binds the brain-derived neurotrophic factor, and has been shown to play an important role in memory formation.NTRK2methylation was not related to trauma load, suggesting that methylation differences preexisted the trauma. BecauseNTRK2methylation differences were predominantly associated with memory-related PTSD symptoms, and because they seem to precede traumatic events, we next investigated the relationship betweenNTRK2methylation and memory in a sample of nontraumatized individuals (n= 568). We found thatNTRK2methylation was negatively associated with recognition memory performance. Furthermore, fMRI analyses revealedNTRK2methylation-dependent differences in brain network activity related to recognition memory. The present study demonstrates thatNTRK2is epigenetically linked to memory functions in nontraumatized subjects and to PTSD risk and symptoms in traumatized populations.

scholarly journals Fundamentals of circadian entrainment by light

2021 ◽  
Vol 53 (5) ◽  
pp. 377-393
Author(s):  
RG Foster
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Evidence Based ◽  
Retinal Ganglion ◽  
Rods And Cones ◽  
Long Duration ◽  
Lighting Systems ◽  
Short Wavelength Light ◽  
Wavelength Light

Light at dawn and dusk is the key signal for the entrainment of the circadian clock. Light at dusk delays the clock. Light at dawn advances the clock. The threshold for human entrainment requires relatively bright light for a long duration, but the precise irradiance/duration relationships for photoentrainment have yet to be fully defined. Photoentrainment is achieved by a network of photosensitive retinal ganglion cells (pRGCs) which utilise the short-wavelength light-sensitive photopigment, melanopsin. Although rods and cones are not required, they do play a role in photoentrainment, by projecting to and modulating the endogenous photosensitivity of the pRGCs, but in a manner that remains poorly understood. It is also important to emphasise that the age and prior light exposure of an individual will modify the efficacy of entrainment stimuli. Because of the complexity of photoreceptor interactions, attempts to develop evidence-based human centric lighting are not straightforward. We need to study how humans respond to dynamic light exposure in the ‘real world’ where light intensity, duration, spectral quality and the time of exposure vary greatly. Defining these parameters will allow the development of electric lighting systems that will enhance human circadian entrainment.

What three-year-olds remember from their past

2016 ◽  
Vol 41 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Monika Hirte ◽  
Frauke Graf ◽  
Ziyon Kim ◽  
Monika Knopf
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Recognition Task ◽  
Deferred Imitation ◽  
Related Information ◽  
Two Samples ◽  
Task Recognition ◽  
Long Term Retention ◽  
Memory Contents

From birth on, infants show long-term recognition memory for persons. Furthermore, infants from six months onwards are able to store and retrieve demonstrated actions over long-term intervals in deferred imitation tasks. Thus, information about the model demonstrating the object-related actions is stored and recognition memory for the objects as well as memory for the actions is retrieved. To study the development of long-term retention for different memory contents systematically, the present study investigated the recognition of person- and object-related information as well as the retention of actions in two samples of three-year-olds who had participated in a deferred imitation task at either nine or 18 months of age. Results showed that three-year-olds who had participated at nine months of age retained actions in a re-enactment task; however, they neither indicated person- nor object-recognition in a picture-choice task (recognition task). Children who had participated at 18 months of age demonstrated person- and object-recognition but no re-enactment at three years of age. Findings are discussed against the background of memory development from a preverbal to a verbal age and in regard to the characteristics of the recognition vs re-enactment tasks and the stimuli used.

scholarly journals Acute effects of naturalistic THC vs. CBD use on recognition memory: a preliminary study

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Tim Curran ◽  
Hélène Devillez ◽  
Sophie L. YorkWilliams ◽  
L. Cinnamon Bidwell
Keyword(s):  
Recognition Memory ◽  
Memory Performance ◽  
Recognition Task ◽  
Blood Levels ◽  
Dependent Manner ◽  
Acute Effects ◽  
Blood Draw ◽  
Memory Impairments ◽  
Verbal Recognition ◽  
Memory Accuracy

