scholarly journals 40-Hz Blue Light Changes Hippocampal Activation and Functional Connectivity Underlying Recognition Memory

2021 ◽  
Vol 15 ◽  
Author(s):  
Zhenglong Lin ◽  
Gangqiang Hou ◽  
Youli Yao ◽  
Zhifeng Zhou ◽  
Feiqi Zhu ◽  
...  

Research on light modulation has typically examined the wavelength, intensity, and exposure time of light, and measured rhythm, sleep, and cognitive ability to evaluate the regulatory effects of light variables on physiological and cognitive functions. Although the frequency of light is one of the main dimensions of light, few studies have attempted to manipulate it to test the effect on brain activation and performance. Recently, 40-Hz light stimulation has been proven to significantly alleviate deficits in gamma oscillation of the hippocampus caused by Alzheimer’s disease. Although this oscillation is one of the key functional characteristics of performing memory tasks in healthy people, there is no evidence that 40-Hz blue light exposure can effectively regulate brain activities related to complex cognitive tasks. In the current study, we examined the difference in the effects of 40-Hz light or 0-Hz light exposure on brain activation and functional connectivity during a recognition memory task. Through joint augmentation of visual area activation, 40-Hz light enhanced brain areas mostly in the limbic system that are related to memory, such as the hippocampus and thalamus. Conversely, 0-Hz light enhanced brain areas mostly in the prefrontal cortex. Additionally, functional connection analysis, with the hippocampus as the seed point, showed that 40-Hz light enhanced connection with the superior parietal lobe and reduced the connection with the default network. These results indicate that light at a frequency of 40 Hz can change the activity and functional connection of memory-related core brain areas. They also indicate that in the use of light to regulate cognitive functions, its frequency characteristics merit attention.

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A32-A32
Author(s):  
W D Killgore ◽  
N S Dailey ◽  
A C Raikes ◽  
J R Vanuk ◽  
E Taylor ◽  
...  

Abstract Introduction Light exposure has powerful effects on the circadian timing of sleep and wake, primarily through the regulation of the secretion of melatonin. However, it is becoming clear that light has additional alerting effects beyond its primary effect on the circadian system. Exposure to light, particularly blue-wavelength light, has been shown to acutely increase brain activation, alertness, and some elementary aspects of cognitive performance such as working memory and emotional anticipation during the day. Whether blue light exposure can have longer-lasting effects on brain activation and performance during more complex cognitive control tasks up to 30-minutes after light cessation is unknown. Methods In a sample of 30 healthy adults, we examined the effects of a single 30-minute exposure to either blue (n=14) or amber placebo (n=16) light on subsequent brain activation and performance during the Multi-Source Interference Task (MSIT) measured a half-hour after light cessation using functional magnetic resonance imaging. Mean activation in all regions showing increased task-related activation (i.e., Task Positive Network; TPN) and regions showing decreased activation (i.e., Default Mode Network; DMN) at p<.001 (FWE corrected) was extracted separately for each network in SPM12 and compared between light conditions. Results Performance metrics for the MSIT, including accuracy, response time, and cognitive throughput, did not differ between the blue and amber conditions, suggesting that performance was sustained equally between light conditions. However, brain activation within the TPN to the interference condition of the MSIT was significantly lower (p=.024) in the blue relative to the amber condition, with no group differences observed for suppression of the DMN. Conclusion Compared to amber, a single exposure to blue light was associated with enhanced neural efficiency a half-hour later as demonstrated by reduced TPN activation to achieve the same level of cognitive performance. Blue light may be an effective method for optimizing neurocognitive performance under some conditions. Support US Army Medical Research and Materiel Command: W81XWH-14-1-0571


SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A442-A442
Author(s):  
A C Raikes ◽  
N S Dailey ◽  
J R Vanuk ◽  
A Alkozei ◽  
M A Grandner ◽  
...  

Abstract Introduction Light exposure, particularly blue wavelength light, has consistent positive effects on daytime sleepiness following mild traumatic brain injuries (mTBIs). While self-perceived improvements in daytime sleepiness are well-documented, the neurobiological underpinnings are not well understood. The purpose of this study was to localize changes in functional connectivity after daily morning blue light therapy (BLT) and to associate these changes with improvements in post-mTBI daytime sleepiness. Methods 29 individuals with a history of mTBI were randomized to receive either BLT (n=13) or placebo amber light (ALT; n=16). All participants self-reported daytime sleepiness (Epworth Sleepiness Scale (ESS); lower is better) and underwent resting-state functional magnetic resonance imaging at pre- and post-treatment. Whole-brain functional connectivity (FC) was estimated as the correlations between 400 cortical regions of interest (ROIs) assigned to 7 resting-state networks. A two-sample T-test for post-treatment ROI-to-ROI FC identified target connections (FDR corrected p<0.01). Post-treatment ESS scores and FC for these connections were correlated for treatment-related brain-behavior associations (uncorrected p<0.05). Results Lower FC after BLT in 4 ROI-to-ROI connections linking the default mode and visual networks was associated with lower ESS scores. Higher FC after BLT in 9 ROI-to-ROI connections linking attention, cognitive control, and visual networks was also associated with lower ESS scores. Conclusion BLT resulted in decreased self-reported daytime sleepiness, which was associated with decoupling of the default mode and visual networks as well as increased connectivity between and within attention and cognitive control networks, suggesting potentially improved attention to relevant stimuli and cognitive processes and less internal mentation. These associations may contribute to improved alertness, attention, and cognitive performance following a mTBI. Further work is needed to identify the optimal timing and dosage of BLT to maximize these outcomes. Support This study was funded by an award to Dr. Killgore from the US Army Medical Research and Materiel Command (USAMRMC; award number: W81XWH-14-1-0571).