Abstract The ratio of ∆9-tetrahydrocannabinol (THC) to cannabidiol (CBD) varies widely across cannabis strains. CBD has opposite effects to THC on a variety of cognitive functions, including acute THC-induced memory impairments. However, additional data are needed, especially under naturalistic conditions with higher potency forms of cannabis, commonly available in legal markets. The goal of this study was to collect preliminary data on the acute effects of different THC:CBD ratios on memory testing in a brief verbal recognition task under naturalistic conditions, using legal-market Colorado dispensary products. Thirty-two regular cannabis users consumed cannabis of differing THC and CBD levels purchased from a dispensary and were assessed via blood draw and a verbal recognition memory test both before (pretest) and after (posttest) ad libitum home administration in a mobile laboratory. Memory accuracy decreased as post-use THC blood levels increased (n = 29), whereas performance showed no relationship to CBD blood levels. When controlling for post-use THC blood levels as a covariate, participants using primarily THC-based strains showed significantly worse memory accuracy post-use, whereas subjects using strains containing both THC and CBD showed no differences between pre- and post-use memory performance. Using a brief and sensitive verbal recognition task, our study demonstrated that naturalistic, acute THC use impairs memory in a dose dependent manner, whereas the combination of CBD and THC was not associated with impairment.

scholarly journals Circadian Photoentrainment in Mice and Humans

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 180
Author(s):  
Russell G. Foster ◽  
Steven Hughes ◽  
Stuart N. Peirson
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Functional Expression ◽  
Time Of Day ◽  
High Irradiance ◽  
Intermittent Light ◽  
Long Duration ◽  
Light History

Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.

scholarly journals Hippocampal Infusion of Zeta Inhibitory Peptide Impairs Recent, but Not Remote, Recognition Memory in Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jena B. Hales ◽  
Amber C. Ocampo ◽  
Nicola J. Broadbent ◽  
Robert E. Clark
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Spatial Memory ◽  
Dorsal Hippocampus ◽  
Late Phase ◽  
Recognition Task ◽  
Long Term Potentiation ◽  
Inhibitory Peptide ◽  
Term Potentiation ◽  
Novel Object Recognition Task

Spatial memory in rodents can be erased following the infusion of zeta inhibitory peptide (ZIP) into the dorsal hippocampus via indwelling guide cannulas. It is believed that ZIP impairs spatial memory by reversing established late-phase long-term potentiation (LTP). However, it is unclear whether other forms of hippocampus-dependent memory, such as recognition memory, are also supported by hippocampal LTP. In the current study, we tested recognition memory in rats following hippocampal ZIP infusion. In order to combat the limited targeting of infusions via cannula, we implemented a stereotaxic approach for infusing ZIP throughout the dorsal, intermediate, and ventral hippocampus. Rats infused with ZIP 3–7 days after training on the novel object recognition task exhibited impaired object recognition memory compared to control rats (those infused with aCSF). In contrast, rats infused with ZIP 1 month after training performed similar to control rats. The ability to form new memories after ZIP infusions remained intact. We suggest that enhanced recognition memory for recent events is supported by hippocampal LTP, which can be reversed by hippocampal ZIP infusion.

scholarly journals Multisensory gains in simple detection predict global cognition in schoolchildren

2019 ◽  
Author(s):  
Solange Denervaud ◽  
Edouard Gentaz ◽  
Pawel J Matusz ◽  
Micah M. Murray
Keyword(s):  
Cognitive Development ◽  
Recognition Memory ◽  
Fluid Intelligence ◽  
Multisensory Processing ◽  
Memory Performance ◽  
Recognition Task ◽  
Detection Task ◽  
Simple Detection ◽  
Global Cognition ◽  
Multisensory Processes