2018 ◽  
Vol 56 (01) ◽  
pp. E2-E89
Author(s):  
A Kremer ◽  
T Buchwald ◽  
M Vetter ◽  
A Dörfler ◽  
C Forster

2021 ◽  
pp. 30-33
Author(s):  
David Jaynes ◽  
Paul Switzer

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.


2017 ◽  
Author(s):  
Roel M. Willems ◽  
Franziska Hartung

Behavioral evidence suggests that engaging with fiction is positively correlated with social abilities. The rationale behind this link is that engaging with fictional narratives offers a ‘training modus’ for mentalizing and empathizing. We investigated the influence of the amount of reading that participants report doing in their daily lives, on connections between brain areas while they listened to literary narratives. Participants (N=57) listened to two literary narratives while brain activation was measured with fMRI. We computed time-course correlations between brain regions, and compared the correlation values from listening to narratives to listening to reversed speech. The between-region correlations were then related to the amount of fiction that participants read in their daily lives. Our results show that amount of fiction reading is related to functional connectivity in areas known to be involved in language and mentalizing. This suggests that reading fiction influences social cognition as well as language skills.


2021 ◽  
Author(s):  
Masao Ishizawa ◽  
Takuya Uchiumi ◽  
Miki Takahata ◽  
Michiyasu Yamaki ◽  
Toshiaki Sato

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Nigul Ilves ◽  
Pilvi Ilves ◽  
Rael Laugesaar ◽  
Julius Juurmaa ◽  
Mairi Männamaa ◽  
...  

Perinatal stroke is a leading cause of congenital hemiparesis and neurocognitive deficits in children. Dysfunctions in the large-scale resting-state functional networks may underlie cognitive and behavioral disability in these children. We studied resting-state functional connectivity in patients with perinatal stroke collected from the Estonian Pediatric Stroke Database. Neurodevelopment of children was assessed by the Pediatric Stroke Outcome Measurement and the Kaufman Assessment Battery. The study included 36 children (age range 7.6–17.9 years): 10 with periventricular venous infarction (PVI), 7 with arterial ischemic stroke (AIS), and 19 controls. There were no differences in severity of hemiparesis between the PVI and AIS groups. A significant increase in default mode network connectivity (FDR 0.1) and lower cognitive functions (p<0.05) were found in children with AIS compared to the controls and the PVI group. The children with PVI had no significant differences in the resting-state networks compared to the controls and their cognitive functions were normal. Our findings demonstrate impairment in cognitive functions and neural network profile in hemiparetic children with AIS compared to children with PVI and controls. Changes in the resting-state networks found in children with AIS could possibly serve as the underlying derangements of cognitive brain functions in these children.


2018 ◽  
Vol 29 (5) ◽  
pp. 1984-1996 ◽  
Author(s):  
Dardo Tomasi ◽  
Nora D Volkow

Abstract The origin of the “resting-state” brain activity recorded with functional magnetic resonance imaging (fMRI) is still uncertain. Here we provide evidence for the neurovascular origins of the amplitude of the low-frequency fluctuations (ALFF) and the local functional connectivity density (lFCD) by comparing them with task-induced blood-oxygen level dependent (BOLD) responses, which are considered a proxy for neuronal activation. Using fMRI data for 2 different tasks (Relational and Social) collected by the Human Connectome Project in 426 healthy adults, we show that ALFF and lFCD have linear associations with the BOLD response. This association was significantly attenuated by a novel task signal regression (TSR) procedure, indicating that task performance enhances lFCD and ALFF in activated regions. We also show that lFCD predicts BOLD activation patterns, as was recently shown for other functional connectivity metrics, which corroborates that resting functional connectivity architecture impacts brain activation responses. Thus, our findings indicate a common source for BOLD responses, ALFF and lFCD, which is consistent with the neurovascular origin of local hemodynamic synchrony presumably reflecting coordinated fluctuations in neuronal activity. This study also supports the development of task-evoked functional connectivity density mapping.


2002 ◽  
Vol 14 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Paul J Reber ◽  
Eric C Wong ◽  
Richard B Buxton

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