The capacity to integrate information from different senses is central for coherent perception across the lifespan from infancy onwards. Later in life, multisensory processes are related to cognitive functions, such as speech or social communication. During learning, multisensory processes can in fact enhance subsequent recognition memory for unisensory objects. These benefits can even be predicted; adults’ recognition memory performance is shaped by earlier responses in the same task to multisensory – but not unisensory – information. Everyday environments where learning occurs, such as classrooms, are inherently multisensory in nature. Multisensory processes may therefore scaffold healthy cognitive development. Here, we provide the first evidence of a predictive relationship between multisensory benefits in simple detection and higher-level cognition that is present already in schoolchildren. Multiple regression analyses indicated that the extent to which a child (N=68; aged 4.5 –15years) exhibited multisensory benefits on a simple detection task not only predicted benefits on a continuous recognition task involving naturalistic objects (p=0.009), even when controlling for age. The same relative multisensory benefit also predicted working memory scores (p=0.023) and fluid intelligence scores (p=0.033) as measured using age-standardised test batteries. By contrast, gains in unisensory detection did not show significant prediction of any of the above global cognition measures. Our findings show that low-level multisensory processes predict higher-order memory and cognition already during childhood, even if still subject to ongoing maturation. These results call for revision of traditional models of cognitive development (and likely also education) to account for the role of multisensory processing, while also opening exciting opportunities to facilitate early learning through multisensory programs. More generally, these data suggest that a simple detection task could provide direct insights into the integrity of global cognition in schoolchildren and could be further developed as a readily-implemented and cost-effective screening tool for neurodevelopmental disorders, particularly in cases when standard neuropsychological tests are infeasible or unavailable.

scholarly journals luox: novel open-access and open-source web platform for calculating and sharing physiologically relevant quantities for light and lighting

2021 ◽  
Vol 6 ◽  
pp. 69
Author(s):  
Manuel Spitschan ◽  
James Mead ◽  
Chris Roos ◽  
Chris Lowis ◽  
Ben Griffiths ◽  
...  
Keyword(s):  
Open Access ◽  
Open Source ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Research Area ◽  
Visual Responses ◽  
Highly Active ◽  
Architectural Lighting ◽  
Active Research

Light exposure has a profound impact on human physiology and behaviour. For example, light exposure at the wrong time can disrupt our circadian rhythms and acutely suppress the production of melatonin. In turn, appropriately timed light exposure can support circadian photoentrainment. Beginning with the discovery that melatonin production is acutely suppressed by bright light more than 40 years ago, understanding which aspects of light drive the 'non-visual' responses to light remains a highly active research area, with an important translational dimension and implications for "human-centric" or physiologically inspired architectural lighting design. In 2018, the International Commission on Illumination (CIE) standardised the spectral sensitivities for predicting the non-visual effects of a given spectrum of light with respect to the activation of the five photoreceptor classes in the human retina: the L, M and S cones, the rods, and the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). Here, we described a novel, lean, user-friendly, open-access and open-source platform for calculating quantities related to light. The platform, called luox, enables researchers and research users in chronobiology, sleep research and adjacent field to turn spectral measurements into reportable quantities. The luox code base, released under the GPL-3.0 License, is modular and therefore extendable to other spectrum-derived quantities.

Light, Sleep, and Development

PEDIATRICS ◽  
1987 ◽  
Vol 79 (6) ◽  
pp. 1053-1054
Author(s):  
PENNY GLASS ◽  
GORDON B. AVERY
Keyword(s):  
Intensive Care ◽  
Rem Sleep ◽  
Light Exposure ◽  
Bright Light ◽  
Retinal Damage ◽  
Sleep State ◽  
Intensive Care Nursery ◽  
Light Sleep ◽  
Effect Of Light

In Reply.— Sheldon and Bell express concern for the effect of uncycled nursery light on sleep state and biorhythms in infants. Their concerns seem well founded. A variety of evidence suggests that the effect of light exposure in the intensive care nursery goes beyond the potential for retinal damage. For example, we found differences in sleep state for infants exposed to bright v dim ambient nursery light.1 Bright light was associated with significantly greater amounts of active-REM sleep.

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